A study of working fluids for heat driven ejector refrigeration using lumped parameter models

Besagni, Giorgio; Mereu, Riccardo; Leo, Giuseppe Di; Inzoli, Fabio

doi:10.1016/j.ijrefrig.2015.06.015

Cited by 49 publications

(18 citation statements)

References 39 publications

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“…It should be noticed that the above t cc is not the outlet temperature of the diffuser but the saturated temperature which is corresponding to the critical condensing pressure P cc . Besagni et al [26] studied the optimum ejector performance, which is obtained by adjusting area ratio A r to a suitable value in relation to the variations of generating, evaporating and condensing temperature. This is significant for the design of an ERS.…”

Section: Resultsmentioning

confidence: 99%

“…To obtain more accurate prediction performance, the ejector component efficiencies should be determined carefully since they dramatically influence the validity of an ejector model [26] and the values of the efficiencies depend on the ejector geometry, working fluid and operation conditions [8,9]. In this paper, five efficiencies, η p , η s , η m , φ m and η d are introduced in critical point model.…”

Section: Experimental Verificationmentioning

confidence: 99%

See 1 more Smart Citation

Performance Predictions of Dry and Wet Vapors Ejectors Over Entire Operational Range

Chang

et al. 2017

Energies

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Abstract:If a traditional ideal-gas ejector model is used to evaluate the performance of a wet vapor ejector, large deviations from the experimental results will be unavoidable. Moreover, the model usually fails to assess the ejector performance at subcritical mode. In this paper, we proposed a novel model to evaluate the performance of both dry and wet vapors ejectors over the entire operational range at critical or subcritical modes. The model was obtained by integrating the linear characteristic equations of ejector with critical and breakdown points models, which were developed based on the assumptions of constant-pressure mixing and constant-pressure disturbing. In the models, the equations of the two-phase speed of sound and the property of real gas were introduced and ejector component efficiencies were optimized to improve the accuracy of evaluation. It was validated that the proposed model for the entire operational range can achieve a better performance than those existing for R134a, R141b and R245fa. The critical and breakdown points models were further used to investigate the effect of operational parameters on the performance of an ejector refrigeration system (ERS). The theoretical results indicated that decreasing the saturated generating temperature when the actual condensing temperature decreases, and/or increasing the saturated evaporating temperature can improve the performance of ERS significantly. Moreover, superheating the primary flow before it enters the ejector can further improve the performance of an ERS using R134a as a working fluid.

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Section: Resultsmentioning

confidence: 99%

Section: Experimental Verificationmentioning

confidence: 99%

Performance Predictions of Dry and Wet Vapors Ejectors Over Entire Operational Range

Chang

et al. 2017

Energies

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“…A number of theoretical and experimental studies are given in the review papers. Besagni et al [14] investigated working fluids which used differently in models and compared to these models with a set of experimental data available in the literature, they show that the working fluids had a great impact on the ejector performance and each refrigerant had its own range of operating conditions. On the other hand, it should be noted that the ejectors in the mentioned studies operated with only one evaporation temperature, which was known as the single-evaporator refrigeration system.…”

Section: Introductionmentioning

confidence: 99%

Performance improvement potentials of low global warming potential refrigerants for intercity bus air conditioning system

Ünal¹,

Kutlu²,

Erdinç³

2018

THERM SCI

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Original scientific paper https://doi.org/10.2298/TSCI160704084UIn this study, theoretical investigation of two evaporator ejector refrigeration system was carried out based on energy and exergy analysis using R134a and low global warming potential refrigerants (namely R1234yf and R1234ze(E)). In order to perform the analyses, a simulation model was developed and then the influence of different parameters on the COP, COP increase rate and exergy destructions were discussed for each refrigerant. The model was validated with experimental data for R134a and later used to predict the behavior with R1234yf and R1234ze(E). It was found that the highest exergy destruction occurs in the R1234yf system and the increase rate in the COP with respect to the conventional system by using ejector as an expansion device are 15% for R134a, about 17% for R1234yf and about 15% for R1234ze(E), respectively.

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“…Many studies were performed for comparing the performance of working fluids in ERCs [9,10]. Also, refrigerant mixtures were used for ERC by Yan et al [11].…”

mentioning

confidence: 99%

A Parametric Analysis of an Ejector Refrigeration Cycle Activated by Renewable Energy

Saleh¹,

Tjprc²

2019

IJMPERD

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The refrigeration and cooling systems activated by waste heat and renewable energy sources can achieve high energy efficiency. In this paper, a performance investigation and working fluid choice for an ejector refrigeration cycle (ERC) activated by renewable energy source are conducted. In the ejector mathematical model, the mixing process through the ejector constant-area section is supposed to be constant-pressure process. The performance of some selected hydrocarbons, hydrofluoroolefins, hydrofluoroethers, and hydrofluorocarbons refrigerants in the ERC is examined and compared. The behaviour of the ejector is represented by the ejector area ratio (EAR) and entrainment ratio (), whereas the cycle performance is represented by the coefficient of performance (COP). The impacts of some selected operating parameters as the condenser, evaporator, and generator temperatures on the ejector behaviour and cycle performances are also examined. The results show that the best ejector behaviour and cycle performance are achieved with the highest critical temperature dry refrigerant, i.e. cyclopentane under all examined operating conditions. From energy efficiency and environmental issues viewpoints, cyclopentane can be considered the most appropriate refrigerant amongst all examined working fluids. However, additional precautions should be taken against its flammability. The highest COP value, the corresponding ω, and the needed EAR using cyclopentane are 0.81, 1.03, and 17.3, respectively with a condenser temperature of 25 ºC and the typical values for the remaining operating parameters.

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A study of working fluids for heat driven ejector refrigeration using lumped parameter models

Cited by 49 publications

References 39 publications

Performance Predictions of Dry and Wet Vapors Ejectors Over Entire Operational Range

Performance Predictions of Dry and Wet Vapors Ejectors Over Entire Operational Range

Performance improvement potentials of low global warming potential refrigerants for intercity bus air conditioning system

A Parametric Analysis of an Ejector Refrigeration Cycle Activated by Renewable Energy

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