low energy cooling bre, 17th april 2007
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C Red. Carbon Reduction. Low Energy Cooling BRE, 17th April 2007. Case Study: Termodeck Buildings at the University of East Anglia and Low Carbon Strategies at UEA. - PowerPoint PPT PresentationTRANSCRIPT
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Low Energy Cooling BRE, 17th April 2007
• Low Energy Buildings - heating/cooling of Termodeck Buildings at UEA.
• Life Cycle Issues
• Providing Low Carbon Energy and cooling on the UEA Campus
Case Study: Termodeck Buildings at the University of East Anglia and Low Carbon Strategies at UEA
• Low Energy Buildings - heating/cooling of Termodeck Buildings at UEA.
• Life Cycle Issues
• Providing Low Carbon Energy and cooling on the UEA Campus
Keith Tovey (杜伟贤 ) Energy Science Director HSBC Director of Low Carbon Innovation
Acknowledgement: Charlotte TurnerCRed
Carbon Reduction
CRed
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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
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.
Careful Monitoring, Analysis and Adaptive control can reduce energy consumption.
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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
10Air 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
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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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Effect of New Control Strategies on Thermal Comfort
0
10
20
30
40
50
-3 -2 -1 0 1 2 3
Actual Vote
Per
cen
tage
Year 2
Year 1
0
10
20
30
40
50
-3 -2 -1 0 1 2 3
Actual Vote
Per
cent
age
Year 1
Year 2
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
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As Built 209441GJ
Air Conditioned 384967GJ
Naturally Ventilated 221508GJ
Life Cycle Energy Requirements of ZICER as built compared to other heating/cooling strategies
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%
15
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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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
• 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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The Future
• New Medical School – 5th Termodeck Building on Campus– Will have full backup central computing server in
basement.– Cooling for this area will reject heat into heater banks
for heating building during winter. – May not need any other heating for building.– Initially chilling provided locally – ultimately connected
to UEA chilling network
• Top Floor of ZICER – Seminar Room– Investigate provision of Heating / Cooling of room
linked to room booking – i.e. only provide heating cooling to a high thermal acceptance level if room is booked in advance.
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Conclusions• The Termodeck construction is an effective method to
provide heating and cooling.
• Pre-cooling building overnight is an effective method to avoid /reduce the need for air-conditioning
• Close integration between client and designers regarding functional use of building is required to ensure effective provision of cooling.
• 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.
Lao Tzu (604-531 BC) Chinese Artist and Taoist philosopher
"If you do not change direction, you may end up where you are heading."