Compression-assisted adsorption thermal battery based on composite sorbent for heat supply in alpine cold region

Abstract

Adsorption thermal battery (ATB) has drawn burgeoning attention since it could address the problem of heat loss for long-term or seasonal thermal energy storage. However, poor energy storage efficiency of ATB cannot be avoided at low ambient temperature in cold regions. This paper aims to explore the potential of compression-assisted adsorption thermal battery (CATB) at low ambient temperature in winter. Composite adsorbents with expanded natural graphite and carbon coated metal are developed. Heat and mass transfer as well as adsorption characteristics are investigated, which are used to further analyse thermal performance. Results indicate that thermal conductivities of composite manganese chloride and strontium chloride with carbon coated copper (Cu@C) range from 0.59 W·m−1·K−1 to 3.2 W·m−1·K−1, respectively, while permeabilities range at a magnitude of 10−9–10−13 m2. The increment of global conversion rate is up to 17 % through pressurisation process. Besides, energy storage density and power density of CATB with Cu@C increase from 956 kJ·kg−1 to 1336 kJ·kg−1 and from 531 Wh·kg−1 to 742 Wh·kg−1, respectively, which are increased by up to 7.6 % and 13.7 % when compared with those not using Cu@C. It reveals that CATB could be a promising solution to heat supply issues in cold regions.