The simulation energy efficiency of a refrigeration machine using natural refrigerants (mixtures based on ammonia)

Ammonia (R717) is used as a refrigerant more than 100 years. Ammonia is characterized with zero value of the ozone depletion potential. in spite of it, there are almost no possibilities to use ammonia in small refrigerating machines with hermetic piston compressor. An analysis of the researches shows that all disadvantages of ammonia as a refrigerant can be avoided if ammonia - hydrocarbon mixtures is used. Such mixtures are not thoroughly examined though the existence heteroazeotropes is proven. The aim of this study is development of the effective natural refrigerants for small refrigerating machines and based on the mixtures of NH3 with hydrocarbons as well as definition of their optimum compositions, thermodynemics and phase behavior. The results are as follows: development of the thermodynamics unified equations of state for the refrigerants based on ammonia - hydrocarbon mixtures; obtaining the optimum compositions for ammonia - hydrocarbon refrigerant mixtures; obtaining of the energetic characteristics of small refrigerating machines working on multicomponent natural refrigerants.