Application of Phase Change Materials (PCM) for Reducing Cabin Heat Load

摘要

In regions like Indian Subcontinent, Gulf or Saharan & Sub-Saharan Africa, where the sunshine is abundant almost all year round, air-conditioning is an important aspect of vehicles (passenger cars, buses etc.). Higher heat means higher cooling demand which in turn means bigger AC system. Like other auxiliaries, AC compressor is a parasitic load on the engine. The best way to beat heat and reduce cabin heat load is to stop heat build-up itself. The present paper explores one such means of reducing cabin heat build-up by leveraging latent heat properties of phase change materials and thus improving the air condition performance. With the help of a case study this paper aims at detailing comprehensive effect of phase change material (PCM) and its application on the heat build-up inside the cabin of a vehicle, the air conditioning cooling performance, the time required to achieve comfort temperature, work of compression performed by AC compressor and COP. In the case study described in this paper, AC performance evaluation has been carried out in a climatic chamber were severe ambient conditions (45℃ DBT, 40% RH, 1200W/m~2 solar load) are simulated. A series of trials a are carried out by using a combination of PCMs with a melting point of ～55℃ and ～30℃ and a reflective cover. In the most effective combination of the PCM and reflective cover, average cabin temperature at the end of soaking phase of 1 hour is reduced by as much as 27℃ as compared to baseline. The assumed comfort temperature of 30℃ is achieved just in 14 minutes which is 18 minutes faster compared to the baseline case.