Thermoelectric power generation

Abstract

Thermoelectric generators have no moving parts, are silent in operation and are compact, and, when coupled to an isotropic heat source, can operate unattended over long periods in inhospitable and inaccessible environments. In recent years, thermoelectric generators have found increased application in situations where combinations of their desirable properties outweigh their relatively high cost and low generating efficiency. This paper reviews the present 'state of the art' of generating electricity by the thermoelectric effect and looks at future prospects. A brief history of thermoelectricity is followed by definitions and an introduction to its basic theory. Factors that influence the selection of materials for a particular application are discussed, together with the preparation and properties of established materials. A Section dealing with the fabrication of thermoelements and the various configurations employed in module construction is followed by a general discussion of thermoelectric generators. These are divided into two types: nonisotopic powered and isotopic powered. Emphasis is placed on the latter, and applications of this type of generator are covered in some detail. The conclusion is reached that the development and application of thermoelectric generators is assured with the continuation of the US space programme, with radioisotopic thermoelectric generators (r.t.g.s) providing onboard power for deep-space missions. In marine applications, the requirement for isotopic-powered generators in submerged situations will increase, whereas their prospects in surface and terrestrial applications is not so certain. From an economic point of view, it seems unlikely that the use of radioisotopic generators can be justified in situations where air is available to burn hydrocarbon fuel. In situations where it is difficult to get fuel to the site, a thermomechanical generator provides a possible alternative to thermoelectric generators. In medical applications, particularly the nuclear-powered cardiac pacemaker, the future is more promising. Less risk to the patient results from the use of a nuclear-powered pacemaker than from chemical batteries, and, as for environmental objections, the Fuel Directorate of Licensing have made it clear that their social and economic benefits far outweigh the social and economic costs. IntroductionExploration of space, advances in medical physics and the exploitation of the earth's resources in increasingly hostile and inaccessible locations has been accompanied by a requirement for autonomous sources of electrical power. Thermoelectric generators are ideally suited to such applications; they are compact, have no moving parts and are silent in operation. In situations where periodic refuelling is possible and oxygen available, fossil fuel is employed as a heat source. Hydrocarbon fuel has an energy density some fifty times that of a chemical battery, and so, provided that the conversion efficiency is better than 2%, a hydrocarbon-fuelled system can provide a much lighter and ...

Battery charging considerations in small scale electricity generation from a thermoelectric module

“…However, the heat input to the module, QH, creates a temperature difference across the p-n thermoelements. The Seebeck effect is described by Rowe [13]. The free carriers at the hot end have greater kinetic energy and diffuse to the cold end.…”

Small scale electricity generation from a portable biomass cookstove: Prototype design and preliminary results

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Growth and thermoelectric properties of CaMnO3-based thin films

“…[1][2][3][4] The effect was originally discovered by Alessandro Volta in 1794 5 but received no attention at the time. The effect observed by Seebeck was small and little research was performed in the field until the 1950s when improved thermoelectric materials were synthesized from compound semiconductors.…”

“…The effect observed by Seebeck was small and little research was performed in the field until the 1950s when improved thermoelectric materials were synthesized from compound semiconductors. 1 A breakthrough in the thermoelectric field was achieved when the first radioisotope thermoelectric generator was used in the first space mission, Transit IV-A, in 1961. 1 Nevertheless, we are still not seeing thermoelectric technology taking a large role in power generation, even after its successes in remote power generation.…”

“…1 A breakthrough in the thermoelectric field was achieved when the first radioisotope thermoelectric generator was used in the first space mission, Transit IV-A, in 1961. 1 Nevertheless, we are still not seeing thermoelectric technology taking a large role in power generation, even after its successes in remote power generation. This is mainly due to low efficiency and the fact that the best materials are tellurides for low-to mid-range applications and Si-Ge for high temperature applications.…”