Anti-freezing method and device for water chilling unit of air conditioning unit

Abstract

The invention discloses an anti-freezing method and device for a water chilling unit of an air conditioning unit. The method and the device aim at preventing frost cracking of an evaporator. According to the method, vapor-liquid two-phase-state pressure of a refrigerant of an inlet of the evaporator is controlled, and evaporation pressure in the evaporator is not lower than a certain value, so that the lowest temperature of the side, loading the refrigerant, in the evaporator is not lower than 0 DEG C. According to the device, a flow control device is connected between a compressor exhaust pressure pipe and an evaporator inlet pipeline, a pressure sensor is connected between an outlet of the evaporator and an air suction port of the compressor, and a control unit instructs to adjust the opening degree of the flow control device according to the difference between pressure after evaporation and target evaporation pressure. In comparison with the prior art, by controlling the vapor-liquid two-phase-state pressure of the refrigerant of the inlet of the evaporator, the evaporation pressure of the evaporator is not lower than the target evaporation pressure, the temperature t32 of the side, loading the refrigerant, in the evaporator is larger than 0 DEG C, and frost damage to the evaporator is prevented.

Description

technical field [0001] The invention relates to an operation method and device of an air-conditioning unit, in particular to an antifreeze method and device for an evaporator using water as a refrigerant. Background technique [0002] There are many types of evaporators for air conditioning units (units) in the prior art, one of which is an evaporator (heat exchanger) with water as the refrigerant, such as a plate heat exchanger, a casing heat exchanger, and the like. This kind of evaporator that uses water as the secondary refrigerant currently has a problem that is difficult for air-conditioning manufacturers to solve but has to face: freezing cracks. Frost cracking occurs on the water side of the heat exchanger. When the water on the water side of the heat exchanger freezes, the volume will increase, and the water side channel of the heat exchanger will be squeezed. When the freezing is severe, the water side will be squeezed. The channel causes the refrigerant (refriger...

AI Technical Summary

Problems solved by technology

Frost cracking occurs on the water side of the heat exchanger. When the water on the water side of the heat exchanger freezes, the volume will increase, and the water side channel of the heat exchanger will be squeezed. When the freezing is severe, the water side will be squeezed. channel, causing the refrigerant (refrigerant) side of the heat exchanger to communicate with the water side, water will enter the refrigerant system such as the fluorine system, causing irreparable damage to the unit

If water enters the fluorine system, basically all parts of the unit need to be replaced, which will cause considerable losses to users, and it is also a problem that every air-conditioning manufacturer does not want to happen.

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