Defrost, Low Carbon, PCM Thermal Storage.
A new system for defrosting the air coils of freezers is described - the patented Frigesco(TM) system. The net energy consumption of this system is close to zero and so it effectively reduces the overall energy consumption of a freezer system by the amount of energy normally used by electrical or hot gas defrost systems. The principal of operation is that heat available from the hot liquid refrigerant leaving the condenser (normally wasted) is stored in phase change material and then used when a defrost is needed. The subcooling of the liquid refrigerant by passage through the heat store increases the refrigeration effect to the extent that the post-defrost re-chilling of the freezer body, circulating air and contents is virtually energy neutral. Results of applying this system to a walk-in frozen food store and also a frozen food retail display cabinet under laboratory conditions will be presented. For example in the case of the RDC which was normally electrically defrosted 6 times a day we have shown a 40% reduction in energy consumption when the Frigesco system was introduced into the refrigeration circuit. It is anticipated that results from in-store trials (currently about to start) of the walk-in store application will be available for inclusion in the paper.