Experimental Performance Analysis of an R134a Automobile Air Conditioning and Air-Sourced Heat Pump System

Experimental performance of an R134a automobile air conditioning (AAC) system capable of operating as an air-sourced automotive heat pump (AHP) has been evaluated in cooling and heat pump operations. For this aim, an experimental system was made up from the original components of an AAC system. The system was tested at five different compressor speeds. For cooling mode operations, the temperatures of the air streams entering the evaporator and condenser were maintained at Tevap,ai=25°C – Tcond,ai=25°C and Tevap,ai=30°C –Tcond,ai=30°C. On the other hand, for heat pump operations, the inlet temperatures were maintained at Tevap,ai=0°C – Tcond,ai=0°C and Tevap,ai=10°C – Tcond,ai=10°C. Using experimental data, performance parameters such as conditioned air stream temperature, compressor power, compressor mechanical power and compressor discharge temperature were evaluated in both operation modes. Furthermore, the cooling capacity and coefficient of performance for cooling (COPc) were evaluated in cooling mode, while the heating capacity and coefficient of performance for heating (COPh) were evaluated in heat pump mode. The cooling capacity and compressor power increased but COPc decreased with rising compressor speed. The system operating in heat pump mode provided sufficiently high heating capacity and conditioned air stream temperatures. Furthermore, the heating capacity increased but COPh decreased with rising compressor speed.