Enhanced vapor injection air-conditioning circulating system and control method thereof

Abstract

The invention relates to a central air-conditioning system, in particular to a duct air conditioner, namely an enhanced vapor injection air-conditioning circulating system. A vapor injection side electronic expansion valve of the system is subject to discharge superheat control instead of vapor injection superheat control; high discharge superheat is guaranteed, and heating capacity of the system can be further improved by vapor injection; the system is especially applicable to variable frequency compressors; high heating capacity is kept even under different operating frequencies; the system operates stably and fluctuates little. The enhanced vapor injection air-conditioning circulating system comprises a controller, a compressor, a four-way valve, a vapor-liquid separator, an economizer, a solenoid valve and a coolant pipe. The compressor is a variable frequency compressor. The economizer is a plate economizer. The electronic expansion valve controls vapor injection. The vapor injection electronic expansion valve is subject to discharge superheat control instead of vapor injection superheat control; accordingly, high discharge superheat is guaranteed, and heating capacity of the system is further improved by vapor injection. The system is especially applicable to variable frequency compressors; the heating capacity is kept even under different operating frequencies; the system operates stably and fluctuates little.

Description

[0001] technical field [0002] The invention relates to a central air-conditioning system, in particular to an air duct machine. Background technique [0003] The cooling and heating effects of existing air conditioners and heat pump water heaters are limited by the ambient temperature. If in the heating mode, if the external ambient temperature is too low, the performance of the cooling system will be greatly attenuated, and the system will not be able to fully exert its due capacity and Energy saving, this defect makes the heat pump air-conditioning system unable to be used effectively in cold regions, which limits its scope of application. At present, the two-stage compression system of replenishing air and increasing enthalpy mostly uses fixed-frequency compressors. When variable-frequency compressors are used, it is difficult to accurately control the amount of air replenished to the compressor under different compressor frequencies and indoor and outdoor temperatures,...

AI Technical Summary

Problems solved by technology

[0005] First of all, the economizer used in the air supplementation and enthalpy increase system described in the above patent is a flash evaporator, which belongs to a pressure vessel. The application of a pressure vessel has strict requirements in terms of design and production, and the large volume is not convenient for the refrigeration system pipeline. design and connection; secondly, the above-mentioned patent adjusts the opening of the throttling device by controlling the superheat of the inlet and outlet of the refrigerant on the gas supply side of the flash evaporator. stable operation of the system

Finally, the compressor used in the above system is a rotary compressor, and the performance and stability of the rotary compressor are lower than those of the scroll compressor.

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