Energy Efficiency Study in Building Sector 18 January 2014
Prepared for
Research & Development Division , Department of
Renewable Energy, MoEA, Thimphu, Bhutan
and
UNDAF,
United Nations Development Programme
Thimphu, Bhutan
Department of Renewable Energy, Ministry of Economic Affairs, Royal Government of Bhutan
Acknowledgement
PwC wishes to thank the Department of Renewable Energy (DRE), Ministry of Economic Affairs (MoEA), for
initiating United Nations Development Programme (UNDP) funded project "Energy Efficiency Study in
Building Sector" and engaging PwC India to offer consulting services for the same.
We wish to thank Mr. Karma Tshering, Director, Ms. Dawa Zangmo, Chief Engineer, Mr. Chhimi Dorji,
Executive Engineer, Mr. Sherab Jamtsho, Deputy Executive Engineer and the whole staff of Department of
Renewable Energy for their time and extended co-operation to us.
We wish to express appreciation for co-operation extended to us by the different prestigious buildings to
undertake energy audits in their premises.
We also wish to convey special thanks to Bhutan Power Corporation Limited, for their support in providing all
necessary information and energy consumption data for buildings in various Dzongkhags, captured during
questionnaire survey and detailed energy audits.
The support from various other stakeholders has also been commendable. The successful completion of project
would not have been possible without the support of the different stakeholders who participated in the
stakeholder meeting and provided valuable inputs.
Department of Renewable Energy, Ministry of Economic Affairs, Royal Government of Bhutan
Table of contents
1. Project Objective & Approach 9
1.1. Project objective 9
1.2. Approach adopted to develop energy audit reports of buildings 9
1.2.1. Review of EE policies and initiatives undertaken in the building sector 10
1.2.2. Project inception 10
1.2.3. Assessment of buildings for energy audits 10
1.2.4. Designing of data collection framework 12
1.2.5. Stage 1 -Primary questionnaire survey (walk through audits) 13
1.2.6. Stage 2 -Detailed energy audit 14
2. Building Energy Audit 16
2.1. Case study 1- Institutional building at Thimphu 17
2.1.1. Backdrop 17
2.1.2. Energy consumption and data recording 18
2.1.3. Construction practices at the building 18
2.1.4. Connected load of the building 19
2.1.5. Recommendations 20
2.2. Case study 2- Commercial building at Trongsa 21
2.2.1. Backdrop 21
2.2.2. Energy consumption and data recording 22
2.2.3. Construction practices at the building 23
2.2.4. Connected load at the building 23
2.2.5. Recommendations 25
2.3. Case study 3- Domestic household at Bumthang 26
2.3.1. Backdrop 26
2.3.2. Energy consumption data 26
2.3.3. Construction practices at the households 27
2.3.4. Connected load at urban and rural households 28
2.3.5. Firewood usage at urban and rural households 29
2.3.6. Recommendations 30
2.4. Summary of the observations of practices 32
2.4.1. Lighting 32
2.4.2. Heating Ventilation & Air Conditioning (HVAC) 32
2.4.3. Air conditioning 32
2.4.4. Space heating (through electric room heaters) 32
2.4.5. Fans 33
2.4.6. Office and other general equipments 33
Department of Renewable Energy, Ministry of Economic Affairs, Royal Government of Bhutan
2.4.7. Firewood usage 33
2.4.8. Construction practices 33
3. Status of Building Regulations in Bhutan – Standards and Bodies 35
4. International review programs on BEECs 37
5. Climate Zones determination for Bhutan 40
6. Construction Practices 42
6.1. Integration of modern construction designs with traditional features 42
6.1.1. Orientation and shape of the building 42
6.2. Building element construction 46
6.2.1. Foundations 46
6.2.2. Walls 46
6.2.3. Rabsel 47
6.2.4. Openings -Doors and windows 49
6.2.5. Kachhen and Zhu 50
6.2.6. Cornices 51
6.2.7. Roof 51
7. Key inputs or the Approach for the EE plan in buildings 53
8. Efficient and Integrated Design Processes 54
9. Green Building and Passive Guidelines 57
9.1. Alternative Building Materials 57
9.2. Orientation 59
9.2.1. Space orientation 59
10. Building Energy Efficiency Code, 68
11. Implementation Framework 74
11.1. Key actions required for implementation 76
11.1.1. Policy development 76
11.1.2. Market assessment 76
12. Policy Instruments - Recommendations 79
12.1. Introduction of Energy Conservation (EC) Act in Bhutan 79
12.2. Launch of Standard & Labeling (S&L) program 80
12.3. Energy Audits for different buildings in Bhutan 81
12.4. Implementation of BEEC (Building Energy Efficiency Code) 81
12.5. Launch of program for efficiency of Bukhari system 82
12.6. Initiate capacity building programs and strengthen ongoing awareness programs 83
12.7. Energy efficiency policy requirements 85
Department of Renewable Energy, Ministry of Economic Affairs, Royal Government of Bhutan
List of Annexures
Annexure Details Annexure A Energy Audit Report - Tashichho Dzong, Thimphu
Annexure B Energy Audit Report - Bhutan Power Corporation, Corporate Head Office, Thimphu
Annexure C Energy Audit Report - Energy Building, Ministry of Economic Affairs, Thimphu
Annexure D Energy Audit Report - Phuentsholing General Hospital, Phuentsholing
Annexure E Energy Audit Report - Hotel Bhutan Residence, Phuentsholing
Annexure F Energy Audit Report - Yangkhil Resort, Trongsa
Annexure G Energy Audit Report - Trongsa General Hospital, Trongsa
Annexure H Energy Audit Report - Urban & Rural Households, Bumthang
Annexure I Energy Audit Report - Hotel Druk Zhongar, Mongar
Annexure J Energy Audit Report - NRDCL , Mongar
Annexure K Energy Audit Report - Urban & Rural Households, Mongar
Annexure L Bhutan Building Energy Efficiency Code (BEEC)
Annexure M Stakeholder Presentation
* Each of the above annexure is a detailed report which provides the findings obtained in this project. These
annexure are attached separately with this document.
List of Tables
Table 1: Details of questionnaire survey undertaken in Bhutan ............................................................................... 13 Table 2: Details of detailed energy audit undertaken in Bhutan .............................................................................. 14 Table 3 : Measurement and recordings undertaken during detailed energy audit ................................................. 15 Table 4: Building details for energy audit .................................................................................................................. 16 Table 5: General building details I ............................................................................................................................. 17 Table 6: General building details II ............................................................................................................................ 17 Table 7: Energy Performance Index: Institutional building from 2010-11 to 2012-13 ............................................ 18 Table 8: Construction Practices: Institutional building ............................................................................................ 18 Table 9: Electricity consuming sections at building .................................................................................................. 19 Table 10: Recommendations for Institutional building ........................................................................................... 20 Table 11: General building details I- Commercial building ....................................................................................... 21 Table 12: General building details II - Commercial building ................................................................................... 22 Table 13: Energy Performance Index: Commercial building from 2011-12 to 2012-13 .......................................... 22 Table 14: Construction Practices: Institutional building ......................................................................................... 23 Table 15: Electricity consuming sections at commercial building ........................................................................... 24 Table 16: Recommendations for the commercial building ...................................................................................... 25 Table 17: Domestic household details ....................................................................................................................... 26 Table 18: Energy consumption details: Urban and Rural households .................................................................... 27 Table 19: Details of different household building envelope ..................................................................................... 27 Table 20: Details of firewood consumption at households ...................................................................................... 29 Table 21: Recommendations for domestic households ............................................................................................ 30 Table 22: International review of different building energy efficiency programs .................................................. 37 Table 23: Bhutan specific Köppen-Geiger climate classification .............................................................................. 41 Table 24: Different building materials and their attributes - Examples from Bhutan ........................................... 42 Table 25: General guidelines for foundation dimensions in Bhutan ....................................................................... 46 Table 26: Key performance indicators for fenestration ............................................................................................ 71 Table 27: Key performance indicators for HVAC ...................................................................................................... 71 Table 28: Key performance indicators for lighting ................................................................................................... 72 Table 29: Flowchart for different stages of building energy efficiency code for Bhutan ........................................ 74 Table 30: Ranking of policy options for standards and labeling of appliances ....................................................... 81
Department of Renewable Energy, Ministry of Economic Affairs, Royal Government of Bhutan
List of Figures
Figure 1: Project objective ............................................................................................................................................ 9 Figure 2: Project approach ........................................................................................................................................... 9 Figure 3: Bhutan building sector percentage electricity consumption share for 2011 ............................................ 11 Figure 4: Climate zone map of Bhutan ....................................................................................................................... 11 Figure 5: Region wise electricity consumption in buildings in Bhutan in 2011 ....................................................... 12 Figure 6: Regions covered during questionnaire survey ........................................................................................... 13 Figure 7: Building types captured during questionnaire survey ............................................................................... 13 Figure 8 : Regions covered during detailed energy audit .......................................................................................... 14 Figure 9: Building types captured during energy audit ............................................................................................. 14 Figure 10:Active power and electricity consumption profile of Institutional building ........................................... 18 Figure 11:Percentage load distribution at building .................................................................................................... 19 Figure 12: Commercial building - resort at Trongsa ................................................................................................. 21 Figure 13:Active power and electricity consumption profile of commercial building ............................................ 22 Figure 14: Percentage load distribution at commercial building ............................................................................. 23 Figure 15:Percentage load distribution at urban and rural households .................................................................. 28 Figure 16: Traditional bukhari system ...................................................................................................................... 29 Figure 17: Climate zone for Bhutan : Geographic regions overlaid on the administrative regions of Bhutan ...... 40 Figure 18: Traditional building in Bhutan (depicting a rabsel on the side of the wind direction) ........................ 42 Figure 19 : Tapering walls at Bhutan ......................................................................................................................... 47 Figure 20 : Rabsel in walls ......................................................................................................................................... 47 Figure 21 : Types of rabsels used in walls in Bhutan ................................................................................................ 49 Figure 22 : Traditional windows in Bhutan .............................................................................................................. 49 Figure 23 : Traditional windows in Bhutan .............................................................................................................. 50 Figure 24 : Kachhen and zhu timber columns for load bearing in ceilings ............................................................. 50 Figure 25 : Cornices in the walls ................................................................................................................................. 51 Figure 26 : Types of roofs in Bhutan ......................................................................................................................... 52 Figure 27: Different stakeholder involved in building design.................................................................................. 54 Figure 28: Passive/ bio-climate design strategies ..................................................................................................... 57 Figure 29: Ground Insulation .................................................................................................................................... 60 Figure 30: Plinth protection provided by sloping paving for drainage channel ...................................................... 61 Figure 31: Snapshot of a 40 cm gable wall compound insulation system and a porous ceramics brick ............... 62 Figure 32: An inclined roof with insulation with respect to the rafters and highly insulated concrete roof
construction ................................................................................................................................................................ 62 Figure 33: Snapshot for thermal mass in a building ................................................................................................ 63 Figure 34 : Pictorial representation of radiation of heat during day and night ...................................................... 63 Figure 35: Construction from rammed earth ............................................................................................................ 64 Figure 36: Pictorial representation of working of Trombe wall ............................................................................... 65 Figure 37: Working of Trombe wall in respect to day and night ............................................................................. 66 Figure 38: Trombe wall vs. sun space ....................................................................................................................... 66 Figure 39: Types of ventilation that can be implemented in Bhutan ...................................................................... 67 Figure 40: Sealing tape for plaster for air tightness ................................................................................................. 67 Figure 41: Methodology for building energy code compliance ................................................................................ 68 Figure 42: Steps for implementation, enforcement and stability of code ................................................................ 77
Department of Renewable Energy, Ministry of Economic Affairs, Royal Government of Bhutan
List of Abbreviations and Acronyms
MoEA Ministry of Economic Affairs
DRE Department of Renewable Energy
UNDP United Nations Development Programme
BPC Bhutan Power Corporation
ADB Asian Development Bank
DES Department of Engineering Services
MoWHS Ministry of Works and Human Settlements
HVAC Heating Ventilation and Air Conditioning
UPS Uninterrupted Power Supply
LPG Liquefied Petroleum Gas
kW Kilowatt
EPI Energy Performance Index
kWh Kilowatt-hour
BEE Bureau of Energy Efficiency
FTL Fluorescent Tube Light
LED Light Emitting Diode
A.C. Air Conditioning
EER Energy Efficiency Ratio
COP Coefficient of Performance
CFL Compact Fluorescent Lamp
IRR Internal Rate of Return
GHG Green House Gas
CRT Cathode Ray Tube
LCD Liquid Crystal Display
ECM Energy Conservation Measure
S&L Standard & Labeling
BEEC Building Energy Efficiency Code
NSB National Statistics Bureau
BSB Bhutan Standards Bureau
BSQC Bureau of Standards and Quality Control
BMS Building Management System
BBR Bhutan Building Rules - 2002
IS Indian Standards
PWD Public Works Department
ASHRAE American Society of Heating Refrigeration and Air Conditioning Engineers
ASTM American Society for Testing and Materials
ISO International Organization for Standardization
EE Energy Efficiency
LCCA Life Cycle Cost Analysis
CSEB Compressed Stabilized Earth Block
HI Hollow Interlocking
ECBC Energy Conservation Building Code
EPS Expanded Polystyrene
XPS Extruded Polystyrene
PUF Polyurethane Foam
Department of Renewable Energy, Ministry of Economic Affairs, Royal Government of Bhutan
KPI Key Performance Indicators
SHGC Solar Heat Gain Coefficient
U Value Heat Transfer Coefficient
VLT Visible Light Transmission
RCC Reinforced Concrete Cement
AAC Autoclaved Aerated Concrete
BTU British Thermal Unit
CRI Color Rendering Index
CCT Correlated Color Temperature
PMU Project Management Unit
LPD Lighting Power Density
EC Energy Conservation
US EPA United States - Environmental Protection Agency
Nu Ngultrum (BTN)
Department of Renewable Energy, Ministry of Economic Affairs, Royal Government of Bhutan
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1. Project Objective & Approach
1.1. Project objective
The project "Development of Energy Codes and Standards for Buildings in Bhutan" aimed at following
three objectives as presented in the Figure 1
Figure 1: Project objective
The tasks outlined above are interdependent on each other. Keeping in view the project objectives , as
standard approach was followed to achieve the proposed outcomes. The outputs from each task were
input in designing the requirements of the next task.
1.2. Approach adopted to develop energy audit reports of buildings
The approach followed for the project is presented in Figure 2.
Figure 2: Project approach
Evaluate the Building Sector and Prepare Detailed Energy Audit Reports
Develop Energy Codes and Standards for Buildings
Recommend Policy Instruments
Review of EE Policies and Initiatives
Undertaken in the Building Sector
Inception Meeting /Assessment of Stakeholders
Assessment of Buildings for Energy
Audits
Designing of Data Collection
Framework
Questionnaire Survey (Walk
through Audit)
Detailed Energy Audits and Energy
Audit Reports
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1.2.1. Review of EE policies and initiatives undertaken in the building sector
Extensive research activity was undertaken to collect the information on the current scenario with
respect to policies and initiatives which drive energy efficiency in the building sector in Bhutan. List of
few important documents reviewed is presented below :
Energy Efficiency Technical Report Bhutan - ADB 2012
Bhutan Energy Efficiency Baseline Study - DRE and UNDP
Bhutan Energy Sector - ADB Evaluation Study
Bhutan Green Building Guidelines Draft - DES, MWHS
Bhutan National Urbanization Strategy, Ministry of Works & Human Settlement - 2008
Bhutan Power Corporation Limited, Tariff Review report - October 2013
Rules of Income Tax Act of the Kingdom of Bhutan, 2001
Key information extracted from these documents include the following aspects related to Bhutan .
Policy and regulatory mechanism in place
Energy baseline scenario in Bhutan
Financial instruments in place
Power scenario and tariff structure
Consumer profile and end usage pattern
Building structure and energy consumption profile
1.2.2. Project inception
An inception meeting with the DRE, was organized on 11th September 2013 to kick-off the project and
discuss the proposed approach. The outcomes of the meeting are outlined below:
The DRE agreed to facilitate/help with the authority letter/support letter for undertaking
audits in different buildings across Bhutan.
A draft data collection framework was agreed with the DRE.
Agreed to undertake the audits in two stages. First stage involve primary questionnaire survey
(walk through) of buildings across Bhutan.
The second stage involves detailed energy of few buildings covering all important regions of
Bhutan.
The DRE agreed to support in facilitating connect with different stakeholders in Bhutan.
1.2.3. Assessment of buildings for energy audits
It was established from the previous studies conducted by the DRE, that the building sector in Bhutan
consumes around 16% of the total energy (including electrical and thermal). The building sector in
Bhutan nearly accounted for 250 GWh of electricity consumption in the year 2011. To carry out the
assessment, the building sector in Bhutan was broadly classified into the following:
Domestic households (urban & rural)
Commercial establishments
Institutional buildings
Department of Renewable Energy, Ministry of Economic Affairs, Royal Government of Bhutan
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Figure 3: Bhutan building sector percentage electricity consumption share for 20111
After the electricity consumption break up in the building sector was established, region-wise
electricity consumption profiles for buildings were drawn up to assess the major electricity consuming
regions in Bhutan . To understand the region and climate zones of Bhutan, the Bhutan map and
different climatic zones were studied to plan the coverage of study. The climatic zone map of Bhutan
is presented at Figure 4.
Figure 4: Climate zone map of Bhutan
For the analysis of building performance, it is important to classify the buildings and their existence in
different climatic zones. The climatic conditions impact the energy consumption in a building. As
presented above, Bhutan climatic zone comprises three zones i.e. Alpine, Mid Montana and Sub
Tropical.
1 Bhutan Energy Efficiency Baseline Study, Dec 2012, DRE
Urban Households
38%
Rural Households
26%
Institutional buildings
19%
Commercial Establishment
17%
Percentage electricity consumption in 2011
Department of Renewable Energy, Ministry of Economic Affairs, Royal Government of Bhutan
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From previous studies conducted by the DRE, it was established that, buildings in the western region
of Bhutan consumes close to 62% of the total electricity in buildings in Bhutan. Thimphu, Chhukha
and Paro are the dominant electricity consuming dzongkhags in western region . The break- up of
electricity consuming areas and their distribution is presented at Figure 5.
Figure 5: Region wise electricity consumption in buildings in Bhutan in 20112
To develop an assessment plan for buildings, the following criteria were used to select buildings.
Type of buildings ( domestic, institutional and commercial)
Climatic zone ( alpine, mid-montana and sub-tropical)
Region ( eastern, central and western)
Energy consumption pattern
As evident from Figure 4 and Figure 5, most of the criteria's were covered with the help of energy
audits of buildings falling in Thimpu, Paro and Chhukha as they cover all the climatic zones and have
substantial share in the total energy consumption in Bhutan. But for the overall status of buildings in
different regions of Bhutan and also to cover rural households, a sample was developed to cover all the
important regions.
1.2.4. Designing of data collection framework
After assessing the selection criteria of buildings for energy audits in Bhutan, a data collection
framework was designed and shared with the DRE. The data collection framework captured the
following areas:
1. Total energy load of the building and built up area
2. Energy consumption/end use consumption (electrical & thermal)
Lighting
HVAC
Heating systems (space heating)
Water heating system
Ceiling fans
Others
2 Bhutan Energy Efficiency Baseline Study, Dec 2012, DRE
Thimphu 41%
Chhukha 12%
Paro 9%
Gelephu 5%
Punakha 5%
Samste 3%
Others 25%
Percentage Electricity Consumption in 2011
Department of Renewable Energy, Ministry of Economic Affairs, Royal Government of Bhutan
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3. Building envelope and construction practices( for input to building code)
Wall/roof/ceiling
Windows and doors
Fenestration
Insulation
Traditional construction practices
1.2.5. Stage 1 -Primary questionnaire survey (walk through audits)
An initial questionnaire survey (walk through audits) was undertaken to analyze the building to be
considered for detailed energy audits. The questionnaire survey captured all the zones and regions of
Bhutan. The break- up of sample of buildings covered in different building type categories and their
regional break up provided in the Table 1.
Table 1: Details of questionnaire survey undertaken in Bhutan
Dzongkhags/ Building types
Institutional
buildings
Commercial establishments
Urban domestic
Rural domestic
Total
Thimphu 13 13 6 6 38
Chhukha 5 5 5 3 18
Paro 5 5 4 3 17
Samtse 2 2 2 2 8
Wangdi 2 2 2 2 8
Trongsa 2 2 2 2 8
Bumthang 2 2 2 2 8
Mongar 2 2 2 2 8
Total 33 33 25 22 113
Figure 6: Regions covered during questionnaire survey
Figure 7: Building types captured during questionnaire survey
It can be seen from Table 1 and
Figure 6 that questionnaire survey captured all the zones, regions and building types for the
assessment. The following outcomes were achieved through walk through audits:
29%
29%
22%
20%
Building types for questionnaire survey
Institutional Buildings
Commercial Establishments
Urban Domestic
Rural Domestic
Department of Renewable Energy, Ministry of Economic Affairs, Royal Government of Bhutan
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Overall energy consumption of different building types was established
Total building area of buildings
Availability of detailed end use consumption data and the electricity bills of the last few years
All the information gathered through walk through audits were useful to shortlist buildings for
detailed energy audits.
1.2.6. Stage 2 -Detailed energy audit
Sample buildings for detailed energy audits were finalized from questionnaire survey of the building
sample considering following different parameters:
Energy consumption pattern of the buildings surveyed
Different loads observed during walk through
Construction practices
Regions and zones in Bhutan
Availability of data and willingness of building owners
The details of buildings and regions captured during detailed energy audit are provided at Table 2.
Table 2: Details of detailed energy audit undertaken in Bhutan
S.No Building
types
Thimphu Chhukha Trongsa Bumthang Mongar Total
1 Institutional
buildings
4 1 1 - 1 7
2 Commercial
establishments
- 1 1 1 1 4
3 Urban domestic 1 - - 2 2 5
4 Rural domestic - - - 2 2 4
Total 5 2 2 5 6 20
Figure 8 : Regions covered during detailed energy audit
Figure 9: Building types captured during
energy audit
It can be seen from Table 2 and Figure 8 that energy audit captured all the zones, regions and building
types for the assessment. The components undertaken in the detailed energy audit are presented at
Table 3
35%
20% 25%
20%
Building for detailed energy audit
Institutional Buildings
Commercial Establishments
Urban Domestic
Rural Domestic
Department of Renewable Energy, Ministry of Economic Affairs, Royal Government of Bhutan
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Table 3 : Measurement and recordings undertaken during detailed energy audit
S.No Areas of energy audit Assessment of areas of energy audit
Mode of assessment
1 Electrical recording (24 hour data was recorded )
Energy consumption Krykard three phase meter
Active power consumption Krykard three phase meter
Apparent power consumption Krykard three phase meter
Power factor Krykard three phase meter
Frequency Krykard three phase meter
2 Lighting
Lux levels Testo lux meter
Lighting points assessment Audit observation
Types of lighting and consumption, fixtures
Audit observation
3 HVAC Humidity & Temperature Testo Hygrometer
Rated values of heating and cooling equipments
Audit observation
4 Room heaters Power consumption in room heaters Krykard single phase meter
Humidity and temperature Testo hygrometer
5 Ceiling fans Power consumption Krykard single phase meter
6 Water heating system Rated values Audit observation
7 General office equipments
Rated values Audit observation
8 Kitchen/laundry/special equipments
Rated values Audit observation
9 Building envelope
Wall/ roof / ceiling Discussion and audit observation
Windows and doors Measurement, discussion and Audit observation
Fenestration Discussion and audit observation
Insulation Discussion and audit observation
Traditional construction practices Discussion and audit observation
10 Bukhari system
Firewood consumption Discussion and audit observation
Space heating Discussion and audit observation
Outlines of energy audits are discussed in the next chapter.
Department of Renewable Energy, Ministry of Economic Affairs, Royal Government of Bhutan
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2. Building Energy Audit
The detailed energy audit was useful to assess the energy consumption profile in buildings and types
in different regions/zones. Building audits also helped assess end -use energy consumption in
buildings and the efficiency of different energy consuming equipments and appliances.
As discussed in the previous section, a total of 20 buildings were considered for detailed energy audits.
The details of buildings considered for energy audits are presented at Table 4:
Table 4: Building details for energy audit
Buildings (Coded)
Region Building type
Climatic zone
Built up area (Sq. m)
Annual energy consumption (2012-13) (kWh/year)
Energy Performance Index (2012-13) (kWh/Sq.m/year)
Building 1 Thimphu, western Bhutan
Institutional Mid-montana
6605 314010 47.54
Building 2 Thimphu, western Bhutan
Institutional Mid-montana
4380 309420 70.64
Building 3 Thimphu, western Bhutan
Institutional Mid-montana
680 62000 91.18
Building 4 Thimphu, western Bhutan
Institutional Alpine and Mid-montana
5172.16 383200 74.09
Building 5 Thimphu, western Bhutan
Domestic urban
Mid-montana
278.7 31531 113.14
Building 6 Phuentsholing, south -western Bhutan
Institutional Sub-tropical 6320 257847 40.80
Building 7 Phuentsholing, south -western Bhutan
Commercial Sub-tropical 976 74960 76.80
Building 8 Trongsa, central Bhutan
Commercial Mid-montana
1586.3 184860 116.5
Building 9 Trongsa, central Bhutan
Institutional Mid-montana
2048.5 60900 29.7
Building 10
Bumthang, central Bhutan
Commercial Alpine and Mid-montana
5785 303161 52.19
Building 11
Bumthang, central Bhutan
Domestic urban
Alpine and Mid-montana
93.5 859 9.19
Building 12
Bumthang, central Bhutan
Domestic urban
Alpine and Mid-montana
106.3 1648 15.50
Building 13
Bumthang, central Bhutan
Domestic rural
Alpine and Mid-montana
83.1 449 5.40
Building 14
Bumthang, Central Bhutan
Domestic rural
Alpine and Mid-montana
83.2 3389 40.73
Building 15
Mongar, eastern Bhutan
Commercial Mid-montana
1152.6 38240 33.2
Building 16
Mongar, eastern Bhutan
Institutional Mid-montana
662.3 28287 42.7
Building 17
Mongar, eastern Bhutan
Domestic urban
Mid-montana
51.5 1258 24.43
Department of Renewable Energy, Ministry of Economic Affairs, Royal Government of Bhutan
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Building 18
Mongar, eastern Bhutan
Domestic urban
Mid-montana
51.5 696 13.51
Building 19
Mongar, eastern Bhutan
Domestic rural
Mid-montana
84.9 1849 21.78
Building 20
Mongar, eastern Bhutan
Domestic rural
Mid-montana
55.3 904 16.35
Intentionally, the names of the buildings are not shared in the report. The purpose is to understand
the practices in different building types in Bhutan.
As such detailed energy audits reports of some of the important buildings have been prepared and
attached in Annexure, and audit results of some building types have been discussed as case studies.
The detailed energy audit report of some important buildings are provided from Annexure A to
Annexure K. Following building types is discussed in next section as case study for this report.
Institutional building at Thimphu
Commercial building at Trongsa
Domestic household at Bumthang
2.1. Case study 1- Institutional building at Thimphu
The components of energy audit captured are discussed next in brief:
2.1.1. Backdrop
Table 5: General building details I
Sr. no Particulars Details
1 Date of energy audit 21 October 2013
2 Climatic zone Mid- montana
3 Building type Institutional
4 Year of operation November 2009
5 Total complex area (sq m) 10617
6 Total built-up area (sq m) 4380
7 Source of energy Electricity
8 Any other energy source Battery bank, UPS for the server room and LPG for cooking
9 Office operating days Monday to Friday
10 Office operating hours 9 am to 5:30 pm
11 Sanctioned load 384 kW
12 Consumer no 100000667 and 100000678
The building complex had three buildings in its complex under the same meter. The details of the individual building are provided at Table 6.
Table 6: General building details II
Buildings Built up area No of storied
Main building 3356 sq. m Basement + G +4+ Jamtho
Annex I 409 sq. m G+1
Annex II 614 sq. m Basement + G + 1. It has kitchen & canteen in the basement
Department of Renewable Energy, Ministry of Economic Affairs, Royal Government of Bhutan
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2.1.2. Energy consumption and data recording
Energy consumption data for the past three years was extracted from Bhutan Power Corporation
(BPC) to assess the actual Energy Performance Index(EPI) of the building as presented in Table 7.
Table 7: Energy Performance Index: Institutional building from 2010-11 to 2012-13
Parameters 2010-11 2011-12 2012-13
Units consumed (kWh/year) 212640 308400 309420
Built-up area (sq.m) 4380 4380 4380
EPI index (kWh/sq.m/year) 48.55 70.41 70.64
Electrical load profiling was recorded for 24 hours using the krykard three phase power analyzer. The
total building load during the day of recording and total electricity consumption are presented in
Figure 10.
Figure 10:Active power and electricity consumption profile of Institutional building
Total electricity consumption (kWh) of the building measured during 24 hours is
2,045 kWh.
2.1.3. Construction practices at the building
The energy audit included capturing construction practices as well as components of the building envelope (exterior shell).The components of a building envelope include exterior walls, foundation, and the roof. Energy use within the building is dependent on materials used and construction practices adopted. The details of construction material used at the building are presented at Table 8.
Table 8: Construction Practices: Institutional building
Parameters Material Insulation Age ( Years) Condition U -value (W/m2K)
Walls Solid brick wall (brick
228 mm, plaster)
No 4 Good Approx 2.11
0 20 40 60 80
100 120 140 160
9:2
0:0
0 A
M
11:0
0:0
0 A
M
12:4
0:0
0 P
M
2:2
0:0
0 P
M
4:0
0:0
0 P
M
5:4
0:0
0 P
M
7:2
0:0
0 P
M
9:0
0:0
0 P
M
10:4
0:0
0 P
M
12:2
0:0
0 A
M
2:0
0:0
0 A
M
3:4
0:0
0 A
M
5:2
0:0
0 A
M
7:0
0:0
0 A
M
8:4
0:0
0 A
M
Active power profile - kW
kW
0
500
1000
1500
2000
2500
9:2
0:0
0 A
M
11:1
0:0
0 A
M
1:0
0:0
0 P
M
2:5
0:0
0 P
M
4:4
0:0
0 P
M
6:3
0:0
0 P
M
8:2
0:0
0 P
M
10:1
0:0
0 P
M
12:0
0:0
0 A
M
1:5
0:0
0 A
M
3:4
0:0
0 A
M
5:3
0:0
0 A
M
7:2
0:0
0 A
M
9:1
0:0
0 A
M
Electricity consumption profile - kWh
kWh
Department of Renewable Energy, Ministry of Economic Affairs, Royal Government of Bhutan
Energy Efficiency Study in Building Sector
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Ceiling Reinforced cement
concrete (concrete cast
dense reinforced)
No 4 Good Bet. 2.5 - 3.0
Roof GI sheets/wooden truss
(no insulation)
No 4 Good Bet. 0.9 to 1
Building fenestration was also captured during the audit. Following are the highlights:
Newly constructed window and good capacity to capture daylight
All single pane glass have an aluminium frame
All windows are provided with curtains
The main building has a glass wall at the front
2.1.4. Connected load of the building
Connected load of the building was captured during the energy audit to assess the percentage of
different energy consuming loads installed at the building. The list of different electricity consuming
sections and their percentage load distribution are
provided at Table 9 and Figure 11.
Table 9: Electricity consuming sections at building
Sr. no
Electricity consuming sections
Total load (kW)
1 HVAC 626.37
2 Office equipments 71.86
3 Only heating (room heaters)
48
4 Lighting 30.024
5 Kitchen & lift load 12.79
Total 789
Figure 11:Percentage load distribution at building
Important observations from energy audit are provided below:
HVAC is the major load with 79% share.3
Split air conditioners are used only at the data centre and control room for process requirement and not for comfort. ACs installed are either no star or BEE’s 2 star labeled.
55% of the total lighting load is covered by T12.
Radiator type heaters were used which consumes nearly 20% more power than the rated value.
It can be established that, lightings and air conditioners installed are not that efficient. Introduction of energy efficient lightings & air conditioners can significantly reduce the energy consumption at the premises. Therefore recommendations were suggested and cost benefit analysis of different options were done to identify most cost effective options.
3 During the study, the HVAC load was not operational as there was no heating requirements.
79%
9% 6% 4% 2%
Load distribution at the building
HVAC
Office Equipments
Only Heating (Room Heaters)
Lighting
Kitchen & Lift Load
Department of Renewable Energy, Ministry of Economic Affairs, Royal Government of Bhutan
Energy Efficiency Study in Building Sector
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2.1.5. Recommendations Table 10: Recommendations for Institutional building
Sr. no
Suggested measure Annual energy saved (kWh/year)
Annual monetary savings ( Nu/year)
Anticipated investment (Nu)
Simple payback period (months)
Discounted payback (months)
Internal rate of return
GHG reduction (tonne of CO2/year) (Considering saved energy is exported to India)
Lighting
1 Use of electronic chokes with inherent losses of 1 W instead of the copper chokes with inherent losses of 14 W(magnetic) in all T12 FTLs (40W)
9,195 19,769 56,910 35 50 (Less than equipment life)
25.17 7.82
2 Replacement of T12 FTLs (40W) that have magnetic ballast with energy efficient T5 FTLs (28 W) that have electronic ballast
18,390 39,539 1,13,820 35 50 (more than equipment life)
16.31 15.63
3 Replacement of T12 FTLs (40W) that have magnetic ballast with the latest LED based tube lights (18W)
25,463 54,745 5,69,100 125 More than equipment life
4.74 (Not feasible)
21.64
AC
1 Replacement of 2 ton 1 star split AC (EER - 2.62 ) with 2 ton 5 star split AC (EER - 3.31)
53,668 1,15,386 5,48,625 57 88 (more than equipment life)
11.76 45.62
2 Replacement of 1.5 ton 1 star split AC (EER - 2.6 ) with 1.5 ton 5 star split AC (EER - 3.31)
30,065 64,640 3,27,600 61 99 (more than equipment life)
11.65 25.56
3 Replacement of 2 ton 1 star split AC (EER - 2.62 ) with 2 ton 3 star split AC (EER - 2.91)
25,656 55,160 4,52,183 98 More than equipment life
Not feasible 21.81
4 Replacement of 1.5 ton 1 star split AC (EER - 2.6 ) with 1.5 ton 3 star split AC (EER - 2.91)
14,931 32,102 2,62,920 98 More than equipment life
Not feasible 12.69
From all the options discussed above, option 1 and 2 in lighting gives best replacement rationale having positive IRR. As the electricity cost in Bhutan is very less compared to other developing or developed countries, these options don't reflect very attractive payback in monetary terms but their energy consumption reduction potential remains very high.
Department of Renewable Energy, Ministry of Economic Affairs, Royal Government of Bhutan
Energy Efficiency Study in Building Sector
PwC 21
2.2. Case study 2- Commercial building at Trongsa
Snapshot of commercial building is provided at Figure 12. The components of energy audit captured at
commercial building are discussed next in brief:
Figure 12: Commercial building - resort at Trongsa
2.2.1. Backdrop
Table 11: General building details I- Commercial building
S. No. Particulars Details
1 Date of energy audit 21st November 2013
2 Building type Commercial building - Resort
3 Year of establishment 2007
4 Total built-up area 1586.3 m2
5 Contact person Mr. Kamal (Manager), Contact no. 975 17745930
6 Primary source of energy at building
Electricity
7 Climatic zone Mid- montana
8 Other sources of energy Wood for space heating at restaurant only and LPG for cooking food
9 Operating hours
The facility remains open throughout the year (24 hours, 365 days). However, the electrical load will not be full for the entire year and will vary as per the usage. Thus, based on discussion with resort staff, the average actual working hours (for electricity usage) per day has been considered as 14 hours.
Department of Renewable Energy, Ministry of Economic Affairs, Royal Government of Bhutan
Energy Efficiency Study in Building Sector
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10 Sanctioned load 100 kW
11 Consumer No. 60000370
The commercial building is a resort at Trongsa. The facility has total 21 rooms for guests categorized into two different types, standard room and deluxe room. The complete bifurcation of different sections in the facility is provided at Table 12.
Table 12: General building details II - Commercial building
S. No. Different sections at the facility premises No. of rooms of each type
1 Standard room 20
2 Deluxe room 1
3 Kitchen 1
4 Restaurant 1
5 Reception lobby 1
6 Laundry 1
7 Conference hall 1
2.2.2. Energy consumption and data recording
Energy consumption data for the past two years was extracted from BPC to assess the actual EPI of
the building as presented in Table 13.
Table 13: Energy Performance Index: Commercial building from 2011-12 to 2012-13
Parameters 2011-12 2012-13
Units consumed (kWh/year) 1999 1999
Builtup area (Sq.m) 1586.3 1586.3
EPI Index (kWh/Sq.m/year) 117.3 116.5
Electrical load profiling was recorded for 24 hours using krykard three phase power analyzer. The
total load during the day of recording and total electricity consumption is presented in Figure 13.
Figure 13:Active power and electricity consumption profile of commercial building
0
10
20
30
40
50
60
70
80
90
7:2
0:0
0 P
M
8:3
0:0
0 P
M
9:4
0:0
0 P
M
10:5
0:0
0 P
M
12:0
0:0
0 A
M
1:10
:00
AM
2
:20
:00
AM
3
:30
:00
AM
4
:40
:00
AM
5
:50
:00
AM
7
:00
:00
AM
8
:10
:00
AM
9
:20
:00
AM
10
:30
:00
AM
11
:40
:00
AM
12
:50
:00
PM
2
:00
:00
PM
3
:10
:00
PM
4
:20
:00
PM
5
:30
:00
PM
6
:40
:00
PM
Active power profile (kW)
Kilowatts
0
200
400
600
800
1000
1200
7:2
0:0
0 P
M
8:4
0:0
0 P
M
10:0
0:0
0 P
M
11:2
0:0
0 P
M
12:4
0:0
0 A
M
2:0
0:0
0 A
M
3:2
0:0
0 A
M
4:4
0:0
0 A
M
6:0
0:0
0 A
M
7:2
0:0
0 A
M
8:4
0:0
0 A
M
10:0
0:0
0 A
M
11:2
0:0
0 A
M
12:4
0:0
0 P
M
2:0
0:0
0 P
M
3:2
0:0
0 P
M
4:4
0:0
0 P
M
6:0
0:0
0 P
M
Electricity consumption profile (kWh)
kWh
Department of Renewable Energy, Ministry of Economic Affairs, Royal Government of Bhutan
Energy Efficiency Study in Building Sector
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Total electricity consumption (kWh) of the building measured during 24 hours is
1,008 kWh.
2.2.3. Construction practices at the building
The energy audit included capturing construction practices as well as components of the building envelope (exterior shell).The components of a building envelope include the exterior walls, foundation, and the roof. Energy used within the building is dependent on the materials used and the construction practices adopted. The details of construction material used at the building are presented at Table 14.
Table 14: Construction Practices: Institutional building
Parameters Material Insulation Age Condition U Value
(W/m2K)
Exterior
walls
(Reception &
restaurant)
Solid brick (305 mm,
plaster)
No 6 Good 1.64 to 2.11
Inner walls
(Reception &
restaurant)
Wooden No 6 Good 0.28 to 0.6
Room walls Combination of wood
boards, glass wool and
plaster
Yes 6 Good 0.82
Ceiling Combination of wood
boards, glass wool and
plaster
Yes 6 Good 2.92
Roof GI sheets / wooden
truss
No 6 Good 0.9 to 1
Building fenestration was also captured during the audit. Highlights of the fenestration are as follows:
Fenestration at the building is six years old
The building has all single pane glass with either an aluminium or wooden frame
All window's were provided with black films and curtains
2.2.4. Connected load at the building Connected load of the building was captured
during the energy audit to assess the percentage
of different energy consuming loads installed at
the building. The list of different electricity
consuming sections and their percentage load
distribution are provided at Figure 14 and Table
15.
Figure 14: Percentage load distribution at commercial building
7% 2%
35%
40%
16%
Electrical load distribution (kW)
Lighting
Fans
Heating
Office & other general equipments
Kitchen & laundry equipments
Department of Renewable Energy, Ministry of Economic Affairs, Royal Government of Bhutan
Energy Efficiency Study in Building Sector
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Table 15: Electricity consuming sections at commercial building
S. No. Electricity consuming sections Total Load (kW)
1 Office & other general equipments 50.3
2 Only heating (room heaters) 44
3 Lighting 9.417
4 Kitchen & laundry 19.59
5 Fans 2.76
Total 126.067
Some observations of the energy audit of the building are provided below:
Geyser is the major load under office and general equipment category with a 40% share. None of the geysers were star rated.
Room heaters used were of radiator type and were the second major load with 35% share. They consumed 25% more power than the rated value.
Among the lighting load nearly 69% comprised of Incandescent and T-12.
Ceiling fans used at resort were rated for 70 W.
It can be thus established that, lightings and fans installed are not that efficient. Introduction of energy efficient lightings and fans can significantly reduce the energy consumption at the premises. Therefore recommendations were suggested and cost benefit analysis of different options was done to identify most cost effective options.
Department of Renewable Energy, Ministry of Economic Affairs, Royal Government of Bhutan
Energy Efficiency Study in Building Sector
PwC 25
2.2.5. Recommendations Table 16: Recommendations for the commercial building
Energy conservation measure (ECM)
Existing
connecte
d load
(kW)
Reduced
connected
load (kW) post
ECM
implementatio
n
Energy
savings
(kWh/year
)
Annua
l GHG
saving
s
(tones)
Investmen
t required
(Nu)
Simple
payback
(months
)
Discounte
d payback
(DPB)
(months)
IRR
Categor
y based
on DPB
Priorit
y
Replacing incandescent bulbs (25 W) with LEDs (3W)
3.75 0.45 16863 14.33 47250 15.6 23.5 59.7 % Medium term
Medium
Replacing incandescent bulbs (25 W) with CFLs (5W)
3.75 0.75 15330 13.03 14175 5.2 8 63.6 % Short term
High
Replacing T12 tube lights having magnetic ballast (54 W) with LED based tube lights (18 W)
2.7 0.9 9198 7.81 105000 64 Not feasible 11 % Long term
Low
Replacing T12 tube lights having magnetic ballast (54 W) with T5 having electronic ballast (28 W)
2.7 1.4 6643 5.64 21000 17.6 More than the life of equipment
6.33 % Medium term
Medium
Replacing magnetic type ballasts in FTLs (14 W) with electronic type (1 W)
0.7 0.05 3321 1.52 10500 17.6 26.6 27.7 % Medium term
Medium
Replacing 70 W ceiling fan with energy efficient 50 W fan
1.61 1.15 966 0.82 41055 237 More than equipment life
Not feasible
Long term
Low
From all the options discussed above, option 1, 2 and 5 in lighting gives best replacement rationale having positive IRR. As the
electricity cost in Bhutan is very less as compared to other developing or developed countries, these options do not reflect very
attractive in terms of monetary payback, however their energy consumption reduction potential remains very high.
Department of Renewable Energy, Ministry of Economic Affairs, Royal Government of Bhutan
Energy Efficiency Study in Building Sector
PwC 26
2.3. Case study 3- Domestic household at Bumthang
The components of energy audit captured at domestic - urban and rural households are discussed next
in brief:
2.3.1. Backdrop
Table 17: Domestic household details
Details
Urban house – U1
Owner name: Mr. Kinley Tenzin
Contact No.: 975 77383402
Built-up area: 93.5 meter2
Building sections: 3 bedroom, 1 living
room, 1 kitchen and 2 toilets
Year of establishment: 2003
Primary source of energy: Electricity
Other source of energy: Wood for space
heating and LPG for cooking food
Sanctioned load: 20 kW
Consumer (CA No.): 30043995
Meter No.: 374 (single phase)
Urban house – U2
Owner name: Mr. Phuntsho
Contact No.: 975 17689875
Built-up area: 106.3 meter2
Building sections: 2 bedroom, 1 living
room, 1 prayer room, 1 kitchen and 1 toilet
Year of establishment: 1998
Primary source of energy: Electricity
Other source of energy: Wood for space
heating and LPG for cooking food
Sanctioned load: 12 kW
Consumer (CA No.): 40024929
Meter No.: 3584 (single phase)
Details
Rural house – R1
Owner name: Mr. Thinley (Ugyen
Lhadon)
Contact No.: 975 17748298
Built-up area: 83.1 meter2
Building sections: 2 bedroom, 1 kitchen
and 1 toilet
Year of establishment: 2007
Primary source of energy: Electricity
Other source of energy: Wood for space
heating and LPG for cooking food
Sanctioned load: 5 kW
Consumer (CA No.): 30091030
Meter No.: 606446 (single phase)
Rural house – R2
Owner name: Mr. Lodey
Contact No.: 975 17593129
Built-up area: 83.2 meter2
Building sections: 2 bedroom, 1 kitchen
and 1 toilet
Year of establishment: 2007
Primary source of energy: Electricity
Other source of energy: Wood for space
heating and LPG for cooking food
Sanctioned load: 15 kW
Consumer (CA No.): 30044701
Meter No.: 4100 (single phase)
2.3.2. Energy consumption data
Energy consumption data for past two years was extracted from BPC Dzongkhag office at Bumthang.
The energy consumption details of urban and rural homes are presented in Table 18.
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Energy Efficiency Study in Building Sector
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Table 18: Energy consumption details: Urban and Rural households
Urban 1 Urban 2
Parameters 2011-12 2012-13 2011-12 2012-13
Units consumed (kWh/year) 779 859 2901 1648
Builtup area (Sq.m) 93.5 93.5 106.3 106.3
Rural 1 Rural 2
Parameters 2011-12 2012-13 2011-12 2012-13
Units consumed (kWh/year) NA 449 1643 3389
Builtup area (Sq.m) 83.1 83.1 83.2 83.2
2.3.3. Construction practices at the households
The energy audit included capturing construction practices as well as components of the household
envelope (exterior shell).The components of a envelope include the exterior walls, foundation, and the
roof. Energy use is dependent on the materials used and the construction practices adopted. The
details of construction material used are presented at Table 19.
Table 19: Details of different household building envelope
Household Parameters Material Additional
insulation
material
Condition U Value
(W/m2K)
U1 Exterior walls Ekra wall (cement & timber
mat combination)
No Good Approx 2.11
Inner walls Wooden wall No Good 0.28 to 0.6
Ceiling Combination of wood and
mud/cement
No Good 0.3 to 0.7
Roof GI sheets/wooden truss (No
Insulation)
No Good 0.9 to 1
U2 Exterior walls Ekra wall (cement and timber mat combination)
No Average Approx 2.11
Inner walls Wooden wall No Good 0.28 to 0.6
Ceiling Combination of wood and mud/cement
No Good 0.3 to 0.7
Roof GI sheets/wooden truss (No Insulation)
No Good 0.9 to 1
R1 Exterior walls Brick wall No Average Approx 2.11
Inner walls Wooden wall No Good 0.28 to 0.6
Ceiling Combination of wood and mud/cement
No Good 0.3 to 0.7
R2 Exterior walls Ekra wall (cement and timber mat combination)
No Good Approx 2.11
Inner walls Wooden wall 0.28 to 0.6
Ceiling Combination of wood and mud/cement
No Good 0.3 to 0.7
Roof GI sheets/wooden truss (No Insulation)
No Good 0.9 to 1
Department of Renewable Energy, Ministry of Economic Affairs, Royal Government of Bhutan
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Fenestration was also captured during the audit. Highlights of the fenestration are as follows:
Fenestration were 10- 15 years old for urban homes and nearly 6 years for rural homes
All the household has single pane glass with a wooden frame
All window's were provided with curtains
2.3.4. Connected load at urban and rural households
Connected load of the urban and rural households were captured during the energy audit to assess the
percentage of different energy consuming loads installed at the building. The percentage load
distribution for urban and rural households is presented at Figure 15.
Figure 15:Percentage load distribution at urban and rural households
Some of the observations of the energy audit are provided below:
Among the lighting load, usage of T12 and incandescent is much higher than CFLs.
Urban households were using geysers and none of the geysers were star rated.
Room heaters were found only in urban households. The heaters were drawing about 25% more power than the rated value.
Every household has television. The usage of conventional CRT televisions is more. The consumption of CRT is much higher than LCD/LED.
5%
39%
27%
29%
Urban house 1 (U1), 12.2 kW
6%
25%
29%
40%
Urban house 2 (U2), 9.42 kW
12% 6%
82%
Rural house 1 (R1), 1.84 kW
6% 5%
89%
Rural house 2 (R2), 2.8 kW
Electrical load distribution (kW)
Department of Renewable Energy, Ministry of Economic Affairs, Royal Government of Bhutan
Energy Efficiency Study in Building Sector
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During the survey, the household occupants were questioned to know their awareness and interest
related to energy efficiency. The occupants had a constructive opinion towards energy efficiency but
they were not fully aware about different ways to save energy. Based on the survey, there is a need to
aware residential consumers towards latest developments & initiatives in the energy efficiency sector.
This will provide an opportunity to consumers for saving energy through different options.
In the years to come, it is expected that the consumption will increase as the occupant’s living
standards and luxury demands go up. With the increase in electricity prices there will have a major
impact on the households. Hence, efficient use of electricity is the need of the hour.
Just because it is rational for consumers to invest in all conservation opportunities with a considerable
payback does not mean that consumers know what those opportunities are. While providing
homeowners with information about what to do is necessary, care must be taken in how that
information is presented. Practical experience shows that presenting too many choices can actually
increase the likelihood that someone won’t choose at all.
Considerable awareness on energy efficiency measures plays an important role in achievement of
desired results. The government of Bhutan and all associated stakeholders shall initiate efforts to enhance the capacity and know-how of local people towards the benefits associated with energy efficiency improvements. It will not only add to uptake of energy conservation but will also make the economy more advanced in terms of availability of material and equipments. Based on the connected load observations it can be established that, introduction of energy efficient lightings can significantly reduce the energy consumption at the households. Therefore calculations were undertaken to assess the energy saving if replacement is considered at the households.
2.3.5. Firewood usage at urban and rural households
Firewood is a common source used for space heating in Bhutan. A bukhari is a traditional space
heater (firewood-burning stove) used in Bhutan Table 20. Snapshot of traditional bukhari system is
presented at Figure 16.
Table 20: Details of firewood consumption at households
Household Annual consumption (tonnes) Annual expenditure (Nu.)
U1 5 5700
U2 5.5 6000
R1 2.5 800
R2 4.5 2050
Figure 16: Traditional bukhari system
2.3.5.1. Key observations
During the energy audit, the composition of flue gases
releasing from the exhaust stack of bukhari was
captured. The excess air levels in the flue gas were on
the higher side which signifies that the overall efficiency
of the system is low. The overall efficiency generally
ranges between 10 to 20 percent only. This is due to the
fact that the stoves generally have lot of heat loss due to
inefficient design & local construction.
Department of Renewable Energy, Ministry of Economic Affairs, Royal Government of Bhutan
Energy Efficiency Study in Building Sector
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2.3.5.2. Energy efficiency opportunities
• To get the most out of firewood, it is important to properly dry (season) the wood.
Well-seasoned firewood will start easily & burn bright with little smoke.
• The conventional stoves (locally made) burn wood inefficiently, which wastes firewood,
pollutes the air and leaving dust particles. Newer stoves can reduce smoke and dust, as
well as cut heating expenses. The Unites States Environment Protection Agency (US EPA)
has initiated certification of wood stoves so as to make it energy efficient and safer for
home usage.
As per the US EPA program there can be approximately 50% more efficient operation
of wood stoves and can limit the use of firewood to one-third for the same heat. DRE is
already undertaking a program for the Bukhari system improvement in Bhutan.
2.3.6. Recommendations
Table 21: Recommendations for domestic households
Household Suggested ECMs measures
Payback period (months)
Type of category
Level of priority
Annual electricity saving (kwh)
Annual GHG emission saving (tonnes)
U1
1. Replacement of T12 tube lights with T5, and,
2. Replacement of incandescent bulbs with CFLs
Combined payback for both ECMs is 24 months.
Separately it is 50 months for ECM1 and 12 months for ECM2.
Medium term
High 706 0.6
3. Replacing incandescent bulbs with LED bulbs
30 Medium term
Medium 518 0.44
Use of thermostat in electric room heaters
27 Medium term
Medium 648 0.55
Replacement of T12 tube lights with LED lights
172 Long-term
Low 394 0.33
U2
1. Replacement of T12 tube lights with T5, and,
2. Replacement of incandescent bulbs with CFLs
Combined payback for both ECMs is 29 months.
Separately it is 44 months for ECM1 and 8 months for ECM2.
Medium term
High 761 0.65
3. Replacing incandescent bulbs with LED bulbs
30 Medium term
Medium 388 0.33
Use of thermostat in electric room heaters
27 Medium term
Medium 325 0.28
Replacement of T12 tube lights with LED lights
157 Long-term
Low 605 0.53
R1
Replacement of incandescent bulbs with CFLs
5 Short-term
High 408 0.34
Replacing incandescent bulbs with LED bulbs
41 Long term
Low 417 0.35
R2 Replacement of incandescent bulbs with
8 Short-term
High 108 0.09
Department of Renewable Energy, Ministry of Economic Affairs, Royal Government of Bhutan
Energy Efficiency Study in Building Sector
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Household Suggested ECMs measures
Payback period (months)
Type of category
Level of priority
Annual electricity saving (kwh)
Annual GHG emission saving (tonnes)
CFLs
Replacing incandescent bulbs with LED bulbs
30 Medium term
Medium 129 0.11
From all the ECMs discussed, the options that give the best replacement rationale have
been highlighted with high priority. Considering the high priority ECMs the energy
consumption of households can be reduced and there will be cost savings in following
manner.
Urban house 1 – 706 electricity units equivalent to Nu 1313 / annum.
Urban house 2 – 761 electricity units equivalent to Nu 1415 / annum.
Rural house 1 – 408 electricity units equivalent to Nu 759 / annum.
Rural house 2 – 108 electricity units equivalent to Nu 200 / annum.
Department of Renewable Energy, Ministry of Economic Affairs, Royal Government of Bhutan
Energy Efficiency Study in Building Sector
PwC 32
2.4. Summary of the observations of practices
Detailed energy audits of different buildings was very helpful in assessing the end use energy
consumption . The summary of section wise observations and status of energy efficiency
options is presented below:
2.4.1. Lighting
Primarily the lighting load in most buildings comprises of three types of lighting lamps. These
are T12 tube lights having magnetic ballast, incandescent bulbs and compact
fluorescent lamps (CFLs).
In most buildings, majority of the lighting load is through connections of T-12 and
incandescent bulbs. In many buildings the load pertaining to these lamps is higher than 60%
of the total lighting load.
Although CFL and energy efficient T5 tubes are available in the local markets, the usage of T-
12 tube lights and incandescent bulbs is dominant.
During the energy audit, it was established that sufficient daylight was available in most of the
buildings and can be utilized without turning-on any light point. However, it was also
observed that most of the light points were kept in the switched-on mode during the day time.
The electricity consumption can be reduced by merely switching off extra lights as the actual
lux level was far above the recommended levels. This can be achieved through developing
efficient lighting design and initiating energy efficiency awareness plans.
2.4.2. Heating Ventilation & Air Conditioning (HVAC)
As such an integrated HVAC system is not very common in the commercial and institutional
buildings at Bhutan. This can be attributed to the climatic conditions, as the requirement for
heating load is dominant over the cooling requirement.
However, it is expected that with the growth of tourism and other commercial sectors in fast
developing economy like Bhutan the usage/demand for HVAC is set to rise in near future. But
the overall observation is that HVAC (cooling) is not the major load in overall consumption.
The energy conservation building code for buildings in Bhutan can facilitate various practices
and measures that will be helpful in establishment of energy efficient HVAC operation.
2.4.3. Air conditioning
The load pertaining to air conditioners is dominant in regions falling under the sub-tropical
climate zone of Bhutan such as Phuentsholing. The air conditioners used were either BEE’s 2
star or no star rated.
High energy efficient star rated ACs are available in the Bhutanese market and there exists a
significant saving potential if replacement of existing with efficient ones is considered.
2.4.4. Space heating (through electric room heaters)
Electric room heaters (radiator type mostly) hold a significant percentage (around 30%-35%)
in the total connected load of most buildings. The usage of electric heaters was more
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prominent in regions falling under the mid-montana and alpine climatic zones (cold
climates).
Moreover, it was observed that these electric heaters consume nearly 20-25% more power
than the rated value. Regulatory control over the quality check of heaters is important to
control excess power consumption.
2.4.5. Fans
Ceiling fan was the major load among the fan categories. Most ceiling fans were rated for 70W
and none of them were star rated. These loads were mostly available in regions falling under
subtropical zone.
2.4.6. Office and other general equipments
Geysers contribute around 60-70% load under the general equipments category in most
buildings. None of the geysers were star rated.
The load pertaining to geysers is quite high and therefore replacement of the existing geysers
with star rated ones has the potential to bring significant energy savings through reduction in
standby losses.
Electric rice cookers having 700 W to 1500 W rated electricity consumption were one of the
most common appliances found in almost every building. The refrigerators are the next most
common appliance found in every facility.
2.4.7. Firewood usage
In addition to room heaters, the households also use firewood based Bukhari system for space
heating. Bukhari is used for burning firewood. It is a kind of wood stove which is most common in
entire Bhutan. The firewood is usually sourced from hardwoods and softwoods. The usage of firewood
is dominant in regions falling under alpine and mid-montana climatic zones such as Bumthang,
Trongsa, Thimpu etc.
On an average an urban household consumes 5 tonnes of firewood in a year and rural
household consumes 2.5 tonnes in a year.
The Bukhari (wood burning stove) were mostly locally made and efficiency of the system
generally remains between 10-20%.
2.4.8. Construction practices
Type of building material, fenestration material and insulation used were captured and it was found
that most of the buildings were without any insulation. The construction practices are discussed in
greater details in next sections. .
T
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The need for standardization of construction practices and regulating the measures for
lighting, HVAC, heating system and other energy efficiency practices in the building
encourages the need for development of a set of guidelines or code for efficient use of
energy inside the buildings in Bhutan, without hindering the traditional architecture.
Thus there is a need for energy standards and codes for buildings in Bhutan to
benchmark different energy consuming practices being followed.
The field observations chapters. obtained in this study has been used for development
of Bhutan energy efficiency code (BEEC). The process steps undertaken to develop code
document is presented in next
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3. Status of Building Regulations in Bhutan – Standards and Bodies
All BEECs refer to standards pertaining to construction, materials, testing methods that set minimum
benchmarks for the the country to follow. The country, over time, enters cycles of updates involving
various stakeholders of the sector, here specifically it is the building design and the construction
sector.
In Bhutan, the Ministry of Works and Human Settlements, the Ministry of Statistics, Local
Departments of Works, and Roads, Department of Urban Development and Housing, Bureau of
Standards and Quality Control and numerous other Central and Local Stautory, Ordinnance and
Statute forming and/ or Implementing agencies will have a key role to determine the referenced
Standards and their legal frameworks for the adoption of code (BEEC)formulation.
In this context various docments were referred to, in addition to discussions with the client. We follow
this with a synopsis of our understanding as to how the various Standards referenced extensively in
Bhutan will be impacted or will impact in return with the adoption of a BEEC.
In 2003 the Bhutan Building Rules – 2002 (BBR-2002) came into effect andare applicable for all
urban areas superseding all other rules on building regulations to facilitate and regulate a functional
and safe building construction practice, to promote a healthy living environment, to encourage
professional approach to building design and construction, to preserve and promote traditional
architecture and to promote awareness on basic minimum design standards and procedures.
The building design and construction is authorized by the ‘Competent Authority’ defined in the
Municipal Act, 1999 which is in line with how it is usually experienced in other parts of the world.
Various words, for e.g. ‘Achitect’, ‘Engineer’, ‘Commercial Building’, ‘Building Inspector’,
‘Implementing Authority’ amongst others, clearly illustrate that the building construction industry is a
well developed and professional activity that is administered locally by the Municipal Authority.
The development process for all new construction, addition and alteration including major
renovations follows a development plan in Bhutan. A project proponent must follow a permit
application process seeking permission to build with a payment of the permit fee. It is the
responsibility of the implementing agency to ensure that the applicant builds as per the prevalent
architectural guidelines, controls and minimum standards laid out by the municipal authorities or
others. A building inspector must check drawings and on field observations to ensure compliance.
After field inspection the implementing agency also issues a fit or a not fit for occupancy certificate.
The permit to build may be cancelled, revoked and the implementing agency has the authority to stop
construction in case of unauthorized construction or in case of misuse of land. And, as a last resort the
unauthorized structure may need to be demolished. The permit process and enforcement mechanism
will accommodate BEEC provisions within the realm of existing architectural control and bye-laws
administered locally by the implementing agency.
Materials used must comply with minimum standards as specified in the IS codes, PWD specifications
and other relevant codes of practice.
Architectural controls pertaining to light and ventilation needs in a ‘habitable space’ are currently but
partly addressed in BBR-2002 (as a function of the space floor area). The BEEC will have an impact
on these requirements which will need to be revised in due course.
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Likewise, introduction of the Bhutan BEEC is likely to influence the architectural and structural
design standards referenced in BBR-2002 (below) which will need to be revised and updated. These
influences are expected to affect envelope insulation and air-tightedness of Bhutenese buildings
thereby garnering a new generation of buildings that would promote and cherishes local architecture
while improve EE and reduce the environmental and carbon footprint.
Analysis of the structure (building)
PWD structural design standards 1997
IS 1893 - 1984: Criteria for earthquake resistant design of structures
IS 456 – Code of practice for plain and reinforced concrete
IS 875 –1987: Code of practice for Design loads (other than earthquake)
NUDC/007/1985 – Timber Roof Trusses
NUDC/002/1985 – Manual for Timber Engineering Design
Design of the structure (buildings)
PWD structural design standards 1997
IS 4326 – Earthquake resistant design & construction of building
IS 456 – Code of practice for plain and reinforced concrete
NUDC/007/1985 – Timber Roof Trusses
NUDC/002/1985 – Manual for Timber Engineering Design
IS 800 – Design of steel structures
IS 806 – Design of Tubular Truss
IS 1904-1978: Code of practice for structural safety of buildings (Shallow foundation)
Detailing of the structure (buildings)
PWD structural design standards 1997
IS 13920 –1993: Ductile detailing of concrete structures subjected to seismic forces
IS 4326 – Earthquake resistant design & construction of building
IS 456 – Code of practice for plain and reinforced concrete
NUDC/007/1985 – Timber Roof Trusses
NUDC/002/1985 – Manual for Timber Engineering Design
IS 800 – Design of steel structures
IS 806 – Design of Tubular Truss
Introduction of a Bhutan BEEC influences on electrical design – for e.g. tandem wiring, sensors,
motor ratings, transformer efficiencies, high efficiency HVAC equipment, allowances for voltage
efficiency drop etc. in the local bye-laws and standards referenced in BBR-2002 will need to be
revised. Similarly standards addressing artificial lighting and mechanical ventilation BTS-012,
Electrical Installations Control BTS-010, may need a review and subsequent revision upon the
adoption of a BEEC. Finally, voluntary and best practise based policy initiatives for e.g. the Green
Building Guidelines 2013 propounded by the MoWHS will also refer tothe minimum performance
benchmarks of code components after the respective update of various Standards.
Standards addressing safety, for e.g. Fire Safety BTS-014 may take priority over BEEC influences.
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4. International review programs on BEECs 4
Building energy efficiency codes set standard requirements for how energy-efficient a building will be.
Standards may vary slightly between countries in several respects including the extent of their
coverage, the specific requirements, means of attaining compliance and the enforcement system.
Some BEEC from around the world were taken up as case studies keeping in mind the context of
Bhutan.
Parallels were drawn in terms of the country being a developing nation or the climate being similar to
Bhutan. The countries that were studied were – India, USA, Mexico, China, Egypt
The parameters studied in each of these cases were as follows:
Energy savings potential
Standards referenced
Components covered by the code (scope)
Climatic zones
Compliance structure
Relevance to Bhutan
Table 22: International review of different building energy efficiency programs
Type of buildings addressed
Building energy consumption as % of total energy consumption
Standards Referenced
Components Covered
Enforcement Compliance Structure5,6
Relevance to Bhutan
India Commercial 40% ASHRAE/ ASTM, IS, ISO
All (Envelope, Lighting, Service Hot Water and Electrical Power)*
Enforced by local jurisdiction
Mandatory in some states
Prescriptive
trade-off
Performance based
Developing nation
Warm humid climate zone similar to Bhutan
Challenges in building industry similar to Bhutan
USA Commercial 40% ASHRAE/ ASTM
All* Enforced by local jurisdictions through building permit process
Prescriptive
Trade-off
Performance based
Very Cold climate zone 7 similar to Bhutan
4 World Bank Working Paper No. 204, Mainstreaming Building Energy Efficiency Codes in Developing Countries – Global Experiences and Lessons from early adopters, Feng Liu, Anke S Meyer, John F Hogan 5 Prescriptive method of compliance offers a simple but rigid implementation methodology for meeting minimum standard requirements for each code component covered. The Trade-off approach 6 Performance method of compliance offers a flexible but complex implementation methodology for meeting minimum standard requirements for each code component covered
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Mandatory
China Commercial** 30% ASHRAE/ local standards
Not covered – Lighting, Service Hot water, Electrical power
Enforced by local / provincial jurisdictions
mandatory
Prescriptive
Trade-off
Except for region being similar, not much similarity
Mexico
Commercial 20% Mostly local standards and ASHRAE
All Enforced by local jurisdictions
Mandatory
Prescriptive Performance
based
Developing nation
Similar Latitude
Egypt Commercial** 23% ASHRAE/ local standards
All Enforced by local jurisdictions
Mandatory
Prescriptive
Performance based
Developing nation
*All – Envelope, Lighting HVAC, Service Hot water, Electrical power ** Residential is also addressed
Typical challenges faced by developing nations towards implementation and success of
the building energy codes
Cost effective energy efficiency improvements in buildings by definition are financially attractive,
usually paying for themselves within a few years. They also generate multiple co benefits, ranging
from improved comfort and health for the occupants to reduced air pollution for the general
public.
Global experiences indicate that the implementation of building energy codes is likely to have more
success in countries and localities where the construction sector is well managed in terms of
government oversight, the building supply chain is well established, the market for commercially
produced buildings is well developed, and there is broad and firm political commitment to improving
energy efficiency. Weaknesses in these areas are often the main challenges in developing countries
when they embark on efforts to implement building energy codes. Some of the key challenges faced by
the developing world towards implementation of building energy codes are as follows:
Lack of information about energy use and efficiency in commercial buildings.
Underdeveloped materials and components market for compliance, including related testing and certification capabilities.
Largely unskilled workforce that is unaware also uneducated in building energy efficiency aspects.
Subsidized residential electricity prices.
Limited ability to internalize incremental cost of EE technologies due to low income levels. With tight budget constraints for both governments and private citizens, a balanced tradeoffs is needed between more housing and more energy efficient housing. For low income countries, the priority is to maximize the floor area for a given amount of housing investment.
Absence of an Effective Government Oversight System for Building Construction - Large amount of informal building construction is outside of government oversight. Also, a robust building permit and inspection system provides a good basis for incorporating supervision arrangements for building energy codes. But its effectiveness often depends on the transparency and strength of the general governance framework, which are often weak in developing countries.
Last but not the least, Implementing modern measures to reduce/minimize building heating, cooling, and lighting loads requires a host of new design skills and approaches, new or improved materials/components and construction techniques, as well as additional supervision and inspections, compared with the prevailing commercial construction
Department of Renewable Energy, Ministry of Economic Affairs, Royal Government of Bhutan
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practices found in many developing countries. Standards for rating and certifying these new energy efficient products will need to be established so that there is a level playing field for manufacturers to compete and take credit for their energy efficiency advances, and so that developers and designers can have confidence in the claims being made for energy efficient products. Multidimensional efforts will be needed in educating new generations of architects and engineers, training construction workers, supervisors and inspectors, and ensuring the availability and quality of new or improved materials and components.
Split incentives and principal agent problems. Split incentives prevent basing investment decisions on life cycle costs and, consequently, the realization of the benefits of energy efficiency investments. This is primarily since all investment decisions are made by developers and investors, not by those who will occupy the building later and be responsible for paying the energy bills.
Risk perception due to lack of confidence in performance of new technologies. Lack of information and knowledge. Information about energy efficiency options is often incomplete, unavailable, expensive, and/or difficult to obtain or trust. Even developers, design professionals, and contractors are not always aware of the energy efficiency technologies available
Low relevance of relatively small future costs of heating cooling and lighting - future costs of heating, cooling, and lighting services in buildings are a relatively unimportant factor, since they generally are fairly small sums on a monthly basis.
Bhutan is likely to face most of these challenges of capacity and awareness and the absence of a robust
and informed governance process. It will be in our interest therefore to develop and implement a step
by step process for code implementation that is rolled out over time in a manner such that the
building supply chain is simultaneously made ready to receive the code.
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5. Climate Zones determination for Bhutan
Bhutan's climate is as varied as its altitudes and, like most of Asia, is affected by monsoons. Western
Bhutan is particularly affected by monsoons that bring between 60 to 90 percent of the region's
rainfall. The climate is humid and subtropical in the southern plains and foothills, temperate in the
inner Himalayan valleys of the southern and central regions, and cold in the north, with year-round
snow on the main Himalayan summits.
Figure 17: Climate zone for Bhutan : Geographic regions overlaid on the administrative regions of Bhutan
Temperatures vary according to elevation. Temperatures in Thimphu, located at 2,200 meters above
sea level in west-central Bhutan, range from approximately 15°C to 26°C during the monsoon season
of June through September but drop to between about -4°C and 16°C in January (see table 22,
Appendix). Most of the central portion of the country experiences a cool, temperate climate year-
round. In the south, a hot, humid climate helps maintain a fairly even temperature range of between
15°C and 30°C year-round, although temperatures sometimes reach 40°C in the valleys during the
summer.
Further, Bhutan climate and weather was studied along with the Koppen climate classification system.
Similar climate zones to those in Bhutan were considered in detail. This exercise resulted in
determining climate zones referenced elsewhere in other BEECs which was relevant for the Bhutan
context, and therefore the Bhutan BEEC.
While the Köppen classification system doesn't consider temperature extremes,
average cloud cover, number of days with sunshine, or wind into account, it's a good
representation of our earth's climate. With only 24 different sub-classifications,
grouped into the six categories, the system is easy to comprehend.7 The Köppen and its
derivative systems are simply a guide to the general climate of the regions of the planet,
the borders do not represent instantaneous shifts in climate but are merely transition
zones where climate, and especially weather, can fluctuate.8
1 Rosenberg, M., http://geography.about.com/od/physicalgeography/a/koppen.htm; December, 2013 8 Rosenberg, M., http://geography.about.com/od/physicalgeography/a/koppen.htm; December, 2013
Department of Renewable Energy, Ministry of Economic Affairs, Royal Government of Bhutan
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It was concluded that Bhutan has four distinct (Köppen-Geiger, 2006) climate classification types
within its administrative boundaries. These are:
ET (Tundra),
Dwd/ Dwc (Snow climate, dry winter, Extremely Continental or Cool Summer, Cold Winter)
Cwb (Warm Temperate with Dry Winter, and Warm Summer)
Cwa (Warm Temperate with Dry Winter, and Hot Summer)
For specific applicability to the Bhutan BEEC, a suitable (reference) climatic zone map defining the
climatic zone boundaries (Standard) could not be found. Such an exercise is essential for the code.
However, based on the findings it was determined that the three main geographic regions will have a
strong bearing on the determination of the (yet to be decided) boundary for the applicable climatic
zones of Bhutan BEEC. Therefore following is deduced for Bhutan:
Table 23: Bhutan specific Köppen-Geiger climate classification
Bhutan specific Köppen-Geiger climate classification
Climate zones characteristic in view of the three primary geographical regions (Alpine, Mid-Montana and Sub-tropical)
Determination for Referenced Standard for the Building Envelope Chapter for Bhutan BEEC
ET (Tundra), Very cold ASHRAE/ ANSI 90.1-2007, Zone 7
Dwd/ Dwc (snow climate with dry winter, extremely continental or cool summer, cold winter)
Cwb (warm temperate with dry winter, and warm summer)
Cold ECBC 2007, Cold
Cwa (warm temperate with dry winter, and warm summer)
Warm and humid ECBC 2007, warm and humid
Department of Renewable Energy, Ministry of Economic Affairs, Royal Government of Bhutan
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6. Construction Practices
6.1. Integration of modern construction designs with traditional features
With the unprecedented growth in construction techniques and materials, a day to day improvement is
required for achieving a balanced development. According to the climatic zones specified in previous chapter
there are many construction practices to be considered:-
6.1.1. Orientation and shape of the building
Bhutanese buildings adhere to the contemporary principles of sustainability, and are oriented in such a way
so as to reduce heat losses and maximize passive solar gain. For instance9, within Bhutanese villages, 'houses
and trees are arranged in such a way as to provide each other with maximum wind shelter'.
It is also interesting to note the use of thermal mass and wind sheltering techniques to create ‘outdoor hot-
zones10’ both between buildings within a cluster, and also around these building by means of a 2m high
boundary-type wall11.
12 Figure 18: Traditional building in
Bhutan (depicting a rabsel on the side of
the wind direction)
Individual buildings generally follow a typical layout:-firstly there is a wall made up of rammed mud which
runs along the back. This wall generally faces the north direction. This section of the building has the largest
openings. In order to allow the maximum percolation of light, the most prominent rooms are located in the
area of the building13.
“A long experience with earthquakes as well as tremors has made the Bhutanese people careful14” and hence
along with adherence to traditional architectural principles, buildings in Bhutan incorporate many features
characteristic of a good seismic design. They are invariably symmetric in plan with symmetric openings, an
important precautionary measure in seismic design1516.
Table 24: Different building materials and their attributes - Examples from Bhutan
9 DoWHR, 1993:188 10 DoWHR, 1993:227 11 DoWHR, 1993:205 12 Source: - http://richardarunachala.wordpress.com/2013/10/03/bhutan-traditional-arts-and-the-tashichhoe-dzong-
in-thimphu/ 13 DoWHR, 1993:195 14 DoWHR, 1993:201 15 Arya, 2007:101 16 House plans are also generally square or rectangular, as advocated by Minke (2001:9)
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Materials Attributes Building element
Field study Conclusion
Boulders, rocks, stones
Provide insulation
Cost effective
Thermal mass
Locally available
Good life span
Foundation
Plinth
Walls
Roofs
Most of the traditional foundations were huge due to load bearing construction.
17 Stone foundation
18
With some advancement stones should be used for future construction.
Soil or mud Good thermal mass
Cost effective
Can give insulation
Locally available
Life span (depends)
Walls
Roof(internally)
Several heritage buildings are made from rammed earth.
Due to recent earthquakes, these buildings were not in a good condition.
In certain places, mud was used in the roof, particularly in Dzongs.
19
20
It must be retained if proper skilled sets are provided.
Timber or wood
Thermal mass
Cost effective
Provides insulation
Locally available
Good life span
Internal walls
Rabsel
Fenestrations
Roofs
Cornices
Stairs
Internal walls of rural houses and resorts used wood. However, resorts an added insulation of glass wool.
Many of the hotels, urban and rural houses preferred wooden windows of different shapes and sizes according to their requirements.
Many resorts and urban houses incorporated wooden roofs. However, resorts used extra insulation.
21 22
23
Since it is not a renewable material, and forests are affected, some alternative materials need to be taken into consideration
Bamboo Cost effective
Locally available
Good life span
Frame structure
Wall
Roof
Stairs
An urban house demonstrated a proper construction of framed structure with bamboo.
Upper stories of hotels and urban as well as rural houses constructed an Ekra wall with no additional insulation.
24 A 100m2 building in Tingtibi, Zhemgang district, Designed and constructed by INBAR, the Ministry of Agriculture and Forestry of Bhutan.
A good alternative for bamboo
Proper opting of bamboo can be a task
17 Source: A sustainability approach to standards for rammed earth construction in Bhutan-Zareen 18 Source: Energy audit study by PwC 19 Source:www.mdpi.com/journal/sustainability 20 Source: Energy audit study by PwC 21 Source:http://ngm.nationalgeographic.com/ngm/photo- ontest/2011/entries/74906/view 22 Source: Energy audit study by PwC 23 Source: Energy audit study by PwC 24 Source:http://www.inbar.int/2012/01/bambooconstruction-bhutan/
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Glass Not cost effective
Good insulation (optional)
Locally available
Good life span
Fenestrations
Modern construction designs of institutions, hotels and offices chose glass glazing.
Glass was used for almost all windows.
25 An attempt to integrate traditional Bhutanese architecture with modern construction materials. 26
For certain multi- storey buildings, glass can be a good option according to climatic zones.
Cannot be used large numbers as it is not cost effective
Bricks Good thermal mass
Cost effective
Insulating
Can be locally Available
Good life span
Walls Wall thickness varies according to building type:institutions, rural and urban houses measuring 420 mm, hospitals, resorts and hotels measuring 305 mm, and offices with a measurement of 228 mm.
No insulation was provided, particularly for the brick walls.
Fenestration sizes increased due to good load bearing capacity.
27 New apartment building with the incorporation of traditional architectural features.
If made locally available, it can prove to be a good alternative for rammed earth construction.
Bricks, Walls, foundation plinth and RCC
Good thermal mass
Not cost effective
Available on some places
Good life span
Earthquake resistant
Framed structure
Foundation
Roof slab
Buildings such as offices, hospitals and hotels are built from RCC
In some multi-storied hotels, flat slabs were opted, with a thickness of 200 mm.
28 New construction with traditional architectural features incorporated at the facade level
Good strength characteristic, thus if production is made locally, being a standard material it can prove to be very useful
Earthquake resistant
Aluminum Not cost effective
Not available locally
Good life span
Fenestrations Most of the offices, hotels, resorts and hospitals used aluminum for windows as well as glazing’s.
Size and shapes varied according to the individual building requirement.
29
High energy consuming material.
Recyclable material.
25 Source: Sonam, Historic Districts as an alternative approach to preserve the Bhutanese Architectural Heritage, MIT 26 Source: Energy audit study by PwC 27 Source: Sonam, Historic Districts as an alternative approach to preserve the Bhutanese Architectural Heritage, MIT. 28 Source: Sonam, Historic Districts as an alternative approach to preserve the Bhutanese Architectural Heritage, MIT 29 Source: Energy audit study by PwC
Department of Renewable Energy, Ministry of Economic Affairs, Royal Government of Bhutan
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Steel Cost effective
Not available locally
Good life span
Roof
Walls
Glazing frame
Stairs
Not much of steel construction was found in Bhutan
Elements such as roof trusses and the stairs of urban houses were constructed using steel.
30 Aman Resort, Paro. Unique Bhutanese architectural features incorporated into modern amenities - Meeting the increasing demand for tourism infrastructure
Not preferable if cost is considered
Can be a good material for an earthquake resistant structure.
G I Sheets Thermal mass
Not cost effective
Insulation is needed
Locally available
Good life span
Roof Mostly, hotels and rural houses used GI sheets for their roofs.
31 Bhutan Elder Sangha Sanctuary, Bhutan
If used as a roof according to the climatic conditions, during the day it can get hot, while during the night it may release heat as quickly as possible.
30 Source: Sonam, Historic Districts as an alternative approach to preserve the Bhutanese Architectural Heritage, MIT 31 Source: http://www.tsao-mckown.com
Department of Renewable Energy, Ministry of Economic Affairs, Royal Government of Bhutan
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6.2. Building element construction
6.2.1. Foundations
Traditionally, foundations in Bhutan were always strip footings made from materials such as rubble
masonry and mud mortar, although cement mortar is now often being used. Some craftsmen insisted
that if cement mortar was used, a layer of plastic sheeting (to act as a damp proof course) needs to be
placed in between the top of the stonework and the mud. However, this was not a universal practice.
The key function of footings32 at the base of the wall is to protect the earth wall from moisture ingress,
and hence, although any simple mass footing can be used (such as concrete, masonry, cement
stabilized rammed earth), a continuous damp-proofing barrier must also be provided. The design of
the foundations for lightly loaded low- rise rammed earth buildings can follow rule of thumb
guidelines as prescribed by Walker and Maniatidis, 2003:65.
The dimensions of the foundations measured during site visits and obtained through interviews with
the skilled craftsmen were remarkably consistent and are summarized in Table 25. They have also
been checked against, and found to be consistent with, the dimensions found in traditional
architecture33.
Table 25: General guidelines for foundation dimensions in Bhutan
34
The dimensions of Bhutanese foundations were all found to be larger than those recommended in
various codes where the foundation depth as well as its width never exceeds 400 mm. A robust
drainage system is essential in protecting the rammed earth walls, and Bhutanese practice on this
aspect matched the guidance given by various national codes.
6.2.2. Walls
The minimum wall thickness found in Bhutan was 50 cm. Apparently, in this case, craftsmen were
given a design wherein the walls measured only 30 cm thick, due to which they feared a collapse,
and hence increased their thickness. Generally, the minimum thickness found was to be 60 cm (2 feet)
and greater, if the building was more than two storeys.
It is a standard practice in Bhutan to taper the walls of the buildings greater than two storeys, and
hence the wall thickness at the bottom of large buildings can reach over 1 m. Although craftsmen
explain the need for tapering as being the prevention of bulging and enhance the aesthetic value of the
buildings, Arya (2007:101) notes that tapering walls provide better stability against lateral forces and
hence are highly advantageous in seismic areas.
32 According to Walker et al. (2005:61) 33 DoWHR, 1993:191 34 *Imperial units are given since in practice the craftsmen invariably gave the measurements in feet and
inches.
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Figure 19 : Tapering walls at Bhutan35
6.2.3. Rabsel
Rabsel is a timber structure constructed with a series of vertical as well as horizontal members usually
found in the upper storeys of traditional building structures with a symmetrical distribution of infill
panels called ekra and window openings.
It is usually lighter than any other structure, and hence is usually found on the upper levels of a
traditional building in order to reduce its structural load on the load bearing walls. The hierarchy and
entitlement of these elements are significant in traditional Bhutanese architecture.
Figure 20 : Rabsel in walls
35 Source: Ministry of Works and Human Settlement (MoWHS)
Department of Renewable Energy, Ministry of Economic Affairs, Royal Government of Bhutan
Energy Efficiency Study in Building Sector
PwC 48
Elevation and a section of a typical rabsel36. Types of rabsels based on the geography of the region and
the height of the structure:-
Parop rabsel
Go-chham Thognyim rabsel
Lobur rabsel
Drey-Zhu rabsel
Gomang rabsel
36 (source: Historic Districts as an alternative approach to preserve the Bhutanese Architectural Heritage by
Sonam Gayleg)
Department of Renewable Energy, Ministry of Economic Affairs, Royal Government of Bhutan
Energy Efficiency Study in Building Sector
PwC 49
Nimchong rabsel
Shamig- ekra wall(bamboo frame)
Figure 21 : Types of rabsels used in walls in Bhutan37
6.2.4. Openings -Doors and windows
Windows and doors are traditionally kept to a minimum in Bhutanese buildings with the timber and
ekra frontage on the upper floors providing the light and ventilation required. They therefore
invariably comply with both load bearing and seismic design guidance which describes the maximum
total length of openings, distance to corners etc.
The openings are narrow, tall and divided into two or more layers and are usually found in the lower
part of the building. In a traditional building, the structural walls are usually rammed earth and stone
masonry which are load bearing walls and hence the openings at the lower level are small and narrow.
Payab windows Geykar window
Figure 22 : Traditional windows in Bhutan38
37 Source: Ministry of Works and Human Settlement (MoWHS) 38 Source: Ministry of Works and Human Settlement (MoWHS)
Department of Renewable Energy, Ministry of Economic Affairs, Royal Government of Bhutan
Energy Efficiency Study in Building Sector
PwC 50
Mago (Door)
This is the main entrance door of a building in Bhutan which has all the traditional details such as
Dhung, Pedma, Choetseg and bogh.
Figure 23 : Traditional windows in Bhutan39
6.2.5. Kachhen and Zhu
In Bhutanese buildings, kachhen is the timber column that is usually tapered with intricate carvings,
while zhu is the intermediate bow shaped timber bracket between the column and the beams above.
The bracket, shaped like a bow, reduces the length of the beam so as to increase the load bearing
capacity.
Figure 24 : Kachhen and zhu timber columns for load bearing in ceilings40
39 Source: Ministry of Works and Human Settlement (MoWHS) 40Source: Ministry of Works and Human Settlement (MoWHS)
Department of Renewable Energy, Ministry of Economic Affairs, Royal Government of Bhutan
Energy Efficiency Study in Building Sector
PwC 51
6.2.6. Cornices
Cornices are usually a part of the rabsel and form an integral element of the traditional Bhutanese
architecture.
Proportion: If width of the bogh is ‘b’ then the thickness of bogh a is ‘b’ plus 25 mm. The minimum
projection of a bogh equal to a band maximum ‘a’. Minimum spacing of ‘b' between these boghs is
1.75 b and maximum 2 b. The projection ‘c’ of the ohung and pedma is normally equal to b. The
minimum size of the bogh for the rabsels/ shall be 115 x 140 mm and maximum 150 x 175 mm.
Pictorial representation of the proportions of cornices41 Concrete cornice42
Figure 25 : Cornices in the walls
6.2.7. Roof
Heavy rainfall received during the summer and monsoon season in Bhutan, necessitates a
sloping roof in order to guarantee quick water discharge.
The sophisticated nailless roof construction is visually broken away from the true building. Its
structural design conveys the expression of a flying roof.
The space below the roof offers a welcome opportunity to dry skins, hay, etc.
The roof floor is insulated with a rammed earth layer with a thickness of approximately 10 cm.
The standard roof pattern is a pitched timber shingle covering, which is fixed through the
weight of stone boulders that are laid down over laths.
The slope of the pitched roof is approximately 12 to 15 degrees. A steeper roof is not possible
since the stones that fix the shingles will roll-off the roof.
41 Source: Traditional architecture guidelines by the Department of Urban Development and Housing 42 Source: Ministry of Works and Human Settlement (MoWHS)
Department of Renewable Energy, Ministry of Economic Affairs, Royal Government of Bhutan
Energy Efficiency Study in Building Sector
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Types of Roofs:
Gable roof
Hip roof Lean to roofs
Figure 26 : Types of roofs in Bhutan43
43 Source: Ministry of Works and Human Settlement (MoWHS)
Department of Renewable Energy, Ministry of Economic Affairs, Royal Government of Bhutan
Energy Efficiency Study in Building Sector
PwC 53
7. Key inputs or the Approach for the EE plan in buildings
Having surveyed, researched and understood the key construction practices adopted for buildings in
Bhutan, one can clearly conclude that with the growing urban sector, there will soon be a need to
retain vernacular building architectural practices in the country along with the deployment of
energy-efficient measures in the new buildings that are coming up. It is imperative that passive design
measures are to be introduced in all new housing as well as commercial developments in order to
reduce the load in buildings, and all active measures are to be made energy-efficient.
This can be best achieved by the following ways:
By following an integrated design approach and an efficient and integrated design process of
first reducing building loads and thereafter using energy efficiency measures.
Developing a set of green guidelines, retaining the traditional knowledge in the area of
construction, and recommending a series of passive design strategies for households and
other constructions.
After a sensitive design is achieved one can look at incorporating energy efficient measures to
further reduce the energy use in buildings. These are best achieved by recommending
Building Energy Efficiency Codes that address various active measures deployed in a building
including HVAC, lighting, envelope insulation, glass and fenestration, power and hot water
requirements.
Initiate policy measures such as the Appliance Standards and Labeling (S&L) program to
reduce energy consumption in domestic as well as commercial segments.
Initiate a program for improving firewood ‘Bukhari’ systems
Department of Renewable Energy, Ministry of Economic Affairs, Royal Government of Bhutan
Energy Efficiency Study in Building Sector
PwC 54
8. Efficient and Integrated Design Processes
A whole building design consists of two components: an integrated design approach and an integrated
team process. The integrated design approach brings together all the players of the building
stakeholder community, while the technical planning, design, and the construction team is to look at
the building design as a whole.
Whole building design in practice, also requires an integrated team process in which the design team
and all affected stakeholders work together throughout the project phases, and evaluates the design
for aspects such as cost, quality of life, future flexibility, efficiency, the overall environmental impact,
productivity, creativity, and ways in which the occupants will be enlivened. The whole building
process draws from the knowledge pool of all stakeholders across the life cycle of the project, right
from defining the need for a building, through processes such as planning, design, construction,
building occupancy, and operations.
When executed in the right manner, the integrated or whole building design process can result in cost-
effective buildings with significantly better performance as compared to business as usual. 44
Figure 27: Different stakeholder involved in building design
44 Whole Building Design Guide http://www.wbdg.org/resources/lcca.php
Department of Renewable Energy, Ministry of Economic Affairs, Royal Government of Bhutan
Energy Efficiency Study in Building Sector
PwC 55
Energy saving opportunity45
Energy savings can be achieved through technical improvements made to buildings and energy
consuming equipment so as to reduce energy waste (thereby increase energy efficiency) and by
conservation behaviours that do not necessarily compromise desired energy services (such as turning
out the lights when one leaves the room or having thermostats automatically adjust the
temperatures for unoccupied hours). From another perspective, it is important to address the issue of
energy waste during occupied as well as unoccupied hours. Proactive conservation behaviours as well
as robust operations and maintenance practices are critical for achieving the intended energy savings
of any technical improvements. Technical energy efficiency improvements that reduce energy
consumption in buildings fall under the following three broad categories:
Reducing the load,
Utilizing efficient systems to serve the load, and
Substituting with renewable energy where possible
Reducing the load
There needs to be a reduction in space heating, space cooling and lighting loads through energy
efficient building and site designs as well as their proper implementation. There are different design
techniques for reducing building envelope heat losses. In the climatic conditions dominated by
heating loads, it is important to isolate the building from its environment by a well-insulated and
airtight building envelope. In regions with cool climates, it is essential to minimize the daytime solar
gain through windows and lightweight roofs and walls. In other more moderate climates, the
significance of thermal insulation is not as prominent, and hence it is important for the building
envelope to be relatively responsive to the environment so as to efficiently address the varying needs
for heating, cooling, ventilation, and lighting.
Light reflective roofs and exterior walls are relatively low-cost measures for reducing cooling loads in
warm or hot and dry climates. Architectural details of individual buildings (form, orientation, and
shading, for example), landscaping, and ways in which buildings are oriented in a particular
construction site also affect the heating, cooling, and lighting loads and need to be considered within
the site planning and building design process. Water heating loads can be reduced through the use of
low flow plumbing fixtures. Lighting energy use can be reduced by day lighting design techniques
with light shelves that bounce the daylight further into a space, combined with automatic lighting
controls to dim or turn off electric lights in response to daylight conditions. The potential for cost-
effective reduction of heating and cooling loads using well-developed designs and broadly adopted
technologies is huge .
Utilization of efficient systems to serve the load
There is also a need to increase the efficiency of space heating, space cooling, ventilation, water
heating, appliances, other electric and electronic equipment, and lighting through technical
innovation and improved operational performance. Energy efficiency of HVAC systems is dealt with
both at the building design stage (proper sizing and selection of highly- efficient units that minimizes
the life cycle cost, and installation of controls) as well as through building commissioning and
improving operations and maintenance. With affordability levels showing a rise, the number of
appliances is also rising within household buildings in the developing nations. Utilization of energy
efficient appliances will further help curtail energy costs. Regulated standards and a labelling program
45 World Bank Working Paper No. 204, Mainstreaming Building Energy Efficiency Codes in Developing Countries – Global Experiences and Lessons from early adopters, Feng Liu, Anke S Meyer, John F Hogan
Department of Renewable Energy, Ministry of Economic Affairs, Royal Government of Bhutan
Energy Efficiency Study in Building Sector
PwC 56
for appliances, such as those in India and China, can ensure the import and use of efficient appliances
in Bhutan.
Substituting renewable energy
Bhutan needs to utilize renewable energy resources for energy services within buildings. This refers to
technologies that utilize natural heat sources and sinks directly (solar water heater, for example) or
indirectly (heat pump technology, for example) so as to reduce the consumption of fossil fuels and, at
the same time, the life cycle costs of relevant energy services. The suitability of such applications often
depends on site- specific conditions.
An energy efficient building design; implemented together with efficient heating and cooling
systems/equipment, represents the largest technical potential for energy savings in residential,
commercial, and public service buildings.
Life cycle cost analysis46
Design decisions must consider the life cycle cost for the entire building or project, and not just the
first cost considerations for an individual or isolated system or measure.
A life-cycle cost analysis (LCCA) is a method for assessing the total cost of facility ownership. It takes
into account all the costs of acquiring, owning, and disposing a building or a building system. LCCA is
especially useful when the project alternatives that fulfil the same performance requirements, but
differ with respect to initial and operating costs, have to be compared in order to select the option that
maximizes net savings. For example, LCCA will help determine whether the incorporation of a high-
performance HVAC or glazing system, which may increase the initial cost, but result in a dramatically
reduced operating and maintenance costs, is cost-effective or not.
46 Whole Building Design Guide http://www.wbdg.org/resources/lcca.php
Department of Renewable Energy, Ministry of Economic Affairs, Royal Government of Bhutan
Energy Efficiency Study in Building Sector
PwC 57
9. Green Building and Passive Guidelines
Building energy efficiency is primarily addressed by reduction in the loads and then by improvising
the systems’ efficiency levels. Passive design is followed by active design measures as the globally
accepted way of offering energy efficient building design. Here, a well developed code of its kind is
being referenced to namely, the Passivhaus Standard, Europe. It is expected that architects as well as
design engineers of the new generation of Bhutanese buildings will utilize this resource and
incorporate and customize these passive principles into their respective designs. Guidelines, if utilized
in conjunction with the code, are expected to yield greater success and uptake of the code amongst the
implementing community.
Figure 28: Passive/ bio-climate design strategies
9.1. Alternative Building Materials
With a boom in infrastructural development activities in Bhutan, high-embodied energy materials
such as cement, steel, bricks, glass, etc. are being utilized . Apart from being high embodied materials,
many of the conventionally used materials have become expensive , due to these materials being
imported from the neighboring countries. Therefore, there is an urgent need to look out for
alternative materials which are preferably available or manufactured locally. From an environmental
and poverty perspective, adoption of locally available low-embodied energy materials is highly
desirable in the country.
Some of the alternative building materials or technologies which may be consciously promoted in the
country are as follows:
1. Compressed stabilized earth blocks
2. Hollow interlocking blocks
3. Bamboo
Department of Renewable Energy, Ministry of Economic Affairs, Royal Government of Bhutan
Energy Efficiency Study in Building Sector
PwC 58
Alternative materials
Material Attributes Compressed stabilized earth blocks
47 CSEB blocks
Good thermal mass
Good insulation
Less polluting
Alternative for bricks.
Hollow interlocking blocks
48 Figure: A demonstration project using HI CSEB in
jemin, Bhutan
Good thermal mass
Energy efficient and eco friendly
Biodegradable materials
Cost effective.
Lateral load resisting capacity
Alternative for bricks
Bamboo
49
Biodegradable materials
Cost effective
Can be fabricated
Earthquake resistant
Good insulation
Allows a good fenestration space.
Replacement for timber and prefabricated sheets or tin sheets.
47 Source:www.projectneighbors.org 48 Source: Presentation by Jigme Tenzin at the 6th Annual Engineering Conference 49 Source: http://www.inbar.int/2012/01/bambooconstruction-bhutan/Bamboo in Bhutan:
Department of Renewable Energy, Ministry of Economic Affairs, Royal Government of Bhutan
Energy Efficiency Study in Building Sector
PwC 59
Compact Construction
In general, it is desirable to design buildings with high compactness. The more the compactness, the
lower is the heating demand. A design with medium-high compactness in required during the summer
season, because the cooling demand will be reduced. High compactness can be sacrificed sometimes
in order to have a higher surface oriented towards the south. In this situation, an intermediate
solution can be adopted with medium compactness.
9.2. Orientation
As far as possible, the longer axis of the building needs to be oriented in the east –west
direction.
Buildings needs to be spaced in such a way that they must not shade each other or block the
sun during winter.
9.2.1. Space orientation
Direction is such that it trap maximum solar energy during winter months.
The living spaces of a building must be designed as day lit spaces.
The non-living spaces, that is, the stair cases, washrooms, stores and garages may be planned
preferably on the northern side so as to provide as buffer to reduce heat loss from the living
spaces.
In warm and humid climate regions (the southern part of the country), high level of cross-
ventilation is required in buildings in order to maintain thermal comfort. Small size windows
need be placed on the windward side, while larger windows must be placed on leeward side
for facilitating direct ventilation through pressure difference.
In cold areas, all the main living areas, where applicable, are best orientated towards the
south so as to receive the maximum natural benefits of the sun, while other areas such as the
washrooms, corridors, etc., can be located in the northern side.
Wall orientation
Orientation is a parameter defined for each one of the external walls of the building. The orientation
must be obtained from the angle between the normal to the wall and the north direction. Accurate
orientation must have an adequate level of heat loss area oriented towards the south. This will
contribute to increased heat gains due to solar radiation, and it is mandatory in this case to design the
southern walls with a high percentage of glazing. During the summer season, this measure requires a
well-designed system of solar control because in other cases, the building or at least the adjacent zone
will be overheated. East and west orientation are avoided because the level of radiation in these
directions is low during winter, and also in the summer season, solar control is much more
complicated than in south orientation.
Window and door orientation
The northern facade must have minimum door and window openings.
The southern facade needs to have maximum glazing in order to capture maximum solar
heat during winters.
Department of Renewable Energy, Ministry of Economic Affairs, Royal Government of Bhutan
Energy Efficiency Study in Building Sector
PwC 60
It is recommended that for a new construction, glazing must be in proportion to the total
surface area of the wall and preferably must not exceed more than 50% in the mid-altitude
region, that is, 1500 to 2,200 m, and not more than 70% in the high altitude regions, that is
2200 m and higher.
The size and position of doors, windows, and vents within the envelope must be evaluated
after a careful consideration of aspects such as day lighting, heating, and ventilating
strategies.
The main windows and balconies need to be designed to face the south and south-east
direction for solar gain. North-facing windows can be limited since there is no solar gain
towards this direction.
The percentage of glazing surface related to the floor area needs to be around 20% to the
south, and 5% to the north. A good orientation of the building is a goal for all climatic
regions.
Insulation
Ground Insulation
The ground temperature two to three meters deep inside the earth, is only slightly higher than the
annual average air temperature during the whole year. The same is true below floor slabs: Diurnal, but
even annual changes in temperature occur mainly near the boundary.
Depending on the climate and general building properties, insulation of the floor slab or the basement
can be necessary, useful or counterproductive.
However, insulation is usually thinner than that present in building elements adjacent to the ambient
air where the heating energy demand can already be minimized by other means, insulation of the floor
slab as well as the basement can be omitted, using the ground as a heat sink during the summer
season.
Insulation can be placed below the floor slab if the material can resist factors suchas pressure and
humidity; it is also possible to install the insulation above the floor slab. A snapshot of ground
insulation is presented at Figure 29.
Figure 29: Ground Insulation50
50 Source: the passivhaus standard in European warm climates: design guidelines for comfortable low energy
homes.pdf
Department of Renewable Energy, Ministry of Economic Affairs, Royal Government of Bhutan
Energy Efficiency Study in Building Sector
PwC 61
Figure 30: Plinth protection provided by sloping paving for drainage channel51
Figure 30 shows that a proper drainage system can prevent water logging near the building
foundation and hence keep the soil beneath free from any climatic disturbance. Therefore, it provides
a hand in ground insulation.
Wall insulation
Environmentally sensitive insulating materials, made from recycled materials such as cellulose or
mineral wool, need to be considered, if such items meet the project’s performance as well as budgetary
criteria.
Insulation of the walls reduces the average heat flow through the wall construction. The effect is
characterized by the U-value, given in the formula W/(m2K), which signifies the heat flow through
one square meter of the wall area at a constant temperature difference of 1 K (= 1 °C). Although, there
are variations in the heat flow due to the constantly changing boundary conditions, the U-value
represents the average heat flow through the wall.
Good insulation of walls limits heat losses during the winter season and increases the interior surface
temperatures, thus increasing thermal comfort and reducing the risk of damages due to excess
humidity.
Sufficient wall insulation is therefore indispensable for the reduction of heating energy demand in
winter. Well-insulated walls also help to reduce the amount of heat that is transferred into the
building during the summer heat waves. They support both natural ventilation strategies as well as
energy-efficient active cooling concepts, whenever the interior temperature drops below the daily
average of the exterior surface temperature.
51 Source: A sustainability approach to standards for rammed earth construction in Bhutan by Zareen Sethna
(CL)
Department of Renewable Energy, Ministry of Economic Affairs, Royal Government of Bhutan
Energy Efficiency Study in Building Sector
PwC 62
Figure 31: Snapshot of a 40 cm gable wall compound insulation system and a porous ceramics brick52
Roof insulation
Good insulation of the roof is necessary in order to reduce the winter heating energy demand. Concerning insulation thickness, there are usually less constructive constraints in the roof than in the walls. Therefore, roof insulation is typically dimensioned thicker than wall insulation. Well-insulated roofs are also a good solution for reducing the summer heat load.
Insulation in inclined roofs can be applied between roof rafters or on top of the rafters below the tiles. For concrete roofs, exterior insulation above the concrete is useful. With modern, water-resistant insulation materials, the lifespan of the main waterproofing layer can be increased by installing it between the insulation and the concrete.
Figure 32: An inclined roof with insulation with respect to the rafters and highly insulated concrete roof construction53
52Source: the passivhaus standard in European warm climates: design guidelines for comfortable low energy
homes.pdf 53 Source: the Passivhaus Standard, European Union warm climates: design guidelines for comfortable low
energy homes.pdf
Department of Renewable Energy, Ministry of Economic Affairs, Royal Government of Bhutan
Energy Efficiency Study in Building Sector
PwC 63
Thermal mass
Thermal mass, coupled with the interior of the building, can be of a considerable advantage both in
the summer as well as winter season. During summer, it can be used to limit the upper daytime
temperature and thereby reduce the need for cooling. This effect can be enhanced by coupling the high
capacitance material with night time convection to pre-cool the thermal mass for the following day.
Figure 33 gives the snapshot for a thermal mass in a building.
Figure 33: Snapshot for thermal mass in a building54
Preference must be given to use local materials that is stone, slate and mud and other such
construction practices so as to reduce heat loss and maintain adequate thermal comfort during peak
the peak winter months.
Figure 34 : Pictorial representation of radiation of heat during day and night55
Thick stone masonry or rammed earth walls may be used to serve as thermal mass in order to the
building and also to absorb solar gains to heat the building. Materials such as tiles, stone, or masonry
floors need to be considered for heat storage.
54 Source: the Passivhaus Standard, European Union warm climates: design guidelines for comfortable low
energy homes.pdf 55 Source: the Passivhaus Standard, European Union warm climates: design guidelines for comfortable low
energy homes.pdf
Department of Renewable Energy, Ministry of Economic Affairs, Royal Government of Bhutan
Energy Efficiency Study in Building Sector
PwC 64
Figure 35: Construction from rammed earth56
Integrating solar heating systems
Passive solar heating systems such as solar air heating, water heating, sun space, solar walls, space heating green houses and solar trombe wall, etc. shall be integrated within the building design wherever possible on the southern side, so as to allow maximum direct solar access to these systems.
The suitability of space heating systems is to be installed or incorporated within the design of a solar passive building and needs to be decided by either the architect, engineer, designer or solar expert in accordance with the building site, climate and space heating requirements.
Trombe wall
A south-facing masonry wall covered with glass, spaced a few inches away. Sunlight passes through
the glass and is absorbed and stored by the wall. The glass as well as the airspace keeps the heat from
radiating back to the outside. Heat is transferred by conduction since the masonry surface warms up,
and is slowly delivered to the building, a couple of hours later.
56 Source: http://www.raonline.ch/pages/bt/cult/bt_archi0201.html
Department of Renewable Energy, Ministry of Economic Affairs, Royal Government of Bhutan
Energy Efficiency Study in Building Sector
PwC 65
Figure 36: Pictorial representation of working of Trombe wall57
They provide carefully controlled solar heat to a space without the use of windows and direct sunlight,
thus avoiding potential problems from glare and overheating, if thermal storage is inadequate. The
masonry wall is part of the building’s structural system, effectively lowering costs. The inside, or
discharge, surface of the Trombe wall can be painted white to enhance lighting efficiency within the
space. However, the outside large dark walls sheathed in glass must be carefully designed for both
proper performance and aesthetics.
The characteristics of a solar wall as compared to a direct gain window are as follows:
Its efficiency in collecting solar heat is not as high as a direct gain window of the same size.
The night heat losses are less than for a direct gain window.
The structure is very simple without —fans, ducts, controllers.
It does not provide day lighting or views as a direct gain window would
The inside surface of the wall can be used to some extent, but should not be covered with
anything that reduces heat transfer from the wall to the living space.
Depending on the current wall construction, it may be easier to retrofit a solar wall than to
retrofit a direct gain window because , no wall structural members are cut.
Advantages
Comfortable heat: It radiates in the infra red, which is more penetrating and pleasant than
traditional convective forced air heating systems.
Passive: It has no moving parts and essentially no maintenance.
Simple construction: This is relatively easy to incorporate into building structure as an
internal or external wall. Materials (masonry, concrete) are relatively inexpensive.
Effective: It can reduce heating bills by large amounts.
57 Source: http://suryaurza.com/trombe-wall/
Department of Renewable Energy, Ministry of Economic Affairs, Royal Government of Bhutan
Energy Efficiency Study in Building Sector
PwC 66
Figure 37: Working of Trombe wall in respect to day and night58
Sun spaces
A sunspace or solarium is a combination of direct and indirect gain systems. Solar radiation heats up
the sunspace directly, which, in turn, heats up the living space (separated from the sunspace by a mass
wall) by convection and conduction through the mass wall.
The basic requirements of buildings heated by sunspace are as follows:-
A glazed south facing collector space attached yet separated from the building and living space is separated from the sunspace by a thermal storage wall
Sunspaces can be used as winter gardens adjacent to living space
Figure 38: Trombe wall vs. sun space59
Important considerations for sunspace design are as follows:
In cold climates, double glazing reduces conductive losses through the glass to the outside.
Insulated panels, shades, or blinds are more important for sunspaces than for Trombe walls, as sunspaces are sometimes occupied.
As with Trombe walls, the darker the internal surfaces of the sunspace, the more effectively the thermal mass can store heat during the day.
Do not overpopulate conservatories with vegetation, as foliage can reduce the system's heat capture by significantly shading the floor and wall.
58 Source: http://suryaurza.com/trombe-wall/ 59 Source: http://suryaurza.com/trombe-wall/
Department of Renewable Energy, Ministry of Economic Affairs, Royal Government of Bhutan
Energy Efficiency Study in Building Sector
PwC 67
Natural ventilation
The amount of ventilation required varies according to the season. In order to provide for our
physiological needs and to maintain internal air quality, a minimum of 8-10 liters per person per
second is required.
Figure 39: Types of ventilation that can be implemented in Bhutan60
The warm and humid climate regions (southern part of the country), require a high level of cross
ventilation in the buildings to maintain the thermal comfort. Small size windows should be placed on
the windward side, while larger windows should be placed on the leeward side for facilitating direct
ventilation through pressure difference.
Infiltration and air tightedness
Leaky building envelopes cause a large number of problems, particularly in cooler climates or during
cooler periods. Airflows from the inside to the outside through cracks and gaps result in a high risk of
condensation in the construction. Infiltration results in a penetration of cold air, which makes
inhabitants uncomfortable. Cold air infiltration also increases the temperature difference between
different storeys of a building. Finally, using cracks in the building shell for ventilation purposes does
not provide sufficient air change unless the envelope is so leaky that drafts and discomfort occur
frequently.
Good air tightness is mainly achieved by appropriate design.
On the contrary, airtight buildings without ventilation
systems run the risk of bad indoor air quality and excess
humidity.
Figure 40: Sealing tape for plaster for air tightness61
60 Source: the Passivhaus Standard, European Union warm climates: design guidelines for comfortable low
energy homes.pdf 61 Source: the Passivhaus Standard, European Union warm climates: design guidelines for comfortable low
energy homes.pdf
Department of Renewable Energy, Ministry of Economic Affairs, Royal Government of Bhutan
Energy Efficiency Study in Building Sector
PwC 68
10. Building Energy Efficiency Code62,63
The Building Energy Efficiency Code of Bhutan has been modeled on the Energy Conservation
Building Code of India and partly also references ASHRAE/ ASTM/ ISO and IS standards and Bhutan
Green Building Guidelines for the various parameters for which it sets out performance benchmarks.
Although, if there is a need to establish more accuracy, a larger code development process would be
required.
More importantly, for the Code to be referred to as a legal document by the building, implementing
and enforcement community of Bhutan, there needs to be in existence an Act/ a Law of the land
thereby providing the BEEC document and a nodal agency governing it the legal framework to
administer further developmental strengthening, adoption, implementation and enforcement in the
future.
The Bhutan BEEC document presented in the Annexure L(and as modeled on the lines of ECBC) is an
important step towards promoting energy efficiency in the building sector. It is written in code
enforceable language. We hope to address the views of the manufacturing, design and construction
communities expected to be similar to the Indian context -- as an appropriate set of minimum
requirements for energy efficient building design and construction. The purpose of the BEEC
document is to provide the minimum requirements for energy efficient design and construction of
buildings and their systems. These buildings can act as ready reference for various stakeholders as
well as a base document for further developmental strengthening.
As far as the numerical references to the various code component benchmarks (read Envelope,
Lighting, HVAC etc.) are concerned, this BEEC document references ASHRAE 90.1 and ECBC 2007
numerical values for the envelope section. All the other Code components refer to the ECBC 2007
numerical values and compliance approaches since the building design and construction market
realities of both the developing nations, India and Bhutan are closely linked and similar.
Figure 41: Methodology for building energy code compliance
62 Energy Conservation Building Code User Guide, 2009, Bureau of Energy Efficiency, India 63 Energy Conservation Building Code, 2007, Ministry of Power, Government of India
Department of Renewable Energy, Ministry of Economic Affairs, Royal Government of Bhutan
Energy Efficiency Study in Building Sector
PwC 69
Compliance paths to ECBC 2007 in India64, BEE
Compliance approach to the BEEC plans are currently proposed to follow two optional paths : -the
prescriptive approach and the performance approach. Prescriptive requirements in most codes are
component specific and specify minimum performance criteria for building systems such as building
envelope, HVAC and lighting. Envelope performance criteria vary according to climate zone and
building occupancy type. Building materials and systems are chosen and specified according to the
code requirements. This is a step- by- step path that requires the user to show the compliance of the
design and construction practices towards the list of prescribed requirements. Most prescribed
requirements are associated with a performance characteristic of the building material to be used.
This path does not allow flexibility as all prescriptive requirements must be met if one chooses to
follow it.
A performance based approach in general refers to specifying the annual level of overall energy
consumption (energy budget) in the targeted building and the methodology to calculate the sub
budgets of different energy uses regulated by the energy code, such as space conditioning, lighting,
and service water heating. It is an alternative method to comply with the code. In order to comply with
this method, an hourly energy simulation needs to be performed as per the code. The 'Whole Building
Performance' method is more complex than the 'Prescriptive method', but offers considerable design
flexibility.65
Given that the energy code is a highly technical document and will be primarily used by architects,
engineers, builders and government officials, appropriate training and capacity building of this
stakeholder group to easily understand and use the code should be taken up as a priority.
The BEEC addresses five broad components in the building;
Building envelope
Heating, Ventilation, Air Conditioning
Lighting
Power
Service hot water
As seen from the international review, most codes, as proposed for Bhutan too, consist of the above
five building components to address energy efficiency in the building design and construction. These
components can be monitored for energy efficiency and cover the entire building energy use of the
building.
Building Envelope
The building envelope refers to the exterior
façade, and comprises of opaque components
and fenestration systems. Opaque components
include walls, roofs, slabs on grade (in touch with
the ground), basement walls, and opaque doors.
Fenestration systems include windows, skylights,
ventilators, and doors that are more than one-
half glazed. Envelope design strongly affects the
visual and thermal comfort of the occupants, as
64 Energy Conservation Building Code User Guide, 2009, Bureau of Energy Efficiency, India 65 Energy Conservation Building Code User Guide, 2009Bureau of Energy Efficiency, India
Department of Renewable Energy, Ministry of Economic Affairs, Royal Government of Bhutan
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well as energy consumption in the building, as heat transfer from between the exterior and interior of
the building takes place through the envelope. The code specifies minimum heat transfer values for
roofs walls and fenestration for the different climate zones.
Walls
Heat transfer takes place through walls, windows, and roofs in buildings from higher temperature to
lower temperature in three ways-conduction, convection, and radiation. Conduction is the transfer of
heat by direct contact of particles of matter within a material or materials in physical contact.
Convection is the transfer of heat by the movement of a fluid (air, gas or liquid). Radiation is the
movement of energy and heat through space without relying on conduction through the air or by the
movement of air.
Roof
The heat transfer process involved in the roof, is similar to the heat transfer that takes place in a wall.
Heat transfer across the roof is more prominent compared to the wall because of higher incidence of
solar radiation.
Depending on the properties of the
roof material and construction, the
roof reflects a part of the solar
radiation back to the environment,
and absorbs the other part of the
heat in the roof. Finally, a portion of
the absorbed heat in the roof is
emitted as long-wave radiation back
to the environment and the
remaining part of the absorbed heat
is carried inside the building. This heat transfer process is governed by the 'Solar Reflectance' and
'Emissivity (Thermal Emittance)' properties of the roof material, apart from the thermal conductivity
of the materials used in the roof.
Fenestrations
Heat transfer across glazing products or
fenestration (windows, door, and skylights) is
similar to the heat transfer that takes place
across walls and roofs through conduction and
convection.
In addition, direct solar radiation contributes
to solar heat gain through the fenestration
Key Performance Indicators for building envelopes components such as walls, roofs and insulations
material used are as follows:
Parameters such as U value, R value, thermal resistance,
U-factor for wall materials , roof , insulations (glasswool, thermocol, EPS and XPS, PUF
etc.)– lower the better
Power savings in kWh
Synergy
Application and benefits
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system. The ability to control this heat gain is characterized in terms of SHGC. SHGC is the ratio of the
solar heat gain that passes through the fenestration to the total incident solar radiation that falls on
the fenestration.
Table 26: Key performance indicators for fenestration
Fenestration
Name High performance glass
Parameters Performance of a glass can be measured by rating it on a
scale of 1-5 based upon following parameters :
SHGC ( Solar heat gain coefficient)
U value ( Heat transfer coefficient)
VLT ( Visible light transmission)
Air tightedness
U factor(U factor lower the better) High performance glass : W/m2.deg.k
Normal glass : W/m2.deg k
Power saving WIP
Synergy HVAC
Heating Ventilation and Air Conditioning
Heating, Ventilation and Air Conditioning (HVAC) refers to the equipment, distribution systems, and
terminals that provide, either collectively or individually, the heating, ventilation, or air-conditioning
requirement to a building or a portion of building. HVAC energy use in a commercial building can
increase and decrease significantly depending on how efficiently the combination of air side systems
and central plant operates. This component is not that significant in most of Bhutan given the cold
climate of the region.
The best HVAC design considers all the interrelated building systems while addressing indoor air
quality, thermal comfort, energy consumption, and environmental benefits.
The Code determines the minimum equipment efficiencies for air conditioning systems, chillers and
economizers. It also determines the minimum insulation in the ductwork.
Table 27: Key performance indicators for HVAC
HVAC
Name Energy efficient air conditioning system
Parameters ASHRAE 90.1 2010 has set down parameters for :
EER (Energy Efficiency ratio - heat removal in BTU/h divided by
input in watts)
COP
Application and
benefits
Application
Heating, cooling,
Maintaining desirable humidity and temperature levels,
Improves indoor air quality, increases comfort level of occupants
Helps in achieving proper ventilation
Benefits
An efficient system with proper design, installation and operation
would reduce the air-conditioning load by more than 20 %.
COP As per minimum standards
EER As per minimum standards
Controls Any HVAC system should be temperature controlled and shall be capable of
providing a temperature band as specified in ECBC
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Power saving WIP
Service Water Heating and pumping
BEEC through mandatory requirements seeks to minimize energy usage in water heating systems by
taking the following initiatives:
• Utilizing solar water heating
• Specifying heating equipment efficiency
• Maximizing heat recovery and minimizing electric heating
• Insulating hot water storage tanks and pipelines
• Reducing standby losses
• Reducing heat and evaporation losses in heated swimming pools
For some building types such as large hotels and hospitals service water heating can be a major energy
consumer. Inefficiency in water heating is caused primarily by inefficiency of the heating equipment,
and by heat loss from hot water storage tanks and the distribution piping network.
The code determines minimum efficiencies of hot water systems, minimum insulation in hot water
piping and water pumping systems.
Lighting
Lighting accounts for 15% of total energy consumption in buildings in Bhutan. Lighting is an area that
offers many energy efficiency opportunities in almost any building facility, existing or new.
While energy efficiency is essential for many reasons, lighting designers also need to consider a host of
other factors, including the effect of quality of light on the visual comfort and productivity of the
occupants. Small improvement in lighting quality can improve productivity of the user substantially.
In practice, the right quality and quantity of light can be provided efficiently (with less energy) by
using the right technology and its effective integration with daylight.
The code determines minimum lighting power densities for interior and exterior lighting powered by
electricity. It also mandates the use of lighting controls.
Table 28: Key performance indicators for lighting
Lighting
Name Energy efficient lighting
Parameters Efficacy of lighting technologies
Energy consumption
Life
LPD Any technology in the area of lighting should be able to cater to the area as specified by Code in terms of LPD
CRI Quantitative measure of its ability to reproduce the colors of various objects faithfully in comparison with an ideal or natural light source. Higher the better.
LED lamps have achieved CRI up to 95.
Need to assess the benchmarking
CCT The CCT rating for a lamp is a general "warmth" or "coolness" measure of its appearance. However, opposite to
Department of Renewable Energy, Ministry of Economic Affairs, Royal Government of Bhutan
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the temperature scale, lamps with a CCT rating below 3200 K are usually considered "warm" sources, while those with a CCT above 4000 K are usually considered "cool" in appearance.
Reflector performance WIP
Power saving WIP
Synergy HVAC and lighting loads
Electrical Power
The Building Energy Efficiency Code has only mandatory requirements for the electric power systems
installed in buildings. These provisions are related to distribution transformers, electric motors,
power factor and distribution losses.
It is clarified here that building code in any country requires a detailed market as well as technical
analysis to finalize requirements. This draft code document is a structure for understanding different
stakeholders in Bhutan and requires much detailed work and a legal process before finalized for
Bhutan. The draft code structure is attached at Annexure-L.
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11. Implementation Framework
The process of code development, implementation and enforcement is a rather comprehensive and
collaborative process amongst various stakeholders from the building industry and the government
bodies at central, state and city levels.
Standards and codes are developed at the central government level. Subsequently the central
government advises all the state/ local governments and the stakeholders for their voluntary or
mandatory adoption at the state or local or city levels.
There are several aspects that come into play at the various stages of development, enforcement and
compliance of BEED.
The development of the code document itself is a stakeholder based and consensus driven process. It
is an iterative process with wide stakeholder participation, informed by field surveys and market
assessment of materials technologies and their costs. Technical values are determined by conducting
actual simulations of buildings to determine energy efficiency potential and cost effectiveness of the
code.
After the code document is finalized, there are three aspects to enabling and ensuring compliance with
codes at the state and local government levels.
Adoption: – This is the process of making amendments to the national code and incorporating the
provisions in the local bye-laws and development requirements.
Implementation: - This is the process of designing and constructing buildings to meet the amended
provisions incorporated in the local bye-laws and development requirements.
Enforcement: - This is the process of checking the buildings to ensure that the buildings meet local
bye-laws and development requirements.
Most of these processes have already been undertaken in the development of the building energy code
of Bhutan as is being recommended by way of this document, but a lot of the work still remains to be
done.
The attached flow chart gives a detailed overview of the current status with respect to code
development in Bhutan.
Table 29: Flowchart for different stages of building energy efficiency code for Bhutan
Department of Renewable Energy, Ministry of Economic Affairs, Royal Government of Bhutan
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Ph
as
es
Legal Framework
Code Development Process - Phase 1
Code Development Process - Phase 2
Proposed Stakeholder/ Actor
Output D
EV
EL
OP
ME
NT
- I
nit
ial
Mandate International Review DRE
National Review DRE Local Survey and establishing national trends
Construction Practices DRE Building-vide Energy Baseline
Determination of Climate Zones DRE
Referenced Standards DRE
Stakeholder Identification DRE Fixing roles and responsibilities
Compliance methods and options DRE Simple or Flexible
Develop Code Document DRE Stakeholder Feedback
DE
VE
LO
PM
EN
T -
S
tre
ng
the
nin
g
Bhutan EE&C Act Nodal Agency (TBD) Policy Goals for Buildings Energy Efficiency
Techno-Economic markets assessments for building
materials and technologies
Nodal Agency (TBD) Performance Benchmarks, Availability of materials
established
Whole building performance and life cycle analysis
Nodal Agency Savings potential and cost effectiveness established
Stakeholder Research/ review
Stakeholders Consensus
Public Review of Code Document
Public Refinement
AD
OP
TIO
N Authority having
Jurisdiction at the Centre
Adoption of Code Local Government Incorporating BEEC in Local Bye-laws
IMP
LE
ME
NT
AT
ION
Institutional framework for Code
Implementation
Project Management Unit
Training and Capacity Building
Nodal Agency (TBD), PMU
Greater up-take from the market
Public awareness Nodal Agency (TBD), PMU
Ease of administration
Compliance Forms, Guidebooks, Model Admin.
Procedures for checking compliance and enforcement
Project Management Unit
Greater up-take and ease of administration
Evaluation of energy savings of Code
Project Management Unit
Determination of effectiveness of Code
Maintenance of Code Nodal Agency/ PMU
EN
FO
RC
EM
EN
T
Authority having Jurisdiction at the
Centre
Administration and Enforcement of the Code
Local Administrative Authority having
Jurisdiction
Specify building permit rules and regulations
Local Administrative Authority having
Jurisdiction
Compliance
Development of Enforcement Roadmap
Local Administrative Authority having
Jurisdiction
Compliance
Pilots and Demonstration Projects
Nodal Agency/ PMU
* Text in red denotes- Actions undertaken during the current study by the Department of Renewable Energy for code development.
Text in green denotes - Proposed future actions.
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11.1. Key actions required for implementation
Developing a building energy code is a rather elaborate process requiring a variety of data and analyses.
As it's been observed in the preceding sections, a lot of preliminary work has already been done for this work.
Even though a code document has been drafted, a lot more effort needs to go into this exercise to make the code
a robust document. The following activities can be distinguished as part of the building energy code
development process:
11.1.1. Policy development
Development of Bhutan Energy Conservation Act or Law, which is the pre-requisite for this kind of
work.
Identify nodal agencies at national as well as local level to speed up code activities
11.1.2. Market assessment
Detailed survey of local buildings: A detailed survey of local buildings to collect information
about the building stock and its energy use and determine typical base case buildings to be used
as benchmarks for developing and evaluating code requirements. Local climate data and information
on the local availability and costs of construction equipment and materials need to be gathered as
well.
Computer based simulations: Technical, energy, and economic analysis, including computer
based simulations applied to base case buildings to estimate energy savings and cost effectiveness
of proposed code requirements. Knowledgeable local designers and contractors are a key source
of professional judgment and should therefore be consulted early on in the building energy code
development and adoption process.
Strengthening the building code: The building energy code should include detailed and objective
documentation (for example, technical data such as equipment ratings or tables of default values),
explicit standard requirements, including compliance forms (that are easy for inspectors to
check), and alternate compliance options. In the case of performance based compliance, a computer
software performance method with specialized compliance software (computer simulations of
building energy use). Provisions for continued building energy code maintenance and regular code
revision and updates should be created.
Public review with key stakeholders: The inclusion of key stakeholders in the code development
process allows issues to be sorted and addressed before the building energy code is finalized. It also
greatly increases the likelihood that the key stakeholders will support the building energy code once it
is adopted and work to see it utilized within their trade or professional organization.
After a public review of the final building energy code draft and inclusion of comments, it would be officially
adopted as a voluntary or mandatory code. Four issues need to be considered for strengthening and finalization
of a building energy code:
1. A decision needs to be made whether the code should emphasize simplicity (and thus easier
application) or provide for flexibility to allow designers and architects to find effective ways to meet
the code requirements. In new code developments that cover all new buildings, often both prescriptive
and performance based compliance paths are introduced, allowing designers to choose. Especially for
smaller, less complex buildings, the simpler prescriptive path is preferred.
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2. The code takes into account the local availability and costs of equipment and materials.
3. The code requirements should be beneficial as a whole. This means that any additional costs of
implementing the necessary measures, plus the costs of any supporting programs are balanced by
energy savings and other benefits over the lifetime of the building, if not less. The code developers
should thus use a life cycle cost (LCC) analysis and specify those measures that have the biggest impact
on energy savings for money spent.
The development and later implementation and enforcement of the building energy code do not take place in an
institutional vacuum. Implementation, enforcement, and the future sustainability of a code will be enhanced if
the following arrangements are put into place during the development stage.
Figure 42: Steps for implementation, enforcement and stability of code
A project unit will manage the development process. The unit should be directly linked to the
government unit or agency in charge of code development.
Consultants will perform various market research and analysis tasks.
The standing committee will have a strong involvement from local experts in the development process.
This includes task forces to tackle specific points.
There can be links with relevant organizations. This can be in the form of a working group of
stakeholders that would review outputs and participate in acting on realistic and relevant
Policy goal for BEEC
Survey local buildings,
benchmarking; survey
construction materials market
Technical, energy economic analysis to
estimate energy savings/cost-
effectiveness of proposed measures
Code document drafting
Development of compliance
forms/procedures, guidebooks,
administrative procedures for checking
compliance
Training and capacity building, public awareness
Evaluation of energysavings and BEEC effectivenss
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recommendations.
There will be a public process for review and integration of comments.
A structure to supervise the implementation process.
An enforcement agency (if mandatory) will be employed.
Formation of a group that can maintain and update the code in the future will be necessary.
For building energy codes that can be actually applied and result in energy savings, the development of the code
must be supported by the build-up of an implementation and, eventually, enforcement infrastructure including
compliance check methods and enforcement roadmaps. Finally, no building code shall be successful without
building capacity throughout the entire building supply chain and amongst architects, engineers, builders and
local government officials. Consumers need to be made aware of the benefits of energy efficiency investments in
buildings.
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12. Policy Instruments -
Recommendations The report has so far provided an overview on various energy efficiency and conservation opportunities in
building sector at Royal Kingdom of Bhutan. The report also mentions the importance of having BEEC
(building energy efficiency code) and how the energy efficiency in existing and upcoming buildings can be
enhanced through implementation of practices prescribed in the code.
However, merely prescribing the best practices in the interest of energy efficiency cannot lead to wider
acceptance in the society. Energy efficiency generally works on a push-pull mechanism. Implementation of
energy efficiency measures on a country wide scale requires a guided support from the government. The
government can introduce policies that improve energy efficiency in the energy intensive sectors. Thereafter the
government can push the implementation of policies through appropriate enforcement measures and can pull
the society through various capacity building initiatives.
Having realised the importance and need of energy efficiency measures in Bhutan, it is recommended that the
energy sector stakeholders (as per the governance structure) shall jointly work and define policies for wider
implementation of energy efficiency measures. This will create an environment favorable for sustained energy
efficiency improvements.
Based on the findings of this study, here are some recommendations on introducing energy efficiency policies
in the country.
Introduction of Energy Conservation Act or Law in Bhutan – Prerequisite.
Launch of Standard & Labeling (S&L) program for equipments and appliances – Will benefit all
building types.
Initiate exercise for implementation of practices prescribed in building code – Long term
phenomenon.
Launch of program for improvement of Bukhari system – Households.
Initiate capacity building programs and strengthen ongoing awareness programs
12.1. Introduction of Energy Conservation (EC) Act in
Bhutan
Enactment of an EC Act in Bhutan is a prerequisite for large scale deployment of energy efficiency measures.
The prime objective under the EC Act is to reduce the energy intensity of the economy. The EC Act can be
referred as a supreme document created under the judicial powers of the country. The act can empower the
government of Bhutan to create a nodal institution that has the responsibility and authority to spearhead
energy efficiency measures in the country.
The Act can be considered as a legal and operational document which empowers the government to develop and
enforce policies so as to channelize large scale implementation of energy efficiency measures. Some of the key
areas (but not limited to) that can be part of the EC Act are given below.
Notify the energy intensive sectors in the country where it is important to introduce energy efficiency
measures.
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Introduce measures and policies to stimulate energy efficiency practices in energy intensive sectors.
Empowers the government to enforce policies in the interest of energy efficiency and conservation.
Prescribe the energy consumption standards for equipments and appliance through introduction of
S&L programs.
Empower the government to regulate the market so as to control the quality of electrical products
entering in Bhutan through imports.
Prescribe practices under building energy efficiency code for efficient use of energy in buildings in the
country.
Empower the government to initiate monitoring and verification activities to check the compliance
under energy efficiency norms and ensure integrity under various energy efficiency and conservation
initiatives.
Promote research & development in the country.
Formulate and facilitate implementation of pilot projects and demonstration project.
Create awareness and disseminate information on energy efficiency policies and measures.
Empowers the government to initiate capacity building programs in the interest of energy efficiency.
Promote opportunities for innovative financing of energy efficiency programs in the country.
Define legal rules and empowers the government to have a tribunal to for energy sector.
The Act will be useful to establish systems and procedures for implementation of energy efficiency and
conservation practices in the country. Taking reference from the powers under the act various policies can be
framed, some of which are shared next.
12.2. Launch of Standard & Labeling (S&L) program
The energy efficiency program in the equipment and appliances sector is globally referred as standards &
labeling (S&L) program.
Energy efficiency labels are informative labels affixed to the products to describe the product’s energy
performance (usually in the form of energy use, rating). These labels give consumer the information
necessary to make informed purchases.
Energy efficiency standards are well defined protocols which are used to obtain a sufficiently accurate
estimate of the energy performance of a product in the way it is typically used, also it target limits on
energy performance based on specified test protocols.
The objective of this program is to provide the consumer an informed choice about the energy saving and
thereby the cost saving potential of the relevant marketed product. Without a credible energy label, a consumer
looking at an appliance has no idea whether a product saves energy or is an energy guzzler. The energy usage
pattern of an appliance is usually not predictable, and invariably not known to the user. Similar to other energy
efficiency programs, energy labeling aims to the market transformation of energy using products and
appliances toward greater energy efficiency.
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The energy labeling programs help consumers to understand which products are most efficient and help them
to choose the more efficient ones. At the same time, they create healthy competition among manufacturers to
produce and market the most energy-efficient models and thus promote efficiency.
In Bhutan, a large portion of demand in appliances sector is met through imports. Considering the context of
Bhutan, since at present there is no energy efficiency qualification criterion for import of appliances there is a
probability for getting imports of cheap and in-efficient products from the neighboring countries. Hence, it is
important for the Royal Government of Bhutan to initiate an energy labeling program for commonly used
products such as lightings, geysers, refrigerator, air conditioners and washing machine or else initiate policy
measures so as to promote import and sale of only energy labeled products (products that have energy label of
other countries).
Based on the findings under this study and discussions with stakeholders and consumers in Bhutan, some S&L
policy options for appliances that can be considered are given below. The approximate saving potential has also
been indicated.
Table 30: Ranking of policy options for standards and labeling of appliances
S. No. S&L program options Consumers targeted Energy saving
potential (%)
1. Lighting* Institutional, commercial and domestic 30-40 %
2. Room heater* Institutional, commercial and domestic 10-20%
3. Water heaters (geyser)* Institutional, commercial and domestic 10-20%
4. Ceiling fan Institutional, commercial and domestic 20-30%
5. Air conditioner Institutional and commercial 20-30%
6. Rice cooker* Domestic and commercial (hotels and hospitals)
7. Refrigerator Domestic and commercial (hotels)
8. Heat pump Commercial and intuitional (new construction)
* indicates - most used appliances in Bhutan.
12.3. Energy Audits for different buildings in Bhutan
Energy audit is a very important exercise to gauge efficiency of energy consuming equipments and appliances in
buildings. Through this exercise, number of standard audit reports have been developed. The government can
decide voluntary or mandatory energy audits of buildings in Bhutan and can direct them to report their actions
to improve energy consumption.
12.4. Implementation of BEEC (Building Energy Efficiency
Code)
Based on the various assessments under this project it has been observed that most of the equipments being
used in buildings such as lights, geysers, rice cookers, refrigerators, ceiling fans and air conditioners are not
energy efficient and therefore needs replacement. Further, the usage of conventional materials, technology and
constructional practices is more dominant in the country and awareness on upcoming energy efficient
technologies, design and constructional requirements is lacking.
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Our understanding suggests that in Bhutan there is a huge potential for saving energy usage in buildings
through replacement of inefficient equipments with efficient ones and also through adoption of energy efficient
constructional practices.
The main components of building that are important from an energy efficiency aspect comprise building
envelope parameters (mainly covers construction practices such as fenestration, wall, roof, ceiling, window and
doors), electrical load (lighting, space heating, water heating, cooling and other load in office & kitchen section).
To make dramatic progress toward low-energy buildings in Bhutan, owners, designers and energy program
managers need prompt and meaningful information on these building and their performance components. The
information about these parameters facilitate in assessing the pattern of energy consumption. Eventually this is
then used to set a baseline of energy consumption and also to identify various probable energy saving
opportunities. The information pertaining to building specific energy efficiency practices is usually covered
under the BEEC.
The BEEC developed under this project comprise information on realistic opportunities to save energy and
GHG emissions from building sector at Bhutan. The BEEC is an important tool to improve energy efficiency in
new and existing buildings. The code set requirements for how energy-efficient a building will be. The code
hence is of utmost importance as it facilities following advantages.
Save consumers money,
Reduce pollution and increase reliability,
Protect consumers and ensure health and safety,
Provide quality and comfort,
Help consumers and builders make a cost effective investment,
Help improve long term sustainability.
It is recommended that the Royal Government of Bhutan shall introduce policies to initiate implementation of
practices prescribed in the code. The implementation of energy efficiency practices in the building sector is a
long term phenomenon and the policies shall target enforcement of EE measures in a phased manner.
12.5. Launch of program for efficiency of Bukhari system
In addition to electric room heaters the people in Bhutan also use firewood based Bukhari system for space
heating. Bukhari is used for burning firewood. It is a kind of wood stove which is found across Bhutan. The
firewood is usually sourced from hardwoods and softwoods depending upon the availability in different regions.
The usage of firewood is dominant in regions falling under alpine and mid-montana climatic zones such as
Bumthang, Trongsa and Thimpu etc.
The energy efficiency improvement in a firewood burning system can be divided in two aspects, following the
best practices while burning the firewood and selection of right stove (Bukhari). These have been explained
below.
To get the most out of firewood as fuel for space heating, it is important to properly dry (season) the wood.
Well-seasoned firewood will start easily and burn bright with little smoke.
Moreover, replacing the conventional wood stove with a more energy efficiently wood stove can save fuel,
money and protect the home occupant’s health. The conventional stoves (locally made) burn wood inefficiently
which wastes firewood, pollutes the air and creates dust inside the home. Newer stoves can reduce smoke and
Department of Renewable Energy, Ministry of Economic Affairs, Royal Government of Bhutan
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dust, as well as cut heating expenses. The Unites States Environment Protection Agency (US EPA) has initiated
certification of wood stoves so as to make it energy efficient and more safer for home usage.
The US government has initiated measures to enhance the know-how amongst the people to promote usage of
right kind of wood stoves and its usage in an efficient manner. The basic criterion of limiting the design of wood
stove is the emission level per kg of fuel wood. As per the present norm under US EPA qualified wood-burning
fireplace program the qualification criteria for wood stove is 5.1 g/kg66.
The qualification criteria indicated by the US EPA not only aims to improve the design and safety of wood
stoves but it is also a direct initiative to enhance the energy efficiency of the system by limiting the emission
level of gases such as carbon dioxide, carbon monoxide etc.
As per the US EPA program, following the guidelines pertaining to firewood burning practices and using the
right kind of wood stove can result in approximately 50% more efficient operation of wood stove and can limit
the use of firewood to 1/3 rd for the same heat. This will also result in 70% lesser emission of pollution.
In Bhutan, the usage of wood stoves is quite high in many areas of central and western parts. Introducing
programs for dissemination of information on burning practices and policies for bringing efficient stoves in
market can be very successful in terms of energy efficiency.
12.6. Initiate capacity building programs and strengthen
ongoing awareness programs
Capacity building is an iterative process of knowledge enhancement, learning, application and adjustment.
Realization of the energy efficiency improvement opportunities requires not only the strengthening of technical
and analytical aspects but also the behavioral aspects of building occupants and stakeholders.
The adoption of energy efficient norms in building sector is at a nascent stage and hence the stakeholders need
support for implementation of these opportunities. It is anticipated that transferring knowledge, skills and
know-how about building sector best practices in the field of energy management will be useful in large scale
adoption.
Considering building sector following are some significant capacity building activities that shall be
implemented in order to achieve desired energy efficiency goals.
Develop energy audit agencies in Bhutan
Initiate training programs for trainers (refers to energy sector stakeholders)
66 http://www.epa.gov/burnwise/testmethods.html#fireplace
Department of Renewable Energy, Ministry of Economic Affairs, Royal Government of Bhutan
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- To build their capacity for delivering the program objectives, and,
- Make them capable of imparting training to other stakeholders and consumers down the line.
Initiate training program for retailers and dealers so that they can promote energy efficient
products/materials in the market and can also make consumers aware about the benefits of such
products.
As a knowledge repository, develop standard implementation practices keeping local context in
consideration. The standard implementation practices shall refer to those energy efficiency measures
which can be simply put into practice in the upcoming buildings.
Build the capacity of local stakeholders to organize energy audits for
buildings more frequently.
The awareness building activities also forms a major part of capacity building
programs. Generally where the awareness on energy efficiency is poor the usage
of energy is high. The optimum usage of electrical components and facility has
the potential to bring significant energy savings. However, this requires
behavioural change in the people and facility occupants that can only be
achieved through continuous awareness of towards energy conservation. For
example, it is important to make the building occupants aware about switching
off the equipments when not in use so as to conserve energy.
As indicated earlier, the overall success of energy efficiency initiatives relies on
mass-adoption of measures in the society. Irrespective of the type of energy efficiency policy, implementation of
every policy shall be accompanied by an awareness and outreach campaign to provide information to the
consumers about the potential benefits.
The government should encourage better knowledge of energy efficiency dynamics and make the cost-saving
benefits of new practices and efficient technologies more visible in the public and private sectors. Some key
mediums for awareness and outreach program are shared below:
Information dissemination through print media and website about the benefits of energy efficiency
measures.
Imparting trainings or informative lectures on various subject specific modules designed to improve
performance of buildings.
Conducting workshops in association with policy makers to discuss and deliberate on emerging
technologies and building sector advancements.
Circulation of informative brochures and leaflets during trainings and workshops.
Dissemination of information through a link at the website of Ministry of Economic Affairs.
Sharing of case studies and success stories from implementation of such initiatives in other countries.
Audio and video
media
Print media
Flyer
Brochure
Website
Department of Renewable Energy, Ministry of Economic Affairs, Royal Government of Bhutan
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12.7. Energy efficiency policy requirements
Some of the key requirements pertaining to energy efficiency policies irrespective of the sector are shared
below. The energy efficiency policy will consist of the following aspects:
Strong analytic foundation,
Articulate purpose, goals and objectives,
Incorporate quantitative time-bound targets, both long term and short term,
Identify internal and external factors affecting success,
Be comprehensive and cross-sectoral,
Ensure integration with other national policy areas,
Identify the resources needed to turn strategy into action,
Priorities consuming sectors and policy measures,
Identify actions and assign responsibility,
Provide for results monitoring, updating and revisions,
Facilitate stakeholder engagement and build political consensus.
Several of the above already exist to some degree in energy sector policies in Kingdom of Bhutan and are likely
to need at least a little, if not major, bolstering in the form of technical recommendations to facilitate energy
efficiency policy development and an overall effective functioning.
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