겨울철 냉동설비의 작동 문제점 및 대책
Operation problems and Countermeasures of refrigeration equipment in winter
In Winter, when the outdoor temperature is wet and low, and the condensation pressure has a great influence on the performance of the refrigeration system.
When the condensation pressure (or condensation temperature) is high, the compression ratio increases.
And the volumetric efficiency of the compressor decreases, resulting in the reduction of refrigeration capacity and the increase of power consumption. The higher the exhaust temperature and the higher the condensation pressure, the greater the adverse effect.
The phenomenon of high condensation pressure mainly occurs in Summer. At this time, the condensation pressure should be reduced as much as possible to ensure the economy and reliability of the system operation.
However, in winter, the condensation pressure of refrigeration equipment may be too low.
When the condensing pressure is too low, the pressure difference between the front and back of the expansion valve is too small, and the capacity of the expansion valve is reduced, resulting in the insufficient liquid supply capacity of the system refrigerant, the lack of liquid in the evaporator, and the refrigeration capacity of the system is greatly reduced, and the unit is protected under low pressure. Therefore, it is necessary to control the condensing pressure in a reasonable range, otherwise the refrigeration device will have frequent low-pressure alarm or low suction pressure alarm.
In order to avoid the winter operation risk of the cooling water system, we can start from ：the cooling tower equipment, cooling tower operation strategy and the end pipeline setting.
To avoid the winter operation risk through the equipment side anti freezing, cooling tower start-up and shutdown and pipeline optimization design.
1.There are TWO parts of antifreeze in the place of perennial operation or partial operation:
Spray Water System and Internal Circulating Water System (softened water).
For the anti freezing problem of spray water system, an electric heater is usually added in the water pan, which is generally started when the spray water is lower than 5 ℃ and stops when the spray water is above 8 ℃.
The temperature probe transmits the signal to the control cabinet to automatically control the start and stop of the electric heater. The power selection of electric heater depends on circulating water volume and external air temperature.
2.Ethylene glycol solution or electric heating equipment can be added to prevent freezing of internal circulating water system.
The freezing point temperature of glycol solution should be selected below the local historical minimum temperature.
For the larger cooling system, we can consider digging a pool to put the spray water into it, which can save the power consumption due to electric heating operation.
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