Vol.1 No.2 2008

16/85

Research paper−85 Synthesiology - English edition Vol.1 No.2 (2008) Thermoelectric power generation is drawing attention as the best candidate for technology that allows conversion of waste heat into electric power. This is because, since there is no scale effect in thermoelectric conversion, however small the heat energy, electric energy equal to the thermoelectric conversion efficiency spent on the heat energy can be obtained. For example, it is calculated that if 20 % of waste heat disposed from automobiles, plants, garbage incineration plants, and others could be converted to electricity, we can obtain 35 thousand GWh of power a year[2]. This figure is equivalent to power produced by a medium-size nuclear power plant. Also, thermoelectric generation system does not produce CO2 or radioactive material, has no moving parts such as a turbine, and is a clean, maintenance-free, and long-lasting energy conversion system.Thermoelectric power generation has been studied for quite a long time, and there were great expectations each time new materials were discovered followed by great disappointments. Therefore, users often regarded thermoelectrics with cold eyes: “Oh, thermoelectric again….” This was because even if a material had excellent properties, when putting it to civilian use, it often ran into major problems of safety, durability, cost, or of manufacturing technology. Also, in the United States, 10 years ago, civilian use of thermoelectric power did not arouse enthusiasm due to the attitude, “Gasoline is cheap so we don’t need thermoelectric power” , thus retarding its civilian use. However, expectation for thermoelectric power is rising again because of the shift in consciousness for energy and environment issues. It is rising from the demand from users rather than researchers of thermoelectric materials. One of the triggers of such movements was the discovery of excellent thermoelectric oxides by Japanese researchers including the Authors.1 Background of researchThe production of fossil fuel, our mainstay of energy, is expected to reach its peak in a few years, and humankind is faced with challenges to find early solutions for stable supply of energy and environmental problems. Therefore, many research institutes are actively tackling R&D of new heat and energy conservation technologies. One of the solutions to these serious issues is efficient use of waste heat that is unused and disposed of into the atmosphere. Japan consumes and imports several hundred million kiloliters of primary energy in crude oil equivalent every year. However, about 70 % are disposed into the atmosphere as heat energy (Figure 1)[1]. Using this unused waste heat and improving energy efficiency are extremely important issues along with the development of alternative energy to oil.Even though the total quantity of waste heat is massive, there is actually little energy disposed by a single heat engine. Waste heat energy is dispersed widely and thinly. - Recovery system of high-temperature waste heat by new thermoelectric oxides -Ryoji Funahashi* and Saori Urata***Nanotechnology Research Institute, AIST Midorigaoka 1-8-31, Ikeda, Osaka 563-8577, Japan **Japan Science and Technology Agency Honcho 4-1-8, Kawaguchi 332-0012, Japan *E-mail : As energy and environment issues become serious, there is an urgent need to improve efficiency of industrial energy use as well as to alter lifestyles. To realize thermoelectric conversion technology that allows power generation from waste heat, we newly discovered thermoelectric oxides that possess high safety and durability at high temperatures. We then developed a prototype of a small-size generation system that functions at temperature range of 773~1173K in collaboration with a private companyDevelopment of a small-size cogeneration system using thermoelectric power generationKeywords : Thermoelectric power generation, oxides, moduleFig. 1 Huge amount of waste heat.In Japan, about 70 % of all primary energy supply is unused and disposed into the atmosphere as waste heat.[Translation from Synthesiology, Vol.1, No.2, p.94-100 (2008)]All primary energy supplyAll primary energy supplyThermal power plantNuclear power plantAutomobileIncineration plantplantNatural gas (cold thermal)Loss/waste heat energyUsed energy(13)−

※このページを正しく表示するにはFlashPlayer9以上が必要です