Defrosting Evaporators with Water
Author: George C. Briley, P.E. and Thomas A. Lyons, P.E.
There are a number of advantages for water defrost systems. These advantages include: The energy required for water defrost is less than for hot gas defrost. The only loads added to the refrigeration system are those required to return the coil to operating temperature and the losses to the surrounding area. This energy cost will vary with the application. Water defrost keeps coils clean except in very dirty applications (IQF Vegetable Freezers). If a refrigerant leak exists in a room where water defrost is used, stop the refrigerant flow to the unit; shut off the fans; and open the water defrost valve. The water will absorb the ammonia very rapidly. Caution: the water from the defrost may have to be diluted before it is discharged into a sewer. Water defrost, combined with hot gas defrost, can be employed where extremely rapid defrost is required.