Experimental Performance of an R134a Automobile Heat Pump System Coupled to the Passenger Compartment

Abstract

This study presents experimental performance of an R134a automotive heat pump (AHP) system driven by a d iesel engine and capable of utilizing the heat absorbed from the ambient air, engine coolant and exhaust gas. The experimental setup was developed from the components of the air conditioning system of a compact-size car, and tested by changing the engine speed, engine load and air temperatures entering the condenser and evaporator. The steady-state and transient performance characteristics of the AHP system for each heat source were evaluated by applying energy analysis to the system based on experimental data. Then, the performance parameters of the AHP system for three different heat sources were compared with each other and with those of the baseline heating system. The results show that the AHP system using engine coolant provides higher heating capacities and air temperatures at the register outlet in the first five minutes of the tests. However, the baseline heating system usually performs better than the AHP system when the steady-state is achieved. The AHP system caused an increase in the engine brake specific fuel consumption within the range of 4–54% depending on the engine load.