scholarly journals Performance Analysis and Working Fluid Selection for Single and Two Stages Vapor Compression Refrigeration Cycles

Processes ◽  
2020 ◽  
Vol 8 (9) ◽  
pp. 1017
Author(s):  
Bahaa Saleh ◽  
Ayman A. Aly ◽  
Mishal Alsehli ◽  
Ashraf Elfasakhany ◽  
Mohamed M. Bassuoni
Keyword(s):  
Energy Efficiency ◽  
Environmental Impacts ◽  
High Energy ◽  
Working Fluid ◽  
Vapor Compression ◽  
Alternative Refrigerants ◽  
Two Stage ◽  
Azeotropic Mixtures ◽  
Vapor Compression Refrigeration ◽  
Two Stages

Screening for alternative refrigerants with high energy efficiency and low environmental impacts is one of the highest challenges of the refrigeration sector. This paper investigates the performance and refrigerant screening for single and two stages vapor compression refrigeration cycles. Several pure hydrocarbons, hydrofluorocarbons, hydrofluoroolefins, fluorinated ethers, and binary azeotropic mixtures are proposed as alternative refrigerants to substitute R22 and R134a due to their environmental impacts. The BACKONE equation of state is used to compute the thermodynamic properties of the candidates. The results show that the maximum coefficients of performance (COP) for single and two stage cycles using pure substances are achieved using cyclopentane with values of 4.14 and 4.35, respectively. On the other side, the maximum COP for the two cycles using azeotropic mixtures is accomplished using R134a + RE170 with values of 3.96 and 4.27, respectively. The two-stage cycle presents gain in COP between 5.1% and 19.6% compared with the single-stage cycle based on the used refrigerant. From the obtained results, among all investigated refrigerants, cyclopentane is the most suitable refrigerant for the two cycles from the viewpoint of energy efficiency. However, extra cautions should be taken due to its flammability.

scholarly journals Two-Stage Evaporative Inlet Air Gas Turbine Cooling

Energies ◽  
2021 ◽  
Vol 14 (5) ◽  
pp. 1382
Author(s):  
Obida Zeitoun
Keyword(s):  
Gas Turbine ◽  
Gas Turbines ◽  
Evaporative Cooling ◽  
Air Cooling ◽  
Vapor Compression ◽  
Two Stage ◽  
Turbine Cooling ◽  
Riyadh City ◽  
Vapor Compression Refrigeration ◽  
Gas Turbine Cooling

Gas turbine inlet air-cooling (TIAC) is an established technology for augmenting gas turbine output and efficiency, especially in hot regions. TIAC using evaporative cooling is suitable for hot, dry regions; however, the cooling is limited by the ambient wet-bulb temperature. This study investigates two-stage evaporative TIAC under the harsh weather of Riyadh city. The two-stage evaporative TIAC system consists of indirect and direct evaporative stages. In the indirect stage, air is precooled using water cooled in a cooling tower. In the direct stage, adiabatic saturation cools the air. This investigation was conducted for the GE 7001EA gas turbine model. Thermoflex software was used to simulate the GE 7001EA gas turbine using different TIAC systems including evaporative, two-stage evaporative, hybrid absorption refrigeration evaporative and hybrid vapor-compression refrigeration evaporative cooling systems. Comparisons of different performance parameters of gas turbines were conducted. The added annual profit and payback period were estimated for different TIAC systems.

scholarly journals CFD Analysis of the Optimization of Length of Capillary Tube for a Vapor Compression Refrigeration System

2021 ◽  
Vol 9 (8) ◽  
pp. 2567-2578
Author(s):  
Ms. K. P. Bhangle
Keyword(s):  
Capillary Tube ◽  
Flow Analysis ◽  
Small Diameter ◽  
Flow Characteristics ◽  
Working Fluid ◽  
Vapor Compression ◽  
Adiabatic Flow ◽  
Ansys Cfx ◽  
Vapor Compression Refrigeration ◽  
R 134A

Abstract: The capillary tube is commonly employed in refrigerant flow control systems. As a result, the capillary tube's performance is optimal for good refrigerant flow. Many scholars concluded performance utilising experimental, theoretical, and analysis-based methods. This paper examines the flow analysis of a refrigerant within a capillary tube under adiabatic flow circumstances. For a given mass flow rate, the suggested model can predict flow characteristics in adiabatic capillary tubes. In the current work, R-134a refrigerant has been replaced by R600a refrigerant as a working fluid inside the capillary tube, and the capillary tube design has been modified by altering length and diameter, which were obtained from reputable literature. The analysis is carried out using the ANSYS CFX 16.2 software. The results show thatutilising a small diameter and a long length (R600a refrigerant flow) is superior to the present helical capillary tube. The most appropriate helical coiled design with a diameter of 0.8 mm and a length of 3 m is proposed. Keywords: Capillary Tube, Condenser, Refrigeration effect, CFD.

scholarly journals Calculated and experimental evaluation heat pump distiller on pentane as working substance

2020 ◽  
Vol 324 ◽  
pp. 02007
Author(s):  
Gennady A. Ilyn ◽  
Ilya I. Malafeev ◽  
Vladimir B. Sapojnikov
Keyword(s):  
High Temperature ◽  
High Efficiency ◽  
Recovery Phase ◽  
High Energy ◽  
Heat Pumps ◽  
Working Fluid ◽  
Vapor Compression ◽  
The Cost ◽  
Reliable Methods ◽  
High Temperature Vapor

One of the most common and reliable methods of water treatment is the method of thermal distillation. Despite the reliability of the method, its application is constrained by high energy intensity. The most effective way to reduce the cost of production of distillate is the use of thermal transformers, providing regenerate and heat recovery phase transformations of the distillate. The use of working fluid with the most favorable thermodynamic properties is of paramount importance for the creation of high efficiency thermotransformers. The work is considered working fluid for high-temperature heat pumps and the results of the calculation-experimental study of high-temperature vapor compression heat-pumping distiller on natural working substance n-pentan.

Thermodynamic Analysis and Working Fluid Optimization of a Combined ORC-VCC System Using Waste Heat From a Marine Diesel Engine

2014 ◽  
Author(s):  
Oumayma Bounefour ◽  
Ahmed Ouadha
Keyword(s):  
Thermodynamic Analysis ◽  
Waste Heat ◽  
Operating Conditions ◽  
Working Fluid ◽  
Vapor Compression ◽  
Marine Diesel ◽  
Vapor Compression Refrigeration ◽  
Propylene Yield ◽  
Fluid Optimization ◽  
Propane Butane

This paper examines through a thermodynamic analysis the feasibility of using waste heat from marine Diesel engines to drive a vapor compression refrigeration system. Several working fluids including propane, butane, isobutane and propylene are considered. Results showed that isobutane and Butane yield the highest performance, whereas propane and propylene yield negligible improvement compared to R134a for operating conditions considered.

scholarly journals Energy and Exergy Analysis of Combined Organic Rankine Cycle-Single and Dual Evaporator Vapor Compression Refrigeration Cycle

2019 ◽  
Vol 9 (23) ◽  
pp. 5028 ◽  
Author(s):  
Pektezel ◽  
Acar
Keyword(s):  
Exergy Analysis ◽  
Organic Rankine Cycle ◽  
Rankine Cycle ◽  
Working Fluid ◽  
Refrigeration Cycle ◽  
Vapor Compression ◽  
Exergy Destruction ◽  
Energy And Exergy ◽  
Energy And Exergy Analysis ◽  
Vapor Compression Refrigeration

This paper presents energy and exergy analysis of two vapor compression refrigeration cycles powered by organic Rankine cycle. Refrigeration cycle of combined system was designed with single and dual evaporators. R134a, R1234ze(E), R227ea, and R600a fluids were used as working fluids in combined systems. Influences of different parameters such as evaporator, condenser, boiler temperatures, and turbine and compressor isentropic efficiencies on COPsys and ƞex,sys were analyzed. Second law efficiency, degree of thermodynamic perfection, exergy destruction rate, and exergy destruction ratio were detected for each component in systems. R600a was determined as the most efficient working fluid for proposed systems. Both COPsys and ƞex,sys of combined ORC-single evaporator VCR cycle was detected to be higher than the system with dual evaporator.

Design and rating of a two-stage vapor-compression refrigeration system

Energy ◽  
1998 ◽  
Vol 23 (10) ◽  
pp. 867-878 ◽  
Author(s):  
Jameel-Ur-Rehman Khan ◽  
Syed M. Zubair
Keyword(s):  
Vapor Compression ◽  
Refrigeration System ◽  
Two Stage ◽  
Vapor Compression Refrigeration

scholarly journals Performance Analysis of Solar Combined Ejector-Vapor Compression Cycle Using Environmental Friendly Refrigerants

2013 ◽  
Vol 14 (1) ◽  
Author(s):  
A. B. Kasaeian ◽  
S. Daviran
Keyword(s):  
Internal Heat ◽  
Exergy Efficiency ◽  
Operating Conditions ◽  
Working Fluid ◽  
Vapor Compression ◽  
Refrigeration System ◽  
Environmental Friendly ◽  
Vapor Compression Cycle ◽  
Compression Cycle ◽  
Vapor Compression Refrigeration

In this study, a new model of a solar combined ejector-vapor compression refrigeration system has been considered. The system is equipped with an internal heat exchanger to enhance the performance of the cycle. The effects of working fluid and operating conditions on the system performance including COP, entrainment ratio (ω), compression ratio (rp) and exergy efficiency were investigated. Some working fluids suggested are: R114, R141b, R123, R245fa, R600a, R365mfc, R1234ze(e) and R1234ze(z). The results show that R114 and R1234ze(e) yield the highest COP and exergy efficiency followed by R123, R245fa, R365mfc, R141b, R152a and R600a. It is noticed that the COP value of the new solar ejector-vapor compression refrigeration cycle is higher than that of the conventional ejector cycle with R1234ze(e) for all operating conditions. This paper also demonstrates that R1234ze(e) will be a suitable refrigerant in the solar combined ejector-vapor compression refrigeration system, due to its environmental friendly properties and better performance. ABSTRAK: Kajian ini menganalisa model baru sistem penyejukan mampatan gabungan ejektor-wap solar.Sistem ini dilengkapi dengan penukar haba dalaman untuk meningkatkan prestasi kitaran.Kesan bendalir bekerja dan keadaan operasi pada prestasi sistem termasuk COP, nisbah pemerangkapan (ω), nisbah mampatan (rp) dan kecekapan eksergi telah disiasat.Beberapa bendalir bekerja yang dicadangkan adalah: R114, R141b, R123, R245fa, R600a, R365mfc, R1234ze(e) dan R1234ze(z).Hasil kajian menunjukkan R114 dan R1234ze(e) menghasilkan COP dan kecekapan eksergi tertinggi diikuti oleh R123, R245fa, R365mfc, R141b, R152a dan R600a.Didapati nilai COP kitaran penyejukan mampatan bagi ejektor-wap solar baru adalah lebih tinggi daripada kitaran ejektor konvensional dengan R1234ze(e) bagi semua keadaan operasi.Kertas kerja ini juga menunjukkan bahawa R1234ze(e) boleh menjadi penyejuk yang sesuai dalam sistem penyejukan mampatan gabungan ejektor -wap solar, kerana ianya mempunyai prestasi yang lebih baik serta sifatnya yang lebih mesra alam sekitar. KEYWORDS: environmental friendly refrigerants; solar combined ejector-vapor compression cycle; R1234ze(e)

scholarly journals Low temperature vacuum sublimation refrigerators on carbon dioxide as working fluid

2020 ◽  
Vol 324 ◽  
pp. 02004
Author(s):  
Artem Frolovich Porutchikov ◽  
Dmitriy Pavlovich Trubin
Keyword(s):  
Carbon Dioxide ◽  
Freeze Drying ◽  
Working Fluid ◽  
Energy Costs ◽  
Vapor Compression ◽  
Vacuum Sublimation ◽  
Environmental Friendliness ◽  
Environmental Requirements ◽  
Vapor Compression Refrigeration ◽  
Refrigeration Machine

The paper presents the results of theoretical and experimental analysis of a vacuum-freeze-drying refrigeration machine based on carbon dioxide. Such refrigeration machines can be equipped with refrigerators for the needs of medicine, where low temperatures are widely in demand in the range from minus 80 degrees Celsius to minus 130 degrees Celsius. The problem of developing alternative refrigeration machines is dictated by modern environmental requirements for working substances, which are gradually being tightened and soon the use of familiar freons will become impossible. For the air conditioning and commercial refrigeration industry, new substances are being actively developed, such as hydrofluoroolefins (HFOs), hydrocarbons can also serve as substitutes for hydrofluorocarbons and their mixtures, but it must be considered that they are combustible and explosive. A carbon dioxide vacuum sublimation unit may be an alternative to modern freon vapor compression refrigeration units for the indicated temperature range, but subject to comparable energy costs during its operation. The article examined the three-stage and four-stage cycles of a vacuum-freeze-drying refrigeration machine, conducted their theoretical comparison in terms of COP with a cascade cycle on hydrocarbon working substances. It can be noted that the COP of the considered cycles are close, but the environmental friendliness, safety and non-combustibility of carbon dioxide gives the advantages of a vacuum freeze-drying refrigeration machine.

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