Preliminary experimental results on the R134a refrigeration system using a two-phase ejector as an expander

Ersoy, H. Kursad; Sağ, Nagihan Bilir

doi:10.1016/j.ijrefrig.2014.04.006

Cited by 69 publications

(13 citation statements)

References 17 publications

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“…The maximum COP and the second law efficiency are approximately 7% and 5% higher than those of the conventional cycle. Ersoy and Bilir Sag [187] tested a R124a EERS and, depending on the operating condition, the COP was 6.2-14.5% higher than that of the conventional system. Bilir Sag et al [182] (experimental study using R134a) reported an increase of COP by 7.34-12.87% and an increase of the exergy efficiency of 6.6-11.24% compared to a conventional system.…”

Section: Ejector Expansion Refrigeration System (Eers)mentioning

confidence: 98%

Ejector refrigeration: A comprehensive review

Besagni

Mereu

Inzoli

2016

Renewable and Sustainable Energy Reviews

405

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a b s t r a c tThe 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.

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Section: Ejector Expansion Refrigeration System (Eers)mentioning

confidence: 98%

Ejector refrigeration: A comprehensive review

Besagni

Mereu

Inzoli

2016

Renewable and Sustainable Energy Reviews

405

View full text Add to dashboard Cite

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“…Another comparison for R1234yf with Li et al [14] shows that for component efficiency η m = 95% (others are same), the deviation maximum COP (5.979 in present study and 5.94 in previous study [14]) is about 1%. The code has been also validated with experimental data for R134a [21]. For the condenser temperature at 53.28 • C, and evaporator temperature at 8.67 • C with 12 • C superheat, and 79% compressor isentropic efficiency (calculated based on test data), the entrainment ratio (0.64 experimental and 0.671 predicted) and area ratio (5.35 experimental and 5.93 predicted) are deviated by 4.7% and 9.8%, respectively.…”

Section: Resultsmentioning

confidence: 99%

Performance characteristics of low global warming potential R134a alternative refrigerants in ejector-expansion refrigeration system

Mishra¹,

Sarkar²

2016

Archives of Thermodynamics

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Performance assessment of ejector-expansion vapor compression refrigeration system with eco-friendly R134a alternative refrigerants (R152a, R1234yf, R600a, R600, R290, R161, R32, and propylene) is presented for air-conditioning application. Ejector has been modeled by considering experimental data based correlations of component efficiencies to take care of all irreversibilities. Ejector area ratio has been optimized based on maximum coefficient of performance (COP) for typical air-conditioner operating temperatures. Selected refrigerants have been compared based on area ratio, pressure lift ratio, entrainment ratio, COP, COP improvement and volumetric cooling capacity. Effects of normal boiling point and critical point on the performances have been studied as well. Using ejector as an expansion device, maximum improvement in COP is noted in R1234yf (10.1%), which reduces the COP deviation with R134a (4.5% less in basic cycle and 2.5% less in ejector cycle). Hence, R1234yf seems to be best alternative for ejector expansion system due to its mild flammability and comparable volumetric capacity and cooling COP. refrigerant R161 is superior to R134a in terms of both COP and volumetric cooling capacity, although may be restricted for low capacity application due to its flammability. Keywords

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“…Concerning two-phase operation, comparisons were made regarding the choked mass flow through a convergent divergent nozzle and the effect of the primary inlet saturation on the entrainment ratio. Figure 5 compares the predicted entrainment ratio values against experimental data from different studies [8,10,24,[34][35][36] with varying dimensions, working gases and operating conditions. As a first step, friction and mixing losses are neglected here such that:…”

Section: Validation Of the Thermodynamic Modelmentioning

confidence: 99%

Thermodynamic Modelling of Supersonic Gas Ejector with Droplets

Croquer

Poncet

Aidoun

2017

Entropy

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This study presents a thermodynamic model for determining the entrainment ratio and double choke limiting pressure of supersonic ejectors within the context of heat driven refrigeration cycles, with and without droplet injection, at the constant area section of the device. Input data include the inlet operating conditions and key geometry parameters (primary throat, mixing section and diffuser outlet diameter), whereas output information includes the ejector entrainment ratio, maximum double choke compression ratio, ejector efficiency, exergy efficiency and exergy destruction index. In single-phase operation, the ejector entrainment ratio and double choke limiting pressure are determined with a mean accuracy of 18% and 2.5%, respectively. In two-phase operation, the choked mass flow rate across convergent-divergent nozzles is estimated with a deviation of 10%. An analysis on the effect of droplet injection confirms the hypothesis that droplet injection reduces by 8% the pressure and Mach number jumps associated with shock waves occuring at the end of the constant area section. Nonetheless, other factors such as the mixing of the droplets with the main flow are introduced, resulting in an overall reduction by 11% of the ejector efficiency and by 15% of the exergy efficiency.

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Preliminary experimental results on the R134a refrigeration system using a two-phase ejector as an expander

Cited by 69 publications

References 17 publications

Ejector refrigeration: A comprehensive review

Ejector refrigeration: A comprehensive review

Performance characteristics of low global warming potential R134a alternative refrigerants in ejector-expansion refrigeration system

Thermodynamic Modelling of Supersonic Gas Ejector with Droplets

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