By installing a 3.96 kWp photovoltaic array and A 40 tube solar thermal collector, the owners of this detached rural property sought to use their large south facing roof to reduce their dependence on gas and electricity from utility companies. The solar thermal collector is able to satisfy the majority of their hot water requirements, whilst the photovoltaic array is able to offset a substantial proportion of their electricity consumption.


The solar thermal collectors are linked via a pump station to a 220 litre vented triple coil hot water cylinder. This has two solar coils in the top and bottom of the tank. Once the upper part of the tank reaches its target temperature, further solar gain is diverted into the lower tank. A gas-fired boiler tops up any shortfall in the solar contribution. The solar circuit also includes a bypass radiator mounted in the roof space into which excess heat is automatically diverted once the whole of the cylinder is up to temperature during peak irradiation or holidays.


A 3.96 kWp photovoltaic array comprised of 20 Sharp NU180E1 modules with a Diehl Platinum 3800S inverter linked via a sub-distribution board in the garage.  It is estimated that the array will generate about 3,608 kWhs of electricity per annum.