Thermochemical energy storage for cabin heating in battery powered electric vehicles

Abstract

The potential of thermochemical adsorption heat storage technology for battery electric vehicle (EV) cabin heating was explored in this study. A novel modular reactor with multiple adsorption units was designed with working pair SrCl2-NH3. Numerical models of the proposed system were built, and the system was sized to meet the heating requirement for ambient temperatures ranging from −5–10 °C for 1 ∼ 2 h. The simulation results showed the system can satisfy the required supply air temperature by initially activating 6 adsorption units and activating new units once detecting lower air temperature than required. It was found that the final global conversion of adsorption reaction was 0.62–0.67, indicating a relatively stable system performance over ambient temperatures. To supply a heating power of 1.3 kW for 1 h at an ambient temperature of 5 °C, the designed storage system had an adsorbent mass of 16.37 kg in 12 adsorption units. More adsorption units were needed for lower ambient temperatures, such as 23 adsorption units needed to supply a heating power of 2.4 kW at −5 °C ambient condition. It was found that the overall system energy density was 73.8 kWh/m3, whereas the material energy density was 169.4 kWh/m3. This work also demonstrates the importance of considering adsorption dynamics when assessing the performance of an adsorption system and demonstrates the benefits of a modularly designed adsorption reactor for cabin heating. Show more