This installation serves a listed farmhouse building and three nearby buildings that have been converted to provide visitor accommodation. Heat is generated by a 50kW log boiler and a 90-tube solar thermal collector array and is distributed to each of the buildings via a buried heat main.
Heat storage is provided by a 500 litre thermal store and a 3000 litre accumulator tank. During the heating season (Oct/Mar), when the log boiler is in operation, the two stores are directly connected. Outside of the heating season only the 500 litre heat store is used to supply heat loads; it is isolated from the larger tank to enable higher temperatures to be maintained by the solar collectors alone.
The log boiler is directly connected to the accumulator tank via a Laddomat charging controller which maintains efficient combustion and stratification of heat within the accumulator.
The solar collector array is mounted on a purpose-built wooden pergola. This is connected indirectly to the smaller thermal store through dual solar coils. Solar heat is directed firstly to the upper coil and then switched to the lower coil once the top of the store is up to temperature. This ensures that the most effective use is made of the contribution from the solar collectors.
The heat stores are linked indirectly to a heat distribution manifold via three 50kW heat exchangers. Programmer and thermostatic controls located in each of the buildings activate heat distribution.
The accumulator/thermal store in the boiler room is connected indirectly to a second thermal store in the farmhouse. It is also supplied with heat by a directly connected Stanley solid fuel range cooker. This thermal store supplies domestic hot water via a plate heat exchanger and is also directly connected to the central heating system.
