About the authors
| First name, Middle name, Last name, Scientific degree, Scientific rank, Current position. Full and brief name of the organization, The organization address. | Feras Al Gogo, Samara State Technical University, Samara, Russian Federation E-mail: This e-mail address is being protected from spambots. You need JavaScript enabled to view it , ORCID: 0009-0005-6157-2218 Danila V. Zelentsov, candidate of technical sciences, associate professor, Samara State Technical University, Samara, Russian Federation E-mail: This e-mail address is being protected from spambots. You need JavaScript enabled to view it , ORCID: 0000-0001-7124-5847 |
| Title of the article | Exergetic analysis for single-stage and two-stage absorption refrigerating machine |
| Abstract. | The main challenge in absorption refrigerating machines used for cooling in air conditioning systems for large public and industrial buildings is heat loss within their components, which reduces their thermal performance. While the relationship between thermal characteristics and the circuit design of various machine types is well understood, the impact of exergy losses in circuit elements has not been sufficiently studied. The purpose of the work is to provide quantitative data for an informed selection among different types of absorption refrigerating machines by conducting a comparative analysis of their exergetic efficiency. The objectives of the study include analyzing the thermal and exergetic characteristics of both single-stage and two-stage machines (temperature conditions, heat flows, cooling efficiency), as well as calculating total exergy losses, determining the elements of machines in which the greatest amount of exergy is lost, and making comparisons in order to select the optimal scheme based on the criterion of energy efficiency. Results. The results showed that the optimum temperature for the single-stage machine was 85 °C, and its coefficient of performance (COP) of 0.87, and a heat flow of 411.4 kW. In contrast, the two-stage machine at 140C achieved a COP of 1.522, representing a 42.9% improvement, while the heat flow decreased by 36.5% to 261.4 kW. Additionally, the two-stage machine experienced maximum exergy losses in the generator (34.7 kW) and condenser (36.4 kW), whereas the single-stage machine showed in the condenser (42.7 kW) and absorber (14.8 kW). In this case, the percentage increase in total exergy losses in the two-stage and single-stage systems are converging, and the maximum total exergy losses in the single-stage system at a temperature of 100 °C amounted to 88.7 kW, while in the two-stage system it was 56.2 kW at a temperature of 150 C, which indicates a decrease of 36.7% compared to the single-stage system. Conclusions. The results of the study show that a two-stage absorption refrigeration machine demonstrates higher energy efficiency compared to a single-stage one. This is important for the construction industry, as choosing more energy-efficient equipment reduces energy consumption in buildings and optimizes air conditioning and refrigeration systems, as well as promotes the use of renewable energy sources and reduces the carbon footprint of facilities under construction. |
| Keywords. | absorption refrigerating machine, lithium bromide-water solution, coefficient of performance, heat flow, exergy losses |
| For citations: | Al Gogo F., Zelentsov D.V. Exergetic analysis for single-stage and two-stage absorption refrigerating machine // News of KSUAE, 2025, № 2(72), p. 35-45, DOI: 10.48612/NewsKSUAE/72.3, EDN: BDYHRW |
