New Radiant Heater Structure which Combines Warmth and Safety for EV Range Extension

Abstract

<div class="section abstract"><div class="htmlview paragraph">The use of EVs has accelerated worldwide to reduce CO2 emissions and reduce environmental impact. One of the major issues for EVs is their decrease of electric range during heating in winter. This is because the HVAC (Heating Ventilation and Air Conditioning) system with electric heater or HP (Heat pump) system consumes a lot of energy to warm the occupants. That's why many vehicle OEMs consider not only convection heating system with HVAC, but also other systems such as contact heating devices, seat heaters, or steering wheel heaters. Those devices are more efficient at warming the human body, therefore the heating system can save energy and improve the occupant’s comfort. In this paper, the thighs, knees and shins, which cannot be heated by a seat heater, are heated more efficiently than by convection heating by using a high-temperature radiant heater in which the surface heats up to 100°C or more in 1 minute. It contributes to improving comfort and saving energy in transient periods of low temperature condition. The main feature of this technology is a thin-film heater. Low heat capacity due to the thin structure of heating wires and low heat conduction due to the structure surrounding wires with resin of low heat conduction can suppress the inflow of heat to the occupant from the heater surface when the occupant comes into contact with it. The surface temperature drops rapidly when the occupant is in contact with the heater surface due to this structure and the skin temperature of the occupant does not exceed 52°C. Therefore, the heating performance can be compatible with the safety requirements, and it contributes to energy saving.</div></div>