AN ANALYSIS OF A NEW TYPE REFRIGERATION CYCLE (MICLOSS)

摘要

We have developed a new type refrigeration cycle, which has greatly enhanced the efficiency for refrigeration cold storage equipment, room ACs, refrigerators, display cases, and air conditioning equipment. The development of MICLOSS has aimed at improving the energy efficiency ratio (EER) during standard refrigerating or air conditioning equipment operation along with improving the SEER. Energy losses under compressor starting/stopping are usually considered to amount to 20 or 25% of the total energy consumption. We conducted quantitative analyses of the operation of refrigeration cycles in connection with the lowering of the efficiency under nonsteady (transient) operating conditions, and as a result the following findings were made: The condition of the refreigerant under pressure - which corresponds to the refrigerating or air conditioning capacity of the compressor - undergoes a change when the compressor is stopped. When the compressor is restarted, there is a time lag before pressure reaches the required level for steady (normal) operation. As a result, during this period of time the compressor capacity is not fully utilized, and the subsequent loss of energy leads to a lowering of the machine efficiency. Subsequently, we moved to remedy this situation by developing a new refrigeration cycle which would reduce the period required for the pressure within the compressor to regain its 'pre-stop' level to a minimum. This new refrigeration cycle is a conventional cycle plus current cutoff and on/off elements (see Fig.1 and Fig.2). The operating principles are as follows: When the compressor is stopped, the current cutoff element and the on/off element combine to close the refrigerant circuit, thus dividing the refrigerant into high- and low-pressure segments and maintaining both at their 'pre-stop' levels. Concurrently, the current cutoff element connects the bypass circuit of the compressor to equalize the compressor's discharge (high) pressure with that of its suction (low) pressure.