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Carbon Reduction Strategies at the University of East Anglia

Elizabeth Fry BuildingZICER

CHP Generation at UEA

CRedCarbon Reduction

10th May 2008

N.K. Tovey (杜伟贤 ) M.A, PhD, CEng, MICE, CEnv

Н.К.Тови М.А., д-р технических наук

Energy Science Director CRed Project

HSBC Director of Low Carbon Innovation

Recipient of James Watt Gold Medal2007

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Original buildings

Teaching wall

Library

Student residences

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Nelson Court

Constable Terrace

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Low Energy Educational BuildingsDüşük Enerjili Eğitim Binaları

Elizabeth Fry Building

Elizabeth Fry Binası

ZICER

Nursing and Midwifery

Hemşirelik ve Ebelik Okulu

Medical SchoolTıp Fakültesi Binası

Medical School Phase 2 Tıp Fakültesi Binası 2. Evre

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The Elizabeth Fry Building 1994Elizabeth Fry Binası - 1994

Cost ~6% more but has heating requirement ~20% of average building at time.Significantly outperforms even latest Building Regulations.Runs on a single domestic sized central heating boiler.

Maliyeti ~%6 daha fazla olsada, ısınma ihtiyacı zamanın ortalama binalarının ~%20’si.En son Bina Yönetmeliklerini bile büyük ölçüde aşmaktadır.

Tek bir ev tipi merkezi ısıtma kazanı ile çalışmaktadır.

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Conservation: management improvements –

Careful Monitoring and Analysis can reduce energy consumption.

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50

100

150

200

250

Elizabeth Fry Low Average

kWh/

m2/

yr

gas

electricity

thermal comfort +28%User Satisfaction

noise +26%

lighting +25%

air quality +36%

A Low Energy Building is also a better place to work in

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ZICER Building

Heating Energy consumption as new in 2003 was reduced by further 50% by careful record keeping, management techniques and an adaptive approach to control.

Incorporates 34 kW of Solar Panels on top floor

Low Energy Building of the Year Award 2005 awarded by the Carbon Trust.

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The ZICER Building - Description

• Four storeys high and a basement• Total floor area of 2860 sq.m• Two construction types

Main part of the building

• High in thermal mass • Air tight• High insulation standards • Triple glazing with low emissivity

Structural Engineers: Whitby Bird

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The ground floor open plan office

The first floor open plan office

The first floor cellular offices

11Air enters the internal

occupied space

Return stale air is extracted from each floor

Incoming air into

the AHU

Regenerative heat exchanger

Filter Heater

The air passes through hollow

cores in the ceiling slabs

The return air passes through the heat

exchanger

Out of the building

Operation of the Main Building• Mechanically ventilated that utilizes hollow core ceiling slabs as supply air ducts to the space

Space for future chilling

Recovers 87% of Ventilation Heat Requirement.

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Importance of the Hollow Core Ceiling Slabs

The concrete hollow core ceiling slabs are used to store heat and coolness at different times of the year to provide comfortable and stable temperatures

Cold air

Cold air

Draws out the heat accumulated during

the dayCools the slabs to act as a cool store the following day

Summer night

night ventilation/ free cooling

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Importance of the Hollow Core Ceiling Slabs

The concrete hollow core ceiling slabs are used to store heat and coolness at different times of the year to provide comfortable and stable temperatures

Warm air

Warm air

Pre-cools the air before entering the

occupied space

The concrete absorbs and stores

the heat – like a radiator in reverse

Summer day

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Importance of the Hollow Core Ceiling Slabs

The concrete hollow core ceiling slabs are used to store heat and coolness at different times of the year to provide comfortable and stable temperatures

Winter Day

The concrete slabs absorbs and

store heat

Heat is transferred to the air before entering

the room

Winter day

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Importance of the Hollow Core Ceiling Slabs

The concrete hollow core ceiling slabs are used to store heat and coolness at different times of the year to provide comfortable and stable temperatures

Winter NightWhen the internal air temperature drops, heat stored in the

concrete is emitted back into the room

Winter night

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The Energy Signature from the Old and the New Heating Strategies

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200

400

600

800

1000

-4 -2 0 2 4 6 8 10 12 14 16 18

Mean external temperature over a 24 hour period (degrees C)

Hea

tin

g a

nd

ho

t-w

ate

r

con

sum

pti

on

(k

Wh

/24

ho

ur

per

iod

)

New Heating Strategy Original Heating Strategy

350

The space heating consumption has reduced by 57%

Good Management has reduced Energy Requirements

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• Top floor is an exhibition area – also to promote PV

• Windows are semi transparent

• Mono-crystalline PV on roof ~ 27 kW in 10 arrays

• Poly- crystalline on façade ~ 6/7 kW in 3 arrays

ZICER Building

Photo shows only part of top

Floor

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1000

2000

3000

4000

5000

6000

7000

(Jan ) 1 (Mar) 11 (May) 21 (Aug) 31 (Oct) 41 (Dec) 51

Time (week number)

Ele

ctri

city

use

d/ge

nera

ted

(kW

h)

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10

20

30

40

50

60

70

PV

per

cent

age

of th

e to

tal e

lect

rici

ty u

sage

Electricity from conventional sources PV electricity PV % of total

Performance of PV cells on ZICER

02040

6080

100120140

160180200

9 10 11 12 13 14 15Time of Day

Wh

01020

3040506070

8090100

%

Top Row

Middle Row

Bottom Row

radiation

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20

30

40

50

60

70

80

90

100

9 10 11 12 13 14 15Time of day

Wh

0

10

20

30

40

50

60

70

80

90

100

%

Block1

Block 2

Block 3

Block 4

Block 5

Block 6

Block 7

Block 8

Block 9

Block 10

radiation

All arrays of cells on roof have similar performance respond to actual solar radiation

The three arrays on the façade respond differently

Performance of PV cells on ZICER

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5

10

15

20

25

8.00 9.00 10.00 11.00 12.00 13.00 14.00 15.00 16.00

Time (hours)

Elev

ation

in th

e sky

(deg

rees)

January February November DecemberP1 - bottom PV row P2 - middle PV row P3 - top PV row

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Arrangement of Cells on Facade

Individual cells are connected horizontally

As shadow covers one column all cells are inactive

If individual cells are connected vertically, only those cells actually in shadow are affected.

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Use of PV generated energy

Sometimes electricity is exportedInverters are only 91% efficient

Most use is for computers

DC power packs are inefficient typically less than 60% efficientNeed an integrated approach

Peak output is 34 kW

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Actual Situation excluding Grant

Actual Situation with Grant

Discount rate 3% 5% 7% 3% 5% 7%

Unit energy cost per kWh (£) 1.29 1.58 1.88 0.84 1.02 1.22

Avoided cost exc. the Grant

Avoided Costs with Grant

Discount rate 3% 5% 7% 3% 5% 7%

Unit energy cost per kWh (£) 0.57 0.70 0.83 0.12 0.14 0.16

Grant was ~ £172 000 out of a total of ~ £480 000

Performance of PV cells on ZICER

Cost of Generated Electricity

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EngineGenerator

36% Electricity

50% Heat

GAS

Engine heat Exchanger

Exhaust Heat

Exchanger

11% Flue Losses3% Radiation Losses

86%

efficient

Localised generation makes use of waste heat.

Reduces conversion losses significantly

Conversion efficiency improvements – Building Scale CHP

61% Flue Losses

36%

efficient

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Conversion efficiency improvements

1997/98 electricity gas oil Total

MWh 19895 35148 33

Emission factor kg/kWh 0.46 0.186 0.277

Carbon dioxide Tonnes 9152 6538 9 15699

Electricity Heat

1999/2000

Total site

CHP generation

export import boilers CHP oil total

MWh 20437 15630 977 5783 14510 28263 923Emission

factorkg/kWh -0.46 0.46 0.186 0.186 0.277

CO2 Tonnes -449 2660 2699 5257 256 10422

Before installation

After installation

This represents a 33% saving in carbon dioxide

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Conversion efficiency improvements

Load Factor of CHP Plant at UEA

Demand for Heat is low in summer: plant cannot be used effectivelyMore electricity could be generated in summer

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Conversion efficiency improvements

Condenser

Evaporator

Throttle Valve

Heat rejected

Heat extracted for cooling

High TemperatureHigh Pressure

Low TemperatureLow Pressure

Heat from external source

Absorber

Desorber

Heat Exchanger

W ~ 0

Normal Chilling

Compressor

Adsorption Chilling

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A 1 MW Adsorption chiller

1 MW 吸附冷却器

• Reduces electricity demand in summer

• Increases electricity generated locally

• Saves ~500 tonnes Carbon Dioxide annually

• Uses Waste Heat from CHP

• provides most of chilling requirements in summer

•从 CHP 中使用废热•在夏天提供绝大部分供冷需要

•减少夏天电耗•增加本地发电量•每年节约 ~500 吨二氧化碳

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Target Day

Results of the “Big Switch-Off”

With a concerted effort savings of 25% or more are possibleHow can these be translated into long term savings?

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Conclusions• Buildings built to low energy standards have cost ~ 5% more,

but savings have recouped extra costs in around 5 years.

• Ventilation heat requirements can be large and efficient heat recovery is important.

• Effective adaptive energy management can reduce heating energy requirements in a low energy building by 50% or more.

• Photovoltaic cells need to take account of intended use of electricity use in building to get the optimum value.

• Building scale CHP can reduce carbon emissions significantly

• Adsorption chilling should be included to ensure optimum utilisation of CHP plant, to reduce electricity demand, and allow increased generation of electricity locally.

• Promoting Awareness can result in up to 25% savings

• The Future for UEA: Biomass CHP? Wind Turbines?

Lao Tzu (604-531 BC) Chinese Artist and Taoist philosopher

"If you do not change direction, you may end up where you are heading."

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WEBSITE cred-uk.org/

This presentation is available from tomorrow at above WEB Site: follow Academic Links

Keith Tovey (杜伟贤 ) Energy Science Director

HSBC Director of Low Carbon Innovation

Carbon Reduction Strategies at the University of East Anglia