scholarly journals Thermodynamic performance comparison of series and parallel two-stage evaporation vapor compression refrigeration cycle

2021 ◽  
Vol 7 ◽  
pp. 1616-1626
Author(s):  
Qiulin Wang ◽  
Tailu Li ◽  
Yanan Jia ◽  
Weiming Zhang
Keyword(s):  
Performance Comparison ◽  
Refrigeration Cycle ◽  
Vapor Compression ◽  
Two Stage ◽  
Thermodynamic Performance ◽  
Vapor Compression Refrigeration Cycle ◽  
Vapor Compression Refrigeration

Comparison of Subcooling Effect of Water as a Refrigerant With the Current Refrigerants

2006 ◽  
Author(s):  
Ali Kilicarslan ◽  
Norbert Mu¨ller
Keyword(s):  
Computer Program ◽  
Performance Comparison ◽  
The Other ◽  
Refrigeration Cycle ◽  
Vapor Compression ◽  
Evaporator Temperature ◽  
Vapor Compression Refrigeration Cycle ◽  
Condenser Temperature ◽  
Vapor Compression Refrigeration ◽  
Compressor Efficiency

The performance comparison of water as a refrigerant (R718) with some prevailing refrigerants including R717, R290, R134a, R12, R22, and R152a is presented. A computer program simulating an actual vapor compression refrigeration cycle including subcooling was developed to calculate the coefficient of performances (COPs) for the different refrigerants. Evaporator temperatures above which water yields a better COP over the other refrigerants are investigated for subcooling case. The effect of degree of subcooling on the COPs is elaborated. For most of the refrigerants (R290, R134a, R12, R22, and R152a) the COP increases by around one percent (1%) per one Kelvin (1K) subcooling, while the COP for R718 and R717 increases by around 0.2 % and 0.5 % per one Kelvin (1K) subcooling. At constant evaporator temperature, increasing the degree of subcooling results in decrease of the relative COP gain of R718. R718 gives the highest relative COP increase at constant condenser temperature and polytropic efficiency. The effect of polytropic efficiency on the performance is also investigated. It is observed that the evaporator temperature range at which R718 presents a better COP than other refrigerants increases with increasing values of polytropic compressor efficiency if the degree of subcooling is kept constant.

Optimum Refrigerating Efficiency and Exergy Index of a Two-Stage Refrigeration Cycle

Volume 1 ◽  
2004 ◽  
Author(s):  
J. S. Tiedeman ◽  
S. A. Sherif
Keyword(s):  
Performance Optimization ◽  
Geometric Mean ◽  
Maximum Error ◽  
Second Law ◽  
Refrigeration Cycle ◽  
Vapor Compression ◽  
Two Stage ◽  
Optimization Study ◽  
Vapor Compression Refrigeration Cycle ◽  
Vapor Compression Refrigeration

This paper presents results of an optimization study for a two-stage vapor compression refrigeration cycle based on the refrigerating efficiency and exergy index. Traditional two-stage refrigeration cycle studies have focused on the first law performance, while those studies dealing with the second law have primarily been limited to performance analysis as opposed to performance optimization. Results of this study indicate that the use of the common approximation of the geometric mean to find the optimum interstage pressure leads to nearly optimum results for the refrigerating efficiency, with maximum error in the neighborhood of 5%. However, the error associated with using this approximation to find the optimum exergy index is too large, approaching 15%. Second law optimization revealed that the optimum data curves themselves have maxima for each set of conditions tested. There are a series of conditions that lead to the conclusion that, for a given system, there is an optimum set of conditions that lead to the lowest amount of exergy destruction for that system. Polynomial equations have been fitted to the resultant optimum data for the refrigerating efficiency and exergy index. These equations allow for the reproduction of optimum points based on high- and low-pressure compressor efficiencies and condenser and evaporator pressures.

scholarly journals Parametric analysis of a combined ejector-vapor compression refrigeration cycle

2020 ◽  
Vol 15 (3) ◽  
pp. 398-408
Author(s):  
I Ouelhazi ◽  
Y Ezzaalouni ◽  
L Kairouani
Keyword(s):  
Current Model ◽  
Operating Conditions ◽  
Coefficient Of Performance ◽  
Refrigeration Cycle ◽  
Vapor Compression ◽  
Refrigeration System ◽  
Entrainment Ratio ◽  
Constant Area ◽  
Vapor Compression Refrigeration Cycle ◽  
Vapor Compression Refrigeration

Abstract From the last few years, the use of efficient ejector in refrigeration systems has been paid a lot of attention. In this article a description of a refrigeration system that combines a basic vapor compression refrigeration cycle with an ejector cooling cycle is presented. A one-dimensional mathematical model is developed using the flow governing thermodynamic equations based on a constant area ejector flow model. The model includes effects of friction at the constant-area mixing chamber. The current model is based on the NIST-REFPROP database for refrigerant property calculations. The model has basically been used to determine the effect of the ejector geometry and operating conditions on the performance of the whole refrigeration system. The results show that the proposed model predicts ejector performance, entrainment ratio and the coefficient of performance of the system and their sensitivity to evaporating and generating temperature of the cascade refrigeration cycle. The simulated performance has been then compared with the available experimental data from the literature for validation.

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