Cooling and heating accounts for about 50% of the global terminal energy consumption, which is expected to maintain rapid growth in the next decade. At present, most of the heat energy supply comes from fossil fuels, which contributes a lot of carbon dioxide emissions. Therefore, under the urgent demand of double carbon target, the development of low-carbon cooling and heating technology is of great significance. Different from electric driven refrigeration and heating solutions, adsorption refrigeration / heat pump can be driven by low-grade heat energy such as solar energy, geothermal energy and low-temperature waste heat. It is a potential low-carbon cooling and heating technology, and the development of efficient and stable adsorption materials is the decisive factor for the application of adsorption refrigeration / heat pump.
Aiming at the problems of poor adsorption performance of traditional silica gel and activated carbon, high cost of emerging metal organic framework (MOFs) materials and difficulty in large-scale production, the heat and mass transfer center of Institute of Engineering Thermophysics, Chinese Academy of Sciences developed SFO aluminum phosphate sieve material with excellent performance and industrialization potential. Detailed test and characterization analysis show that SFO type aluminum phosphate has a sheet shape with a thickness of 20-120 nm and excellent hydrothermal stability. It still maintains its crystallinity, skeleton structure and micropore rate after soaking in boiling water for 24 hours. S-shaped water adsorption isotherm shows that it has suitable hydrophilicity and very low adsorption enthalpy. In addition, the material shows excellent refrigeration performance coefficient COPC = 0.85 at the ultra-low driving temperature of 63 ° C, which is the highest value reported at home and abroad. Under the condition of heat pump, the performance coefficient of the material can reach coph = 1.75 at the driving temperature of 82 ° C. SFO aluminum phosphate also shows fast adsorption and desorption kinetic performance. Under the working conditions of 5 ° C evaporation temperature and 65 ° C desorption temperature, the refrigeration capacity per unit mass can reach scp80% = 1.1 kW kg-1, which is higher than commercial adsorbents and existing MOFs, and the cost of raw materials is lower.
Relevant research results are published in nature communications under the title of ultra low temperature driven water based absorption rectification enabled by low cost zeolitelike sprouts aluminum phosphates. The research work was supported by the scientific researchers of Shanghai Jiaotong University and supported by the national key natural science foundation and the national key R & D plan.