Abstract
This study deals with a comparative experimental performance of an R134a automotive heat pump (AHP) system driven by a diesel engine and capable of using ambient air, exhaust gas and engine coolant as a heat source. For this aim, an experimental AHP system from the original components of an automobile air conditioning system was set up, and equipped with instruments for various mechanical measurements. The experimental system was operated at a broad range of engine speeds until the steady-state was achieved. Then, its performance at the end of five-minute operation period and its steady-state performance were determined based on experimental data. Finally, the results were presented in comparative graphics. It is revealed that the AHP system using engine coolant as a heat source has a superior fifth-minute performance over the AHP systems using other heat sources and over the coolantbased heating system. Although the AHP systems using exhaust gas and ambient air yield a better fifth-minute performance than the coolant-based heating system, all AHP systems perform poorer than this system after the steady state has been achieved.
Keywords: Automotive heat pump, air conditioning, refrigeration, R134a, diesel engine