Why does glycol air cooler, glycol evaporator need defrost?
After glycol evaporator unit working a little while, it should be have frost on tube and fin.
It case heat transfer coefficient decreased. So the users need to use defrost system regularly.
VRcooler do have different defrosting methods for glycol air cooler.
Hot gas defrost
In small and medium freon refrigeration systems commonly used method of electric heating
defrost. Inserted heat pipe in the air cooler or evaporator. When start defrosting system
need to stop the operation of the air cooler, and close the valve for
the liquid, and then turn on the power of the heating tube, then the air cooler defrosting.
After the frost melts, turn off the power of the electric heating tube, start the
compressor, open the liquid valve properly, and resume the operation of the glycol air cooler.
This method consumes more energy, cold room temperature fluctuations are also large.
However, the defrost is convenient, easy to operate and easy to realize automatic
Hot gas defrost
Hot gas defrost (hot ammonia defrost or hot freon defrost) is that use the high temperature
refrigerant gas discharged from the compressor, first through the oil separator then
insert the evaporator to melt the frost layer.
The hot working gas emits heat and then condenses into liquid, which is discharged into
the liquid discharging bucket or the low pressure circulating liquid tank together with
the original oil in the evaporator. This method defrosting effect is good, a short time,
low labor intensity, however the operation is more complicated, it need to stop cooling
Water defrost use of sprinkler water spray to the outer surface of the frost layer on
evaporator, use the heat of the water to melt defrost. Advantage is simple operation,
time is short, it is a very effective defrosting method, however it is only limited to
the air cooler with drain pipe, and the cold temperature is usually above -4 ℃.