Simulation of vehicle cooling loads at different orientations

Abstract

This paper presents a numerical simulation of the effect of vehicle orientation on the hourly vehicle cooling load profile. This profile enables prediction of a maximum cooling load and hence maximum cooling capacity to be supplied for equipment selection. The correlations and equations proposed by ASHRAE and previous researchers and compressed Singapore weather data from the open literature were used. Four vehicle orientations: North, East, South, and West were considered for a 1.6L Proton Wira Aeroback passenger car. The steady-state heat balance concept was adopted for the cooling load model. A validation exercise indicates that the simulation results are within 6% of published results. In this study, the cooling load profile predicts a maximum load between 12.00 noon and 1.00 pm for all typical days due to high values of solar radiation intensity and outdoor air dry bulb temperature compared to other hours. The highest cooling load occurs when the front wind screen is facing East in March/April at 2.71 kW. Thus, with a 5% safety factor, the highest cooling load is estimated at 2.85 kW. When the cooling capacity is estimated at 10% higher than this maximum cooling load, the proposed design evaporator coil cooling capacity is then estimated at 3.13 kW. This cooling load/capacity provides a basis for new vehicle air-conditioning system development, especially for future full electric vehicles.