The document describes a simulation of a Rocket Mass Heater Stove (RMHS) conducted using COMSOL Multiphysics. The objective was to analyze the correlation between high temperature and turbulence for clean burning inside the RMHS. The initial simulation modeled combustion within a cylinder representing the stove chamber. Preliminary results showed unrealistic temperature and airflow distributions. Refinements included stationary study, simplified geometry, and reduced mesh size. The final results indicated higher temperatures and airflows correlated better, but lacked turbulence modeling and full validation against empirical data. Further work was recommended to improve modeling of heat transfer and incorporate additional RMHS components and turbulence effects.
This document discusses the thermal design of a simple boiler. It presents the calculation procedures for boiler design, focusing on heat transfer modes, heat and mass balances, and a worked example. The key points are:
- Heat transfer in boilers occurs via conduction, convection, and radiation. Conduction is not considered in simple calculations.
- Heat and mass balance equations relate the heat input from fuel to the heat output via steam as well as accounting for air and flue gas flows.
- A worked example calculates furnace conditions like flue gas temperature for a methane-fueled boiler, assuming radiation is the only heat transfer mode in the furnace. Tube bank calculations then determine the exit gas
This document summarizes a CFD investigation of the effect of changing the angle of secondary air on NOx emissions in a 660 MW tangentially fired coal boiler. The study found that changing the angle of secondary air from horizontal to an inclined angle reduced NOx levels at the furnace outlet by 15%, from 166 ppm to 143 ppm. A CFD model was developed and validated against plant data to analyze the combustion and flow patterns with different secondary air parameters. The optimized secondary air configuration lowered NOx emissions through improved mixing and delayed ignition.
PyTeCK: A Python-based automatic testing package for chemical kinetic modelsOregon State University
Β
Combustion simulations require detailed chemical kinetic models to predict fuel oxidation, heat release, and pollutant emissions. These models are typically validated using qualitative rather than quantitative comparisons with limited sets of experimental data. This work introduces PyTeCK, an open-source Python-based package for automatic testing of chemical kinetic models. Given a model of interest, PyTeCK automatically parses experimental datasets encoded in a YAML format, validates the self-consistency of each dataset, and performs simulations for each experimental datapoint. It then reports a quantitative metric of the model's performance, based on the discrepancy between experimental and simulated values and weighted by experimental variance. The initial version of PyTeCK supports shock tube and rapid compression machine experiments that measure autoignition delay. PyTeCK relies on several packages in the SciPy stack and greater scientific Python ecosystem. In addition to providing an easy-to-use, automated tool for evaluating chemical kinetic model performance, a secondary objective of PyTeCK is to encourage greater openness and reproducibility in combustion research.
Design With Solid works Software and Planning Calculation Analysis of Fire Tu...IJRES Journal
Β
Steam boilers (boilers) is a closed vessel made of steel that is used to generate steam. In the modern era many industries such as household scale industries for the manufacture of oyster mushroom spawn to use aid as a supplier of steam boilers are used as a sterilization process baglog. Annually, the number of requests oyster mushroom spawn have been increases, so the boiler is very significant equipment to increase the number of baglog production as oyster mushroom growing media.To help to fulfill the small industryrequiremets for oyster mushroom nursery,plannedatype offire tubeboilerthatcanhelpthe availability ofsteam ina lowscalewithsteamoutputcapacity of70kg/ h, temperature120β, pressure1.5barandusingmaterialsLPGfuelas a source ofheatenergy.From the results of this design, fire tube boiler have efficiency of 0.934 % . The kettle body is made from asphalt drums pertamina with the Cold Rolled Steel materials. Used asphalt drums because of its availability in the market more easier to obtained easily and the dimensions of asphalt drum capable of holding for temperature and pressure have been determined . As for the pipe material using Carbon Steel Tubing Boilers ASME SA - 178A GRADE A / SA - 214 (Plain Carbon).
Mech 0036 exam 12 13 with answers (revision)Mostafa Tamish
Β
This document appears to be a past exam paper and marking scheme for a Thermal Power Plant and Heat Transfer course. It contains 6 questions testing various concepts related to thermodynamics, heat transfer, steam power plants, gas turbines, and refrigeration. For each question, it provides the question prompt, relevant figures or tables, and a detailed multi-part solution and marking scheme. The questions cover topics such as spark ignition engines, Rankine cycles, heat exchangers, radiation heat transfer, and gas turbine cycles.
The document analyzes the thermodynamic performance of a lithium bromide (LiBr) and water based vapor absorption air conditioning system that utilizes waste exhaust heat from a diesel engine. The system consists of a generator, condenser, evaporator, absorber, and solution heat exchanger. The effects of varying the temperatures of these components on the system's coefficient of performance (COP) and exergy efficiency are examined. The results show that COP increases with higher evaporator temperature but decreases with higher condenser and absorber temperatures. Exergy analysis indicates the condenser and absorber have higher exergy losses than the generator and evaporator. A small-scale LiBr-water system can feasibly operate using exhaust heat from
Flame stabilisation in microcombustors Shyam Kumar
Β
Microcombustion involves combustion in devices with characteristic lengths smaller than 1 mm. It has applications in micro-thrusters and micro-air vehicles. Key challenges in microcombustion include low Reynolds and Peclet numbers, short residence times, increased heat transfer through conduction and radiation, and flame quenching due to increased surface area to volume ratios. Various microcombustor designs aim to address these issues through techniques like preheating reactants, insulating combustor walls, incorporating heat recirculation or catalytic combustion to improve stability. Stability is also influenced by parameters like flow velocity, wall conductivity, combustor geometry and choice of fuel.
The document discusses energy conservation through waste heat recovery and combined heat and power generation. It provides two case studies as examples. The first case study examines using waste heat from a diesel engine exhaust to generate steam and distilled water. The second case study compares the environmental and economic benefits of a combined heat and power system versus separate heat and power generation. Key topics covered include definitions of waste heat recovery and combined heat and power, types and sources of waste heat, and the environmental and financial benefits of combined heat and power systems.
This document discusses the thermal design of a simple boiler. It presents the calculation procedures for boiler design, focusing on heat transfer modes, heat and mass balances, and a worked example. The key points are:
- Heat transfer in boilers occurs via conduction, convection, and radiation. Conduction is not considered in simple calculations.
- Heat and mass balance equations relate the heat input from fuel to the heat output via steam as well as accounting for air and flue gas flows.
- A worked example calculates furnace conditions like flue gas temperature for a methane-fueled boiler, assuming radiation is the only heat transfer mode in the furnace. Tube bank calculations then determine the exit gas
This document summarizes a CFD investigation of the effect of changing the angle of secondary air on NOx emissions in a 660 MW tangentially fired coal boiler. The study found that changing the angle of secondary air from horizontal to an inclined angle reduced NOx levels at the furnace outlet by 15%, from 166 ppm to 143 ppm. A CFD model was developed and validated against plant data to analyze the combustion and flow patterns with different secondary air parameters. The optimized secondary air configuration lowered NOx emissions through improved mixing and delayed ignition.
PyTeCK: A Python-based automatic testing package for chemical kinetic modelsOregon State University
Β
Combustion simulations require detailed chemical kinetic models to predict fuel oxidation, heat release, and pollutant emissions. These models are typically validated using qualitative rather than quantitative comparisons with limited sets of experimental data. This work introduces PyTeCK, an open-source Python-based package for automatic testing of chemical kinetic models. Given a model of interest, PyTeCK automatically parses experimental datasets encoded in a YAML format, validates the self-consistency of each dataset, and performs simulations for each experimental datapoint. It then reports a quantitative metric of the model's performance, based on the discrepancy between experimental and simulated values and weighted by experimental variance. The initial version of PyTeCK supports shock tube and rapid compression machine experiments that measure autoignition delay. PyTeCK relies on several packages in the SciPy stack and greater scientific Python ecosystem. In addition to providing an easy-to-use, automated tool for evaluating chemical kinetic model performance, a secondary objective of PyTeCK is to encourage greater openness and reproducibility in combustion research.
Design With Solid works Software and Planning Calculation Analysis of Fire Tu...IJRES Journal
Β
Steam boilers (boilers) is a closed vessel made of steel that is used to generate steam. In the modern era many industries such as household scale industries for the manufacture of oyster mushroom spawn to use aid as a supplier of steam boilers are used as a sterilization process baglog. Annually, the number of requests oyster mushroom spawn have been increases, so the boiler is very significant equipment to increase the number of baglog production as oyster mushroom growing media.To help to fulfill the small industryrequiremets for oyster mushroom nursery,plannedatype offire tubeboilerthatcanhelpthe availability ofsteam ina lowscalewithsteamoutputcapacity of70kg/ h, temperature120β, pressure1.5barandusingmaterialsLPGfuelas a source ofheatenergy.From the results of this design, fire tube boiler have efficiency of 0.934 % . The kettle body is made from asphalt drums pertamina with the Cold Rolled Steel materials. Used asphalt drums because of its availability in the market more easier to obtained easily and the dimensions of asphalt drum capable of holding for temperature and pressure have been determined . As for the pipe material using Carbon Steel Tubing Boilers ASME SA - 178A GRADE A / SA - 214 (Plain Carbon).
Mech 0036 exam 12 13 with answers (revision)Mostafa Tamish
Β
This document appears to be a past exam paper and marking scheme for a Thermal Power Plant and Heat Transfer course. It contains 6 questions testing various concepts related to thermodynamics, heat transfer, steam power plants, gas turbines, and refrigeration. For each question, it provides the question prompt, relevant figures or tables, and a detailed multi-part solution and marking scheme. The questions cover topics such as spark ignition engines, Rankine cycles, heat exchangers, radiation heat transfer, and gas turbine cycles.
The document analyzes the thermodynamic performance of a lithium bromide (LiBr) and water based vapor absorption air conditioning system that utilizes waste exhaust heat from a diesel engine. The system consists of a generator, condenser, evaporator, absorber, and solution heat exchanger. The effects of varying the temperatures of these components on the system's coefficient of performance (COP) and exergy efficiency are examined. The results show that COP increases with higher evaporator temperature but decreases with higher condenser and absorber temperatures. Exergy analysis indicates the condenser and absorber have higher exergy losses than the generator and evaporator. A small-scale LiBr-water system can feasibly operate using exhaust heat from
Flame stabilisation in microcombustors Shyam Kumar
Β
Microcombustion involves combustion in devices with characteristic lengths smaller than 1 mm. It has applications in micro-thrusters and micro-air vehicles. Key challenges in microcombustion include low Reynolds and Peclet numbers, short residence times, increased heat transfer through conduction and radiation, and flame quenching due to increased surface area to volume ratios. Various microcombustor designs aim to address these issues through techniques like preheating reactants, insulating combustor walls, incorporating heat recirculation or catalytic combustion to improve stability. Stability is also influenced by parameters like flow velocity, wall conductivity, combustor geometry and choice of fuel.
The document discusses energy conservation through waste heat recovery and combined heat and power generation. It provides two case studies as examples. The first case study examines using waste heat from a diesel engine exhaust to generate steam and distilled water. The second case study compares the environmental and economic benefits of a combined heat and power system versus separate heat and power generation. Key topics covered include definitions of waste heat recovery and combined heat and power, types and sources of waste heat, and the environmental and financial benefits of combined heat and power systems.
This document discusses boiler efficiency and the factors that affect it. It provides two methods for calculating efficiency - the indirect or loss method, and the direct method. The indirect method calculates efficiency by determining the percentage losses due to factors like flue gas, hydrogen in fuel, moisture, etc. The direct method calculates efficiency as the ratio of useful steam output to heat input. The document also lists ways to improve boiler efficiency, such as oxygen trim systems, flue gas temperature control, and proper water treatment and blowdown control.
Energy performance assessment of boilersUtsav Jain
Β
The document discusses performance testing of boilers. It describes various factors that affect boiler performance over time such as poor combustion, heat transfer fouling, and deteriorated fuel and water quality. Boiler efficiency testing is important to evaluate how efficiency changes from the design value and identify problems. The direct method and indirect method of testing are described. The indirect method involves calculating different heat losses in the boiler system to determine efficiency. Various measurements, instruments, test conditions and computational procedures for conducting boiler performance tests are outlined.
The fuel-air cycle provides a more accurate model of the actual thermodynamic cycle in an internal combustion engine compared to the air standard cycle by accounting for:
1) The actual composition of gases in the cylinder, which varies throughout the cycle.
2) Variations in specific heat and dissociation effects at high temperatures.
3) Changes in the number of moles as pressure and temperature fluctuate.
The fuel-air cycle shows that efficiency is maximized with a slightly rich mixture near stoichiometric due to higher temperatures from dissociation. It also demonstrates efficiency gains from higher compression but losses from richer mixtures beyond stoichiometric due to incomplete combustion.
This document discusses high efficiency electric power generation technologies. It reviews electric power plant efficiency and how efficiency improvements can reduce all emissions, including carbon dioxide, without additional environmental equipment. Higher efficiency is the most practical way to currently reduce CO2 emissions from fossil fuel plants. Advanced steam, gas turbine, and coal gasification combined cycle plants that can achieve over 50% efficiency are discussed and compared. Supercritical and ultra-supercritical steam plants burning pulverized coal are highlighted as mature, high efficiency options for new plants and upgrades.
The document contains examples of problems related to applied thermodynamics and heat engines. It includes 6 examples that cover topics like determining interface temperatures, heat transfer in heat exchangers, radiation from blackbodies, compression of gases, heating of water, and heat transfer over flat plates. The examples provide calculations and step-by-step workings to arrive at the solutions.
This document discusses heat transfer processes and computational fluid dynamics (CFD) modeling of industrial furnaces. It begins with an introduction to heat transfer by conduction, radiation, and convection. It then provides an overview of CFD and the governing equations used. The remainder of the document discusses preprocessing such as building geometries and applying meshes, discretization methods like finite volume and finite element, and schemes for calculating variable values at cell faces like upwinding and central differencing. The goal is to simulate the temperature profile and optimize energy usage in an industrial furnace using CFD.
This document discusses boiler efficiency, including types of efficiency measurements like combustion efficiency, thermal efficiency, and seasonal efficiency. It explains what makes a boiler condensing and how condensing boilers can achieve higher efficiencies up to 98%. The document also covers relationships between flue temperature, condensing, and efficiency as well as considerations for applying condensing boilers.
IJERD (www.ijerd.com) International Journal of Engineering Research and Devel...IJERD Editor
Β
This document summarizes a study on improving the performance of an air conditioning system by using a matrix heat exchanger. The study found that adding a matrix heat exchanger between the condenser and expansion valve improved the system's coefficient of performance (COP) and reduced power consumption compared to the standard vapor compression cycle without a heat exchanger. Specifically, the system using the matrix heat exchanger saw a 33.84% reduction in energy consumption and higher COP at different cooling loads compared to the standard system. The results indicate that integrating a matrix heat exchanger enhances the efficiency of an air conditioning system.
The document discusses the coefficient of performance (COP) as it relates to heat pumps and refrigeration systems. It provides definitions and equations for calculating COP for both heating and cooling applications. Higher COP values indicate greater efficiency, with optimal performance dependent on factors like temperature differences and system design. Real-world COP is typically lower than theoretical maximums due to irreversible processes and other losses.
Boiler Efficiency Improvement through Analysis of Lossesijsrd.com
Β
Thermal is the main source for power generation in India. The percentage of thermal power generation as compare to other sources is 65 %. The main objective of thermal power plant is to fulfill the energy demands of the market and to achieve these demands; plant requires technical availability with the parts reliability and maintenance strategy. This paper deals with the determination of current operating efficiency of Boiler and calculates major losses for Vindhyachal Super thermal power plant (India) of 210 MW units. Then identify the causes of performance degradation. Also find the major causes of heat losses by Fault Tree Analysis (FTA) and recommends its appropriate strategy to reduce major losses. The aim of performance monitoring is continuous evaluation of degradation i.e. decrease in performance of the steam boiler. These data enable additional information which is helpful in problem identification, improvement of boiler performance and making economic decisions about maintenance schedule.
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.
This document discusses different components of fossil-fuel steam generators. It describes boilers, explaining that they are classified in various ways such as by tube content and fuel type. It also defines boiler horsepower. The document then discusses the purpose and advantages of economizers and air preheaters. It provides examples of calculating boiler and economizer efficiency. Finally, it describes superheaters and condensers, explaining superheater types and the purpose of condensers.
1. The document discusses methods for assessing the energy performance of boilers through efficiency testing.
2. There are two main methods - the direct method compares energy input from fuel to useful energy output in steam. The indirect method calculates boiler efficiency by measuring all heat losses and subtracting from 100%.
3. Key advantages of the indirect method are that it provides clues to potential issues affecting efficiency and errors in measurements do not significantly impact the efficiency calculation.
This document discusses energy efficiency and auditing of industrial utilities. It begins by defining energy efficiency as reducing energy input without negatively affecting output. The objectives of industrial energy efficiency are outlined as minimizing costs and energy waste, optimizing energy use, improving environmental performance, and enhancing reputation. Key industrial utilities discussed include boilers, furnaces, electric motors, pumps, compressors, and HVAC systems. Methods of assessing the efficiency of these systems and opportunities for improved energy efficiency are also presented.
This document discusses various thermodynamic cycles used in power generation applications including vapor power cycles, gas power cycles, and gas turbine cycles. It describes the basic processes and assumptions of cycles like the Rankine, Otto, diesel, and Brayton cycles. Methods to improve the performance of these cycles are also covered, such as increasing boiler pressure, superheating, reheating, and regeneration. The key applications of thermodynamics discussed are steam power plants, internal combustion engines, and gas turbine engines.
The document provides information on assessing the energy performance of boilers through testing. It discusses how boiler efficiency and evaporation ratio can decrease over time due to various factors like poor combustion, fouling, and deteriorating fuel/water quality. The purpose of performance testing is to determine the actual efficiency and compare it to design values in order to identify areas for improvement. Both direct and indirect testing methods are described as well as the necessary measurements, instruments, standards, and considerations involved in conducting the tests. Formulas are also provided for calculating efficiency using the indirect method by establishing heat losses from the boiler.
This document describes the optimization of a packed bed reactor (PBR) and alternative fluidized bed reactor (FBR) designs for the production of styrene. Three methods for steam contacting are evaluated: a heat exchanger, direct injection, and heat exchanger for the FBR modeled as a continuous stirred tank reactor (CSTR). Optimization trials are performed by varying inlet temperature, pressure, and feed rate to maximize profit. Direct injection of steam into the PBR is found to be the most profitable design.
Effect of Combustion Air Pre-Heating In Carbon Monoxide Emission in Diesel Fi...IJERA Editor
Β
This paper describes the effect of combustion air pre- heating in Diesel fired heat Treatment Furnace. The main
heat treatment processes are Normalizing, Tempering, Hardening, Annealing, Solution Annealing and Stress
Relieving. The emission of carbon monoxide is measured with combustion air pre-heating and without preheating.
The results are then compared and it is found that the emission of CO is reduced by 29.12%. With the
Combustion air pre-heating a considerable reduction in Specific Furnace Fuel Consumption (SFFC) is obtained.
The test was caaried out at Peekay Steels Casting (P) ltd, Nallalam, Calicut.
General Terms: Heat Treatment Furnace
Actual cycles for internal combustion engines differ from air-standard cycles in many respects.
Time loss factor.
Heat loss factor.
Exhaust blow down factor.
This document provides 20 methods for improving boiler efficiency. Some key methods include reducing excess air, decreasing flue gas temperature, optimizing boiler operation, stopping steam leaks, reducing deposits in burners and on boiler surfaces, recovering heat from blowdown, and insulating boiler components to reduce heat loss. Implementing multiple efficiency improvements can potentially save up to 30% in fuel costs by lowering heat losses and improving combustion. Proper maintenance and optimization of boiler operations and components are important to maximize efficiency.
Plasticization rates can be greatly increased with the use of grooved feed extrusion. Grooved feed extruders can be used in a wide range of extrusion processes for higher output rates. This technology has doubled plasticization rates for some resins and processes as compared to smooth bore extruders.
This paper will compare the performance of three different screw geometries while processing fractional melt HDPE. One of the main methods of evaluation will be the comparison of internal pressure profiles over the entire length of the screw at eleven different locations down the length of the barrel at two L/D apart.
Domestic electrical systems provide a core source of energy in modern societies. Electricity is generated through converting mechanical energy to electrical energy in generators, then distributed through high-voltage power lines to minimize energy loss. In homes, electricity is delivered through ring main wiring systems at 240 volts and 50 Hertz, with safety features like fuses, circuit breakers, and grounding to prevent electric shocks.
This document discusses boiler efficiency and the factors that affect it. It provides two methods for calculating efficiency - the indirect or loss method, and the direct method. The indirect method calculates efficiency by determining the percentage losses due to factors like flue gas, hydrogen in fuel, moisture, etc. The direct method calculates efficiency as the ratio of useful steam output to heat input. The document also lists ways to improve boiler efficiency, such as oxygen trim systems, flue gas temperature control, and proper water treatment and blowdown control.
Energy performance assessment of boilersUtsav Jain
Β
The document discusses performance testing of boilers. It describes various factors that affect boiler performance over time such as poor combustion, heat transfer fouling, and deteriorated fuel and water quality. Boiler efficiency testing is important to evaluate how efficiency changes from the design value and identify problems. The direct method and indirect method of testing are described. The indirect method involves calculating different heat losses in the boiler system to determine efficiency. Various measurements, instruments, test conditions and computational procedures for conducting boiler performance tests are outlined.
The fuel-air cycle provides a more accurate model of the actual thermodynamic cycle in an internal combustion engine compared to the air standard cycle by accounting for:
1) The actual composition of gases in the cylinder, which varies throughout the cycle.
2) Variations in specific heat and dissociation effects at high temperatures.
3) Changes in the number of moles as pressure and temperature fluctuate.
The fuel-air cycle shows that efficiency is maximized with a slightly rich mixture near stoichiometric due to higher temperatures from dissociation. It also demonstrates efficiency gains from higher compression but losses from richer mixtures beyond stoichiometric due to incomplete combustion.
This document discusses high efficiency electric power generation technologies. It reviews electric power plant efficiency and how efficiency improvements can reduce all emissions, including carbon dioxide, without additional environmental equipment. Higher efficiency is the most practical way to currently reduce CO2 emissions from fossil fuel plants. Advanced steam, gas turbine, and coal gasification combined cycle plants that can achieve over 50% efficiency are discussed and compared. Supercritical and ultra-supercritical steam plants burning pulverized coal are highlighted as mature, high efficiency options for new plants and upgrades.
The document contains examples of problems related to applied thermodynamics and heat engines. It includes 6 examples that cover topics like determining interface temperatures, heat transfer in heat exchangers, radiation from blackbodies, compression of gases, heating of water, and heat transfer over flat plates. The examples provide calculations and step-by-step workings to arrive at the solutions.
This document discusses heat transfer processes and computational fluid dynamics (CFD) modeling of industrial furnaces. It begins with an introduction to heat transfer by conduction, radiation, and convection. It then provides an overview of CFD and the governing equations used. The remainder of the document discusses preprocessing such as building geometries and applying meshes, discretization methods like finite volume and finite element, and schemes for calculating variable values at cell faces like upwinding and central differencing. The goal is to simulate the temperature profile and optimize energy usage in an industrial furnace using CFD.
This document discusses boiler efficiency, including types of efficiency measurements like combustion efficiency, thermal efficiency, and seasonal efficiency. It explains what makes a boiler condensing and how condensing boilers can achieve higher efficiencies up to 98%. The document also covers relationships between flue temperature, condensing, and efficiency as well as considerations for applying condensing boilers.
IJERD (www.ijerd.com) International Journal of Engineering Research and Devel...IJERD Editor
Β
This document summarizes a study on improving the performance of an air conditioning system by using a matrix heat exchanger. The study found that adding a matrix heat exchanger between the condenser and expansion valve improved the system's coefficient of performance (COP) and reduced power consumption compared to the standard vapor compression cycle without a heat exchanger. Specifically, the system using the matrix heat exchanger saw a 33.84% reduction in energy consumption and higher COP at different cooling loads compared to the standard system. The results indicate that integrating a matrix heat exchanger enhances the efficiency of an air conditioning system.
The document discusses the coefficient of performance (COP) as it relates to heat pumps and refrigeration systems. It provides definitions and equations for calculating COP for both heating and cooling applications. Higher COP values indicate greater efficiency, with optimal performance dependent on factors like temperature differences and system design. Real-world COP is typically lower than theoretical maximums due to irreversible processes and other losses.
Boiler Efficiency Improvement through Analysis of Lossesijsrd.com
Β
Thermal is the main source for power generation in India. The percentage of thermal power generation as compare to other sources is 65 %. The main objective of thermal power plant is to fulfill the energy demands of the market and to achieve these demands; plant requires technical availability with the parts reliability and maintenance strategy. This paper deals with the determination of current operating efficiency of Boiler and calculates major losses for Vindhyachal Super thermal power plant (India) of 210 MW units. Then identify the causes of performance degradation. Also find the major causes of heat losses by Fault Tree Analysis (FTA) and recommends its appropriate strategy to reduce major losses. The aim of performance monitoring is continuous evaluation of degradation i.e. decrease in performance of the steam boiler. These data enable additional information which is helpful in problem identification, improvement of boiler performance and making economic decisions about maintenance schedule.
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.
This document discusses different components of fossil-fuel steam generators. It describes boilers, explaining that they are classified in various ways such as by tube content and fuel type. It also defines boiler horsepower. The document then discusses the purpose and advantages of economizers and air preheaters. It provides examples of calculating boiler and economizer efficiency. Finally, it describes superheaters and condensers, explaining superheater types and the purpose of condensers.
1. The document discusses methods for assessing the energy performance of boilers through efficiency testing.
2. There are two main methods - the direct method compares energy input from fuel to useful energy output in steam. The indirect method calculates boiler efficiency by measuring all heat losses and subtracting from 100%.
3. Key advantages of the indirect method are that it provides clues to potential issues affecting efficiency and errors in measurements do not significantly impact the efficiency calculation.
This document discusses energy efficiency and auditing of industrial utilities. It begins by defining energy efficiency as reducing energy input without negatively affecting output. The objectives of industrial energy efficiency are outlined as minimizing costs and energy waste, optimizing energy use, improving environmental performance, and enhancing reputation. Key industrial utilities discussed include boilers, furnaces, electric motors, pumps, compressors, and HVAC systems. Methods of assessing the efficiency of these systems and opportunities for improved energy efficiency are also presented.
This document discusses various thermodynamic cycles used in power generation applications including vapor power cycles, gas power cycles, and gas turbine cycles. It describes the basic processes and assumptions of cycles like the Rankine, Otto, diesel, and Brayton cycles. Methods to improve the performance of these cycles are also covered, such as increasing boiler pressure, superheating, reheating, and regeneration. The key applications of thermodynamics discussed are steam power plants, internal combustion engines, and gas turbine engines.
The document provides information on assessing the energy performance of boilers through testing. It discusses how boiler efficiency and evaporation ratio can decrease over time due to various factors like poor combustion, fouling, and deteriorating fuel/water quality. The purpose of performance testing is to determine the actual efficiency and compare it to design values in order to identify areas for improvement. Both direct and indirect testing methods are described as well as the necessary measurements, instruments, standards, and considerations involved in conducting the tests. Formulas are also provided for calculating efficiency using the indirect method by establishing heat losses from the boiler.
This document describes the optimization of a packed bed reactor (PBR) and alternative fluidized bed reactor (FBR) designs for the production of styrene. Three methods for steam contacting are evaluated: a heat exchanger, direct injection, and heat exchanger for the FBR modeled as a continuous stirred tank reactor (CSTR). Optimization trials are performed by varying inlet temperature, pressure, and feed rate to maximize profit. Direct injection of steam into the PBR is found to be the most profitable design.
Effect of Combustion Air Pre-Heating In Carbon Monoxide Emission in Diesel Fi...IJERA Editor
Β
This paper describes the effect of combustion air pre- heating in Diesel fired heat Treatment Furnace. The main
heat treatment processes are Normalizing, Tempering, Hardening, Annealing, Solution Annealing and Stress
Relieving. The emission of carbon monoxide is measured with combustion air pre-heating and without preheating.
The results are then compared and it is found that the emission of CO is reduced by 29.12%. With the
Combustion air pre-heating a considerable reduction in Specific Furnace Fuel Consumption (SFFC) is obtained.
The test was caaried out at Peekay Steels Casting (P) ltd, Nallalam, Calicut.
General Terms: Heat Treatment Furnace
Actual cycles for internal combustion engines differ from air-standard cycles in many respects.
Time loss factor.
Heat loss factor.
Exhaust blow down factor.
This document provides 20 methods for improving boiler efficiency. Some key methods include reducing excess air, decreasing flue gas temperature, optimizing boiler operation, stopping steam leaks, reducing deposits in burners and on boiler surfaces, recovering heat from blowdown, and insulating boiler components to reduce heat loss. Implementing multiple efficiency improvements can potentially save up to 30% in fuel costs by lowering heat losses and improving combustion. Proper maintenance and optimization of boiler operations and components are important to maximize efficiency.
Plasticization rates can be greatly increased with the use of grooved feed extrusion. Grooved feed extruders can be used in a wide range of extrusion processes for higher output rates. This technology has doubled plasticization rates for some resins and processes as compared to smooth bore extruders.
This paper will compare the performance of three different screw geometries while processing fractional melt HDPE. One of the main methods of evaluation will be the comparison of internal pressure profiles over the entire length of the screw at eleven different locations down the length of the barrel at two L/D apart.
Domestic electrical systems provide a core source of energy in modern societies. Electricity is generated through converting mechanical energy to electrical energy in generators, then distributed through high-voltage power lines to minimize energy loss. In homes, electricity is delivered through ring main wiring systems at 240 volts and 50 Hertz, with safety features like fuses, circuit breakers, and grounding to prevent electric shocks.
1) The document describes a case study of the GTower building in Kuala Lumpur, Malaysia. GTower implemented various passive design strategies to achieve Green Mark Gold certification from the Singapore Building and Construction Authority.
2) Key passive design elements included building orientation to the northeast to minimize solar heat gain, vertical gardens on the facade, and double glazed glass with low-emissivity coatings. These strategies helped reduce energy consumption and maintain a comfortable indoor temperature.
3) The case study analyzed climate data, sun path analysis, and wind patterns to inform the passive design strategies employed in the building's design.
This document summarizes research on adaptive facades. It discusses various facade functions including thermal, acoustic, and visual comfort. It describes different types of facade systems that provide ventilation, heating, cooling, and sun protection. These include double skin facades, box window facades, corridor facades, and chimney box windows. The document also discusses integrating mechanical systems into facades and developing facades as active, adaptable skins or organs of the building.
Hot Climate Double Facades: A Focus on Solar AvoidanceTerri Meyer Boake
Β
An overview of the adaptation of double facade systems for iconic buildings in the Gulf Region through the adaptation of the traditional mashrabiya screen.
This document provides an overview of mechanical ventilation, including:
1) How mechanical ventilation helps reduce the work of breathing and restore gas exchange through invasive and noninvasive positive pressure ventilation.
2) The basics of monitoring pressure, volume, flow, and pressure-time curves at the bedside.
3) Important considerations for mechanical ventilation including potential adverse effects on hemodynamics, lungs, and gas exchange, and how to address issues like auto-PEEP.
This document proposes a hybrid PID-cascade control system for HVAC systems to improve control performance. It models the heat exchanger and air conditioning space components of an HVAC system. It then designs a hybrid PID-cascade controller that combines traditional PID control with an internal cascade loop. Simulations show the hybrid controller has faster response, better setpoint tracking and disturbance rejection compared to traditional PID, compensator and Ziegler-Nichols tuned PID controllers. The cascade control inner loop improves response speed and precision, while the outer PID loop enhances stability and disturbance rejection for the HVAC system.
Development and theoretical analysis of mathematical expressions for change o...ijsrd.com
Β
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Comsol Simulation Paper
1. 1
Group 4
Jun Dong (260442997)
Erbolat Riskulov (260483028)
Dillon Stanger (260411556)
BREE 501 β Simulation & Modeling
Assignment 2d
Dr. Grant Clark
April 14th
, 2014
Simulation of a Rocket Mass Heater Stove
Conceptual Model
Context
The Rocket Mass Heater Stove (RMHS) is a super-efficient hybrid masonry wood stove which,
anecdotally, uses between 75-90% less wood than conventional wood stoves, and emits no smoke
for the majority of the burn cycle. In summary, fire burns sideways and up a heat riser producing
turbulence and a clean burn. Then the exhaust snakes
through a system of piping within a thermal mass to store
excess heat and exits out building. To get the RMHS
authorized for permitted projects, the RMHS needs to be
tested by registered lab. Our team will simulate several heat
transfer characteristics of the RMHS to assure it will pass
the lab testing.
Figure 1. A 3d X-ray view of a fire-brick Rocket Mass
Heater Stove excluding the thermal bench exhaust piping.
From right to left, the wood feed to the firebox to the heat
riser on the left. The combustion chamber is included in the
cylindrical oil drum. Below is the pad which supports and
insulates the RMHS. Produced using AutoCADTM
.
Objective
The simulation will analyze for the correlation between high temperature and turbulence for clean
burning inside the RMHS system. The simulation will focus on locating the temperature
distribution and the airflow pattern. Our team anticipates that to successfully simulate the RMHS:
(1) the initial simulation must be simple (simulate the burning of wood within a cylinder) and (2)
our team must understand the heat transfer of combustion, fluid flow dynamics and how to
implement those physical models in COMSOL MultiphysicsTM
. This problem can be approached
as a direct analysis problem where the responses of the fluid flow and temperature profile are
simulated and analyzed (Karplus, 1983).
2. 2
Description
Refer to Figure 2 to the system and its component interactions. Wood fuel, the excitation, is
dropped into the wood feed and burns sideways (response) into and through the firebox. Smoke
produced from combustion, travels to the top of the heat riser, hits the bottom face of the
combustion chamber, and produces turbulent flow (response) within the combustion chamber.
Completely combusted exhaust drops from the combustion chamber to a manifold and exits the
exhaust as steam and carbon dioxide. Though not included in our teamβs simulation, clean exhaust
travels through a system of piping (depositing excess exhaust heat to the masonry thermal mass)
and exits the building through an exit chimney.
Figure 2. RMHS profile with system components, interactions, excitations and responses.
To reduce the system to its simplest form, the system boundary will initially include just the region
within the combustion chamber (the cylindrical oil drum). As our team includes additional
components to the simulation, the system boundary will expand to include the region from the
wood feed to the combustion chamber exhaust. Depending on the effects of the stove material
(fire-brick and steel) our team might choose to or not to include the materials in the system
boundary. The system boundary conditions and the anticipated result are shown from Figure 3.
3. 3
Figure 3: RMH cross-section elevation with specified boundary conditions: temperature (specified
by point and by region), airflows, and aperture area. These temperature values were measured from
a physical prototype for validating the accuracy of the model later on. Specifically, these values
were chosen, as they were the only values empirically measured. Some of these temperature values
can be entered as boundary conditions in COMSOL.
Mathematical Model
Variables
The excitations of the system are the inlet airflow of 1.42 m s-1
at 300K and the heat flux from
wood combustion of 15 kW m-2
(Tran et al. 1992). The temperature for the bottom and the top heat
riser was respectively specified to be 1366K and 1255K. Moreover, the system parameters are
listed in the Table 1 below:
Table 1. System parameters
Parameters Definition
π
π
π
A
Β΅ πππ@ππππ²
π πππ@ππΒ° πͺ
barrel radius , 0.263545m
barrel height, 0.880m
barrel thickness, 0.001524m (16 gauge)
wood feed aperture area, 161cm2
1.983 β 10β5
kg mβ1
s (Engineering Toolbox, 2014a)
1.184kg mβ3 (Engineering Toolbox, 2014b)
4. 4
The following Table 2 lists the variables for mathematical models described in the next
Mathematical Principles section.
Table 2: Equation variables
Variable Definition
πͺ π
π
π°
π
π
π
π»
π
π΅
π΅π
(π΅π) π»
π
Q
heat capacity (J Kβ1)
body force (N) (R. Hesketh, 2008)
velocity gradient tensor matrix
thermal conductivity (W mβ1
Kβ1)
pressure (N mβ2)
density (kg mβ3)
temperature (K)
velocity field matrix (m s-1
)
gradient or "grad" of a scalar field (R. Hesketh, 2008)
velocity gradient (sβ1) expressed as: π’
βu
βx
+ π£
βu
βy
+ π€
βu
βz
, (R. Hesketh, 2008)
transpose of the gradient of the velocity matrix
acceleration due to the force of gravity (9.81 m sβ2)
heating power per unit volume (W mβ3
).
Mathematical Principles
Laminar Fluid Flow
As turbulence flow module was unavailable on the academic version of COMSOL, our team chose
the easier laminar flow module on COMSOL computing with the following set of Equation 1
(COMSOL, 2013). This is the Navier-Stokes equation governing the motion of a non-turbulent
Newtonian fluid, such as our working fluid, air. Fluid flow is important in understanding how the
hot air traverses our system and how the temperature is distributed.
π(π β π»)π (1a)
π» β [βππ° + π(π»π + (π»π) π) β
2
3
π(π» β π)π°] + π (1b)
π» β (ππ) = 0 (1c)
Heat Transfer in Fluids
The physics module of heat transfer in fluids (Equation 2) in COMSOL (COMSOL, 2013)
described the relationship between the fluid flow and heat transfer because the majority of heat
transfer produced from the RMHS after combustion manifests in forced convection, a mode of
heat transfer integral with fluid flow. In the equation below, T2 is the initial temperature of the working
fluid (300K). During the simulation, we included additional boundary conditions from Figure 3.
ππΆ π π β π»π2 = π» β (ππ»π2) + π + π π€β + ππ (2)
5. 5
Computational Model
Methodology
The physics, laminar fluid flow was chosen over turbulent because the turbulence module was not
available on the student version of COMSOL. Furthermore, the laminar flow allows simplifying
the simulation. Next, the heat transfer through fluids physics was added to simulate the
temperature profile. The implementation of the conceptual model followed several basic steps
illustrated in Table 3.
Table 3. Computational model building
Procedure Specification
Global variables Airflow velocity at the inlet and outlet
Temperature at the base and top of the heat riser
Create model geometry Oil drum shell Heat riser Air space
Assign material Steel AISI 4340 Fire brick Air
Physics Solid conductive heat transfer Fluid flow and
convective heat transfer
Mesh Coarse mesh
Computation Time dependent study for airflow velocity
Post-processing Check internal correctness and check applicability of model by
comparing it to empirical data from a prototype.
From Table 5, only the extra-coarse meshing was applied because the computer does not have
enough resource to perform the simulation within an hour. Finally, the meshed computational
model built in COMSOL is shown in Figure 4 below:
Figure 4. Top view (left) and bottom view (right) of the computational model built in COMSOL
6. 6
Preliminary Result
As shown in Figure 5, the air entering the heat riser at a speed of 0.7 m s-1
. The air cools down
through the heat riser and the barrel with a outside boundary temperature of 300K. As a result, the
airflow speed is decreased to a flow speed of about 0.2 m s-1
while the air is travelling through the
system. However, when air reaches the outlet, its flow speed increases to about 1.4 m s-1
.
Moreover, Figure 5 shows that the temperature is hotter (1300K) on the top part of the heat riser
and colder elsewhere (300K). In sum, the preliminary results do not seem to be reasonable and it
is not comparable to the anticipated values, as shown in Figure 3, measured from a prototype.
More details about the model are shown in the Appendix A.
Figure 5. The airflow velocity (left) is shown higher when air approaching the heat riser, but
slower as the air cools through the upper part of the barrel. The temperature distribution (right)
shows a hotter and lower part of the heat riser.
Problem & Challenge
The first simulation took no less than one hundred (100) minutes. Elimination of certain parameters
in future simulations reduced the solution time considerably. The simulation result showed the
flow velocity distribution in slices rather than a uniform distribution, but was corrected by using a
different viewing scheme in future models. The time dependent solver (set to calculate the
temperature and velocity one (1) second at ten (10) times steps) was unsuitable to address our
objectives to learn about the RMHS at steady state. Furthermore, the flow velocity and the
temperature distributions seem uncorrelated to the prototype values. For instance, the minimum
temperature within the system was actually the outside ambiance temperature of 300K. This means
that the upper part of the stove is not heated at all. Moreover, the simulation took more than one
hour to compute. Hence, these issues was resolved after some improvements that are discussed in
the upcoming Validation section.
7. 7
Validation
Simplifications and Improvements
The model was simplified that reduced the computation time. Firstly, the top cover attached to the
drum, which had a diameter slightly larger than the outer shell, is now reduced to fit the shell wall.
This lowered the number of unnecessary computation on the extra number of finite elements.
Furthermore, the stationary study provided more realistic results compared to the original time
dependency study. Velocity profile varied along the combustion chamber, indicating a possible
correlation to the prototype. Temperature profile change is gradual along heat riser, indicating a better
correlation to the prototype. Furthermore, the final steady state (stationary) simulation time was
reduced drastically down to five (5) seconds.
Conclusions
The final results from Figure 6 are different and more accurate compared to the preliminary results.
The flow velocity is relatively higher on the bottom (0.45-0.76 m s-1
) and the middle part (1.05 m
s-1
) of the system. High airflows, especially in the middle part, mostly occur in where the space is
large and the frictional effect is less. Furthermore, the temperature of about 1260K at the top and
about 1360K at the bottom of the heat riser seemed more reasonable. Thus, compared the airflow
to the simulated temperature distribution on the heat riser, high airflows occur in where the
temperature is hot. Therefore, the question from the objective is answered: there seemed to be a
correlation between high temperature and turbulence (high flow velocity) for a clean burning
inside the RMHS system. However, the turbulence flow module is unavailable for building this
model and the temperature distribution is not completely matching the measured temperature
values from the prototype system (Figure 3). Consequently, the accuracy of the result and the
answer remain invalid. For more information on the computational model, please consult the
Appendix B.
Figure 6. The isosurface plot of airflow velocity (left) shows higher velocities in the bottom and
8. 8
the middle parts of the system. The temperature distribution (right) shows higher temperature on
bottom of the heat riser.
Recommendations
For improvements, the physics of the conductive heat transfer in the barrel shell and the convective
heat transfer to the environment can be implemented so that the model will produce a more realistic
temperature profile of the entire system resembling to the prototype. Other parts of the RMHS,
such as the firebox and the exhaust outlet, can be introduced in continuing this project. Each part
of the RMHS will be simulated and the results can then be imputed on the boundary of the parts
adjoining it. In that way, the velocity and temperature profiles of the entire system can be simulated
without requiring much computational resources. Thus, the meshing size can be reduced to
improve the resolution of the results. Combustion of the wood could be simulated using an
additional module from COMSOL. By adding the extra turbulence flow module from COMSOL,
the model will be able to simulate the turbulence flow as stated in the objective. Moreover, the
RMHS system designed in AutoCAD with precise surface irregularities could be used as the
geometry if COMSOL was able to import it properly. Combining the CAD geometry with
turbulence flow and the time dependent particle collision and tracing physics, the airflow can be
simulated with higher degree of realism.
References
COMSOL. 2013. COMSOL: Multiphysics. Ver. 4.4. Burlington, MA.: COMSOL Inc.
COMSOL. 2013. Introduction to Multiphysics. Burlington, MA.: COMSOL Inc.
Engineering Toolbox. 2014a. Air - Absolute and Kinematic Viscosity. The Engineering Toolbox. The Engineering
Toolbox. Available at: http://www.engineeringtoolbox.com/air-absolute-kinematic-viscosity-d_601.html.
Accessed 17 March 2014.
Engineering Toolbox. 2014b. Air β Density and Specific Weight. The Engineering Toolbox. The Engineering
Toolbox. Available at: http://www.engineeringtoolbox.com/air-density-specific-weight-d_600.html. Accessed 17
March 2014.
Hesketh, R. 2008. Flow Between Parallel Plates β Modified from the COMSOL ChE Library module. Rowan
University Information Resources. Glassboro, NJ: Rowan University. Available at:
http://users.rowan.edu/~hesketh/0906-309/Lectures/Flow%20Between%20Parallel%20Plates%20-
%20Comsol2008.pdf. Accessed 27 March 2014.
Karplus, W. J. 1983. The Spectrum of Mathematical Models. L. A.: University of California.
Tran, H. C., R. H. White. 1992. Burning Rate of Solid Wood Measured in a Heat Release Rate Calorimeter. Fire
and Materials. 16(4): 197-206.
9. 9
Appendix
Section A β Preliminary Model Meshing Specifications
Table 4. Preliminary Model Meshing Specifications
Element Size Parameters Values
Maximum Element Size 0.605m
Minimum Element Size 0.0847m
Maximum Element Growth Rate 2
Resolution of Curvature 1
Resolution of Narrow Regions 0.1
Section B β Final Model Meshing Specifications
Table 5. Final Model Meshing Specifications
Parameters Values
Minimum element quality 1.167E-4
Average element quality 0.235
Tetrahedral elements 1342
Triangular elements 608
Edge elements 168
Vertex elements 36
Maximum element size 0.605
Minimum element size 0.0847
Resolution of narrow regions 0.1
Maximum element growth rate 2
Predefined size Extremely coarse