The chiller operates under standard operating conditions. The return temperature of the condenser is 30 ° C and the outlet temperature is 35 ° C. For the operating chiller, the environmental conditions, load and cooling capacity have all become fixed values. At this time, the condensing heat load is undoubtedly also a fixed value. The standard stipulates that the temperature difference between the inlet and outlet water is 5 ° C, and the cooling water flow rate must be a certain value. And the flow rate is inversely proportional to the temperature difference between the inlet and outlet water. Therefore, the chiller operates under standard conditions, as long as the temperature difference between the inlet and outlet of the cooling water is specified. This flow is usually controlled by the cooling water pressure drop into and out of the condenser.
Under standard operating conditions, the outlet pressure drop of the condenser is adjusted to about 0.75kgf / cm2. The pressure drop setting method is also to adjust the opening degree of the cooling water pump outlet valve and the condenser inlet and outlet pipe valve opening.
In order to reduce the power consumption of the chiller, the condenser temperature should be reduced as much as possible. There are two possible measures: one is to reduce the return water temperature of the condenser, and the other is to increase the amount of cooling water.
For centrifugal chiller, high or low condensing pressure will cause surge. In the case of a centrifugal chiller, it should be noted that the difference between the condensing pressure and the evaporation pressure should not be too small, and it should meet the requirements to prevent surge, otherwise, surge will occur. In the autumn when the temperature is low, it is more advantageous to run the reciprocating chiller because the condensing pressure is lower and the power consumption is greatly reduced.