Research On Dynamic Characteristics For Ammonia-water Solution Desorption And Compression Refrigeration Cycle

With the requirement of energy conservation and environmental protection, ammonia refrigeration has become the research focus in recently years, which promote the development of new ammonia refrigeration system. However the conventional ammonia vapor compression refrigeration system has a lower safety and the COP (coefficient of performance) of conventional ammonia solution absorption refrigeration systems is relatively smaller because of its complicated system and bulky equipment. Our research team proposed a new refrigeration cycle, ammonia-water solution desorption and compression refrigeration cycle (ADAR cycle) which takes desorption and absorption processes instead of evaporation and condensation processes in traditional refrigeration cycle. The performance test of the whole unit has been done on the base of thermodynamic analysis and the key technologies experiments of ADAR Cycle.In this paper, the mainly contents are as follows:Firstly, an off-design analysis model of ADAR is built. The analysis of off-design performance was made under the thermodynamics analysis of ADAR cycle, the influence of matching properties between compressor, low-voltage generator and absorber are discussed to refrigeration cycle, which will serve the purpose of regulation of energy in the ADAR cycle.Secondly, an irreversible ADAR cycle is established on the basis of the finite time thermodynamics analysis, which is closer to practical engineering. Heat transfer losses and internal dissipation are considered. The analysis show the effects of heat transfer losses and internal dissipation on the performance between coefficient of performance and cooling load. The results obtained can provide theoretical instructions for design and optimization of ADAR cycle.Thirdly, the dynamic model of the whole system of ADAR cycle is constructed on the base of steady condition. It has been analyzed that the characteristic of inlet temperature of cooling water and cold water, which are the effects on all components and the whole unit. According to the analysis, the unit operation characteristic has been presented. So that we can get better controls of the unit in the best matching state.Fourthly, many experiments have been done on the complete refrigeration system. The COP of ADAR cycle is higher 0.82 than that of ammonia compression refrigeration cycle under the same conditions. The feasibilities and advantage of ADAR cycle have been shown through the theoretical research and experiments study.