Heat pump air conditioning system and control method thereof

Abstract

The invention provides a heat pump air conditioning system and a control method thereof. The system comprises a compressor, a four-way valve, an indoor heat exchanger, a first throttling device, a second throttling device, 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, and the second throttling device and the defrosting heat exchanger are connected in series to form a defrosting pipeline. A refrigerant is divided into two paths after passing through the indoor heat exchanger and the first throttling device from an exhaust port of the compressor, one path flows back to the compressor through the main heat exchanger, and the other path enters the defrosting heat exchanger after being throttled through the second throttling device and then flows back to the compressor. And a refrigerant heating device is arranged on at least one of the exhaust pipeline, the air suction pipeline and the defrosting pipeline of the compressor. According to the heat pump air conditioning system, the frosting frequency of the main outdoor heat exchanger can be further reduced, the heat input of a refrigerant of the whole system can be enhanced, the heating duration is prolonged, and continuous indoor heat supply is achieved in the defrosting period.

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 external heat exchanger will be frosted, which increases the thermal resistance and wind resistance, which is not conducive to heat exchange and makes the performance of the air conditioner worse. In order to make the air conditioner operate normally, The air conditioner needs to be defrosted. The main defrosting method of the existing air conditioner is to switch the four-way valve to reverse the direction of the four-way valve. In this way, during the defrosting process, the indoor fan is stopped, which not only cannot provide heat to the room, but also The cooler has a lower refrigerant temperature and also absorbs heat from the room, lowering the ...

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Problems solved by technology

[0004] The applicant of this application applied for the patent 202010159387.0 in the early stage, which adopts the structural form of the main heat exchanger and the defrosting heat exchanger. The two are connected in series and a throttling device is connected between them to delay the frosting of the main heat exchanger. However, due to the temperature rise of the refrigerant after evaporating and absorbing heat in the main heat exchanger, its cooling effect may be limited when it passes through the defrosting heat exchanger, which results in limited air dehumidification ability and delays the process of frosting. Not particularly impressive

[0005] 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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