Method for controlling condensing pressure of refrigeration air-conditioning unit

Abstract

The invention provides a method for controlling the condensing pressure of a refrigeration air-conditioning unit. A cooling fan of the refrigeration air-conditioning unit comprises a group of variable frequency fans and at least a group of fixed frequency fans; the method comprises the steps: fan start control and fan operation control after the fan start; the fan start control comprises: step S11: detecting an ambient temperature T, and comparing the ambient temperature T with a preset temperature T1; step S12: when T is more than T1, starting the variable frequency fans to the maximum frequencies; when T is not more than T1, starting the variable frequency fans to the preset frequency corresponding to the ambient temperature T. According to the method for controlling the condensing pressure of the refrigeration air-conditioning unit provided by the invention, the start and operation of the fan can be controlled by distinguishing the ambient temperature, so as to be beneficial for realizing the precise control of the condensing pressure and realizing the stable and reliable operation of a unit.

Description

technical field [0001] The invention relates to the field of air-conditioning control, in particular to a method for controlling the condensation pressure of a refrigeration and air-conditioning unit. Background technique [0002] In the application occasions of air-cooled air-conditioning units, some occasions generate heat all year round and require long-term refrigeration, such as computer rooms and technological machine rooms. That is, these occasions not only need cooling in summer, but also need cooling in winter. [0003] Generally, there are three main design schemes for the condensing fan of the air-cooled air-conditioning unit, that is, the design scheme of the full fixed frequency fan, the design scheme of the fixed frequency + variable frequency fan, and the design scheme of the full frequency conversion fan. [0004] The full fixed-frequency fan design scheme cannot meet the cooling requirements of low ambient temperature (generally below 0°C) in winter, and th...

AI Technical Summary

Problems solved by technology

[0008] 2. Under high temperature conditions, after the compressor is started, the speed of the variable frequency fan is too slow, and the high pressure cannot be reduced, causing the unit to have high pressure protection

[0009] In general air-cooled units, the condensing pressure controlled by the outdoor condensing fan is generally a fixed value, but the controlled condensing pressure value is too low to cause low condensing pressure and low pressure, which makes the unit prone to low-voltage protection and low energy saving during operation. Difference

The controlled condensing pressure is high, the operating power of the whole machine is relatively high, and the energy saving performance has not been fully utilized

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