Screw type water chilling unit and control method and system thereof

Abstract

The invention provides a screw type water chilling unit and a control method and system thereof. The screw type water chilling unit comprises a condenser, a cooling water flow path, an evaporator, a chilled water flow path, a heat exchanger, a valve, a sensor group and a controller; cooling water of the cooling water flow path flows through the condenser; chilled water of the chilled water flow path flows through the evaporator; the heat exchanger is used for heat exchange between output chilled water and output cooling water; the valve is used for adjusting the flux of the cooling water entering the heat exchanger; the sensor group is used for detecting the temperature of the output cooling water and the temperature of input chilled water and the output chilled water; and the controller is used for controlling the valve and / or the heat exchanger according to the temperature of the output cooling water and the temperature of the input chilled water to regulate the temperature of the output chilled water and regulating the output load of the water chilling unit. By additionally arranging the heat exchanger and the valve in the water chilling unit, the output cooling water is used for adjusting the temperature of the output chilled water, the compressor does not need to be shut down, the water chilling unit can further reduce the output load range, or even zero load output is realized, and the technical problem that an existing screw type water chilling unit cannot achieve zero load output in the event of non-stop is solved.

Description

technical field [0001] The invention relates to the technical field of chiller control, in particular to a screw chiller and its control method and system. Background technique [0002] In some special occasions, the screw chiller has strict requirements on the load output adjustment range, and needs to realize 0% to 100% load stepless adjustment, or when the terminal load changes and the chilled water temperature rises, the unit needs to immediately increase the output load. [0003] At present, the load adjustment range of conventional screw chillers is 25% to 100%, and the use of refrigerant bypass can only expand the load adjustment range to 10% to 100%, and it is difficult to achieve 0% to 100% load output adjustment; [0004] During the operation of conventional screw chillers, the load output is generally adjusted by controlling the chilled outlet water temperature (or the chilled water inlet temperature). When the chilled outlet water temperature is lower than the se...

AI Technical Summary

Problems solved by technology

[0006] The embodiment of the present invention provides a screw chiller and its control method and system to solve the technical problem that the existing screw chiller cannot achieve zero-load output without shutting down

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