Running control method for fan group at condensing side of refrigeration system

Abstract

The invention discloses a running control method for a fan group at the condensing side of a refrigeration system. The fan group at the condensing side of the refrigeration system comprises a variable-frequency fan and at least one fixed-frequency fan. The control method comprises the following steps of: monitoring the high pressure P(high) of the system, judging with preset first reference value P1 and second reference value P2, judging whether the high pressure P(high) needs to be adjusted or not according to the interval where the high pressure P(high) is located, and realizing a stable adjustment on the high pressure P(high) by adjusting the running frequency of the variable-frequency fan at a preset speed while judging that the high pressure P(high) needs to be adjusted, thus avoiding the instability of the system due to the large changes of the high pressure P(high) in an instant, and then improving the running stability of the refrigeration system.

Description

technical field [0001] The invention relates to the field of control, in particular to a method for controlling the operation of a condensing side fan unit in a refrigeration system. Background technique [0002] At present, the fan on the condensing side of the refrigeration system mostly adopts an adjustable gear fan, and the start and stop of the fan is controlled by adjusting the gear of the fan. In this way, even if the fan is started at the lowest gear speed in the low temperature environment (≤-5°C), or the fan speed is increased during operation, it will cause a large instantaneous change in the high pressure of the refrigeration system. The low pressure of the refrigeration system is usually relatively stable, which will cause the difference between the high pressure and the low pressure of the refrigeration system to change greatly in an instant. [0003] For example, for the screw compressor used in the air-cooled screw unit, at least the difference between the h...

AI Technical Summary

Problems solved by technology

In this way, even if the fan is started at the lowest gear speed in the low temperature environment (≤-5°C), or the speed of the fan is increased during operation, the high pressure of the refrigeration system will change instantaneously. The low pressure of the refrigeration system is usually relatively stable, which will cause the difference between the high pressure and the low pressure of the refrigeration system to change greatly in an instant

[0003] For example, for a screw compressor used in an air-cooled screw unit, at least the difference between the high pressure and the low pressure must be above 4 bar to ensure that the unit returns oil to the compressor normally. When the difference between the high pressure and the low pressure is lower than this When the alarm pressure is reached, it may cause insufficient oil supply, burn the compressor, and affect the reliability of the unit

The change of the fan gear will cause the high pressure to drop suddenly, and the difference between the high pressure and the low pressure may approach 4bar during the reduction process, resulting in particularly large fluctuations in the whole system, affecting the safety and reliability of the whole machine sex

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