The current may be produce from heating, magnetic, chemical, lighting etc. A teg is based on the principle of the seebeck effect and converts thermal energy into electrical power. Both effects showed strong dependence on the direction of h, reflecting inplane magnetization reversal process. The nps institutional archive theses and dissertations thesis collection 199212 thermoelectric cooler design clifton, william earle monterey, california. Thermopower measurements and electronphonon coupling.
The purpose of this research is to measure seebeck coe cient of various metals and semiconductors in a room temperature. Thermoelectric generators tegs convert the thermal energy flowing through them into dc electrical energy in a quantity dependant on the temperature difference across them and the electrical load applied, with a conversion efficiency of typically 5%. The electromotive force that was generated was named the seebeck effect. Schematic of the sample layouts, used for spin seebeck effect. Seebeck effect, production of an electromotive force emf and consequently an electric current in a loop of material consisting of at least two dissimilar conductors when two junctions are maintained at different temperatures. As a result of the above, the four thermoelectric effects are correctly attributed the following names. Seebeck and peltier effects university of mississippi. The conductors are commonly metals, though they need not even be. Thermoelectrics are based on the seebeck effect, stating that a voltage is induced when a temperature gradient is applied to the junctions of two differing materials. Sadi turgut january 2004, 69 pages the electrical and thermal conductance and the seebeck coe. The seebeck effect the seebeck effect, or thermoelectric effect direct conversion of temperature differences into electricity discovered in 1821 by thomas johann seebeck found that a voltage existed between two ends of a metal bar. The basic theory behind this teg is seebeck effect. In our daily life we come accross a number of devices based on effect of electric current.
Schematics of a 2d inhomogeneous sample connected by. Thermoelectricity, direct conversion of heat into electricity or electricity into heat through two related mechanisms, the seebeck effect and the peltier effect. Conversely, when a voltage is applied to it, heat is transferred from one side to the other, creating a temperature difference. Graduate thesis or dissertation seebeck coefficient in. Design of a solar thermoelectric generator undergraduate. Polycrystalline silicon sample was prepared by crushing, ballmilling and hot pressing a. The voltage produced causes current flow through the electrical load, thereby providing electrical power. Design, modeling and simulation of a thermoelectric. The design and construction of two experimental setups to. In 1821, thomas seebeck discovered that an electromotive force could be generated when a circuit was made out of two dissimilar materials and when the junction was heated.
This master thesis is completed for the degree of master in technology in renewable energy at the department of engineering and science, university of agder, grimstad campus. Modeling and application of a thermoelectric generator. Project report on thermoelectric effect or seebeck effect physics project on seebeck effect introduction. Variable temperature seebeck measurement systems mmr technologies, inc. Optimization studies were performed to determine the e ect of system size, exhaust and coolant ow conditions, and thermoelectric material. Thesis submitted in partial fulfillment of the requirements for the degree of master of science in mechanical engineering in the graduate college of the. To study the behavior of the vortex motion, different temperature gradients, different sample dimensions, and different. The thermoelectric power cycle, with charge carriers serving as the working fluid, follows the. Peltier effect when operated as a generator, one side of the device is heated to a temperature greater than the other side, and as a result, a difference in voltage will build up between the two sides. The views expred in this thesis are those of the author and do not reflect the official policy or position of the department of defense or the us. This proportion is known as the peltier coefficient. Peltier effect in 1834, a french watchmaker and part time physicist, jean peltier found that an electrical current would produce a temperature gradient at the junction of two dissimilar metals. When two metals are placed in electric contact, electrons flow out of the one in which the electrons are less bound and into the other.
The work described in this thesis was performed in the research group physics of nanode vices of the. Energy can be recovered by evaporation and expansion of the gas. Thermoelectric property study of ntype pbte by a thesis. Peltier effect jean charles athanase peltier 17851845 peltier effect.
Thermoelectric effect, materials, measurement and application energy conservation, use and efficiency are increasing important issues in the daily lives of all people in the modern world. Thermoelectric materials convert temperature differences into electricity and vice versa. Seebeck 17701831 discovered that dissimilar metals that are connected at two different locations junctions will develop a microvoltage if. Apr 21, 2012 seebeck effect the seebeck effect is the conversion of temperature differences directly into electricity it is named after german physicist thomas johann seebeck in 1821 he discovered that a compass needle would be deflected by a closed loop formed by two metals joined in two places, with a temperature difference between the junctions. Advanced science research center, japan atomic science agency, tokai, japan. When a temperature difference is recognized between the hot and cold junctions of two dissimilar materials metals or semiconductors a voltage is generated, this voltage is called seebeck voltage. Further detailed derivations of the seebeck coefficient can be found in numerous. Linearresponse approach to the magnondriven spin seebeck effect 7 5. Preliminary design of a cryogenic thermoelectric generator. Seebeck effect, the peltier effect and the thomson effect. Local picture of thermal spin injection by magnons 5 5.
In the seebeck effect, a temperature gradient across a material causes the diffusion of charged carriers across that gradient, thus creating a voltage difference between the hot and cold ends of the material. Thermoelectric effect, materials, measurement and application. Development in spin seebeck devices maekawa goup jaea, saitoh group tohoku university, ibarra group university of zaragoza. Smart power generation from waste heat by thermo electric generator 46 generate electricity by using thermoelectric generator. Thermopower measurements and electronphonon coupling in molecular devices thesis submitted for the degree of doctor of philosophy by ilan yutsis submitted to the senate of. A thermoelectric power generator is a solid state device that provides direct energy conversion from thermal energy heat into electrical energy based on seebeck effect. Room temperature seebeck coe cient measurement of metals and. Investigation of lowgrade thermal energy harvesting using. In this work a thermoelectric generator teg system simulator was developed to perform various parametric and.
This process was discovered in 1834 by scientist named peltier, and thus it is called the peltier effect. Thermoelectric generator from space to automotive sector. The thermal gradient is applied in zdirection, the spin current is. Thermopower, or historically the seebeck effect, consists of the generation of an electric field, e, in the presence of a temperature gradient. Peltier effect and seebeck effect are calculated by applying a reversible closed carnot cycle, and thomson effect by the boltzmann transport equation. This is what causes wires to heat up when current runs through.
Charles peltier and william thomson lord kelvin gave the effects their names. This thesis focuses on the characterization of a thin. Learn how this effect has been applied to generate power, develop thermal sensors, and some advanced areas of its application. This is important features of thermoelectric effects. It is determined that the double occupancy term in the grand partition function dominates any single occupancy contribution, thus the theoretical result for the temperaturedependent seebeck coefficient for this system is a function of an intercalated atom concentration term. Thermoelectric power generation is based on solid state technology with no moving parts and works on the principle of seebeck e ect. In the seebeck effect, a temperature gradient across a material causes the diffusion of charged carriers across that gradient, thus creating a voltage difference between the hot and cold ends of the. A numerical model for a teg was developed and applied to the exhaust gas system of both, a commercial and a heavy duty vehicle. This thesis develops the firstprinciples simulation tools to study the phonon drag effect a coupling phenomenon between electrons and nonequilibrium phonons that leads to a large seebeck coefficient at low temperatures. The magnetic devices that are used consist of two ferromagnetic strips connected by a nonmagnetic metal, thereby forming a socalled nonlocal spin valve. Pdf thermoelectric effect peltier seebeck and thomson.
There are three major effects involved in a thermocouple circuit. The seebeck effect is a phenomenon in which a temperature difference between two dissimilar electrical conductors or semiconductors produces a. Making liquid nitrogen ln2 is a method of storing energy. Discovered in 1834 an electrical current creates a cooling or heating effect at the junction depending on the direction of current flow. Thermo electric effect seebeck effect, project report. In a cryogenic thermoelectric generator, the load is connected at the hot end for ease of connection. T h t c temperature difference between hot and cold junctions. The first part of the thermoelectric effect, the conversion of heat to electricity, was discovered in 1821 by the estonian physicist thomas seebeck and was explored in more detail by french physicist jean peltier, and it is sometimes referred to as the peltier seebeck effect. The first major outcome is a demonstration of how the seebeck coefficient can be used as a tool to quantify the role of energetic disorder in organic semiconductors. Most of the derivations in the rst three sections of this chapter are taken from refs. Project report on thermoelectric effect or seebeck effect. This is a dummy text this is a dummy text the undersigned have examined the thesis entitled modeling of an automotive exhaust thermoelectric generator presented by a dummy textmadhav a karria dummy text, a candidate for the.
Theory of the spin seebeck effect fb physik, fu berlin. Electricalthermal analogues are often employed when studying heat. University of oslo department of physics thermoelectric hybrid materials master thesis 60 credits by. The process in which electrical energy is transformed into thermal energy is called joule heating. In chapter 2, we discuss the sample preparation and ion beam sputtering process. More specifically, the elimination of minority carriers provide a beneficial effect by maintaining the high value of the seebeck coefficient as a result of the decreasing effect of the minority charge carriers. Peltier effect 1834 the reverse of the seebeck effect is also possible. Thermoelectric devices create a voltage when there is a different temperature on each side. First principles study of thermoelectric properties of zincoxide nanowires thesis presented to the graduate council of texas state universitysan marcos in partial fulfillment of the requirements for the degree master of science by peter d. Seebeck effect was discovered by thomas seebeck in 1821. This thesis explains the theory behind the seebeck e ect, describes the apparatus used to measure seebeck coe cient at room temperature, presents experimental values of sc for common alloys, metals, semiconductors and discusses. Thermoelectric properties of bismuth and silicon nanowires. The seebeck effect in conductors and semiconductors has been explained vividly to give the reader a complete understanding.
To this end, a microfabricated chip was designed to perform accurate measurements of the seebeck coefficient within the channel of the active layer in a field effect transistor fet. Graduate thesis or dissertation seebeck coefficient in the. This may sound similar to joule heating described above, but in fact it is not. The seebeck effect describes the voltage or electromotive force emf induced by the temperature difference gradient along the wire. In this article we propose a simple and lowcost experimental setup through which science educators can demonstrate the seebeck effect using a thermocouple and an instrumentation amplifier. This thesis could not have been done without your expertise. The thermoelectric effect is the direct conversion of temperature differences to electric voltage and vice versa via a thermocouple. Heat is produce when a current pass through a conductor. Modeling and application of a thermoelectric generator david yan masters of applied science graduate department of electrical and computer engineering university of toronto 2011 thermoelectric modules are an important alternative to heat engines in the harvesting of waste heat. The experiment can be set up and conducted during a 1hour laboratory session. Seebeck effect when the two junctions of a pair of dissimilar metals are maintained at different temperatures, there is the. In this work a thermoelectric generator teg system simulator was developed to perform various parametric and system optimization studies. Recent increases in energy costs here in the united states, industrial growth throughout the world, plus the.
Experimental details of the spin seebeck effect 5 5. Thermoelectric materials have drawn vast attentions for centuries, because thermoelectric effects enable direct conversion between thermal and electrical energy, thus providing an alternative for power generation and refrigeration. Aruna dedigama for helping me fix the inconsistencies with my understanding of thermoelectrics as well as providing his valuable time and effort to grow the material researched in this thesis. Waste heat energy harvesting using thermo electric generator. The term thermoelectric effect encompasses three separately identified effects. Effect 2 is the peltier effect and is correctly identified as the reverse of the seebeck effect. S the voltage generated depends on the seebeck coefficient s and the temperature difference between the two junctions in the thermocouple, as seen in equation 1. Temperature of inversion is the temperature of hot junction at which the thermo e. When a current flows through the junction, heat is either gvierated or absorbed depending on the direction of the current flow. T s is the thermopower coefficient, in a conductor under the condition of zero net current. Such materials utilize the seebeck effect for power generation and the peltier effect for refrigeration.
The seebeck effect material 1 material 2 material 2 hot reservoir t h cold reservoir t c v open circuit voltage, v. Seebeck and peltier effects a discussion of thermoelectric effects and devices should start with one of the most fundamental te phenomena, the seebeck effect, or thermopower. We present a microscopic model of the seebeck effect based on a generalized drift. The seebeck effect is the production of emf, electromotive force, with junctions of two different conductors. Effects 3 and 4 together comprise both directions of the thomson effect. Nonetheless, they can be successfully employed to recover energy from waste heat and their use has increased rapidly in recent years, with. The spin seebeck effect refers to the generation of a spin voltage caused by a temperature gradient in a ferromagnet, which enables the thermal injection of spin currents from the ferromagnet into an attached nonmagnetic metal over a macroscopic scale of several millimeters. The peltier effect dictates that the amount of heat created or lost at a junction is proportional to the electrical current applied to it. University of groningen thermoelectric effects in magnetic. Seebeck 17701831 discovered that dissimilar metals that are connected at two different locations junctions will. A simple explanation of seebeck effect with its applications. Design, modeling and simulation of a thermoelectric cooling. The seebeck effect was discovered almost 200 years ago, but in the.
Two junctions connected back to back are held at two different temperatures t h and t. Seebeck and peltier effects introduction thermal energy is usually a byproduct of other forms of energy such as chemical energy, mechanical energy, and electrical energy. The spin seebeck effect refers to the generation of a spin voltage caused by. Thesis high efficiency thermoelectric devices fabricated using quantum well confinement techniques submitted by austin lee jurgensmeyer department of mechanical engineering in partial fulfillment of the requirements for the degree of master of science colorado state university fort collins, colorado summer 2011 masters committee. The seebeck effect the longitudinal thermopower and the inplane nernst effect the transverse thermopower under inplane h were measured on compressive ga,mnas. For a given thermocouple it is a fixed temperature. The seebeck and peltier effects are different manifestations of the same physical process. Seebeck effect consider the junction of two materials, a and b. The kelvin relations are the link between all three thermoelectric effects. Seebeck effect the seebeck effect is the conversion of temperature differences directly into electricity it is named after german physicist thomas johann seebeck in 1821 he discovered that a compass needle would be deflected by a closed loop formed by two metals joined in two places, with a temperature difference between the junctions. Jst japanspain meeting march 5, 20 sadamichi maekawa. They also decrease the seebeck coefficient, carrier concentration. Interplay of peltier and seebeck effects in nonlocal spin valves in chapter 3, the conventional peltier and seebeck effects have been investigated in magnetic nanostructures.
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