1) The document summarizes an intern's work synthesizing thermoelectric materials and making thermoelectric panels at King Mongkut Institute of Technology Ladkrabang in Bangkok, Thailand.
2) The intern synthesized thermoelectric powders from solid state reactions and made pellets using hydraulic pressing, then fabricated thermoelectric panels of different sizes.
3) Testing of the panels showed limited results due to equipment limitations, but the intern gained skills and experience in thermoelectric material synthesis and device fabrication.
The document describes an experimental device that produces energy through cold fusion reactions without external energy input. The device consists of diodes made of palladium powder and semiconductor powder junctions. Fusion reactions in the junctions excite the semiconductor electrons, allowing them to produce a spontaneous voltage over 0.5 volts without external stimulation. This voltage suggests very high electric fields at the nano-scale junction increase fusion probability. Initial testing of the diodes produced low microwatt power levels but directly as electricity rather than heat. Further experiments aim to correlate electric outputs to calorimetry measurements to confirm power exceeds inputs.
The document discusses thermal properties of matter, specifically heat capacity and specific heat capacity. It defines heat capacity as the amount of energy needed to change an object's temperature by 1 degree. Specific heat capacity is the amount of energy needed to change 1 kg of a material by 1 degree. Materials have different specific heat capacities because their molecules contain different numbers and masses of atoms. The document also describes methods to determine specific heat capacity, including direct calorimetry of liquids and solids, and the indirect method of mixtures.
This Application Note illustrates the use and advantages of dielectric heating, which as the name implies, is used for materials that are non-conducting. The essential advantage of dielectric heating is that the heat is generated within the material to be heated. In comparison with more conventional heating techniques (hot air, infrared, et cetera) in which the material is heated via the outer surface, dielectric heating is much more rapid. This is because electrical insulating materials, i.e. the domain of dielectric heating, are usually also poor conductors of heat.
Other interesting characteristics of radio frequency and microwave heating are the high power density and the potential for selectively heating materials. However, dielectric heating is a very expensive technique that cannot usually compete in cost terms with techniques such as resistance or infrared heating.
This document discusses thermal properties of matter including heat capacity, specific heat capacity, and changes of state. It defines heat capacity as the amount of energy required to change an object's temperature by a given amount. Specific heat capacity is the amount of energy required to raise the temperature of 1 kg of a material by 1°C. Methods for determining specific heat capacity include direct calorimetry of liquids and solids or the indirect method of mixtures. Phase changes occur when substances gain enough energy to overcome intermolecular forces, changing between solid, liquid, and gas states. Latent heat is the energy required for phase changes without a change in temperature.
The document discusses the particle model of matter and how it relates to the different phases of matter and phase changes. It explains that in solids, particles vibrate around fixed positions, in liquids they can move slowly, and in gases they can move quickly. A phase change occurs when the kinetic energy of particles changes enough for them to overcome attractive forces. Evaporation involves single particles escaping while boiling happens when vapor pressure exceeds atmospheric pressure. Thermal capacity and specific heat capacity are introduced to quantify how much energy is required to change an object's temperature. Latent heat also quantifies energy absorbed or released during phase changes.
1) The document discusses the thermal properties of matter and explains concepts like internal energy, temperature, phase changes, boiling and evaporation.
2) It describes how internal energy is related to the motion of molecules and how temperature increases as internal energy increases during heating.
3) The document explains that during phase changes like boiling and melting, temperature remains constant as energy is used to overcome molecular forces rather than increase motion.
This document summarizes a lab experiment to calculate the heat capacity of solids. It describes measuring the heat capacity of a calorimeter vessel filled with water, then adding solids like graphite and copper pre-heated to 200°C to calculate their specific heat capacities. The experimental procedure, data analysis and calculations are shown. The specific heat capacities calculated for graphite, copper and porcelain are compared to known values, with relative errors of 8.9%, 14.2% and 26% respectively, showing reliable results except for graphite. Sources of error like heat loss during measurements are also discussed.
The document describes an experimental device that produces energy through cold fusion reactions without external energy input. The device consists of diodes made of palladium powder and semiconductor powder junctions. Fusion reactions in the junctions excite the semiconductor electrons, allowing them to produce a spontaneous voltage over 0.5 volts without external stimulation. This voltage suggests very high electric fields at the nano-scale junction increase fusion probability. Initial testing of the diodes produced low microwatt power levels but directly as electricity rather than heat. Further experiments aim to correlate electric outputs to calorimetry measurements to confirm power exceeds inputs.
The document discusses thermal properties of matter, specifically heat capacity and specific heat capacity. It defines heat capacity as the amount of energy needed to change an object's temperature by 1 degree. Specific heat capacity is the amount of energy needed to change 1 kg of a material by 1 degree. Materials have different specific heat capacities because their molecules contain different numbers and masses of atoms. The document also describes methods to determine specific heat capacity, including direct calorimetry of liquids and solids, and the indirect method of mixtures.
This Application Note illustrates the use and advantages of dielectric heating, which as the name implies, is used for materials that are non-conducting. The essential advantage of dielectric heating is that the heat is generated within the material to be heated. In comparison with more conventional heating techniques (hot air, infrared, et cetera) in which the material is heated via the outer surface, dielectric heating is much more rapid. This is because electrical insulating materials, i.e. the domain of dielectric heating, are usually also poor conductors of heat.
Other interesting characteristics of radio frequency and microwave heating are the high power density and the potential for selectively heating materials. However, dielectric heating is a very expensive technique that cannot usually compete in cost terms with techniques such as resistance or infrared heating.
This document discusses thermal properties of matter including heat capacity, specific heat capacity, and changes of state. It defines heat capacity as the amount of energy required to change an object's temperature by a given amount. Specific heat capacity is the amount of energy required to raise the temperature of 1 kg of a material by 1°C. Methods for determining specific heat capacity include direct calorimetry of liquids and solids or the indirect method of mixtures. Phase changes occur when substances gain enough energy to overcome intermolecular forces, changing between solid, liquid, and gas states. Latent heat is the energy required for phase changes without a change in temperature.
The document discusses the particle model of matter and how it relates to the different phases of matter and phase changes. It explains that in solids, particles vibrate around fixed positions, in liquids they can move slowly, and in gases they can move quickly. A phase change occurs when the kinetic energy of particles changes enough for them to overcome attractive forces. Evaporation involves single particles escaping while boiling happens when vapor pressure exceeds atmospheric pressure. Thermal capacity and specific heat capacity are introduced to quantify how much energy is required to change an object's temperature. Latent heat also quantifies energy absorbed or released during phase changes.
1) The document discusses the thermal properties of matter and explains concepts like internal energy, temperature, phase changes, boiling and evaporation.
2) It describes how internal energy is related to the motion of molecules and how temperature increases as internal energy increases during heating.
3) The document explains that during phase changes like boiling and melting, temperature remains constant as energy is used to overcome molecular forces rather than increase motion.
This document summarizes a lab experiment to calculate the heat capacity of solids. It describes measuring the heat capacity of a calorimeter vessel filled with water, then adding solids like graphite and copper pre-heated to 200°C to calculate their specific heat capacities. The experimental procedure, data analysis and calculations are shown. The specific heat capacities calculated for graphite, copper and porcelain are compared to known values, with relative errors of 8.9%, 14.2% and 26% respectively, showing reliable results except for graphite. Sources of error like heat loss during measurements are also discussed.
This document discusses various concepts related to heat, including:
[1] Heat capacity and specific heat capacity, which refer to the amount of heat required to change the temperature of a substance. Specific heat capacity is a material's heat capacity per unit mass.
[2] Latent heat of fusion and vaporization, which is the heat absorbed or released during phase changes between solid, liquid, and gas with no change in temperature.
[3] Methods for determining specific heat capacity experimentally, including the mixture method of transferring heat between substances and the electrical method of applying heat from an electrical source.
Bruce Decker Journal of Thermal EngineeringBruce Decker
This document summarizes the results of experiments testing the thermoelectric properties of bismuth telluride filled silicone composite wires created via electrospinning. Bismuth telluride and silicone rubber were mixed and extruded into millimeter-sized wires. The electrical resistance of the composite wires was measured to be as high as 2.9*1010 ohms. Seebeck coefficient measurements also showed the composite material exhibited a high Seebeck effect due to the low thermal conductivity of the silicone rubber matrix. The flexibility of the composite material and enhancement of bismuth telluride's thermoelectric properties indicates potential for flexible alternative energy applications.
Specific heat capacity and heat capacity are different but related concepts. Specific heat capacity is the amount of heat required to raise the temperature of 1kg of a substance by 1K, while heat capacity does not consider mass and is the amount of heat required to raise the temperature of a substance by 1K. Specific heat capacity includes mass in its calculation and has a consistent, fixed value for a particular substance, while heat capacity can vary for a substance and have the same value for different substances.
An introductory outline of the Physics of Heat. I created this presentation at Curtin Sarawak Malaysia as a basis for Foundation Physics students and others to edit and expand. A Creative Commons Attribution-Share Alike License.
This document provides an introduction to heat transfer. It discusses the key concepts of heat, temperature, thermodynamics and heat transfer. The three main modes of heat transfer are conduction, convection and radiation. Conduction involves the transfer of heat between objects in direct contact. Convection refers to the transfer of heat by the movement of fluids like gases and liquids. Radiation can occur across empty space by electromagnetic waves and does not require a medium. Examples are provided to illustrate each type of heat transfer.
This document discusses different thermal processes involving changes of state:
- Boiling occurs when a liquid absorbs thermal energy and changes to a gas at a constant temperature, breaking molecular bonds. Condensation is the reverse process where a gas releases thermal energy forming liquid bonds.
- Melting absorbs thermal energy at a constant temperature to break solid bonds into liquid. Solidification releases energy forming new solid bonds.
- Evaporation differs from boiling in occurring at any temperature as more energetic molecules overcome surface forces, cooling the remaining liquid. Factors like temperature, pressure and airflow affect evaporation rates.
The set of energy Problems to practice understanding use of q=mCT equation.
Variables and [units]: q - Heat [J]; m - Mass [g]; C - Specific Heat Capacity [J/g*oC or J/g*K]; delta T - change in temperature [oC or K]
This document discusses heat and energy transfer through various physical and chemical processes. It defines key concepts like heat, temperature, endothermic and exothermic reactions, and provides equations and constants for calculating heat transfer and changes in temperature. Practice problems are provided to calculate heat required or lost through changing temperatures of different substances.
This document provides an overview of heat transfer and related topics including:
- The three main modes of heat transfer are conduction, convection, and radiation. Conduction involves the transfer of energy between adjacent particles. Convection involves the movement of heated fluids. Radiation involves the emission and absorption of electromagnetic waves.
- Specific heat capacity refers to the amount of energy required to change the temperature of a material by a certain amount. It varies between materials.
- Thermal conductivity and contact resistance impact heat transfer rates during conduction.
- HVAC systems involve heating, cooling, humidifying, dehumidifying, cleaning, ventilating, and circulating air to control indoor environments.
- Air conditioning expanded the
14 thermal physics thermal properties of matterpranali mankar
This document discusses temperature, heat, and the different methods of heat transfer (conduction, convection, and radiation). It defines temperature as a measure of kinetic energy, and heat as energy transferred between objects at different temperatures. It explains the Celsius, Fahrenheit and Kelvin temperature scales. It then describes conduction as heat transfer through direct contact, convection as heat transfer through fluid movement, and radiation as heat transfer through electromagnetic waves without a medium. It provides examples of each type of heat transfer.
Efficient production of negative hydrogen ions in RF plasma by using a self-b...IJERA Editor
Volume production of negative hydrogen ions is established efficiently in a pure hydrogen RF discharge plasma by using a self-biased grid electrode for production of low electron-temperature and high density plasma. Using this electrode both high and low electron temperature plasmas are produced in the regions separated by the grid electrode in the chamber, in which the electron temperature in the downstream region is controlled by the mesh size and plasma production parameters. The production rate of negative ions depends strongly on the electron temperature varied by the RF input power and hydrogen pressure. In the case of the grid electrode with the 5 mesh/in., the negative hydrogen ions are produced effectively in the downstream region in the hydrogen pressure range of 0.9 −2.7 Pa. In addition, the production rate of the negative ion 퐻 − raises from 62 % to 87 % at 0.9 Pa by changing the RF power from 20 W to 80W.
This document discusses thermal properties of materials. It begins by introducing the group members and outlines for the document. It then defines key concepts like heat capacity, thermal expansion, and thermal conductivity. It explains that metals generally have high heat capacity and thermal conductivity but low thermal expansion. Ceramics have high heat capacity and melting points but low thermal expansion and thermal conductivity. Polymers typically have low densities, heat capacity, thermal expansion, and thermal conductivity. They also have low melting points.
This document provides an overview of heat transfer applications in the oil and gas industry. It discusses key heat transfer methods like conduction, convection and radiation. It also examines how these principles are applied in important industrial equipment like boilers, condensing boilers, piping insulation and heat exchangers. The document aims to explain the importance of heat transfer in petrochemical processes and how different methods are used in applications like heating, cooling, vaporizing and condensing fluid streams.
Thermal expansion, temperature change, and phase change are the three main effects of heat. Thermal expansion causes materials to expand when heated and contract when cooled. The amount of expansion depends on the original length, temperature change, and material's coefficient of linear or volumetric expansion. Temperature change occurs when heat is added or removed from an object, increasing or decreasing its temperature. This temperature change depends on the specific heat capacity of the material, its mass, and the amount of heat added or removed. Phase change involves heat being absorbed or released during changes between solid, liquid, and gas states without a change in temperature. This heat of fusion or vaporization allows materials to change phases.
1. The document discusses measurement of DC resistivity, including specifications for specimen shape and electrode arrangement, materials used for electrodes, and different measuring cell configurations.
2. It also covers partial discharge measurement, defining terms like partial discharge and describing the partial discharge phenomenon in insulation with voids.
3. Breakdown mechanisms in gases, liquids and solids are outlined, focusing on ionization processes in gases which can lead to electrical breakdown at high voltages.
This document discusses different changes of state that matter undergoes. It explains that boiling and condensation involve a transfer of thermal energy without a change in temperature, where boiling transforms liquid to gas and condensation transforms gas to liquid. Melting and solidification also involve thermal energy transfer without temperature change, transforming between solid and liquid. Evaporation differs in that it can occur at any temperature and involves molecules at the surface of a liquid escaping into the air, lowering the liquid's temperature. Factors like temperature, pressure and surface area affect evaporation rates.
When two objects at different temperatures are placed in contact, heat flows from the hotter object to the colder object until they reach the same temperature and are in thermal equilibrium. Thermal equilibrium occurs when the net heat flow between the objects is zero, meaning they are the same temperature. A liquid-in-glass thermometer works by having mercury in a bulb expand up a capillary tube when heated; the distance it travels corresponds to temperature scales defined by fixed points like ice and steam. Mercury is suitable for thermometers because it conducts heat well and expands uniformly with temperature.
1) Evaporation occurs when molecules near the surface of a liquid gain enough kinetic energy to escape, reaching an equilibrium when an equal number return. The boiling point of a liquid is reached when its vapor pressure equals atmospheric pressure.
2) The boiling point of water is 100°C at sea level but varies with altitude and pressure. Raising or lowering pressure by 28 mmHg changes the boiling point 1°C.
3) Thermal expansion causes the volumes of materials to increase with temperature. The degree of expansion varies between materials like brass and steel.
This document contains notes from a Thermal Physics class on various topics:
- Heat flows from hot to cold bodies until thermal equilibrium is reached.
- The Kelvin temperature scale defines absolute zero as 0 K and relates Celsius and Kelvin scales.
- Kinetic theory explains gas properties in terms of molecular motion, assuming molecules are small, hard spheres that collide elastically.
- Internal energy, temperature, heat capacity, phase changes, gas pressure, and the mole concept are defined and related to molecular behavior and properties.
Equations, examples, and questions are provided to illustrate these concepts.
The document discusses heat and thermal equilibrium. It defines key terms like temperature, heat, and thermal contact. It explains that when two objects at different temperatures come into contact, heat is transferred from the hotter object to the cooler one until they reach the same temperature and thermal equilibrium. Examples are given like a wet towel being used to reduce a fever by transferring heat from the body. The document also discusses specific heat capacity and how it relates to how fast an object's temperature changes when heat is gained or lost. Specific heat capacities of different materials are provided.
This document presents a thermoelectric refrigeration system project. It discusses the milestones, realization of the idea, introduction, history and effect of thermoelectric cooling using Peltier modules. It describes the materials, working, dimensions, advantages, drawbacks, applications, cost analysis and conclusion of the project. The project aims to develop a portable thermoelectric refrigerator for preserving insulin in extreme conditions using solar power. It achieves cooling through a single-stage 12V Peltier module and can retain cooling for up to 57 minutes during power outages.
This document presents a thermoelectric refrigeration system project. It discusses the milestones, realization of the idea, introduction to thermoelectric refrigeration and the Peltier effect. It describes the materials used, working of the project including dimensions, advantages, drawbacks, applications, cost analysis, new opportunities, and concludes that the objective of long term cooling in power failures was achieved with a retention time of 57 minutes.
This document discusses various concepts related to heat, including:
[1] Heat capacity and specific heat capacity, which refer to the amount of heat required to change the temperature of a substance. Specific heat capacity is a material's heat capacity per unit mass.
[2] Latent heat of fusion and vaporization, which is the heat absorbed or released during phase changes between solid, liquid, and gas with no change in temperature.
[3] Methods for determining specific heat capacity experimentally, including the mixture method of transferring heat between substances and the electrical method of applying heat from an electrical source.
Bruce Decker Journal of Thermal EngineeringBruce Decker
This document summarizes the results of experiments testing the thermoelectric properties of bismuth telluride filled silicone composite wires created via electrospinning. Bismuth telluride and silicone rubber were mixed and extruded into millimeter-sized wires. The electrical resistance of the composite wires was measured to be as high as 2.9*1010 ohms. Seebeck coefficient measurements also showed the composite material exhibited a high Seebeck effect due to the low thermal conductivity of the silicone rubber matrix. The flexibility of the composite material and enhancement of bismuth telluride's thermoelectric properties indicates potential for flexible alternative energy applications.
Specific heat capacity and heat capacity are different but related concepts. Specific heat capacity is the amount of heat required to raise the temperature of 1kg of a substance by 1K, while heat capacity does not consider mass and is the amount of heat required to raise the temperature of a substance by 1K. Specific heat capacity includes mass in its calculation and has a consistent, fixed value for a particular substance, while heat capacity can vary for a substance and have the same value for different substances.
An introductory outline of the Physics of Heat. I created this presentation at Curtin Sarawak Malaysia as a basis for Foundation Physics students and others to edit and expand. A Creative Commons Attribution-Share Alike License.
This document provides an introduction to heat transfer. It discusses the key concepts of heat, temperature, thermodynamics and heat transfer. The three main modes of heat transfer are conduction, convection and radiation. Conduction involves the transfer of heat between objects in direct contact. Convection refers to the transfer of heat by the movement of fluids like gases and liquids. Radiation can occur across empty space by electromagnetic waves and does not require a medium. Examples are provided to illustrate each type of heat transfer.
This document discusses different thermal processes involving changes of state:
- Boiling occurs when a liquid absorbs thermal energy and changes to a gas at a constant temperature, breaking molecular bonds. Condensation is the reverse process where a gas releases thermal energy forming liquid bonds.
- Melting absorbs thermal energy at a constant temperature to break solid bonds into liquid. Solidification releases energy forming new solid bonds.
- Evaporation differs from boiling in occurring at any temperature as more energetic molecules overcome surface forces, cooling the remaining liquid. Factors like temperature, pressure and airflow affect evaporation rates.
The set of energy Problems to practice understanding use of q=mCT equation.
Variables and [units]: q - Heat [J]; m - Mass [g]; C - Specific Heat Capacity [J/g*oC or J/g*K]; delta T - change in temperature [oC or K]
This document discusses heat and energy transfer through various physical and chemical processes. It defines key concepts like heat, temperature, endothermic and exothermic reactions, and provides equations and constants for calculating heat transfer and changes in temperature. Practice problems are provided to calculate heat required or lost through changing temperatures of different substances.
This document provides an overview of heat transfer and related topics including:
- The three main modes of heat transfer are conduction, convection, and radiation. Conduction involves the transfer of energy between adjacent particles. Convection involves the movement of heated fluids. Radiation involves the emission and absorption of electromagnetic waves.
- Specific heat capacity refers to the amount of energy required to change the temperature of a material by a certain amount. It varies between materials.
- Thermal conductivity and contact resistance impact heat transfer rates during conduction.
- HVAC systems involve heating, cooling, humidifying, dehumidifying, cleaning, ventilating, and circulating air to control indoor environments.
- Air conditioning expanded the
14 thermal physics thermal properties of matterpranali mankar
This document discusses temperature, heat, and the different methods of heat transfer (conduction, convection, and radiation). It defines temperature as a measure of kinetic energy, and heat as energy transferred between objects at different temperatures. It explains the Celsius, Fahrenheit and Kelvin temperature scales. It then describes conduction as heat transfer through direct contact, convection as heat transfer through fluid movement, and radiation as heat transfer through electromagnetic waves without a medium. It provides examples of each type of heat transfer.
Efficient production of negative hydrogen ions in RF plasma by using a self-b...IJERA Editor
Volume production of negative hydrogen ions is established efficiently in a pure hydrogen RF discharge plasma by using a self-biased grid electrode for production of low electron-temperature and high density plasma. Using this electrode both high and low electron temperature plasmas are produced in the regions separated by the grid electrode in the chamber, in which the electron temperature in the downstream region is controlled by the mesh size and plasma production parameters. The production rate of negative ions depends strongly on the electron temperature varied by the RF input power and hydrogen pressure. In the case of the grid electrode with the 5 mesh/in., the negative hydrogen ions are produced effectively in the downstream region in the hydrogen pressure range of 0.9 −2.7 Pa. In addition, the production rate of the negative ion 퐻 − raises from 62 % to 87 % at 0.9 Pa by changing the RF power from 20 W to 80W.
This document discusses thermal properties of materials. It begins by introducing the group members and outlines for the document. It then defines key concepts like heat capacity, thermal expansion, and thermal conductivity. It explains that metals generally have high heat capacity and thermal conductivity but low thermal expansion. Ceramics have high heat capacity and melting points but low thermal expansion and thermal conductivity. Polymers typically have low densities, heat capacity, thermal expansion, and thermal conductivity. They also have low melting points.
This document provides an overview of heat transfer applications in the oil and gas industry. It discusses key heat transfer methods like conduction, convection and radiation. It also examines how these principles are applied in important industrial equipment like boilers, condensing boilers, piping insulation and heat exchangers. The document aims to explain the importance of heat transfer in petrochemical processes and how different methods are used in applications like heating, cooling, vaporizing and condensing fluid streams.
Thermal expansion, temperature change, and phase change are the three main effects of heat. Thermal expansion causes materials to expand when heated and contract when cooled. The amount of expansion depends on the original length, temperature change, and material's coefficient of linear or volumetric expansion. Temperature change occurs when heat is added or removed from an object, increasing or decreasing its temperature. This temperature change depends on the specific heat capacity of the material, its mass, and the amount of heat added or removed. Phase change involves heat being absorbed or released during changes between solid, liquid, and gas states without a change in temperature. This heat of fusion or vaporization allows materials to change phases.
1. The document discusses measurement of DC resistivity, including specifications for specimen shape and electrode arrangement, materials used for electrodes, and different measuring cell configurations.
2. It also covers partial discharge measurement, defining terms like partial discharge and describing the partial discharge phenomenon in insulation with voids.
3. Breakdown mechanisms in gases, liquids and solids are outlined, focusing on ionization processes in gases which can lead to electrical breakdown at high voltages.
This document discusses different changes of state that matter undergoes. It explains that boiling and condensation involve a transfer of thermal energy without a change in temperature, where boiling transforms liquid to gas and condensation transforms gas to liquid. Melting and solidification also involve thermal energy transfer without temperature change, transforming between solid and liquid. Evaporation differs in that it can occur at any temperature and involves molecules at the surface of a liquid escaping into the air, lowering the liquid's temperature. Factors like temperature, pressure and surface area affect evaporation rates.
When two objects at different temperatures are placed in contact, heat flows from the hotter object to the colder object until they reach the same temperature and are in thermal equilibrium. Thermal equilibrium occurs when the net heat flow between the objects is zero, meaning they are the same temperature. A liquid-in-glass thermometer works by having mercury in a bulb expand up a capillary tube when heated; the distance it travels corresponds to temperature scales defined by fixed points like ice and steam. Mercury is suitable for thermometers because it conducts heat well and expands uniformly with temperature.
1) Evaporation occurs when molecules near the surface of a liquid gain enough kinetic energy to escape, reaching an equilibrium when an equal number return. The boiling point of a liquid is reached when its vapor pressure equals atmospheric pressure.
2) The boiling point of water is 100°C at sea level but varies with altitude and pressure. Raising or lowering pressure by 28 mmHg changes the boiling point 1°C.
3) Thermal expansion causes the volumes of materials to increase with temperature. The degree of expansion varies between materials like brass and steel.
This document contains notes from a Thermal Physics class on various topics:
- Heat flows from hot to cold bodies until thermal equilibrium is reached.
- The Kelvin temperature scale defines absolute zero as 0 K and relates Celsius and Kelvin scales.
- Kinetic theory explains gas properties in terms of molecular motion, assuming molecules are small, hard spheres that collide elastically.
- Internal energy, temperature, heat capacity, phase changes, gas pressure, and the mole concept are defined and related to molecular behavior and properties.
Equations, examples, and questions are provided to illustrate these concepts.
The document discusses heat and thermal equilibrium. It defines key terms like temperature, heat, and thermal contact. It explains that when two objects at different temperatures come into contact, heat is transferred from the hotter object to the cooler one until they reach the same temperature and thermal equilibrium. Examples are given like a wet towel being used to reduce a fever by transferring heat from the body. The document also discusses specific heat capacity and how it relates to how fast an object's temperature changes when heat is gained or lost. Specific heat capacities of different materials are provided.
This document presents a thermoelectric refrigeration system project. It discusses the milestones, realization of the idea, introduction, history and effect of thermoelectric cooling using Peltier modules. It describes the materials, working, dimensions, advantages, drawbacks, applications, cost analysis and conclusion of the project. The project aims to develop a portable thermoelectric refrigerator for preserving insulin in extreme conditions using solar power. It achieves cooling through a single-stage 12V Peltier module and can retain cooling for up to 57 minutes during power outages.
This document presents a thermoelectric refrigeration system project. It discusses the milestones, realization of the idea, introduction to thermoelectric refrigeration and the Peltier effect. It describes the materials used, working of the project including dimensions, advantages, drawbacks, applications, cost analysis, new opportunities, and concludes that the objective of long term cooling in power failures was achieved with a retention time of 57 minutes.
In this paper, new thermal techniques for silicon-based thermoelectric materials were revealed as well as the characterisation processes involved in the manufacturing of silicon-based thermoelectric (TE) materials. The functionality of the silicon-based thermoelectric materials was emphasized in the course of writing this paper. The background, improvement & the physics of thermoelectric materials were examined.
Review on Design and Theoretical Model of Thermoelectricijsrd.com
This paper presents the theoretical development of the equations that allow to evaluate the performance of an air conditioning system based on the thermoelectric effect. The cooling system is based on a phenomena discovered by Jean Charles Athanase Peltier, in 1834. According to this when electricity runs through a junction between two semiconductors with different properties, heat is dissipated or absorbed. Thus, thermoelectric modules are made by semiconductors materials sealed between two plates through which a continuous current flows and keeps one plate hot and the other cold. The most important parameters to evaluate the performance of the device thermoelectric refrigeration are the coefficient of performance, the heat pumping rate and the maximum temperature difference between the hot side and the cold side of the thermoelectric module.
The document discusses cryogenics and its applications. It provides details about a thermal heat switch developed for cryogenic space applications operating near 100 K. The switch uses the difference in linear thermal expansion coefficients of materials to operate. It was designed to separate two pulse tube cold heads cooling a common focal plane array. Testing showed the switch reliably changed states around 220 K with adequate on/off conductivity. Long-term creep testing of the thermoplastic material used found up to 12% reduction in contact pressure after 10 years at 100 K. The switch concept shows promise for redundant cryocooler applications in space.
Performance Evaluation of Thermoelectric Materials: A Case Study of Orthorhom...inventionjournals
Designers often face the predicament of non-standardized and poor performing materials for thermoelectric module manufacturing. Other than analytical means, the only method to evaluate the performance of thermoelectric materials would be through experimental means. This work studies the experimental approach employed in performance investigation of thermoelectric materials using Orthorhombic SnSe crystals as a case study. The result obtained reveals the high thermoelectric conversion efficiency of orthorhombic crystals, and that they can operate as both low and high temperature thermoelectric material.
This document provides information about a project report on refrigeration using a Peltier module. It includes an abstract, introduction, chapters on the basic theory of Peltier devices, materials used, construction and design, working and performance, advantages and disadvantages, cost analysis, and conclusion. The basic theory chapter describes the history of Peltiers, their structure, principles, specifications, applications, heat transport method, doping of semiconductors, and thermoelectric performance factors. It explains how a Peltier module uses the Peltier effect to absorb heat on one side and release it on the other side when a DC current is applied.
Review on Thermoelectric materials and applicationsijsrd.com
In this paper thermoelectric materials are theoretically analyzed. The thermoelectric cooler device proposed here uses semiconductor material and uses current to transport energy (i.e., heat) from a cold source to a hot source via n- and p-type carriers. This device is fabricated by combining the standard n- and p-channel solid-state thermoelectric cooler with a two-element device inserted into each of the two channels to eliminate the solid-state thermal conductivity. The heat removed from the cold source is the energy difference, because of field emitted electrons from the n-type and p-type semiconductors. The cooling efficiency is operationally defined as where V is the anode bias voltage The cooling device here is shown to have an energy transport (i.e., heat) per electron of about500 me V depending on concentration and field while, in good thermoelectric coolers, it is about 50-60 me V at room temperature.
This document discusses waste heat recovery using thermoelectric generators. It begins by introducing the Seebeck effect which allows heat to be directly converted to electricity via a temperature gradient across conductors. The key factors for good thermoelectric materials - high Seebeck coefficient, electrical conductivity and low thermal conductivity - are discussed. Lead telluride is identified as a suitable high performance material for recovering waste heat between 200-600°C. A thermoelectric couple model is analyzed using ANSYS software, showing a voltage of 0.074806V, current of 19.083A and power of 1.4275W can be generated. The summary concludes the analysis demonstrates the potential of thermoelectric generation to recover low grade waste heat as
This document presents a heat response model for a phase layered topology in a photovoltaic thermal (PVT) system. The PVT system is constructed to maximize electrical energy generation through fast removal of heat from PV modules. A new phase layered topology uses combinations of aluminum plates and heatsinks to transfer heat from PV modules to a thermal container. The heat transfer through each layer is investigated with and without water as a coolant. Experimental results show the PV temperature is reduced by around 10 degrees Celsius with this system, which is critical for improving PV performance by reducing wasted thermal energy and increasing electrical energy conversion efficiency.
The document summarizes a student mini project on developing a thermoelectric air conditioning system. The system uses a thermoelectric Peltier module based on the Peltier effect to provide cooling without moving parts. It consists of a 12V Peltier device sandwiched between two heat sinks to dissipate heat, powered by a 12V battery. Fans are used to aid heat transfer. The document discusses thermoelectric principles, components used including specifications, assembly, advantages and limitations. The system was able to lower temperature by 2.11°C with a coefficient of performance of 0.8064 for cooling.
This document discusses the design and analysis of an air-conditioned tricycle that uses thermoelectric cooling. The system uses multiple thermoelectric Peltier modules to absorb heat from the air and provide cooling. Rectangular fins and fiber sheets are used to improve heat transfer from the modules. The design is intended to provide cooling without using ozone-depleting refrigerants. Experimental results showed the thermoelectric system was able to achieve a cooling power of 50W per module with a coefficient of performance between 1.5-2. The document reviews several other studies on thermoelectric cooling systems and their advantages over traditional vapor-compression air conditioners.
Fabrication of Thermo Electric Solar Fridgeiosrjce
IOSR Journal of Mechanical and Civil Engineering (IOSR-JMCE) is a double blind peer reviewed International Journal that provides rapid publication (within a month) of articles in all areas of mechanical and civil engineering and its applications. The journal welcomes publications of high quality papers on theoretical developments and practical applications in mechanical and civil engineering. Original research papers, state-of-the-art reviews, and high quality technical notes are invited for publications.
This document describes the fabrication of a thermoelectric solar fridge. It contains the following key points:
1. A thermoelectric module uses the Seebeck and Peltier effects to generate electrical power from a temperature gradient or convert electrical energy into a temperature gradient for cooling. A solar panel charges a battery through photovoltaic effect, and the battery powers the thermoelectric module.
2. The thermoelectric module is composed of P-type and N-type semiconductors, usually bismuth telluride, between ceramic substrates. When current passes through, it absorbs heat on one side and releases heat on the other, allowing one side to be used for cooling.
This document describes the fabrication of a thermoelectric solar fridge. It contains the following key points:
1. A thermoelectric module uses the Seebeck and Peltier effects to generate electrical power from a temperature gradient or convert electrical energy into a temperature gradient for cooling. A solar panel charges a battery through photovoltaic effect, and the battery powers the thermoelectric module.
2. The thermoelectric module is composed of P-type and N-type semiconductors, usually bismuth telluride, between ceramic substrates. When current passes through, it absorbs heat on one side and releases heat on the other, allowing one side to be used for cooling.
This document discusses different types of heating and welding processes. It describes domestic and industrial applications of electrical heating, including room heaters, immersion water heaters, and electric ovens. It also explains various industrial applications such as metal melting. The document discusses the advantages of electric heating and different temperature control methods for resistance furnaces. It describes different types of heating processes like resistance, arc, induction, and high frequency heating along with their applications.
The document discusses thermoelectric power generators (TEGs). TEGs directly convert thermal energy to electrical energy using the Seebeck effect where an electric current is produced due to a temperature difference across semiconductor junctions. The key components of a TEG are a heat source, thermoelectric module made of p-type and n-type semiconductors, heat sink, and electrical load. Common thermoelectric materials include bismuth telluride, lead telluride, and silicon germanium. TEGs have advantages of being solid state, maintenance free, environmentally friendly, and able to operate in any orientation.
The techniques in which some physical parameters of the systems are determined and /or recorded as a function of temperature.
DSC is a thermal technique in which differences in heat flow into a substance and a reference are measured as a function of sample temperature while the two are subjected to a controlled temperature program.
This document outlines a research project to design a Peltier-based cooling and heating system as an alternative to conventional air conditioning. The objectives are to design and build the cooler section, hot section, and a precise temperature controller. A cost estimation is provided, and the methodology involves collecting materials, designing and fabricating the cooler, and assembling a controller printed circuit board. The intended beneficiaries would be hospitals, universities, and industries in Ethiopia.
Remote Sensing and Computational, Evolutionary, Supercomputing, and Intellige...University of Maribor
Slides from talk:
Aleš Zamuda: Remote Sensing and Computational, Evolutionary, Supercomputing, and Intelligent Systems.
11th International Conference on Electrical, Electronics and Computer Engineering (IcETRAN), Niš, 3-6 June 2024
Inter-Society Networking Panel GRSS/MTT-S/CIS Panel Session: Promoting Connection and Cooperation
https://www.etran.rs/2024/en/home-english/
The technology uses reclaimed CO₂ as the dyeing medium in a closed loop process. When pressurized, CO₂ becomes supercritical (SC-CO₂). In this state CO₂ has a very high solvent power, allowing the dye to dissolve easily.
Current Ms word generated power point presentation covers major details about the micronuclei test. It's significance and assays to conduct it. It is used to detect the micronuclei formation inside the cells of nearly every multicellular organism. It's formation takes place during chromosomal sepration at metaphase.
The ability to recreate computational results with minimal effort and actionable metrics provides a solid foundation for scientific research and software development. When people can replicate an analysis at the touch of a button using open-source software, open data, and methods to assess and compare proposals, it significantly eases verification of results, engagement with a diverse range of contributors, and progress. However, we have yet to fully achieve this; there are still many sociotechnical frictions.
Inspired by David Donoho's vision, this talk aims to revisit the three crucial pillars of frictionless reproducibility (data sharing, code sharing, and competitive challenges) with the perspective of deep software variability.
Our observation is that multiple layers — hardware, operating systems, third-party libraries, software versions, input data, compile-time options, and parameters — are subject to variability that exacerbates frictions but is also essential for achieving robust, generalizable results and fostering innovation. I will first review the literature, providing evidence of how the complex variability interactions across these layers affect qualitative and quantitative software properties, thereby complicating the reproduction and replication of scientific studies in various fields.
I will then present some software engineering and AI techniques that can support the strategic exploration of variability spaces. These include the use of abstractions and models (e.g., feature models), sampling strategies (e.g., uniform, random), cost-effective measurements (e.g., incremental build of software configurations), and dimensionality reduction methods (e.g., transfer learning, feature selection, software debloating).
I will finally argue that deep variability is both the problem and solution of frictionless reproducibility, calling the software science community to develop new methods and tools to manage variability and foster reproducibility in software systems.
Exposé invité Journées Nationales du GDR GPL 2024
The use of Nauplii and metanauplii artemia in aquaculture (brine shrimp).pptxMAGOTI ERNEST
Although Artemia has been known to man for centuries, its use as a food for the culture of larval organisms apparently began only in the 1930s, when several investigators found that it made an excellent food for newly hatched fish larvae (Litvinenko et al., 2023). As aquaculture developed in the 1960s and ‘70s, the use of Artemia also became more widespread, due both to its convenience and to its nutritional value for larval organisms (Arenas-Pardo et al., 2024). The fact that Artemia dormant cysts can be stored for long periods in cans, and then used as an off-the-shelf food requiring only 24 h of incubation makes them the most convenient, least labor-intensive, live food available for aquaculture (Sorgeloos & Roubach, 2021). The nutritional value of Artemia, especially for marine organisms, is not constant, but varies both geographically and temporally. During the last decade, however, both the causes of Artemia nutritional variability and methods to improve poorquality Artemia have been identified (Loufi et al., 2024).
Brine shrimp (Artemia spp.) are used in marine aquaculture worldwide. Annually, more than 2,000 metric tons of dry cysts are used for cultivation of fish, crustacean, and shellfish larva. Brine shrimp are important to aquaculture because newly hatched brine shrimp nauplii (larvae) provide a food source for many fish fry (Mozanzadeh et al., 2021). Culture and harvesting of brine shrimp eggs represents another aspect of the aquaculture industry. Nauplii and metanauplii of Artemia, commonly known as brine shrimp, play a crucial role in aquaculture due to their nutritional value and suitability as live feed for many aquatic species, particularly in larval stages (Sorgeloos & Roubach, 2021).
EWOCS-I: The catalog of X-ray sources in Westerlund 1 from the Extended Weste...Sérgio Sacani
Context. With a mass exceeding several 104 M⊙ and a rich and dense population of massive stars, supermassive young star clusters
represent the most massive star-forming environment that is dominated by the feedback from massive stars and gravitational interactions
among stars.
Aims. In this paper we present the Extended Westerlund 1 and 2 Open Clusters Survey (EWOCS) project, which aims to investigate
the influence of the starburst environment on the formation of stars and planets, and on the evolution of both low and high mass stars.
The primary targets of this project are Westerlund 1 and 2, the closest supermassive star clusters to the Sun.
Methods. The project is based primarily on recent observations conducted with the Chandra and JWST observatories. Specifically,
the Chandra survey of Westerlund 1 consists of 36 new ACIS-I observations, nearly co-pointed, for a total exposure time of 1 Msec.
Additionally, we included 8 archival Chandra/ACIS-S observations. This paper presents the resulting catalog of X-ray sources within
and around Westerlund 1. Sources were detected by combining various existing methods, and photon extraction and source validation
were carried out using the ACIS-Extract software.
Results. The EWOCS X-ray catalog comprises 5963 validated sources out of the 9420 initially provided to ACIS-Extract, reaching a
photon flux threshold of approximately 2 × 10−8 photons cm−2
s
−1
. The X-ray sources exhibit a highly concentrated spatial distribution,
with 1075 sources located within the central 1 arcmin. We have successfully detected X-ray emissions from 126 out of the 166 known
massive stars of the cluster, and we have collected over 71 000 photons from the magnetar CXO J164710.20-455217.
Or: Beyond linear.
Abstract: Equivariant neural networks are neural networks that incorporate symmetries. The nonlinear activation functions in these networks result in interesting nonlinear equivariant maps between simple representations, and motivate the key player of this talk: piecewise linear representation theory.
Disclaimer: No one is perfect, so please mind that there might be mistakes and typos.
dtubbenhauer@gmail.com
Corrected slides: dtubbenhauer.com/talks.html
ESR spectroscopy in liquid food and beverages.pptxPRIYANKA PATEL
With increasing population, people need to rely on packaged food stuffs. Packaging of food materials requires the preservation of food. There are various methods for the treatment of food to preserve them and irradiation treatment of food is one of them. It is the most common and the most harmless method for the food preservation as it does not alter the necessary micronutrients of food materials. Although irradiated food doesn’t cause any harm to the human health but still the quality assessment of food is required to provide consumers with necessary information about the food. ESR spectroscopy is the most sophisticated way to investigate the quality of the food and the free radicals induced during the processing of the food. ESR spin trapping technique is useful for the detection of highly unstable radicals in the food. The antioxidant capability of liquid food and beverages in mainly performed by spin trapping technique.
ESR spectroscopy in liquid food and beverages.pptx
Thermoelectric Panels
1. INTERN REPORT
TOPIC :
SYNTHESIZING THERMOELECTRIC MATERIALS AND MAKING PANELS
NAME :
DEEPANSHU BHATIA
ENTRY NO. :
2012PH10837
PROFESSOR :
CHESTA RUTTANAPUN
GUIDE :
HAI RUDRADAWONG
INSTITUTE :
KING MONGKUT INSTITUTE OF TECHNOLOGY LADKRABANG , BANGKOK
2. PREFACE
This report documents the work done during the summer internship at
Thermoelectric LaboratoryofKing Mongkut Institute ofTechnology Ladkrabang
(KMITL), Bangkok, Thailand under the supervision of Prof. Chesta Ruttanpun.
The report first shall give an overview of the tasks completed during the period
of internship with technical details. Then the results obtained shall be discussed
and analyzed. Report shall also elaborate on the the future works which can be
persuaded as an advancement of the current work.
Deepanshu Bhatia
2012PH10837
3. ACKNOWLEDGEMENT
The internship opportunity I had with KMITL was a great chance for learning
by practical experiences. I am also grateful for having a chance to meet so many
wonderful people and professionals who led me though this internship period.
I am using this opportunity to express my deepest gratitude and special thanks
to Prof. Wichit Sirichote to guide me at their esteemed organization during the
training.
I express my deepest thanks to Prof. Chesta Ruttanpun and Hai Rudradawong
[Phd Student] for taking part in useful decision making & giving necessary
advices and guidance and arranging all facilities to make the project go
smoothly. I choosethis moment to acknowledge his contribution gratefully.
I will strive to use gained skills and knowledge in the best possible way, and I
will continue to work on their improvement, in order to attain desired career
objectives. Hope to continue cooperation with all of you in the future.
Sincerely,
Deepanshu Bhatia
4. ABSTRACT
The report presents the four tasks completed during summer internship at
KMITL which are listed below:
1) Synthesis of Thermoelectric Material from Solid state
reaction process.
2) Making Pellets from thermoelectric powder using Hydraulic press.
3) Making Thermo-electric panel of different sizes.
4) Testing of thermoelectric Panels.
All these Tasks have been completed successfully and the results obtained were
according to expectations with some minor errors.
Also during the evaluation of pellets it was found that the pellet’s finishing
depends not only on the quality of fine powder but also on the pressure applied
on it in hydraulic press and the time for which it is kept.
We had limited testing facilities. Panel could be heated only upto 200 C. Glue
used in the panels could only withstand up to 100C. Also we did not have the
required equippments to test for Seebeckcoefficient. So, we have a limited scope
to test the panels and sure we have exhausted the opportunities to maximum
extent.
5. INTRODUCTION
Thermoelectric substances :
Thermoelectric substances can be used to produce electric current from heat and
also cooling and heating from electric current.
When a conductive material is subjected to a thermal gradient, charge carriers
migrate along the gradient from hot to cold; this is the Seebeck effect. In the open-
circuit condition, charge carriers will accumulate in the cold region, resulting in the
formation of an electric potential difference.
The Seebeck effect describes how a temperature difference creates charge flow,
while the Peltier effect describes how an electrical current can create a heat flow.
Electrons transfer heat in two ways:
1) by diffusing heat through collisions with other electrons, or
2) by carrying internal kinetic energy during transport.
The former case is standard heat diffusion, while the latter is the
Peltier effect. Therefore, the Seebeck effect and the Peltier effect are the opposite of
one another.
The thermoelectric effect is the fact that a temperature gradient in a conducting
material results in heat flow , this results in the diffusion of charge carriers. The
flow of charge carriers betweenthe hot and coldregions in turn creates a voltage
difference.
Basic Physics Behind the experiment:
6. When an end of a thermoelectric material is heated up, electrons in the warmer side
of material have more energy. Since they are free to move, the excited electrons diffuse
toward the colder side of the thermocouple leaving holes behind.
The electric field develops by the movement of these electrons point towards the
colder side of the thermoelectric material which makes the cold side negative relative
to the warmer side. The electrons will keep moving toward the colder side until the
potential established by the charge separation counteracts the flow of electrons which
creates equilibrium.
S = [ V(Plate1) – V(Plate2) ]
---------------------------------------------------
[ T(Plate1) - T(Plate2) ]
Therefore, One can say that to obtain a high power output from thermoelectric
material , the potential difference obtained should be higher for minimum temperature
difference , i.e the Seebeck Coefficient of a material should be higher for good results.
Delafossite structure and its significance :
Delafossite is a copper iron oxide mineral with formula CuFeO2 . . It is member of the
delafossite mineral group with a general formula ABO2, a group characterized by a
sheet of linearly coordinated A cations stacked between edge-shared octahedral layers
(BO6). Delafossite along with other minerals of the ABO2 group has been recognized
for its electrical properties from insulation to metallic conduction.
By heating the given sample at the specified temperature for the given time we get
delafossite structure of the compound. Our compound is not CuFeO2, but it contains
substituted Cr in the delafossite CuFeO2 to see the effect of Cr content on the
thermoelectric properties.
7. METHODS AND PROCEDURES
FOLLOWED
Synthesis of thermoelectric Substances, fabrication and testing of Thermo-
electric panels
Part 1 :
Synthesis of thermoelectric Substances
We synthesised thermo-electric substances from chemicals. We mix the required
chemical compounds in the required proportion. Then we followed the following
procedures to get our thermoelectric material prepared in powdered form.
1. Ball milling :
After mixing the compounds we put the mixture in a container with milling
balls. The milling balls are of different sizes and help to mix the compound
and make a fine powder mixture. Put all the contents into a plastic container
along with the milling balls and ethanol and put the container for milling for
24 hours. Ethanol does not react chemically with the compounds, it just
provides a medium for the milling balls to mix the substance properly. After
24 hours the milling is over we get a solution of the mixture of fine powder
with ethanol.
2. Heating in heater:
After ball-milling we need to remove the ethanol. So, we put our compound in
a heater at about 90-100 C for 24 hours. The ethanol evaporates leaving
behind the properly mixed compounds. Till now it is mixed uniformly but not
in fine powdered form. We have to manually crush it by using mortar and
pestle to very fine powder before the next step. After, it gets converted to very
8. fine powder we move to the next step. We have to crush each sample for
about 1-2 hours to get very fine powder using two type of mortar and pestle.
3. Chemical reaction in oven :
Now comes the main transformation. This mixture is now heated at a specific
temperature under certain conditions to get the required delafossite structure.
We heat the sample at 1050 C for 20 hours in an electrical oven. The
temperature vs time graph programmed in the oven is as follows :
0
200
400
600
800
1000
1200
0 5 10 15 20 25 30
Y-Values
9. Heating Electric Oven:
The oven rose from room temperature to required set temperature 1050 C in
3 hours then it stays at that temperature for 20 hours and then we take out
the sample at this temperature to room temperature quickly to allow
quenching.
After cooling down the sample at room temperature we get a hardened solid
mass of the required thermoelectric substance. Now using the bigger mortar
and pestle crush it into smaller pieces and then more fine pieces, finer powder
and the very fine. It takes a lot of
time about 6-7 hours to crush it into final usable fine powder.
10. Mortar and pestle :
This final fine powder is our thermoelectric substance.
Part 2:
Making the pellet
Now, using the fine powder we can create thermoelectric pellets of different
shapes from cylindrical or cubical. We are considering only cylindrical ones.
We use iron moulds to make these pellets. Moulds look like this :
11. Using the moulds and applying a pressure of 9-12 *(10^6) Pascal, we get our pellets.
We use a hydraulic press for the purpose :
12. We make pellets of different sizes to compare their properties. Right now the pellet is
just compressed powder and it’s not very strong. We again repeat the heating in
oven step to make them strong. The pellets were sintered in furnance at 1050 C
under air atmosphere for 24h. After heat treatment the sample was rapidly quenched
at room temperature. Now these pellets are ready to use in our thermoelectric panel.
Pellets :
Part 3 :
Making the panel
To make the panel we have to keep the pellets in a grid pattern with a*b
pellets.
The base and head of panel are either made of ceramic thermally conducting
substance or metallic plates (zinc).
First we make a series connection between the pellets using copper plates.
These copper plates are joined with the pellets with conducting glue (Glue 1).
13. After this connection the pellets are connected in series such that when the
whole system is placed between temperature gradients the thermoelectric
currents of all the pellets add up. The connection made with this glue have to
be kept in open at room temperature for 2-3 days. After that it was kept for 1
day in heater at 100 C.
Connecting the pellets in series using copper plates and copper wires :
After making the pellets in series this whole grid like system has to be joined
to the ceramic or metallic plates. The glue (Glue 2) used is thermally
conducting and electrically insulating. In case of metallic plate panel we have
to be very careful because any error in insulating glue can lead to short
circuiting the whole panel with zinc plates on top and bottom, hence
hampering the performance. To ensure that the glue is properly applied it has
to be dried one day in room temperature and subsequent day in oven at 100
C. After these procedures ensure that all connections are properly made and
no connection is short circuited by any of glue thermally or electrically.
Panel (with ceramic base ) :
16. Part 4 :
Testing the panel
To test the panel we apply a finite temperature gradient and measure the
series current of the panel.
We first measure the resistance of the panel at room temperature. Then apply
an external resistance equivalent to this in our circuit. Add an ammeter in
series, voltmeter in parallel and then gradually increase the temperature
gradient and observe the change in current.
The colder junction is maintained by keeping ice on it and hotter one by using
heater.
This way we get the readings and plot the graph for various panel of different
grid configurations, different thermoelectric substance, different heights of
pellets and get our conclusions.
17. Observations and Results:
From the above process we prepared Two different kind of thermoelectric substance
1) Cu Fe 0.75 Cr 0.25 O 2 (Sample 1)
2) Cu Fe 0.9 Al 0.1 O 2 (sample 2)
And from these two substances we prepared total 6 Modules
3 From sample 1 and 3 from Sample Two as Follows
*here parameter used to compare the size of pellet is weight (in grams) of pellet
because the height is directly proportional to wt., as other conditions like pressure,
temp. were identical during its manufacturing.
From Sample 1:
Module No. Pellet’s weight (in
gm of sub. filled )
Type of Plates used
Sam1 Mod a 4gm Ceramic
Sam1 Mod b 4gm Metallic
Sam1 Mod c 5gm Ceramic
From Sample 2:
Module No. Pellet’s weight (in gm of
sub. filled )
Type of Plates used
Sam2 Mod a 2gm Metallic
Sam2 Mod b 3gm Metallic
Sam2 Mod c 6gm ceramic
For testing the module’s performance, we prepared a following setup by applying a
temp gradient on the opposite sides of modules we measured the output current as a
function of temperature Gradient.
Case 1: Sam1 Mod a
Bottom Surface
Temp
Top Surface Temp
(in C)
Temp gradient Current Output
( in uA)
18. ( in C)
21.5 13 8.5 21
30 17 13 32
42.4 21.3 21.1 50
56 24.8 31.2 58
69 30.6 38.4 65.3
83 28.5 54.5 76.9
93 31 62 86.7
Case 2: Sam1 Mod b
BottomSurface
Temp
( in C)
Top Surface
Temp
(in C)
Temp gradient Current
Output
( in uA)
70 30 40 58
80 35 45 72
115 28 87 163
130 45 90 191
150 50 100 203
Case 3: Sam1 Mod c
Bottom Surface
Temp
( in C)
Top Surface
Temp
(in C)
Temp gradient Current Output
( in uA)
46 13 33 110
55 18 37 120
56 18.4 37.6 123
71.6 22 49.6 172
84.4 32 52.4 192.2
103.3 34 69.4 246
125 50 75 279
135 55 80 300
Case4: Sam2 Mod a
Bottom Surface Temp
( in C )
Top Surface Temp
(in C)
Temp gradient Current Output
( in uA)
45 20 25 11
60 27 33 12
77 32 45 15
19. Case 5: Sam 2 Mod c
Bottom Surface
Temp
( in C)
Top Surface Temp
(in C)
Temp gradient Current Output
( in uA)
35.5 13.5 22 95.7
47.5 20.5 27 114.8
60 30.4 29.6 160
70 34 36 180
68 30.2 37.8 212
73 32 41 241
105 42 63 280
108 40 68 323
124 50 74 345
131 40 91 382
# Note: Out of all modules two Modules (Sam 2 Mod 1, Sam 2 Mod 2) were defective
as we can see from the readings that the output current is very low and not increasing
with increase in gradient and also the Internal Resistance is not as per the expectation
there might be some short circuiting in the module.
Conclusion:
From the above results one can conclude that the Current output of modules increases
with increase in Temp. Gradient, i.e Temp gradient is providing an electromotive force
implicitly.
Other conclusion which can be drawn from the results is that the two modules named
as Sam2 Mod a, Sam 2 Mod b were defective, may be the conducting glue
(electrically) had made a contact between the top and bottom plates or maybe there
was an electrical contact between the metallic plates and the pellets due to which the
total internal resistance was too low and the whole module was short circuited.
The thermally conducting glue used to connect pellets with the plates was not a good
choice to be used in our modules because as we reached at temp. around 130 C the
thermally conducting glue( Fiber Adhesive) started to break. Due to which we had
to limit ourselves to Max limit of 130-150 C, and got the Maximum Current readings
till this Temp range only.
Also max. Current for a module was more in case of module where large pellet (larger
in length) of same material were used.
20. We got the Max current for module named as Sam 2 Mod c of 382 uA ( i.e for Sample
2) , that too at Temp gradient of 91 C , but if we had some better Thermally conducting
glue that can with stand in Temp range of 400-500 C than , we would have got a far
better readings.
Scope of Improvement in Future:
We tried a very new concept of using a Metallic plates instead of Ceramic Plates in the
Modules and as result we got enhanced values of Max . current (almost Twice)
through the Metallic Plates Modules than from the Ceramic plates module.
We also tried to decrease the heat conduction between top and Bottom plates (as it
degrades the Temp gradient produced by heating one side) by replacing the copper
plates used to connect the pellets in series by copper wires, but unfortunately due
to some manufacturing errors the circuit got short circuited and we were not able to
take the real readings of modules and we didn’t have enough time in the end to make
that type of module again but I think is proper care is taken while joining the pellets
with copper wires instead of copper plates , the heat conduction can between two
plates can be reduced upto an extent and we can get high temp gradient by heating
upto a small range of Temp.
Sources Of Error:
During the preparation of pellets the powder was kept in a ceramic dish for days
wrapped in Al Foil, due to which after some time moisture got into it and when
we made pellets from that moisturized powder they we not as good in finishing
as the one made by dry powder.
Also some times the pressure applied to Dies kept in Hydraulic Press to make
Pellets was not same in each case some time it dropped to half of its actual
value which might have brought non uniformity in pellets.
21. While preparing modules and joining pellets with copper plates and electrically
conducting glue there were instances when electrical glue spread over the pellet
to get is short circuited.
While applying thermally conducting Glue sometimes there were direct
contacts made between top and bottom plates by the overflow of glue.
And there are manual error also while measuring the readings like contacts are
not made proper while connecting external circuits.
# If these all errorsarehandled properlyandthe new methodswe tried like using metallic
plates and copper wires and using a high temp. resistant glues, we can reach to a whole
new level of Thermoelectricity in Future.
REFERENCES :
Wikipedia : Thermoelectric substances
Research paper on Thermoelectric properties of Sn+2 –
Substituted CuFeO2 Delafossite-Oxide (Advanced Materials
Research Vol. 802(2013) pp 17-21 ,
doi:10.4028/www.scientific.net/AMR.802.17)