Effects of geometric parameters and operating conditions on the performance of a high-voltage PTC heater for an electric vehicle

To realize the maximum mileage of an electric vehicle per single charge in winter, improving the positive temperature coefficient (PTC) heater performance and reducing the power consumption of the heating, ventilation, and air-conditioning system is necessary. Therefore, a lightweight heater technology having good thermal performance characteristics and power density is required for the optimal design of PTC heater components. In this study, the geometric parameters of the heater were set for an experiment involving a comparison of the analysis results of the heater models for various radiation fins. The bead array fin heater exhibited an 11.8% higher heating capacity, 2.5% higher efficiency, 7.2% higher pressure drop, and an 11.7% higher power density than the plate fin heater. The bead-emboss fin heater showed 10.3% higher heating capacity, 1.2% higher efficiency, 0.4% higher pressure drop, and 23.7% higher power density than the plate fin heater. Furthermore, the air-side heat transfer and friction characteristics were investigated according to the high-voltage PTC heater operating conditions in an electric vehicle. In the bead-emboss fin heater, the j factor was 8.0% higher and f factor was 39.6% lower on average for 300 < Re < 1700 than in the plate fin heater.