Combined Heat and Power (CHP), sometimes referred to as cogeneration, is the simultaneous production of electricity and heat, both of which are utilised as produce, or, in the case of heat, stored for future use.
A District Heating (DH) scheme provides instead heat from a central heat source to more than one building, dwelling or customer and a Combined Heat and Power District Heating (CHPDH) scheme, which combined both together, utilises the heat generated by the CHP plant as the source for heat, which would otherwise be vented into the atmosphere, and distributes it to buildings, dwellings or in general customers.
Figure 1. District heating network (left) and house interface unit (right) (R.Wiltshire 2011).
The main element of a CHP system is amachine that produces electricity and heat.