Method and system for judging liquid level in gas-liquid separator

Abstract

The invention provides a method and a system for determining the liquid level in a vapor-liquid separator. The method comprises the steps of obtaining a first saturation temperature, an inlet temperature, an outlet temperature, a second saturation temperature and an exhaust port temperature, calculating a vapor fraction superheat degree, a sucked-vapor superheat degree and an exhausted-vapor superheat degree, determining whether the vapor fraction superheat degree is greater than or equal to a first threshold, if the vapor fraction superheat degree is greater than or equal to the first threshold, determining whether the sucked-vapor superheat degree is greater than or equal to a second threshold, and if so, determining that no liquid-state coolant exists in the vapor-liquid separator, otherwise, determining that the liquid-state coolant exists and the liquid level of the coolant has a rising trend, but if the vapor fraction superheat degree is not greater than or equal to the first threshold, determining whether the sucked-vapor superheat degree is lower than the second threshold, and if not, determining that the liquid-state coolant exists in the vapor-liquid separator and the liquid level has a falling trend, otherwise, determining whether the exhausted-vapor superheat degree is greater than or equal to a third threshold, if the exhausted-vapor superheat degree is greater than or equal to the third threshold, determining that the liquid-state coolant exists, the liquid level has the rising trend and the liquid level is lower than a vapor suction port, and otherwise, determining that the liquid-state coolant exists in the vapor-liquid separator and the liquid level is higher than the vapor suction port; as a result, liquid return can be avoided according to the determination results.

Description

technical field [0001] The invention relates to the technical field of air conditioning, and more specifically, to a method and system for judging the liquid level in a gas-liquid separator. Background technique [0002] The compressor is a mechanical component used to transport gas and increase the pressure of the transported gas. It provides the core power for the air-conditioning refrigeration cycle system and is the "heart" of the air-conditioning system. Therefore, in order to ensure the normal operation of the air conditioning system, it is necessary to ensure the good operation of the compressor. However, liquid hammer phenomenon often occurs in the compressor, causing the limit valve plate and the stressed parts to be broken and deformed in a short period of time, resulting in the paralysis of the compressor. [0003] Since the liquid hammer phenomenon is caused by liquid return, etc., and liquid return refers to the phenomenon that the liquid refrigerant in the eva...

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Problems solved by technology

[0004] However, due to the limited volume of the gas-liquid separator, the liquid refrigerant that can be stored is also limited. Therefore, when the liquid refrigerant fills the gas-liquid separator, that is, when the liquid level of the liquid refrigerant in the gas-liquid separator is higher than that of the gas-liquid separator When the suction port is used, it will cause a large amount of liquid to return, resulting in liquid shock, causing serious wear and tear on the compressor rotor, cylinder and valve plate, and even causing the motor to burn out

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