CRed Carbon 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 5 th October 2007 Solar Energy Opportunities CLA Renewable Energy Event 5 th February 2010 Solar Thermal Solar Photovoltaic What is likely performance of these technologies The challenges of integrating solar energy into buildings to make most effective use of the resource. 1

2 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 participants 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 2

Solar Collectors installed 27th January 2004 Annual solar collection kWh/annum The Broadsol Project 3

Technical Solutions: Solar Thermal Energy 4

Up to 15 installations were monitored at 5 miute intervals for periods up to 15 months Mean Monthly Solar gain for 11 systems Some 2 panel systems captured twice the energy in summer months as other 2 panel systems.. 3 panel systems 5

The Broadsol Project Three panel systems captured only 13% more energy compared to two panel systems Effective use is not being made of surplus in summer 6

Measured Overall System Efficiencies System Efficiency of 2 panel systems is generally higher than 3 panel systems 2 panel 3 panel 7

8 Tilt Angle variations are not significant in region 0 – 45 o Optimum orientation in East Anglia is SSW South West is as almost as good as South 8

More Solar Energy is Collected when Hot Water use is greater. Sky became hazy at ~ 11:00 Substantial hot water demand at 13:30 Normal heat loss from tank if there had been no demand shown in black kWh extra heat collected. Note: further demand at 18:30 leading to further solar collection. Even more solar collection would have been possible had collector been orientated SW rather than S BS27: 15/05/ kWh 0.911kWh 1.157kWh0.083kWh 9

Technical Issues requiring awareness raising: Solar Thermal Energy captured when combined with central heating Tank with small residual hot water at top of tank in early morning If Central Heating boiler heats up water – less opportunity for solar heating. Zone heated by solar energy 10

Technical Issues requiring awareness raising: Solar Thermal Energy Tank with small residual hot water at top of tank in early morning No hot water provided by central heating boiler. Gain from solar energy is much higher. More solar energy can be gained if boiler operation is delayed. Boiler ON/OFF times should be adjusted between summer and winter for optimum performance 11

Technical Solutions: Solar PhotoVoltaic Zuckermann Institute for Connective Environmental Research. (ZICER) Low Energy Building of the Year Has heat demand ~ 20% of building of its size: 34 kW of Solar Photovoltaic on roof and facade 12

Mono-crystalline PV on roof ~ 27 kW in 10 arrays Poly- crystalline on façade ~ 6.7 kW in 3 arrays ZICER Building Photo shows only part of top Floor 13

Peak Cell efficiency is ~ 9.5%. Average efficiency over year is 7.5% Mono-crystalline Cell Efficiency Poly-crystalline Cell Efficiency Efficiency of PV Cells Peak Cell efficiency is ~ 14% and close to standard test bed efficiency. Most projections of performance use this efficiency Average efficiency over year is 11.1% Inverter Efficiencies reduce overall system efficiencies to 10.1% and 6.73% respectively 14

Load factors Façade: 2% in winter ~8% in summer Roof 2% in winter 15% in summer Output per unit area Little difference between orientations in winter months Performance of PV cells on ZICER 15

All arrays of cells on roof have similar performance respond to actual solar radiation The three arrays on the façade respond differently Performance of PV cells on ZICER 16

Orientation relative to True North 17

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Arrangement of Cells on Facade Individual cells are connected horizontally As shadow covers one column all cells are inactive 19 If individual cells are connected vertically, only those cells actually in shadow are affected. Cells active Cells inactive even though not covered by shadow

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? 20

21 Benefits from Feed In Tariffs: From 1 st April 2010 TechnologyScale installations 01/04/10 – 31/03/11 (p/kWh) **** installations 01/04/11 – 31/03/12 (p/kWh) **** installations 01/04/12 – 31/03/13 (p/kWh) **** PV <4kW (new build) PV<4kW (retrofit) PV4-10kW PV10–100kW PV100kW– 5MW PV Stand alone systems Tariffs for Generation In addition it is proposed that electricity exported will benefit from an export tariff which is currently proposed at 3p*** per kWh Revised Tariffs as published by DECC on 1 st February 2010

Solar Thermal –Installations can reduced energy requirements for hot water. –But careful consideration of timing of normal hot water system is needed for optimum performance. Solar PV systems –Need care in design to ensure optimum performance. –Consider integration of use via INTERNAL DC networks to avoid unnecessary losses. The new Feed in Tariffs should help economics, but optimum returns will come for early adopters. Conclusions Lao Tzu ( BC) Chinese Artist and Taoist philosopher “If you do not change direction, you may end up where you are heading.” 22