Analysis of the Influence of Air Curtain on Reducing the Heat Infiltration and Costs in Urban Electric Buses

In tropical countries, the power demand from the air conditioning system of an electric vehicle can be up to 40 percent of the total power demand of the traction battery. It is therefore essential to investigate methods that improve the efficiency to reduce the capital and operational costs of the vehicle. In public transportation, the frequent opening and closing of doors at bus stops results in a large influx of warm, humid ambient air into the cabin that increases energy consumption. The use of an air curtain is a potential solution that can minimise the infiltration of ambient air into the vehicle. The feasibility of implementation of an air curtain is however dependent on various factors such as the frequency of consecutive bus stops, duration of dwell time at bus stops, efficiency of the air conditioning system and the power consumed by the air curtain device. This paper investigates and compares the reduction of the air conditioning power consumption and the associated battery and energy costs with the use of air curtain in a 6 m mini-bus driving on selected bus routes in Singapore. The use of air curtain in an urban mini-bus is found to be economically feasible as the air conditioning power consumption for the studied routes reduced in the range of 20 ∼ 28%. Subsequently, energy and battery lifecycle costs reduced by 6 ∼ 10% based on the route, the frequency and duration of door openings.