Energy saving strategies in refrigeration systems by defrost management

Abstract

Defrosting at evaporator panel is one of working cycles in freezer. Power consumption in defrosting does not meet the objective of using freezer, therefore, the approach to decrease power consumption in defrosting is one strategy for energy saving. Normally, the cycle of defrosting in freezer is a constant time that specify by referring to the highest humidity period. With this control concept, the problem of temperature exchange is not occurred from ice accumulation at evaporator panel but it makes the over necessity of defrosting process in the low humidity season and cause the unnecessary power usage in freezer. This thesis presents the control approach for defrosting by using the difference of the temperature at evaporator and the temperature at chilling area. By using this approach, the defrosting process is operated depend on load and the fan is on or off relate to defrosting time. Test results demonstrate that about 12% of power can be saved by this control approach when compared to constant time control.