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Abstract
Solutions of refrigerants in compressor oils are the real working fluids of vapor compression refrigerating systems. However, questions about the effect of admixtures of compressor oil in the refrigerant on the performance of the refrigeration compressor system remain insufficiently studied due to the lack of available information on the caloric properties of the solutions of refrigerant/compressor oil. The results of an experimental study of the isochoric heat capacity in the two-phase region of solutions of dimethyl ether (DME) in triethylene glycol (TEG) are presenttd in the paper. The objects of study have been chosen as a model thermodynamic systems for the studying of the caloric properties of real working fluids of vapor compression refrigeration systems - solutions of refrigerants in compressor oils. Experimental studies of the caloric properties of solutions of DME / TEG and their components were performed by monotonic heating in an adiabatic calorimeter in the temperature range of 243.15 < T < 333.15 К and concentrations of DME 0.241, 0.606 and 0.746 kg/kg. The expanded uncertainty of the obtained experimental data on the isochoric heat capacity in the two-phase region does not exceed 0,75%. Using the obtained experimental information on the isochoric heat capacity in the two-phase region, the values of the specific isochoric and isobaric heat capacities, specific enthalpy and specific entropy at the boiling line were calculated. An analysis of the temperature and concentration dependences of the caloric properties of solutions of dimethyl ether in triethylene glycol was performed. It is shown that TEG admixtures significantly affect the caloric properties of DME / TEG solutions. The obtained data on the caloric properties of solutions of DME / TEG indicate the need to take into account the effect of admixtures of compressor oils on the thermodynamic properties of real working fluids of vapor compression refrigeration systems and the values of the coefficient of performance of the thermodynamic cycle when developing new and modernization of used refrigeration equipment.
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