Papers by Keyword: Thermoelectric Effect

Abstract: The thermoelectric effects in oxide materials are developed to the Seebeck effect for thermal sensing. Thermal sensors are the thermal converters, in which an electrical, magnetic, mechanical, radiation, chemical signal are measured by converting it into heat and measuring the resulting temperature changes in the device. This proposes an analysis the electrical converters and radiation sensors by using single−junction of p−Ca₃Co₄O₉ and n−CaMnO₃ materials are presented into possible thermal sensing. Several thermal converters are measured the signal electrical resistivity, and Seebeck coefficient depended on temperature. Thermal radiation sensors are included the sensitivity, electricity, and specific detectivity. For application, thermoelectric oxide cell can be fabricated crowbar circuit for protection an overvoltage condition of a power supply which it yield 1.2 s turn off switch.

Abstract: Semiconductor thermoelectric generators have a series of advantages, such as compact volume, high-level reliability, and effective power generation in the presence of temperature difference. In many occasions, as a result of high voltage, electrical equipments can't be measured by the way of direct contact. In order to avoid equipment faults caused by low-voltage contact, a thermoelectric generator which uses waste heat of electrical equipments in service was designed. Electrical equipments often operate below 400K, and in this condition Bi₂Te₃ shows an outstanding performance of power generation. In order to solve the problems of little temperature difference and output power on steady-state, two methods were introduced. On the one hand, the temperature difference can be increased by filling with thermal insulation padding between the p-n junctions and using a heat sink in the cold side, and on the other hand, the output voltage and power will be augmented by increasing the number of p-n junctions. These methods have been proved effectively by simulation and experiment with promising outcomes.

Abstract: A novel self-powered device based on the aligned carbon nanotube arrays (CNTA) in multi-physics fields has been put forward in this paper. Synthetically utilizing the photic, fluidic and thermic properties of carbon nanotubes, the multi-physical nanogenerators (MPNG) can generate electric currents when the solar irradiation and air flow synchronously effect on the material surface. Various MPNGs are connected in series to construct a unique truncated conus and cylinder shell structure in order to enhance the output voltage for self-powered electronic devices. The multi-physical power mechanism is formed by converting the solar and air flow energy to the thermoelectric effect. By the finite element analysis, the MPNG model including a pair of p-type and n-type CNTA elements is established, and its temperature and potential distribution are simulated. This self-powered device in multi-physics fields can be applied to a more complicated environment and has a fine prospect.

Abstract: In recent years, Building Integrated Photovoltaic (BIPV) system has been becoming one of most important application of solar energy. Heat is the key of the BIPV design. If the temperature of photovoltaic modules is too high, it will affect the efficiency of solar cells, the structure performance of the components and service life. This paper present a photoelectric-thermoelectric (PV-TV) model which can collect heat from the solar panels so that to reduce its surface temperature, and then to generate electricity by using of temperature difference technology and devices. The model presented in this paper provides designers a new concept in BIPV design.

Abstract: The purpose of this study is to develop an in-process of measurement technique of surface roughness using thermoelectric effect in cylindrical grinding. The electromotive force (EMF) generates depend on the surface roughness of workpiece and the variation of workpiece temperature when the sensor with thermocouple wires rubs on the workpiece surface in grinding process. In this paper, the in-process measurement technique of surface roughness in cylindrical plunge grinding is proposed, conceiving the cancellation of the EMF caused by the variation of workpiece temperature in the sensor output. Also a new type in-process sensor was developed for high accuracy to overcome the problem which was clarified in the cancellation method of the influence of workpiece temperature at a basic sensor.

Abstract: A Bi2-xSbxTe3(x=0-1.5) thick film thermoelectric element was fabricated using centrifugal deposition and its Sb content-dependent thermoelectric properties were investigated. When the Sb content was low (x=0.5), two types of fine structure along the direction of the thickness were observed. Pole figure measurements revealed that the vicinity of the film surface was composed of single crystal layers oriented along the c-axis and the vicinity of the interface with the substrate was composed of randomly orientated layers. As the content of Sb increased, the degree of orientation improved, and at x=1.5 the entire film was close to a single crystal. A Bi0.5Sb1.5Te3 thick film showed p-type thermoelectric properties and a thermoelectric power factor of 3.5 ×10-3W/mK2. It was thus demonstrated that centrifugal deposition can be used to fabricate thermoelectric elements with high efficiency.