scholarly journals Thermodynamic and Exergoeconomic Analyses of a Novel Combined Cycle Comprised of Vapor-Compression Refrigeration and Organic Rankine Cycles

2019 ◽  
Vol 11 (12) ◽  
pp. 3374 ◽  
Author(s):  
Nima Javanshir ◽  
S. M. Seyed Mahmoudi ◽  
Marc A. Rosen
Keyword(s):  
Unit Cost ◽  
Combined Cycle ◽  
Cycle Performance ◽  
Working Fluid ◽  
Cooling Power ◽  
Vapor Compression ◽  
Exergy Destruction ◽  
Destruction Rate ◽  
Organic Rankine Cycles ◽  
Vapor Compression Refrigeration

In this study, a cooling/power cogeneration cycle consisting of vapor-compression refrigeration and organic Rankine cycles is proposed and investigated. Utilizing geothermal water as a low-temperature heat source, various operating fluids, including R134a, R22, and R143a, are considered for the system to study their effects on cycle performance. The proposed cycle is modeled and evaluated from thermodynamic and thermoeconomic viewpoints by the Engineering Equation Solver (EES) software. Thermodynamic properties as well as exergy cost rates for each stream are found separately. Using R143a as the working fluid, thermal and exergy efficiencies of 27.2% and 57.9%, respectively, are obtained for the cycle. Additionally, the total product unit cost is found to be 60.7 $/GJ. A parametric study is carried out to determine the effects of several parameters, such as turbine inlet pressure, condenser temperature and pressure, boiler inlet air temperature, and pinch-point temperature difference, on the cycle performance. The latter is characterized by such parameters as thermal and exergy efficiencies, refrigeration capacity, produced net power rate, exergy destruction rate, and the production unit cost rates. The results indicate that the system using R134a exhibits the lowest thermal and exergy efficiencies among other working fluids, while the systems using R22 and R143a exhibit the highest energy and exergy efficiencies, respectively. The boiler and turbine contribute the most to the total exergy destruction rate.

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.

scholarly journals Thermodynamic analysis and simulation of a new combined power and refrigeration cycle using artificial neural network

2011 ◽  
Vol 15 (1) ◽  
pp. 29-41 ◽  
Author(s):  
Abdolreza Fazeli ◽  
Hossein Rezvantalab ◽  
Farshad Kowsary
Keyword(s):  
Neural Network ◽  
Artificial Neural Network ◽  
Heat Source ◽  
Exergy Efficiency ◽  
Combined Cycle ◽  
Cycle Performance ◽  
Working Fluid ◽  
Refrigeration Cycle ◽  
Water Mixture ◽  
Artificial Neural

In this study, a new combined power and refrigeration cycle is proposed, which combines the Rankine and absorption refrigeration cycles. Using a binary ammonia-water mixture as the working fluid, this combined cycle produces both power and refrigeration output simultaneously by employing only one external heat source. In order to achieve the highest possible exergy efficiency, a secondary turbine is inserted to expand the hot weak solution leaving the boiler. Moreover, an artificial neural network (ANN) is used to simulate the thermodynamic properties and the relationship between the input thermodynamic variables on the cycle performance. It is shown that turbine inlet pressure, as well as heat source and refrigeration temperatures have significant effects on the net power output, refrigeration output and exergy efficiency of the combined cycle. In addition, the results of ANN are in excellent agreement with the mathematical simulation and cover a wider range for evaluation of cycle performance.

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.

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 Cost Analysis and Optimization of a Geothermal-Based Cogeneration Cycle Using an Ammonia-Water Solution: Thermodynamic and Thermoeconomic Viewpoints

2020 ◽  
Vol 12 (2) ◽  
pp. 484 ◽  
Author(s):  
Nima Javanshir ◽  
Seyed Mahmoudi S. M. ◽  
M. Akbari Kordlar ◽  
Marc A. Rosen
Keyword(s):  
Water Solution ◽  
Unit Cost ◽  
Exergy Efficiency ◽  
Hot Water ◽  
Cycle Performance ◽  
Working Fluid ◽  
Kalina Cycle ◽  
Ammonia Water ◽  
Total Product ◽  
Cogeneration Cycle

A cogeneration cycle for electric power and refrigeration, using an ammonia-water solution as a working fluid and the geothermal hot water as a heat source, is proposed and investigated. The system is a combination of a modified Kalina cycle (KC) which produces power and an absorption refrigeration cycle (ARC) that generates cooling. Geothermal water is supplied to both the KC boiler and the ARC generator. The system is analyzed from thermodynamic and economic viewpoints, utilizing Engineering Equation Solver (EES) software. In addition, a parametric study is carried out to evaluate the effects of decision parameters on the cycle performance. Furthermore, the system performance is optimized for either maximizing the exergy efficiency (EOD case) or minimizing the total product unit cost (COD case). In the EOD case the exergy efficiency and total product unit cost, respectively, are calculated as 34.7% and 15.8$/GJ. In the COD case the exergy efficiency and total product unit cost are calculated as 29.8% and 15.0$/GJ. In this case, the cooling unit cost, c p , c o o l i n g , and power unit cost, c p , p o w e r , are achieved as 3.9 and 11.1$/GJ. These values are 20.4% and 13.2% less than those obtained when the two products are produced separately by the ARC and KC, respectively. The thermoeconomic analysis identifies the more important components, such as the turbine and absorbers, for modification to improve the cost-effectiveness of the system.

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 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.

scholarly journals Energy Analysis of Vapor Compression Refrigeration Cycle Using a New Generation Refrigerants with Low Global Warming Potential

2021 ◽  
Vol 87 (2) ◽  
pp. 106-117
Author(s):  
Rabah Touaibi ◽  
Hasan Koten
Keyword(s):  
Global Warming ◽  
Global Warming Potential ◽  
Energy Analysis ◽  
Coefficient Of Performance ◽  
Cycle Performance ◽  
Refrigeration Cycle ◽  
Vapor Compression ◽  
Vapor Compression Refrigeration Cycle ◽  
Vapor Compression Refrigeration ◽  
Low Global Warming Potential

An energy analysis study carried out on a vapor compression refrigeration cycle using refrigerants with low global warming potential (GWP) of the Hydro-Fluoro-Olefin (HFO) type, in particular R1234yf and R1234ze fluids to replace HFC refrigerants . Computer code was developed using software for solving engineering equations to calculate performance parameters; for this, three HFC type fluids (R134a, R404A and R410A) were selected for a comparative study. The results showed that R1234ze is the best refrigerant among those selected for the mechanical vapor compression refrigeration cycle. The thermodynamic analysis showed the effect of the evaporator temperature (-22 °C to 10 °C) and the condenser temperature (30 °C to 50 °C) on the steam cycle performance. Compression refrigeration, including the coefficient of performance. The results showed that the HFO-R1234ze with low GWP gives the best coefficient of performance of 3.14 close to that of the R134a fluid (3.17). In addition, R1234ze is considered an alternative fluid to R134a for their ecological properties.

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