Parallel compressor selection and configuration method for preventing compressor from being frequently started up and shut down

Abstract

The invention discloses a parallel compressor selection and configuration method for preventing a compressor from being frequently started up and shut down. The method comprises the following steps of: 1, calculating calculation adjustment coefficients of performance parameters of the compressor for transformation from nominal conditions to design conditions; 2, calculating a curve of change of the refrigerating capacity and power consumption of a direct-current variable-frequency compressor with operating frequency; 3, calculating performance parameters of an air conditioner unit under the design conditions; 4, determining the range of operating frequency of the direct-current variable-frequency compressor; and 5, selecting and configuring the parallel fixed-frequency compressor. The parallel compressor selection and configuration method for preventing the compressor from being frequently started up and shut down has the advantages that the accuracy of compressor selection is improved and the reliability when compressors with different output capacities are connected in parallel is increased.

Description

technical field [0001] The invention relates to the technical field of air conditioning, in particular to a matching method for parallel compressors that prevents frequent startup and shutdown of compressors. Background technique [0002] With the development of compressor parallel technology, the application of parallel compressors is becoming more and more extensive. Not only can multiple fixed frequency compressors be connected in parallel to form an air conditioning system with multi-level energy adjustment, but also multiple fixed frequency compressors and variable frequency compressors Parallel connection of compressors, or even parallel connection of multiple frequency conversion compressors to form an air conditioning system with greater total capacity, more capacity adjustment stages, and even stepless adjustment, which greatly improves the cooling capacity or heating capacity of the air conditioning unit in the air-conditioned room. The ability to change at will. ...

AI Technical Summary

Problems solved by technology

[0004] (1) The nominal performance parameters of the compressor provided by the existing compressor manufacturers are based on the nominal operating conditions stipulated in the compressor standard, that is, the condensation temperature is 54.4°C, the condensation subcooling degree is 8.4°C, and the evaporation temperature is 7.2°C , the evaporation superheat is 11.1°C, and the design condition of the air conditioning unit is that the condensation temperature is 48°C-50°C, the condensation supercooling is 5°C-8°C, the evaporation temperature is 4°C-10°C, and the evaporation superheat is 0 ℃~15℃, according to the refrigeration principle of the air conditioner, under the condition that the evaporating temperature is constant, the lower the condensing temperature, the greater the cooling capacity of the compressor. The actual capacity of the selected compressor is too large, which not only wastes the output potential of the compressor capacity, but also artificially increases the cost of the air conditioner unit, and there will be problems with frequent start and stop of the compressor

[0005] (2) The existing technology ignores the impact of the difference in output capacity between the parallel compressors on the stability and reliability of the air conditioning unit, especially when the DC variable frequency compressor and the fixed frequency compressor with a large output capacity difference are connected in parallel. The problem is particularly prominent. Due to compressor manufacturers' consideration of the development progress and market launch strategy of DC inverter compressors, the specifications and models of DC inverter compressors on the market are not complete, and the output capabilities of different specifications of DC inverter compressors vary greatly. For example, the current There is a certain brand of DC variable frequency compressors with specifications of 4 horses, 8 horses, and 12 horses, and fixed frequency compressors with specifications of 5 horses, 6 horses, and 10 horses. It can be seen that in a certain situation, if you do not consider When combined with the analytically selected compressor in parallel, the output capacity of the fixed frequency compressor may be greater than the output capacity of the DC inverter compressor at the maximum operating frequency. The compressor switching is not smooth, and the fixed-frequency compressor frequently starts and stops.

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