[en] Graphical abstract: This paper experimentally analyzes thermal performance of an air-cooled type single effect absorption refrigeration cycle with ammonia–lithium nitrate and ammonia–sodium thiocyanate solutions as working pairs. The experimental apparatus operated steadily under different working conditions. A set of tests were conducted and the corresponding experimental data including temperatures and pressures of the refrigerant and solution as well as the mass flow rate of the refrigerant was measured and recorded to show the variation of the system performances with different system working parameters. The experimental results of the present study demonstrate the feasibility and capability of ammonia/salt absorption refrigeration cycle for freezing purpose under air cooling conditions. - Highlights: • Ammonia/salt absorption refrigeration cycles are experimentally analyzed. • Both NH_3–LiNO_3 and NH_3–NaSCN systems are analyzed. • System has a stable operation condition under air cooling conditions. • Detail working parameters of the ammonia–salt system are provided. • Refrigeration capacity under low evaporating temperature conditions are obtained. - Abstract: This paper experimentally analyzes thermal performance of an air-cooled type single effect absorption refrigeration cycle with ammonia–lithium nitrate and ammonia–sodium thiocyanate solutions as working pairs. Ammonia/salt system has simple construction, low evaporating temperature (<0 °C) and high working efficiency. Ammonia is one kind of environment-friendly refrigerants. Hence, ammonia/salt absorption refrigeration cycles are considered to be the most possible ones for practical application in small capacity refrigeration units. An experimental apparatus has been designed and built in Wuhan, China, to evaluate the cycle thermal performance of air-cooled type single effect ammonia/salts absorption refrigeration system. The experimental apparatus operates steadily under different working conditions. A set of tests have been conducted and the corresponding experimental data are measured and recorded to show the variation of the system performances with different system working parameters. For the NH_3–LiNO_3 system, the measured lowest evaporation temperature reaches −13.1 °C with corresponding average system COP of 0.15, and the average refrigerating capacity is about 670 W. For the NH_3–NaSCN system, with a measured evaporation temperature of −7.5 °C, the corresponding average COP is 0.20, and the average refrigerating capacity was about 590 W. According to the experimental results, the actual measured COP of NH_3–NaSCN system are in the range of 0.20–0.35, which are a little higher than that of NH_3–LiNO_3 system (actual measured COP ranging from 0.15 to 0.29). Under similar working condition, NH_3–LiNO_3 system can reach a lower evaporation temperature than that of NH_3–NaSCN system. The experimental results of the present study demonstrate the feasibility and capability of ammonia/salt absorption refrigeration cycle for freezing purpose under air cooling conditions. Although the coefficient of performance of the experimental apparatus is below expectation while comparing with the theoretical results, optimization methods are put forward by the present paper for further research.

[en] Graphical abstract: A novel air-cooled non-adiabatic ejection-absorption refrigeration cycle using R290/refrigeration oil has been thermodynamically analyzed. Influences of the ejector and the non-adiabatic absorber applications on the system performance and other system operation parameters have been investigated. The simulation results will be of great help to the miniaturization and practical application of the air-cooled absorption refrigeration system. - Highlights: • A novel air-cooled non-adiabatic ejection-absorption refrigeration cycle is proposed. • Influences of the ejector and the air-cooled non-adiabatic absorber applications on the system performance are investigated. • Variations of system performance and other system operation parameters are investigated. • R290/refrigeration oil mixture used as working pairs is analyzed. - Abstract: This paper thermodynamically analyzes a novel air-cooled non-adiabatic ejection-absorption refrigeration cycle with R290/oil mixture driven by exhaust heat. An ejector located at the upstream of the non-adiabatic absorber is employed to improve the cycle performance. Variations of COP, circulation ratio and component heat load of the system as a function of generating temperature, pressure ratio, absorption temperature, condensing temperature and evaporating temperature have been investigated in this work. The simulation results show that, compared with the conventional absorption refrigeration cycle, this non-adiabatic ejection-absorption refrigeration cycle has higher absorption efficiency, better performance, wider working condition range and lower total heat load and its COP can reach as high as 0.5297. The implementation of the ejector and the non-adiabatic absorber helps to realize the miniaturization and wider application of the absorption refrigeration system. In addition, R290/oil mixture is a kind of highly potential working pairs for absorption refrigeration.