Development of World’s First Inverter Driven Commercial Freezer with CO2 Refrigerant by SANYO
Conventional CO2 refrigerant circuit become supercritical plus the coefficient of performance (COP) drops to less than HFC based refrigerant circuit when operating under high ambient temperatures such as summer temperature of above 30 degrees Celsius. In response to overcome this problem, Sanyo Electric developed a world’s first inverter driven commercial freezer with CO2 refrigerant. The new freezer was developed based on Sanyo’s patented split cycle which uses company’s proprietary Two Stage Rotary CO2 Compressor resulting in significant improvement in COP exceeding the performance of HFC based refrigerant circuit.
Sanyo has achieved the efficiency of 20 to 30 percent using a split CO2 refrigeration cycle in comparison to a non-split cycle. The new technology shows a better COP than HFC refrigerant circuit when the evaporation temperature is -30 degrees Celsius or lower. The new technology is able to reduce customer’s CO2 emissions resulting from electrical consumption by up to 15%. Given that there are approximately 170,000 commercial refrigerant/freezer shipped every year, replacing them with the new freezer would translate to reduction of 14,000 tons of CO2 emission per year. CO2 refrigerant in comparison to HFC based refrigerant requires about four to ten times cycle pressure which translates to large difference in pressure between the high and low pressure stages of the cycle which requires the parts of the refrigerant to be built much stronger in order to endure the pressure conditions, in addition to greater motor torque. The need for part strength and motor torque in two stage pressure design is about half in comparison to single stage compression, leading to commercialization of such freezers.
source
