This document summarizes a study on using artificial neural networks (ANNs) to predict the performance of a condenser system and assess fouling over time. Experiments were conducted on an industrial condenser to collect temperature and flow rate data. An ANN model was developed and trained to predict the overall heat transfer coefficient of the clean condenser system based on the input parameters. The model was then used to calculate the fouling factor by comparing the predicted clean performance to the actual performance measured over time, indicating degradation due to fouling on the heat transfer surfaces. The developed system provides a method to monitor condenser performance and identify when cleaning is needed to improve efficiency.
Evaluating mathematical heat transfer effectiveness equations using cfd techn...aeijjournal
Mathematical heat transfer equations for finned double pipe heat exchangers based on experimental work carried out in the 1970s can be programmed in a spreadsheet for repetitive use. Thus avoiding CFD analysis which can be time consuming and costly. However, it is important that such mathematical equations be evaluated for their accuracy. This paper uses CFD methods in evaluating the accuracy of mathematical equations. Several models were created with varying; geometry, flue gas entry temperature,
and flow rates. The analysis should provide designers and manufacturers a judgment on the expected level
of accuracy when using mathematical modelling methodology. This paper simultaneously identifies best
practices in carrying out such CFD analysis
Optimizing ground heat exchanger length with GeoperformX pipeJasmin Raymond
This document summarizes research on optimizing ground heat exchanger length using GeoperformX pipe. Numerical simulations and thermal response tests showed the GeoperformX pipe can reduce borehole thermal resistance by up to 31% and borehole length by 6-25% compared to conventional pipes. A case study of a campus ground source heat pump system in Grayslake, IL demonstrated a 25 foot borehole length reduction per heat exchanger using GeoperformX pipe. In conclusion, reducing borehole thermal resistance through higher conductivity pipes like GeoperformX is an effective way to optimize heat exchanger length and lower installation costs of ground source heat pump systems.
New Methods to Spatially Extend Thermal Response Test AssessmentsJasmin Raymond
This document describes two new methods for spatially extending thermal response test (TRT) assessments: 1) Inverse numerical modeling of temperature profiles from multiple boreholes at a site can be used to evaluate subsurface thermal conductivity beyond a single TRT well. 2) At a district scale, geostatistical simulation using thermal conductivity data from outcrops, boreholes, and multiple TRTs can provide stochastic realizations of subsurface properties to spatially interpolate between test locations. Both methods allow TRT assessments to be expanded beyond their typical limited spatial scope, creating new opportunities for evaluating ground source heat potential.
Insights from field experiments to conduct thermal response tests with heatin...Jasmin Raymond
This document summarizes research on using heating cable sections to conduct thermal response tests (TRTs) at lower costs than conventional methods. Key points:
- Heating cable sections allow measuring thermal conductivity profiles in boreholes, providing data to design efficient ground source heat pump systems.
- Tests conducted in Canada found heating section tests produced consistent thermal conductivity values compared to conventional TRTs, while reducing equipment needs, costs, and consumed energy by around 90%.
- Further research aims to use heating section profiles to identify favorable geological layers, explore deep geothermal resources, and correct temperature profiles for paleoclimate effects.
Performance optimization assessment for a proper heat pump technology functio...Premier Publishers
This investigation represents a thermodynamic assessment of thermal performance optimization for a proper heat pump technology suitable for district hot water production at (60-65) °C. The clean energy sources integrated with environment friendly refrigerants were studied to optimize and validate the use of Cascade heat pump technology at various configurations. Three pure, R744, R600a and R134a, and one azeotropic mixture R410A refrigerants were circulated at different cycle arrangements. Two Cascade systems (Three Cycles), single Cascade system (Two Cycles), and compound Cascade system (Three Cycles) were proposed for the present assessment. The low temperature cycle operated at evaporator temperature of (-15 to -2) °C and the high temperature condenser was set at a temperature of (70) °C. The single Cascade heat pump circulating R410A/R134a and the two Cascade R410A/R717/R134a systems showed the best heating coefficient of performance (COP). The former refrigerant pair exhibited higher heating (COP) than that of the latter by (3.6-5) % calculated at (22.5) °C low temperature cycle intermediate temperature for the whole range of test conditions. The lowest (COP) was experienced by the two Cascade heat pump technology circulating R744/R717/R134a and R744/R717/R600a refrigerant pairs. The compound Cascade heat pump is definitely a promising option for low temperature heat source technology on the long term basis due to its low running cost for heating load generation. The heating (COP) showed a range of (2 to 2.7) at (70 %) compressor isentropic efficiency according to the system type, refrigerant pair and operating conditions considered in the present work. Any improvement for the compressor isentropic efficiency provides a valuable augmentation for the heating (COP) of the Cascade heat pump.
This document presents a theoretical and experimental analysis of a direct-fired double effect lithium bromide/water absorption chiller located at a lighting technology company in Egypt. The chiller has a cooling capacity of 500 tons and uses a parallel flow configuration. Temperature measurements were taken at various points in the chiller components in July 2013 and July 2014. Mathematical equations were developed to model the chiller and estimate the coefficient of performance and heat transfer rates based on temperature and flow rate data. Theoretical and experimental analyses were conducted to evaluate how the COP is affected by factors like heat exchanger effectiveness and circulation ratio. The results show that the chiller's COP was lower in 2014 compared to 2013, possibly due to degradation of the heat ex
Pinch analysis technique to optimize heat exchangerK Vivek Varkey
This document summarizes a student project applying pinch analysis to optimize the heat exchanger network (HEN) for a CFU unit at an ONGC Hazira plant. The student calculated heat duties for 5 heat exchangers and determined the minimum hot and cold utility requirements. By drawing temperature interval diagrams, the student designed an optimized HEN that couples process streams to maximize heat exchange and minimize utility needs. The optimized design was found to reduce heating utility needs by 83.4% and cooling needs by 33.8% compared to the current design.
This document discusses methods for assessing the energy performance of heat exchangers over time. It describes calculating the overall heat transfer coefficient U to determine if fouling or other issues have reduced efficiency. The procedure involves monitoring operating parameters, calculating thermal properties, and determining U by measuring the heat duty, surface area, and log mean temperature difference. An example application to a liquid-liquid exchanger is provided, comparing test data to design specifications to identify potential fouling issues.
Evaluating mathematical heat transfer effectiveness equations using cfd techn...aeijjournal
Mathematical heat transfer equations for finned double pipe heat exchangers based on experimental work carried out in the 1970s can be programmed in a spreadsheet for repetitive use. Thus avoiding CFD analysis which can be time consuming and costly. However, it is important that such mathematical equations be evaluated for their accuracy. This paper uses CFD methods in evaluating the accuracy of mathematical equations. Several models were created with varying; geometry, flue gas entry temperature,
and flow rates. The analysis should provide designers and manufacturers a judgment on the expected level
of accuracy when using mathematical modelling methodology. This paper simultaneously identifies best
practices in carrying out such CFD analysis
Optimizing ground heat exchanger length with GeoperformX pipeJasmin Raymond
This document summarizes research on optimizing ground heat exchanger length using GeoperformX pipe. Numerical simulations and thermal response tests showed the GeoperformX pipe can reduce borehole thermal resistance by up to 31% and borehole length by 6-25% compared to conventional pipes. A case study of a campus ground source heat pump system in Grayslake, IL demonstrated a 25 foot borehole length reduction per heat exchanger using GeoperformX pipe. In conclusion, reducing borehole thermal resistance through higher conductivity pipes like GeoperformX is an effective way to optimize heat exchanger length and lower installation costs of ground source heat pump systems.
New Methods to Spatially Extend Thermal Response Test AssessmentsJasmin Raymond
This document describes two new methods for spatially extending thermal response test (TRT) assessments: 1) Inverse numerical modeling of temperature profiles from multiple boreholes at a site can be used to evaluate subsurface thermal conductivity beyond a single TRT well. 2) At a district scale, geostatistical simulation using thermal conductivity data from outcrops, boreholes, and multiple TRTs can provide stochastic realizations of subsurface properties to spatially interpolate between test locations. Both methods allow TRT assessments to be expanded beyond their typical limited spatial scope, creating new opportunities for evaluating ground source heat potential.
Insights from field experiments to conduct thermal response tests with heatin...Jasmin Raymond
This document summarizes research on using heating cable sections to conduct thermal response tests (TRTs) at lower costs than conventional methods. Key points:
- Heating cable sections allow measuring thermal conductivity profiles in boreholes, providing data to design efficient ground source heat pump systems.
- Tests conducted in Canada found heating section tests produced consistent thermal conductivity values compared to conventional TRTs, while reducing equipment needs, costs, and consumed energy by around 90%.
- Further research aims to use heating section profiles to identify favorable geological layers, explore deep geothermal resources, and correct temperature profiles for paleoclimate effects.
Performance optimization assessment for a proper heat pump technology functio...Premier Publishers
This investigation represents a thermodynamic assessment of thermal performance optimization for a proper heat pump technology suitable for district hot water production at (60-65) °C. The clean energy sources integrated with environment friendly refrigerants were studied to optimize and validate the use of Cascade heat pump technology at various configurations. Three pure, R744, R600a and R134a, and one azeotropic mixture R410A refrigerants were circulated at different cycle arrangements. Two Cascade systems (Three Cycles), single Cascade system (Two Cycles), and compound Cascade system (Three Cycles) were proposed for the present assessment. The low temperature cycle operated at evaporator temperature of (-15 to -2) °C and the high temperature condenser was set at a temperature of (70) °C. The single Cascade heat pump circulating R410A/R134a and the two Cascade R410A/R717/R134a systems showed the best heating coefficient of performance (COP). The former refrigerant pair exhibited higher heating (COP) than that of the latter by (3.6-5) % calculated at (22.5) °C low temperature cycle intermediate temperature for the whole range of test conditions. The lowest (COP) was experienced by the two Cascade heat pump technology circulating R744/R717/R134a and R744/R717/R600a refrigerant pairs. The compound Cascade heat pump is definitely a promising option for low temperature heat source technology on the long term basis due to its low running cost for heating load generation. The heating (COP) showed a range of (2 to 2.7) at (70 %) compressor isentropic efficiency according to the system type, refrigerant pair and operating conditions considered in the present work. Any improvement for the compressor isentropic efficiency provides a valuable augmentation for the heating (COP) of the Cascade heat pump.
This document presents a theoretical and experimental analysis of a direct-fired double effect lithium bromide/water absorption chiller located at a lighting technology company in Egypt. The chiller has a cooling capacity of 500 tons and uses a parallel flow configuration. Temperature measurements were taken at various points in the chiller components in July 2013 and July 2014. Mathematical equations were developed to model the chiller and estimate the coefficient of performance and heat transfer rates based on temperature and flow rate data. Theoretical and experimental analyses were conducted to evaluate how the COP is affected by factors like heat exchanger effectiveness and circulation ratio. The results show that the chiller's COP was lower in 2014 compared to 2013, possibly due to degradation of the heat ex
Pinch analysis technique to optimize heat exchangerK Vivek Varkey
This document summarizes a student project applying pinch analysis to optimize the heat exchanger network (HEN) for a CFU unit at an ONGC Hazira plant. The student calculated heat duties for 5 heat exchangers and determined the minimum hot and cold utility requirements. By drawing temperature interval diagrams, the student designed an optimized HEN that couples process streams to maximize heat exchange and minimize utility needs. The optimized design was found to reduce heating utility needs by 83.4% and cooling needs by 33.8% compared to the current design.
This document discusses methods for assessing the energy performance of heat exchangers over time. It describes calculating the overall heat transfer coefficient U to determine if fouling or other issues have reduced efficiency. The procedure involves monitoring operating parameters, calculating thermal properties, and determining U by measuring the heat duty, surface area, and log mean temperature difference. An example application to a liquid-liquid exchanger is provided, comparing test data to design specifications to identify potential fouling issues.
Effect of nanofluids and mass flow rate of air on heat transfer rate in autom...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.
This document discusses the use of an "over-conductivity function" to model the natural cooling process in steam turbines. It summarizes previous research on modeling natural cooling and validates the over-conductivity approach on three additional turbines. The over-conductivity function replaces complex fluid dynamics with an equivalent higher conductivity, allowing faster simulations while maintaining 15-18°C accuracy compared to temperature measurements during natural cooling periods of over 100 hours.
Experimental Study of Heat Transfer Enhancement by using ZnO and Al2O3 Water ...IRJET Journal
This study experimentally analyzed heat transfer enhancement using ZnO and Al2O3 water-based nanofluids in a car radiator. An experimental setup similar to a car's cooling system was developed. Different volume concentrations of nanoparticles (0.1-0.4%) were tested in water. Heat transfer of the nanofluids increased with rising volume concentration and flow rate. ZnO nanofluid provided the highest heat transfer, up to 70% more than water. The maximum heat transfer occurred at a 0.2% volume concentration and 8 L/min flow rate for both nanofluids. Overall, ZnO nanofluid showed the best thermal performance and is a promising coolant for improving heat dissipation in car radiators.
This document contains information about experiments in heat transfer lab manual. It includes 13 experiments related to different modes of heat transfer like through composite walls, critical heat flux, measurement of surface emissivity, forced convection, lagged pipe, natural convection, heat exchangers, pin-fin, Stefan-Boltzmann apparatus, thermal conductivity of concentric sphere and metal rod, transient heat conduction, heat pipe demonstration. For each experiment, it provides introduction, description of apparatus, experimentation procedure, observations, calculations and precautions.
Modeling and simulation of temperature profiles in a reactiveAlexander Decker
This document summarizes a study that developed a mathematical model to simulate temperature profiles in a reactive distillation system for the esterification of acetic anhydride and methanol. The model was based on reaction kinetics determined from experimental temperature data. Simulation results showed good agreement with experiments, with deviations less than 4%. An overview of the experimental setup and procedures for thermistor calibration and reactor calibration are also provided.
Experimental investigate to obtain the effectiveness of regenerator using Air.IJESFT
The regenerator is a kind of heat exchanger that provides a way to get the gas to the low temperature with as much potential work (cooling power) as possible without carrying a lot of heat with it. It doesn’t put heat in or out of the system but it absorbs heat from the gas on one part of the pressure cycle and returns heat to the gas on the other part.
More recent applications of regenerators in cryogenic systems can be found in small cryogenic refrigerators (cryocoolers). Systems such as the Stirling Gifford-McMahon, pulse tube, Solvay, Vuilleumier and magnetic cycle refrigerators all use either a static or rotary regenerator. In fact, the success these coolers have achieved is directly related to the characteristics of compact size and efficiency of the regenerator.
Regenerator effectiveness of 99% results in 21% loss of refrigeration effect, similarly regenerator effectiveness of 98% results in 42% loss of refrigeration effect, with refrigeration effectiveness of 95.238% the loss of refrigeration is 100%. i.e. no net cooling is produced.
In cryogenic applications the regenerator is typically made up of 100 to 500 meshes SS 304, Phosphorous bronze screens or small lead spheres (150 to 300 micro meters) are used, that are tightly packed together and held in place on either end in the same manner.
To develop experimental setup at our laboratory level by using air as working fluid and find out the effectiveness of various regenerative materials is basic goal of this work.
This document summarizes a study that uses computational fluid dynamics (CFD) to analyze the flow and heat transfer characteristics of different elliptical pin fin heat sink configurations. The study aims to examine the effects of elliptical pin fin design parameters on heat sink performance. CFD simulations are conducted using ANSYS Fluent software to compute the thermal resistance, heat transfer coefficient, and surface Nusselt number of plate fin and elliptical pin fin heat sinks. Results show that the elliptical pin fin heat sink has better heat transfer performance than the plate fin heat sink. Simulation results for thermal resistance and pressure drop are validated against experimental data from previous studies.
The document summarizes an experimental investigation of convection heat transfer for laminar flow in an inclined annulus. An annular copper pipe was exposed to a constant heat flux and rotated through inclination angles from 0° to 90° in 10° increments. Results showed that the heat transfer coefficient decreased inversely with inclination angle, with a maximum 6.6% reduction at 90°. Reynolds number also decreased inversely with angle from 1750 to 1700. Experimental results closely matched a correlation up to 40° inclination. The study found inclination angle had a small effect on heat transfer for laminar flow in the annulus.
As run boiler performance assessment for energy efficiencyD.Pawan Kumar
The document discusses methods for assessing the energy efficiency of boiler performance. It describes standards from British and ASME for testing boilers under steady load conditions. The direct and indirect methods for determining boiler efficiency are outlined. Instruments required are listed, including flue gas analyzers, temperature indicators, and facilities for analyzing fuel and water samples. Key aspects of indirect method heat balance calculations for a coal-fired boiler are mentioned. Best practices are listed for improving boiler selection, operation and maintenance for energy efficiency.
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.
Isentropic Blow-Down Process and Discharge CoefficientSteven Cooke
The document describes an experiment to study the transient discharge of a pressurized tank through orifices of varying diameters, as well as a long tube, and compare the actual blowdown processes to an ideal isentropic process. An MKS pressure transducer and T-type thermocouple were calibrated. Pressure and temperature data were recorded during blowdown for each orifice/tube. The actual temperature decayed much more than the calculated isentropic temperature due to heat transfer. Discharge coefficients were calculated and ranged from 0.59 to 0.71, decreasing with smaller orifices/tubes due to friction.
Analytical Solution of Compartment Based Double Pipe Heat Exchanger using Di...IRJET Journal
This document discusses analytical solutions for a compartment-based double pipe heat exchanger model using the differential transform method. The model considers transformer oil as the hot fluid and water as the coolant fluid flowing in parallel through two compartments of the heat exchanger. Analytical expressions for the temperature profiles of the hot and cold fluids over time are derived. The solutions are shown to converge with increasing terms in the series solutions.
IRJET- Study of Heat Transfer Coefficient in Natural and Forced Convection by...IRJET Journal
The document describes an experimental study on heat transfer by natural and forced convection using brass rods with different surface finishes (plane, semi-rough, and fully rough). An experimental setup was designed to measure the heat transfer coefficient. Brass rods were heated electrically and thermocouples measured the temperature distribution. Experiments were conducted with and without airflow over the rods. The results showed higher heat transfer coefficients and more uniform temperature distributions with forced convection compared to natural convection. Calculations were presented to determine heat transfer rates, average temperatures, heat transfer coefficients, and other parameters for different test conditions.
Experimental and Exergy Analysis of A Double Pipe Heat Exchanger for Parallel...IJERA Editor
This paper presents For Experimental and Exergy Analysis of a Double Pipe Heat Exchanger for Parallel- flow Arrangement. The Double pipe heat exchanger is one of the Different types of heat exchangers. double-pipe exchanger because one fluid flows inside a pipe and the other fluid flows between that pipe and another pipe that surrounds the first.In a parallel flow, both the hot and cold fluids enter the Heatexchanger at same end andmove in same direction. The present work is taken up to carry experimental work and the exergy analysis based on second law analysis of a Double-Pipe Heat Exchanger. In experimental set up hot water and cold water will be used working fluids. The inlet Hot water will be varied from 40 0C and 50 0C and cold water temperature will be varied from between 15 and 20. It has been planned to find effects of the inlet condition of both working fluid flowing through the heat exchanger on the heat transfer characteristics, entropy generation, and Exergy loss. The Mathematical modelling of heat exchanger will based on the conservation equation of mass, energy and based on second law of thermodynamics to find entropy generation and exergy losses.
This document presents a theoretical analysis of the performance of a vapor compression refrigeration system using different refrigerants: R-12, R134a, and R1234yf. The analysis uses a computational model based on the first law of thermodynamics to investigate the effects of evaporating temperature, subcooling, condenser temperature, and liquid-vapor heat exchanger effectiveness on the system's coefficient of performance and refrigerating capacity. The results show that R1234yf has the highest relative capacity increase with increased subcooling and the highest percentage increase in COP. R134a requires the most compressor work. R1234yf is identified as a promising alternative to R134a due to its low global warming potential
The document discusses energy performance assessment of boilers. It defines key terms like boiler efficiency and evaporation ratio. It describes standards for boiler testing from British, ASME, and Indian standards. It then explains the direct and indirect methods for testing boiler efficiency, including measuring inputs of fuel, air, and outputs of steam. Instruments used for assessment are also outlined. Formats for collecting boiler specifications and performance data are provided. The document calculates boiler efficiency using an example and discusses factors affecting boiler performance.
OPTIMIZING ENERGY PRODUCTION WITH A LOW/INTERMITTENT WIND RESOURCE David Parker
This document describes a senior project to design and develop maximum power point tracking (MPPT) and load control electronics for a small 40-watt vertical axis wind turbine to optimize energy production from a low or intermittent wind resource. It will involve building a 2.5 ft by 3.3 ft vertical axis wind turbine based on an existing design, coupling it to an axial flux permanent magnet generator, and developing power electronics to rectify the AC output, perform DC-DC conversion, implement MPPT, and provide overspeed protection. The goal is to extract more energy from the wind resource by ensuring the turbine operates at its maximum power point compared to an unregulated system.
This document provides an overview of a hydro power plant project. It discusses site selection factors like water availability and storage. It describes the basic components and working of a hydro power plant including the catchment area, dam, penstocks, turbines, generators, and powerhouse. It classifies hydro plants by head, lists common turbine types, and discusses advantages like no fuel costs and disadvantages like high initial costs. Examples of hydro plants in Gujarat are also mentioned.
SIMULATION OF SOLAR THERMAL CENTRAL RECEIVER POWER PLANT AND EFFECT OF WEATHE...IAEME Publication
Mathematical model is presented for prediction of thermal losses from central receiver solar thermal power plant. Results obtained are verified with evidence from solar experiments. Code is developed for studying the effect of variation of weather conditions i.e. variation of incident solar radiation, wind speed and ambient temperature during the entire year on the thermal performance of receiver. Thermal losses have its effect on efficiency of the receiver and hence the overall cost of solar thermal to electric power. Radiation and convection losses are the major components of thermal losses. Simulation is done for weather data of Jaipur city of India
Design, test and mathematica modeling of parabolic trough solat collectors (P...Marco Sotte
Parabolic Trough Collectors are widespread in CSP applications. Their adoption is less developed in industrial heat demand applications. In the present thesis the design and test of two prototypes of PTC for the thermal loads in the range 80 - 250 °C is described. A mathematical model has also been developed to predict optical efficiency and thermal losses for any PTC. The model has been validated through comparison with the experimental results on the prototypes. Then it has been included in a custom-built simulation environment to predict yearly perfor- mances of a PTC field coupled with an industrial process heat demand. Energetic results are shown and final considerations are drawn for this application.
Effect of nanofluids and mass flow rate of air on heat transfer rate in autom...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.
This document discusses the use of an "over-conductivity function" to model the natural cooling process in steam turbines. It summarizes previous research on modeling natural cooling and validates the over-conductivity approach on three additional turbines. The over-conductivity function replaces complex fluid dynamics with an equivalent higher conductivity, allowing faster simulations while maintaining 15-18°C accuracy compared to temperature measurements during natural cooling periods of over 100 hours.
Experimental Study of Heat Transfer Enhancement by using ZnO and Al2O3 Water ...IRJET Journal
This study experimentally analyzed heat transfer enhancement using ZnO and Al2O3 water-based nanofluids in a car radiator. An experimental setup similar to a car's cooling system was developed. Different volume concentrations of nanoparticles (0.1-0.4%) were tested in water. Heat transfer of the nanofluids increased with rising volume concentration and flow rate. ZnO nanofluid provided the highest heat transfer, up to 70% more than water. The maximum heat transfer occurred at a 0.2% volume concentration and 8 L/min flow rate for both nanofluids. Overall, ZnO nanofluid showed the best thermal performance and is a promising coolant for improving heat dissipation in car radiators.
This document contains information about experiments in heat transfer lab manual. It includes 13 experiments related to different modes of heat transfer like through composite walls, critical heat flux, measurement of surface emissivity, forced convection, lagged pipe, natural convection, heat exchangers, pin-fin, Stefan-Boltzmann apparatus, thermal conductivity of concentric sphere and metal rod, transient heat conduction, heat pipe demonstration. For each experiment, it provides introduction, description of apparatus, experimentation procedure, observations, calculations and precautions.
Modeling and simulation of temperature profiles in a reactiveAlexander Decker
This document summarizes a study that developed a mathematical model to simulate temperature profiles in a reactive distillation system for the esterification of acetic anhydride and methanol. The model was based on reaction kinetics determined from experimental temperature data. Simulation results showed good agreement with experiments, with deviations less than 4%. An overview of the experimental setup and procedures for thermistor calibration and reactor calibration are also provided.
Experimental investigate to obtain the effectiveness of regenerator using Air.IJESFT
The regenerator is a kind of heat exchanger that provides a way to get the gas to the low temperature with as much potential work (cooling power) as possible without carrying a lot of heat with it. It doesn’t put heat in or out of the system but it absorbs heat from the gas on one part of the pressure cycle and returns heat to the gas on the other part.
More recent applications of regenerators in cryogenic systems can be found in small cryogenic refrigerators (cryocoolers). Systems such as the Stirling Gifford-McMahon, pulse tube, Solvay, Vuilleumier and magnetic cycle refrigerators all use either a static or rotary regenerator. In fact, the success these coolers have achieved is directly related to the characteristics of compact size and efficiency of the regenerator.
Regenerator effectiveness of 99% results in 21% loss of refrigeration effect, similarly regenerator effectiveness of 98% results in 42% loss of refrigeration effect, with refrigeration effectiveness of 95.238% the loss of refrigeration is 100%. i.e. no net cooling is produced.
In cryogenic applications the regenerator is typically made up of 100 to 500 meshes SS 304, Phosphorous bronze screens or small lead spheres (150 to 300 micro meters) are used, that are tightly packed together and held in place on either end in the same manner.
To develop experimental setup at our laboratory level by using air as working fluid and find out the effectiveness of various regenerative materials is basic goal of this work.
This document summarizes a study that uses computational fluid dynamics (CFD) to analyze the flow and heat transfer characteristics of different elliptical pin fin heat sink configurations. The study aims to examine the effects of elliptical pin fin design parameters on heat sink performance. CFD simulations are conducted using ANSYS Fluent software to compute the thermal resistance, heat transfer coefficient, and surface Nusselt number of plate fin and elliptical pin fin heat sinks. Results show that the elliptical pin fin heat sink has better heat transfer performance than the plate fin heat sink. Simulation results for thermal resistance and pressure drop are validated against experimental data from previous studies.
The document summarizes an experimental investigation of convection heat transfer for laminar flow in an inclined annulus. An annular copper pipe was exposed to a constant heat flux and rotated through inclination angles from 0° to 90° in 10° increments. Results showed that the heat transfer coefficient decreased inversely with inclination angle, with a maximum 6.6% reduction at 90°. Reynolds number also decreased inversely with angle from 1750 to 1700. Experimental results closely matched a correlation up to 40° inclination. The study found inclination angle had a small effect on heat transfer for laminar flow in the annulus.
As run boiler performance assessment for energy efficiencyD.Pawan Kumar
The document discusses methods for assessing the energy efficiency of boiler performance. It describes standards from British and ASME for testing boilers under steady load conditions. The direct and indirect methods for determining boiler efficiency are outlined. Instruments required are listed, including flue gas analyzers, temperature indicators, and facilities for analyzing fuel and water samples. Key aspects of indirect method heat balance calculations for a coal-fired boiler are mentioned. Best practices are listed for improving boiler selection, operation and maintenance for energy efficiency.
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.
Isentropic Blow-Down Process and Discharge CoefficientSteven Cooke
The document describes an experiment to study the transient discharge of a pressurized tank through orifices of varying diameters, as well as a long tube, and compare the actual blowdown processes to an ideal isentropic process. An MKS pressure transducer and T-type thermocouple were calibrated. Pressure and temperature data were recorded during blowdown for each orifice/tube. The actual temperature decayed much more than the calculated isentropic temperature due to heat transfer. Discharge coefficients were calculated and ranged from 0.59 to 0.71, decreasing with smaller orifices/tubes due to friction.
Analytical Solution of Compartment Based Double Pipe Heat Exchanger using Di...IRJET Journal
This document discusses analytical solutions for a compartment-based double pipe heat exchanger model using the differential transform method. The model considers transformer oil as the hot fluid and water as the coolant fluid flowing in parallel through two compartments of the heat exchanger. Analytical expressions for the temperature profiles of the hot and cold fluids over time are derived. The solutions are shown to converge with increasing terms in the series solutions.
IRJET- Study of Heat Transfer Coefficient in Natural and Forced Convection by...IRJET Journal
The document describes an experimental study on heat transfer by natural and forced convection using brass rods with different surface finishes (plane, semi-rough, and fully rough). An experimental setup was designed to measure the heat transfer coefficient. Brass rods were heated electrically and thermocouples measured the temperature distribution. Experiments were conducted with and without airflow over the rods. The results showed higher heat transfer coefficients and more uniform temperature distributions with forced convection compared to natural convection. Calculations were presented to determine heat transfer rates, average temperatures, heat transfer coefficients, and other parameters for different test conditions.
Experimental and Exergy Analysis of A Double Pipe Heat Exchanger for Parallel...IJERA Editor
This paper presents For Experimental and Exergy Analysis of a Double Pipe Heat Exchanger for Parallel- flow Arrangement. The Double pipe heat exchanger is one of the Different types of heat exchangers. double-pipe exchanger because one fluid flows inside a pipe and the other fluid flows between that pipe and another pipe that surrounds the first.In a parallel flow, both the hot and cold fluids enter the Heatexchanger at same end andmove in same direction. The present work is taken up to carry experimental work and the exergy analysis based on second law analysis of a Double-Pipe Heat Exchanger. In experimental set up hot water and cold water will be used working fluids. The inlet Hot water will be varied from 40 0C and 50 0C and cold water temperature will be varied from between 15 and 20. It has been planned to find effects of the inlet condition of both working fluid flowing through the heat exchanger on the heat transfer characteristics, entropy generation, and Exergy loss. The Mathematical modelling of heat exchanger will based on the conservation equation of mass, energy and based on second law of thermodynamics to find entropy generation and exergy losses.
This document presents a theoretical analysis of the performance of a vapor compression refrigeration system using different refrigerants: R-12, R134a, and R1234yf. The analysis uses a computational model based on the first law of thermodynamics to investigate the effects of evaporating temperature, subcooling, condenser temperature, and liquid-vapor heat exchanger effectiveness on the system's coefficient of performance and refrigerating capacity. The results show that R1234yf has the highest relative capacity increase with increased subcooling and the highest percentage increase in COP. R134a requires the most compressor work. R1234yf is identified as a promising alternative to R134a due to its low global warming potential
The document discusses energy performance assessment of boilers. It defines key terms like boiler efficiency and evaporation ratio. It describes standards for boiler testing from British, ASME, and Indian standards. It then explains the direct and indirect methods for testing boiler efficiency, including measuring inputs of fuel, air, and outputs of steam. Instruments used for assessment are also outlined. Formats for collecting boiler specifications and performance data are provided. The document calculates boiler efficiency using an example and discusses factors affecting boiler performance.
OPTIMIZING ENERGY PRODUCTION WITH A LOW/INTERMITTENT WIND RESOURCE David Parker
This document describes a senior project to design and develop maximum power point tracking (MPPT) and load control electronics for a small 40-watt vertical axis wind turbine to optimize energy production from a low or intermittent wind resource. It will involve building a 2.5 ft by 3.3 ft vertical axis wind turbine based on an existing design, coupling it to an axial flux permanent magnet generator, and developing power electronics to rectify the AC output, perform DC-DC conversion, implement MPPT, and provide overspeed protection. The goal is to extract more energy from the wind resource by ensuring the turbine operates at its maximum power point compared to an unregulated system.
This document provides an overview of a hydro power plant project. It discusses site selection factors like water availability and storage. It describes the basic components and working of a hydro power plant including the catchment area, dam, penstocks, turbines, generators, and powerhouse. It classifies hydro plants by head, lists common turbine types, and discusses advantages like no fuel costs and disadvantages like high initial costs. Examples of hydro plants in Gujarat are also mentioned.
SIMULATION OF SOLAR THERMAL CENTRAL RECEIVER POWER PLANT AND EFFECT OF WEATHE...IAEME Publication
Mathematical model is presented for prediction of thermal losses from central receiver solar thermal power plant. Results obtained are verified with evidence from solar experiments. Code is developed for studying the effect of variation of weather conditions i.e. variation of incident solar radiation, wind speed and ambient temperature during the entire year on the thermal performance of receiver. Thermal losses have its effect on efficiency of the receiver and hence the overall cost of solar thermal to electric power. Radiation and convection losses are the major components of thermal losses. Simulation is done for weather data of Jaipur city of India
Design, test and mathematica modeling of parabolic trough solat collectors (P...Marco Sotte
Parabolic Trough Collectors are widespread in CSP applications. Their adoption is less developed in industrial heat demand applications. In the present thesis the design and test of two prototypes of PTC for the thermal loads in the range 80 - 250 °C is described. A mathematical model has also been developed to predict optical efficiency and thermal losses for any PTC. The model has been validated through comparison with the experimental results on the prototypes. Then it has been included in a custom-built simulation environment to predict yearly perfor- mances of a PTC field coupled with an industrial process heat demand. Energetic results are shown and final considerations are drawn for this application.
To download, head to -
http://solarreference.com/parabolic-trough-collectors-comparison/
A detailed comparison of different types of parabolic trough collectors on the basis of specifications, technology, material etc. If CSP is your arena, this is one presentation you just can't miss !!!
Source: NREL
For more quality resources visit us at http://solarreference.com
CFD Analysis of a Heat Collector Element in a Solar Parabolic Trough Collector iMentor Education
A numerical study of the performance of a solar Parabolic Trough Collector (PTC) has been done focusing on its receiver. The receiver consisting of a glass-shield enclosing a Heat Collector Element (HCE) with vacuum in the annular space has been subjected to seasonal and diurnal variations of solar radiation along with the
concentrated heat flux reflected from the parabolic trough mirror for conditions at Pune, India. The HCE is modeled as a metallic tube with thermic fluid Therminol-VP1TM flowing through it at low Reynolds number under thermally developing conditions with highly temperature dependent properties. The highly asymmetric
nature of the physics for thermal and turbulent flow conditions make it imperative to consider a complete three dimensional domain for the conjugate heat transfer analysis. The conduction, convection and radiation heat transfer effects have been modeled with radiation restricted within the annular region using the S2S radiation
model. The solar fluxes have been modeled using the Solar Load Model also accounting for the shadowing effects for semi-transparent and opaque surfaces. The pressure drop in the thermic fluid flow is comparatively uniform throughout the day during winter conditions while the fluid gets heated up 4 times more at noon
compared to morning. The summer conditions exhibit a 2.5 times higher pressure drop at noon compared to the morning conditions. The comprehensive analysis is performed using the finite volume based CFD code of ANSYS FLUENT 12.1 and verifies the huge potential that PTC holds for high temperature applications in
concentrated solar power plants.
Hydro power plant presentation project by pratik diyora 100420106008Pratik Diyora
This document summarizes a student project on a hydroelectric power plant. It includes sections on the basic components and principles of hydroelectricity including dams, intake, penstocks, turbines, generators, transformers, and power houses. It also describes different types of hydroelectric plants based on head including low, medium, and high head schemes. World's largest hydroelectric plants like China's Three Gorges Dam and India's largest plants including Tehri Dam and Sardar Sarovar Dam are highlighted. The document is intended to provide an overview of hydroelectric power generation.
This document provides an overview of hydro power plant components and types. It discusses the three types of power houses: surface, semi-underground, and underground. Surface power houses have components on the surface but are limited by topography. Semi-underground power houses combine advantages of surface and underground. Underground power houses are located entirely inside mountains with access tunnels. The document also summarizes the main components of hydro power stations including dams/barrages, water conductor systems, and power houses as well as different types of hydro power projects.
The document discusses maximum power point tracking (MPPT) for photovoltaic systems. It begins with an introduction to MPPT and explains that MPPT is an algorithm included in solar charge controllers to extract the maximum available power from PV modules under different operating conditions. It then provides details on various MPPT techniques like perturb and observe method and incremental conductance method. The document also presents the mathematical model and system modeling of an MPPT system and discusses the advantages of using MPPT to increase energy extraction from solar panels.
Concentrated solar power systems use mirrors to focus sunlight and heat a fluid to produce steam that drives turbines to generate electricity. There are three main types: linear concentrators use curved mirrors to heat fluid in tubes; dish/engine systems use mirrored dishes to concentrate sunlight onto receivers connected to Stirling engines; and power tower systems use many heliostat mirrors to focus sunlight onto a receiver at the top of a tower to heat a fluid and produce steam. Concentrated solar power is advantageous because it is non-polluting, can displace fossil fuel plants, and is efficient and cost-effective to deploy relatively quickly to reduce carbon emissions compared to natural gas systems. Ideal places for concentrated solar power include desert regions of Australia and Africa
The document summarizes the fabrication and testing of a heat exchanger test rig. Key points:
- The test rig was designed and built to study a counter-flow tube heat exchanger using aluminum sheets and tubes.
- Finite element analysis was performed on the rig design to analyze stresses. Water was heated to 40°C and pumped through one side while tap water entered the other side.
- Effectiveness-NTU method was used to calculate theoretical outlet temperatures which were compared to experimental readings to determine error percentages.
This research paper models and controls the temperature of a shell and tube heat exchanger using two PID controller tuning methods. An ARMAX model is obtained from experimental PRBS data to mathematically model the heat exchanger dynamics. PID settings are designed using Internal Model Control (IMC) tuning and relay auto-tuning methods. Experimental results show that the IMC-tuned PID controller provides better control of the cold fluid outlet temperature in terms of error metrics than the relay auto-tuned controller.
Cfd and conjugate heat transfer analysis of heat sinks with different fin geo...eSAT Journals
This document discusses a computational fluid dynamics (CFD) and conjugate heat transfer analysis of different fin geometries for heat sinks used in electronics cooling. Five fin geometries - zigzag, fluted, slanted mirror, custom pin fin, and staggered array - were analyzed under different heat loads and air velocity. The results show that the slanted mirror geometry provided the best thermal performance with the lowest thermal resistance and highest heat transfer coefficient, while maintaining a relatively low pressure drop. CFD simulations using ANSYS Fluent were conducted to analyze fluid flow, heat transfer, temperature distribution, and thermal performance of the different heat sink designs.
Design and Thermal Analysis of Hydraulic Oil Cooler by using Computational Fl...IRJET Journal
This document describes a study analyzing the thermal performance of a hydraulic oil cooler using computational fluid dynamics (CFD). It involves:
1) Designing a hydraulic oil cooler with cross-flow heat exchanger cores to transfer heat from hot hydraulic oil into ambient air.
2) Developing a thermal model and equations to calculate heat transfer rates, oil/air temperatures, heat transfer coefficients, and surface area required.
3) Validating the model through experimental testing of an oil cooler setup and comparing predicted vs actual temperature values.
CFD Investigation of Compact Heat Exchanger Having Different Fins with Nanofl...IRJET Journal
This document summarizes research on using computational fluid dynamics (CFD) to investigate heat transfer in a compact heat exchanger with different fin types and titanium dioxide nanofluid. It discusses past research on various techniques for enhancing heat transfer and reducing pressure losses in heat exchangers. The document then outlines the objectives, methodology, and potential implications of research using CFD and limited experimental data to develop new heat transfer and pressure drop correlations for plain, offset strip, and wavy fins, which are common in applications like cryogenics and aerospace. These new correlations could provide more accurate and broadly applicable insights for heat exchanger design compared to existing correlations.
This report details the design of a shell and tube heat exchanger to cool liquid propylene from 27°C to 15°C using chilled water at 5°C. Thermal and geometric properties are calculated using the Kern method. A one shell, two pass heat exchanger is selected with cooling water in the shell and propylene in the tubes. Material and energy balances are performed assuming a closed system. The design is modeled in Excel and Aspen for comparison. Cost analysis estimates a payback period of around 2 years, making the design viable.
1) The document analyzes heat transfer in a double pipe heat exchanger with helical tape inserts in the annulus of the inner pipe using computational fluid dynamics (CFD).
2) A 3D model is developed and simulations are run using the SST k-ω turbulent model to analyze how helical tape inserts influence heat transfer and pressure drop at different pitch lengths and Reynolds numbers.
3) The results show that helical tape inserts increase the heat transfer rate but also increase pressure drop due to flow disruption. Nusselt number and friction factor are found to correlate well with Reynolds number for enhancing heat transfer.
This document summarizes a student project analyzing the effectiveness of different fin designs on a CPU heatsink. It includes the design of a base heatsink model with 30 fins and details simulations varying the number of fins, fin height, and rotation speed. The results show that increasing the number of fins from 30 to 50 lowers the maximum surface temperature by 5.4°C, while further increases do not impact temperature as much.
AN EXPERIMENTAL STUDY OF EXERGY IN A CORRUGATED PLATE HEAT EXCHANGERIAEME Publication
In the present work an attempt has been made to investigate the performance of a 3 channel 1-1 pass, corrugated plate heat exchanger. The plates had sinusoidal wavy surfaces with corrugation angle of 450. Hot water at different inlet temperature ranging from 400C to 600C was made to flow in the central channel to get cooled by water in the outer channels.
International Journal of Engineering Research and DevelopmentIJERD Editor
Electrical, Electronics and Computer Engineering,
Information Engineering and Technology,
Mechanical, Industrial and Manufacturing Engineering,
Automation and Mechatronics Engineering,
Material and Chemical Engineering,
Civil and Architecture Engineering,
Biotechnology and Bio Engineering,
Environmental Engineering,
Petroleum and Mining Engineering,
Marine and Agriculture engineering,
Aerospace Engineering.
DESIGN, ANALYSIS AND PERFORMANCE INVESTIGATION OF HEAT EXTRACTION UNIT USING ...Journal For Research
Over the last years, there has been growing interest in applying new technologies to improve the heat transfer from the various heat sources such as geothermal energy, power plants, diesel engines, automobiles and other industrial heat-generating process. The heat transfer enhancement by means of extended surface type heat exchanger is well established technology and at present being adopted by most of the waste heat recovery system. Different types of heat transfer enhancement techniques using fins are available in extended surface type heat exchanger but each of this technique having different heat transfer enhancement ratio. Different researchers have analyzed the effect of fin geometry and combination of fins on heat transfer enhancement technique. In present research, find out the effect of fins on heat transfer augmentation or heat transfer coefficient for extracting heat from various waste heat sources.
Comparison of Experimental and DELTA-EC Results on performance of Thermoacous...IRJET Journal
This document compares the experimental and theoretical (DELTA-EC model) results of a thermoacoustic refrigerator's performance under different operating conditions. The refrigerator was tested experimentally for heating loads ranging from 2-10 watts, drive ratios of 1.6-2%, and frequencies of 200-600 Hz. The experimental temperatures and theoretical DELTA-EC temperatures showed similar trends but the experimental results deviated by about 26% due to viscous effects, discontinuities, turbulence, and heat losses not accounted for in the model. The highest temperature difference was obtained experimentally at 2 watts, 400 Hz, and 2% drive ratio.
Analysis of Double Pipe Heat Exchanger With Helical FinsIRJET Journal
This document analyzes a double pipe heat exchanger with helical fins through computational fluid dynamics (CFD). It aims to study the flow and temperature fields inside the tubes for different helical fin angles. The geometry of the double pipe heat exchanger is modeled in CATIA V5 and meshed in Hypermesh. CFD simulations are performed in ANSYS Fluent to analyze the flow and temperature distributions for fin angles of 0, 5, 10, 15, 20, and 25 degrees. The results determine that heat transfer rate and overall heat transfer coefficient increase with helical fins compared to a smooth tube, with fins providing additional surface area to enhance heat transfer.
EVALUATING MATHEMATICAL HEAT TRANSFER EFFECTIVENESS EQUATIONS USING CFD TECHN...AEIJjournal2
Mathematical heat transfer equations for finned double pipe heat exchangers based on experimental work
carried out in the 1970s can be programmed in a spreadsheet for repetitive use. Thus avoiding CFD
analysis which can be time consuming and costly. However, it is important that such mathematical
equations be evaluated for their accuracy. This paper uses CFD methods in evaluating the accuracy of
mathematical equations. Several models were created with varying; geometry, flue gas entry temperature,
and flow rates. The analysis should provide designers and manufacturers a judgment on the expected level
of accuracy when using mathematical modelling methodology. This paper simultaneously identifies best
practices in carrying out such CFD analysis.
EVALUATING MATHEMATICAL HEAT TRANSFER EFFECTIVENESS EQUATIONS USING CFD TECHN...AEIJjournal2
this analysis has shown that although mathematical equations are effective and simple tools in producing results, the results may not reflect the actual physical conditions. The analysis showed that theexhaust gas temperature outlet of a double pipe heat exchanger is actually higher than what were calculated using mathematical equations, and therefore, more heat energy is available for recapturing. k-epsilon RNG turbulence model was found to be the most suitable method in analyzing heat transfer in a finned double pipe heat exchanger.
an experiment on a co2 air conditioning system with copper heat exchangersINFOGAIN PUBLICATION
This document presents an experiment on a CO2 air conditioning system using copper heat exchangers. Testing showed that a conventional compressor is not suitable for high CO2 pressures and achieved a low COP of 0.3. A CO2 compressor allowed the system to run as a saturated cycle, achieving a COP of 3.07 at an evaporator temperature of 10°C, comparable to commercial systems. Thermodynamic parameters were measured and the cycle was shown to follow refrigeration principles, though pressure drops meant processes were quasi-isothermal and isobaric.
The document describes the design and performance analysis of an absorption heat transformer (AHT) using the first law of thermodynamics. The AHT uses industrial waste heat at 90°C to enhance the temperature in the absorber. The COP of the 2kW system is 0.4528 while the Carnot COP is 0.75. The absorber, generator, condenser, and evaporator are designed as shell and tube heat exchangers, while the solution heat exchanger is designed as a single pass annular tube heat exchanger. Equations for heat and mass transfer, circulation factor, COP, and heat exchanger design are presented to model and size the components of the AHT.
Enhancing Heat Transfer Efficiency: Nanofluid Integration in Diverse Systems ...IRJET Journal
This document discusses research on enhancing heat transfer efficiency through the integration of nanofluids in various systems and coiled heat exchangers. It investigates the effects of nanofluids on cooling towers, car radiators, refrigeration systems, and shell and helical coiled tube heat exchangers. The study models a double helix coiled tube heat exchanger using computational fluid dynamics and compares its performance when water and nanofluids are used. Nanofluids with 0.75% volume fraction and added surfactants for stability are tested. The results are analyzed based on heat transfer rate, effectiveness, and other thermal properties to evaluate the potential advantages of using hybrid nanofluids in coiled heat exchangers
IRJET- Numerical Investigation of Heat Transfer Enhancement in Circular Pipe ...IRJET Journal
1. The document numerically investigates heat transfer enhancement in a circular pipe with various rib geometries, including flat, conical, and right angle ribs.
2. It uses computational fluid dynamics to model water flow through the pipe with Reynolds numbers from 5000 to 60000 and a constant heat flux of 50 W/cm2 applied to the pipe surface.
3. The results show that ribs on the inside of the pipe enhance turbulence in the flow and produce recirculation, disturbing the thermal boundary layer and increasing the rate of heat transfer through the pipe.
Numerical Study of Entropy Generation in an Irreversible SolarPowered Absorpt...inventionjournals
The ideal three-heat-reservoir (THR) model for absorption refrigeration cycles is extended to include external and internal irreversibilities. Three empirical functions are used to model the internal entropy generation of the cycle. The parameters of these functions are estimated by fitting data obtained by simulation to the predictions of the THR model. The THR model using a linear function or a logarithmic function for the internal entropy generation is able to reproduce performance data for absorption systems with good accuracy
Similar to Performance prediction of a thermal system using Artificial Neural Networks (20)
A Novel Method for Prevention of Bandwidth Distributed Denial of Service AttacksIJERD Editor
Distributed Denial of Service (DDoS) Attacks became a massive threat to the Internet. Traditional
Architecture of internet is vulnerable to the attacks like DDoS. Attacker primarily acquire his army of Zombies,
then that army will be instructed by the Attacker that when to start an attack and on whom the attack should be
done. In this paper, different techniques which are used to perform DDoS Attacks, Tools that were used to
perform Attacks and Countermeasures in order to detect the attackers and eliminate the Bandwidth Distributed
Denial of Service attacks (B-DDoS) are reviewed. DDoS Attacks were done by using various Flooding
techniques which are used in DDoS attack.
The main purpose of this paper is to design an architecture which can reduce the Bandwidth
Distributed Denial of service Attack and make the victim site or server available for the normal users by
eliminating the zombie machines. Our Primary focus of this paper is to dispute how normal machines are
turning into zombies (Bots), how attack is been initiated, DDoS attack procedure and how an organization can
save their server from being a DDoS victim. In order to present this we implemented a simulated environment
with Cisco switches, Routers, Firewall, some virtual machines and some Attack tools to display a real DDoS
attack. By using Time scheduling, Resource Limiting, System log, Access Control List and some Modular
policy Framework we stopped the attack and identified the Attacker (Bot) machines
Hearing loss is one of the most common human impairments. It is estimated that by year 2015 more
than 700 million people will suffer mild deafness. Most can be helped by hearing aid devices depending on the
severity of their hearing loss. This paper describes the implementation and characterization details of a dual
channel transmitter front end (TFE) for digital hearing aid (DHA) applications that use novel micro
electromechanical- systems (MEMS) audio transducers and ultra-low power-scalable analog-to-digital
converters (ADCs), which enable a very-low form factor, energy-efficient implementation for next-generation
DHA. The contribution of the design is the implementation of the dual channel MEMS microphones and powerscalable
ADC system.
Influence of tensile behaviour of slab on the structural Behaviour of shear c...IJERD Editor
-A composite beam is composed of a steel beam and a slab connected by means of shear connectors
like studs installed on the top flange of the steel beam to form a structure behaving monolithically. This study
analyzes the effects of the tensile behavior of the slab on the structural behavior of the shear connection like slip
stiffness and maximum shear force in composite beams subjected to hogging moment. The results show that the
shear studs located in the crack-concentration zones due to large hogging moments sustain significantly smaller
shear force and slip stiffness than the other zones. Moreover, the reduction of the slip stiffness in the shear
connection appears also to be closely related to the change in the tensile strain of rebar according to the increase
of the load. Further experimental and analytical studies shall be conducted considering variables such as the
reinforcement ratio and the arrangement of shear connectors to achieve efficient design of the shear connection
in composite beams subjected to hogging moment.
Gold prospecting using Remote Sensing ‘A case study of Sudan’IJERD Editor
Gold has been extracted from northeast Africa for more than 5000 years, and this may be the first
place where the metal was extracted. The Arabian-Nubian Shield (ANS) is an exposure of Precambrian
crystalline rocks on the flanks of the Red Sea. The crystalline rocks are mostly Neoproterozoic in age. ANS
includes the nations of Israel, Jordan. Egypt, Saudi Arabia, Sudan, Eritrea, Ethiopia, Yemen, and Somalia.
Arabian Nubian Shield Consists of juvenile continental crest that formed between 900 550 Ma, when intra
oceanic arc welded together along ophiolite decorated arc. Primary Au mineralization probably developed in
association with the growth of intra oceanic arc and evolution of back arc. Multiple episodes of deformation
have obscured the primary metallogenic setting, but at least some of the deposits preserve evidence that they
originate as sea floor massive sulphide deposits.
The Red Sea Hills Region is a vast span of rugged, harsh and inhospitable sector of the Earth with
inimical moon-like terrain, nevertheless since ancient times it is famed to be an abode of gold and was a major
source of wealth for the Pharaohs of ancient Egypt. The Pharaohs old workings have been periodically
rediscovered through time. Recent endeavours by the Geological Research Authority of Sudan led to the
discovery of a score of occurrences with gold and massive sulphide mineralizations. In the nineties of the
previous century the Geological Research Authority of Sudan (GRAS) in cooperation with BRGM utilized
satellite data of Landsat TM using spectral ratio technique to map possible mineralized zones in the Red Sea
Hills of Sudan. The outcome of the study mapped a gossan type gold mineralization. Band ratio technique was
applied to Arbaat area and a signature of alteration zone was detected. The alteration zones are commonly
associated with mineralization. The alteration zones are commonly associated with mineralization. A filed check
confirmed the existence of stock work of gold bearing quartz in the alteration zone. Another type of gold
mineralization that was discovered using remote sensing is the gold associated with metachert in the Atmur
Desert.
Reducing Corrosion Rate by Welding DesignIJERD Editor
This document summarizes a study on reducing corrosion rates in steel through welding design. The researchers tested different welding groove designs (X, V, 1/2X, 1/2V) and preheating temperatures (400°C, 500°C, 600°C) on ferritic malleable iron samples. Testing found that X and V groove designs with 500°C and 600°C preheating had corrosion rates of 0.5-0.69% weight loss after 14 days, compared to 0.57-0.76% for 400°C preheating. Higher preheating reduced residual stresses which decreased corrosion. Residual stresses were 1.7 MPa for optimal X groove and 600°C
Router 1X3 – RTL Design and VerificationIJERD Editor
Routing is the process of moving a packet of data from source to destination and enables messages
to pass from one computer to another and eventually reach the target machine. A router is a networking device
that forwards data packets between computer networks. It is connected to two or more data lines from different
networks (as opposed to a network switch, which connects data lines from one single network). This paper,
mainly emphasizes upon the study of router device, it‟s top level architecture, and how various sub-modules of
router i.e. Register, FIFO, FSM and Synchronizer are synthesized, and simulated and finally connected to its top
module.
Active Power Exchange in Distributed Power-Flow Controller (DPFC) At Third Ha...IJERD Editor
This paper presents a component within the flexible ac-transmission system (FACTS) family, called
distributed power-flow controller (DPFC). The DPFC is derived from the unified power-flow controller (UPFC)
with an eliminated common dc link. The DPFC has the same control capabilities as the UPFC, which comprise
the adjustment of the line impedance, the transmission angle, and the bus voltage. The active power exchange
between the shunt and series converters, which is through the common dc link in the UPFC, is now through the
transmission lines at the third-harmonic frequency. DPFC multiple small-size single-phase converters which
reduces the cost of equipment, no voltage isolation between phases, increases redundancy and there by
reliability increases. The principle and analysis of the DPFC are presented in this paper and the corresponding
simulation results that are carried out on a scaled prototype are also shown.
Mitigation of Voltage Sag/Swell with Fuzzy Control Reduced Rating DVRIJERD Editor
Power quality has been an issue that is becoming increasingly pivotal in industrial electricity
consumers point of view in recent times. Modern industries employ Sensitive power electronic equipments,
control devices and non-linear loads as part of automated processes to increase energy efficiency and
productivity. Voltage disturbances are the most common power quality problem due to this the use of a large
numbers of sophisticated and sensitive electronic equipment in industrial systems is increased. This paper
discusses the design and simulation of dynamic voltage restorer for improvement of power quality and
reduce the harmonics distortion of sensitive loads. Power quality problem is occurring at non-standard
voltage, current and frequency. Electronic devices are very sensitive loads. In power system voltage sag,
swell, flicker and harmonics are some of the problem to the sensitive load. The compensation capability
of a DVR depends primarily on the maximum voltage injection ability and the amount of stored
energy available within the restorer. This device is connected in series with the distribution feeder at
medium voltage. A fuzzy logic control is used to produce the gate pulses for control circuit of DVR and the
circuit is simulated by using MATLAB/SIMULINK software.
Study on the Fused Deposition Modelling In Additive ManufacturingIJERD Editor
Additive manufacturing process, also popularly known as 3-D printing, is a process where a product
is created in a succession of layers. It is based on a novel materials incremental manufacturing philosophy.
Unlike conventional manufacturing processes where material is removed from a given work price to derive the
final shape of a product, 3-D printing develops the product from scratch thus obviating the necessity to cut away
materials. This prevents wastage of raw materials. Commonly used raw materials for the process are ABS
plastic, PLA and nylon. Recently the use of gold, bronze and wood has also been implemented. The complexity
factor of this process is 0% as in any object of any shape and size can be manufactured.
Spyware triggering system by particular string valueIJERD Editor
This computer programme can be used for good and bad purpose in hacking or in any general
purpose. We can say it is next step for hacking techniques such as keylogger and spyware. Once in this system if
user or hacker store particular string as a input after that software continually compare typing activity of user
with that stored string and if it is match then launch spyware programme.
A Blind Steganalysis on JPEG Gray Level Image Based on Statistical Features a...IJERD Editor
This paper presents a blind steganalysis technique to effectively attack the JPEG steganographic
schemes i.e. Jsteg, F5, Outguess and DWT Based. The proposed method exploits the correlations between
block-DCTcoefficients from intra-block and inter-block relation and the statistical moments of characteristic
functions of the test image is selected as features. The features are extracted from the BDCT JPEG 2-array.
Support Vector Machine with cross-validation is implemented for the classification.The proposed scheme gives
improved outcome in attacking.
Secure Image Transmission for Cloud Storage System Using Hybrid SchemeIJERD Editor
- Data over the cloud is transferred or transmitted between servers and users. Privacy of that
data is very important as it belongs to personal information. If data get hacked by the hacker, can be
used to defame a person’s social data. Sometimes delay are held during data transmission. i.e. Mobile
communication, bandwidth is low. Hence compression algorithms are proposed for fast and efficient
transmission, encryption is used for security purposes and blurring is used by providing additional
layers of security. These algorithms are hybridized for having a robust and efficient security and
transmission over cloud storage system.
Application of Buckley-Leverett Equation in Modeling the Radius of Invasion i...IJERD Editor
A thorough review of existing literature indicates that the Buckley-Leverett equation only analyzes
waterflood practices directly without any adjustments on real reservoir scenarios. By doing so, quite a number
of errors are introduced into these analyses. Also, for most waterflood scenarios, a radial investigation is more
appropriate than a simplified linear system. This study investigates the adoption of the Buckley-Leverett
equation to estimate the radius invasion of the displacing fluid during waterflooding. The model is also adopted
for a Microbial flood and a comparative analysis is conducted for both waterflooding and microbial flooding.
Results shown from the analysis doesn’t only records a success in determining the radial distance of the leading
edge of water during the flooding process, but also gives a clearer understanding of the applicability of
microbes to enhance oil production through in-situ production of bio-products like bio surfactans, biogenic
gases, bio acids etc.
Gesture Gaming on the World Wide Web Using an Ordinary Web CameraIJERD Editor
- Gesture gaming is a method by which users having a laptop/pc/x-box play games using natural or
bodily gestures. This paper presents a way of playing free flash games on the internet using an ordinary webcam
with the help of open source technologies. Emphasis in human activity recognition is given on the pose
estimation and the consistency in the pose of the player. These are estimated with the help of an ordinary web
camera having different resolutions from VGA to 20mps. Our work involved giving a 10 second documentary to
the user on how to play a particular game using gestures and what are the various kinds of gestures that can be
performed in front of the system. The initial inputs of the RGB values for the gesture component is obtained by
instructing the user to place his component in a red box in about 10 seconds after the short documentary before
the game is finished. Later the system opens the concerned game on the internet on popular flash game sites like
miniclip, games arcade, GameStop etc and loads the game clicking at various places and brings the state to a
place where the user is to perform only gestures to start playing the game. At any point of time the user can call
off the game by hitting the esc key and the program will release all of the controls and return to the desktop. It
was noted that the results obtained using an ordinary webcam matched that of the Kinect and the users could
relive the gaming experience of the free flash games on the net. Therefore effective in game advertising could
also be achieved thus resulting in a disruptive growth to the advertising firms.
Hardware Analysis of Resonant Frequency Converter Using Isolated Circuits And...IJERD Editor
-LLC resonant frequency converter is basically a combo of series as well as parallel resonant ckt. For
LCC resonant converter it is associated with a disadvantage that, though it has two resonant frequencies, the
lower resonant frequency is in ZCS region[5]. For this application, we are not able to design the converter
working at this resonant frequency. LLC resonant converter existed for a very long time but because of
unknown characteristic of this converter it was used as a series resonant converter with basically a passive
(resistive) load. . Here, it was designed to operate in switching frequency higher than resonant frequency of the
series resonant tank of Lr and Cr converter acts very similar to Series Resonant Converter. The benefit of LLC
resonant converter is narrow switching frequency range with light load[6] . Basically, the control ckt plays a
very imp. role and hence 555 Timer used here provides a perfect square wave as the control ckt provides no
slew rate which makes the square wave really strong and impenetrable. The dead band circuit provides the
exclusive dead band in micro seconds so as to avoid the simultaneous firing of two pairs of IGBT’s where one
pair switches off and the other on for a slightest period of time. Hence, the isolator ckt here is associated with
each and every ckt used because it acts as a driver and an isolation to each of the IGBT is provided with one
exclusive transformer supply[3]. The IGBT’s are fired using the appropriate signal using the previous boards
and hence at last a high frequency rectifier ckt with a filtering capacitor is used to get an exact dc
waveform .The basic goal of this particular analysis is to observe the wave forms and characteristics of
converters with differently positioned passive elements in the form of tank circuits.
Simulated Analysis of Resonant Frequency Converter Using Different Tank Circu...IJERD Editor
LLC resonant frequency converter is basically a combo of series as well as parallel resonant ckt. For
LCC resonant converter it is associated with a disadvantage that, though it has two resonant frequencies, the
lower resonant frequency is in ZCS region [5]. For this application, we are not able to design the converter
working at this resonant frequency. LLC resonant converter existed for a very long time but because of
unknown characteristic of this converter it was used as a series resonant converter with basically a passive
(resistive) load. . Here, it was designed to operate in switching frequency higher than resonant frequency of the
series resonant tank of Lr and Cr converter acts very similar to Series Resonant Converter. The benefit of LLC
resonant converter is narrow switching frequency range with light load[6] . Basically, the control ckt plays a
very imp. role and hence 555 Timer used here provides a perfect square wave as the control ckt provides no
slew rate which makes the square wave really strong and impenetrable. The dead band circuit provides the
exclusive dead band in micro seconds so as to avoid the simultaneous firing of two pairs of IGBT’s where one
pair switches off and the other on for a slightest period of time. Hence, the isolator ckt here is associated with
each and every ckt used because it acts as a driver and an isolation to each of the IGBT is provided with one
exclusive transformer supply[3]. The IGBT’s are fired using the appropriate signal using the previous boards
and hence at last a high frequency rectifier ckt with a filtering capacitor is used to get an exact dc
waveform .The basic goal of this particular analysis is to observe the wave forms and characteristics of
converters with differently positioned passive elements in the form of tank circuits. The supported simulation
is done through PSIM 6.0 software tool
Amateurs Radio operator, also known as HAM communicates with other HAMs through Radio
waves. Wireless communication in which Moon is used as natural satellite is called Moon-bounce or EME
(Earth -Moon-Earth) technique. Long distance communication (DXing) using Very High Frequency (VHF)
operated amateur HAM radio was difficult. Even with the modest setup having good transceiver, power
amplifier and high gain antenna with high directivity, VHF DXing is possible. Generally 2X11 YAGI antenna
along with rotor to set horizontal and vertical angle is used. Moon tracking software gives exact location,
visibility of Moon at both the stations and other vital data to acquire real time position of moon.
“MS-Extractor: An Innovative Approach to Extract Microsatellites on „Y‟ Chrom...IJERD Editor
Simple Sequence Repeats (SSR), also known as Microsatellites, have been extensively used as
molecular markers due to their abundance and high degree of polymorphism. The nucleotide sequences of
polymorphic forms of the same gene should be 99.9% identical. So, Microsatellites extraction from the Gene is
crucial. However, Microsatellites repeat count is compared, if they differ largely, he has some disorder. The Y
chromosome likely contains 50 to 60 genes that provide instructions for making proteins. Because only males
have the Y chromosome, the genes on this chromosome tend to be involved in male sex determination and
development. Several Microsatellite Extractors exist and they fail to extract microsatellites on large data sets of
giga bytes and tera bytes in size. The proposed tool “MS-Extractor: An Innovative Approach to extract
Microsatellites on „Y‟ Chromosome” can extract both Perfect as well as Imperfect Microsatellites from large
data sets of human genome „Y‟. The proposed system uses string matching with sliding window approach to
locate Microsatellites and extracts them.
Importance of Measurements in Smart GridIJERD Editor
- The need to get reliable supply, independence from fossil fuels, and capability to provide clean
energy at a fixed and lower cost, the existing power grid structure is transforming into Smart Grid. The
development of a smart energy distribution grid is a current goal of many nations. A Smart Grid should have
new capabilities such as self-healing, high reliability, energy management, and real-time pricing. This new era
of smart future grid will lead to major changes in existing technologies at generation, transmission and
distribution levels. The incorporation of renewable energy resources and distribution generators in the existing
grid will increase the complexity, optimization problems and instability of the system. This will lead to a
paradigm shift in the instrumentation and control requirements for Smart Grids for high quality, stable and
reliable electricity supply of power. The monitoring of the grid system state and stability relies on the
availability of reliable measurement of data. In this paper the measurement areas that highlight new
measurement challenges, development of the Smart Meters and the critical parameters of electric energy to be
monitored for improving the reliability of power systems has been discussed.
Study of Macro level Properties of SCC using GGBS and Lime stone powderIJERD Editor
The document summarizes a study on the use of ground granulated blast furnace slag (GGBS) and limestone powder to replace cement in self-compacting concrete (SCC). Tests were conducted on SCC mixes with 0-50% replacement of cement with GGBS and 0-20% replacement with limestone powder. The results showed that replacing 30% of cement with GGBS and 15% with limestone powder produced SCC with the highest compressive strength of 46MPa, meeting fresh property requirements. The study concluded that this ternary blend of cement, GGBS and limestone powder can improve SCC properties while reducing costs.
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Data Communication and Computer Networks Management System Project Report.pdfKamal Acharya
Networking is a telecommunications network that allows computers to exchange data. In
computer networks, networked computing devices pass data to each other along data
connections. Data is transferred in the form of packets. The connections between nodes are
established using either cable media or wireless media.
Performance prediction of a thermal system using Artificial Neural Networks
1. International Journal of Engineering Research and Development
e-ISSN: 2278-067X, p-ISSN: 2278-800X, www.ijerd.com
Volume 11, Issue 07 (July 2015), PP.16-22
16
Performance prediction of a thermal system using Artificial
Neural Networks
M.Srinivasa Rao1
, B.Bharath kumar2
1
Professor, Department of mechanical engineering, GMRIT, Rajam, Srikakulam.
2
M.Tech Student, Department of mechanical engineering, GMRIT, Rajam, Srikakulam.
Abstract:- Condenser is a device in which heat is transferred from one medium to another across a solid
surface. The performance of condenser deteriorates with time due to fouling on the heat transfer surface. It is
necessary to assess periodically the condenser performance, in order to maintain at high efficiency level.
Industries follow adopted practices to monitor but it is limited to some degree. In this paper, performance
monitoring system for a condenser is developed using artificial neural networks (ANNs). Experiments are
conducted based on full factorial design of experiments to develop a model using the parameters such as
temperatures and flow rates. ANN model for overall heat transfer coefficient of a design/ clean condenser
system is developed using a feed forward back propagation neural network and trained. The developed model is
validated and tested by comparing the results with the experimental results. This model is used to assess the
performance of condenser with the real/fouled system. The performance degradation is expressed using fouling
factor (FF), which is derived from the overall heat transfer coefficient of design system and real system. It
supports the system to improve the performance by asset utilization, energy efficient and cost reduction in terms
of production loss.
Keywords:- Condenser; Full factorial design of experiments(DOE):Artificial neural networks (ANNs); overall
heat transfer coefficient; Fouling factor(FF).
I. INTRODUCTION
A condenser has two main advantages: The primary advantage is to maintain a low pressure
(atmosphere or below atmosphere pressure) so as to obtain the maximum possible energy from steam and thus
to secure a high efficiency, The secondary advantage is to supply pure feed water to the hot well, from where it
is pumped back to the boiler.
It is recommended the (ANN) can be used to predict the performance of thermal system in engineering
applications, such as modelling condenser for heat transfer analysis. Afterwards, ANN resulted used to find
thermal parameters (convection heat transfer coefficient of water side hw and steam flow rate m s) based on
software program built by Matlab language[1], The prediction of fouling in condenser is heavily influenced by
the periodic fouling process and dynamics change of the operational parameters, to deal with this problem, a
novel approach based on fuzzy stage identification and Chebyshev neural network is proposed[2], This model is
used to assess the performance of heat exchanger with the real/fouled system. The performance degradation is
expressed using fouling factor (FF), which is derived from the overall heat transfer coefficient of design system
and real system[3], The multi-input multi-output (MIMO) neural network is separated into multi-input single-
output (MISO) neural networks for training. Afterwards, the trained MISO neural networks are combined into a
MIMO neural network, which indicates that the number of training data sets is determined by the biggest MISO
neural network not the whole MIMO network [4]. The author present and discuss a stochastic approach to the
analysis of fouling models. In view of the performance indicator (U/Uc) of the heat exchangers, a maintenance
strategy for planned maintenance schedules is presented. Various scenarios of reliability based maintenance
strategy are introduced. The strategy is explained in terms of the scatter parameter (α) of the time to fouling
distribution corresponding to a critical level of fouling, and the risk factor (p) representing the probability of
tubes being fouled to a critical level after which a cleaning cycle is needed[5]. The author presents an analytical
and computational modelling of the effect of the space surrounding the condenser of a household refrigerator on
the rejected heat. The driving force for rejecting the heat carried by the refrigerant from the interior of a
refrigerator is the temperature difference between the condenser outer surface and surrounding air[6]. Due to the
fouling deposit on the heat transfer surfaces, the thermal resistance between refrigerant and water gradually
increases. The fouling resistance depends on several factors such as heat exchanger geometry, heat flux, water
quality and water flow rates [7].
2. Performance prediction of a thermal system using Artificial Neural Networks
17
From the above literature survey, it is identified that the performance prediction of condenser is analysed by
applying various techniques which involves complexity and difficult procedures. To mitigate these limitations,
In this paper ANN is used in a simpler way to predict the performance of a condenser as follows.
II. PROBLEM DEFINITION
In this paper, a monitoring system is developed for a condenser using measurements namely the
temperatures and flow rates of the hot and cold fluid .Neural network system is developed to investigate the
performance of condenser. ANN is applied to model the heat exchanger with experimental data. The input
parameters to develop a model for condenser are inlet temperature and flow rate of shell and tube side fluids
and output is overall heat transfer coefficient (UDesign). The overall heat transfer coefficient of real/fouled
system (UReal) is calculated using online measured values such as inlet temperature, outlet temperature and
flow rate of shell and tube side fluids. The condenser performance is assessed by comparing the results of
clean/design and fouled/real system. Any deviation from the result of design/clean system indicates that the
performance is degraded due to fouling. Its degree is derived from fouling factor (FF) using UDesign and UReal.
III. CASE STUDY
In this present work, Nagarjuna agrichem taken as a case study. It is located in chilakapalem,
srikakulam district, Andhra Pradesh, India. Nagarjuna agrichem which produces the pesticides, insecticides,
fungicides, etc, the outlet from the reactor containing hot gases and vapors will be sent to tube side of the
condenser, where as cold water enters the condenser at shell side. Hot vapors from reactor will condense by
rejecting heat to water. The condensate will be sent to collecting tank. The remaining undissolved gases in the
condenser will be passed over to vacuum pump which drains them out to atmosphere. Both vapour and water
flow in counter current direction so as to attain maximum heat transfer rate.
A. Condenser setup in industry
Figure 1. Condenser setup in industry
B. Specifications of condenser
Condenser Type Shell and Tube in Counter current mode
Shell material SS 316
Tube material Copper
Shell diameter 360mm
Tube length 3000 mm
Number of Tubes 144
Tube Outer Diameter (OD) 22 mm
Tube Inner Diameter (ID) 19.05 mm
Baffle no‟s 6
3. Performance prediction of a thermal system using Artificial Neural Networks
18
C. Data obtained from industry
Three process parameters namely hot vapor inlet temperature, cold water flow rate and hot vapor flow rate were
selected and their data was taken at 3 different levels.
Parameter Level1 Level2 Level3
Cold water Flow rate(LPH) 350 375 400
Hot vapor Flow rate(LPH) 230 250 270
Hot vapor inlet
temperature(°C)
56 59 62
D. Taguchi method
Taguchi method is a statistical method developed by Taguchi and Konishi. It involves identification of
proper Orthogonal Arrays (OA) are used to conduct a set of experiments. L27 Orthogonal Arrays (OA) is used
in this work. Full factorial design of experiments (DOE) is used and their combinations of process parameters
such as temperatures and flow rates were used for calculations Experimental design using full factorial design of
experiments and their outputs [8].
E. Equations used and methodology of calculations
The performance of the condenser is assessed by computing overall heat transfer coefficient. The overall heat
transfer coefficient is calculated using log mean temperature difference (LMTD) approach because the inlet
temperature, outlet temperature and flow rate of the cold and hot water are known. The overall heat transfer
coefficient of condenser is calculated by using below equations.
Qh = mh Cph (Thi – Tho) in kW (1)
(or)
Qc = mc Cpc (Tco – Tci) in kW (2)
where
Qh - Heat transfer rate of hot vapor side
Qc - Heat transfer rate of cold water side
mh - Mass flow rate of hot vapor in kg/hr
mc - Mass flow rate of cold water in kg/hr
Cph – Specific heat capacity of hot vapor in kJ/kgK
Cpc – Specific heat capacity of hot water in kJ/kgK
Thi – Hot vapor inlet temperature in °C
Tho - Hot vapor outlet temperature in °C
Tco - Cold water inlet temperature in °C
Tci - Cold water outlet temperature in °C
A - Heat transfer Area in m2.
LMTD for Counter current flow =
((Thi-Tco)-(Tho-Tci)) / ln ((Thi-Tco) / (Tho-Tci)) (3)
U = [Qh or Qc] / [A*LMTD] in W/m2.°C (4)
Where U is Overall Heat transfer Co-efficient.
Initially the heat transfer rate (Q) of the water or vapor was calculated based on secondary
measurements such as temperatures and flow rates using equation (1) or (2). Then the heat transfer area of the
heat exchanger (A) was calculated based on the geometrical parameters. LMTD for counter-current flow of
vapor and water was computed with inlet and outlet temperatures of cold and hot water using equation (3).
Based on the calculated values of Q, A, and LMTD the overall heat transfer coefficient was calculated using
equation (4). The overall heat transfer coefficient of design/clean condenser is computed and it varies from 4.21-
7.31 w/m2
k.
4. Performance prediction of a thermal system using Artificial Neural Networks
19
IV. DESIGN AND DEVELOPMENT OF PERFORMANCE ASSESSMENT SYSTEM FOR
CONDENSER USING ANN
A. Design of performance assessment system
In this an ANN is used to develop the model for predicting the overall heat transfer coefficient
(UDesign) of the design system using secondary measurements temperature and flow rates. Inputs of the
developed network were temperature of hot vapor inlet Thi, flow rate of cold water Fci and flow rate of hot
vapor Fhi and output was UDesign. Data acquired from the design of experiments were used for training,
validation and testing the ANN model. Heat transfer coefficient of real system (UReal) is derived using
secondary measurements such as Tci, Thi, Tco, Tho, Fci and Fhi.
This system imitate the real time system and used for performance assessment (fouling) of the system.
Measured values of Tci, Thi, Tco, Tho, Fci and Fhi are used to predict the value of UDesign and compute the
value of UReal.
FF value is computed with the predicted value of UDesign and the computed value of UReal. It
is used to identify the performance degradation or degree of fouling of the condenser. If the FF value is greater
than or equal to the set value (allowable) of design condenser, warning message will be given for cleaning or
maintenance of condenser.
B. NN model development
FF value is computed with the predicted value of UDesign and the computed value of UReal. It
is used to identify the performance degradation or degree of fouling of the condenser. If the FF value is greater
than or equal to the set value (allowable) of design condenser, warning message will be given for cleaning or
maintenance of condenser.
Figure 2. Topography of developed ANN Model (3-10-1) for UDesign
The network architecture or features such as number of neurons and layers are very important factors
that determine the functionality and generalization capability of the network. For the model, a standard
multilayer feed forward back propagation hierarchical neural network is designed with MATLAB NN Toolbox.
The networks consist of three layers: the input layer, hidden layer, and output layer. In order to determine the
number of hidden layers and neurons we go for trial and error method. The neural networks for UDesign has
three neurons in the input, corresponding to each of the three process input parameters Thi, Fci and Fhi and
one neuron in the output layer, corresponding to the process response UDesign. The topography of the ANN
model (3-10-1) for UDesign is shown in Figure 2. In this one hidden layer with ten neurons is found to be
most suitable for model development by trial and error method. For networks, linear transfer function „purelin‟
and tan sigmoid transfer function „tansig‟ is used in the output and hidden layer respectively. Industry data set
are used to train, validate and test the UDesign network. In this, nineteen data set are used for training, four
data set are used for validation and remaining four data set is used for testing the network. The training of
ANN for 19 input-output patterns has been carried using „trainlm‟ algorithm. The learning factors are set as
5. Performance prediction of a thermal system using Artificial Neural Networks
20
goal of 10
-10
and epochs of 1000. The variation of MSE during the training is shown in Figure 3 In the
present study, the desired MSE is achieved after 11 epochs.
Figure 3. Training graph of developed ANN model for UDesign
The trained ANN is initially tested by presenting 19 input patterns, which are employed for the
training purpose. For each input pattern, the predicted value of overall heat transfer coefficient is compared
with respective output data and absolute percentage error is compared, which is given as
% Absolute error=│(Yi,exp – Yi,pred)/(Yi,exp)│X100 (5)
where, Yi, exp is the measured value and
Yi, pred is the ANN predicted value of the response for i
th
trial.
The performance capability of network is examined based on the absolute error percentage between
the network predictions and the experimental values. It is found that the predicted and experimental values are
very fairly close to each other. The error of overall heat transfer coefficient for 19 input trials of training
patterns are 10.3%. Another way of measuring the performance of a trained network is by performing a
regression analysis between the network response and the corresponding targets. This is carried out by using
„postreg‟ function in MATLAB. The graphical output of „postreg‟ is shown in Figure 4 for UDesign. The
correlation coefficient (R) between the outputs and targets is a measure of how well the variation in the output
is explained by the targets. If R value is 1 then it indicates perfect correlation between the target (T) and
predicted outputs (A). In this case, the R value of the output overall heat transfer coefficient is 0.89685, it
indicates that the model had good correlation.
In validation, four new data set are used, which do not belong to the training data set. For this
validation data set, the overall heat transfer coefficient is predicted using the ANN model and then compared
with the actual (real) values. It is observed that predicted values of UDesign are very closer to the actual
values that are shown in Figure 4. It is also found that maximum absolute error of UDesign is 7.41 %. This
indicates that the model accuracy for predicting the process responses is adequate.
For testing, other four new data set are used which do not belong to the training and validation data set.
For this testing data set, the overall heat transfer coefficient is predicted using the ANN model and then
compared with the actual values. It is observed that predicted values of UDesign are very closer to the
actual values that are shown in Figure 4. It is also found that maximum absolute error of UDesign is 0.14%.
This indicates that the model for predicting the process responses is well adequate for generalization. NN
6. Performance prediction of a thermal system using Artificial Neural Networks
21
model for UDesign is developed to study the performance degradation by estimating the fouling of the
condenser.
Figure 4: Output value graph of developed ANN model for UDesign
F. Performance assessment
Condenser‟s performance will degrade with the time from design to real conditions. The rate at
which this will occur is dependent on the application of condensers. Fouling detection is able to present the
degradation of condenser performance, which is responsive for changes in the FF across the heat transfer
surface. Effective and majorly applied method for fouling detection is to compare the UDesign and UReal. It
cannot be measured directly and it uses the secondary measurements such as flow rates and temperatures as
inputs from the industrial data to estimate it.
From the measured values such as Tci, Thi, Tco, Tho, Fci and Fhi the performance of the condenser is
assessed. Thi, Fci and Fhi were used to predict the value of UDesign using developed ANN model. UReal value
is computed using LMTD approach with Tci, Thi, Tco, Tho, Fci and Fhi. The performance of condenser is
assessed by comparing the UReal value with UDesign value. The decrease in UReal value indicates the
degradation of performance by formation of fouling.
In this, performance degradation or fouling is estimated using FF approach and this will indicate the degree of
fouling. The degradation in performance is expressed by the FF, as calculated by the equation:
FF=[(1/UReal)-(1/UDesign)] (6)
The FF value of condenser is calculated using the equation (6). In design stage, the allowable Fouling
resistance i.e. FF is specified for all the condensers by manufacturer‟s to avoid frequent cleaning or
maintenance.
V. RESULTS AND DISCUSSIONS
The system initially predicts the UDesign value with ANN model and computes the UReal value
through the observed input values. We manually calculated the FF value using UReal and UDesign values. Based on
the FF value the system gives the information to the operator. The FF range for our industrial equipment is
0.0003-0.0008. From the results it is identified that the condenser performance is within the tolerance
value (set by field engineer/maintenance engineer) of FF, there is no need for maintenance If the performance
of the condenser is above the tolerance value of FF, it needs immediate maintenance or corrective action to
recover the heat transfer efficiency. This gives intimation to the operator for planning maintenance well ahead
to minimize operational disturbance due to unplanned shutdowns.
7. Performance prediction of a thermal system using Artificial Neural Networks
22
The advantage of this system is that it could be easily implemented in the industries to get
performance assessment/fouling effect by simple and effective manner. This gives comprehensive information
to field engineers for improving the performance of condenser by asset utilization, energy efficient and cost
reduction in terms of production loss and maintenance.
VI. CONCLUSION
In this work, Data were taken for a condenser with different flow rates of cold water and hot vapor,
and hot inlet temperature to assess the performance of the system. The data was incorporated into the
ANN model development. A feed forward neural networks model was developed to predict overall heat
transfer coefficient UDesign of the design condenser system and the model was trained, validated and tested
for generalization. Good agreement was identified between the predictive model results and the manually
calculated results. It was found that the maximum error of validation and testing data set for overall heat
transfer coefficient UDesign of the design system were 0.17 % and 7.41 % respectively. NN model was used
to predict the value UDesign and UReal was derived from measured values. FF is found from the predicted
UDesign and UReal value. From the estimated FF value, the performance degradation/fouling effect was
within the tolerance limit (margin). Based on the results, further it needs intelligent approach to do fouling
analysis and maintenance decisions.
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