Numerical study of the effects of injection-port design on the heating performance of an R134a heat pump with vapor injection used in electric vehicles

•A simulation model for an EV heat pump with vapor injection is developed and validated.•Geometries of the injection port are analyzed according to angle of the injection port.•Design of the injection port is determined to optimize COP and isentropic efficiency.•Performance of dual-injection ports is compared to that of the non-injection heat pump.