Vol 105, No 8 (2016)

One of the effective modes of improvement of a refrigeration coefficient of vaporcompression machines (first that operating on a simple vaporcompression cycle) is subcooling of a liquid refrigerant after a condenser by an external source of cooling before refrigerant throttling in a flow control valve. The author derived the expression of minimal work in refrigerating cycles using subcooling on the basis of the first and the second principles of thermodynamics; also the efficiency of application of this method for low (in terms of R134a) and high (in terms of ammonia) specific heat of evaporation is compared in the article. The subcooling efficiency depending on external conditions (condensation, boiling temperatures and initial temperature of an external source of cooling) is estimated qualitatively. The subcooling always increases the thermodynamic efficiency of the vaporcompression cycle; this increase may be of ~25% for refrigerants at low evaporation heat at that.

The trends of Improvement of efficiency of the absorber of the waterammonia absorption refrigerating machine using surfaceactive substances are examined. The method of research based on the works studying the absorption process using surfaceactive substances is sited. The degree of enhancement of the coefficient of heat emission from the solution to the refrigerated wall in the absorber at the presence of surfaceactive substances is defined. Based on the data of the production experiment the values of the concentration of the strong solution for the absorption process in the active apparatus were defined. The results of comparison of characteristics of the absorption refrigerating machine using pure apparatuses and the apparatuses using surfaceactive substances are cited.