Heat pump for domestic space heating - uses extract ventilation air as source and has gas boiler for supplementary heating

摘要

A heat pump has an evaporator over which a fan blows air extracted from the space being heated. The condenser heats water which is circulated through control valves to space heating radiators. The heating water can also circulate through a gas fired boiler. Its flow is controlled by the valves so that the heat pump using vitiated air is used alone in mild conditions and the gas boiler is added in severe conditions only. The flue gases of the boiler are added to the air blown over the evaporator.