Heat pump air-conditioning system and control method thereof

Abstract

The invention provides a heat pump air-conditioning system and a control method of the heat pump air-conditioning system. The heat pump air-conditioning system comprises a compressor, a four-way valve, an indoor heat exchanger, a first throttling device, an outdoor heat exchanger and a second throttling device. The outdoor heat exchanger comprises a main heat exchanger and a defrosting heat exchanger. The defrosting heat exchanger is located on the air flowing upstream side of the main heat exchanger. The second throttling device is connected with the defrosting heat exchanger in series to form a defrosting pipeline. When the heat pump air-conditioning system is under a heating working condition, refrigerant starts from an exhaust opening of the compressor, passes through the indoor heat exchanger and the first throttling device and then is divided into two branches; one branch flows back into the compressor via the main heat exchanger, and the other branch is throttled by the second throttling device, enters the defrosting heat exchanger and then flows back into the compressor. According to the heat pump air conditioning system, the frosting frequency of the main outdoor heat exchanger in the heat pump air conditioning system can be lowered, the heat pump air conditioning system can be under normal heating work condition for a long time, and the work energy efficiency of the heat pump air conditioning system is improved.

Description

technical field [0001] The present application relates to the technical field of air conditioning, in particular to a heat pump air conditioning system and a control method thereof. Background technique [0002] When the heat pump air conditioner is used under low temperature conditions, after running for a period of time, the heat exchanger of the external unit will frost, which increases the thermal resistance and wind resistance, which is not conducive to heat exchange and deteriorates the performance of the air conditioner. In order to ensure the normal operation of the air conditioner, The air conditioner needs to be defrosted. The main defrosting method of the existing air conditioner is to switch the four-way valve and change the direction of the four-way valve. In this way, the indoor fan is stopped during the defrosting process, which not only cannot provide heat to the room, but also because the air flows through the indoor fan. The refrigerant temperature of the ...

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Problems solved by technology

[0004] However, for this air conditioning system, since the two outdoor heat exchangers are in the state of evaporating and absorbing heat during heating, the frosting frequency of the two outdoor heat exchangers is basically the same. The system needs to enter the defrosting control for a short period of time in the heating condition, which reduces the working energy efficiency of the air conditioning system, shortens the high-energy-efficiency running time of the heating condition, and reduces the working performance of the air conditioning system

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