PLC energy saving control method of frozen water pump and cooling water pump in central air-conditioning system

Abstract

The invention relates to a PLC energy saving control method of a frozen water pump and a cooling water pump in a central air-conditioning system, which is realized through the following steps: (1) respectively installing a ratio adjusting valve on a frozen water system and a cooling water system; (2) starting the cooling water pump, starting the frozen water pump after the cooling water pump delays Tb, and then starting a freezer after the frozen water pump delays Ta, and causing the temperature difference of inlet and outlet water to approach to a set value through continuous adjustment of PLC; (3) keeping a freezing unit stopped if Th is less than Tk-delta; starting the freezing unit if Th is not less than Tk+delta t; and running the freezing unit by repeating the steps (1) and (2). The PLC energy saving control method has the advantage that the energy saving of the running of frozen water and cooling water systems is realized.

Description

technical field [0001] The invention relates to a central air-conditioning system, in particular to a control method for a chilled water pump and a cooling water pump in the central air-conditioning system. Background technique [0002] The design flow rate of the circulating pump in the central air-conditioning system is selected according to the flow rate (ie the maximum flow rate) plus a margin of about 10% under the worst working conditions, that is, the water pump system operates at the maximum water flow rate for a long time. Due to changes in ambient temperature and different heat loads of users, the actual load of the air conditioning system is much lower than the design value in 80% of the year, and the water required for operation is also much smaller than the maximum operating water flow. [0003] Generally, the design temperature difference of chilled water is 5°C, and the design temperature difference of cooling water is 5-7°C is the most ideal, but in fact, in ...

AI Technical Summary

Problems solved by technology

[0003] Generally, the design temperature difference of chilled water is 5°C, and the design temperature difference of cooling water is 5-7°C is the most ideal, but in fact, in most of the running time of the year, because the start-stop and operation of the pump do not change corresponding to the change of user load , the circulating water volume has been kept at the maximum value, the temperature difference between the chilled water and the cooling water is only 2-4°C, the water pump system has been working in the state of low temperature difference and large flow for a long time - the state of the big horse-drawn cart, the energy of the water pump is wasted while freezing The unit is operating under conditions of reduced efficiency and high energy consumption