Theoretical And Experimental Study Of An Air-cooled Type Non-adiabatic Absorption Refrigeration Cycle With Ammonia/Salt Refrigerant Solutions

With the development of global economic society and the sustainable consumption of non-renewable energy resource, the situation of world energy security is getting worse. In the context of energy conservation and emission reduction required by the Chinese government, subjects concerning about high efficient utilization of energy as well as the development and utilization of renewable energy are now attracting interests from all over the world. Utilization of low grade energy especially low grade energy in low temperature range will be of strategic significance in mitigation of energy crisis. It is well know that absorption refrigerators can directly utilize low grade energy. Comparing to the H2O-LiBr and NH3-H2O absorption refrigeration systems, NH3/NaSCN and NH3/LiNO3absorption refrigeration cycles can provide cooling capacity at evaporating temperature of Te<0℃which can not be obtained by the water-LiBr systems.Until present, the key problems in the development process of ammonia/salt absorption refrigeration are respectively the lack of experimental data of thermophysical properties especially the specific entropy of ammonia/salt solution which cause inaccuracies in exergy analysis of the cycle, low cycle coefficient of performance and the lack of optimization method in air-cooled type system, the lack of experimental results. Research work will be carried out concentrating on these problems by the present paper. This paper collects and correlates experimental data provided by other researchers and obtained corresponding correlations for NH3/NaSCN and NH3/LiNO3solution thermophysical properties calculation. In the methodology of specific entropy calculation of the working pair, Debye-Hiickel’s limiting law has been used to obtained activity coefficient of the salt component in NH3/NaSCN or NH3/LiNO3solution with a very low ammonia concentration, this new methodology is theoretical valid, and finally, specific entropies of the ammonia/salt solution in wide temperature and concentration ranges are obtained. Thermodynamic analysis on both single and double effect NH3/NaSCN or NH3/LiNO3air-cooled absorption refrigeration cycle has been carried out, parametric analysis results on system performance especially the variation of absorber outlet solution temperature on cycle performance as well as working parameters of other system components are provided. Exergy analysis of single effect air-cooled type non-adiabatic ammonia/salt absorption cycle has been carried out, in particular, variation of cycle exergetic efficiency as well as exergy destruction rate of different system components with different absorber outlet solution temperatures has been in-depth studied. Based on the theoretical analysis results, this paper designs and builds an experimental bench, with which, experimental study of the system under different working parameters has been carried out. Cycle performances under different working conditions are obtained.The research results of the present paper are not only of important academic value. but also to a great extent help to promote development of refrigeration products with NH3/NaSCN and NH3/LiNO3as working pairs...