External air source heat pump with thermostatic control - uses cylinder type fans to force external air over evaporator of heat pump and uses thermostat to switch fan motor speeds

摘要

The heat pump extracts energy from the outside air by force circulating the air across the evaporator coils of the heat pump, so that energy is extracted from the air to evaporate a refrigerant, which is then pumped through a condenser to give off the heat acquired. The heat flow is controlled by regulation of the speed of the cylinder type fan which force the external air over the evaporator. The air is drawn in to the centre of the fans and expelled radially. The fans are driven by electric motors in which speed is controlled by a circuit which uses a thermostat to switch the motors between two speeds, giving two different air flow rates.