scholarly journals A Review of Literature on Various Techniques of COP Improvement in Vapor Compression Refrigeration System

2021 ◽  
Vol 9 (11) ◽  
pp. 1753-1759
Author(s):  
Anupam Mishra
Keyword(s):  
Power Consumption ◽  
Heat Dissipation ◽  
Water Mist ◽  
Nano Particles ◽  
Coefficient Of Performance ◽  
Small Scale ◽  
Vapor Compression ◽  
Refrigeration System ◽  
Nano Fluid ◽  
Vapor Compression Refrigeration

Abstract: This review paper is a study on various methods of performance improvement in domestic refrigeration systems, based on the vapor compression refrigeration VCRS cycle. Here air-cooled, water-cooled, fog cooled, evaporatively cooled condensers and nano-fluid lubricant /coolant methods their working and efficiency are reviewed, compared, analyzed and presented. The paper inspects the work done by different researchers for the maximization of heat loss from condenser & compressor and bringing about necessary modifications to reduce the overall power consumption of domestic refrigerators by improving Coefficient of Performance (COP). Numerous works have been done on improving the heat dissipation capacity of condenser but using nano-fluid in lubricant base as refrigerant and in the compressor shell as coolant is a new technology. Nano-fluid increase heat transfer due the high conductivity nano particles. It has been observed that water cooled condensers and compressors with nano-lubricants/coolants give the best performance improvements but they suit better for big or large refrigeration systems like centralized air conditioning systems or cold storage warehousing, whereas air cooled and evaporative condensers are optimal for small scale or low power appliances like domestic refrigerators, water coolers or split air conditioners to reduce overall power consumption by increasing the COP. Keywords: Refrigeration system, COP improvement, Condenser, Water mist, Evaporative cooling, Nano-fluid coolant, VCRS cycle.

An Experimental Investigation on Vapor Compression Refrigeration System Cascaded with Ejector Refrigeration System

2021 ◽  
pp. 2150028
Author(s):  
Vikas Kumar ◽  
Gulshan Sachdeva ◽  
Sandeep Tiwari ◽  
Parinam Anuradha ◽  
Vaibhav Jain
Keyword(s):  
Experimental Investigation ◽  
Thermal Equilibrium ◽  
Operating Conditions ◽  
Coefficient Of Performance ◽  
Vapor Compression ◽  
Refrigeration System ◽  
Compression System ◽  
Vapor Compression System ◽  
Vapor Compression Refrigeration ◽  
Cascaded System

A conventional vapor compression refrigeration system (VCRS) cascaded with a heat-assisted ejector refrigeration system (ERS) has been experimentally analyzed. Cascading allows the VCRS to operate at lower condenser temperatures and thus achieve a higher coefficient of performance. In this cascaded system, the condenser of the vapor compression system does not dissipate its heat directly to the evaporator of the ERS; instead, water circulates between the condenser of VCRS and the evaporator of ERS to exchange the heat. Seven ejectors of different geometries have been used in the ERS; however, all the ejectors could not maintain thermal equilibrium at the desired operating conditions. The compressor of the cascaded VCRS consumed 1.3 times less power than the noncascaded VCRS. Furthermore, the cascaded system provided a maximum 87.74% improvement in COP over the noncascaded system for the same operating conditions. The performance of the system remained constant until the critical condenser pressure of the ERS.

Refrigeration Cooled Computers: Application and Review

2000 ◽  
Author(s):  
R. R. Schmidt ◽  
M. J. Ellsworth ◽  
R. C. Chu ◽  
D. Agonafer
Keyword(s):  
Temperature Stability ◽  
Continuous Operation ◽  
Coefficient Of Performance ◽  
System Level ◽  
Vapor Compression ◽  
Refrigeration System ◽  
Maintenance System ◽  
Vapor Compression Refrigeration ◽  
Computer Processor ◽  
Heat Loads

Abstract This paper outlines and discusses the application conditions pertinent to refrigeration cooling a computer processor at both the module and system level. Amongst the issues that are addressed are total refrigeration heat load (comprised of active and parasitic heat loads), coefficient of performance (COP), continuous operation (reliability, concurrent maintenance), system heat rejection, condensation formation, and temperature stability. The paper will then examine how a vapor compression refrigeration system has been incorporated in IBM’s high end (Gx) servers. Finally, the paper will touch upon some of the additional complexities of operation at very low temperatures (less than −40 °C).

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.

Properties and Performance of Eco-Friendly Hydro-Fluoro-Olefin (HFO) Refrigerant-R1234yf: Part I

2021 ◽  
pp. 2130005
Author(s):  
B. S. Bibin ◽  
Edison Gundabattini
Keyword(s):  
Ozone Depletion ◽  
Past Research ◽  
Cooling Capacity ◽  
Coefficient Of Performance ◽  
General Effect ◽  
Vapor Compression ◽  
Refrigeration System ◽  
Vapor Compression Refrigeration ◽  
Principal Points ◽  
And Performance

The creation of new age refrigerants might be the answer to the issue of an Earth-wide rise in temperature. Hence, while choosing new refrigerants a careful process is required. The general effect of any refrigerant substance on global warming, energy efficiency, ozone depletion, cost-effectiveness, chemical stability, and safety ought to be assessed. This paper sums up the experimental and numerical investigations directed with the globally accepted R1234yf refrigerant. The paper’s principal points are to assess the capability of the hydro-fluoro-olefin (HFO) refrigerant mainly R1234yf utilized in the refrigeration system (vapor compression systems, domestic refrigeration system) and to explore its utilization as an eco-friendly refrigerant. In the vapor compression refrigeration system, the cooling capacity and coefficient of performance of R1234yf are found to be less, 9% and 11%, respectively compared to that of R134a. But the power consumption of the system with R1234yf increased between 1.6% and 6.7% when compared to R134a. This paper likewise assists with recognizing the gap in the past research works and explores the possibilities for additional works.

Experimental evidence concerning the different behavior of energy and exergy performance indicators of refrigeration systems in transient regimes

2016 ◽  
Vol 41 (1) ◽  
Author(s):  
Elena Eugenia Vasilescu ◽  
Michel Feidt ◽  
Rahal Boussehain ◽  
Alexandru Dobrovicescu
Keyword(s):  
Exergy Analysis ◽  
Initial Temperature ◽  
Stationary Regime ◽  
Coefficient Of Performance ◽  
Vapor Compression ◽  
Refrigeration System ◽  
Transient Regimes ◽  
Energy And Exergy ◽  
Vapor Compression Refrigeration ◽  
Exergy Performance

AbstractThis article presents the results obtained from an energy-exergy analysis of a vapor compression refrigeration system during induced transient regimes. Using experimental data, exergy destruction as a function of time under the influence of some factors that perturb the stationary regime, such as deactivation of piston, variation of mass flow rate and initial temperature of cooled fluid, and diminution of the compressor rotation speed, was calculated. Under the perturbation, an antagonistic increase in the coefficient of performance and a decrease in exergy efficiency were noted.

Frictional and Internal Leakage Losses in Rotary-Vane Two-Phase Refrigerating Expanders

2008 ◽  
Author(s):  
A. M. Mahmoud ◽  
S. A. Sherif ◽  
W. E. Lear
Keyword(s):  
Coefficient Of Performance ◽  
Geometrical Parameters ◽  
Vapor Compression ◽  
Refrigeration System ◽  
Component Level ◽  
Two Phase ◽  
Level Model ◽  
Vapor Compression Refrigeration ◽  
Future Work ◽  
Fluid Parameters

Increasing the coefficient of performance of a vapor compression refrigeration system may be realized by utilizing work recovering expansion devices that lower the enthalpy of the refrigerant at the inlet of the evaporator. Depending on the operational and geometrical parameters of the expander, laminar and viscous two-phase leakage flow within the expander may be present. Single-phase leakage models available in the literature must then be modified or re-derived accordingly. A dynamic frictional model for the expander must also be developed for ideal operation (i.e. no internal leakage) and modified to account for internal leakage accordingly. This paper presents a comprehensive component-level model of inherent friction and internal leakage losses in a two-phase circular rotary-vane expander used in a vapor compression refrigeration system. The model establishes the performance of the expander as a function of geometric and fluid parameters. Accurate modeling and prediction of frictional and internal leakage losses is vital to being able to accurately estimate the efficiency, rotational speed, torque and power of/produced by the expander. Directions for future work are also discussed.

scholarly journals Parametric Optimization of a Two Stage Vapor Compression Refrigeration System by Comparative Evolutionary Techniques

2021 ◽  
Vol 287 ◽  
pp. 03002
Author(s):  
Shuhaimi Mahadzir ◽  
Rasel Ahmed
Keyword(s):  
Energy Consumption ◽  
Computation Time ◽  
Vital Role ◽  
Computational Effort ◽  
Coefficient Of Performance ◽  
Vapor Compression ◽  
Refrigeration System ◽  
Total Energy Consumption ◽  
Two Stage ◽  
Vapor Compression Refrigeration

Multistage refrigeration system plays a vital role in industrial refrigeration for the chemical, petrochemical, pharmaceuticals and food industries. Modern chemical industries are complex, and the problems are commonly multi-dimensional, non-linear and time-consuming. This study presents the application of evolutionary computation techniques, namely PSO (particle swarm optimization), GA (Genetic Algorithm) and SA (Simulated Annealing) to solve a design problem of a two-stage vapor compression refrigeration system. Two objectives are evaluated, namely the minimization of total energy consumption and maximization of the coefficient of performance (COP) of the system. The basis of design for the two-stage refrigeration system is built from and validated against data from published literature. The mass flow ratio, evaporator and condenser temperature, parameters for subcooling and desuperheating, and the coefficient of performance for the basis of design show acceptable results. The errors are below 5% against the data from published literature, which are within errors of significant figures in the calculations. In this work, the optimum solutions show a reduction of the required amount of energy consumption by 30.8% and an increase of the COP by nearly 77% with respect to the basis of design. Further improvements are made to the optimization procedures to prevent early convergence and to increase the search efficiency for finding the global optima. The findings by PSO, GA and SA are in agreement, and all evolutionary techniques achieved proper convergence of the two objective functions. It is also found that PSO requires lower computational effort, less computation time and is also easier to implement compared to GA and SA.

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