There are many ways to defrost
(1) artificial sweep cream
(2) water red cream
(3) hot salt water defrost
(4) electric defrost
(5) hot gas defrost
Most of our ammonia evaporator are use electric defrost due to it's easy to operation.
The evaporator that use electric frost, evaporator coil inserted in the electric heat pipe. Defrosting need to stop the operation of the ammonia evaporator, and close the valve for the liquid, and then turn on the power of the heating tube, for 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 evaporator.
This method consumes more energy, cold temperature fluctuations are also large. However, the defrost is convenient, easy to operate and easy to realize automatic control.