The Ratio And Refrigeration Circle Performance Research Of Substituting Refrigerants Of R22 Based On The Method Of Minimum Gain Of Entropy

This thesis introduces the characteristics of non-azeotropic mixed refrigerants'vapor-liquid phase balance in details and presents the mixed refrigerants'complementary theory, saving energy theory and the slippage identity in the process of heat transfer. From the viewpoint of protecting the environment, this thesis proposes that R290, which possesses the similar thermally physical qualities as R22, has the potential to be one of binary substituting refrigerants. Meanwhile, based on the complementary theory of thermal qualities, R600 has been chosen as the other one.The thesis select CSD state equation to compute the thermodynamic parameters and specifically introduce the source of basic parameters requested in the equation. The slippage identity is extremely complicated and significant part in the mixed refrigerants theory. The current various academic models and methods are suitable for limited types of mixed refrigerants and certain range of temperature. The relatively high precision and simpler format of computing methods and formulas for mixed refrigerants conductivity and viscosity are presented after the comparison.Focusing on the irreversible gain of entropy induced by temperature difference between non-azeotropic refrigerant mixtures and the cooled water, the steady heat transferring model between mixed working fluids and the cooled water has been constructed. Taking the minimum temperature difference as benchmark, an original method to compute the relative gain of entropy in different ratios of the mixtures of R290/R600 has been compiled, and the ratio with minimum gain of entropy has been selected as optimal component ratio.The thesis analyzes and compares the single stage compressing chilling circle performances of R22 with the selected mixed refrigerants in the following facets including COP, q0 , exhaust temperature and input power. The conclusion is that it is possible to replace R22 using mixed refrigerants; a fresh and efficient way has been advanced to select the compositions of substituting refrigerants and confirm the relative ratio in the thesis.