Investigations On Reducing The Car Cabin Temperature Subjected To Solar Load By Incorporating Phase Change Material

Abstract

The main focus of this research is to investigate the feasibility of employing phase change materials towards reducing the interior car cabin air temperature parked in open sunlight. Although the major portion of this research is carried out using Computational Fluid Dynamics (CFD) simulations, few experiments are also carried out for validation. A hatchback car is considered for conducting the experiments and the same have been modelled using CATIA V5 for performing numerical simulations. Two phase change materials namely organic material (OM29) and hydrated salt (HS24) have been identified based upon the conditions of human thermal comfort. The influence of employing these phase change materials and their orientation on reducing the car cabin air temperature have been investigated. Five different orientations namely flat PCM (OM29) partially covering the roof, flat PCM (OM29) covering the roof, 1 curvature of PCM (OM29 and HS24) covering the roof, 2 curvatures of PCM (OM29 and HS24) covering the roof and 3 curvatures of PCM (HS24) covering the roof are considered. For the flat PCM (OM29) partially covering the roof orientation, both experimental and numerical study have been carried out and the deviation in average car cabin air temperature is found to be satisfactory (9.93 %). newlineHowever, the computational time is found to be expensive due to the large car volume and use of conventional two phase simulation for modelling PCM. In order to overcome this difficulty, the assumptions considered for developing the CFD methodology were revisited. Efforts have been brought in, to propose a new methodology called equivalent specific heat using which the conventional two-phase simulation for modelling the PCM can be avoided. In this novel method, an energy storage material (which mimics PCM) is modelled and the behavior of PCM is brought into the simulation as a boundary condition defined in terms of equivalent specific heat between solidus and liquidus temperature. This novel method has been employed for the flat PCM (OM2