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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

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Overview of advances within the sustainable built environment for

domestic buildings20th May 2009

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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

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• 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

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Solar Collectors installed 27th January 2004

Annual solar collection 750-910 kWh/annum

The Broadsol Project

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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.

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Solar Gain (kWh/day)

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1

2

3

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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

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Jan Mar May Jul Sep Nov

kWh

per

day

2007 2008

2009

Technical Solutions: Solar Thermal Energy

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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

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0

20

40

60

80

100

120

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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

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10

20

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60

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80

00 03 06 09 12 15 18 21 24Time of Day

Te

mp

era

ture

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5

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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

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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

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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

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Technical Solutions: Solar PhotoVoltaic

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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

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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.

Cells active

Cells inactive even though not covered by shadow

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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?

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Technical Solutions: The Heat Pump

Works best with underfloor heating

The potential for significant CO2 savings

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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?

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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.

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The Behavioural Dimension

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1000

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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.”