Microwave HVAC system promises EV range boost

Known as e-Thermal bank, the system works as a secondary power source within the vehicle, offloading HVAC (heating, ventilation, and air conditioning) duties from the battery, thereby boosting range. During periods of extreme hot or cold weather, in-car HVAC can reduce range by as much as 40 per cent according to the AAA.  

e-Thermal bank works by pairing a chemical heat pump with microwave energy, delivering heating or cooling to the cabin on demand, with higher energy density than battery packs. Microwave energy dissociates a solid-vapour working pair and also condenses the vapour into liquid. This charging process stores the energy inside the car, within the e-Thermal bank.

The discharge process sees these steps reversed, with the vapour fed into a reactor to generate heat, while a liquid-gas phase change process in an evaporator generates cooling simultaneously. According to the researchers, the thermochemical system has a high-density of 1600Wh/Kg. By contrast, the record density for lithium-ion batteries is around 700Wh/Kg.