The increasing need for thermal comfort has led to a rapid increase in the use of cooling systems and, consequently, electricity demand for air-conditioning systems in buildings. Heat-driven ejector refrigeration systems appear to be a promising alternative to the traditional compressor-based refrigeration technologies for energy consumption reduction. This paper presents a comprehensive literature review on ejector refrigeration systems and working fluids. It deeply analyzes ejector technology and behavior, refrigerant properties and their influence over ejector performance and all of the ejector refrigeration technologies, with a focus on past, present and future trends. The review is structured in four parts. In the first part, ejector technology is described. In the second part, a detailed description of the refrigerant properties and their influence over ejector performance is presented. In the third part, a review focused on the main jet refrigeration cycles is proposed, and the ejector refrigeration systems are reported and categorized. Finally, an overview over all ejector technologies, the relationship among the working fluids and the ejector performance, with a focus on past, present and future trends, is presented.

https://re.public.polimi.it/bitstream/11311/984261/1/2016_RSER_BesagniMereuInzoli.pdf

Ejector refrigeration: A comprehensive review

Previous reviews on ejectors for expansion work recovery have provided detailed discussions of operating characteristics and control of ejector cycles, zero-dimensional ejector modeling, ejector geometry effects, and alternate ejector cycles. However, important advances in the field of ejector technology have occurred since previous reviews were written. Several focuses of recent ejector research are the development of multi-dimensional CFD ejector models, investigation of alternate ejector cycles and uses of the work recovered by the ejector, implementation of effective control strategies for ejector cycles, and application of ejectors in real systems. The objective of this paper is to present a review of developments in the use of ejectors for expansion work recovery in vapor-compression systems focusing on the past several years. Although the first commercial applications are being introduced to the market, it is suggested that future works continue in these areas in order to make ejectors more suitable for additional applications.

Review of recent developments in advanced ejector technology

A comprehensive review of ejector design, performance, and applications

This paper aims at providing a literature review on the recent development in ejectors, applications of ejector refrigeration systems and system performance enhancement. The paper presents useful guidelines regarding background and operating principles of ejector. A number of studies are reported and categorized in several topics including, refrigerant selections, mathematical modelling and numerical simulation of ejector system, geometric optimizations, operating conditions optimizations and combinations with other refrigeration systems. Most of the works that have been carried out recently are still limited to computer modelling, more experimental and large-scale work are needed in order to provide better understanding for the real industrial application.

Recent developments in ejector refrigeration technologies

This paper presents a useful knowledge of ejector working principles and the versatility and diversity of its applications in refrigeration technologies. Various ejector refrigeration systems are described with the associated studies, and categorized as conventional ejector refrigeration system, advanced ejector refrigeration systems, combined refrigeration systems and ejector enhanced vapor compression systems. This paper also presents the important elements that affect the optimum performance of the ejector system, and the results of studies that have generally confirmed their energy saving, great potential for large refrigerating temperature scales and performance enhancement.

A review on versatile ejector applications in refrigeration systems

The performance of the ejector refrigeration system using ejectors with cylindrical mixing chamber is studied at operating conditions with choking in the mixing chamber. The condenser pressure is chosen so that the secondary flow choking can occur even in the ejector with the smallest area ratio. In the present study, the performance of the constructed system is determined by using six configurations of ejector and R-123 as working fluid in the system. The study is performed over a range of the ejector area ratio from 6.5 to 11.5 at the compression ratio 2.47. In the studied range, the experimental coefficient of performance of the system rises from 0.29 to 0.41, as the optimum generator temperature increases from 83 to 103 °C. Similar results were also found in the parametric study when the efficiencies of the nozzle and diffuser are taken as 0.90.

Experimental determination of the optimum performance of ejector refrigeration system depending on ejector area ratio

Energetic and exergetic comparison of basic and ejector expander refrigeration systems operating under the same external conditions and cooling capacities

Aluminum-magnesium (Al-Mg) alloys have been widely used in diverse applications ranging from automotive bodies to food processing industries because of their excellent high-strength-to-weight ratio, corrosion resistance, and recyclability potential. The formability of these alloys is decreased at room temperature (RT) and is related with the strain-rate sensitivity. This study presents the effect of strain-rate sensitivity on formability of AA 5754-O alloy sheet at a test temperature range of −60 to 250 °C by duplicate tensile test at different strain rates. The test results indicated that the formability change with positive or negative strain-rate sensitivity values. It was observed that the strain-rate sensitivity values increased at negative temperatures with respect to RT. The best formability condition for this alloy in the test ranges was observed at 250 °C and 0.0016 s−1.

Hüseyin Selçuk Halkaci

Papers

Experimental determination of the optimum performance of ejector refrigeration system depending on ejector area ratio

Energetic and exergetic comparison of basic and ejector expander refrigeration systems operating under the same external conditions and cooling capacities

The Effect of Strain-Rate Sensitivity on Formability of AA 5754-O at Cold and Warm Temperatures

Enhancing formability in hydromechanical deep drawing process adding a shallow drawbead to the blank holder

Evaluation of form error at semi-spherical tools by use of image processing