How is domestic hot water delivered and what type of hot water cylinder do I need?
Domestic hot water is normally stored at 60-65oC and as the heat pumps can generally only lift temperatures to around 45-50 oC, an additional water heating element will be required. This is usually an electric heating element in the water cylinder for boost. It is normal to try to use an offpeak tariff for hot water provision by the heat pump and this can reduced the costs for boost with appropriate control. Larger coil cylinders are required for heat transfer but both direct and indirect cylinder types are suitable. Some manufacturers supply high temperature heat pumps to satisfy total hot water demand but there will be a reduction in CoP. As a rule of thumb, ensure 200W/person is added to the design load if the heat pump is to be used for domestic hot water production.
