An air source heat pump with an advanced cycle for heating buildings in Beijing

It is difficult for an air source heat pump (ASHP) system to provide enough heat for heating buildings with high working efficiency when it runs at low ambient temperature. An advanced ASHP system that, in the paper, composes a main refrigerant circle and a bypass circle would supply a lot of heat for the buildings in Beijing at same working condition. In the system, the bypass refrigerant can be used to increase the density of refrigerant at the inlet of the hermetic compressor employed in refrigeration cycle, and so, the advanced ASHP could appear relative high efficiency even when it runs at low ambient temperature. The assistant throttle apparatus in the bypass circle is a part of capillary that was enlaced tightly around to the compressor. The capillary can be used to reuse the heat from surface of the compressor. Compared with a traditional system, the advanced ASHP system could provide three times heat capacity and more than 35% of efficiency at the working condition −10 °C.