Recent developments in ejector refrigeration technologies

Chen, Xiangjie; Omer, Siddig; Worall, Mark; Riffat, Saffa

doi:10.1016/j.rser.2012.11.028

Cited by 205 publications

(67 citation statements)

References 102 publications

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“…These systems can provide cooling temperature below 0 C and can exploit low-grade thermal energy (i.e. as low as 60 C), producing an acceptable COP (0.4e0.6) (Chen et al, 2013b). In 1987, the Montreal Protocol was ratified and among the banned products, there were several halocarbon compounds widely used in refrigeration applications (i.e., chlorofluorocarbon (CFCs) and hydrochlorofluorocarbon (HCFCs)), thus forcing researchers to turn to natural refrigerants and hydrocarbons.…”

Section: Working Fluids For Ejector Refrigerationmentioning

confidence: 99%

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

Besagni

Mereu

Leo

et al. 2015

International Journal of Refrigeration

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COP Entrainment ratio Ejector refrigeration Ejector efficiencies a b s t r a c tThis paper studies the influence of working fluids over the performance of heat driven ejector refrigeration systems performance by using a lumped parameter model. The model used has been selected after a comparison of different models with a set of experimental data available in the literature. The effect of generator, evaporator and condenser temperature over the entrainment ratio and the COP has been investigated for different working fluids in the typical operating conditions of low grade energy sources. The results show a growth in performance (the entrainment ratio and the COP) with a rise in the generator and evaporator temperature and a decrease in the condenser temperature. The working fluids have a great impact on the ejector performance and each refrigerant has its own range of operating conditions. R134a is found to be suitable for low generator temperature (70e100 C), whereas the hydrocarbons R600 is suitable for medium generator temperatures (100e130 C) and R601 for high generator temperatures (130e180 C). i n t e r n a t i o n a l j o u r n a l o f r e f r i g e r a t i o n 5 8 ( 2 0 1 5 ) 1 5 4 e1 7

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Section: Working Fluids For Ejector Refrigerationmentioning

confidence: 99%

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

Besagni

Mereu

Leo

et al. 2015

International Journal of Refrigeration

View full text Add to dashboard Cite

show abstract

“…But, the refrigeration system using CO 2 has an operating stress that it must be operated with a transcritical cycle mode because of the lower critical temperature of CO 2 , and their coefficient of performance (COP) is lower than that of conventional cycle using CFCs and HCFCs refrigerants due to oversized expansion losses [2]. Therefore, a large amount of efforts such as employing additional ejector [3][4][5] or the expander [6][7][8][9] have been made by researchers to recover the throttling losses in the systems. In recent years, ejectors have been getting more attention due to their noticeable features, such as low cost, no moving parts, low maintenance requirements, simple structure, and high performance improvement potential.…”

Section: Introductionmentioning

confidence: 99%

Thermodynamic analysis of a new dual evaporator CO2 transcritical refrigeration cycle

Abdellaoui¹,

Kairouani²

2017

Archives of Thermodynamics

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In this work, a new dual-evaporator CO2 transcritical refrigeration cycle with two ejectors is proposed. In this new system, we proposed to recover the lost energy of condensation coming off the gas cooler and operate the refrigeration cycle ejector free and enhance the system performance and obtain dual-temperature refrigeration simultaneously. The effects of some key parameters on the thermodynamic performance of the modified cycle are theoretically investigated based on energetic and exergetic analysis. The simulation results for the modified cycle indicate more effective system performance improvement than the single ejector in the CO2 vapor compression cycle using ejector as an expander ranging up to 46%. The exergetic analysis for this system is made. The performance characteristics of the proposed cycle show its promise in dual-evaporator refrigeration system.

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“…Different approaches have been employed in order to improve ejector performance as characterised by the entrainment ratio and the compression ratio [1], [2]. Variable geometry [3], [4], [5], and oscillatory motive pressure [6], [7] , [8] are known methods that can affect ejector performance.…”

Section: Introductionmentioning

confidence: 99%

CFD Study of a Variable Flow Geometry Radial Ejector

Rahimi¹,

Buttsworth²,

Malpress³

2017

Proceedings of the 4th International Conference of Fluid Flow, Heat and Mass Transfer (FFHMT'17)

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-To achieve higher performance from ejectors at some working conditions, implementations of variable geometry might be possible. While axisymmetric ejectors with axial flow paths have limitations that make practical implementation of variable geometry difficult, radial ejector configurations have a flow path that is conducive to changes in nozzle and ejector throat area during operation. The geometric adjustment of the radial ejector could be made by simply changing the separation of the radial ejector duct walls and/or the separation of the nozzle walls in order to optimize performance over a range of different conditions. The effects of such changes on the performance of a radial ejector have been investigated using a Computational Fluid Dynamic (CFD) analysis with ANSYS FLUENT software. Axisymmetric CFD models were generated to assess performance for a primary nozzle throat area of 8.792 mm 2 and for ejector throat separations of 2.2 mm, 2.4 mm and 3.0 mm, corresponding to ejector throat areas of 497, 543 and 678 mm 2 , respectively. The CFD analysis reveals that changes ejector performance can be achieved by changing the ejector duct's separation. An increase of 34% in entrainment ratio can be achieved by increasing the ejector throat separation from 2.2 mm to 3.0 mm at fixed primary and secondary pressures of 160 kPa and 1.8 kPa, respectively. If an increase in the ejector malfunction pressure is needed, it could be achieved by decreasing the ejector duct separation. An overall malfunction pressure increase of 18% can be achieved by decreasing the ejector throat separation from 3.0 mm to 2.2 mm at primary and secondary pressures of 250 and 1.8 kPa, respectively.

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Recent developments in ejector refrigeration technologies

Cited by 205 publications

References 102 publications

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

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

Thermodynamic analysis of a new dual evaporator CO2 transcritical refrigeration cycle

CFD Study of a Variable Flow Geometry Radial Ejector

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