Background to Solar Thermal Energy Opportunities The need for better control! N.K. Tovey ( 杜伟贤 ) M.A, PhD, CEng, MICE, CEnv 1 West Suffolk College 7 th June Recipient of James Watt Gold Medal for Energy Conservation

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

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

4 Technical Solutions: Solar Thermal Energy: Performance

5 Technical Solutions: Solar Thermal Energy Up to 15 installations were monitored at 5 minute 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

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 – including storage System Efficiency of 2 panel systems is generally higher than 3 panel systems 2 panel 3 panel 7

8 8 Tilt Angle variations are not significant in region 0 – 45 o in summer In winter optimum angles are between 45 o and 90 o Optimum orientation in East Anglia is SSW South West is almost as good as South Solar Thermal: Performance of Panels

9 9 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

Technical Issues requiring awareness raising: 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 Solar Thermal Energy captured when combined with central heating

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 Issues requiring awareness raising:

12 The Broadsol Project: Store Temperature Variations 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 1, if boiler supplied hot water before solar gain was sufficient, top of tank would be heated to 55 o C and reduce the potential solar gain by ~21%. On day 2, the loss would be negligible as temperature at top was already over 55 o C. If the store temperature throughout was as low as 20 o C having been drawn off for a bath late on previous evening the loss in potential solar energy gained for having early operation of the boiler can approach 40%. Day 1Day 2

What is needed An auxiliary controller. Located between normal central heating controller and solar controller Its function is to: To take predicted sunshine data from a weather source to prevent normal central heating boiler firing if adequate sunshine is likely to be available in next 2 – 3 hours. Bring on central heating hot water supply if no or limited sunshine or if temperature in tank is very low.

What is needed Solar Controller Normal Hot Water Controller Solar Controller Sensors Hot Water Sensors Auxiliary Controller Weather Information Etc.

Solar Rosette Diagram for East Norfolk/Suffolk Tilt N NE E SE S SW W NW N Azimuth <