R744 System for Heating and Cooling of Automobiles – Analysis of Heat Pumps and Hot Gas Cycle
This paper describes the analysis of an air/air heat pump, a coolant/air heat pump and a hot gas cycle by means of experimental investigations and numerical simulations. All systems are based on the R744 refrigerant circuit of the air conditioning system, and they are therefore suitable for heating and cooling of the passenger cabin. It has been shown that quite large heating capacities of more than 2.4 kW can be achieved with the heat pump systems, even under unfavourable operating conditions (low compressor speed and low air fl ow rate). For the hot gas cycle, a maximum heating capacity of 1.1 kW was obtained at the investigated conditions.