A team of Chinese researchers has designed a new battery concept that can extract thermal energy from low-temperature waste heat sources and reuse it on demand, simply by controlling the pressure.

About 70 percent of the world's primary energy consumption is lost after conversion, mainly in the form of heat, and harvesting and reusing the lost energy is both profitable and eco-friendly.

The team of scientists, led by researchers from the Institute of Metal Research of the Chinese Academy of Sciences, developed a "heat battery" with ammonium thiocyanate that can store the heat directly instead of transferring it to other forms like chemical energy.

They managed to utilize the unique "inverse barocaloric effect", which absorbs heat with pressure while releasing heat with pressure relief. This is the opposite of the typical barocaloric effect.

"A barocaloric thermal battery cycle consists of three steps, namely, thermal charging upon pressurization, storage with pressure and thermal discharging upon depressurization," says Li Bing, the corresponding author of the study published recently in the journal Science Advances.

The pressure-restrained heat-carrying phase can better guarantee stable long-duration storage, according to the study. The heat release that takes place at depressurization is 11 times more than the input mechanical energy, the study notes.

Apart from storing waste heat in thermal power plants, the thermal battery is also expected to have broad applications in other areas, such as solid-state refrigeration, smart grids and house heat management, contributing to China's efforts to peak its carbon dioxide emissions by 2030 and achieve carbon neutrality by 2060, the researchers say.

Xinhua