CO2 HEAT PUMP HEATING AND WATER HEATER SYSTEM FOR COLD AREA
By incorporating a first-stage expansion intermediate-cooling cycle (gas injection) into a CO2 natural refrigerant heat pump, we have managed to achieve a significant improvement in heating capacity and energy consumption efficiency under low ambient temperature conditions. By combining this technology with previously fostered technologies developed for CO2 heat pump application including the heater-less ice formation prevention technology, the “direct heating” technology that provides direct heat exchange between the CO2 refrigerant and heating antifreeze, and the outlet hot water temperature transition control technology, we have developed a prototype of CO2 natural refrigerant heat pump heating and water heater system, which enables both heating and hot water to be delivered by a single system. This report describes the results obtained from performance evaluation tests conducted in our environmental test laboratory and from monitoring tests in a cold region (Hokkaido, Japan), and addresses the possibilities of this system for use in a heat pump system application.