Design of Hybrid Air Conditioning System Using Phase Change Material for Commercial Sleeper Vehicles 2022-28-0448

Unfavorable climates, fatigue, safety & deprived sleep of driver’s leads to use of AC system for their quick thermal comfort during night with engine ON. This scenario is very critical from a human’s safety & vehicle functionality point of view. This also consumes an additional 10-15% of fuel requirements in AC running conditions. So, to address the social problems of driver’s sleep and pollution-free environment by reducing the use of fossil fuels, there is a need for alternative techniques for air cooling which work during engine OFF condition. Various alternative options for air cooling have been reviewed. Accordingly, the packaging flexibility of phase change material (PCM) technology makes it easy to implement, yet effective usage of large quantity stored PCM, needs optimization.

This paper proposes a design of a hybrid air conditioning system for sleeper commercial vehicles using a combined conventional compression and phase change material. The cold storage heat exchanger is designed for transacting heat between the three fluids—refrigerant, phase change material, and air. Thermal energy is stored in the PCM during vehicle operation by extracting latent heat from the conventional compression system's refrigerant and reused during engine shutdown by exchanging it with air for cooling. The designed cold storage heat exchanger is evaluated using a CFD tool by varying various parameters and optimizing for operation time. The use of hybrid air conditioning systems was found significantly useful for sleeper cabins for prolonged operation time, reducing driver fatigue.