there's a lot of path dependence in the way we harness and use energy. we started using animal and water power, which produces mechanical work. then we developed combustion engines to serve all the applications created by animal power. then we developed electrical generators to convert mechanical work to electricity because engines produced mechanical work. then we developed air conditioners that use compressors driven by electric motors. so we're going chemical to mechanical to electrical to mechanical to thermal, instead of just doing adsorption directly with heat energy from the fuel