ANALYSIS OF THE EFFICIENCY OF THE REFRIGERATION UNIT IN THE HEATING AND COOLING MODE

The article presents a study of a refrigeration unit operating in two modes – heating and cooling. The study is aimed at evaluating the effectiveness of the system for each mode.
In the process of efficiency analysis, heat flows passing through key components of the installation, such as a condenser and an evaporator, were taken into account.
The analytical dependences of the heat load on the evaporator and the compressor power, the refrigeration coefficient and the transformation coefficient relative to the temperature of the coolant at the inlet to the heat exchanger are given, comparative cycles of a heat pump with an intermediate heat exchanger for steady-state cooling and heating modes were constructed, and their nodal points were analyzed.
The results showed differences in characteristics depending on the operating mode of the system, which made it possible to identify optimal conditions for increasing the overall efficiency of the installation.
The balance points for the heating and cooling mode were identified, where the thermal load on the evaporator is equalized with the compressor power.
Analytical dependences of the installation characteristics for both the cooling and heating modes were obtained.
The accuracy of the approximation of all the obtained lines was more than 0,95.
As a result of the conducted research, it was found that the refrigeration system works more efficiently in heating mode, and the optimal temperature of the coolant for cooling and heating modes was 5,5°С и 9°С respectively.

1. Bertinat M.P. Fluids for high temperature heat pumps / M.P. Bertinat // International Journal of Refrigeration. – 1986. – № 9. – Р. 43-50.

2. Alefeld G. Efficiency of compressor heat pumps and refrigerators derived from the second law of thermodynamics / G. Alefeld // International Journal of Refrigeration. – 1987. – № 10. – Р. 331-341.

3. Gomri R. Hakimi, Second law analysis of double effect vapour absorption cooler system / R. Gomri, R. Hakimi // Energy Conversion and Management. – 2008. – № 49. – Р. 3343-3348.

4. Aprhornratana S. Thermodynamic analysis of absorption refrigeration cycles using the second law of thermodynamics method / S. Aprhornratana, I.W. Eames // International Journal of Refrigeration. – 1995. – № 18. – Р. 244-252.

5. Arsalis A. Thermoeconomic modeling and exergy analysis of a decentralized liquefied natural gasfueled combined-cooling–heating-and-power plant / A. Arsalis, A. Alexandrou // Journal of Natural Gas Science and Engineering. – 2014. – № 21. – Р. 198-222.

6. Li Y. Exergy-analysis based comparative study of absorption refrigeration and electric compression refrigeration in CCHP systems / Y. Li, R. Hu // Applied Thermal Engineering. – 2016. – № 93. – Р. 1228-1237.

7. Teplovizionnye obsledovaniya // elektrolab.ru URL: elektrolab.ru/services/teplovizionnyeobsledovaniya (data obrashcheniya: 26.11.2024).

8. Sistemno-strukturnyj analiz ciklov holodil'nyh mashin i teplonasosnyh ustanovok // journals.uran.ua URL: journals.uran.ua/jme/article/view/57508 (data obrashcheniya: 26.11.2024).

9. Lazarenko O.O. Analiz i upravlenie energoeffektivnost'yu absorbcionnyh bromistolitievyh holodil'nyh mashin na osnove ispol'zovaniya eksergicheskogo podhoda i imitacionnogo modelirovaniya / O.O. Lazarenko, L.V. Galimova // Prikaspijskij zhurnal: upravlenie i vysokie tekhnologii. – 2014. – № 25. – S. 70-80.

10. Kara O. Hepbasli Exergetic assessment of direct-expansion solar-assisted heat pump systems: Review and modeling / O. Kara, K. Ulgen // Renewable and Sustainable Energy Reviews. – 2008. – № 12. – Р. 1383-1401.