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CRedCarbon Reduction
N.K. Tovey (杜伟贤 ) M.A, PhD, CEng, MICE, CEnv Н.К.Тови М.А., д-р технических наук
Energy Science Director CRed Project
Recipient of James Watt Gold Medal for Energy
Implementing New Technologies for an Energy Efficient Home
1
Overview of advances within the sustainable built environment for
domestic buildings20th May 2009
2
Advances within the sustainable built environment for domestic buildings
• Barriers and drivers to implement novel new technologies in domestic buildings.
• Domestic renewable energy technologies –
• Solar thermal
• Solar PV
• Combined heat and power (CHP)
• The challenges of integrating renewable energy sources into domestic buildings
3
• A Partnership between– Broadland District Council– University of East Anglia
• Launched by publicity with an open meeting attended by ~120
• Aims– To promote Solar Water Heating by a community to
enable bulk discounts• Required a minimum of 50 participans to sign up
within 3 weeks• Over subscribed in 22 minutes!• Subsequently 9 properties not found to be suitable
– To develop skills for installing Solar Hot Water Heaters in the region
Technical Opportunities: Solar Thermal:The Broadsol Project
4
Solar Collectors installed 27th January 2004
Annual solar collection 750-910 kWh/annum
The Broadsol Project
55
Mean Monthly Solar gain for 11 systems
3 panel systems
The Broadsol Project
0.0
1.0
2.0
3.0
4.0
5.0
F M A M J J A S O N D J F M A M J JMonth
kWh/
day
BSD1 BS01BS02 BS12BS14 BS16BS17 BS26BS27 BS29BS52
0
1
2
3
4
5
Feb
Mar
Ap
r
May
Jun
Jul
Au
g
Sep
Oct
Nov
Dec
Jan
Feb
Mar
Ap
r
May
Jun
July
Month
Dai
ly S
olar
Gai
n (
kW
h)
2 Panels
3 Panels
• Three panel systems captured only 13% more energy compared to two panel systems
• Effective use is not being made of surplus in summer
Some 2 panel systems captured twice the energy in summer months.
6
Solar Gain (kWh/day)
0
1
2
3
4
5
6
7
8
1 11 21 31 10 20 1 11 21 31 10 2030 10 20 30 9 19 29 9 19 29 8 18 28 7 1727 7 17 27 6 16 26 6 16 26 5 15 25 4 14 24 6 16 26 5 15 25 5
Sol
ar G
ain
(k
Wh
)
January February MarchApril May JuneJuly August SeptemberOctober November December
20092008
0
1
2
3
4
5
6
Jan Mar May Jul Sep Nov
kWh
per
day
2007 2008
2009
Technical Solutions: Solar Thermal Energy
7
0
5
10
15
20
25
30
35
40
45
jan mar may jul sep nov jan mar may
Syst
em E
ffic
ienc
y(%
)
bsd1
bs01
bs02
bs17
bs26
bs16
bs27
bs52
0
5
10
15
20
25
30
35
jan feb mar apr may jun jul aug sep oct nov dec jan feb mar apr may jun
Syst
em E
ffic
ienc
y (%
)
bs12
bs14
bs29
Measured System Efficiencies
System Efficiency of 2 panel systems is higher than 3 panel systems
2 panel
3 panel
88
0
20
40
60
80
100
120
140
160
180
Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov DecMonth
0 - Horizontal45o90o - Vertical
Tilt Angle variations are not significant in
region 0 – 45o
Optimum orientation in East Anglia is SSW
South West is as good as South
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The more Hot Water is used the more Solar Energy is Collected
• Sky became hazy at ~ 11:00• Substantial hot water demand at 13:30• Normal heat loss from tank shown in black• 1.157 kWh extra heat collected.• Note: small gain at 18:30. - even more would have been possible had collector been
orientated SW rather than S
00
10
20
30
40
50
60
70
80
00 03 06 09 12 15 18 21 24Time of Day
Te
mp
era
ture
0
5
10
15
20
25
30
35
40
En
erg
y p
rod
uc
ed
ea
ch
min
ute
(W
h)
energy
Extra Energy
collector
store
cooling
BS27: 15/05/2004
1.164kWh 0.911kWh
1.157kWh
0.083kWh
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Technical Issues requiring awareness raising:Solar Thermal Energy
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Tank with small residual hot water at top of tank
If CH boiler heats up water – less opportunity for solar heating.
If boiler is not on – more solar energy can be gained.
Boiler ON/OFF times should be adjusted between summer and winter for optimum performance
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Technical Issues requiring awareness raising:Solar Thermal Energy
11
Tank with small residual hot water at top of tank
In this case no boiler hot water heating is used.
Gain from solar energy is much higher
12
Store Temperature Variations
The Broadsol Project
Education of how to get best out of solar HW systems is needed..
Need to adjust timing of central heating boiler over late Spring, Summer and early autumn.
• On day one, if boiler supplied hot water as per normal top of tank would be heated to 55o C and reduce the solar gain by 21%.
• On day 2, the loss would be negligible, but if the store temperature was as low as 20oC the loss in solar energy can approach 40%.
Day 1 Day 2
13
Technical Solutions: Solar PhotoVoltaic
13
Zuckermann Institute for Connective Environmental Research. (ZICER)
Low Energy Building of the Year 2005. Has heat demand ~ 20% of building of its size: 34 kW of Solar Photovoltaic on roof and facade
14
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.
Cells active
Cells inactive even though not covered by shadow
15
Technical Solutions: Integrated use of PV generated energy
• Inverters are only 91% efficient
• Computers and other entertainment use DC. Power packs are inefficient
• LED lighting can use DC
• Need an integrated approach – houses with both AC and DC with heat recovery from central inverter/rectifier?
16
Technical Solutions: The Heat Pump
Works best with underfloor heating
The potential for significant CO2 savings
17
Preliminary data from installations in Norfolk.
• Objective data on comparisons between different strategies is needed.
• Identical houses with different low carbon strategies.
• Significant variation in electricity consumption.
0
10
20
30
40
50
HeatPump
Passive Solar Control
Co2
em
issi
ons
(kg/
m2/
year
)
electricity gas• Surprisingly, overall emissions from
houses with Ground Source Heat Pumps were inferior.
• But variation in appliance use between one house and another was large. Is this masking saving?
• Or was the collector loop correctly sized?
18
18
Micro CHP
Technical Solutions: CHP• Micro CHP plant for homes are being trialled.
• Replace the normal boiler
• A problem in summer as there is limited demand for heat – electrical generation will be limited. - Peak electrical import can occur at time of minimum demand.
• Backup generation is still needed unless integrated with solar photovoltaic? In community schemes explore opportunity for multiple unit provision of hot water in summer, but only single unit in winter.
19
The Behavioural Dimension
0
1000
2000
3000
4000
0 1 2 3 4 5 6
kW
h in
per
iod
No of people in household
Electricity Consumption
1 person
2 people
3 people
4 people
5 people
6 people
-100%
-50%
0%
50%
100%
150%
200%
1
% D
iffe
renc
e fr
om A
vera
ge
Variation in Electricity Cosumption1 person 2 people 3 people4 people 5 people 6 people
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Social Attitudes towards energy consumption have a profound effect on actual consumption.
Data collected from 114 houses in Norwich between mid November 2006 and mid March 2007
For a given size of household electricity consumption for appliances [NOT HEATING or HOT WATER] can vary by as much as 9 times.
When income levels are accounted for, variation is still 6 times
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• There are many opportunities of low carbon buildings.• Creative integrated solutions are needed.• Need to address the issue of the behavioral dimension
towards energy use.• Opportunities for community collective action – for cost
effective solutions should be explored.• Opportunities for more effective use of solar hot
water/CHP schemes warrant attention – Housing Associations?
Conclusions
Lao Tzu (604-531 BC) Chinese Artist and Taoist philosopher
“If you do not change direction, you may end up where you are heading.”