Wide-temperature high-efficiency air source heat pump unit with anti-frosting function and operating method thereof

Abstract

The invention relates to an air source heat pump unit and an operating method thereof. A compressor is communicated with an indoor heat exchanger through a first on-and-off valve and a four-way reversing valve; the indoor heat exchanger is connected with a bidirectional liquid accumulator through a first one-way valve; one path is connected to the compressor through an anti-frosting coil, a third throttle valve, an outdoor heat exchanger, the four-way reversing valve, the bidirectional liquid accumulator and a second on-and-off valve; the other path is connected to the compressor through an electromagnetic valve, a second throttle valve and the second on-and-off valve; the first one-way valve is connected in parallel with the first throttle valve; the third throttle valve is connected in parallel with a second one-way valve; the compressor is communicated with the outdoor heat exchanger through the first on-and-off valve and the four-way reversing valve; and the outdoor heat exchanger is connected with the bidirectional liquid accumulator through the second one-way valve and the anti-frosting coil, and then is connected to the compressor through the first throttle valve, the indoor heat exchanger, the four-way reversing valve, the bidirectional liquid accumulator, and the second on-and-off valve. The air source heat pump unit has the advantages of wide temperature application range, frosting delay, and high-efficiency operation all year round.

Description

technical field [0001] The invention relates to an air source heat pump unit and an operation method thereof. Background technique [0002] At present, the operation effect of the air source heat pump is not ideal, the main reason is the poor low temperature adaptability of the air source heat pump, and another reason is the frosting and defrosting of the air source heat pump. [0003] From the perspective of the principle of vapor compression refrigeration, when the air source heat pump is applied in a cold area, as the outdoor ambient temperature decreases, the compression ratio of the unit increases, the volumetric efficiency decreases, the mass flow rate of the refrigerant decreases, and the heat supply decreases sharply. Excessive exhaust steam temperature will cause the unit to fail to operate normally or reduce the reliability of operation; coupled with the decrease of the outlet air temperature, especially the decrease of the indoor temperature during defrosting, it ...

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Problems solved by technology

[0002] At this stage, the operation effect of the air source heat pump is not ideal. The main reason is that the low temperature adaptability of the air source heat pump is poor. Another reason is the frosting and defrosting of the air source heat pump.

[0003] From the perspective of the principle of vapor compression refrigeration, when the air source heat pump is applied in a cold area, as the outdoor ambient temperature decreases, the compression ratio of the unit increases, the volumetric efficiency decreases, the mass flow rate of the refrigerant decreases, and the heat supply decreases sharply. Excessive exhaust steam temperature will cause the unit to fail to operate normally or reduce the reliability of operation; coupled with the decrease of the outlet air temperature, especially the decrease of the indoor temperature during defrosting, it seriously affects the comfort of the indoor environment

[0004] Frosting and defrosting of the outdoor heat exchanger lead to poor stability and reliability of the air source heat pump unit

The negative impact of frost on the operation of the air source heat pump unit is mainly manifested in two aspects: on the one hand, the formation of the frost layer increases the heat conduction resistance and reduces the heat transfer coefficient of the heat exchanger; on the other hand, the frost layer There is increased resistance to air flow through the finned tube evaporator, reducing air flow

As the frost layer thickens, the evaporation temperature will drop, the heating capacity will drop, the performance of the fan will decline, and the current will increase, which will make the air source heat pump unit unable to work normally.

[0005] It can be said that the low temperature adaptability of the air source heat pump is poor, and the problem of junction and defrost is the bottleneck restricting its efficient operation.

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