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CRedCarbon Reduction

Energy Science Director: HSBC Director of Low Carbon Innovation

School of Environmental Sciences, University of East Anglia

A Stern Warning

24th May 2007

Keith Tovey (杜伟贤 ) M.A., PhD, CEng, MICE, CEnvCRed

The Zicer building, its construction and performance and other Low Carbon Strategies at UEA.

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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 Buildings

Elizabeth Fry Building

ZICER

Nursing and Midwifery

School

Medical School

Medical School Phase 2

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The Elizabeth Fry Building 1994

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Cost ~6% more but has heating requirement ~25% of average building at time.

Building Regulations have been updated: 1994, 2002, 2006, but building outperforms all of these.

Runs on a single domestic sized central heating boiler.

Would have scored 13 out of 10 on the Carbon Index Scale.

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Conservation: management improvements –

Careful Monitoring and Analysis can reduce energy consumption.

0

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 57% 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

~ U – value ~ 1.0 W m2 K-1

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The ground floor open plan office

The first floor open plan office

The first floor cellular offices

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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

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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Performance of ZICER Building

• Initially performance was poor• Performance improved with new Management Strategy

20052004

EFry

ZICER

New Management

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The Energy Signature from the Old and the New Heating Strategies

0

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 an

d h

ot-w

ater

co

nsu

mp

tion

(k

Wh

/day

)

New Heating Strategy Original Heating Strategy

The space heating consumption has reduced by 57%

800

350

Acknowledgement: Charlotte Turner

Good Management has reduced Energy Requirements

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Effect of New Control Strategies on Thermal Comfort

Number Mean Vote Number Mean Vote

2004 224 0.10 352 0.12

2005 256 0.12 273 0.44

Winter Summer

Only data for relevant Metabolic Rates included in above table

0

10

20

30

40

50

-3 -2 -1 0 1 2 3

Actual Vote

Per

cen

tage

Year 2

Year 1

Winter

0

10

20

30

40

50

-3 -2 -1 0 1 2 3

Actual Vote

Per

cent

age

Year 1

Year 2

Summer

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0

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)

0

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

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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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Energy Conversion efficiency improvements

Load Factor of CHP Plant at UEA

Demand for Heat is low in summer: plant cannot be used effectively

More electricity could be generated in summer

-500

0

500

1000

1500

2000

2500

3000CHP

Import

Export

1999 - 00 2000 - 01 2001 - 02 2002 - 03 2003 - 04 2004 - 05

Performance of UEA CHP plant

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Compressor

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 ChillingAdsorption Chilling

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A 1 MW Adsorption chiller

1 MW 吸附冷却器

• Adsorption Heat pump uses Waste Heat from CHP

• Will provide most of chilling requirements in summer

• Will reduce electricity demand in summer

• Will increase electricity generated locally

• Save 500 – 700 tonnes Carbon Dioxide annually

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As Built 209441GJ

Air Conditioned 384967GJ

Naturally Ventilated 221508GJ

Life Cycle Energy Requirements of ZICER as built compared to other buildings of same size and design

Materials Production

Materials Transport

On site construction energy

Workforce Transport

Intrinsic Heating / Cooling energy

Functional Energy

Refurbishment Energy

Demolition Energy

28%54%

34%51%

61%

29%

Main TermoDeck Building only

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0

50000

100000

150000

200000

250000

300000

0 5 10 15 20 25 30 35 40 45 50 55 60

Years

GJ

ZICER

Naturally Ventilated

Air Conditrioned

Life Cycle Energy Requirements of ZICER compared to other buildings

Compared to the Air-conditioned office, ZICER as built recovers extra energy required in construction in under 1 year.

0

20000

40000

60000

80000

0 1 2 3 4 5 6 7 8 9 10

Years

GJ

ZICER

Naturally Ventilated

Air Conditrioned

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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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A Stern Warning 24th May 2007

The Zicer building, its construction and performance and other Low Carbon Strategies at UEA.

Keith Tovey (杜伟贤 ) Energy Science Director HSBC Director of Low Carbon Innovation

Acknowledgement: Charlotte TurnerCRed

Carbon Reduction

CRed

This presentation is now accessible on the WEB at:

www2.env.uea.ac.uk/cred/creduea.htm

see also www.cred-uk.org