New Generation Integrated Automotive Thermal System

The integration of a thermal system for automotive applications is presented in this study. The integrated system is able to cool or heat the passenger cabin of a conventional automobile. Most cars use separate cooling and heating systems to control the cabin interior air temperature for passenger comfort. The cooling system uses a standard refrigeration loop to cool the cabin in summer while the heating system uses the heat supplied from the engine to warm the cabin in winter. However, in recent automotive applications with alternative fuel sources, such as fuel cell or direct-injection diesel engines, the heat rejected from the engine is not sufficient to warm the cabin in cold climates. On the other hand, the cooling system which normally uses a vapor compression refrigeration cycle is able to cool the cabin as desired shortly after starting the engine in warm climates. A dual-loop cooling and heating system, which can work in both cooling and heating modes, may overcome this problem. The proposed system integrates both air conditioning and heat pump modes so that by simply switching a series of valves the cabin can be cooled or heated. In this research project, such a dual-loop automotive thermal system was designed and fabricated. Experiments were conducted and experimental data were collected and analyzed. This article focuses on the air conditioning (cooling) mode while the dual-loop system undergoes a cabin cooling process for summer conditions. The test results showed that the dual-loop system was a viable option resulting in acceptable coefficients of performance, as compared to the conventional automotive air conditioning system. Further optimization of the proposed integrated system is expected to enhance performance of the system.