Renewable energy products use heat from the outside air, the sun or wood fuel to heat homes, buildings and hot water. The range includes air source heat pumps and their hot water kits, solar thermal pump stations, controllers, expansion vessels and solar fluid, twin coil hot water cylinders, plate heat exchangers and buffer stores, and biomass pellet boilers and stoves for homes and larger buildings.
Heat pumps
An air source heat pump takes heat from the outdoor air and moves it into the heating and hot water system. Outputs are given in kW, and the heat pump should be sized to the heat loss of the building. Heat pumps run at lower flow temperatures than most boilers, and at those temperatures a radiator gives only about half its rated output, so radiators may need to be larger. In England and Wales, the Boiler Upgrade Scheme for heat pumps and biomass boilers requires an MCS certified installer.
Solar thermal and cylinders
Solar collectors heat a glycol-based antifreeze fluid that a pump station circulates through a coil in the hot water cylinder. A twin coil cylinder has two coils, one above the other: the lower coil takes the solar circuit and the upper coil the boiler or heat pump, which tops up the heat when the sun alone is not enough. Unvented cylinders must be installed by a competent person under Building Regulations Part G (G3).
Biomass
Pellet boilers and stoves burn wood fuel and need a suitable flue, and their installation must meet Building Regulations Part J. HETAS is the competent person scheme for solid fuel and biomass appliances. Any work on the refrigerant circuit of a heat pump needs an F gas certified engineer.
For circulators, see pumps; for hot water storage, see unvented cylinders.
