RECUPERATION OF COLD IN REFRIGERATING DEVICES

摘要

Approximately 15% of global energy consumption is used to drive refrigeration and air conditioning systems. Inefficient use of energy contributes to the wasting of valuable resources, thus improving energy efficiency in refrigeration is analyzed in many papers. The paper discusses the recovery of cold as one of the possibilities of improving the energy efficiency of refrigerating equipment. Generation of useful cold (low temperature heat, with temperature level below the ambient) requires the delivery of energy to drive refrigerating devices. A (useless) side effect of this process is the dew condensation of water vapour from the air and/or frosting of the surface of air coolers that operate at temperatures below the dew point and/or freezing. In addition, air coolers, which operate at temperatures below freezing, must be defrosted periodically in order to restore their performance. Most of defrost systems, such as electric, hot gas or reverse cycle defrost, requires the provision of additional energy to remove the cold accumulated in frost. Hence, the energy is consumed twice or even triple, when the frost forms, at its disposal, and in the redistribution of heat delivered during defrosting. The paper discusses the estimation of resources of cold that occur in refrigerating equipment and systems. There is shown the potential for the utilization of cold resulting from processes of dew condensation of water vapour from the air or frosting of the surface of an air cooler to increase the energy efficiency of refrigerating circuit. Schematic diagram of the experimental apparatus and the current results of research are presented.