Elham Village Hall is a heavy user of electricity, not least because heating is supplied by a 40 kW Dimplex ground source heat pump. Regular users of its facilities include a pre-school playgroup and adult education classes. The management team decided to offset as much of this usage as possible by installing a 26.66 kWp PV array.

By using high efficiency 310 Wp Canadian Solar modules we have been able to maximise the array capacity with 76 modules on the ESE facing roof pitch and 10 facing SSW.

On the ESE roof four 19 module strings are linked to the grid by 2 x SMA Tripower 10000TL-20’s. A 2.5 kWp SMA inverter connects the SSW array to the grid. For purposes of display and information, data from each of these inverters is linked via a router to the web-based Sunny Portal.

To maximise self-consumption a PV immersion switch diverts any surplus power to an immersion heater in the DHW storage cylinder. This improves the efficiency of the heat pump by minimising the time spent at elevated temperature for DHW.