Transcript Developing and Evolving a Low Carbon Campus

CRed
Carbon Reduction
The Design and Management of
Sustainable Learning Environments
18th June 2008
Developing and Evolving a Low Carbon Campus
Experience of the University of East Anglia
Recipient of James Watt Medal
5th October 2007
N.K. Tovey (杜伟贤) M.A, PhD, CEng, MICE, CEnv
CRed наук
Н.К.Тови М.А., д-р технических
Energy Science Director CRed Project
HSBC Director of Low Carbon Innovation
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Original buildings
Teaching wall
Library
Student
residences
2
Nelson Court
Constable Terrace
3
Constable Terrace - 1993
• Four Storey Student Residence
• Divided into “houses” of 10
units each with en-suite facilities
• Heat Recovery of body and cooking
heat ~ 50%.
• Insulation standards exceed 2006
standards
• Small 250 W panel heaters in
individual rooms.
Electricity Use
Carbon Dioxide Emissions - Constable Terrace
12%
21%
140
Appliances
120
Lighting
100
MHVR Fans
MHVR Heating
18%
Panel Heaters
Hot Water
18%
Kg/m2/yr
14%
80
60
40
20
0
17%
UEA
Low
Medium
4
Low Energy Educational Buildings
Medical School Phase 2
ZICER
Elizabeth Fry
Building
Nursing and
Midwifery
School
Medical School
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.
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250
gas
200
kWh/m2/yr
150
100
50
0
Elizabeth Fry
140
Heating/Cooling
Hot Water
Electricity
120
2
electricity
Energy Consumption kWh/m /annum
Conservation: management improvements –
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
100
80
60
40
20
0
1995 1996 1997 1998 1999 2000 2001 2002 2003 2004
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
8
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 Main Building
Mechanically ventilated using hollow core slabs as air supply ducts.
Regenerative heat exchanger
Incoming
air into the
AHU
Operation of Main Building
Filter
Heater
Air passes through
hollow cores in the
ceiling slabs
Air enters the internal occupied space
Operation of Main Building
Recovers 87% of Ventilation
Heat Requirement.
Space for future
chilling
Out of the
building
Return air passes through
the heat exchanger
Return stale air is extracted
Fabric Cooling: Importance of Hollow Core Ceiling Slabs
Hollow core ceiling slabs store heat and cool at different times of
the year providing comfortable and stable temperatures.
Warm air
Winter
Day
Warm air
Heat is transferred to
the air before entering
the room
Slabs store heat from
appliances and body
heat
Air Temperature is
same as building
fabric leading to a
more pleasant
working
environment
Fabric Cooling: Importance of Hollow Core Ceiling Slabs
Hollow core ceiling slabs store heat and cool at different times of
the year providing comfortable and stable temperatures.
Cool air
Winter
Night
Cool air
Heat is transferred to
the air before entering
the room
Slabs also radiate heat
back into room
In late afternoon
heating is turned
off.
Fabric Cooling: Importance of Hollow Core Ceiling Slabs
Hollow core ceiling slabs store heat and cool at different times of
the year providing comfortable and stable temperatures.
Cold air
Summer
night
Cold air
Draws out the heat
accumulated during the
day
Cools the slabs to act as
a cool store the
following day
night ventilation/
free cooling
Fabric Cooling: Importance of Hollow Core Ceiling Slabs
Hollow core ceiling slabs store heat and cool at different times of
the year providing comfortable and stable temperatures.
Warm air
Summer
day
Warm air
Slabs pre-cool the air
before entering the
occupied space
concrete absorbs and stores
heat less/no need for airconditioning
Energy Consumption (kWh/day)
Good Management has reduced Energy Requirements
Space Heating
Consumption
reduced by 57%
1000
800
800
600
400
350
O
200
0
-4
-2
0
2
4
6
8
10
12
14
16
Mean |External Temperature (oC)
Original Heating Strategy
New Heating Strategy
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Life Cycle Energy Requirements of ZICER as built compared to
other heating/cooling strategies
Naturally
Ventilated
221508GJ
54%
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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Comparison of Life Cycle Energy Requirements of ZICER
300000
250000
Naturally Ventilated
200000
GJ
Comparisons assume
identical size, shape and
orientation
ZICER
Air Conditrioned
150000
100000
50000
0
0
5
10 15 20 25 30 35 40 45 50 55 60
80000
Years
Compared to the Air-conditioned
office, ZICER recovers extra
energy required in construction in
under 1 year.
GJ
60000
40000
ZICER
20000
Naturally Ventilated
Air Conditrioned
0
0
1
2
3
4
5
6
7
8
9
10
Years
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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
22
Performance of PV cells on ZICER
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Façade
16
Output per unit area
Roof
kWh / m 2
14
Little difference between
orientations in winter months
12
10
8
6
Façade
(kWh)
4
2
0
Jan Mar May Jul Sep Nov Jan Mar May Jul Sep Nov
2004
Roof
(kWh)
Total
(kWh)
2004
2650
19401
22051
2005
2840
19809
22649
2005
16%
façade
roof
average
14%
Load Factor
12%
Load factors
10%
8%
Winter
Summer
Façade
2%
~8%
Roof
2%
15%
6%
4%
2%
0%
Jan Mar May Jul Sep Nov Jan Mar May Jul Sep Nov
2004
2005
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Performance of PV cells on ZICER - January
Wh
%
100
100
Block1
90
90
Block 2
80
80
Block 3
70
70
Block 4
60
60
Block 5
50
50
Block 6
40
40
Block 7
30
30
Block 8
20
20
Block 9
10
10
Block 10
0
0
radiation
9
10
11
12
13
14
15
Time of day
All arrays of cells on roof
have similar performance
respond to actual solar
radiation
Radiation is shown as
percentage of mid-day
maximum to highlight
passage of clouds
%
Wh
The three arrays on the
façade respond differently
200
180
160
140
120
100
80
60
40
20
0
100
90
80
70
60
50
40
30
20
10
0
9
10
11
12
13
Time of Day
14
15
Top Row
Middle Row
Bottom Row
radiation
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Elevation in the sky (degrees)
20
18
16
14
12
10
8
6
4
2
0
120
8.00
9.00
150
10.00
180
210
12.00
13.00
14.00
Orientation relative to True North
11.00
15.00
240
16.00
Elevation in the sky (degrees)
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January
May
September
P1 - bottom PV row
February
June
October
P2 - middle PV row
March
July
November
P3 - top PV row
April
August
December
20
15
10
5
0
6.00
7.00
8.00
9.00
10.00
11.00
12.00
Time (hours)
13.00
14.00
15.00
16.00
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
Use of PV generated energy
Peak output is 34 kW
Peak output is 34 kW
Sometimes electricity is exported
Sometimes electricity is exported
Inverters are only 91% efficient
Inverters are only 91% efficient
Most use is for computers
Most use is for computers
DC power packs are inefficient
DC power packs are inefficient
typically less than 60% efficient
typically less than 60% efficient
Need an integrated approach
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
30
Conversion efficiency improvements
Before installation
1997/98
MWh
electricity
gas
oil
19895
35148
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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
Heat rejected
High
Temperature
High Pressure
Compressor
Condenser
Throttle
Valve
Evaporator
Heat extracted
for cooling
Low
Temperature
Low Pressure
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Conversion Efficiency Improvements
Adsorption Chilling
Heat rejected
Heat from external
source
High Temperature
High Pressure
Desorber
Heat
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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The Future:
Advanced Gasifier Biomass CHP Plant
UEA has grown by over 40% since 2000 and energy demand
is increasing.
• New Biomass Plant will provide
an extra 1.4MWe , and 2MWth
• Will produce gas from waste
wood which is then used as fuel
for CHP plant
• Under 7 year payback
• Local wood fuel from waste
wood and local sustainable
sources
• Will reduce Carbon Emissions of
UEA by a further 35%
Comparison of Carbon Emissions from Heating & Hot Water
CO2 Emissions from Heating and Hot Water
1400
CO2 Emissions kg/student
1200
1000
800
CHP
gas
oil
600
400
200
0
East Anglia
Bath
Loughborough
Essex
York
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Reducing Carbon Emissions at the
University of East Anglia
4000
150
2000
1000
0
CO2 emissions per sq metre
Reduction with biomass
kg/sqm
Reduction
with biomass
3000
100
50
0
1990
25000
2006
2009?
Total Annual CO2 emissions
20000
tonnes/annum
kg/student/annum
CO2 emissions per student
15000
10000
5000
0
1990
2006
2009?
1990
2006
2009?
When completed the
biomass station will
reduce total emissions
by 32% compared to
2006 and 24.5%
compared to 1990
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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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Managing the Climate Dimension
Thermal Comfort is important: Even in ideal environment 2.5% of people
will be too cold and 2.5% will be too hot.
Estimate heating and cooling requirements from Degree Days
180
160
140
Heating
Cooling
120
100
80
Index 1960 = 100
60
1960- 1965- 1970- 1975- 1980- 1985- 1990- 1995- 20001964 1969 1974 1979 1984 1989 1994 1999 2004
Heating requirements are ~10+%
less than in 1960
Cooling requirements are 75%
higher than in 1960.
Changing norm for clothing from a
business suite to shirt and tie will
reduce “clo” value from 1.0 to ~ 0.6.
To a safari suite ~ 0.5.
Equivalent thermal comfort can be achieved
with around 0.15 to 0.2 change in “clo” for
each 1 oC change in internal environment.
Data for UK
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Energy Consumption (kWh/day)
A Pathway to a Low Carbon Future for business
1000
800
600
400
O
200
0
-4
-2
0
2
4
6
8
10
12
14
16
18
o
Mean |External Temperature ( C)
Original Heating Strategy
1.
Awareness
2.
New Heating Strategy
Management
5. Offsetting
Green Tariffs
4.
Renewable Energy
3.
Technical Measures
42
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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