Common mistakes in daily operation of industrial chillers

Common mistakes in daily operation of industrial chillers

The operation of the industrial chiller system works through three interconnected systems: refrigerant circulation system, water circulation system, and electrical automatic control system. It is applied to the cooling of plastic processing machinery forming molds, which can greatly improve the surface finish of plastic products, reduce surface marks and internal stress of plastic products, make the products do not shrink or deform, facilitate the demolding of plastic products, accelerate product shaping, and greatly improve Production efficiency of plastic molding machine. However, the operators often make the following errors and misoperations in daily operations:

　　 1. The operators of some air-conditioning host rooms did not strictly adjust the pressure drop of the chilled water inlet and outlet according to the operating parameters of the unit. It is often adjusted higher than the operating parameters, when the pressure drop is too high. It is not to close the outlet valve of the cold water pump. Instead, open the water inlet and outlet valves of the evaporator of another non-operating unit. Let the excess water away from the evaporator of another unit. In order to reduce the pressure drop, artificially increase the operating current of the cold water pump, resulting in a waste of electricity.

　　2, when starting up. The water inlet and outlet valves on the evaporator of the non-starting unit are not closed first, causing part of the cold water to flow away from the evaporator of the unit that cannot be opened, which affects the cooling effect of the unit under working conditions.

At this time, the flow of water that meets the 49kPa pressure drop of chilled water in and out of the A machine evaporator is 100kg/s. Since both the A and B evaporators have water flowing through, theoretically the frozen water flowing through the A machine evaporator is only 50kg/s, and the other 50kg /S flows away from the B machine evaporator. This kind of misoperation artificially reduces the cooling capacity of the unit, making it difficult to meet the requirements of various cold applications. At the same time, because the amount of water flowing through the evaporator of the A machine is reduced, the temperature of the A machine's outlet water will naturally be lower, which often gives the operator the illusion that the cooling effect of the unit is good. The pressure drop of the inlet and outlet water of the A machine evaporator will definitely decrease. Some operators do not close the water inlet valve of the evaporator of the B machine, and increase the pressure drop of the inlet and outlet water of the evaporator of the A machine. It’s a mistake to add a wrong one. After adding a cold water pump to solve the problem, although the pressure of the water inlet and outlet of the evaporator of the A machine is increased, it is not necessary to increase the cold water pump. This is equivalent to two cold water pumps. The work of the two evaporators is pure waste.

　　The reason for the above wrong operation is: the operator does not understand the operating principle of the unit, and is only satisfied with being able to turn on the main engine; the operator is afraid of trouble and is unwilling to adjust the water valve, so this operation is done for convenience.

　　 The correct operation method is:

　　 1. Before starting the machine, close the chilled water inlet valve of the non-operating unit to prevent water leakage;

　　2. Open the water inlet and outlet valves on the evaporator of the unit to be operated, turn on the corresponding chilled water pump, and adjust the pressure drop of the inlet and outlet water of the evaporator to about 49kPa.

　　 3. If the water pump starts. It is found that the pointer of the water inlet and outlet pressure gauge swings too much, indicating that there is air in the chilled water system and needs to be vented. After the pressure gauge indicates normal, the next operation can be continued;

　　4. No matter how many units are opened during operation, one chilled water pump corresponds to one unit.