Review of trends in solid sorption refrigeration and heat pumping technology

The history of adsorption cycles and the basic cycle are briefly described. The major refrigerants used are water, methanol, and ammonia. 'Physical' adsorbents include zeolites, active carbons, silica gels, and salts in mesoporous silica or alumina. Means of improving heat and mass transfer in both low (water, methanol) and high (ammonia) pressure systems are discussed. These include the use of conventional adsorbents that have been consolidated and more novel materials and approaches. There are a range of new thermodynamic cycles under development which have the varying goals of either using low temperature driving heat or maximizing the energy efficiency when using high temperature heat. In all machines there is a design compromise to be made between compactness (related to capital cost) and energy efficiency.