System and method for controlling gas injection quantity of multi-split air conditioning unit through enhanced vapor injection

Abstract

The invention relates to a system for controlling the gas injection quantity of a multi-split air conditioning unit through enhanced vapor injection. The system comprises a compressor, an oil separator, a four-way valve, an outdoor unit heat exchanger, a heating electronic expanding valve assembly, a plate type heat exchanger, a gas injection electronic expanding valve, a gas and liquid separator,an indoor unit heat exchanger and an indoor unit electronic expanding valve; a gas injection pipeline in the compressor is provided with a one-way valve; a first temperature sensor is arranged at thetop of the compressor; a second temperature sensor is arranged between an inlet on the evaporation side of the plate type heat exchanger and an outlet of the gas injection electronic expanding valve;a third temperature sensor is arranged between an outlet on the evaporation side of the plate type heat exchanger and a gas injection inlet of the compressor; and a high-pressure pressure sensor is arranged between the oil separator and the four-way valve. The control method comprises the following steps: performing on-off control on the gas injection electronic expanding valve according to the compression top overheat degree of the compressor and performing opening adjustment on the gas injection electronic expanding valve according to the overheat degree of the plate type heat exchanger, sothat the gas injection quantity is optimal, the operating stability of the unit is guaranteed and the energy efficiency of the unit is improved.

Description

technical field [0001] The present invention relates to a multi-connected air-conditioning system, in particular to a control system and a control method for the air injection volume of an air-injection enthalpy-increasing compressor in a multi-connected air-conditioning system, specifically a multi-connected air-conditioning unit air-injection increasing enthalpy and air injection Quantity control system and control method. Background technique [0002] As the ambient temperature decreases, the heating capacity and corresponding COP of the heat pump air-conditioning unit also decrease, but the number of consumers continues to increase as the external ambient temperature decreases. Therefore, some large air conditioner manufacturers have begun to consider adopting higher technologies to meet these demands, especially for commercial air conditioners. The technology of "injecting air to increase enthalpy" came into being. It also belongs to the secondary compression cycle of ...

AI Technical Summary

Problems solved by technology

The air injection volume is too small and the exhaust temperature is high, which will not only damage the compressor and affect the operation of the system, but also fail to exert its capacity and lose the effect of "injecting air to increase enthalpy"

If the air injection volume is too large, the compressor may run with liquid, which is also detrimental to the system.

Due to limited cost or technology, some manufacturers use capillary or solenoid valves for simple matching and opening control. Although these control methods are simple, it is difficult to achieve safe and stable operation under various load conditions.

Moreover, the application range of this method is narrow, and it cannot guarantee the stable operation of the system and the performance of the air conditioning effect.

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