ABSTRACT
This chapter shows that some existing heating systems can run on wholly or partly renewable fuels. It deals primarily with hot water and space heating for buildings. Solar thermal energy is used primarily for hot water, because of seasonal mismatch between sunshine availability and space heating needs. Flat plates are effectively large radiators coloured black to maximise heat absorption. Heat can be extracted from the ambient atmosphere using a device called an air source heat pump. Heat pumps generally deliver their output at lower temperature than fuel burning boilers but, unlike the latter, operate continuously. The UK government was one of the first to introduce a comprehensive support scheme for renewable heat. Bioenergy is considered sustainable, unlike fossil fuels, because it is derived from grown feedstock. Many crops and waste streams can be used for bioenergy; some are specially grown, and some by-products from other activities.
