Manual Versus Automatic Defrost

The defrost cycle in a refrigerator or freezer is critical to maintaining optimal performance and temperature stability. Certain techniques must be employed to periodically remove ice build-up on the unit’s evaporator coils and other surfaces. This function is important to maintain cooling capacity and efficiency, proper cabinet airflow, and system reliability. Any accumulation of ice can compromise the performance of the unit.

Performing the defrost function in refrigerators and freezers can be manual or automatic. Manual defrost units can be more energy-efficient than automatic defrost if the automatic defrost routine uses an external electrical heating element to melt the accumulated ice on the evaporator. While a unit using manual defrost ensures there is no rise in product temperature during the defrost cycle, it requires staff-labor to perform the function. Contents need to be relocated, the unit needs to be turned off and the ice and frost manually removed. The unit then needs to return to the set temperature prior to being put into operation again.

Automatic refrigeration defrost methods can include off cycle, electric, and gas. All methods can successfully accomplish melting the accumulated ice.

Vector units utilize a hot gas automatic defrost system, which defrosts the unit using the naturally occurring hot discharge vapor. “Hot gas defrost” is an efficient way to melt ice in the unit’s evaporator coils. This method allows for a shorter defrost time, about 3-5 minutes, and uses less energy than a standard electric automatic defrost. Instead of creating additional heat, as in the case of electrical defrost, the hot gas defrost process utilizes the hot vapor discharged by the compressor that has already been created in the unit so no additional heat is introduced. This defrost method, coupled with the fact that the Vector refrigeration system is top-mounted and completely external to the storage cabinet, results in very minimal temperature rise inside the storage cabinet during defrost.

Lab technicians and researchers know that it is important to maintain stable cabinet temperature to ensure the viability of biological materials and samples. Defrosting is an essential step in maintaining your laboratory cold storage.