Performance improvement of the vapour compression refrigeration cycle by a two-phase constant area ejector

2009 ◽  
Vol 33 (5) ◽  
pp. 469-480 ◽  
Author(s):  
Nagihan Bilir ◽  
H. Kursad Ersoy
Keyword(s):  
Performance Improvement ◽  
Refrigeration Cycle ◽  
Two Phase ◽  
Constant Area ◽  
Phase Constant ◽  
Vapour Compression

scholarly journals Preliminary Design of the Two-Phase Ejector under Constant Area Mixing Assumption for 5 kW Experimental System

2019 ◽  
Vol 103 ◽  
pp. 01002
Author(s):  
Ayşe Uğurcan Atmaca ◽  
Aytunç Erek ◽  
Orhan Ekren
Keyword(s):  
Experimental System ◽  
Cooling Capacity ◽  
Cycle Performance ◽  
Geometrical Parameters ◽  
Refrigeration Cycle ◽  
Preliminary Design ◽  
Nozzle Outlet ◽  
Two Phase ◽  
Operation Conditions ◽  
Constant Area

Ejector expansion refrigeration cycle is the modification of the vapour compression refrigeration cycle with the implementation of a two-phase ejector and a vapour-liquid separator to improve the cycle performance. In this study, main geometrical parameters of an ejector, i.e. diameters of the motive nozzle throat, motive nozzle outlet, suction nozzle outlet, and constant area mixing section are calculated in order to provide the preliminary design aspects at various operation conditions. The thermodynamic model of the ejector is established with reference to constant-area mixing assumption. The equations are solved in Matlab®. The environmentally-friendly refrigerants, R1234yf and R1234ze(E) from the hydrofluoroolefins (HFOs) and R134a which is about to be phased out by the F-gas Regulation are used in the analyses. When compared to the previous literature findings, the current research aims to compare the dimensions of a two-phase ejector to be used in an experimental system having 5 kW cooling capacity for these three refrigerants.

scholarly journals Performance Analysis of Natural-Refrigerants-Based Vortex Tube Expansion Refrigeration Cycles

2013 ◽  
Vol 06 (2) ◽  
Keyword(s):  
Performance Improvement ◽  
Vortex Tube ◽  
Operating Temperature ◽  
Operating Conditions ◽  
Design Parameters ◽  
Refrigeration Cycle ◽  
Expansion Valve ◽  
Tube Expansion ◽  
Vapour Compression ◽  
Cycle Temperature

The energetic analyses and comparison of three natural refrigerants, ammonia, propane and isobutane based vapour compression refrigeration cycles are presented in this article using a vortex tube as an expansion device. A simple thermodynamic model has been used for analyses of two vortex tube expansion refrigeration cycle layouts based on the Maurer model (1999) and the Keller model (1997). Effects of various operating and design parameters of the COP improvement using vortex tube instead of expansion valve are presented. Results show that the COP improvement over basic expansion cycle increases with increase in cycle temperature lift for both cycle layouts. The COP improvement of CYC1 can be realized for certain operating temperature combinations. Effects of design parameters on the performance improvement are negligible. Study shows that the COP improvement using vortex tube as an expansion device are dependent on the refrigerant varieties, operating conditions as well as cycle configurations. Using the vortex tube as an expansion device, isobutane yields a maximum COP improvement of 12.2% for CYC2 followed by propane (11.5% for CYC2), whereas ammonia yields negligible improvement for studies ranges.

scholarly journals Performance improvement of double-tube gas cooler in CO2 refrigeration system using nanofluids

2015 ◽  
Vol 19 (1) ◽  
pp. 109-118 ◽  
Author(s):  
Jahar Sarkar
Keyword(s):  
Performance Improvement ◽  
Volume Fraction ◽  
Particle Volume Fraction ◽  
Cooling Capacity ◽  
Inlet Temperature ◽  
Refrigeration Cycle ◽  
Particle Volume ◽  
Transcritical Carbon Dioxide ◽  
The Given ◽  
Theoretical Analyses

The theoretical analyses of the double-tube gas cooler in transcritical carbon dioxide refrigeration cycle have been performed to study the performance improvement of gas cooler as well as CO2 cycle using Al2O3, TiO2, CuO and Cu nanofluids as coolants. Effects of various operating parameters (nanofluid inlet temperature and mass flow rate, CO2 pressure and particle volume fraction) are studied as well. Use of nanofluid as coolant in double-tube gas cooler of CO2 cycle improves the gas cooler effectiveness, cooling capacity and COP without penalty of pumping power. The CO2 cycle yields best performance using Al2O3-H2O as a coolant in double-tube gas cooler followed by TiO2-H2O, CuO-H2O and Cu-H2O. The maximum cooling COP improvement of transcritical CO2 cycle for Al2O3-H2O is 25.4%, whereas that for TiO2-H2O is 23.8%, for CuO-H2O is 20.2% and for Cu-H2O is 16.2% for the given ranges of study. Study shows that the nanofluid may effectively use as coolant in double-tube gas cooler to improve the performance of transcritical CO2 refrigeration cycle.

Supersonic two-phase flow of CO2 through converging–diverging nozzles for the ejector refrigeration cycle

2009 ◽  
Vol 32 (6) ◽  
pp. 1195-1202 ◽  
Author(s):  
Masafumi Nakagawa ◽  
Menandro Serrano Berana ◽  
Akinori Kishine
Keyword(s):  
Two Phase Flow ◽  
Refrigeration Cycle ◽  
Phase Flow ◽  
Two Phase

scholarly journals Experimental study on the behavior of the two phase flow shock waves occurring in the ejector refrigeration cycle

2016 ◽  
Vol 3 (6) ◽  
pp. 16-00255-16-00255 ◽  
Author(s):  
Haruyuki NISHIJIMA ◽  
Kyohei TSUCHII ◽  
Masafumi NAKAGAWA
Keyword(s):  
Experimental Study ◽  
Shock Waves ◽  
Two Phase Flow ◽  
Refrigeration Cycle ◽  
Phase Flow ◽  
Two Phase

A Remote Area Power Supply Using Wind Power and Cold Thermal Storage

2002 ◽  
Author(s):  
Kenneth C. Brown
Keyword(s):  
Energy Source ◽  
Power Supply ◽  
Rankine Cycle ◽  
Thermal Storage ◽  
Primary Objective ◽  
Remote Area ◽  
Working Fluid ◽  
Refrigeration Cycle ◽  
Refrigeration System ◽  
Vapour Compression

A remote area power supply using cold thermal storage and wind as the energy source is proposed. The primary objective is to provide a renewable energy remote area power supply with cheaper and more robust storage than lead-acid batteries. The proposal amalgamates a vapour compression refrigeration system with a Rankine cycle engine, both using the same working fluid. A tank of freezing brine acts as the condenser in the Rankine cycle and as the evaporator in the refrigeration cycle but also provides the “energy storage”. Analysis of the system indicates that it is practical and that its performance is comparable with existing battery based systems.

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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