| It had been about 200 years, since 1821 Seebeck effect was found by Seebeck. The history of application of thermoelectric effects had been not too long. The technology of thermoelectricity began during the "Great Patriot War" when the Soviet Union, under Academician Ioffe's inspiration, produced thermoelectric generators to be included in a mess kit and capable of powering a small radio from a small cooking fire. Spurred by major advances in semiconductor technology, discovery of more efficient thermoelectric semiconductor alloys, and advances in thermoelectric theory, the 1950s and 1960s witnessed significant efforts to further develop thermoelectric technology. Notable were the radioisotope thermoelectric generators providing critical power for NASA missions on the moon and on Mars and for spectacular successful outer-planetary exploration missions such as Voyagerâ… andâ…¡. Despite successful use of radioisotope thermoelectric generators, basic thermoelectric science continued to decline. Following decades, scientific progress, publications, and meeting activity declined.During the recent decade, activities in thermoelectircs had increased substantially. This was primarily due to three major factors:increasing awareness of the deleterious effect of global warming on the planet's environment, a renewed requirement for long-life electrical power source, including nuclear fueled, and the increasing miniaturization of electronic circuits and sensors. Thermoelectrics was able to make a contribution to meeting the requirements of all three activities.Substantial progress had been made in employing thermoelectrics as an environmentally friendly method of recovering industrial and automobile waste heat, the development of high-performance functionally graded and segmented thermoelements for power source applications, and in the fabrication of reliable thin-film generating, cooling, and sensing devices in the developed countries. China is during its peak period of urbanization now. Substantial development concept had been accepted by more and more people in China. Recovery of waste heat from buildings has been paid more attention now.Thermoelectrics was founded by four basic effects, Seebeck effect, Peltier effect, Thomson effect, and Kelvin effect. Seebeck effect was about energy conversion from heat to electricity. Peltier effect was about energy conversion from electricity to heat. Above four basic effects could be important factors to thermoelectric application. Thermoelectricity was based on the solid carriers and phonon's delivering and interaction. Thermoelectric materials'merit of figure was defined by Seebeck coefficient, thermal conductivity, and electrical conductivity. Clearing the relationship of three coefficients contributed to the high performance thermoelectric materials.Chinese people's living condition have been improved greatly, since China's reforms and opening up from 1978. Domestic air-conditioners have been used in more and more ordinary families now. Power consumption of domestic air-conditioners had been a big burden for power supply, especially in summer and winter. Further more, power consumption of air-conditioner caused by heat load of fresh air supply couldn't be neglected. Especially, it was proved that sufficient fresh air supply could be an efficient method to prevent SARS outbreak.The innovations and originalities of this dissertation had been are included as following:(1) A prototype of thermoelectric ventilator with heat recovery from exhaust of air-conditioned room had been invented successfully. This ventilator could be used to ventilate and improve the thermal comfort of fresh air. Protection of patent for this ventilator had been authorized.(2) As an original invention, all the coefficients of this ventilator had been studied and defined. Volume of ventilation was the basic coefficient for thermoelectric ventilator. Based on occupants' health requirement of fresh air supply, volume of ventilation was defined in some scale. Following government policy of energy saving, final coefficient of volume was followed central authority's energy saving requirement for fresh air supply of air conditioned room.Thermal comfort of fresh air had been paid attention for its effect to occupants. Energy saving and comfort were considered together here. In order to meet these two goals, final thermal comfort coefficient of fresh air had been defined by central authority's energy saving requirement for thermal comfort coefficient of air-conditioned room.As a domestic application, Chinese families'small apartments had been considered also. In order to use this ventilator easily, this ventilator had been designed to be compact enough.Ventilator's fixing and its'inlet and outlet distribution had been all considered in order to realize efficient organized ventilation. (3) A cross flow flat-fin heat exchanger had been originally combined with a thermoelectric heat exchanger as the major function part of this thermoelectric ventilator. Based on the heat transfer theory, two heat exchangers had been studied and their heat transfer models had been constructed respectively.In order to transfer the original concept of this thermoelectric ventilator to be a real prototype, several real ventilator models had been produced to be tested. Ventilator's structure had been optimized through models producing. Optimized performance and structure coefficients of ventilator had been collected through whole test.(4) In order to find the best running coefficient of this prototype, ventilator had been tested its performance in summer and winter, respectively. Through different volumes and thermoelectric power input combined, comparing prototype's heating(cooling) power, coefficient of power, temperature difference of fresh air, optimized running coefficient of this prototype had been set. The test result showed the prototype's coefficient of power could be above 2.5.As an original thermoelectric ventilator with heat recovery, its performance had been compared with traditional ventilator with heat recovery. This ventilator's cost return model had been built and its outlook had been made too. Further improvement of this ventilator had been suggested in this study.(5) A thermoelectric dryer with heat recovery had been studied. Its study had been based on the thermoelectric heat-pump dryer and expanded to focus on heat recovery in order to decrease vapor pollution of dryer exhaust. This thermoelectric dryer with heat recovery had been investigated on three different work modes, opening mode, closed mode, improving closed mode. Through different thermoelectric power input and volume combined, the relationship between dryer's coefficient of power and its running coefficient was found. All three work modes could be used to decrease vapor pollution of dryer exhaust. Opening mode's COP could be advanced traditional dryer 20% to 30%. Under closed mode, vapor pollution of dryer exhaust could be declined to zero with COP value about 1.8. All three work modes'proper application had been suggested in the study. |
PDF Full Text Request