Transcript Carbon Reduction Strategies at the University of East Anglia

Institution of Civil Engineers
30th January 2006
Carbon Reduction Strategies at the
University of East Anglia
•
Low Energy Buildings
• Providing Low Carbon Energy on Campus
Keith Tovey (杜伟贤)
MA, PhD, CEng, MICE, CEnv
CRed
Carbon Reduction
Energy Science Director CRed
HSBC Director of Low Carbon Innovation
Charlotte Turner
1
Original buildings
Teaching wall
Library
Student
residences
2
Nelson Court
Constable Terrace
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Low Energy Educational Buildings
Medical
School
ZICER
Nursing and
Midwifery
School
Elizabeth
Fry Building
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.
Would have scored 13 out of 10 on the Carbon Index Scale.
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8
Conservation: management improvements –
250
gas
200
kWh/m2/yr
electricity
150
100
50
0
Elizabeth Fry
Low
Average
User Satisfaction
thermal comfort +28%
air quality
+36%
lighting
+25%
noise
+26%
A Low Energy Building is
also a better place to work in
Careful Monitoring and Analysis can reduce energy
consumption.
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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 50%
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
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
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Operation of the Main Building
• Mechanically ventilated using hollow core ceiling slabs
as supply air heat
ducts to the space
Regenerative
Recovers 87% of
exchanger
Ventilation Heat
Incoming
FilterHeater
Requirement.
air into
the AHU
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
Summer
Night
night
Draws out
the –heat
ventilation/free
cooling
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
Summerthe
Day
Pre-cools
air
before entering the
The concrete
occupied
space
absorbs and stores
the heat – like a
radiator in reverse
Warm
air
Summer
day
12
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
TheHeat
concrete
is
slabs
transferred
absorbs
to the
and
air before
store heat
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
Night air
When
the internal
temperature drops,
heat stored in the
concrete is emitted
back into the room
Winter
night
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Good Management has reduced Energy Requirements
The Energy Signature from the Old and the New Heating
Strategies
Heating and hot-water
consumption (kWh/24 hour
period)
1000
800
The space heating
consumption has
reduced by 57%
600
400
350
200
0
-4
-2
0
2
4
6
8
10
12
14
16
18
Mean external temperature over a 24 hour period (degrees C)
New Heating Strategy
Original Heating Strategy
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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
Performance of PV cells on ZICER
70
7000
PV electricity
PV % of total
6000
60
5000
50
4000
40
3000
30
2000
20
1000
10
0
(Jan ) 1
PV percentage of the total electricity usage
Electricity used/generated (kWh)
Electricity from conventional sources
0
(Mar) 11
(May) 21
(Aug) 31
Time (week number)
(Oct) 41
(Dec) 51
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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
Peak output is 34 kW
Sometimes electricity is exported
Inverters are only 91% efficient
Most use is for computers
DC power packs are inefficient
typically less than 60% efficient
Need an integrated approach
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Performance of PV cells on ZICER
Cost of Generated Electricity
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
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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
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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
• 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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Results of the “Big Switch-Off”
Target Day
With a concerted effort savings of 25% or more are possible
How 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?
"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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Carbon Reduction Strategies at
the University of East Anglia
WEBSITE cred-uk.org/
This presentation will be available from
tomorrow at above WEB Site:
follow Academic Links
Keith Tovey (杜伟贤)
Energy Science Director
HSBC Director of Low Carbon Innovation
Charlotte Turner
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