Experimental investigation of a CO2 automotive air conditioner

In this study, a CO2 automotive air conditioner prototype was designed and constructed. The compressor was of swash plate design; the gas cooler and evaporator were made of fin-tubes; a manual expansion valve and an internal heat exchanger accumulator were used. The lubricant, the CO2 charge, the evaporator outlet pressure, the compressor speed, the air inlet temperature and flow rate of the gas cooler and the air flow rate of the evaporator were varied and the performance of the prototype was experimentally investigated in detail. The cooling capacity, compressor power consumption, CO2 mass flow rate, and COP value were analyzed. The experimental results showed that the CO2 system performance was greatly affected by different lubricants; the CO2 system performance was sensitive to the mass charge; the high side pressure affected the system performance greatly and a high side pressure controller was needed.