Thermal Comfort Optimization in an Electric Vehicle

Abstract

In automobiles, the demand for HVAC has been rising for decades and the key variables that affect the thermal comfort in a car were identified as air velocity, temperature, radiant temperature, and relative humidity. Thermal comfort estimation in a vehicle depends on the transient behavior of the cabin space and boundaries. The predicted mean vote (PMV) and predicted percentage of dissatisfied (PPD) are the available methods to describe and optimize thermal comfort in cabin space. In this paper, the cabin thermal comfort of a minivan was analyzed for reduction of energy consumption with the help of experimental and numerical simulation. Using CFD simulation and validation with experimental data, the flow dynamics inside a vehicle cabin is evaluated based on air velocity, temperature, and comfort indices. With some error for the extreme planes, a strong agreement was reached between the experimental values and the CFD model. With the reduction in the air velocity from 2.3 m/s to 1.3 m/s, the average power required to run the blower can be reduced by 43%, providing an advantage of reducing the capacity of the compressor. The higher PPD values were observed on the walls of the cabin and at the outlet of the AC vents.