the use of bim to analyse the energy performance of a retrofitted educational building in ireland -...

THE USE OF BIM TO ANALYSE

THE BUILDING ENERGY

PERFORMANCE OF A

RETROFITTED EDUCATIONAL

BUILDING IN IRELAND (Building and Civil Engineering Department – GMIT)

By

MARK THORNTON

B.SC. (HONS) IN ARCHITECTURAL TECHNOLOGY

A TECHNICAL REPORT SUBMITTED IN PARTIAL FULFILMENT OF THE REQUIREMENTS

FOR THE BACHELOR OF SCIENCE (HONOURS) IN ARCHITECTURAL TECHNOLOGY

GALWAY MAYO INSTITUTE OF TECHNOLOGY

2015

The use of BIM to analyse the building energy performance of a retrofitted educational building in Ireland

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Executive Summary

With global warming and climate change a major issue in today’s world, it is now more than ever

that a shift towards energy efficient buildings is needed. The construction industry consumes a large

amount of energy throughout the world and now measures are being taken to combat this. Within

Ireland, Technical Guidance Documents Part L 2008 Buildings other than dwellings and 2011

dwellings regulate how a building is designed for energy efficiency. These documents are to be

changed in 2015 to help push Ireland towards nearly zero energy buildings. These NZEB targets

come from the EU Directive 2010/31 and in place to help Europe reach nearly zero energy buildings

by 2020. The stricter regulations call for a primary energy use of 45 kWh/m2/annum for a new

building, 55-60 kWh/m2/annum and 125 to 150kWh/m2/annum for an existing building. The

Department of the Environment’s paper “Towards Nearly Zero Energy Buildings in Ireland 2012” and

“Statutory Instruments SI no 243 2012” looks at the how Ireland is to achieve the targets set out by

the EU by 2018.

With Building Information Modelling (BIM) becoming more prominent with in the construction

industry it opens up the possibilities to analyse the projected energy usage within a building at the

design stage. There are various building energy simulation software options available that can be

used with a BIM model. This report looks at using a Revit model with Integrated Environment

Solutions Virtual Environment (IES VE) or Autodesk Green Building Studio to perform an energy

analysis to get the total energy usage within the building to try and reach compliance with the NZEB

targets. A suitable software option is chosen and the analysis is performed with various design

options looked at and the results are compared and checked to see if any option complies with the

NZEB. The limitations of the software are looked at and the accuracy of the results is called into

question by being validated against similar research in the area of building performance simulation.


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Table of Contents

ACKNOWLEDGEMENTS ............................................................................................................................ i

LIST OF TABLES ......................................................................................................................................... i

LIST OF FIGURES ...................................................................................................................................... ii

LIST OF ABBREVIATIONS ........................................................................................................................ iv

SECTION 1.0 ............................................................................................................................................ 1

1.1 Introduction .................................................................................................................................. 1

1.2 Aim of the report .......................................................................................................................... 2

1.3 Objectives of the Report ............................................................................................................... 2

1.4 Scopes and limitations .................................................................................................................. 3

1.4.1 Scope of the report ................................................................................................................ 3

1.4.2 Limitations of the report ........................................................................................................ 3

SECTION 2.0 ............................................................................................................................................ 3

2.1 Methodology ................................................................................................................................. 3

2.1.1 Primary ................................................................................................................................... 3

2.1.2 Secondary ............................................................................................................................... 4

SECTION 3.0 Research ............................................................................................................................. 5

3.1 Secondary research ....................................................................................................................... 5

3.1.1 Irish Regulations for Building Energy Performance - Technical Guidance Documents ......... 5

3.1.2 NZEB – Nearly Zero Energy Buildings Targets for 2020 ......................................................... 6

3.1.3 Use of BIM and Building Performance Simulation Software in Energy Efficient Design ....... 8

3.1.4 Conclusion .............................................................................................................................. 9

3.2 Primary research ......................................................................................................................... 10

3.2.1 Building and Civil Engineering Department - GMIT ............................................................. 10

3.2.2 BIM model making process for energy analysis ................................................................... 11

3.2.1.1 Existing Building ............................................................................................................ 11

3.2.1.2 Proposed upgrade to existing Building ......................................................................... 12

3.2.1.3 Architectural model to analytical model: Preparation for analysis .............................. 13

3.2.1.4 Importing the model for analysis .................................................................................. 16

3.2.2 Renewable technologies ...................................................................................................... 16

3.2.2.1 Using BIM and analysis software for aiding renewable technologies decisions .......... 16

3.2.3 Selecting the HVAC Systems ................................................................................................ 19

3.2.3 Analysis ................................................................................................................................ 19


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3.2.3.1 Base Run results ............................................................................................................ 20

3.2.3.2 Air Source Heat pump results ....................................................................................... 23

3.2.3.3 Gas Condensing Boiler .................................................................................................. 26

3.2.3.4 Comparisons ................................................................................................................. 29

SECTION 4.0 Results .............................................................................................................................. 30

SECTION 5.0 Conclusions and Recommendations ................................................................................ 30

5.1 Conclusion ................................................................................................................................... 30

5.2 Recommendations ...................................................................................................................... 31

APPENDICES .......................................................................................................................................... 32

Appendix A: Plagiarism Declaration .................................................................................................. 32

Appendix B: Weather Data – Wind Roses ......................................................................................... 33

Appendix C: Base Run Costs .............................................................................................................. 34

Appendix D: Air Source Heat Pump Costs ......................................................................................... 35

Appendix E: Gas Condensing Boiler Costs......................................................................................... 37

Appendix F: Cost Comparison ........................................................................................................... 38

REFERENCES .......................................................................................................................................... 39

BIBLIOGRAPHY ...................................................................................................................................... 40


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ACKNOWLEDGEMENTS

This Technical Report would not have been possible without the support of many people. The author

wishes to express his gratitude to his supervisors; Irene Hayden and Siobhaun Cawley, lecturers in

GMIT, who were abundantly helpful and offered invaluable assistance, support and guidance. The

author would also like to convey thanks to his friends and classmates for their support throughout

the research and writing of this report. The author wishes to express a special thanks and gratitude

to his family and girlfriend for their understanding and endless support through the duration of his

studies.

LIST OF TABLES

Table 1: Total energy usage per month-Base run ................................................................................. 21

Table 2: total electricity usage per month-base run ............................................................................. 22

Table 3: fuel usage per month-base run ............................................................................................... 22

Table 4: Monthly usage for energy – Air Source Heat Pump ................................................................ 24

Table 5: monthly usage for electricity – air source heat pump ............................................................ 25

Table 6: monthly usage for fuel – air source heat pump ...................................................................... 25

Table 7: monthly usage for energy – gas condensing boiler ................................................................ 27

Table 8: monthly usage for electricity –gas condensing boiler ............................................................ 28

Table 9: monthly usage for fuel – gas condensing boiler ..................................................................... 28

Table 10: Total monthly and cost per m2 energy costs......................................................................... 34

Table 11: total monthly and cost per m2 electricity costs .................................................................... 34

Table 12: total monthly and cost per m2 fuel costs .............................................................................. 35

Table 13: total monthly and cost per m2 energy costs - air source heat pump .................................... 35

Table 14: total monthly and cost per m2 electricity costs - air source heat pump ............................... 36

Table 15: total monthly and cost per m2 fuel costs - air source heat pump......................................... 36

Table 16: total monthly and cost per m2 energy costs - gas condensing boiler ................................... 37

Table 17: total monthly and cost per m2 electricity costs - gas condensing boiler .............................. 37

Table 18: total monthly and cost per m2 fuel costs - gas condensing boiler ........................................ 38


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LIST OF FIGURES

Figure 1: Potential energy savings at the design stage. .......................................................................... 7

Figure 2: How BIM is used....................................................................................................................... 8

Figure 3: South Elevation of Galway Mayo Institute of Technology Building and Civil Engineering

Department ........................................................................................................................................... 10

Figure 4: Revit model of existing Building and Civil Engineering Department ..................................... 11

Figure 5: Revit model of the upgraded Building and Civil Engineering Department ............................ 12

Figure 6: Thermal image of heat loss through external wall at corner junction ................................. 12

Figure 7: Thermal image of heat loss through exterior wall ................................................................. 12

Figure 8: U-value calculation using u-wert.net for the existing external WALL ................................... 13

Figure 9: U-value calculation using u-wert.net for the proposed upgrade of the external wall .......... 13

Figure 10: Architectural model ............................................................................................................. 14

Figure 11: Analysis model ..................................................................................................................... 14

Figure 12: Architectural model interior ................................................................................................ 15

Figure 13: Analysis model interior ........................................................................................................ 15

Figure 14: Export settings using room .................................................................................................. 15

Figure 15: Weather data from green building studio ........................................................................... 17

Figure 16: Wind frequency distribution chart for 12 months showing wind speed in m2 and

percentage of time ................................................................................................................................ 17

Figure 17: Direct normal radiation frequency distribution chart ......................................................... 18

Figure 18: Photovoltaic potential from green building studio .............................................................. 18

Figure 19: examples of some of the HVAC systems available in Green Building Studio ...................... 19

Figure 20: Energy carbon and cost summary of Base run .................................................................... 20

Figure 21: carbon neutral potential ...................................................................................................... 20

Figure 22: Electrical power sources ...................................................................................................... 20

Figure 23: Annual electrical use within the building............................................................................. 21

Figure 24: Annual fuel end use ............................................................................................................. 21

Figure 25: monthly data for total energy usage – Base Run ................................................................. 21

Figure 26: monthly data for total electricity usage – Base Run ............................................................ 22

Figure 27: monthly data for total fuel usage – Base Run ...................................................................... 22

Figure 28: Energy carbon and cost summary using an air source heat pump ...................................... 23

Figure 29: carbon neutral potential using an air source heat pump .................................................... 23

Figure 30: annual fuel end use using an air source heat pump ............................................................ 24


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Figure 31: annual electrical use within the building using an air source heat pump ........................... 24

Figure 32: monthly data for total energy usage – air source heat pump ............................................. 24

Figure 33: monthly data for total electricity usage – air source heat pump ....................................... 25

Figure 34: monthly data for total fuel usage – air source heat pump .................................................. 25

Figure 35: energy carbon and cost summary using a gas condensing boiler ....................................... 26

Figure 36: carbon neutral potential using a gas condensing boiler ...................................................... 26

Figure 37: annual fuel end use using a gas condensing boiler.............................................................. 27

Figure 38: annual electrical use within the building using a gas condensing boiler ............................. 27

Figure 39: monthly data for total energy usage – gas condensing boiler ............................................ 27

Figure 40: monthly data for total electricity usage – gas condensing boiler ........................................ 28

Figure 41: monthly data for total fuel usage – gas condensing boiler ................................................. 28

Figure 42: total energy used (kwh/m2/annum) for each run compared to nzeb targets ..................... 29

Figure 43: winter and summer wind roses ........................................................................................... 33

Figure 44: annual wind rose chart showing wind direction along with the wind speed ...................... 33

Figure 45: total energy costs - base run ................................................................................................ 34

Figure 46: Total electricity costs - Base Run ......................................................................................... 34

Figure 47: total fuel costs - base run..................................................................................................... 35

Figure 48: total energy costs - air source heat pump ........................................................................... 35

Figure 49: total electricity costs - air source heat pump ...................................................................... 36

Figure 50: total fuel costs - air source heat pump ................................................................................ 36

Figure 51: total energy costs - gas condensing boiler ........................................................................... 37

Figure 52: total electricity costs - gas condensing boiler ...................................................................... 37

Figure 53: total fuel costs - gas condensing boiler................................................................................ 38

Figure 54: total energy cost per year for each design option ............................................................... 38


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LIST OF ABBREVIATIONS

BER: Building energy rating

BIM: Building Information Modelling

EED: Energy Efficient Design

GMIT: Galway Mayo Institute of Technology

HVAC: Heating Ventilation and Cooling

IESVE: Integrated Environmental Solutions Virtual Environment

KWh: Kilo watts per hour

KBtu: Kilo British Thermal Units

NZEB: Nearly Zero Energy Buildings

PV: Photovoltaic

TGD: Technical Guidance Document


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SECTION 1.0

1.1 Introduction

With climate change a major issue in today’s world there is a major shift towards more energy

conservation and reducing our carbon footprint.

"Buildings consume 40% of global primary energy and contribute to in excess of 30% CO2 emissions.”

(Costa, Keane et al. 2013).

These figures are very high proportion of total global energy use and carbon dioxide emissions and

contribute significantly to climate change. It is now more than ever that steps have to be taken to

reduce these figures. Within the construction sector steps are being taken to reduce the carbon foot

print and environmental impact when building, but a lot of this is being done in the design phase,

such as sourcing local materials to reduce transport costs, environmental impact statements which

are required prior to planning permission, and the use of various renewable technologies. A lot more

can be achieved in the early stages of the design stage with the use of Building Information

Modelling and various energy simulation software. This can be done as early as the concept and

sketch design stage from orientating the building to maximising the solar gain and sunlight as well as

deciding what type of HVAC system is used and where the energy is sourced.

The construction industry is now starting to grow again, it is now more than ever that there needs to

be a change in the way buildings are designed and build with bigger emphasis on enhanced energy

performance and energy conservation. There is also a large stock of buildings within Ireland that

have poor energy performance and are poorly constructed. This opens up an opportunity to address

this with retrofitting instead of new construction. When the recession hit it left a lot of unfinished

buildings in Ireland and these building can now be looked at to being completed instead of starting

new construction. There are also a lot of finished buildings that have a poor energy rating and

performance and retrofitting these buildings can also be looked at. The Irish government is now

looking at energy conservation with the revision of the Technical Guidance Document Part L –

Conservation of fuel and energy 2008 and 2011. One of the new revisions is that all buildings must

comply with a higher building energy rating (BER). This would mean that all new buildings must

comply with these new guidelines but if the same guidelines are followed when retrofitting a current

building the same rating and energy performance can be achieved.


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With the Building and Civil Engineering department in Galway Mayo Institute of Technology being

built in 1972, energy performance was not a major concern at the time and this then led to future

problems, mainly the poor energy performance with in the building and poor thermal performance.

The purpose of this report is to investigate the use of a Revit model and building performance

simulation software, like Autodesk Green Building Studio and Integrated Environmental Solutions

Virtual Environment to analyse the overall energy performance of a proposed retro fit of an

educational building in Ireland as a case study of Building and Civil Engineering Department in

Galway Mayo Institute of Technology, a wing of the original 1972 GMIT building.

1.2 Aim of the report

The aim of this report is to investigate how the use of a BIM model and building performance

simulation software such as Autodesk Green Building Studio and Integrated Environmental Solutions

Virtual Environment can be used to analyse the energy performance of a proposed retro fit of an

educational building in Ireland as a case study. The report will look at the chosen software and the

advantages and limitations associated with it when running the simulations, while also looking at the

accuracy associated with this sort of simulation. The results will aim to comply with Technical

Guidance Document Part L - Conservation of Fuel and Energy – Dwellings (2011) and NZEB targets.

The building that will be used is the Building and Civil Engineering Department in Galway Mayo

Institute of Technology.

1.3 Objectives of the Report

1. To Analyse the energy performance and Technical Guidance Document Part L 2011 and

NZEB compliance as a case study of an upgraded educational building using BIM software

(Revit) and building energy performance simulation software

2. Compare findings and limitations of the software and analyse the accuracy of the results.


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1.4 Scopes and limitations

1.4.1 Scope of the report The scope of this report aims to use a BIM model produced from Revit which was produced in

conjunction with a Design and Detail project. The model shows the upgraded elements of the

Building and Civil Engineering Department of Galway Mayo Institute of Technology and is to be used

as a case study for the building energy performance analysis using Autodesk Green Building Studio

and Integrated Environmental Solutions Virtual Environment. Various Heating Ventilation and

Cooling systems (HVAC) will be analysed by the software and the output will be analysed and

compared and compliance with current building regulations will checked along with the accuracy of

the results from the simulation software.

1.4.2 Limitations of the report The limitations of this report will be the various software options that need to be looked at and the

time frame for the completion of the report. There will also be a learning curved associated with all

the software which could be a limitation of this report. Another limitation would be the speed of the

process associated with the analysis and reliance upon the results to prove compliance.

SECTION 2.0

2.1 Methodology

2.1.1 Primary

A Revit model was completed of the proposed upgrade of the Building and Civil Engineering

Department of GMIT as a case study. Then 3 different runs for analysis were done with different

HVAC systems and renewable technologies. The 3 runs were;

1. Base Run – analysis of just the upgraded envelope of the building and boiler

2. Air source heat pump– analysis with an air source heat pump with renewable technologies

3. Gas Condensing Boiler – analysis with a gas condensing boiler and renewable technologies

A fourth run was to be done using a bio mass boiler but due to limitations in the software this was

not achievable.

Various building performance software like Autodesk Green Building Studio and Integrated

Environmental Solutions Virtual Environment were looked at for the analysis.


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Autodesk Green building studio is a cloud based service that allows for building performance

simulations. It can be used as a standalone web service or linked to a Revit model for whole building

energy analysis. It is designed to simplify the task of whole building performance analysis and looks

at energy use, water use and carbon emissions

The second option was Integrated Environmental Solutions Virtual Environment (IESVE). IESVE is a

software suite that with 2 options, one for architects and one for engineers. For this report it will be

looking at VE (virtual environment) for architects. The package is fully compatible with sketch up and

all BIM packages including Revit. Just like green building studio it does analysis for solar, shading and

lighting. It also does analysis for energy usage, thermal analysis, heating/cooling and ventilation and

air flow while also provide costs.

With all the options looked at and analysed the results were gathered and compared to see if they

comply with the current building regulations or the nearly zero energy building targets for 2020 and

a conclusion was reached. The software will be analysed for accuracy of results and be validated

against other peer reviewed papers which looks at the same subject. These papers are; “Validation

of building energy modelling tools: Ecotect, Green Building Studio and IES VE” (Reeves, Olbina et al.

2012) and “Assessing the Operational Energy Profiles of UK educational buildings: findings from

detailed surveys and modelling compared to consumption”. (Knight, Stravoravdis et al. 2007)

2.1.2 Secondary

Research was done into the area of Irish building regulations which are Technical Guidance

Document Part L Conservation of Fuel and Energy – Dwellings (2011). This research looked at the

regulations in place and the minimum requirements that needed to achieve compliance. Various

peer reviewed publications which looked at building energy performance and how Building

Information Modelling and computer software can be used to analyse building energy performance

at a design stage were looked at. The government’s paper entitled “Towards nearly zero energy

buildings in Ireland – Planning for 2020 and beyond” (Dept. of Environment 2012) and the “Statutory

Instruments S.I. No. 243 of 2012” (Government of Ireland 2012) which is the Laws that are enforce

the regulations. These look at BER certifications along with energy systems. Building Information

Modelling in general is researched and the impact it has upon building energy performance analysis.


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SECTION 3.0 Research

3.1 Secondary research

3.1.1 Irish Regulations for Building Energy Performance - Technical Guidance

Documents

In Ireland building energy performance is mainly regulated under the Technical Guidance Document

Part L - Conservation of fuel and energy Buildings other than dwellings 2008 and dwellings 2011, but

Technical Guidance Document Part F – Ventilation 2009 and Technical Guidance Document Part J –

heat producing appliances 2014 also influence the energy performance of a building. There are 2

different TGD part L, one from 2008 which focuses on buildings other than dwellings and TGD part L

2011 which focuses on dwellings. The current regulations for part L for both dwellings and buildings

other than dwellings are being revised and expected to be released in 2015. For the purpose of this

report the main focus will be on TGD Part L Conservation of fuel and energy – Dwellings 2011, as

they are the more up to date regulations for energy performance within a building. Although they do

not strictly relate to commercial buildings it is good practice to apply these regulations for all

buildings to reach a desired level of energy performance. The report will also be looking at some of

the proposed changes to the current regulations to help Ireland achieve its NZEB (nearly zero energy

buildings) target, which the government set for set for 2018 (Smyth 2014) and how it would be good

practice to aim for these targets even though they are currently not enforced yet. This would mean a

higher level of energy performance within the building and provide more sustainable buildings.

Technical guidance document part L 2011 conservation of fuel and energy mainly focuses on new

buildings but it also regulates existing buildings too. Since this report is based on a retrofit of a

current building it will be looking at the regulations that apply to existing buildings but it is also good

practice to aim for as high a building energy performance as possible. The TGD Part L 2011

requirement in says that;

All buildings have to be designed and constructed to make sure that the energy performance of the

building is “such as to limit the amount of energy required for operation” and also reduce the

amount of carbon dioxide emission. The next section, L2 is the requirements for existing buildings

and states that the building has to limit heat loss and maximise heat gain through the fabric of the

building. The output from the space heating and hot water has to be controlled “as appropriate” and

all heat loss should be limited from pipes, ducts, and vessels for transport of heated water or air are


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limited. It also states that any gas or oil fired boilers have an efficiency of 90% “where practicable”

(TGD Part L 2011)

This would mean, in terms of design that the careful consideration should be taken when it comes

to the energy performance within the building and to try and reduce as much energy as possible that

is required to run the building. The design of the building can impact this greatly with the choice of

building materials that should be used and the performance value of each material. Calculations

must also be done reach the desired level of energy performance and U-values that are required to

meet the regulations. U-Values are the measure of heat loss from a building element like a wall or

roofs. It measures how well each building element transfers heat. The higher the U-Value the worse

the thermal performance of the envelope is. TGD L 2011 sets out minimum u-value that need to be

achieved to comply with the regulations and each building element like the walls and roofs have

specific minimum u-value that each building has to achieve to comply. TGD part L 2011 has backstop

elemental U-Values of 0.21W/m2K for floors, walls, roofs and soffits, whereas the guidance from Des

Murphy (Chartered Engineer) at a recent engineers Ireland talk suggested that a target of 0.15

W/m2K might be more realistic to achieve compliance with TGD part L. (Murphy 2014)

Another area of building energy performance would be services within the building. This is also

looked at with TGD part L 2011 and it states that any oil or gas fired burners should have an

efficiency of 90%. (TGD Part L 2011). Ventilation is another area that needs to be looked at and

mechanical ventilation should be limited where possible, with passive ventilation incorporated

instead. This would mean that less energy is used to run these services and thus would help with the

overall building energy performance of the building. All these factors must be taken into account

when retrofitting a current building, and with the current changes to our regulations to get Ireland

to reach the NZEB (nearly zero energy buildings) target set for 2020 it is now more than ever that

good design and planning must be implemented at an early stage.

3.1.2 NZEB – Nearly Zero Energy Buildings Targets for 2020

“A total of 12.6 million tonnes of CO2 equivalent was generated by the building sector in Ireland in

2010. This accounted for 28.8% of 2010 non-ETS emissions” (Dept. of Environment 2012).

These figures show the amount of CO2 that is produced by the building sector in Ireland and shows

that there is a need to move towards more sustainable and green building. The targets set out that

a building should achieve a BER (building energy rating) of A3 or higher which equates to a primary


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energy uses of 45kWh/m2/annum1. There are also targets set out for educational buildings which is

55-60 kWh/m2 1 but these targets are intermediate targets and will be assessed even more in the

revised TGD L 2014. The NZEB for existing buildings on the other hand isn’t very high with target set

out for BER rating of C1 or higher which equates to 125 to 150kWh/m2/annum1 but also states that a

“reasonable” proportion of the energy used be sourced from a renewable sources where as in a new

building would equate to 22% of the energy used in a building be from renewable sources of

energy1.

The current technical guidance

documents for energy performance are

being revised to make sure that all new

buildings comply with a better

standard of energy performance and

help Ireland reach these targets and

reduce CO2 emissions. It is now more

than ever that all steps need to be

taken in the construction industry to

help achieve these targets. The report,

“towards nearly zero energy buildings in Ireland planning for 2020 and beyond” by the department

of the environment, community and local government also looks at how energy savings can be

achieved at the design stage. The graph in Fig. 4 shows how much energy savings can be achieved.

The graph also looks at how much investment is need at each stage of the life of a building and it is

clearly seen that there is very little investment needed at the design stage as compared to each

other stage of the building. “As well as being more cost-effective, it is also easier if energy efficiency

is integrated into capital projects from the outset.” (Dept. of Environment 2012) The report also

pushes for Energy Efficient Design (EED) which means that the construction and the management of

buildings should consume as little energy as possible during the operation of the building. EED lets

you save money by reducing energy use within the building and this is where BIM and building

performance simulation software can be a major advantage in building design and save money and

energy in a project. These targets and methodology set out in the NZEB targets mainly apply for new

builds but this report aims to show how these targets and energy savings can be achieved when

retrofitting an existing building with poor energy performance and how these savings can be shown

as early as the design stage.

1 DEPT OF ENVIRONMENT, 2012. TOWARDS NEARLY ZERO ENERGY BUILDINGS IN IRELAND.

FIGURE 1: POTENTIAL ENERGY SAVINGS AT THE DESIGN STAGE. (DEPT. OF

ENVIRONMENT 2012)


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3.1.3 Use of BIM and Building Performance Simulation Software in Energy

Efficient Design

Over the last decade building information modelling (BIM) has been more influential within the

construction industry throughout the world. Traditionally when designing a building 2D drawings

usually drafted in AutoCAD are used throughout the design and construction phase. With BIM a 3D

model is used and the one model is shared and collaborated on with everyone involved within the

construction of a building from structural engineer, architect, contractors etc. It can used to help

schedule and manage projects and energy analysis on a building.

FIGURE 2: HOW BIM IS USED

Source: http://www.directionsmag.com/articles/why-we-care-about-bim/368436


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With the world more aware of climate change and the construction industry producing a large

percentage CO2 building professionals are looking more at sustainable building and better energy

performance. The Irish government has addressed this issue with the NZEB targets for 2020 (refer to

section 3.1.3) and BIM can used to help reach these targets.

“Quality sustainable design requires an understanding of how a building will perform after it's built,

which in turn requires computer-based simulation software for rigorous building analysis”(Rundell,

Rick 2007) What Rundell refers to is that we need to look at a building in terms of its operation and

the energy used over its life. In the past sustainable design was just an “interesting idea” (Rundell,

Rick 2007) but now the focus is on nearly zero energy buildings which means that we have to use

less energy in the operation of the building. BIM allows us to do this by producing an accurate virtual

model of the building with the correct information and running it through an energy analysis

software, but there are a lot of factors that have to be looked at to produce accurate results. HVAC

system, location and weather patterns all have to be looked (Mustafaraj, Marini et al. 2014).

Mustafaraj argues that there are drawbacks to computer simulations like the amount of detailed

data and time that is required and that it might not be cost effective and that this area is a

specialised area of building design. The integration of BIM models, and various building performance

simulation software addresses this issue - “providing an easy way for architects and engineers to

examine the implications of alternative design strategies, helping them achieve higher operational

efficiency and building performance” (Rundell, Rick 2007). This integration means various design

options can be looked at by the designer at an early stage and give you indication of the future

building performance. With the Irish government targeting nearly zero energy buildings which

influences the changes to the current technical guidance document part L it means that designers

must look at building performance at an early stage in the design. The growing use of BIM within the

construction industry gives designers that option by linking them to various building performance

software and providing with various options at an early stage and implement them in the

construction phase. This report looks at how this approach to building performance analysis and

sustainable design can be applied to a retrofit of an existing building by linking a Revit model to 2 of

these software options and how it can produce the desired results to comply with the targets set out

in the NZEB.

3.1.4 Conclusion

With all the research gathered and building energy performance investigated it is clear to see there

needs to be a major shift towards a higher standard of building going forward. With the changes to

the current TGD Part L 2008 and 20011 which are due in 2015, there will be a major influence on

building energy performance. These regulations are being introduced to push Ireland towards its


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2018 target of nearly zero energy buildings by introducing that all buildings must receive a higher

Building Energy Rating of A3 or higher. With BIM becoming more and more influential in

construction this creates an opportunity for designers to analyse the projected building energy

performance of a building in the design stages. For this report a Revit model of the upgraded Galway

Mayo Institute of Technology is used along with Green Building for analysis. Green Building Studio is

to be used due the built in compatibility with Revit and that it is a cloud base software that allows

for safe storage and fast analysis of results. The results from the primary research will be compared

and checked against the NZEB targets and at a minimum the current building regulations to check

for compliance while the accuracy of the analysis needs to be validated.

3.2 Primary research

Case Study: Building energy performance analysis of a proposed retrofit of

GMIT Building and Civil Engineering Department

3.2.1 Building and Civil Engineering Department - GMIT

FIGURE 3: SOUTH ELEVATION OF GALWAY MAYO INSTITUTE OF TECHNOLOGY BUILDING AND CIVIL ENGINEERING DEPARTMENT

(AUTHORS OWN SEPT 2014)


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FIGURE 4: REVIT MODEL OF EXISTING BUILDING

AND CIVIL ENGINEERING DEPARTMENT

Galway/Mayo Institute of Technology (GMIT) is located on the approach road to Galway City, along

the Dublin Road. The campus dates back to the 1970’s and reflects the standard regional technical

college built in Ireland at that time, with pre-cast concrete cladding panels combined with

aluminium framed windows.

The Engineering Department is located in the 1972 building which is a precast concrete structure

with blockwork internal walls. The external walls consist of block work with cavity and precast

concrete infill panels with a pebble dash. The windows are single glazed aluminium. The proposed

link bridge is to connect to the 1974 which is opposite the Engineering department and is of the

same construction. There have been very little alterations to the 1972 building with insulation added

to the roof and new escape stairs constructed in 2013 on the west façade. This type of construction

from the 70s is common in all of the original RTCs in the country and energy efficiency and any

architectural merit wasn’t considered at the time. There is a lot of heat loss and even over heating in

the building during the summer due to the large glazing on the south faced and the windows being

just single glazed means a lot of heat is lost. There is also very little to no insulation in the external

walls which also leads to a lot of heat loss and can be very uncomfortable for the occupants

throughout the year.

3.2.2 BIM model making process for energy analysis

The first stage of any BIM process is to produce a BIM model of the project, in this case GMIT

building and Civil Engineering Department. As stated in section 3.1.4.1 various modelling software

options can be used to produce the model. In this report Autodesk Revit was used to produce the

model.

3.2.1.1 Existing Building

A survey was carried out on the existing Building and Civil

Engineering Department and the existing building was

modelled using Revit. This model was used to produce

floor plans and sections that would later help with the

design of a proposed link bridge that is to be connected to

the tourism and arts department which is located directly

across from Building and Civil Engineering Department.


12

3.2.1.2 Proposed upgrade to existing

Building

It was decided at an early stage that

energy performance was to be a major

factor in the upgrade of the existing

building. The building envelope is one of

the main issues for poor performance and

major heat loss in the building which can

be seen in Fig. 7 and Fig. 8, it was decided

that a major upgrade of the envelope was

needed first to help achieve a good level of energy performance. This should always be the first

thing to consider when looking at energy performance of a building. If the heat is escaping through

the fabric of the building then it will take a lot more energy to heat the building and will drastically

affect the energy performance of the building. Various options for how to insulate the building were

looked at along with various insulations and it was decided that an external insulation. U-Value

calculations were done with U-Vert.net which calculated the u-values for the existing and the

proposed upgrade of the external elements. These results can be seen in Fig.9 and Fig.10. These u-

values along with the help of “insulation continuity and airtightness in construction” (Thornton 2014)

allowed for the input of the thermal performance of each of the external elements of the upgrade

BIM model. With the findings of the report the thermal properties of each of the elements were

inputted into the new BIM model to give a more accurate representation of each material and thus

more accurate energy analysis. The current BIM model was then upgraded to the new proposed

model which included the revised room layouts and extension and link bridge.

FIGURE 5: REVIT MODEL OF THE UPGRADED BUILDING AND CIVIL

ENGINEERING DEPARTMENT

FIGURE 6: THERMAL IMAGE

OF HEAT LOSS

THROUGH

EXTERIOR WALL

(AUTHORS OWN

IMAGE

02/2015)

FIGURE 7: THERMAL

IMAGE OF HEAT

LOSS THROUGH

EXTERNAL WALL

AT CORNER

JUNCTION

(AUTHORS OWN

IMAGE

02/2015)


13

FIGURE 9: U-VALUE CALCULATION USING U-WERT.NET FOR

THE PROPOSED UPGRADE OF THE EXTERNAL WALL

(THORNTON 2014)

FIGURE 8: U-VALUE CALCULATION USING U-WERT.NET FOR THE

EXISTING EXTERNAL WALL (THORNTON 2014)

Figure 6 and Figure 7 show thermal images taken by the author of this report showing the heat loss

through the fabric of the building. This demonstrates the importance of a good insulation on the

external which will minimise heat loss and thus minimise the use of energy used in the building.

3.2.1.3 Architectural model to analytical model: Preparation for analysis A BIM model must be simplified in preparation for analysis. This is particularly important when using

IES VE for analysis, as a complex model can cause problems with integration. It is recommended to

keep the model as “lean” as possible as not to cause problems when, either importing it into the

software or using the IES VE Revit add on.

Figure 10 and Figure 11 shows the difference in the model when it comes to the building envelope.

The architectural model has a stacked wall with different cladding on different levels. This has to be

disregarded and a single wall be used. The complex roof light is also replaced with a standard family

along with the windows as it is recommended to use standard families when constructing the model.


14

FIGURE 10: ARCHITECTURAL

MODEL

FIGURE 11: ANALYSIS MODEL

The interior of the model must also be free of any furniture and extra families. This cuts down on the

size of the model when exporting it and makes it less complex, especially when using IES VE.

Figure 12 and Figure 13 shows the difference in the interior of the model when the furniture is all

taken out. The reasoning behind this is that the furniture and families are not needed when running

an analysis only the interior walls are required to enclose the space that is needed to tag the rooms.


15

FIGURE 12: ARCHITECTURAL

MODEL INTERIOR

FIGURE 13: ANALYSIS MODEL

INTERIOR

FIGURE 14: EXPORT SETTINGS USING ROOM

The next stage in the preparation stage is to apply rooms or spaces to the model. This calculates the

volume of each room and the spaces allow for the calculation of the volumes for the use of HVAC. It

is at this stage it can be seen why a basic model is required as all that is needed is to have various

elements that enclose a room like floors, walls, ceilings, columns and roofs.

Figure 14 shows the export

settings that are required for an

analysis. It is also at this stage that

the location and building type is

selected as highlighted in red. The

same procedure is used when

using spaces and the exported file

is a gbXML file that is then ready

to be imported in to Green

building studio or IES VE.


16

3.2.1.4 Importing the model for analysis When it came to importing the model into the software there were no issues regarding Green

Building Studio. Unfortunately when importing the model to IES VE big issues arose regarding

compatibility and this even arose with the add on for Revit. IES VE was having compatibility issues

regarding the model even though it imported correctly but at later stages an error arose. This

unexplained error stopped any analysis from continuing.

With the time constraints on this report there was no time to find a solution and the steep learning

curve involved in IES VE meant that Green Building Studio was chosen to run the analysis.

3.2.2 Renewable technologies

As stated in section 3.1.3 it is states that a “reasonable “amount of energy used be sourced from

renewable technologies. (Dept. of Environment 2012) This section of the reports looks at the various

types of renewable technologies selected to be incorporated within the proposed retrofit of the

building. The technologies were selected with the aid of IES VE and Green Building Studio analysis.

3.2.2.1 Using BIM and analysis software for aiding renewable technologies decisions After the BIM model is completed the next stage is to start the analysis. When importing the model

either within IES VE stand-alone software or the Revit add-on it allows for the option to analyse the

climate. One of the major issues within the IES VE software is that there is an issue with weather files

and selecting the location of the building. The nearest location is Claremorris which is 61.8 Km from

the actual proposed building location. There is also an issue when it comes to the weather file that is

used, with weather file used is Dublin89.fwt which is located in Dublin which is 208km from the site.

This can call into the accuracy of the climate results.

Within Green building studio there is a larger selection of weather files and in this case the nearest

weather file is located 7.2 km from the project. This gives a more accurate reading and can influence

the design options and in this case the use of renewables is influenced.


17

FIGURE 16: WIND FREQUENCY DISTRIBUTION

CHART FOR 12 MONTHS SHOWING WIND

SPEED IN M2 AND PERCENTAGE OF TIME

WIND: The weather data produces a wind roses (see Appendix A) and wind frequency chart that

allows the user to determine if a wind turbine could be an option on the site. It doesn’t take into

account any sort of obstructions due to not factoring in the actual model and surrounding area. For

this report and retro fit no wind turbine will be assessed as there is currently one located on site.

SOLAR: The data collected from the Green Building Studio also looks at solar radiation. It gives charts

that show the direct normal radiation frequency distribution and direct normal radiation cumulative

distribution for a 12 month period and also a seasonal period like summer and winter. (See Appendix

A)

These charts influence the design in terms of window sizes, photovoltaic panels and solar thermal

panels. For this report solar thermal panels and photovoltaic panels will be looked at to help reduce

energy consumption within the building.

FIGURE 15: WEATHER DATA FROM GREEN BUILDING STUDIO, LOCATED 7.2 KM FROM SITE


18

FIGURE 17: DIRECT NORMAL RADIATION

FREQUENCY DISTRIBUTION CHART WHICH

SHOWS HOW MUCH DIRECT SUN LIGHT IS

AVAILABLE OVER A 12 MONTH PERIOD

FIGURE 18: PHOTOVOLTAIC

POTENTIAL FROM GREEN BUILDING

STUDIO

Photovoltaic Panels and Solar thermal: Photovoltaic panels are used to convert solar radiation to

into electricity while solar thermal panels convert that solar energy for hot water. There are many

photovoltaic panels out on the market ranging in different prices and efficiency. These panels only

work in areas a lot direct sunlight as the convert the sunlight to direct current electricity. In IES VE

the analysis allows for the desired technical data to be inputted into software, but due to

compatibility issues regarding the model an analysis couldn’t be completed. Within Green Building

Studio the analysis allows for the use of PV panels in the design and also suggests how much

potential there is for PV panels.

An issue regarding solar panels in Green Building Studio is that the data is calculated on the

assumption that areas not considered opens E.g. Windows, doors and skylights can be used for solar

panels. The costs are also a default standard rate from Green Building Studio.


19

FIGURE 19: EXAMPLES OF SOME OF THE HVAC SYSTEMS AVAILABLE IN GREEN BUILDING STUDIO

3.2.3 Selecting the HVAC Systems

When it comes to deciding on an HVAC system Green Building Studio has set list to choose from. The

size of the list differs depending on size of the project from small to large projects. The list changes

in quantity and HVAC types depending on the size and number of stories within the project. This

feature allows the user to navigate the systems more freely but there also the disadvantage that a

specific brand or specifications from a specific brand cannot be inputted into the project. But since

the energy analysis is done at the design stage, specifically an early stage of the design and the HVAC

might not be finalised this isn’t an issue and can help with the decision on a type of HVAC system.

The issue could arise when these decisions are made and the energy output needs to be calculated

then.

For the analysis 3 types of HVAC systems were chosen and ran through green building studio for

analysis. The first was an air source heat pump and the second was a gas condensing boiler and the

third is a biomass boiler. Manufactures were looked at and the specs analysed and the closet type

from the suggested list from Green Building Studio was selected. The results can be seen in section 5

of this report.

3.2.3 Analysis

The model is then run through Green Building Studio and a base run was completed first which gave

a set of results that can be measured against. Alternative runs were created, as stated in Section

2.1.1 Primary Methodology of this report and the results were compared and are outlined in this

section. The fuel used in the analysis is natural gas.


20

FIGURE 21: CARBON NEUTRAL POTENTIAL

FIGURE 20: ENERGY CARBON AND COST SUMMARY OF

BASE RUN

FIGURE 22: ELECTRICAL POWER SOURCES

3.2.3.1 Base Run results

The base model with the upgraded fabric was run through Green Building Studio and the following

results were achieved.

Figure 20 shows a breakdown and a summary of

the carbon emission per year. It also simplifies the

results by comparing the emissions to SUV

equivalent. This feature is allows for people that

aren’t familiar with carbon emissions to grasp how

much CO2 are produced by a building each year.

The areas highlighted in red are the main areas that

need to be reduced to help reduce the buildings

energy usage and head towards NZEB targets

Figure 21 looks at the carbon neutral potential that

can be achieved by looking at design alternatives.

Figure 22 shows the electricity sources that are

available in the region. This looks at the potential

amount of power electrical that can be sourced. This

can be sourced from fossil fuel burning power plants

and it also looks at the potential for renewables.


21

FIGURE 23: ANNUAL ELECTRICAL USE WITHIN THE BUILDING FIGURE 24: ANNUAL FUEL END USE

FIGURE 25: MONTHLY DATA FOR TOTAL ENERGY USAGE – BASE RUN

Figure 23 Break down of the annual electrical use with lights and equipment using the most

electricity within the building.

Figure 24 Break down of the annual fuel use in the building. Space heating uses the most due to the

fact it is a gas boiler with in the building.

Energy usage

Figure 25 and Table 1 show the energy usage from the base run and it can be seen that space

heating consumes a lot of the energy with an average energy consumption of 66.83% over the

course of the year.

Month Energy usage KW/h

January 243571 KW/h February 222625 KW/h March 230116 KW/h

April 168785 KW/h

May 129223 KW/h

June 78152 KW/h July 64938 KW/h August 79223 KW/h September 79236 KW/h October 127845 KW/h November 193320 KW/h December 220662 KW/h

TABLE 1: TOTAL ENERGY USAGE PER

MONTH-BASE RUN

KWh


22

FIGURE 27: MONTHLY DATA FOR TOTAL FUEL USAGE – BASE

RUN

KBtu

FIGURE 26: MONTHLY DATA FOR TOTAL ELECTRICITY USAGE – BASE

RUN

Electricity Usage

Figure 26 and Table 2 show the electricity used from the base run and it can be seen that lights and

miscellaneous equipment that’s using the majority of the electricity throughout the year. There also

is a slight drop in the summer months due to the fact the operational hours of the building are

reduced.

Fuel Usage

Month Electricity usage KW/h


April 33632 KW/h

May 32633 KW/h


TABLE 2: TOTAL ELECTRICITY USAGE PER

MONTH-BASE RUN

Month Fuel usage kBtu

January 697653 kBtu February 637595 kBtu March 651129 kBtu

April 461161 kBtu

May 329578 kBtu

June 157151 kBtu July 101681 kBtu August 161184 kBtu September 171632 kBtu October 327544 kBtu November 542160 kBtu December 627061 kBtu

TABLE 3: FUEL USAGE PER MONTH-BASE RUN

KWh

KBtu


23

FIGURE 29: CARBON NEUTRAL POTENTIAL USING AN AIR

SOURCE HEAT PUMP

FIGURE 28: ENERGY CARBON AND COST SUMMARY USING

AN AIR SOURCE HEAT PUMP

Figure 27 and Table 3 show the fuel usage for the base run. Again it is clearly seen that the majority

of the fuel is being used for space heating, on average of 86.83% used for heating and the rest for

hot water. The winter months using up to 3 times as much fuel and there is a significant fall in fuel

usage during the summer months for space heating.

Costs

The cost of the energy, electricity and fuel usage can be seen in Appendix B. These costs are based

off the default costs in Green Building Studio and aren’t an accurate reflection on true cost of the

energy used in the building. The default costs don’t have to be used if the cost of electricity and fuel

per unit is known. These values can be entered at the start of project but cannot be changed after

that.

3.2.3.2 Air Source Heat pump results

A second run of the model was then put through

Green Building Studio using an air source heat pump

for space heating. Since the program has limited

amount of HVAC systems and doesn’t allow for

picking a specific one the closet possible pump in

relations to specifications was chosen.

Figure 28 shows there is a significant drop in the

energy use intensity and fuel but there is an increase

in electrical use. This is because the heat pump uses

electricity to operate.

Figure 29 shows the carbon neutral potential and

also compares the annual CO2 emissions with the

base run and a significant difference can be seen.

The electrical power source remains the same as

seen in Figure 22, Section 3.2.3.1.


24

FIGURE 32: MONTHLY DATA FOR TOTAL ENERGY USAGE – AIR SOURCE

HEAT PUMP

FIGURE 31: ANNUAL ELECTRICAL USE WITHIN THE BUILDING

USING AN AIR SOURCE HEAT PUMP

Figure 31 shows the annual electrical usage with an air source heat pump. It can be seen that 23.7%

of the total electrical use is now being used by space heating as compared to 12.5% being used in

the base run. The fuel usage drastically changes

with the air source heat pump which can be seen

in figure 30 with 100% of the fuel usage being

used for hot water rather than space heating.

Energy usage



April 58528 KW/h

May 52082 KW/h


TABLE 4: MONTHLY USAGE FOR ENERGY –

AIR SOURCE HEAT PUMP

KWh

FIGURE 30: ANNUAL FUEL END USE USING AN AIR SOURCE

HEAT PUMP


25

FIGURE 34: MONTHLY DATA FOR TOTAL FUEL USAGE – AIR SOURCE

HEAT PUMP

FIGURE 33: MONTHLY DATA FOR TOTAL ELECTRICITY USAGE – AIR

SOURCE HEAT PUMP

Figure 32 and Table 4 show the energy if an air source heat pump was used and it can be seen that

space heating consumes a lot less energy than the base run.

Electricity Usage

Figure 33 and Table 5 show the electricity use when an air source heat pump is used. It can be seen

that space heating uses more electricity than the base run and overall more electricity is used. This

still doesn’t affect the overall energy use which can be seen in figure 32 and table 4 when compared

to section 3.2.3.1, figure 25 and table 1.

Fuel Usage



April 47327 KW/h

May 40930 KW/h


TABLE 5: MONTHLY USAGE FOR ELECTRICITY – AIR

SOURCE HEAT PUMP



April 38220 kBtu

May 38052 kBtu


TABLE 6: MONTHLY USAGE FOR FUEL – AIR

SOURCE HEAT PUMP

KBtu

KWh


26

FIGURE 35: ENERGY CARBON AND COST SUMMARY USING A

GAS CONDENSING BOILER

FIGURE 36: CARBON NEUTRAL POTENTIAL USING A GAS

CONDENSING BOILER

Figure 34 and Table 6 show the fuel usage for an air source heat pump. This run clearly shows that

the all of the fuel is being used for hot water. The fuel usage is fairly consistent throughout the year.

There is also a significant drop in fuel usage when compared to the base run and this is seen when

the figures are compared to section 3.2.3.1 figure 37 and table 3.

Costs

The cost of the energy, electricity and fuel usage can be seen in Appendix E.

3.2.3.3 Gas Condensing Boiler The third run was made with the intention of using a

gas condensing boiler. Like the air source heat pump

the choices of HVAC systems were limited. A boiler

was selected with the closest specifications to the

boiler and also with a very high efficiency. The

boiler used had 95% efficiency.

Figure 35 shows that there is an increase in the

energy demand when using a gas condensing boiler

when compared to the air source heat pump.

Figure 36 shows the carbon neutral potential and

also compares the annual CO2 emissions with the

base run and again a difference can be seen.

The electrical power source remains the same as

seen in Figure 22, Section 3.2.3.1.


27

FIGURE 38: ANNUAL ELECTRICAL USE WITHIN THE BUILDING

USING A GAS CONDENSING BOILER

FIGURE 39: MONTHLY DATA FOR TOTAL ENERGY USAGE – GAS

CONDENSING BOILER

Figure 38 shows the annual electrical use when using a gas condensing boiler. It can be seen that less

electricity is now being used when using the boiler when compared to the heat pump. The fuel

usage again changes with a gas condensing boiler which can be seen in figure 37 with 89.6% of the

fuel usage being used for space heating and the remainder used for hot water. There is very little

change in the fuel usage when compared to the base run which is 91% being used for space heating.

Energy usage



April 131555 KW/h

May 99812 KW/h


TABLE 7: MONTHLY USAGE FOR ENERGY – GAS

CONDENSING BOILER

KWh

FIGURE 37: ANNUAL FUEL END USE USING A GAS

CONDENSING BOILER


28

FIGURE 40: MONTHLY DATA FOR TOTAL ELECTRICITY USAGE – GAS

CONDENSING BOILER

FIGURE 41: MONTHLY DATA FOR TOTAL FUEL USAGE – GAS

CONDENSING BOILER

Figure 39 and Table show the energy usage associated with the gas condensing boiler and like the

base run it can be seen that space heating uses the majority of the energy. It can also be seen that

with gas condensing boiler being used there is a significant decrease in the amount of energy being

used when compared to the base run.

Electricity Usage

Like The base run it can be seen in Figure 40 and Table 8 that it is mainly lights and electrical

equipment that uses the most electricity. It can also be seen that using the gas condensing boiler

uses around half the electricity that air source heat pump uses.

Fuel Usage



April 29605 KW/h

May 29081 KW/h


TABLE 8: MONTHLY USAGE FOR

ELECTRICITY –GAS CONDENSING BOILER



April 347871 kBtu

May 241342 kBtu


TABLE 9: MONTHLY USAGE FOR FUEL – GAS

CONDENSING BOILER

KWh

KBtu


29

Figure 41 and Table 9 show the fuel usage within the building and it is seen that the majority of the

fuel is being used for space heating, much like the base run. The higher efficiency of the boiler being

used means that less fuel is being used over all when compared to the bas run results shown in

Figure 27 and Table 3.

Costs

The cost of the energy, electricity and fuel usage can be seen in Appendix E.

3.2.3.4 Comparisons

FIGURE 42: TOTAL ENERGY USED (KWH/M2/ANNUM) FOR EACH RUN COMPARED TO NZEB TARGETS

Figure 42 shows a chart that compares the energy usage of the 3 simulation and also compares them

against the NZEB targets. Column A shows the minimum NZEB target for a new educational building,

which can been seen in section 3.1.2, while column B shows the minimum NZEB targets set out for

an existing building also seen in section 3.1.2. It is clearly seen that none of the simulations achieve

any of these targets. However the accuracy of these results is called into question when there is a

limited supply of HVAC systems to choose from and also there are limited data input options. With

further research into building simulation software it was difficult to analyse the predicted and

realistic energy use of a building. The research conducted by Reeves, Olbina and Issa, which looks at

validation of building energy modelling tools claims that the building energy simulation software

couldn’t accurately predict the energy use within a building (Reeves, Olbina et al. 2012) and this can

be seen throughout the research conducted in this report with the results being based on

assumptions due to software limitation.

0

100

200

300

400

500

600

ENERGY USAGE

NZEB TARGET: NEW

BUILDING, 60

NZEB TARGET:

EXISTING

BUILDINGS, 160

BASE RUN, 560 AIR SOURCE HEAT

PUMP, 219 GAS CONDENSING

BOILER, 442

kW

h/m

2 /

an

nu

m

Total Energy Usage kWh/m2/annum

D A

NNBAG

01000

kT

B

NNBAG

01000

kT

C

NNBAG

01000

kT

E

NNBAG

01000

kT


30

SECTION 4.0 Results

This research conducted into this area gave unexpected results. It was to be expected at the start of

this report that using BIM and building performance simulation software would be a quick and

accurate way to help a designer analyse the energy usage within a building. It was also expected to

show how this type of software and new innovations in building design can help buildings reach the

targets set out in the Technical Guidance Documents Part L 2011 and NZEB targets that are set for

2018, but none of the simulations meet the minimum targets set out. It is clearly seen that in Figure

42 that an Air Source Heat Pump uses less energy of the 3 simulations. While a gas condensing boiler

uses less energy when compared to the standard boiler used in the base run, but as stated above

none reach the desired targets.

The accuracy of these results can be questioned since Green Building Studio uses assumptions when

looking photovoltaic potential, occupancy of the building, HVAC systems etc. The software doesn’t

allow for more precise data to be inputted, giving a more accurate representation of energy use

within the building. Knight, Stravoravdis & Lasvaux states that the results from an analysis using

building energy performance software can prove to be inaccurate mainly due to the data input and

in the future there needs to be a greater accuracy in the data used by the software and allow for

more accurate input to the simulation. (Knight, Stravoravdis et al. 2007)

SECTION 5.0 Conclusions and Recommendations

5.1 Conclusion

There are a number of software options available all with different levels of difficulty to use. From

the research acquired from the secondary research, IES VE software would have produced more

accurate results but that software has a very steep learning curve and require training to use to

produce accurate results. Another major issue was the compatibility with the Revit model with many

unknown problems arising when importing the model. However even IES VE wouldn’t of produced

an accurate representation of the energy use in the building. (Reeves, Olbina et al. 2012)


31

Autodesk Green Building Studio was the alternative option but again there was a learning curve

involved with it. The software had many limitations mainly being the limited HVAC systems that can

be used and the use of assumptions when it came to the PV potential and building occupancy.

These limitations didn’t allow for an accurate representation of the energy use within the building

and the results didn’t reach the desired NZEB targets. Further research into this area showed that it

is very difficult to accurately predict the energy use of a building using simulation software and that

more accurate data will be required from the software to produce more accurate results. (Knight,

Stravoravdis et al. 2007)

In conclusion the area of building energy performance simulation is a specialised area and should be

done by someone who specialises in this field. There is a need for training in the software along with

a good knowledge of HVAC systems, renewable technologies and building technologies. For a

designer not trained in this area the results should be used as a guide and help with design decisions

at an early stage and help achieve the NZEB target for the building.

5.2 Recommendations

More research into this area is recommended and the results should be compared to hand

calculations to test the accuracy of the results. Before deciding on which software option to use the

user needs to have an understanding and training using the software and an understanding of

building services along with renewable technologies and building technologies.


32

APPENDICES

Appendix A: Plagiarism Declaration

Galway Mayo Institute of Technology

B.Sc. (Honours) in Architectural Technology

PLAGIARISM- DECLARATION COVER SHEET

PLAGIARISM

Plagiarism consists of a person presenting another person’s ideas, findings or work as one’s own by copying or

reproducing the work without due acknowledgement of the source. Plagiarism is the theft of intellectual

property. The Institute regards plagiarism as a very serious offence. At the very least, it is a misuse of

academic conventions or the result of poor referencing practice. Where it is deliberate and systematic,

plagiarism is cheating.

Plagiarism can take several forms, examples of which are given below:

a. Presenting substantial extracts from books, journal articles, these and other published or unpublished work

(e.g. working papers, seminars and conference papers, internal reports, computer software, lecture notes

or tapes, and other students’ work) without clearly indicating the source of the material;

b. Using very close paraphrasing of sentences or whole paragraphs without due acknowledgement in the

form of reference to the original work;

c. Quoting directly from a source and failing to insert quotation marks around the quoted passages. In such

cases it is not adequate merely to acknowledge the source;

d. Copying essays or essay extracts or buying existing essays from Internet websites or other sources;

e. Closely replicating the structure of someone else’s argument without clear reference to the source.

The Institute is committed to detecting all cases of student plagiarism. All cases will be dealt with in

accordance with the Institute’s Examination Regulations:

Penalties for plagiarism include:

a. Awarding lower marks or no marks for the Technical Report;

c. Awarding a lower class of degree or other academic award;

d. Excluding the student from the award of a degree or other academic award, which may be either

permanent or for a stated period.

PLAGIARISM DECLARATION

By signing this declaration, you are confirming in writing that the work you are submitting is original and

does not contain any plagiarised material.

I confirm that this Technical Report is my own work, and that the work of other persons has been fully

acknowledged.

Your signature: . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. . . . . Date: ………………………..

Name: Mark Thornton

Technical Report Title: The use of BIM to analyse the building energy performance of a retrofitted

educational building in Ireland (Building and Civil Engineering Department – GMIT)


33

Appendix B: Weather Data – Wind Roses

Figure 43 and figure 44 show the wind roses from the weather and location analysis done by green building

studio. It shows the wind speed and wind direction which would help the designer to incorporate a wind

turbine if desired.

FIGURE 43: WINTER AND SUMMER WIND ROSES

FIGURE 44: ANNUAL WIND ROSE CHART

SHOWING WIND DIRECTION ALONG WITH

THE WIND SPEED


34

Appendix C: Base Run Costs

Base run Total energy costs

Base run Total electricity costs

Month Total Energy Costs

€

Energy Costs per M2

€

January € 15,109 € 5

February € 13,812 € 4

March € 14,573 € 4

April € 11,302 € 3

May € 9,530 € 3

June € 7,339 € 2

July € 7,339 € 2

August € 7,369 € 2

September € 6,981 € 2

October € 9,373 € 3

November € 12,442 € 4

December € 13,874 € 4

TABLE 10: TOTAL MONTHLY AND COST PER M2 ENERGY COSTS

TABLE 11: TOTAL MONTHLY AND COST PER M2 ELECTRICITY COSTS

Month Total Electricity

Costs €

Electricity Costs per M2

€

January € 6,609 € 2

February € 6,044 € 2

March € 6,640 € 2

April € 5,684 € 2

May € 5,515 € 2

June € 5,424 € 2

July € 5,938 € 2

August € 5,405 € 2


October € 5,383 € 2

November € 5,818 € 2

December € 6,234 € 2

COST €

COST €

FIGURE 45: TOTAL ENERGY COSTS - BASE RUN

FIGURE 46: TOTAL ELECTRICITY COSTS - BASE RUN


35

Base run Total fuel costs

Appendix D: Air Source Heat Pump Costs

Air Source Heat Pump Total energy costs

Month Total Fuel Costs

€

Fuel Costs per M2

€

January € 8,500 € 3


March € 7,933 € 2

April € 5,618 € 2

May € 4,015 € 1

June € 1,915 € 0.58

July € 1,239 € 0.38

August € 1,964 € 0.60

September € 2,091 € 0.64

October € 3,991 € 1



TABLE 12: TOTAL MONTHLY AND COST PER M2

FUEL COSTS


€

Energy Costs per M2

€

January € 12,934 € 4

February € 11,582 € 4

March € 12,647 € 4

April € 8,464 € 3

May € 7,381 € 2

June € 6,512 € 2

July € 6,430 € 2

August € 6,545 € 2


October € 6,444 € 2


December € 10,600 € 3

TABLE 13: TOTAL MONTHLY AND COST PER M2 ENERGY COSTS -

AIR SOURCE HEAT PUMP

COST €

COST €

COST €

FIGURE 47: TOTAL FUEL COSTS - BASE RUN

FIGURE 48: TOTAL ENERGY COSTS - AIR SOURCE HEAT PUMP


36

Air Source Heat Pump Total Electricity Costs

Air Source Heat Pump Total Fuel Costs


Costs €


€

January € 12,466 € 4

February € 11,145 € 3

March € 11,957 € 4

April € 7,998 € 2

May € 6,917 € 2

June € 6,072 € 2

July € 6,018 € 2

August € 6,114 € 2


October € 7,015 € 2


December € 10,148 € 3


ELECTRICITY COSTS

- AIR SOURCE HEAT PUMP


€

Fuel Costs per M2

€

January € 468 € 0.14

February € 437 € 0.13

March € 507 € 0.15

April € 466 € 0.14

May € 464 € 0.14

June € 440 € 0.13

July € 412 € 0.13

August € 432 € 0.13

September € 391 € 0.12

October € 430 € 0.13

November € 419 € 0.13

December € 452 € 0.14

TABLE 15: TOTAL MONTHLY AND COST PER M2 FUEL COSTS - AIR

SOURCE HEAT PUMP

COST €

COST €

FIGURE 49: TOTAL ELECTRICITY COSTS - AIR SOURCE HEAT PUMP

FIGURE 50: TOTAL FUEL COSTS - AIR SOURCE HEAT PUMP


37

Appendix E: Gas Condensing Boiler Costs

Gas Condensing Boiler Total energy costs

Gas Condensing Boiler Total electricity costs


€

Energy Costs per M2

€

January € 12,565 € 4

February € 11,486 € 4

March € 12,016 € 4

April € 9,241 € 3

May € 7,855 € 2

June € 6,025 € 2

July € 5,749 € 2

August € 6,197 € 2

September € 5.848 € 2

October € 7,780 € 2

November € 10,243 € 3

December € 11,571 € 4

TABLE 16: TOTAL MONTHLY AND COST PER M2 ENERGY COSTS -

GAS CONDENSING BOILER


Costs €


€

January € 5,779 € 2


March € 5,779 € 2

April € 5,003 € 2

May € 4,915 € 2

June € 4,767 € 1

July € 4,991 € 2

August € 4,906 € 2


October € 4,872 € 2




ELECTRICITY COSTS - GAS CONDENSING BOILER

COST €

COST €

FIGURE 51: TOTAL ENERGY COSTS - GAS CONDENSING BOILER

FIGURE 52: TOTAL ELECTRICITY COSTS - GAS CONDENSING

BOILER


38

Gas Condensing Boiler Total fuel costs

Appendix F: Cost Comparison

FIGURE 54: TOTAL ENERGY COST PER YEAR FOR EACH DESIGN OPTION

Figure 54 shows the total annual cost for each run. The air source heat pump costs less to run per

year but there isn’t much difference between that and the gas condensing boiler. If a boiler was to

be used a high efficiency gas condensing boiler should be used based on these results. Again the

accuracy of these results are called into question due to the default values used but if one had the

current values for electricity and fuel the results could be more accurate.

0

20,000

40,000

60,000

80,000

100,000

120,000

140,000

Total Cost

BASE RUN,

128,875

AIR SOURCE

HEAT PUMP ,

105369

GAS

CONDENSING

BOILER, 106585

Eu

ro €

Total Energy Cost Per Year


€

Fuel Costs per M2

€

January € 6,785 € 2


March € 6,237 € 2

April € 4,238 € 1

May € 2,940 € 0.90

June € 1,258 € 0.38

July € 759 € 0.23

August € 1,291 € 0.40

September € 1,415 € 0.44

October € 2,908 € 0.89



TABLE 18: TOTAL MONTHLY AND COST PER M2 FUEL COSTS - GAS

CONDENSING BOILER

COST €

FIGURE 53: TOTAL FUEL COSTS - GAS CONDENSING BOILER


39

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