This document presents a theoretical analysis of a vapor compression refrigeration system using refrigerants R-22, R407C, and R410A. Equations are developed based on the first and second laws of thermodynamics to model the system and analyze parameters such as coefficient of performance (COP), exergetic efficiency, and exergy destruction ratio (EDR). Results show R410A has the highest relative capacity change with increased subcooling degree and COP increase with higher evaporator temperatures. Exergetic efficiency is maximized and EDR minimized at evaporator temperatures of -30 to -35°C. R410A performance is better than R407C based on the thermodynamic analysis.
REVIEW OF CASCADE REFRIGERATION SYSTEM WITH DIFFERENT REFRIGERANT PAIRSijiert bestjournal
A Comparative assessment of a cascade refrigeration cycle with different refrigerant pair is presented in this paper. R744 is used in Low-temper ature (LT) cycle whereas R134a,R290,R717 and R404A (R125(44%)/R143a(52%) /R134a(4%)) are use d in the High-temperature (HT) cycle. The effects of the thermodynamic parameters on the cascade system are evaluated with an objective to find the best working fluid pair based on COP. R 744-717 is selected based on thermodynamic and environmental performance. A parametric evaluation is also presented for R744-R717 working pair by varying parameters like sub cooling,superheatin g,evaporating,condensing temperature and temperature difference in the cascade condenser of the system.
Thermodynamic Analysis of a Cascade Refrigeration System Based On Carbon Diox...IJERA Editor
Thermodynamic analysis of a cascade refrigeration system that uses carbon dioxide-ammonia (R744-R717) as refrigerant is presented in this paper to determine the optimum condensing temperature of the cascade condenser at given design parameters, to maximize the COP of the system. The design and operating parameters considered in this study include (1) condensing, sub cooling, evaporating and super heating temperatures in the ammonia (R717) high-temperature circuit, (2) temperature difference in the cascade heat exchanger, and (3) evaporating, superheating, condensing and sub cooling in the carbon dioxide (R744) low-temperature circuit. A multilinear regression analysis was employed in order to develop two useful correlations for maximum COP, and optimum condensing temperature.
International Journal of Engineering Research and Applications (IJERA) is an open access online peer reviewed international journal that publishes research and review articles in the fields of Computer Science, Neural Networks, Electrical Engineering, Software Engineering, Information Technology, Mechanical Engineering, Chemical Engineering, Plastic Engineering, Food Technology, Textile Engineering, Nano Technology & science, Power Electronics, Electronics & Communication Engineering, Computational mathematics, Image processing, Civil Engineering, Structural Engineering, Environmental Engineering, VLSI Testing & Low Power VLSI Design etc.
REVIEW OF CASCADE REFRIGERATION SYSTEM WITH DIFFERENT REFRIGERANT PAIRSijiert bestjournal
A Comparative assessment of a cascade refrigeration cycle with different refrigerant pair is presented in this paper. R744 is used in Low-temper ature (LT) cycle whereas R134a,R290,R717 and R404A (R125(44%)/R143a(52%) /R134a(4%)) are use d in the High-temperature (HT) cycle. The effects of the thermodynamic parameters on the cascade system are evaluated with an objective to find the best working fluid pair based on COP. R 744-717 is selected based on thermodynamic and environmental performance. A parametric evaluation is also presented for R744-R717 working pair by varying parameters like sub cooling,superheatin g,evaporating,condensing temperature and temperature difference in the cascade condenser of the system.
Thermodynamic Analysis of a Cascade Refrigeration System Based On Carbon Diox...IJERA Editor
Thermodynamic analysis of a cascade refrigeration system that uses carbon dioxide-ammonia (R744-R717) as refrigerant is presented in this paper to determine the optimum condensing temperature of the cascade condenser at given design parameters, to maximize the COP of the system. The design and operating parameters considered in this study include (1) condensing, sub cooling, evaporating and super heating temperatures in the ammonia (R717) high-temperature circuit, (2) temperature difference in the cascade heat exchanger, and (3) evaporating, superheating, condensing and sub cooling in the carbon dioxide (R744) low-temperature circuit. A multilinear regression analysis was employed in order to develop two useful correlations for maximum COP, and optimum condensing temperature.
International Journal of Engineering Research and Applications (IJERA) is an open access online peer reviewed international journal that publishes research and review articles in the fields of Computer Science, Neural Networks, Electrical Engineering, Software Engineering, Information Technology, Mechanical Engineering, Chemical Engineering, Plastic Engineering, Food Technology, Textile Engineering, Nano Technology & science, Power Electronics, Electronics & Communication Engineering, Computational mathematics, Image processing, Civil Engineering, Structural Engineering, Environmental Engineering, VLSI Testing & Low Power VLSI Design etc.
Experimental Investigation of a Household Refrigerator Using Evaporative-Cool...inventy
The objective of this paper was to investigate experimentally the effect of Evaporative-cooled condenser in a household refrigerator. The experiment was done using HCF134a as the refrigerant. The performance of the household refrigerator with air-cooled and Evaporative-cooled condenser was compared for different load conditions. The results indicate that the refrigerator performance had improved when evaporative-cooled condenser was used instead of air-cooled condenser on all load conditions. Evaporativecooled condenser reduced the energy consumption when compared with the air-cooled condenser. There was also an enhancement in coefficient of performance (COP) when evaporative-cooled condenser was used instead of air-cooled condenser. The Evaporative cooled heat exchanger was designed and the system was modified by retrofitting it, instead of the conventional air-cooled condenser by making drop wise condensation using water and forced circulation over the condenser. From the experimental analysis it is observed that the COP of evaporative cooled system increased by 13.44% compared to that of air cooled system. So the overall efficiency and refrigerating effect is increased. In minimum constructional, maintenance and running cost, the system is much useful for domestic purpose. This study also revealed that combining a evaporative cooled system along with conventional water cooled system under the condition that the defrost water obtained from the freezer is used for drop wise condensation over condenser and water cooled condensation of the condenser at the bottom using remaining defrost water would reduce the power consumption, work done and hence further increase in refrigerating effect of the system. The study has shown that such a system is technically feasible and economically viable
Effect of approching temperature on the performance and size of li br water v...eSAT Publishing House
IJRET : International Journal of Research in Engineering and Technology is an international peer reviewed, online journal published by eSAT Publishing House for the enhancement of research in various disciplines of Engineering and Technology. The aim and scope of the journal is to provide an academic medium and an important reference for the advancement and dissemination of research results that support high-level learning, teaching and research in the fields of Engineering and Technology. We bring together Scientists, Academician, Field Engineers, Scholars and Students of related fields of Engineering and Technology
International Journal of Engineering Research and Applications (IJERA) is an open access online peer reviewed international journal that publishes research and review articles in the fields of Computer Science, Neural Networks, Electrical Engineering, Software Engineering, Information Technology, Mechanical Engineering, Chemical Engineering, Plastic Engineering, Food Technology, Textile Engineering, Nano Technology & science, Power Electronics, Electronics & Communication Engineering, Computational mathematics, Image processing, Civil Engineering, Structural Engineering, Environmental Engineering, VLSI Testing & Low Power VLSI Design etc.
A REVIEW PAPER ON ANALYSIS OF AUTOMOBILE RADIATORijsrd.com
An Automotive engine cooling system takes out of excess heat produced during engine operation. An automobile cooling system regulates engine surface temperature for engine optimum efficiency. Recent advancement and development in engine for power forced engine cooling system to develop new strategies to improve its performance efficiency. Also to reduce fuel consumption along with controlling engine emission to mitigate environmental pollution norms. This paper throws light on parameters which influence radiator performance along with reviews some of the conventional and modern approaches to enhance radiator performance. This review paper Focus on the various research papers regarding experimental, CFD and Numerical analysis to improving automobile radiator efficiency.
STUDY OF PERFORMANCE EVALUATION OF DOMESTIC REFRIGERATOR WORKING WITH MIXTURE...IAEME Publication
In many developing countries Like India, most of the vapor compression based refrigeration, air conditioning and heat pump systems continue to run on halogenated refrigerants due to its excellent thermodynamic and thermo-physical properties apart from the low cost. However, the halogenated refrigerants have adverse environmental impacts such as ozone depletion potential (ODP) and global warming potential (GWP). This project is devoted to feasibility study of substitution of LPG which is locally available and comprises 24.4% propane, 56.4% butane and 17.2% isobutene. The LPG is cheap and possesses an environmentally friendly nature with no ozone depletion potential (ODP). It is used in Libya for cooking purposes .Experimental result showed that the LPG refrigerant with charge of 25g worked well under unloaded condition
To study the application of nanorefrigerant in refrigeration system a revieweSAT Journals
Abstract In past time only refrigerants were used in refrigeration process and they were having a global warming coefficient at high level. Now, as time change the modern techniques are coming into existence with the help of them the refrigeration process become more efficient and safe as compare to previous in atmospheric prospective. This review paper is based on the nanotechnologies used in present time in refrigeration system like vapour compression refrigeration system, domestic refrigerator and air conditioner etc. The nano refrigerant is nothing but the combined form of nano particle with the refrigerant. The nanorefrigerant can be formed by two ways (1) by mixing nano particles with refrigerant in gaseous form, (2) by mixing nano particles to lubricant. We will combine different nano particles having the same diameter and same volume fraction with the lubricant to study the nature of thermo-physical properties in refrigeration process. There would be some parameters that can be studied by this experiment like energy consumption, heat transfer, cop etc. Keywords: nano particles, nano refrigerant, heat transfer coefficient, COP, Energy consumption.
CFD Simulation and Heat Transfer Analysis of Automobile Radiator using Helica...IJERD Editor
To ensure smooth running of an automotive vehicle under any variable load conditions, one of the major systems necessary is the cooling system. Automobile radiators are becoming highly power-packed with increasing power to weight or volume ratio. Computational Fluid Dynamics (CFD) is one of the important software tools to access preliminary design and the performance of the radiator. In this paper, a 55 hp engine radiator data is taken for analysis in CFD. The model is done Pro-E software and imported in ANSYS-12. Helical tubes are considered for the radiator with two different pitches like 15mm & 20mm. The comparison is done for different mass flow rates like 2.3, 2.0, 1.0, 0.5 kg/sec in helical type tubes. It is found that there is more heat dissipation rate in 15mm pitch helical tubes compared to 20mm pitch helical tubes. Maximum temperature drop & minimum pressure drop occurs in case of 0.5 kg/sec of mass flow rate. It is observed that with increased mass flow rate, there is decrease in temperature drop & increase in pressure drop
EXPERIMENTAL STUDY ON A DOMESTIC REFRIGERATOR USING LPG AS A REFRIGARANTIAEME Publication
This project is devoted to feasibility study of substitution of LPG (60% Propane and 40 % commercial Butane) as refrigerant instead of R134a in a domestic refrigerator. An experimental performance study on a VCR system
with LPG as refrigerant was conducted and compared with R134a.The VCR system was initially designed to operate with R134a.
Modeling and Fluid Flow Analysis of Wavy Fin Based Automotive RadiatorIJERA Editor
In continuous technological development, an automotive industry has increased the demand for high efficiency engines. A high efficiency engines in not only based on its performance but also for better fuel economy and less emission rate. Radiator is one of the important parts of the internal combustion engine cooling system. The manufacturing cost of the radiator is 20 percent of the whole cost of the engine. So improving the performance and reducing cost of radiators are necessary research. For higher cooling capacity of radiator, addition of fins is one of the approaches to increase the cooling rate of the radiator. In addition, heat transfer fluids at air and fluid side such as water and ethylene glycol exhibit very low thermal conductivity. As a result there is a need for new and innovative heat transfer fluids, known as “Nano fluid” for improving heat transfer rate in an automotive radiator. Recently there have been considerable research findings highlighting superior heat transfer performances of nanofluids about 15-25% of heat transfer enhancement can be achieved by using types of nanofluids. With these specific characteristics, the size and weight of an automotive car radiator can be reduced without affecting its heat transfer performance. An automotive radiator (Wavy fin type) model is modeled on modeling software CATIA V5 and performance evaluation is done on pre-processing software ANSYS 14.0. The temperature and velocity distribution of coolant and air are analyzed by using Computational fluid dynamics environment software CFX. Results have shown that the rate of heat transfer is better when nano fluid (Si C + water) is used as coolant, than the conventional coolant.
Distribution, Habitat Utilization and Threats to Chinese Pangolin (Manis Pent...NAAR Journal
The Chinese Pangolin (Manis pentadactyla) is a unique mammal
having stiff scales, body shape slender like a reptile, burrow living and
highly nocturnal. It is receiving less scientific attention therefore
information on its ecology, behavior, status and distribution is still
scarce in Nepal. Pangolins are distributed in many districts and
protected areas of Nepal but are threatened due to habitat destruction,
illegal trade and lack of awareness. Thus, this research was conducted
to assess the distribution, habitat utilization and threats to Chinese
Pangolin in Mahabharat and Chure community forests of Sindhuli
district. The primary data were collected by using the methods adopted
in National Pangolin Survey, Nepal (2016). The sample size for
scheduled questionnaire survey was calculated by using the formula
given by Krejice and Morgan in 1970. The secondary data were
collected from the DFO, Sector forest office and community forest
office. Through field survey within the transect of 500 meters;
distribution of burrows, their geographical coordinates, slope,
elevation, canopy cover, soil moisture, soil colour and texture,
distance to settlement, water and road and number of ants/termites
mound were recorded. A total of 348 burrows were recorded including
206 (91 active, 115 inactive) in Mahabharat Community Forest and
142 (57 active, 85 inactive) in Chure Community Forest. The
elevation range of species was from 1400 m to 1700 m with maximum
number of burrows at slope range of 30⁰-40⁰ in Mahabharat
community forest. However, in Chure community forest, the elevation
range of species was from 900 m to 1300 m with maximum number of
burrows at slope range of 20⁰-30⁰. The highest frequency of burrows
was recorded in brown and light yellow colour soil in Mahabharat and
Chure community forest respectively. Mostly the burrows were
recorded in Schima wallichii and Shorea robusta dominant forests in Mahabharat and Chure community forest respectively. Poaching for
meat and traditional medicine and habitat destruction were major
threats to pangolin at the sites and their conservation status was found
to be worse.
Experimental Investigation of a Household Refrigerator Using Evaporative-Cool...inventy
The objective of this paper was to investigate experimentally the effect of Evaporative-cooled condenser in a household refrigerator. The experiment was done using HCF134a as the refrigerant. The performance of the household refrigerator with air-cooled and Evaporative-cooled condenser was compared for different load conditions. The results indicate that the refrigerator performance had improved when evaporative-cooled condenser was used instead of air-cooled condenser on all load conditions. Evaporativecooled condenser reduced the energy consumption when compared with the air-cooled condenser. There was also an enhancement in coefficient of performance (COP) when evaporative-cooled condenser was used instead of air-cooled condenser. The Evaporative cooled heat exchanger was designed and the system was modified by retrofitting it, instead of the conventional air-cooled condenser by making drop wise condensation using water and forced circulation over the condenser. From the experimental analysis it is observed that the COP of evaporative cooled system increased by 13.44% compared to that of air cooled system. So the overall efficiency and refrigerating effect is increased. In minimum constructional, maintenance and running cost, the system is much useful for domestic purpose. This study also revealed that combining a evaporative cooled system along with conventional water cooled system under the condition that the defrost water obtained from the freezer is used for drop wise condensation over condenser and water cooled condensation of the condenser at the bottom using remaining defrost water would reduce the power consumption, work done and hence further increase in refrigerating effect of the system. The study has shown that such a system is technically feasible and economically viable
Effect of approching temperature on the performance and size of li br water v...eSAT Publishing House
IJRET : International Journal of Research in Engineering and Technology is an international peer reviewed, online journal published by eSAT Publishing House for the enhancement of research in various disciplines of Engineering and Technology. The aim and scope of the journal is to provide an academic medium and an important reference for the advancement and dissemination of research results that support high-level learning, teaching and research in the fields of Engineering and Technology. We bring together Scientists, Academician, Field Engineers, Scholars and Students of related fields of Engineering and Technology
International Journal of Engineering Research and Applications (IJERA) is an open access online peer reviewed international journal that publishes research and review articles in the fields of Computer Science, Neural Networks, Electrical Engineering, Software Engineering, Information Technology, Mechanical Engineering, Chemical Engineering, Plastic Engineering, Food Technology, Textile Engineering, Nano Technology & science, Power Electronics, Electronics & Communication Engineering, Computational mathematics, Image processing, Civil Engineering, Structural Engineering, Environmental Engineering, VLSI Testing & Low Power VLSI Design etc.
A REVIEW PAPER ON ANALYSIS OF AUTOMOBILE RADIATORijsrd.com
An Automotive engine cooling system takes out of excess heat produced during engine operation. An automobile cooling system regulates engine surface temperature for engine optimum efficiency. Recent advancement and development in engine for power forced engine cooling system to develop new strategies to improve its performance efficiency. Also to reduce fuel consumption along with controlling engine emission to mitigate environmental pollution norms. This paper throws light on parameters which influence radiator performance along with reviews some of the conventional and modern approaches to enhance radiator performance. This review paper Focus on the various research papers regarding experimental, CFD and Numerical analysis to improving automobile radiator efficiency.
STUDY OF PERFORMANCE EVALUATION OF DOMESTIC REFRIGERATOR WORKING WITH MIXTURE...IAEME Publication
In many developing countries Like India, most of the vapor compression based refrigeration, air conditioning and heat pump systems continue to run on halogenated refrigerants due to its excellent thermodynamic and thermo-physical properties apart from the low cost. However, the halogenated refrigerants have adverse environmental impacts such as ozone depletion potential (ODP) and global warming potential (GWP). This project is devoted to feasibility study of substitution of LPG which is locally available and comprises 24.4% propane, 56.4% butane and 17.2% isobutene. The LPG is cheap and possesses an environmentally friendly nature with no ozone depletion potential (ODP). It is used in Libya for cooking purposes .Experimental result showed that the LPG refrigerant with charge of 25g worked well under unloaded condition
To study the application of nanorefrigerant in refrigeration system a revieweSAT Journals
Abstract In past time only refrigerants were used in refrigeration process and they were having a global warming coefficient at high level. Now, as time change the modern techniques are coming into existence with the help of them the refrigeration process become more efficient and safe as compare to previous in atmospheric prospective. This review paper is based on the nanotechnologies used in present time in refrigeration system like vapour compression refrigeration system, domestic refrigerator and air conditioner etc. The nano refrigerant is nothing but the combined form of nano particle with the refrigerant. The nanorefrigerant can be formed by two ways (1) by mixing nano particles with refrigerant in gaseous form, (2) by mixing nano particles to lubricant. We will combine different nano particles having the same diameter and same volume fraction with the lubricant to study the nature of thermo-physical properties in refrigeration process. There would be some parameters that can be studied by this experiment like energy consumption, heat transfer, cop etc. Keywords: nano particles, nano refrigerant, heat transfer coefficient, COP, Energy consumption.
CFD Simulation and Heat Transfer Analysis of Automobile Radiator using Helica...IJERD Editor
To ensure smooth running of an automotive vehicle under any variable load conditions, one of the major systems necessary is the cooling system. Automobile radiators are becoming highly power-packed with increasing power to weight or volume ratio. Computational Fluid Dynamics (CFD) is one of the important software tools to access preliminary design and the performance of the radiator. In this paper, a 55 hp engine radiator data is taken for analysis in CFD. The model is done Pro-E software and imported in ANSYS-12. Helical tubes are considered for the radiator with two different pitches like 15mm & 20mm. The comparison is done for different mass flow rates like 2.3, 2.0, 1.0, 0.5 kg/sec in helical type tubes. It is found that there is more heat dissipation rate in 15mm pitch helical tubes compared to 20mm pitch helical tubes. Maximum temperature drop & minimum pressure drop occurs in case of 0.5 kg/sec of mass flow rate. It is observed that with increased mass flow rate, there is decrease in temperature drop & increase in pressure drop
EXPERIMENTAL STUDY ON A DOMESTIC REFRIGERATOR USING LPG AS A REFRIGARANTIAEME Publication
This project is devoted to feasibility study of substitution of LPG (60% Propane and 40 % commercial Butane) as refrigerant instead of R134a in a domestic refrigerator. An experimental performance study on a VCR system
with LPG as refrigerant was conducted and compared with R134a.The VCR system was initially designed to operate with R134a.
Modeling and Fluid Flow Analysis of Wavy Fin Based Automotive RadiatorIJERA Editor
In continuous technological development, an automotive industry has increased the demand for high efficiency engines. A high efficiency engines in not only based on its performance but also for better fuel economy and less emission rate. Radiator is one of the important parts of the internal combustion engine cooling system. The manufacturing cost of the radiator is 20 percent of the whole cost of the engine. So improving the performance and reducing cost of radiators are necessary research. For higher cooling capacity of radiator, addition of fins is one of the approaches to increase the cooling rate of the radiator. In addition, heat transfer fluids at air and fluid side such as water and ethylene glycol exhibit very low thermal conductivity. As a result there is a need for new and innovative heat transfer fluids, known as “Nano fluid” for improving heat transfer rate in an automotive radiator. Recently there have been considerable research findings highlighting superior heat transfer performances of nanofluids about 15-25% of heat transfer enhancement can be achieved by using types of nanofluids. With these specific characteristics, the size and weight of an automotive car radiator can be reduced without affecting its heat transfer performance. An automotive radiator (Wavy fin type) model is modeled on modeling software CATIA V5 and performance evaluation is done on pre-processing software ANSYS 14.0. The temperature and velocity distribution of coolant and air are analyzed by using Computational fluid dynamics environment software CFX. Results have shown that the rate of heat transfer is better when nano fluid (Si C + water) is used as coolant, than the conventional coolant.
Distribution, Habitat Utilization and Threats to Chinese Pangolin (Manis Pent...NAAR Journal
The Chinese Pangolin (Manis pentadactyla) is a unique mammal
having stiff scales, body shape slender like a reptile, burrow living and
highly nocturnal. It is receiving less scientific attention therefore
information on its ecology, behavior, status and distribution is still
scarce in Nepal. Pangolins are distributed in many districts and
protected areas of Nepal but are threatened due to habitat destruction,
illegal trade and lack of awareness. Thus, this research was conducted
to assess the distribution, habitat utilization and threats to Chinese
Pangolin in Mahabharat and Chure community forests of Sindhuli
district. The primary data were collected by using the methods adopted
in National Pangolin Survey, Nepal (2016). The sample size for
scheduled questionnaire survey was calculated by using the formula
given by Krejice and Morgan in 1970. The secondary data were
collected from the DFO, Sector forest office and community forest
office. Through field survey within the transect of 500 meters;
distribution of burrows, their geographical coordinates, slope,
elevation, canopy cover, soil moisture, soil colour and texture,
distance to settlement, water and road and number of ants/termites
mound were recorded. A total of 348 burrows were recorded including
206 (91 active, 115 inactive) in Mahabharat Community Forest and
142 (57 active, 85 inactive) in Chure Community Forest. The
elevation range of species was from 1400 m to 1700 m with maximum
number of burrows at slope range of 30⁰-40⁰ in Mahabharat
community forest. However, in Chure community forest, the elevation
range of species was from 900 m to 1300 m with maximum number of
burrows at slope range of 20⁰-30⁰. The highest frequency of burrows
was recorded in brown and light yellow colour soil in Mahabharat and
Chure community forest respectively. Mostly the burrows were
recorded in Schima wallichii and Shorea robusta dominant forests in Mahabharat and Chure community forest respectively. Poaching for
meat and traditional medicine and habitat destruction were major
threats to pangolin at the sites and their conservation status was found
to be worse.
IJREI_A thermodynamic analysis of ejector type vapour refrigeration system us...Husain Mehdi
A thermodynamic analysis on Ejector Refrigeration Cycle (ERC), have been performed using eco-friendly refrigerants (i.e.R-404A, R-410A, R-407C, R-423A, R-500, R-502 and R-507C ) A numerical computation is carried out for finding COP, Second Law Efficiency (ηII) , Refrigeration Effect (RE) and Heat Input (Qin) of the ERC along with the variation in boiler temperature (Tb) , condenser temperature (Tc) and evaporator temperature (Te) for ecofriendly refrigerants for the ranges of the temperatures where the evaporator temperature is varying from 253K to 273K, with varying condenser temperature from 313K to 328K and with varying boiling temperature from 320 K to 345K. The maximum first Law Efficiency (ηI) is found in the range of 1.5-1.8 with fluid R-404A and condenser temperature 328K. At 253K evaporator temperature R-404A is working with maximum Second Law Efficiency (ηII) 37%. For the entire range of boiling temperature R-410A is having maximum Second Law Efficiency (ηII) except at 345K where R-404A is highest. The refrigeration effect is the maximum and is in the range of 200kW to 220kW for R-410A for all the ranges of temperatures. The highest COP is associated with R-404A with temperature variations
IJREI_Thermodynamic study of R134a in Vapour Compression Refrigeration System...Husain Mehdi
Thermodynamic analysis of an ideal vapour compression refrigeration system is done using refrigerants R134a.This Energy-Exergy analysis is carried out by developed mathematical model. Various parameters are numerically computed are first law efficiency in terms of coefficient of performance (COP) of the system both ideal case and actual experimental and exergetic efficiency and exergy destruction ratio have been computed . The eco-friendly R134a refrigerant gives lower COP than R22. Comparing with R22, R134a takes more compressor power and second law efficiency (exergetic efficiency) of VCRS is also lower than using R22. Due to higher GWP and ODP of R22, R134a can be used for domestic / commercial and industrial applications.
International Journal of Engineering Research and Applications (IJERA) is an open access online peer reviewed international journal that publishes research and review articles in the fields of Computer Science, Neural Networks, Electrical Engineering, Software Engineering, Information Technology, Mechanical Engineering, Chemical Engineering, Plastic Engineering, Food Technology, Textile Engineering, Nano Technology & science, Power Electronics, Electronics & Communication Engineering, Computational mathematics, Image processing, Civil Engineering, Structural Engineering, Environmental Engineering, VLSI Testing & Low Power VLSI Design etc.
Simulation of N2 Gas Separation Process from AirIOSR Journals
Various components of air have been separated for different purposes for their easy availability in the atmosphere. Among those components Nitrogen separation process is very important in chemical engineering sector since it has wide usage in different processes. There are various technologies that are used for the separation of nitrogen. Among those most common is via LINDE-HAMPSON cycle. This paper presents analysis of thermodynamic cycle commonly used for liquefaction of Nitrogen (N2) under given set of operating condition and efficiencies. The liquefying temperature of Nitrogen being -200oC is taken into consideration. This paper also presents the simulation of this process HYSYS for the separation of N2 from air. Simulation result gives the value of product nitrogen purity of 91.75%
OPTIMIZATION OF AN ORGANIC RANKINE CYCLE IN ENERGY RECOVERY FROM EXHAUST GASE...IAEME Publication
This paper describes thermal analysis and optimization of an organic Rankine cycle (ORC) integrated with a power generating stationary diesel engine. A simple ORC, with a regenerator, is considered here as a bottoming cycle for producing additional power by recovering waste energy
from the exhaust gases of the engine. Taking evaporation pressure and condensation temperature as two decision variables, a genetic algorithm is used for simultaneously maximizing three objective functions - exergy efficiency, thermal efficiency, and specific network.
an experiment on a co2 air conditioning system with copper heat exchangersINFOGAIN PUBLICATION
This paper presented an experiment on a CO2 air conditioning system with copper heat exchangers. In this study, the compressor and cooler were tested with hydraulic method to determine the deformed and torn temperatures. The results show that conventional compressor is not suitable for using high pressure, due to the COP of cycle is very low (0.5 only). With CO2 compressor, the cycle can be achieved COP of 3.07 at the evaporative temperature of 10C. This value equals with COP of commercial air conditioning system presently.
Dev Dives: Train smarter, not harder – active learning and UiPath LLMs for do...UiPathCommunity
💥 Speed, accuracy, and scaling – discover the superpowers of GenAI in action with UiPath Document Understanding and Communications Mining™:
See how to accelerate model training and optimize model performance with active learning
Learn about the latest enhancements to out-of-the-box document processing – with little to no training required
Get an exclusive demo of the new family of UiPath LLMs – GenAI models specialized for processing different types of documents and messages
This is a hands-on session specifically designed for automation developers and AI enthusiasts seeking to enhance their knowledge in leveraging the latest intelligent document processing capabilities offered by UiPath.
Speakers:
👨🏫 Andras Palfi, Senior Product Manager, UiPath
👩🏫 Lenka Dulovicova, Product Program Manager, UiPath
JMeter webinar - integration with InfluxDB and GrafanaRTTS
Watch this recorded webinar about real-time monitoring of application performance. See how to integrate Apache JMeter, the open-source leader in performance testing, with InfluxDB, the open-source time-series database, and Grafana, the open-source analytics and visualization application.
In this webinar, we will review the benefits of leveraging InfluxDB and Grafana when executing load tests and demonstrate how these tools are used to visualize performance metrics.
Length: 30 minutes
Session Overview
-------------------------------------------
During this webinar, we will cover the following topics while demonstrating the integrations of JMeter, InfluxDB and Grafana:
- What out-of-the-box solutions are available for real-time monitoring JMeter tests?
- What are the benefits of integrating InfluxDB and Grafana into the load testing stack?
- Which features are provided by Grafana?
- Demonstration of InfluxDB and Grafana using a practice web application
To view the webinar recording, go to:
https://www.rttsweb.com/jmeter-integration-webinar
Connector Corner: Automate dynamic content and events by pushing a buttonDianaGray10
Here is something new! In our next Connector Corner webinar, we will demonstrate how you can use a single workflow to:
Create a campaign using Mailchimp with merge tags/fields
Send an interactive Slack channel message (using buttons)
Have the message received by managers and peers along with a test email for review
But there’s more:
In a second workflow supporting the same use case, you’ll see:
Your campaign sent to target colleagues for approval
If the “Approve” button is clicked, a Jira/Zendesk ticket is created for the marketing design team
But—if the “Reject” button is pushed, colleagues will be alerted via Slack message
Join us to learn more about this new, human-in-the-loop capability, brought to you by Integration Service connectors.
And...
Speakers:
Akshay Agnihotri, Product Manager
Charlie Greenberg, Host
PHP Frameworks: I want to break free (IPC Berlin 2024)Ralf Eggert
In this presentation, we examine the challenges and limitations of relying too heavily on PHP frameworks in web development. We discuss the history of PHP and its frameworks to understand how this dependence has evolved. The focus will be on providing concrete tips and strategies to reduce reliance on these frameworks, based on real-world examples and practical considerations. The goal is to equip developers with the skills and knowledge to create more flexible and future-proof web applications. We'll explore the importance of maintaining autonomy in a rapidly changing tech landscape and how to make informed decisions in PHP development.
This talk is aimed at encouraging a more independent approach to using PHP frameworks, moving towards a more flexible and future-proof approach to PHP development.
Essentials of Automations: Optimizing FME Workflows with ParametersSafe Software
Are you looking to streamline your workflows and boost your projects’ efficiency? Do you find yourself searching for ways to add flexibility and control over your FME workflows? If so, you’re in the right place.
Join us for an insightful dive into the world of FME parameters, a critical element in optimizing workflow efficiency. This webinar marks the beginning of our three-part “Essentials of Automation” series. This first webinar is designed to equip you with the knowledge and skills to utilize parameters effectively: enhancing the flexibility, maintainability, and user control of your FME projects.
Here’s what you’ll gain:
- Essentials of FME Parameters: Understand the pivotal role of parameters, including Reader/Writer, Transformer, User, and FME Flow categories. Discover how they are the key to unlocking automation and optimization within your workflows.
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THERMODYNAMIC ANALYSIS OF ACTUAL
VAPOUR COMPRESSION SYSTEM WITH R22 AND
ITS ECO-FRIENDLY ALTERNATIVES
REFRIGERANTS
Vijay Singh Bisht1
, A.K.Pratihar2
1
Assistant Professor Mechanical Engineering Department, Uttaranchal University,
Dehradun, Uttarakhand, (India)
2
Professor Mechanical Engineering Department, College of Technology G.B.P.U.A.T,
Pantnagar,Uttarakhand (India)
ABSTRACT
This paper presents a theoretical performance study of a vapour compression refrigeration system with
refrigerants R-22, R407C and R410A. A computational model based on energy and exergy analysis is presented
for the investigation of the effects of evaporating temperatures, degree of subcooling, dead state temperatures
and effectiveness of the liquid vapour heat exchanger on the relative capacity change index, coefficient of
performance, exergetic efficiency and exergy destruction ratio of the vapour compression refrigeration cycle.
RCI (relative capacity change index) of the system is highest for R410A and with increase in degree of
subcooling; R410A has the highest percentage increase in COP. Exergetic efficiency of system using R410A is
close to that of R22 system. The optimum temperature range for evaporator for all three refrigerants at which
exergetic efficiency is maximum and EDR is minimum at this condenser temperature 40 ˚C is -30 to -35 ˚C. The
R22 system performance is most affected by pressure drops. At higher degree of subcooling, performance of
R410A improves. Performance of R410A is better than that R407C is evident from the results of thermodynamic
analysis.
Keywords: EDR, Exergetic Efficiency, LVHE, Pressure Drop, RCI.
I INTRODUCTION
Refrigerants are essential working substances used in refrigeration systems. The performance of refrigeration
system largely depends upon the characteristics of the refrigerants. Besides performance issues, there are
environmental issues concerning the use of refrigerants. In last few decades, it was discovered that some
refrigerants cause ozone layer depletion and global warming, which is a serious hazard to environment. Ozone
layer depletion (ODP) and global warming potential (GWP) have become one of the most important global
issues. The Montreal protocol (UNEP, 1997) states the phasing out of CFC’s and HCFC’s as refrigerants that
deplete the ozone layer (ODP). The Kyoto protocol (UNFCC, 2011) encouraged promotion of plans for
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sustainable development and reduction of global warming potential (GWP) including the regulations of HCFCs.
Chlorofluorocarbons (CFCs) are the refrigerants which were responsible for both the environmental problems.
Ozone layer depletion problem has been almost solved by replacing chlorofluorocarbons (CFCs) by hydro
fluorocarbons (HFCs), hydrocarbon (HCs) and some natural refrigerants. However, problem of global warming
is still associated with some newer refrigerants.
R22 refrigerant was mainly used in air conditioners and deep freezers etc. R22 has ozone depletion potential
(ODP) of 0.034. The global warming potential (GWP) of R22 is 1700 and atmospheric life time of 12 years. The
replacements of R22 are R407C and 410A having zero ozone depletion potential. Although, R22 has very low
ozone depletion potential but high global warming potential. The replacements of R22 are R407C and 410A.
The GWP of R407C and R410A are 1600 and 2000 respectively. Since both the refrigerants are blends are
unstable and have negligible atmosphere life time. Therefore, search for better alternatives which have zero
ozone depletion potential (ODP) and zero or lower global warming potential (GWP) and having low
atmospheric life time is still on.
The main characteristics of R22 and its alternative are given in Table 2
Table 2 Characteristics of R22 and Its Alternative Refrigerants [1]
Characteristics R22 R407C R410A
Chemical Formula CHClF2 CH3CHF2 C3F4H2
Molecular weight (g/mol) 120.92 66.05 114.04
Boiling point (˚C ) -40.8 -43.63 -51.36
Ozone Depletion Potential (ODP) 0.034 0 0
Global warming Potential (GWP) 17,80 1700 2000
Safety Group A1 A1 A1
A computational model based on the exergy analysis was presented on vapor compression refrigeration cycle[2].
It was found that the evaporating and condensing temperatures have strong effects on the exergy losses in the
evaporator and condenser and on the second law of efficiency and COP of the cycle but little effects on the
exergy losses in the compressor and the expansion valve. [3] A comparative exergetic analysis on R22 and its
substitution R407C had carried out . The overall exergetic performance of the plant working with R22 was
consistently better than that of its candidate substitute.
Theoretical analysis of vapour compression refrigeration system with R502, R404A and R507A [4]. This study
presented a detailed exergy analysis of an actual vapour compression refrigeration (VCR) cycle. The results
revealed that R507A was better substitute to R502 than R404A. An experimental evaluation of R22 and R407C
evaporative heat transfer coefficients in a vapour compression plant [5]. The experimental conditions under
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which heat transfer coefficients were determined reflect a typical working situation for small l-scale
refrigeration systems. The heat flux ranged from 1.9 to 9.1 kW/m2
and the mass flux was varied from 30 to 140
kg/m2
s. An experimental evaluation is performed on a single-stage vapour compression plant using three
different working fluids, R134a, R407Cand R22. This fact was transferred to the COP, obtaining a smaller value
of the COP using R22 than using R407C for high compression ratios [6]. had presented effect of evaporator
temperature on vapor compression refrigeration system [7]. This study presented comparable evaluation of
R600a (isobutane), R290 (propane), R134a, R22, for R410A, and R32 an optimized finned-tube evaporator, and
analyses the evaporator effect on the system coefficient of performance (COP). From literature review, it
concludes that there is need of thermodynamic analysis of alternative refrigerants to R22. Find out parameters
that enhance system performance while using alternative refrigerants.
II ANALYSIS OF VAPOUR COMPRESSION SYSTEM
The vapour compression system used in present analysis has been shown in figure 2.1.
2.1 Assumptions
Following assumptions have been taken in the analysis:
1. The system is at steady state condition. All processes are steady flow processes.
2. Changes in kinetic and potential energy in analysis of all the components of
system.
3. There is no heat in-leak to the system.
4. Pressure losses in pipelines are neglected.
Figure 2.1 Showing Vapour Compression Systems with Liquid Vapour Heat Exchanger
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Fig.2.2 p-h Diagram of Vapour Compression System with Liquid Vapour Heat Exchanger
2.2 First Law Analysis of Vapour Compression System
(2.1)
Energy balance equation for compressor
(2.2)
= (2.3)
= (2.4)
(2.5)
(2.6)
Energy balance equation for condenser
= (2.7)
Energy balance equation for LVHE
Since the mass flow rate of liquid and vapour is the same, we get from the energy balance of the heat exchanger.
(2.8)
The effectiveness of LVHE is the ratio of the actual to maximum possible heat transfer rates. In our system
effectiveness is given as
= (2.9)
The effect of a liquid-suction heat exchanger on refrigeration capacity can be evaluated in terms of RCI [8].
= ×100 (2.10)
is refrigerating effect, given as
(2.11)
= × (2.12)
Energy balance in expansion valve
(2.13)
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Energy balance equation for evaporator
(2.14)
= (2.15)
Where, is refrigerating capacity, is isentropic efficiency of compressor, is work done by
compressor.
The performance of vapour compression refrigeration system can be predicted in terms of coefficient of
performance (COP),
= (2.16)
2.3 Second Law Analysis of Vapour Compression System
Assuming same assumption as in first law analysis
Exergy balance on a control volume gives
(2.17)
Exergy balance equation for compressor
(2.18)
Exergy destruction in compressor gives
= (2.19)
Exergy balance in condenser gives
= (2.20)
Exergy balance in expansion valve
= (2.21)
Exergy balance in evaporator
= (2.22)
Exergy balance in liquid vapour heat exchanger
= (2.23)
Total exergy destruction in the system is
= (2.24)
The thermal exergy loss in a component is given by
= (2.25)
Where is the heat rejected by the Ith component and TI is the temperature at the boundary of the Ith
component. Thermal exergy loss rate is related to external irreversibility which takes place because of
temperature difference between the control volume and the immediate surroundings.
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Exergetic efficiency: In general case exergetic efficiency is defined as the ratio of exergy recovered to the
exergy supplied.
=
When we apply exergy rate balance in the system then, we get
= + + (2.26)
= the exergy rate at which fuel is supplied, in actual vapour compression system it is equal to compressor
work input .
EP= the exergy rate of product, in case of vapour compression refrigeration system, the product is the exergy of
the heat abstracted in to the evaporator from the space to be cooled at temperature ,
= (2.27)
(2.28)
= (2.29)
Both the equation of exergetic efficiency will give the same result
Exergy destruction ratio (EDR)
EDR is related to exergetic efficiency as shown in equation below:
(2.30)
The present work is validated from the work of Arora and Kaushik, (2008) carried out theoretical analysis of
vapour compression refrigeration system with R502, R404A and R507A.The present computational model
developed for carrying out the energy and exergy analysis of the system using Engineering Equation Solver
software (Klein and Alvarado, 2012). The present computational model system using the same assumptions and
conditions give the same result as by Arora and Kaushik, (2008).
III RESULT AND DISCUSSIONS
A computer program has been developed depending upon the requirements of engineering equation solver
(EES)[9]. The equations are written in the equation window of EES in the FORTRAN LANGUAGE.
Computational model developed for carrying out the energy and exergy analysis of the system using
Engineering Equation Solver software (Klein and Alvarado, 2012) was solved to get the desired results
3.1 Operating conditions assumed for analysis of R22 and its alternatives
For thermodynamic analysis of vapour compression system with R22 and its eco-friendly alternatives following
data is assumed listed below.
The input data assumed is given below:
1. Mass flow rate of refrigerant: 1kg/sec.
2. Degree of sub cooling of liquid refrigerant in LVHE ( ).
3. Isentropic efficiency of compressor ( :75%.
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4. Difference between evaporator and space temperature (TR-Te): 15 .
5. Effectiveness of liquid vapour heat exchanger ε= 0.8.
6. Evaporator temperature -50˚C to 0˚C in steps of 5.
7. Condenser temperature: 40˚C.
8. Pressure drop in evaporator δPe: 20 kPa
9. Pressure drop in condenser δPc 10 kPa.
10. Dead state temperature (T0) = 25 ˚C.
11. It is presumed that pressure drop in liquid vapour heat exchanger (LVHE) is negligible.
3.1.1 Effect of subcooling on relative capacity change index of system with different refrigerants
Fig. 3.1 shows variation in RCI of system with of refrigerants R22, R407C and R410A for different values of
ranging from 1˚ C to 10˚ C.The RCI value is the highest for R410A. R407C has the lowest value at
of 1˚ C and R410A has highest value at 10˚ C.For R410Apercentage change in
refrigerating capacity value is greater than other two refrigerants. Liquid vapour heat exchanger is most
beneficial for R410A.
R
Fig.3.1 Variation of RCI of Refrigerants with Degree of Subcooling
3.1.2 Effect of subcooling on relative capacity change index of system with different refrigerants
For all three refrigerants with increase in evaporator temperature the COP increases as shown in Fig. 3.2. R22
has highest value of COP but the percentage increase in COP value is least among all three refrigerants.
This result trend can be explained from the fact that with increase in evaporator temperature, the pressure ratio
across the compressor reduces causing compressor work to reduce and cooling capacity increases because of
increase in refrigerating effect. The combined effect of these two factors is to enhance the overall COP. R22
gives highest COP among all the refrigerants corresponding to condenser temperatures considered. R410A
shows better COP than R407C at both temperature 50˚C and 40˚C.
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Fig. 3.2 The variation of COP with evaporator temperature at TC = 40˚C
3.1.3 Effect of Liquid Vapour Heat Exchanger Effectiveness on COP of the System
Fig. 3.3 Variation in Value Of COP Of System With Different Refrigerants With Effectiveness
Of LVHE
Fig. 3.3 shows the variation in COP with effectiveness of liquid vapour heat exchanger. For all three
refrigerants, the value of COP decreases with increase in effectiveness of the LVHE. The percentage decrease in
value of COP for R22, R407C and R410A are 15.49%, 15.302% and 18.57 % respectively.
This trend of results can be explained from the fact that with the increase in effectiveness of liquid vapour heat
exchanger, first there is increase in degree of subcooling, consequently specific refrigerating effect increases
causing cooling capacity to increase. Second there is superheating of suction vapour which causes isentropic
compression to happen along the isentropic having reduced slope and thus increase in compressor work is
observed. The positive effect of increase in cooling capacity is heavily negated by increase in compressor work
hence combined effect is such that it causes a decrease in COP of the overall system .
3.1.4 Effect of Evaporator Temperature on exergetic efficiency and EDR of the System
At condenser temperature 40˚C, exergetic efficiency first increases, reaches maximum and then decreases with
increase in evaporator temperature. This trend is based on two parameters; first one is exergy of cooling effect,
i.e. and the other compressor work. At condenser temperature of 40˚C and compressor work
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is dominant over and there is rise in exergetic efficiency at evaporator temperature equal to -30˚C. At
this condenser temperature (40˚C) optimum evaporator temperature range is from -30˚C to -35˚C where
exergetic efficiency is the highest. At the same time since EDR is inversely proportional to exergetic efficiency,
it shows reverse trend. Hence the optimum temperature range for evaporator at this condenser temperature is -30
to -35 ˚C
Fig. 3.4 Effect of Evaporator Temperature on Exergetic Efficiency and EDR of the System.
3.1.5 Effect of dead state temperature on exergetic efficiency and EDR of the system
Fig 3.5 Variation in Exergetic Efficiency And EDR With Dead State Temperature
With increase in dead state temperature, term increases while cooling capacity and compressor work
remain constant and thus exergetic efficiency increases and EDR reduces. This is justified as exergetic
efficiency is inversely proportional to EDR .For a fixed condenser temperature, the increase in dead state
temperature causes the irreversibility (due to finite temperature difference) to decrease and hence EDR reduces
and exergetic efficiency increases. R407C have lower value of exergetic efficiency and higher value of EDR
from both R22 and 410A.
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3.1.6 The variation in exergetic efficiency of the system with effectiveness of liquid vapour heat
exchanger.
Fig. 3.6 shows the variation in exergetic efficiency of the system with effectiveness of liquid vapour heat
exchanger. For all three refrigerants, the value of ergetic efficiency for system decreases with increase in
effectiveness of the liquid vapour heat exchanger.
This trend of results can be explained from the fact that with the increase in effectiveness of liquid-vapour heat
exchanger, first there is increase in degree of subcooling, consequently specific refrigerating effect increases
causing cooling capacity to increase, second there is superheating of suction vapour which causes isentropic
compression to happen along the isentropes having reduced slope and thus increase in compressor work is
observed. The positive effect of increase in cooling capacity is heavily negated by increase in compressor work.
Fig. 3.6 Variation in Exergetic Efficiency of the System with Effectiveness of Liquid Vapour
Heat Exchanger
The cooling effect also has slightly increased in its value, because has no effect of
effectiveness, and remain constant. The exergetic efficiency by ratio of cooling effect divides by compressor
work of the system. The denominator term has large increase in value than the numerator term
when the effectiveness of the LVHE is increases, hence exergetic efficiency decrease. At the same time since
EDR is inversely proportional to exergetic efficiency, it increases with effectiveness.
3.1.6 Variation in the exergetic efficiency of the system with and without pressure drops in the evaporator
and condenser
Fig. 3.7 shows the variation in exergetic efficiency of system with and without pressure drops in evaporator and
condenser. R22 is the most affected by pressure drops. The percentage decrease in value of exergetic efficiency
is the highest for R22 (4.037%). R410A is the least effected by pressure drops. The percentage decrease in
value of exergetic efficiency is the lowest for R410A (2.47%).
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Fig 3.7 Variation in the Exergetic Efficiency of the System with and Without Pressure Drops In
the Evaporator and Condenser
IV CONCLUSION
1. The COP of system is the highest for R22.In the descending order of COP v these refrigerants can be
arranged as R22, R410A and R407C. The RCI value is the highest for R410A at evaporator
temperature 0˚C. In the descending order of RCI these refrigerants can be arranged as R410A, R407C
and R22. It is concluded that LVHE is most beneficial for R410A.
2. At fixed condenser temperature of 40˚C, evaporator temperature has been varied from -50˚C to 0˚C.
All three refrigerants show highest value of exergetic efficiency of system individually, at evaporator
temperature ranging from -35 to -30˚C. It is concluded that this range is the optimum evaporator
temperature range for system while using these refrigerants. The exergetic efficiency of system for R22
is the highest. The EDR value is the lowest at optimum evaporator temperature range. In the
descending order of exergetic efficiency these refrigerants can be arranged as R22, R410A and R407C.
3. The increase in dead state temperature has positive effect on the exergetic efficiency of system. R22 shows
higher value of exergetic efficiency than R410A and R407C. R407C has lowest value of exergetic efficiency of
all three refrigerants.
4. Performance of R22 is the most affected by pressure drops in evaporator and condenser.
It is concluded that performance wise R407C and R410A performance are poorer than R22. But at after higher
degree of subcooling, performance of R410A improves. Performance of R410A is better than that R407C as
evident from the results of thermodynamic analysis is based on both first and second law of thermodynamics.
REFERENCES
[1] Calm.J.M and Domanski.P.A . R22 replacement. ASHARE Journal.2004. 46(8): 29-39
[2 ] Yumrutas .R., Kunduz, M and Kanoglu, M.. Exergy analysis of vapor compression refrigeration systems. Journal of
Exergy. 2002. 2:266-272.
[3] Greco, A. and Aprea, C. An exergetic analysis of R22 substitution. International journal of applied thermal engineering.
2002. 22 1455–1469.
12. International Journal of Advance Research In Science And Engineering http://www.ijarse.com
IJARSE, Vol. No.3, Issue No.3, March 2014 ISSN-2319-8354(E)
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[4] Arora, A. and Kaushik, S.C. Theoretical analysis of a vapour compression refrigeration system with R502, R404
and R507A. International journal of refrigeration. 2008 . 31: 998 – 1005.
[5] Aprea, C., Rossi. F. and Greco, A. Experimental evaluation of R22 and R407C evaporative heat transfer coefficients in
a vapour compression plant International journal of refrigeration.2000..23:366-377.
[6] Esbrı, J. N.,Cabello.R. and Torrella, E.. Experimental evaluation of a vapour compression plant performance using
R134a, R407C and R22 as working fluids. Applied Thermal Engineering. .2004. 24:1905–1917.
[7] Abdullah, Al. Effect of evaporator temperature on vapor compression refrigeration system. Alexandria engineering
journal. . 2012. 50: 283–290
[8] Klein, S.A.. Engineering Equation Solver. Version 2012. V9.205 3-D. F Chart Software.
[9] Klein. S. A., Reindl, D.T. and Brownell, K.. Refrigeration system performance using liquid-suction heat exchangers.
International Journal of Refrigeration. 2000. 23: 588-596.