Method for controlling stepless adjustment of water-source screw unit

Abstract

The invention discloses a method for controlling the stepless adjustment of a water-source screw unit, which belongs to the technical field of air-conditioning refrigeration. The method is implemented by carrying out pulse control on a loading valve or an unloading valve according to the measurement on the temperature t of discharged water performed by using a NTC (negative temperature coefficient) temperature measuring head. The method comprises the following steps: (1) startup: a main compressor is started for providing a sustained pulse for the loading valve, so that the main compressor carries out rapid loading; (2) loading: a controller transmits a loading pulse to the loading valve so as to carry out system loading, and accumulates the loading time; (3) keeping: the compressor does not carry out loading and lightening actions; (4) lightening: the controller transmits a lightening pulse to the loading valve so as to carry out system lightening, and accumulates the lightening time; (5) stoping: the unloading electromagnetic valve is powered on so as to ensure the compressor completes a shut-down process; and (6) forced stopping: the main compressor and a sub-compressor are powered off and shut down. In the method disclosed by the invention, the stepless adjustment of the water-source screw unit is controlled based on pulse time, the temperature control is correct, the stepless adjustment is reliable and efficient, and the safe and stable operation of the unit is ensured.

Description

technical field [0001] The invention relates to the technical field of air-conditioning and refrigeration, in particular to a control method for a steplessly regulated water source screw unit. Background technique [0002] The stepless adjustment of the screw unit is mostly controlled according to the outlet water temperature, and the energy output of the compressor is effectively adjusted according to the actual cooling load, reducing the frequent start and stop of the compressor, prolonging the service life of the compressor, and achieving the purpose of energy saving . [0003] In the prior art, the stepless adjustment of the slide valve usually uses a negative temperature coefficient NTC temperature probe to measure the outlet water temperature, and through pulse control of the loading and unloading valves, the energy can be adjusted steplessly in the energy-saving economic zone. The single compressor can continuously adjust the range from 50% to 100%, and the double c...

AI Technical Summary

Problems solved by technology

The existing stepless adjustment technology of water source of the screw unit still has the disadvantages of whether the compressor can reach full load after starting; when the compressor works in the holding area or full load area for a long time, there will be a retreat phenomenon caused by the oil leakage of the slide valve; When working under partial load for a long time, the unit will have the problem of poor oil return, which will affect the safety and reliability of the unit operation

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