Experimental And Theoretical Study On Chemisorption Refrigeration

Adsorption refrigeration is a kind of environmentally friendly green refrigeration technology. Its major superiority is the capability of using low-grade thermal energy and environmental protection, so it has been generally regarded as one of the primary technologies for alternation to CFCs conventional compression refrigeration systems in the 21st century. Selection of adsorbent-adsorbate working pairs for adsorption systems is an important aspect. The chemisorption pairs using inorganic salts as adsorbent and ammonia as adsorbate have a series of advantages, such as the large refrigeration capacity per unit weight of adsorbent and the appropriate operation condition, etc., and give vastly developing prospects.Detailed theoretical and experimental studies on the performances of four alkaline-earth metal chlorides, MgCl₂, CaCl₂, SrCl₂ and BaCl₂, adsorbing to ammonia have been carried out in the thesis. The results show that all of above compounds can absorb ammonia, but only the CaCl₂-NH₃ and SrCl₂-NH₃ pairs have commercially developing value. The adsorption isotherm equations of these two pairs are fit by computer. In the experimental range, the maximum ammonia adsorption amounts, 6.4 mol / mol for CaCl₂ and 8.1 mol / mol for SrCl₂, are obtained. The refrigeration performances and the engineering characteristics of the CaCl₂-NH₃ and SrCl₂-NH₃ pairs are also good. A novel ideal that introduce the theory of adsorption potential energy to explain the "adsorption platform" appeared in the adsorption isotherms is presented in this thesis. From the energy point of view, the effect of temperature and pressure on the movement of gas and solid molecules, elastic collisions, inelastic collisions and trapping and physisorption, chemisorption and desorption is analyzed. The result is that temperature is the process control factor. The theoretical analysis and experimental results give a well agreement.The basic performances of the CaCl₂-NH₃ and SrCl₂-NH₃ pairs chemisorption refrigeration and the influenced factors have been investigated experimentally and theoretically. In the same operation conditions, the refrigeration capacity per unit weight of adsorbent of CaCl₂-NH₃ and SrCl₂-NH₃ pairs is far higher than that of activated carbon-methanol pair. For example, in the condition of 100℃heat source...