For a running chiller. Under ambient conditions, the load has become constant. At this time, the condensing heat load is also fixed. The temperature difference between the inlet and outlet water is specified to be 5 ° C, and the amount of cooling water must also be a certain value and the flow rate is inversely proportional to the temperature difference between the inlet and outlet water. Therefore, the operation of the chiller. As long as the temperature difference between the inlet and outlet of the cooling water is specified, this flow rate is usually controlled by the pressure drop of the cooling water entering and leaving the condenser. Under standard conditions, the condenser inlet and outlet pressure drop is set at 68.6 kPa (0, 7 kg/cm).
In the actual operation of the cooling water system, there are often the following misoperations:
(1) The water inlet valve of the condenser on the unit that does not need to be opened is not turned off before starting the water to cause drowning. A part of the cooling back water flows away from the condenser of the startup group, which reduces the flow of cooling water in the condenser of the running unit, causing the condensing pressure to rise. The operating current of the main unit increases. The cooling capacity of the unit decreases, and the unit will be seriously Stop running. It wastes electricity, reduces cooling effect, and easily damages equipment.
(2) Due to the previous misoperation, the condensing pressure of the main engine and the effluent temperature of the cooling water rise. Cause the operator to make a misjudgment. I mistakenly think that the cooling water is not enough to open the condenser inlet valve and the cooling water pump outlet valve, and some also increase the cooling tower fan, resulting in increased power consumption of the pump and cooling tower fan.
(3) What's more, blindly add a cooling water pump. Although the addition of the cooling water pump can reduce the cooling water temperature and the condensing pressure, after all, the power of one pump is wasted. Therefore, the correct operation method of the faulty cooling water system is:
1) It is not necessary to operate the unit condenser inlet valve to close before starting the machine. Prevent drowning.
2) Open the inlet and outlet water valve on the condenser of the unit to be operated (the general outlet valve is normally open, the inlet valve is opened and closed as needed. The condenser and the evaporator are the same). Turn on the corresponding cooling water pump. Adjust the inlet and outlet pressure drop of the condenser. Up to 68.6 kPa (0.7 kg/cm:) (the pressure drop is based on the principle of overcoming the resistance of the pipeline. The lower the power saving effect is better).
3) If the pointer of the condenser inlet and outlet water pressure swings too large, it means that there is air in the cooling water system. It is necessary to discharge the air until the pressure gauge indicates normal and continue the next operation.
4) In operation, no matter how many units are opened, it is a cooling water pump to one main unit (the matching is the same).