Since the conventional refrigerant R-134a is being phased out due to its high global warming potential, finding a suitable replacement refrigerant and a system design is of great importance. However, most of the alternatives are either flammable or expensive. Therefore, to ensure the safety of passenger and reduce the refrigerant charge, a secondary loop system with coolant loop on both condenser and evaporator side was proposed. The performances of this system using R-134a, R-152a, and R-1234yf were evaluated and compared to that of conventional direct expansion system using R-134a under the US06 driving cycle condition. The results show that the coefficient of performance of the secondary loop system is significantly lower than that of direct expansion system due to high pressure ratio and high compressor revolution speed. For the secondary loop system, the R-152a has better performance than R-1234yf and is a more suitable alternative refrigerant.