HVAC System Boosts BEV Range 70%, College Claims

Researchers at a U.K. university claim they can extend the range of battery-electric vehicles by a whopping 70% using the cars’ air-conditioning system powered by microwaves.

The team from the University of Birmingham, in the Midlands of England, are developing an energy storage system to boost BEV driving range during hot or cold weather when the vehicle’s climate control system is consuming enough electric energy to cut the working range by up to 40%.   

Invented by Birmingham energy expert Yongliang Li during research into technologies for a zero-carbon future, the process couples a chemical heat pump with microwave energy to produces heating or cooling on demand and at much higher energy density than from the vehicle’s battery pack. 

Dubbed the e-Thermal bank, the system creates a secondary energy source for BEVs. It is “charged” when the vehicle gets charged by using microwave energy to dissociate a solid-vapor working pair and also condense the vapor into liquid.  This charging process stores the microwave energy inside the car, in the e-Thermal bank.

Then, during discharging, the process is reversed by feeding the vapor into a reactor to generate heat through an exothermic reaction, while a liquid-gas phase change process in an evaporator generates cooling simultaneously.

Claimed additional benefits of the system include:

The university’s commercial wing, the University of Birmingham Enterprise, has filed a patent application covering the e-Thermal bank system and method for storing energy and is now looking for commercial partners to assist licensing collaboration or co-development.

Yongliang Li, says: “Heating and cooling the EV cabin requires considerable energy and is the most significant contributor to EV range reduction. We aimed to offload these thermal management tasks to a microwave-driven process. Microwave is a fast-heating method, because microwaves penetrate uniformly through materials and so deliver energy evenly into the body of the material. The energy cost can be minimized by coupling with a smart meter to charge the system when energy is cheap and the stored energy can then be used at any time. We predict that by replacing conventional HVAC and possibly a small portion of the battery pack, e-Thermal banks would provide efficient cabin temperature control and a range extension of up to 70%, at a lower cost than increasing battery capacity.”