Four-way valve bypass defrosting device

Abstract

The invention discloses a bypass defrosting device with four-port valves, which comprises a compressor, a gas-liquid separator, a high-pressure reservoir, at least two four-port valves, at least two groups of heat exchanging components in a condensing side, and at least two groups of heat exchanging components at an air side. The first port of each four-port valve is connected with the vent of the compressor, and the second port of each four-port valve is connected with one end of each heat exchanging component at the condensing side, the other end of the heat exchanging component is connected with the high-pressure reservoir; one end of each heat exchanging component at the air side is connected with the high-pressure reservoir, the other end of each heat exchanging component at the air side is respectively connected with the third port of the corresponding four-port valve, the input end of the gas-liquid separator is connected with the fourth port of each four-port valve, and the output end of the gas-liquid separator is connected with the intakeport of the compressor. The bypass defrosting device with the four-port valves has small system pressure fluctuation during defrosting, higher reliability and stability, good defrosting effect, short defrosting time and simple structure, and can implement heating and defrosting at the same time.

Description

【Technical field】 [0001] The invention relates to a four-way valve bypass defrosting device, in particular to a four-way valve bypass defrosting device for defrosting an evaporator in an air source heat pump unit. 【Background technique】 [0002] When the air heat pump unit is in heating operation in winter, frost will gradually form on the surface of the air-side heat exchanger (used as an evaporator at this time). Decrease gradually, and defrosting should be carried out at this time. At present, the commonly used defrosting methods mainly include the following types: [0003] 1. The four-way valve is used for reversing reverse cycle defrosting. Through the reversing of the four-way valve, the unit changes from the heating operation state to the cooling operation state, and the functions of the evaporator and condenser are interchanged, so as to achieve the purpose of defrosting. This defrosting method has the following problems: 1. The suction and discharge pressure chan...

AI Technical Summary

Problems solved by technology

This defrosting method has the following problems: 1. The suction and discharge pressure changes drastically, which has a large impact on the compressor, and the refrigerant return flow in the system is large; 2. The functions of the two devices are frequently switched, which destroys the thermal stability established in normal operation. , the system temperature fluctuates greatly; 3. The exhaust pressure of the unit drops suddenly at the beginning of defrosting, which will cause the compressor oil to jump, and the screw compressor that relies on the pressure difference to supply oil will cause poor lubrication of the compressor, and may damage the compressor in severe cases; 4. There is a low-pressure decay process at the beginning of defrosting, sometimes it decays below the low-pressure protection value, which affects the service life of the compressor, and the low-pressure decay will also make it difficult for the system to return oil

This defrosting method has the following disadvantages: 1. Due to the small sensible heat, the defrosting time is long; 2. The defrosting effect is poor, and the frost may not be defrosted when the ambient temperature is low

However, there are still the following disadvantages: 1. The diameter of the air return pipe is large, and the cost of installing a solenoid valve is relatively high; 2. In order to ensure that the system pressure fluctuation is small, the bypass volume should not be too large, so the defrosting time will be relatively long; 3. Electromagnetic Valve resistance causes suction pressure to drop, affecting heating performance

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