Active solar thermal space heating
It is quite possible to entirely heat a building year round using solar energy providing you have a very large, very well insulated interseasonal heat store, most likely of water. An early example of this was the visitor’s centre and bookshop at the Centre for Alternative Technology at Machynlleth in Wales. A photo (fourth down in the middle) from 1975 shows the underground water tank heat store being lined with a membrane. The water used to collect the heat was pumped over the whole of the roof and allowed to run back into the store via gutters. This worked quite well for nearly three decades. The building has recently been entirely replaced.
Probably the best method to transfer the heat back into the building is via a pumped underfloor heating system because it can work well at lower temperatures and the water store temperature will be lowest around February/March when heat is needed most.
Undertaking this type of project would require considerable research and advice as very few schemes have been built.
Article on solar heating improvements to existing buildings including second homes
books :
Solar Energy Houses : Strategies, Technologies, Examples
by Anne-Grete Hestnes, Robert Hastings and Bjarne Saxhof
