Advances in heat pump systems: A review

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

Exergy analysis, parametric analysis and optimization for a novel combined power and ejector refrigeration cycle

In ejector refrigeration systems, the performance of the ejector is critical to the performance, capability, size and cost of the whole system. Construction of mathematical models has been used as an effective method for analyzing the performance of the ejector as well as the whole refrigeration system. These models can also be used to guide system operation, interpret experimental results and assist in system design and optimization. The overall objective of this paper is to provide a review of various researches of the mathematical model on the hydrodynamic and thermodynamic character within the ejector. The paper first briefly describes ejector including fundamental principle, flowing and mixing mechanism and the method of model establishment. Then various models consisting of ideal assumptions, governing equations, auxiliary conditions, solution methods and main results are presented. The models can be classified into two main categories: (i) steady thermodynamic models which can be further subdivided into single-phase flow model and two-phase flow model and (ii) dynamic models which are also subdivided according to the flowing phases considered. It has been shown that the dynamic models have higher prediction precision and give more information compared with the steady thermodynamic models. In addition, the simplified empirical and semi-empirical models based on measured data are briefly discussed. This review is useful for understanding the evolution process and the current status of the mathematical models on ejector and highlighting the key aspects of model improvement such as the mixing mechanism, the capture of the shock wave, etc.

Progress of mathematical modeling on ejectors

A comprehensive review of ejector design, performance, and applications

Performance characteristics of the ejector refrigeration system based on the constant area ejector flow model

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.

Rafet Yapici

Papers

Performance characteristics of the ejector refrigeration system based on the constant area ejector flow model

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

Experimental investigation of performance of vapor ejector refrigeration system using refrigerant R123

Performance of a solar ejector cooling-system in the southern region of Turkey

Experimental study on ejector refrigeration system powered by low grade heat