Transcript Low Energy Buildings - heating/cooling of

Low Energy Cooling
BRE, 17th April 2007
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)
CRed
Carbon Reduction
Energy Science Director CRed
HSBC Director of Low Carbon Innovation
Acknowledgement: Charlotte Turner
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Original buildings
Teaching wall
Library
Student
residences
2
Nelson Court
Constable Terrace
3
Low Energy Educational Buildings
Nursing and
Midwifery
School
Medical School Phase 2
ZICER
Elizabeth Fry
Building
Medical School
4
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. 5
ZICER Building
Low Energy Building of the Year Award 2005 awarded
by the Carbon Trust.
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
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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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ZICER Building
Photo shows
only part of top
Floor
•
•
•
•
Top floor is an exhibition area – also to promote PV
Windows are semi transparent
Mono-crystalline PV on roof ~ 27 kW in 10 arrays
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Poly- crystalline on façade ~ 6/7 kW in 3 arrays
Operation of the Main Building
• Mechanically ventilated that utilizes hollow core ceiling
slabs as supply
air ducts to the space
Regenerative
heat
Space for future
exchanger
chilling
Incoming
Filter Heater
air into
the AHU
The air passes
through hollow
cores in the
ceiling slabs
The
Out
of return
the air passes
through the heat
building
Return stale air is
Air enters the internal
exchanger
extracted from each floor occupied space
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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
night ventilation/
free cooling
Draws out the heat
accumulated during
Cools the slabs to
the day
act as a cool store
the following day
Summer
night
Cold air
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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
The concrete
Pre-cools
thestores
air
absorbs and
before
entering
thea
the heat
– like
occupiedinspace
radiator
reverse
Warm
air
Summer
day
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Effect of New Control Strategies on Thermal Comfort
50
50
Year 2
Year 1
30
20
Year 2
30
20
10
10
0
0
-3
-2
-1
Year 1
40
Percentage
Percentage
40
0
1
2
3
-3
-2
-1
Actual Vote
Winter
0
Actual Vote
1
2
3
Summer
Number
Mean Vote
Number
Mean Vote
2004
224
0.10
352
0.12
2005
256
0.12
273
0.44
Only data for relevant Metabolic Rates included in above table
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Life Cycle Energy Requirements of ZICER as built compared to
other heating/cooling strategies
54%
Naturally
Ventilated
221508GJ
28%
51%
Air Conditioned
384967GJ
34%
As Built
209441GJ
Materials Production
Materials Transport
On site construction energy
Workforce Transport
Intrinsic Heating / Cooling energy
Functional Energy
Refurbishment Energy
Demolition Energy
29%
61%
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Life Cycle Energy Requirements of ZICER compared to other buildings
300000
ZICER
250000
Naturally Ventilated
GJ
200000
Air Conditrioned
150000
100000
50000
0
0
5
10 15 20 25 30 35 40 45 50 55 60
80000
Years
GJ
60000
Compared to the Air-conditioned
office, ZICER as built recovers
extra energy required in
construction in under 1 year.
40000
20000
ZICER
Naturally Ventilated
Air Conditrioned
0
0
1
2
3
4
5
6
7
8
9
10
Years
15
Conversion efficiency improvements – Building Scale CHP
3% Radiation Losses
11%
61% Flue
Flue Losses
Losses
Exhaust
Heat
Exchanger
36%
86%
GAS
efficient
Localised generation
makes use of waste heat.
Reduces conversion
losses significantly
Engine
Engine heat Exchanger
Generator
36%
Electricity
50% Heat
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Conversion efficiency improvements
Before installation
1997/98
MWh
electricity
gas
oil
19895
35148
33
Total
Emission factor
kg/kWh
0.46
0.186
0.277
Carbon dioxide
Tonnes
9152
6538
9
Electricity
After installation
1999/
Total
CHP export
2000
site generation
MWh 20437 15630
977
Emission kg/kWh
-0.46
factor
CO2
Tonnes
-449
15699
Heat
import boilers CHP
oil
total
5783
14510 28263 923
0.46
0.186
0.186 0.277
2660
2699
5257 256 10422
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 effectively
More electricity could be generated in summer
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Conversion efficiency improvements
Normal Chilling
Adsorption
Chilling
Heat from external
source
Heat rejected
High Temperature
High Pressure
Desorber
Heat
Compressor
Exchanger
Condenser
Throttle
Valve
W~0
Evaporator
Absorber
Heat extracted
for cooling
Low Temperature
Low Pressure
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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.
"If you do not change direction, you may end up where
you are heading."
Lao Tzu (604-531 BC) Chinese Artist and Taoist philosopher
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