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This work presents a comparison of the values of isochoric and isobaric heat capacities in a liquid in the range of parameters from 20°C to 140°C and pressures from 2 MPa to 10 MPa, obtained by two different methods. Under one of the proposed methods isobaric and isochoric heat capacities are obtained within joint thermal (pυT-dependence) and acoustic (speed of sound) measurements, the other method represents heat capacity values are obtained from a unified equation of state presented by the authors earlier based on the results of experimental and computational studies. New density measurements on 7 isotherms in the liquid and supercritical areas of state in the temperature range from 5°C to 141°C and pressure from 1.6 MPa to 10.9 MPa are presented. Estimation of the calculated based on experimental data for the isochoric heat capacity is ± 5%. The discrepancy between the calculated values of the heat capacity by both methods in the entire range of the studied temperatures reaches 30%, which is explained by the lack of experimental data on the heat capacity in the known literature.

Two virtual laboratory works are presented in the developed complex: “Measurement of the heat capacity of air” and “Processes in moist air” performed in the Excel 2010 spreadsheet. The works are devoted to the study of processes in ideal gases, in particular in humid air, and are virtual analogues of physical work, on existing stands in the laboratory of technical thermodynamics of the Department of Theoretical Foundations of Heat Engineering MPEI, corresponding to the bachelor’s program in the disciplines “Thermodynamics” and “Technical Thermodynamics”. The presented material is intended to be included in the educational process in case of repair of existing laboratory stands, as well as for distance learning of students

Представлено варіант вирішення завдання вибору робочого тіла з урахуванням обмежень Монреальського і Кіотського протоколів для теплосилового контуру енергетичних установок на наведених робочих речовинах з можливістю значного підвищення енергоефективності циклу і безпеки експлуатації установок. Для фторуглеродних робочих тіл і SF6 виявлено невідповідність на чотири порядки величини для критерію Lifetime, отриманого за даними IPCC-13, що дає підставу для їх застосування без обмежень, зазначених у Кіотському протоколі. Ключові слова: енергетична установка, робочі тіла енергетичних циклів, стабільність речовин, гексафторид сірки.