Performance Evaluation of a Variable Frequency Heat Pump Air Conditioning System for Electric Bus

Abstract

Abstract This study presents a simulation model of a heat pump air conditioning system with a variable capacity compressor and variable speeds fans for electric bus. An experimental sample has been developed in order to check results from the model. Effects on system performance of such working conditions as compressor speed, evaporator fans speeds and the condenser fans speeds have been simulated by means of developed model. The results show that the three speeds can be adjusted simultaneously according to actual working condition so that the AC system can operate under the optimum state which the control objects want to achieve. It would be a good and simple solution to extend the driving ranges of EVs because of the highest efficiency and the lowest energy consumption of AC system. Keywords: Air conditioning; Heat pump; Electric bus; EER; Variable frequency 1. Introduction During the last several decades, the world energy crisis and environmental pollution have been growing with increasing speed. Therefore, the automotive industry is trying to reduce fossil fuel consumption; they are looking for an alternative energy to fossil fuels for a long time. Vehicles using batteries or fuel cells as a power source have been studied and recommended. Especially, electric vehicle (EV) is a good replacement for conventional vehicle with international combustion engines because of the realization of the true emission”. Air conditioning systems are an essential accessory component of vehicles whose utilization provides comfort to vehicle occupants. However the use of battery packs for cooling and heating can seriously impact the already short driving ranges of EVs. Therefore, for reducing the influence of AC system on driving ranges, maximizing efficiency and performance of AC system is very important for zero emission vehicles.