This document analyzes the thermodynamic performance of an ejector refrigeration cycle using various eco-friendly refrigerants (R-404A, R-410A, R-407C, etc.). It presents results from a numerical simulation that varied the boiler, condenser, and evaporator temperatures. The simulation found that R-404A achieved the highest COP and second law efficiency in many temperature ranges. R-410A achieved the highest refrigeration effect for all temperature ranges. In general, R-410A and R-404A performed best among the refrigerants analyzed, with R-410A having the best refrigeration effect and R-404A having the best COP and second law efficiency.
This document describes an ejector-expansion refrigeration system (EERS). It discusses the components and working of the EERS cycle including the compressor, condenser, ejector, separator, expansion valve and evaporator. It also describes the constant area ejector and working of the ejector. The document analyzes the system performance based on conservation equations and discusses the effects of evaporation and condensation temperatures on performance parameters like COP, compressor power and pressure ratio. It concludes that COP increases with evaporation temperature but decreases with condensation temperature.
An ejector refrigeration cycle powered by an internal combustion engine. it is a ppt for presentation, including introduction, working principle, performance of an ejector refrigeration.
.
Refrigeration forms the basic essence of living comfort. Ejector Expansion Refrigeration Cycle (EERC) is a not so commonly used method of refrigeration. The use of this method is quite understated. It increases the efficiency of the normal refrigeration cycle by almost 16% over the basic cycle by utilising the energy wasted otherwise in the expansion valve in form of expansion process losses. EERC system has high potential which if harnessed properly could prove to be a very efficient method of refrigeration. This paper aims to showcase the real features of this method in a hope that it finds its way out in the commercial industry today.
The document outlines the objectives and methodology for a project to analyze and develop a compact vapor jet refrigeration system. The key objectives are to optimize the ejector design using single and multiple swirls, provide a full opening around the primary nozzle, analyze performance with new working fluids, design and test a 1 TR refrigeration system, and conduct experiments. The methodology involves theoretical analysis, designing and fabricating system components, flow visualization studies on the ejector, experimentation on the ejector and system, and performance analysis. The work is split into common elements and technical elements related to the ejector and system design.
cfd analysis on ejector cooling system with variable throat geometryIjripublishers Ijri
The vapor jet ejector cooling cycle driven by waste heat. It is a very auspicious approach of producing ‘free cooling’ by utilizing low-grade energy sources. The mechanism behind the ejector-based on waste heat cooling is very unique, when compared to absorption or adsorption cooling technologies. They are also aimed at producing heat driven cooling. This type of ejector cooling system is actually more closely related to vapor compression technology.
In this paper simulations of a vapor-jet ejector operating with refregerent R134a as the working fluid by using CFD (computational fluid dynamics). The impact of varying geometry parameters on ejector performance will be considered. Different mixing section radii will be considered for the analysis.
3D modeling is done by using Catia V5 and analysis is done by Ansys fluent14.5.
The document discusses an ejector refrigeration system (ERS). An ERS uses an ejector instead of a compressor to increase fluid pressure without moving parts. The ejector consists of a primary nozzle, mixing chamber, ejector throat, and diffuser. High pressure fluid expands through the primary nozzle, drawing and mixing with low pressure secondary fluid in the mixing chamber. The document reviews several theories for modeling ejector performance and past studies analyzing ejector design and refrigeration cycle optimization. It also discusses design parameters like entrainment ratio and operating modes like critical and subcritical.
A solar ejector cooling system using refrigerant r141bMark Murray
This document describes a solar ejector cooling system that uses R141b as the working fluid. Key points:
- The system achieves a high coefficient of performance (COP) of 0.5 experimentally for single-stage cooling at a generation temperature of 90°C, condensing temperature of 28°C, and evaporating temperature of 8°C.
- For solar cooling, the overall COP is estimated to be around 0.22 at a generation temperature of 95°C, evaporating temperature of 8°C, and solar radiation of 700 W/m2.
- The solar ejector cooling system is simpler than absorption cooling systems and has potential for solar refrigeration applications with an optimum overall
IRJET- Design and Analysis of Ejector Refrigeration System using R-134a Refr...IRJET Journal
This document summarizes the design and analysis of an ejector refrigeration system using R-134a refrigerant. It presents the schematic and thermodynamic processes of the system. Dimensions of the ejector components like the nozzle, mixing section, and diffuser are specified based on analytical calculations. The COP is calculated to be 1.105 for R-134a. Effects of varying generator temperature, condenser temperature, area ratio of the ejector, back pressure, and length of the mixing section on the entrainment ratio and COP are analyzed. CFD modeling is used to simulate the ejector and observe pressure and velocity variations.
This document describes an ejector-expansion refrigeration system (EERS). It discusses the components and working of the EERS cycle including the compressor, condenser, ejector, separator, expansion valve and evaporator. It also describes the constant area ejector and working of the ejector. The document analyzes the system performance based on conservation equations and discusses the effects of evaporation and condensation temperatures on performance parameters like COP, compressor power and pressure ratio. It concludes that COP increases with evaporation temperature but decreases with condensation temperature.
An ejector refrigeration cycle powered by an internal combustion engine. it is a ppt for presentation, including introduction, working principle, performance of an ejector refrigeration.
.
Refrigeration forms the basic essence of living comfort. Ejector Expansion Refrigeration Cycle (EERC) is a not so commonly used method of refrigeration. The use of this method is quite understated. It increases the efficiency of the normal refrigeration cycle by almost 16% over the basic cycle by utilising the energy wasted otherwise in the expansion valve in form of expansion process losses. EERC system has high potential which if harnessed properly could prove to be a very efficient method of refrigeration. This paper aims to showcase the real features of this method in a hope that it finds its way out in the commercial industry today.
The document outlines the objectives and methodology for a project to analyze and develop a compact vapor jet refrigeration system. The key objectives are to optimize the ejector design using single and multiple swirls, provide a full opening around the primary nozzle, analyze performance with new working fluids, design and test a 1 TR refrigeration system, and conduct experiments. The methodology involves theoretical analysis, designing and fabricating system components, flow visualization studies on the ejector, experimentation on the ejector and system, and performance analysis. The work is split into common elements and technical elements related to the ejector and system design.
cfd analysis on ejector cooling system with variable throat geometryIjripublishers Ijri
The vapor jet ejector cooling cycle driven by waste heat. It is a very auspicious approach of producing ‘free cooling’ by utilizing low-grade energy sources. The mechanism behind the ejector-based on waste heat cooling is very unique, when compared to absorption or adsorption cooling technologies. They are also aimed at producing heat driven cooling. This type of ejector cooling system is actually more closely related to vapor compression technology.
In this paper simulations of a vapor-jet ejector operating with refregerent R134a as the working fluid by using CFD (computational fluid dynamics). The impact of varying geometry parameters on ejector performance will be considered. Different mixing section radii will be considered for the analysis.
3D modeling is done by using Catia V5 and analysis is done by Ansys fluent14.5.
The document discusses an ejector refrigeration system (ERS). An ERS uses an ejector instead of a compressor to increase fluid pressure without moving parts. The ejector consists of a primary nozzle, mixing chamber, ejector throat, and diffuser. High pressure fluid expands through the primary nozzle, drawing and mixing with low pressure secondary fluid in the mixing chamber. The document reviews several theories for modeling ejector performance and past studies analyzing ejector design and refrigeration cycle optimization. It also discusses design parameters like entrainment ratio and operating modes like critical and subcritical.
A solar ejector cooling system using refrigerant r141bMark Murray
This document describes a solar ejector cooling system that uses R141b as the working fluid. Key points:
- The system achieves a high coefficient of performance (COP) of 0.5 experimentally for single-stage cooling at a generation temperature of 90°C, condensing temperature of 28°C, and evaporating temperature of 8°C.
- For solar cooling, the overall COP is estimated to be around 0.22 at a generation temperature of 95°C, evaporating temperature of 8°C, and solar radiation of 700 W/m2.
- The solar ejector cooling system is simpler than absorption cooling systems and has potential for solar refrigeration applications with an optimum overall
IRJET- Design and Analysis of Ejector Refrigeration System using R-134a Refr...IRJET Journal
This document summarizes the design and analysis of an ejector refrigeration system using R-134a refrigerant. It presents the schematic and thermodynamic processes of the system. Dimensions of the ejector components like the nozzle, mixing section, and diffuser are specified based on analytical calculations. The COP is calculated to be 1.105 for R-134a. Effects of varying generator temperature, condenser temperature, area ratio of the ejector, back pressure, and length of the mixing section on the entrainment ratio and COP are analyzed. CFD modeling is used to simulate the ejector and observe pressure and velocity variations.
STEAM JET COOLING SYSTEM
Steam jet cooling system is a cooling technique which involves usage of steam and water for cooling purposes. In steam jet refrigeration systems, water can be used as the refrigerant. Like air, it is perfectly safe. These systems were applied successfully to refrigeration.
•Temperatures attained using water as a refrigerant are in the range which may satisfy air conditioning, cooling, or chilling requirements.
•Mostly low-grade energy and relatively small amounts of shaft work.
•This system are the utilization of mostly low-grade energy and relatively small amounts of shaft work.
•Not used when temperatures below 5°C are required.
The document discusses Heat Recovery Steam Generators (HRSGs). HRSGs recover heat from gas turbine exhaust to produce steam. They operate in either combined cycle mode, where steam drives a turbine, or cogeneration mode where steam is used for industrial processes. HRSGs contain evaporator, economizer, and superheater sections to produce steam. They can also include reheaters, deaerators, and preheaters. HRSGs come in natural circulation, forced circulation, or once-through designs and can be unfired, fired, supplementary fired, or exhaust fired depending on heat input. HRSGs vary in operation pressure as either single or multi-pressure. Post-combustion emission controls like
La recupercion de Energia termica que eliminan los gases de escape a la atmotfera de las turbinas o generadores de combustion interna. Pueden ser aprovechadas para producir vapor de media presion y ser utilizadas en la industria. La cogeneracion es una importante alternativa para generar grandes ahorros de combustible. Te invito a investigar y tomar las mejores decisiones para tus proyectos de ahorro energetico.
1) An injector, also known as an ejector or steam injector, is a type of pump that uses the Venturi effect to pump fluids without moving parts.
2) Originally used on steam locomotives to inject boiler feedwater, injectors work by converting the pressure energy of a high-pressure motive fluid like steam into velocity energy, creating a low pressure zone that draws in and mixes with a suction fluid.
3) Modern uses of injectors include pumping chemicals into boilers, removing ash from power plant flues, producing vacuum pressure, and enhancing oil recovery processes. They are commonly used in well pumps where the jet pump is installed below ground.
The document discusses refrigeration systems used in aircraft. It describes several types of air refrigeration systems:
1) Simple systems use compressed air cooled by a turbine-driven fan for ground cooling.
2) Bootstrap systems add a secondary compressor driven by the turbine to increase cooling capacity for high-speed aircraft.
3) Regenerative systems further cool air in a secondary heat exchanger using bled refrigerated air.
4) Reduced ambient systems use two turbines, one for cabin air and one for cooling air, driven by a single fan to cool air below ambient temperatures for supersonic aircraft.
The document is a project report submitted by five students for their Bachelor of Technology degree in Mechanical Engineering. It details the design, construction and testing of a refrigeration system that uses waste heat from an internal combustion engine as its energy source, instead of electrical power. The system employs an Electrolux vapor absorption refrigeration cycle, which is suitable for operating on low-grade heat. Diagrams and descriptions of the key components, such as the compressor, condenser and evaporator, are provided. The report also includes photographs documenting the building process.
STUDY OF CONDENSER AND ITS DIFFERENT TYPESAziz Rehman
This study examines different types of condensers used in refrigerants. It discusses air cooled and water cooled condensers. Air cooled condensers can use natural or forced convection, while water cooled condensers include tube-in-tube, shell-and-coil, and shell-and-tube designs. The study tests different materials for condensers, finding that copper has the highest thermal conductivity and best heat transfer, followed by aluminum and steel. The objective is to select the best material for a condenser by considering factors like thermal conductivity and heat transfer performance.
This document provides operating procedures for a heat recovery steam generator (HRSG) unit, including:
1) Pre-operating procedures such as cleaning, chemical cleaning, blowing steam lines, setting safety valves, and filling the unit before cold startup.
2) Cold startup procedures such as adjusting water levels, purging the unit, gradually warming it up and introducing supplementary firing.
3) Guidelines for normal shutdown including stopping supplementary firing and slowly reducing gas flow and pressure.
4) Emergency procedures for low or high water levels and tube failures.
5) A walkdown checklist to inspect for leaks or abnormal conditions.
The document discusses condensers used in thermal power plants. It describes the functions of a condenser as condensing exhaust steam from turbines to be reused in the steam cycle, creating a vacuum to improve turbine efficiency, and removing non-condensable gases. Key aspects covered include the condenser's role in the Rankine cycle, operation, materials used for tubes, sources of air leakage, methods for detecting water leakage into tubes, and cleaning and testing of condenser tubes.
Design and Fabrication of Vapour Absorption Refrigeration System [Libr-H20]IJMER
Most of the energies are utilized by the industries due to depletion of fossil fuels and
increasing the fuel price to exploit the maximum presented energy from the waste heat source. The
industry which utilizes steam turbine exhaust carries a considerable amount of thermal energy. This
energy can be set in to positive use as a heat source for vapour absorption system to serves as cooling
system. This paper illustrates the thermal and fiscal advantages of using single effect lithium bromide
water absorption by means of waste heat. The objective of this work is to hypothetical design of lithium
bromide water absorption Refrigeration system using waste heat from any industry steam turbine
exhaust
The document discusses heat recovery steam generators (HRSGs). It provides the following key points:
1) HRSGs consist of four main components - economizer, evaporator, superheater, and water preheater - to convert heat from exhaust gases into steam.
2) HRSGs can be categorized as horizontal or vertical based on exhaust gas flow direction, and single pressure or multi-pressure based on number of steam drums.
3) Packaged HRSGs are pre-assembled units suitable for waste heat or small turbine applications under 20MW. They can include supplemental firing for higher efficiency.
Cooling of a truck cabin by vapour absorption refrigeration system using engi...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
The document presents information on a bootstrap air cooling system suitable for aircraft. It consists of two heat exchangers, a secondary compressor driven by a turbine, and uses ram air and compression to cool and circulate air. Ambient air is compressed by the main aircraft compressor then cooled in an air cooler before further compression and cooling. It is then expanded through a turbine to provide cooled air to the aircraft cabin. Advantages are that air is readily available, non-toxic, and pressures are low. A limitation is that it requires aircraft flight for ram air cooling and is not suitable for ground use without an additional fan.
The document discusses steam nozzles, which are passages used to convert the potential energy of steam into kinetic energy by increasing steam velocity. It describes the key types of nozzles - convergent, divergent, and convergent-divergent - and their uses depending on back pressure conditions. The document also outlines course objectives and outcomes for a Thermal Engineering II class focusing on applying thermodynamic concepts to nozzles, boilers, turbines, and refrigeration/air conditioning systems.
Hrsg & turbine as run energy efficiency assessmentD.Pawan Kumar
The document provides measurements and performance data from an assessment of a heat recovery steam generator (HRSG) and steam turbine system. Key findings include:
- The HRSG achieved an overall thermal efficiency of 84.43% based on measured temperature and flow data.
- Heat was recovered across multiple components, with the high pressure evaporator recovering the most at 41.95% of total heat.
- The steam turbine achieved an overall efficiency of 78.40% based on measured steam and electrical output values.
Development of vapour absorption refrigeration system in vehiclesAshish Singh
This document discusses the development of a vapor absorption refrigeration system for use in vehicles. It begins with an introduction that explains vapor absorption and vapor compression refrigeration systems. The objectives are to lower the vehicle's temperature using waste heat from the engine. Literature on previous related projects is reviewed. The proposed system would use a generator heated by exhaust gases to power the vapor absorption cycle. Performance is analyzed considering temperatures and heat transfer. Components are specified and costs are estimated. A timeline is provided. The vapor absorption system could utilize otherwise wasted engine heat to provide cooling, reducing fuel costs compared to vapor compression.
The document discusses heat recovery steam generators (HRSGs). An HRSG uses heat from hot exhaust gases to generate steam. It is composed of an economizer, evaporator, and superheater. The hot exhaust gases pass through these components, reducing in temperature while heating water and generating high-pressure steam. The steam can then be used to drive a steam turbine. The document discusses the components, types, circulation methods, heating surfaces, and other aspects of HRSG design and operation.
The document describes the design and fabrication of a single-effect vapor absorption refrigeration system using LiBr-H2O and exhaust heat. The system was designed to (1) be environmentally friendly by using waste heat, (2) have low running costs, and (3) meet energy demands sustainably. A car was used as the environment where the cooling load was estimated. Components like the generator, condenser, evaporator, and absorber were modeled in ASPEN and tested experimentally using exhaust from an electric generator and LPG. The system was able to lower the chamber temperature by 4-5°C and had a COP of 0.0012-0.0013 without including heat input.
The document discusses the history and principles of vapor absorption refrigeration systems. Some key points:
- Vapor absorption was first discovered in 1824 by Michael Faraday and the first machine was built in 1860. It uses a refrigerant (ammonia) that is absorbed into a solvent (water) for compression.
- Unlike vapor compression, it uses heat rather than mechanical energy to change the refrigerant's state. This allows it to be powered by waste heat or solar energy.
- The first domestic refrigerator using this technology was invented in 1925 and used ammonia, hydrogen, and water in a "three-fluid" system to eliminate the need for a pump.
Ijri te-03-010 cfd analysis on ejector cooling system with variable throat ge...Ijripublishers Ijri
This document discusses CFD analysis of an ejector cooling system with variable throat geometry. It begins with background on ejector working principles and prior literature. It then describes the design and meshing of three ejector models in CATIA and Ansys. CFD analysis is performed on the original and two modified ejector designs with R134a as the working fluid. Results for velocity, pressure, temperature, shear stress, kinetic energy, density, and mass flow rate are presented in table and graph form. The modified design with a 3mm throat diameter performed best with lowest stress and highest mass flow rate. Future work could analyze different mixing section lengths, nozzle radii, and working fluids to further increase efficiency.
IRJET- A Review on Developing a Model that Uses Waste Heat from Condenser in ...IRJET Journal
This document reviews several studies on developing models to utilize waste heat from the condenser in a vapor compression refrigeration cycle. Key findings from the studies include:
1) Models that recover waste heat from the condenser can increase the COP of the vapor compression system by 10-11%.
2) Waste heat recovered from the condenser has been used to heat water, operate an oven, power additional refrigeration cycles, and improve the efficiency of air conditioning systems.
3) Optimal operating parameters like temperatures and fluid flow rates need to be considered to feasibly recover waste heat from the condenser.
IRJET- Thermodynamic Performance Comparison between Ethylene and Ethane in Tr...IRJET Journal
The document compares the thermodynamic performance of ethane and ethylene as refrigerants in transcritical refrigeration cycles with and without an internal heat exchanger. Equations for energy and exergy analysis are presented. Results show that when using ethane, both the basic transcritical cycle and cycle with an internal heat exchanger have higher COP, lower optimum discharge pressure, and higher second law efficiency compared to ethylene. Therefore, the study finds that using ethane in a basic transcritical cycle with an internal heat exchanger is preferable.
STEAM JET COOLING SYSTEM
Steam jet cooling system is a cooling technique which involves usage of steam and water for cooling purposes. In steam jet refrigeration systems, water can be used as the refrigerant. Like air, it is perfectly safe. These systems were applied successfully to refrigeration.
•Temperatures attained using water as a refrigerant are in the range which may satisfy air conditioning, cooling, or chilling requirements.
•Mostly low-grade energy and relatively small amounts of shaft work.
•This system are the utilization of mostly low-grade energy and relatively small amounts of shaft work.
•Not used when temperatures below 5°C are required.
The document discusses Heat Recovery Steam Generators (HRSGs). HRSGs recover heat from gas turbine exhaust to produce steam. They operate in either combined cycle mode, where steam drives a turbine, or cogeneration mode where steam is used for industrial processes. HRSGs contain evaporator, economizer, and superheater sections to produce steam. They can also include reheaters, deaerators, and preheaters. HRSGs come in natural circulation, forced circulation, or once-through designs and can be unfired, fired, supplementary fired, or exhaust fired depending on heat input. HRSGs vary in operation pressure as either single or multi-pressure. Post-combustion emission controls like
La recupercion de Energia termica que eliminan los gases de escape a la atmotfera de las turbinas o generadores de combustion interna. Pueden ser aprovechadas para producir vapor de media presion y ser utilizadas en la industria. La cogeneracion es una importante alternativa para generar grandes ahorros de combustible. Te invito a investigar y tomar las mejores decisiones para tus proyectos de ahorro energetico.
1) An injector, also known as an ejector or steam injector, is a type of pump that uses the Venturi effect to pump fluids without moving parts.
2) Originally used on steam locomotives to inject boiler feedwater, injectors work by converting the pressure energy of a high-pressure motive fluid like steam into velocity energy, creating a low pressure zone that draws in and mixes with a suction fluid.
3) Modern uses of injectors include pumping chemicals into boilers, removing ash from power plant flues, producing vacuum pressure, and enhancing oil recovery processes. They are commonly used in well pumps where the jet pump is installed below ground.
The document discusses refrigeration systems used in aircraft. It describes several types of air refrigeration systems:
1) Simple systems use compressed air cooled by a turbine-driven fan for ground cooling.
2) Bootstrap systems add a secondary compressor driven by the turbine to increase cooling capacity for high-speed aircraft.
3) Regenerative systems further cool air in a secondary heat exchanger using bled refrigerated air.
4) Reduced ambient systems use two turbines, one for cabin air and one for cooling air, driven by a single fan to cool air below ambient temperatures for supersonic aircraft.
The document is a project report submitted by five students for their Bachelor of Technology degree in Mechanical Engineering. It details the design, construction and testing of a refrigeration system that uses waste heat from an internal combustion engine as its energy source, instead of electrical power. The system employs an Electrolux vapor absorption refrigeration cycle, which is suitable for operating on low-grade heat. Diagrams and descriptions of the key components, such as the compressor, condenser and evaporator, are provided. The report also includes photographs documenting the building process.
STUDY OF CONDENSER AND ITS DIFFERENT TYPESAziz Rehman
This study examines different types of condensers used in refrigerants. It discusses air cooled and water cooled condensers. Air cooled condensers can use natural or forced convection, while water cooled condensers include tube-in-tube, shell-and-coil, and shell-and-tube designs. The study tests different materials for condensers, finding that copper has the highest thermal conductivity and best heat transfer, followed by aluminum and steel. The objective is to select the best material for a condenser by considering factors like thermal conductivity and heat transfer performance.
This document provides operating procedures for a heat recovery steam generator (HRSG) unit, including:
1) Pre-operating procedures such as cleaning, chemical cleaning, blowing steam lines, setting safety valves, and filling the unit before cold startup.
2) Cold startup procedures such as adjusting water levels, purging the unit, gradually warming it up and introducing supplementary firing.
3) Guidelines for normal shutdown including stopping supplementary firing and slowly reducing gas flow and pressure.
4) Emergency procedures for low or high water levels and tube failures.
5) A walkdown checklist to inspect for leaks or abnormal conditions.
The document discusses condensers used in thermal power plants. It describes the functions of a condenser as condensing exhaust steam from turbines to be reused in the steam cycle, creating a vacuum to improve turbine efficiency, and removing non-condensable gases. Key aspects covered include the condenser's role in the Rankine cycle, operation, materials used for tubes, sources of air leakage, methods for detecting water leakage into tubes, and cleaning and testing of condenser tubes.
Design and Fabrication of Vapour Absorption Refrigeration System [Libr-H20]IJMER
Most of the energies are utilized by the industries due to depletion of fossil fuels and
increasing the fuel price to exploit the maximum presented energy from the waste heat source. The
industry which utilizes steam turbine exhaust carries a considerable amount of thermal energy. This
energy can be set in to positive use as a heat source for vapour absorption system to serves as cooling
system. This paper illustrates the thermal and fiscal advantages of using single effect lithium bromide
water absorption by means of waste heat. The objective of this work is to hypothetical design of lithium
bromide water absorption Refrigeration system using waste heat from any industry steam turbine
exhaust
The document discusses heat recovery steam generators (HRSGs). It provides the following key points:
1) HRSGs consist of four main components - economizer, evaporator, superheater, and water preheater - to convert heat from exhaust gases into steam.
2) HRSGs can be categorized as horizontal or vertical based on exhaust gas flow direction, and single pressure or multi-pressure based on number of steam drums.
3) Packaged HRSGs are pre-assembled units suitable for waste heat or small turbine applications under 20MW. They can include supplemental firing for higher efficiency.
Cooling of a truck cabin by vapour absorption refrigeration system using engi...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
The document presents information on a bootstrap air cooling system suitable for aircraft. It consists of two heat exchangers, a secondary compressor driven by a turbine, and uses ram air and compression to cool and circulate air. Ambient air is compressed by the main aircraft compressor then cooled in an air cooler before further compression and cooling. It is then expanded through a turbine to provide cooled air to the aircraft cabin. Advantages are that air is readily available, non-toxic, and pressures are low. A limitation is that it requires aircraft flight for ram air cooling and is not suitable for ground use without an additional fan.
The document discusses steam nozzles, which are passages used to convert the potential energy of steam into kinetic energy by increasing steam velocity. It describes the key types of nozzles - convergent, divergent, and convergent-divergent - and their uses depending on back pressure conditions. The document also outlines course objectives and outcomes for a Thermal Engineering II class focusing on applying thermodynamic concepts to nozzles, boilers, turbines, and refrigeration/air conditioning systems.
Hrsg & turbine as run energy efficiency assessmentD.Pawan Kumar
The document provides measurements and performance data from an assessment of a heat recovery steam generator (HRSG) and steam turbine system. Key findings include:
- The HRSG achieved an overall thermal efficiency of 84.43% based on measured temperature and flow data.
- Heat was recovered across multiple components, with the high pressure evaporator recovering the most at 41.95% of total heat.
- The steam turbine achieved an overall efficiency of 78.40% based on measured steam and electrical output values.
Development of vapour absorption refrigeration system in vehiclesAshish Singh
This document discusses the development of a vapor absorption refrigeration system for use in vehicles. It begins with an introduction that explains vapor absorption and vapor compression refrigeration systems. The objectives are to lower the vehicle's temperature using waste heat from the engine. Literature on previous related projects is reviewed. The proposed system would use a generator heated by exhaust gases to power the vapor absorption cycle. Performance is analyzed considering temperatures and heat transfer. Components are specified and costs are estimated. A timeline is provided. The vapor absorption system could utilize otherwise wasted engine heat to provide cooling, reducing fuel costs compared to vapor compression.
The document discusses heat recovery steam generators (HRSGs). An HRSG uses heat from hot exhaust gases to generate steam. It is composed of an economizer, evaporator, and superheater. The hot exhaust gases pass through these components, reducing in temperature while heating water and generating high-pressure steam. The steam can then be used to drive a steam turbine. The document discusses the components, types, circulation methods, heating surfaces, and other aspects of HRSG design and operation.
The document describes the design and fabrication of a single-effect vapor absorption refrigeration system using LiBr-H2O and exhaust heat. The system was designed to (1) be environmentally friendly by using waste heat, (2) have low running costs, and (3) meet energy demands sustainably. A car was used as the environment where the cooling load was estimated. Components like the generator, condenser, evaporator, and absorber were modeled in ASPEN and tested experimentally using exhaust from an electric generator and LPG. The system was able to lower the chamber temperature by 4-5°C and had a COP of 0.0012-0.0013 without including heat input.
The document discusses the history and principles of vapor absorption refrigeration systems. Some key points:
- Vapor absorption was first discovered in 1824 by Michael Faraday and the first machine was built in 1860. It uses a refrigerant (ammonia) that is absorbed into a solvent (water) for compression.
- Unlike vapor compression, it uses heat rather than mechanical energy to change the refrigerant's state. This allows it to be powered by waste heat or solar energy.
- The first domestic refrigerator using this technology was invented in 1925 and used ammonia, hydrogen, and water in a "three-fluid" system to eliminate the need for a pump.
Ijri te-03-010 cfd analysis on ejector cooling system with variable throat ge...Ijripublishers Ijri
This document discusses CFD analysis of an ejector cooling system with variable throat geometry. It begins with background on ejector working principles and prior literature. It then describes the design and meshing of three ejector models in CATIA and Ansys. CFD analysis is performed on the original and two modified ejector designs with R134a as the working fluid. Results for velocity, pressure, temperature, shear stress, kinetic energy, density, and mass flow rate are presented in table and graph form. The modified design with a 3mm throat diameter performed best with lowest stress and highest mass flow rate. Future work could analyze different mixing section lengths, nozzle radii, and working fluids to further increase efficiency.
IRJET- A Review on Developing a Model that Uses Waste Heat from Condenser in ...IRJET Journal
This document reviews several studies on developing models to utilize waste heat from the condenser in a vapor compression refrigeration cycle. Key findings from the studies include:
1) Models that recover waste heat from the condenser can increase the COP of the vapor compression system by 10-11%.
2) Waste heat recovered from the condenser has been used to heat water, operate an oven, power additional refrigeration cycles, and improve the efficiency of air conditioning systems.
3) Optimal operating parameters like temperatures and fluid flow rates need to be considered to feasibly recover waste heat from the condenser.
IRJET- Thermodynamic Performance Comparison between Ethylene and Ethane in Tr...IRJET Journal
The document compares the thermodynamic performance of ethane and ethylene as refrigerants in transcritical refrigeration cycles with and without an internal heat exchanger. Equations for energy and exergy analysis are presented. Results show that when using ethane, both the basic transcritical cycle and cycle with an internal heat exchanger have higher COP, lower optimum discharge pressure, and higher second law efficiency compared to ethylene. Therefore, the study finds that using ethane in a basic transcritical cycle with an internal heat exchanger is preferable.
IRJET- Design and Development of a Waste Heat Recovery Unit for Household Ref...IRJET Journal
The document describes a study to design and develop a waste heat recovery unit for a household refrigerator system. The researchers designed a new water-cooled condenser to replace the original air-cooled condenser. They integrated the new condenser with a waste heat recovery unit placed behind the refrigerator. Testing found that the water in the recovery unit could reach temperatures of around 50°C after 3 hours, with an average of 40°C. The new system did not significantly affect refrigerator performance while improving the overall efficiency by recovering waste heat.
Design of waste heat driven vapour adsorption cooling system for vehicle air ...eSAT Journals
Abstract In this present era more & more focus is to be given on energy conservation. Refrigeration & air conditioning is one of the growing field of engineering, the existing system are hampering the environment as they are suffering from various environmental problems such as depletion of ozone layer & global warming due to emission of harmful gases such as HFC’s ,CFC’s & CO2 as they were using traditional refrigerants. Waste heat driven Vapour adsorption cooling system is eco-friendly, efficient, & reliable in nature. But on the other hand this system having lowers COP as compare to existing systems which is Due to the lack of research and advancement in the system. By considering the environmental aspects & need of energy conservation it is necessary to design and developed the VAR’s system which will successfully compete the existing systems. This paper will give the idea about the Design of waste heat driven vapour adsorption system of 2KW capacity for vehicle air-conditioning & refrigeration application. The adsorber bed is the heart of the cooling system and it can affect the performance of the system to the greater extent. So that while designing the VAR cooling system more focused is given on design and selection of adsorber bed. This article mainly focused on the various and important design parameters of the vapour adsorption cooling system Such as Adsorber bed design, adsorber and adsorbate mass, design of evaporator & condenser, Coefficient of performance(COP), Specific cooling power (SCP) and the other performance affecting parameters. Keywords: Vapour Adsorption, Design Parameters, Low Grade Thermal Energy, Adsorbate & Adsorbent.
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.
IRJET-Numerical Investigation on Performance of VCR System using Shell and Tu...IRJET Journal
This document discusses numerically investigating the performance of a vapor compression refrigeration (VCR) system using different types of heat exchangers. It aims to replace an existing double pipe heat exchanger (DPHE) with a shell and tube heat exchanger (STHE) to improve efficiency. CFD analysis is conducted on both heat exchangers to compare their coefficient of performance (COP). The DPHE currently used has low efficiency, so a STHE is proposed as it has higher efficiency and requires less area. Helical baffles within the STHE may provide further improvements.
Complete Evaluation of Vapour Compression Refrigeration System using R407C an...IRJET Journal
The document evaluates the performance of a vapor compression refrigeration system using the refrigerants R407C and R507. Experimental testing was conducted on a system using each refrigerant with variations in ambient temperature and capillary tube diameter. Results showed that both R407C and R507 had lower COP, refrigeration capacity, and higher discharge temperatures compared to R134a. R407C and R507 also used more energy than R134a. Overall, R134a demonstrated better performance than R407C and R507 across all parameters tested.
"Replacement of vapor compression system of domestic refrigerator by an eject...IRJET Journal
This document summarizes research on replacing vapor compression refrigeration systems with ejector refrigeration systems. It discusses how ejector refrigeration systems use low-grade waste heat as the power source, have fewer moving parts than compressors, and can help reduce greenhouse gas emissions. The document provides details on the design and testing of ejector refrigeration systems using various working fluids. It analyzes the performance of these systems and the impact of parameters like heat source temperature, refrigerant type, and ejector design on the system coefficient of performance.
IRJET - Design and Development of Vapour Compression Refrigeration System usi...IRJET Journal
This document describes the design and development of a vapor compression refrigeration system using a liquid heat exchanger. The system uses refrigerant blends of R600a and R290 or HFO-1234yf to increase the system's coefficient of performance (COP) while reducing global warming and ozone depletion potential compared to traditional systems using R134a. Using a liquid heat exchanger reduces the load on the compressor, allowing for greater cooling effect with lower energy input and less environmental harm. Testing confirmed the new system achieved a COP increase while lowering global warming potential to around 4, compared to 1300 for R134a, and maintaining an ozone depletion potential of zero.
IRJET- Comparative Analysis of the Performance of R22 with its Alternative ...IRJET Journal
This document compares the performance of three refrigerants: R22, R134A, and R407C. It analyzes their thermodynamic properties and performance in a vapor compression refrigeration system. The analysis finds that R407C has performance closest to R22, with COP and refrigerating effect between R22 and R134A. It concludes that R407C is a potential replacement for R22 in new and existing systems with minimal changes required.
IRJET- Life Cycle Testing of Hermetic Compressor using Hydro-Carbon RefrigerantIRJET Journal
This document summarizes a study that tested hermetic compressors using hydrocarbon refrigerants over a life cycle of 200 hours. The study selected R290 and R600a as alternative refrigerants to replace R134a and analyzed their properties. It constructed two conditioned rooms, one for maintaining a stable ambient temperature and the other for testing a window AC charged with refrigerant blends. The compressor was tested by running it for 200 hours and checking its parts. The results of compressor performance were then plotted. The methodology demonstrated how to select refrigerants, construct test rooms, install and charge an AC, test cooling parameters, and conclude on refrigerant mixtures.
To study the application of nanorefrigerant in refrigeration system a revieweSAT Journals
1. The document reviews the application of nanorefrigerants in refrigeration systems. Nanorefrigerants are a combination of nanoparticles and refrigerants that can improve heat transfer properties compared to conventional refrigerants.
2. Several studies are summarized that found improvements like increased heat transfer, higher COP, and reduced energy consumption when using nanorefrigerants made of particles like Al2O3, CuO, and TiO2 mixed with refrigerants like R134a and R600a.
3. The review concludes that nanorefrigerants show promise for making refrigeration processes more efficient and reducing their environmental impact, though more study is still needed to optimize nanoparticle type and concentration.
Experimental investigation of waste heat recovery system for domestic refrige...IAEME Publication
This document describes an experimental investigation of a waste heat recovery system for a domestic refrigerator. The system utilizes the waste heat from the refrigerator's condenser, which is typically around 32-43°C, by installing a water tank to recover heat from the compressed refrigerant gas before it enters the condenser via a process called desuperheating. Tests were conducted with the refrigerator operating normally and operating as a refrigerator-water heater. Results found that waste heat recovery from domestic refrigerators is technically feasible and can economically preheat water. The document provides details on the experimental setup, which includes modifications made to a domestic refrigerator to integrate a water tank for desuperheating, and instrumentation used to collect temperature and energy consumption data.
A Review Paper on Design of Generator in Vapour Absorption Refrigeration Systemijtsrd
In vapour absorbtion refrigeration system an absorber, a pump, a generator and a pressure reducing valve replace the compressor. We can also operate the generator with low thermal energy by exhaust heat of IC engine. The fossil fuel remain main source of energy but contribute a tremendous amount of pollutants in the environment leading to global warming ,so for the purpose of refrigerator and air conditioning a vapour absorption refrigeration system could be used. this system utilizes the wasteful heat from heavy vehicle exhaust and work on VARS which provides the cooling and reducing various costs like fuel and maintenance. The research has been done in order to recover maximum waste heat and then analyzing the system performance. Through this system the researchers has tried to find out the maximum COP. It has been found by research that generator temperature has the most effect on the release of the system. Alok Kumar Gupta | Laraib Ahamad | Prabhat Kumar Yadav | Paurush Pandit "A Review Paper on Design of Generator in Vapour Absorption Refrigeration System" Published in International Journal of Trend in Scientific Research and Development (ijtsrd), ISSN: 2456-6470, Volume-4 | Issue-4 , June 2020, URL: https://www.ijtsrd.com/papers/ijtsrd31321.pdf Paper Url :https://www.ijtsrd.com/engineering/mechanical-engineering/31321/a-review-paper-on-design-of-generator-in-vapour-absorption-refrigeration-system/alok-kumar-gupta
Review of Vapour Absorption System and Vapour Compression System.IRJET Journal
This document reviews and summarizes literature on vapour absorption and vapour compression refrigeration systems. It discusses the basic principles and components of vapour absorption systems, including single effect and double effect cycles. It also discusses vapour compression systems and their four main components: evaporator, compressor, condenser, and expansion device. The document summarizes several research papers on improving the efficiency of these systems through various parameters and working fluids. It concludes that further research is needed on smaller vapour absorption systems and the energy analysis of compression-absorption systems.
IRJET- Review of Vapour Absorption System and Vapour Compression System.IRJET Journal
This document reviews and summarizes literature on vapour absorption and vapour compression refrigeration systems. It discusses the basic principles and components of vapour absorption systems, including single effect and double effect cycles. It also discusses vapour compression systems and their four main components: evaporator, compressor, condenser, and expansion device. The document summarizes several research papers on improving the efficiency of these systems through various parameters and working fluids. It concludes that further research is needed on smaller vapour absorption systems and the energy analysis of compression-absorption systems.
IRJET- Experimental Investigation on the Performance of V.C.R. System using R...IRJET Journal
The document describes an experimental investigation of the performance of a vapor compression refrigeration system using different diameter capillary tubes. The study compares the refrigeration performance under different load conditions for capillary tubes of varying diameters. Specifically, it measures the effect on coefficient of performance and mass flow rate of the refrigerant. The experimental setup uses a domestic refrigerator with modifications to allow connection of different test capillary tubes between the evaporator inlet and compressor suction ports. Parameters like temperature, pressure, and system performance are measured for each capillary tube diameter under varying heat loads. The results are used to determine the optimal capillary tube size for maximum efficiency.
Review of Modified Vapor Absorption Refrigeration CyclesIRJET Journal
This document reviews various modifications made to vapor absorption refrigeration cycles to improve their performance. It discusses cycles that use an ejector, generator-absorber heat exchanger, booster compressor, or multiple absorption stages. The ejector cycle is found to have a 30% higher COP than a single-effect cycle. Generator-absorber heat exchanger cycles like the hybrid GAX cycle can achieve a COP as high as 0.98. A cycle with a booster compressor between the evaporator and absorber reaches a maximum COP of 0.645. The triple effect cycle demonstrates up to 132% higher COP than a single effect cycle. In general, modified cycles offer benefits like reduced losses, increased performance, and decreased energy consumption
First law thermal performance improvement of vapour compression refrigeration...editorijrei
In past time, HFC refrigerants were used in refrigeration process and they were having a global warming potential at high level. Now, as time change, and due to 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.
The nanotechnologies used in present time in the vapor compression refrigeration system. The nano refrigerant is nothing but the combined form of nano particle with the refrigerant. The nano refrigerant 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 such as copper, Al2O3having the same diameter and same volume fraction with the R718 in the secondary circuit of evaporator and to study the nature of thermo-physical properties in refrigeration process which improves the first law performance of vapour compression refrigeration system The nano particles like AL2O3, CuO and TiO2 mixed in R718 and used in secondary circuit of evaporator gives better around 95% more improvements in heat transfer coefficient which improves 11.8% to 19.05% first law thermal performances as presented in this paper
Optimization through Mathematical Modelling of Irreversibility and Other Para...IRJET Journal
This document discusses optimization of irreversibility and other parameters in a simple vapor compression refrigeration cycle using the refrigerant R-134a through mathematical modeling. It summarizes previous research that analyzed refrigeration cycles using exergy analysis and the second law of thermodynamics. The study establishes relationships between evaporator temperature and performance parameters like COP, total exergy change, irreversibility, ECOP, and second law efficiency. It analyzes these parameters for different evaporator temperatures to develop a mathematical model to calculate one parameter given a value for another. The model aims to optimize irreversibility and other factors in the refrigeration cycle.
Similar to IJREI_A thermodynamic analysis of ejector type vapour refrigeration system using eco-friendly refrigerants (20)
Modeling of variable speed compressor vapour compression refrigeration system...Husain Mehdi
Lots of researches have been done and going on based on the performance evaluation of various metallic/ nonmetallic nanoparticle suspended into the conventional fluid to enhance the heat transfer property of base fluid. Also some theoretical analysis of suspension of nanoparticle Al2O3 in conventional refrigerant. On the other hand the performance of vapour compression cycle based chiller facility using nano refrigerant yet to be analyzed with different type, concentration and diameter of nanoparticle. Such as TiO2, CuO nanoparticle suspension into conventional refrigerant with different concentration and diameter have been analyzed by several investigators and also effect of variation of concentration and nanoparticle diameter on the first and second law performance of vapour compression refrigeration system is presented. The effect of changing input parameter of VCRS using nano refrigerant also affecting significantly the evaporative heat transfer coefficient and very little condor heat transfer coefficient. The idea of Suspension nanoparticle into conventional refrigerant and theoretical analysis of VCRS using nano-refrigerant is proposed after going through extensive literature review presented in this paper.
Sensible heat energy storage technology using low cost locally available ther...Husain Mehdi
Thermal energy storage in packed beds is increasing attention due to necessary component for efficient utilization of solar energy. A one dimensional thermal model for the behavior of a packed bed is presented for low cost thermal energy sensible heat energy storage materials (i.e. stone, glass, rocks, bricks, and granite) and air as the heat transfer fluid. This model predicts successfully during storage are presented for brick and rock in a cylindrical packed bed storage unit. Explicit expression for time variation of storage material temperature and air flowing in the system have been developed and performance parameters have been computed for five storage materials.
Comparative study of parabolic trough collector through MWCNT/H2o nanofluid a...Husain Mehdi
In this present work MWCNT nanofluid and water were used as working fluid to compare the thermal performance of solar parabolic trough collector. Both the fluids were flowing through receiver at different volume flow rates 160L/h and 100L/h. Experimental tests was performed only during sunny weather and temperature at outlet of receiver was measured through thermometer after every half an hour of total testing time period. MWCNT nanofluid with weight fraction 0.01% and 0.02% and water were used to find efficiency of system and it has been seen that MWCNT nanofluid 0.02wt% with 160L/h showed better results for overall thermal efficiency among other and also an application of surfactant Triton X-100 with in MWCNT nanofluid was used to enhance the quantity of heat absorption capability of base fluid
Effect of process parameters using friction stir processing /welding of steel...Husain Mehdi
Microstructural changes and flow of material have be comprehensively studied by many researchers. A lot of studies have been conducted by changing the process parameters such as axial load, feed, speed of the tool, tool geometry, tool tilt angle etc. to find the optimum process parameters. Friction stir welding can be applied on various materials such as aluminum, manganese, copper. Till date majority of the research and development was done on aluminum alloys. This is so because Al alloys are easy to deform at relatively low temperatures (approximately below 550 Celsius). Also, they are easier to weld as compared to other materials. But these days a lot of studies are being conducted on carrying out friction stir processing on steel. This process improves mechanical properties like tensile strength, ductility, micro-hardness etc.
Vibration analysis of laminated composite beam based on virtual instrumentati...Husain Mehdi
Vibration response and its analysis is quite significant in understanding the behavior of a system. Vibrating systems produce complex time series waveforms which consist of many specific trends. These trends need to be properly extracted in order to develop methodologies for detecting system faults, its maintenance and vibration control. In the present analysis a laminated composite beam (Nylon sandwiched between Aluminum) in cantilever configuration is taken as the system model. LabVIEW is used to carry out various analyses from a range of algorithms such as standard frequency analysis, time-frequency analysis for time varying sound and vibration signals, quefrency analysis (FFT of the log of a vibration spectrum) for detecting harmonics, wavelet analysis and model based analysis for transient detection. Results of these algorithms are presented giving information for proper analysis and monitoring of the system model.
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.
IJREI_Selection model for material handling equipment’s used in flexible manu...Husain Mehdi
Material handling (MH) is important issue for every production site and has a great dependence upon the layout of the system. The important issue in the design of MH system is the selection of material handling equipment for every MH operation. Based upon the literature survey in this area, our purpose is to focus on the evaluation of the MHS-Layout of the system, due to their strong interdependence. The aim of this paper is to present a method for selection of material handling equipment (MHE) for flexible manufacturing system. In the first phase, the system consider major issues, rate of transfer, average time to transfer, flexibility etc., which is essential for the system. In second phase, the system selects the most feasible MHE types for every MH operation in a given application depends upon these major issues using fuzzy logic controller.
Introduction- e - waste – definition - sources of e-waste– hazardous substances in e-waste - effects of e-waste on environment and human health- need for e-waste management– e-waste handling rules - waste minimization techniques for managing e-waste – recycling of e-waste - disposal treatment methods of e- waste – mechanism of extraction of precious metal from leaching solution-global Scenario of E-waste – E-waste in India- case studies.
Redefining brain tumor segmentation: a cutting-edge convolutional neural netw...IJECEIAES
Medical image analysis has witnessed significant advancements with deep learning techniques. In the domain of brain tumor segmentation, the ability to
precisely delineate tumor boundaries from magnetic resonance imaging (MRI)
scans holds profound implications for diagnosis. This study presents an ensemble convolutional neural network (CNN) with transfer learning, integrating
the state-of-the-art Deeplabv3+ architecture with the ResNet18 backbone. The
model is rigorously trained and evaluated, exhibiting remarkable performance
metrics, including an impressive global accuracy of 99.286%, a high-class accuracy of 82.191%, a mean intersection over union (IoU) of 79.900%, a weighted
IoU of 98.620%, and a Boundary F1 (BF) score of 83.303%. Notably, a detailed comparative analysis with existing methods showcases the superiority of
our proposed model. These findings underscore the model’s competence in precise brain tumor localization, underscoring its potential to revolutionize medical
image analysis and enhance healthcare outcomes. This research paves the way
for future exploration and optimization of advanced CNN models in medical
imaging, emphasizing addressing false positives and resource efficiency.
Advanced control scheme of doubly fed induction generator for wind turbine us...IJECEIAES
This paper describes a speed control device for generating electrical energy on an electricity network based on the doubly fed induction generator (DFIG) used for wind power conversion systems. At first, a double-fed induction generator model was constructed. A control law is formulated to govern the flow of energy between the stator of a DFIG and the energy network using three types of controllers: proportional integral (PI), sliding mode controller (SMC) and second order sliding mode controller (SOSMC). Their different results in terms of power reference tracking, reaction to unexpected speed fluctuations, sensitivity to perturbations, and resilience against machine parameter alterations are compared. MATLAB/Simulink was used to conduct the simulations for the preceding study. Multiple simulations have shown very satisfying results, and the investigations demonstrate the efficacy and power-enhancing capabilities of the suggested control system.
KuberTENes Birthday Bash Guadalajara - K8sGPT first impressionsVictor Morales
K8sGPT is a tool that analyzes and diagnoses Kubernetes clusters. This presentation was used to share the requirements and dependencies to deploy K8sGPT in a local environment.
The CBC machine is a common diagnostic tool used by doctors to measure a patient's red blood cell count, white blood cell count and platelet count. The machine uses a small sample of the patient's blood, which is then placed into special tubes and analyzed. The results of the analysis are then displayed on a screen for the doctor to review. The CBC machine is an important tool for diagnosing various conditions, such as anemia, infection and leukemia. It can also help to monitor a patient's response to treatment.
Understanding Inductive Bias in Machine LearningSUTEJAS
This presentation explores the concept of inductive bias in machine learning. It explains how algorithms come with built-in assumptions and preferences that guide the learning process. You'll learn about the different types of inductive bias and how they can impact the performance and generalizability of machine learning models.
The presentation also covers the positive and negative aspects of inductive bias, along with strategies for mitigating potential drawbacks. We'll explore examples of how bias manifests in algorithms like neural networks and decision trees.
By understanding inductive bias, you can gain valuable insights into how machine learning models work and make informed decisions when building and deploying them.
Literature Review Basics and Understanding Reference Management.pptxDr Ramhari Poudyal
Three-day training on academic research focuses on analytical tools at United Technical College, supported by the University Grant Commission, Nepal. 24-26 May 2024
Comparative analysis between traditional aquaponics and reconstructed aquapon...bijceesjournal
The aquaponic system of planting is a method that does not require soil usage. It is a method that only needs water, fish, lava rocks (a substitute for soil), and plants. Aquaponic systems are sustainable and environmentally friendly. Its use not only helps to plant in small spaces but also helps reduce artificial chemical use and minimizes excess water use, as aquaponics consumes 90% less water than soil-based gardening. The study applied a descriptive and experimental design to assess and compare conventional and reconstructed aquaponic methods for reproducing tomatoes. The researchers created an observation checklist to determine the significant factors of the study. The study aims to determine the significant difference between traditional aquaponics and reconstructed aquaponics systems propagating tomatoes in terms of height, weight, girth, and number of fruits. The reconstructed aquaponics system’s higher growth yield results in a much more nourished crop than the traditional aquaponics system. It is superior in its number of fruits, height, weight, and girth measurement. Moreover, the reconstructed aquaponics system is proven to eliminate all the hindrances present in the traditional aquaponics system, which are overcrowding of fish, algae growth, pest problems, contaminated water, and dead fish.
Batteries -Introduction – Types of Batteries – discharging and charging of battery - characteristics of battery –battery rating- various tests on battery- – Primary battery: silver button cell- Secondary battery :Ni-Cd battery-modern battery: lithium ion battery-maintenance of batteries-choices of batteries for electric vehicle applications.
Fuel Cells: Introduction- importance and classification of fuel cells - description, principle, components, applications of fuel cells: H2-O2 fuel cell, alkaline fuel cell, molten carbonate fuel cell and direct methanol fuel cells.
UNLOCKING HEALTHCARE 4.0: NAVIGATING CRITICAL SUCCESS FACTORS FOR EFFECTIVE I...amsjournal
The Fourth Industrial Revolution is transforming industries, including healthcare, by integrating digital,
physical, and biological technologies. This study examines the integration of 4.0 technologies into
healthcare, identifying success factors and challenges through interviews with 70 stakeholders from 33
countries. Healthcare is evolving significantly, with varied objectives across nations aiming to improve
population health. The study explores stakeholders' perceptions on critical success factors, identifying
challenges such as insufficiently trained personnel, organizational silos, and structural barriers to data
exchange. Facilitators for integration include cost reduction initiatives and interoperability policies.
Technologies like IoT, Big Data, AI, Machine Learning, and robotics enhance diagnostics, treatment
precision, and real-time monitoring, reducing errors and optimizing resource utilization. Automation
improves employee satisfaction and patient care, while Blockchain and telemedicine drive cost reductions.
Successful integration requires skilled professionals and supportive policies, promising efficient resource
use, lower error rates, and accelerated processes, leading to optimized global healthcare outcomes.
2. R.S. Mishra et al/ International journal of research in engineering and innovation (IJREI), vol 1, issue 2 (2017), 40-48
41
The inter-relation between the different parts can be
expressed by the fig. 1. Boiler used low grade energy to
produce vapours to be expanded inside the ejector. Without
a compressor can this system perform saving high grade
energy and cost.
1.1 Literature Review
Tischendorf et. al. [1] focused on the differences in energy
dissipation in each component compared to the the whole
ejector refrigeration cycle. With help of this analysis,
improvement of energetic efficiency by using an ejector
was set in relation to the potential improvement in
efficiency of other components such as heat exchangers.
The refrigerants R134a and R744 (CO2) were compared in
regard to the entropy production of the heat pump system.
Kshirsagar et. al [2] proposed a combined vapour
compression-ejector refrigeration system which used the
waste heat of condenser of simple vapour compression
system and this heat was utilized to drive the binary ejector
refrigeration system. Cooling effect produced by this
binary system considered as input to the cooling effect of
basic vapour compression system. They also investigated
the characteristics and the efficient design of the ejector to
improve ejector refrigeration systems. The computational
fluid dynamics (CFD) code, FLUENT, was employed to
predict the flow phenomena and performance of CPM and
CMA steam ejectors.
M. M. Rashidi et. al. [3] studied a combined power and
refrigeration cycle that combined the Rankine cycle and
the ejector refrigeration cycle and a solar energy heat
source was used. This combined cycle produced both
power output and refrigeration output simultaneously. The
effects of the evaporator temperature, turbine inlet and
outlet pressures on the thermal and the exergetic
efficiencies were investigated. Simulation results showed
that thermal and exergy efficiencies increase with
increasing evaporator temperature. In addition, it was
found that the increase in the turbine inlet and outlet
pressure leads to the increase in the first law efficiency and
reduction in the second law efficiency.
B. J. Huang et. al. [4] developed a high-performance solar
ejector cooling system using R141b as the working fluid.
Experimentally a COP of 0.5 for a single-stage ejector was
obtained for a cooling system at a generating temperature
of 90°C, condensing temperature of 28°C, and an
evaporating temperature 8°C. For solar cooling
application, an optimum overall COP obtained was around
0.22 at a generating temperature of 95°C, evaporating
temperature of 8°C and solar radiation at 700 Wm .
R.Khajuria et. al. [5] investigated the performance
analysis of ejector refrigeration system with R404A. The
ejector refrigeration system used exhaust emission of
automobile as thermal energy for providing heat to
generator. The result showed that system using R404A as
refrigerant can be used in the ejector refrigeration system
for area ratio 7.84. Also Cooling capacity of the system
increases with increase in evaporator temperature and
generator temperature.
J.Yu et. al. [6] proposed a new ejector refrigeration system
(NERS) with an additional liquid–vapor jet pump. The jet
pump decreased the backpressure of the ejector, and the
entrainment ratio and the coefficient of performance (COP)
was increased for NERS. Two refrigerants namely R134a
and R152a were considered. Calculations showed that
COP of NERS could be improved more effectively and that
happened at the cost of more pump work. The exergy of
the new system was higher.
Kashyap et. al. [7] developed a dimensional mathematical
model to analyse the performance ejector refrigeration
cycle with working fluid R410a and compared with
performance of R134a. The result showed that
performance of R134a was better than R410a for area ratio
5.64 and 7.84.
Jain A. et. al [8] used solar cooling with the help of an
ejector refrigeration system and did mainly two analysis in
this system. By doing the analysis, the result were shown
for the refrigerants under the steady state conditions. Z
Huifan et. al. [9] designed an experimental solar ejector
refrigeration setup using R-134a as working fluid. The
average daily COP was found to be 0.18, and the average
EER was up to 3.5.
There is a huge scope of studying different eco-friendly
refrigerants that can be used as the main working fluid in
the ERS. Different combinations of temperatures can be
observed in the cycle and for all the refrigerants. Variations
of the performance parameters against the temperature can
be obtained by the software simulations. The second law
efficiency is a measure of exergy destroyed during the
cycle. Different working fluids can be compared on that
basis too. An optimum combination of parameters should
be there for the best performance. After such analysis one
can think of modifying the system and enhance its capacity
to utilize the exergy available more efficiently.
Irreversibility can be reduced by using intra-cycle heat
transfer equipment so that the heat lost will be reduced by
this method.
1.2 Ejector Refrigeration System
The system can be inferred to fig.1 which has namely a
condenser, boiler, evaporator, ejector, flash chamber
(between evaporator and ejector), pumps and throttle
valves.
3. R.S. Mishra et al/ International journal of research in engineering and innovation (IJREI), vol 1, issue 2 (2017), 40-48
42
Figure 2: Schematic of a typical two-phase ejector design [10]
A typical ejector consists of a motive nozzle, a suction
chamber, a mixing section, and a diffuser as shown in the
fig 2. The ejector converts the internal energy and pressure
of the motive fluid stream into kinetic energy. The motive
nozzle is of a converging-diverging design allowing the jet
exiting the nozzle to become supersonic. Depending on the
state of the primary fluid, the flow at the exit of the motive
nozzle might be two-phase. Flashing of the primary flow
inside the nozzle might get delayed due to thermodynamic
and hydrodynamic non-equilibrium effects.
Figure 3: the schematic of the ERS
High pressure refrigerant vapour is supplied to the nozzle
from the boiler and it is expanded in the ejector. Here, the
vapour originated from the evaporator is entrained with the
high velocity jet and it is further compressed in the thermo-
compressor. Now the kinetic energy of the mixture is
converted into static pressure and mass is discharged to the
condenser. The condensate refrigerant is returned to the
boiler to be re-circulated. Here RE is the refrigeration
effect, QIn is the heat input to the boiler and QC is the heat
rejected in condenser.
4. R.S. Mishra et al/ International journal of research in engineering and innovation (IJREI), vol 1, issue 2 (2017), 40-48
43
2. Results & Discussions
As mentioned earlier the variation of performance
parameters such as COP, Second Law Efficiency (ηII),
Refrigeration Effect (RE) and Heat Input (Qin) are studied
with the operating temperatures in the boiler, the condenser
and the evaporator through a computer simulation. The
plots showing the results are as follows. Fig 4 shows that
for the same range of boiling temperature R-423A and R-
500 show a decline in the COP with the increase in Tb. The
COP obtained for these refrigerants is also less than 1 for
most of the range, whereas R-407C is showing a flat result
for COP near 1. R502 and R507A show a more or less flat
variation from 1.2 to 1.4. For the most of the temperature
range R410A is giving highest COP from 1.4 to 1.8.
Figure 4: Variation of first law efficiency (COP) with boiler temperature (Tb)
The refrigeration effect in fig 5 is showing similar
variations as the COP. except the RE for R410A is far more
than the rest of the refrigerants in the analysis for the entire
range.
Figure 5: Variation of Refrigeration effect (RE) with boiling temperature (Tb)
5. R.S. Mishra et al/ International journal of research in engineering and innovation (IJREI), vol 1, issue 2 (2017), 40-48
44
Figure 6: Variation of Second (Exergetic efficiency) with boiler temperature (Tb)
It can be interpreted from the fig 6 that based on the exergy
loss R410A is performing the best where the second law
efficiency varies from 20% to 26%. Rest of the refrigerants
show similar variation as they show with COP.
Figure 7: Variation of heat supplied to the boiler with boiler temperature (Tb)
The boiling temperature variation shows the least heat
input required. For R502 the average heat input required is
of a range of 100kW. Both R507A and R404A shows the
similar starting heat input at 320K while for R404A it
reduces quickly near 345K. From the fig 8 we can study
the variation of COP with TC. Most of the refrigerants are
showing a flat variation for the entire operating range.
R423A provides the least COP given as .65 to .75 and
R404A has the maximum in the range of 1.8 to 2.5. R410A
has the next best performance with 1.45 to 1.75 throughout
the condenser operation
6. R.S. Mishra et al/ International journal of research in engineering and innovation (IJREI), vol 1, issue 2 (2017), 40-48
45
.
Figure 8: Variation of first Law Efficiency (COP ) with Condenser operating temperatures. (Tc)
Fig 9 shows the requirement of heat input for the boiler for
the chosen refrigerants. The heat input is low grade energy
and instead of the high grade work it is used. So we get
numerous options to arrange sources of for heat. Waste
heat from several power generating cycles can be used as
the source. The higher is the heat input the lower will be
the COP of the cycle, so shows the fig 9 that the least heat
input required is for R404A, for which with increase in the
operating temperature of the condenser, the heat required
is as low as 75kW. Although the trend is decreasing for all
the working fluids.
Figure 9: Variation of heat input required with Condenser temperatures.(Tc)
7. R.S. Mishra et al/ International journal of research in engineering and innovation (IJREI), vol 1, issue 2 (2017), 40-48
46
Figure 10: Variation of Exergetic efficiency with Condenser temperatures (Tc)
Through fig 10 we can observe that R404A gives the best
exergetic performance with the efficiency ranging from
25% to as high as 45%. Next best option is R410A with the
maximum efficiency 30%. It can be seen that R502 and
R507A are having results very close and similarly R500
and R407C are very close so these are replaceable fluids
for the cycle. The evaporator temperature shows the
required temperature to be developed. Here a 20K variation
of operating temperature has been taken. The minimum
temperature that has been chosen is -20°C and the COP
variations for the refrigerants are given in the fig 11. At
253K it can be seen that R404A has a considerably high
COP of 1.443 and at 273K it has 1.843. Over the entire
range of temperature R410 has a flat range of COP as 1.3
to 1.4
Figure 11: Variation of first Law Efficiency (COP) with evaporator temperatures (Te )
8. R.S. Mishra et al/ International journal of research in engineering and innovation (IJREI), vol 1, issue 2 (2017), 40-48
47
The refrigeration effect is the highest for R410A which is
180kW at 253K to 210kW at 273K. Despite a better COP,
R404A doesn’t provide a greater RE. R500 and R407C
are almost overlapping similarly R502 and R507A.
Figure 12: Variation refrigeration effect with evaporator temperatures (Te )
In fig 13 a variation for second law efficiency is shown. It
can be seen that as the temperature increases in the
evaporator exergy losses increase and the second law
efficiency decreases. At 253K the efficiency is the best and
it is of range of 38% for R404A and for R410A the
efficiency is of a range of 34%.
Figure 13: Variation of Exergetic efficiency with evaporator temperatures.
9. R.S. Mishra et al/ International journal of research in engineering and innovation (IJREI), vol 1, issue 2 (2017), 40-48
48
3. Conclusions
The Numerical computation is carried out for variations of
the performance parameters with the operating
temperatures in the system. The following conclusions
have been drawn.
For the variations in the boiling temperature R410A
has the best COP ranging from 1.4 to 1.8, also R410A
has the best RE.
The R410 has a exergetic efficiency ranging in 20%
to 26% when the boiling temperature is ranging from
320K to 345K. R502 has the least heat input required
for the operation of the cycle.
R404A has the maximum in the range of 1.8 to 2.5
when condenser temperature is observed to be from
313K to 328K. With the view of operation of
condenser its R404A that requires least heat input for
operation, also 45% of second law efficiency is
obtained for the same working fluid.
R502 and R507A are having results very close and
similarly R500 and R407C are very close so these are
replaceable fluids for the cycle.
At the least evaporator temperature 253K, R404A is
having COP of 1.443 and RE is generated by R410A.
Second law efficiency of 38% for R404A and for
R410A 34% is observed.
References
[1] Christian Tischendorf , Denise Janotte , Ricardo Fiorenzano
, Wilhelm Tegethoff ,” Investigation of Energy Dissipation
in an Ejector RefrigerationCycle” Modelica Conference,
Como, Italy, Sep. 20-22, 2009.
[2] Suhas D Kshirsagar, M M Deshmukh [2013],” Thermal
Design & Performance Of Combined Vapour Compression-
Ejector Refrigeration System Using R600a “International
Journal of Engineering Research and Applications Vol. 3,
Issue 2, March -April, pp.1368-1380.
[3] M. M. Rashidi, O. A. Bég a, A. Aghagoli,” Utilization of
waste heat in combined power and ejector refrigeration for a
solar energy source” Int. J. of Appl. Math and Mech. 8(17):
1-16, 2012.
[4] B. J. Huang, J. M. Chang, V. A. Peterenko, K. B. Zhuk ,” A
solar ejector cooling system using refrigerant R141b” Solar
Energy Vol. 64, Nos 4–6, pp. 223–226, 1998.
[5] Rohit Khajuria , Jagdev Singh , “Performance analysis of
ejector refrigeration system with environment friendly
refrigerant driven by exhaust emission of automobile”
Advances in Applied Science Research, 2013, 4(5):232-237.
[6] Jianlin Yu , Hua Chen, Yunfeng Ren, Yanzhong Li ,” A new
ejector refrigeration system with an additional jet pump”
Applied Thermal Engineering 26 (2006) 312–319.
[7] Sandeep Kashyap, R.C. Gupta, “Theoretical study of ejector
refrigeration system with working fluid R410a”
International Journal of Engineering Science and
Technology.
[8] Aditya Jain, S.K.Agrawal, P.Pachorkar,” Steady-State
Analysis of the Solar-Driven Ejector Refrigeration System
Using Water, Methanol, Ammonia As A Refrigerant”
International Journal of Emerging Technology and
Advanced Engineering ,Volume 2, Issue 9, September 2012.
[9] Zheng Huifan,Fan Xiaowei,Zhang Lihe ,” Study on the
Hourly Performance of A Solar Driven Ejector Refrigerant
System” The 2nd International Conference on Computer
Application and System Modeling (2012).
[10] Stefan Elbel, Predrag Hrnjak,” Ejector Refrigeration: An
overview of historical and present developments with an
emphasis on air conditioning applications” International
Refrigeration and Air Conditioning Conference at Purdue,
July 14-17, 2008.