Producing cold from heat with aluminum carboxylate-based metal-organic frameworks

Worldwide cooling energy demands will increase by four times by 2050. Thermally driven cooling technology is an alternative solution to electric heat pumps in removing hazardous refrigerants and harnessing renewables and waste heat. We highlight the advantages of water-stable microporous aluminum-carboxylate-based metal-organic frameworks, or Al-MOFs, as sorbents in the application of producing cold from heat. Here, we synthesize the Al-MOFs with green and scalable processes, which are prerequisites for exploring various industrial and civil applications. A proof-of-concept full-scale adsorption chiller with different Al-MOFs is built up with optimized configurations derived from various characterization techniques. The tested Al-MOFs achieve thermal efficiency above 0.6 and specific cooling power over 1 kW/kg in typical cooling scenarios. Notably, when solar thermal energy is used as the heat source in an outdoor validation, Al-MOFs are weather-resilient solutions that exhibit a stable energy conversion efficiency under fluctuating operating conditions (ambient temperature and solar irradiation).