Enhancing COP of electric vehicle cooling systems using adsorption heat pumps

Abstract

This study includes an adsorption refrigeration system as a secondary cycle to an electric bus's current cooling system. The objective is to increase the COP of the cooling system of the Electric Bus. By increasing the COP, the bus can have a longer range, and the state of health of the batteries can be improved. An adsorption chiller (AdC) is considered, and the waste of the synchronous motor of the electric bus is used as an input energy of the AdC. The novel pair is proposed as silica gel RD/ethanol. This pair gives the flexibility to use the low-temperature heat source of the motor to generate an extra cooling effect. The silica gel/ethanol AdC cooling capacity is optimized by using the cooling generated by the AdC, which does not use any electricity from the bus. The Matlab/Simulink codes of the motor and the adsorption chiller are combined. For different Vdc and rpm conditions, the calculated coolant temperature of the motor is found and used as an input temperature value of the desorption process. Due to the extra cooling capacity caused by subcooling, the COP values of the existing cooling system of the electric bus are achieved to increase to around 9 %.