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[en] Highlights: ► A new TEG test measurement system with the PLC has been carried out. ► A new SCADA program has been written and tested for the test measurement system. ► An operator panel has been used for monitoring to the instant TEG data. ► All of the measurement data of TEG have been aggregated in the system. - Abstract: In this study, a new test measurement system and supervisory control and data acquisition application with programmable logic controller has been carried out to be enable the collection of the data of thermoelectric generator for the usage of thermoelectric modules as thermoelectric generator. During the production of the electric energy from the thermoelectric generator, the temperatures of the surfaces of the thermoelectric generator, current–voltage values obtained from output of the thermoelectric generator, hot and cold flows have been measured by the newly established system instantly. All these data have been monitored continuously from the computer and recorded by a supervisory control and data acquisition program. At the same time, in environments where there was no computer, an operator panel with the ability to communicate with the programmable logic controller has been added for the monitoring of the instant thermoelectric generator data. All of the measurement data of the thermoelectric generator have been aggregated in the new test measurement and supervisory control and data acquisition system. The setup test measurement system has been implemented on the thermoelectric generator system with about 10 W. Thermoelectric generators, Altec-GM-1 brand-coded have been examined by the new proposed test measurement system and the values of maximum power and thermoelectric generator efficiency were calculated by the programmable logic controller. When the obtained results were compared with the datasheets, the relative error for the maximum power was around 4% and the value for efficiency was below 3%.
[en] The Seebeck and Peltier effects are explored with a commercially available thermoelectric module and a data-acquisition system. Five topics are presented: (i) thermoelectric heating and cooling, (ii) the Seebeck coefficient, (iii) efficiency of a thermoelectric generator, (iv) the maximum temperature difference provided by a thermoelectric cooler and (v) the Peltier coefficient and the coefficient of performance. Using a data-acquisition system, the measurements are carried out in a reasonably short time. It is shown how to deduce quantities important for the theory and applications of thermoelectric devices
[en] Highlights: • Nominal power density of TEGs with non-constant cross sections pins is analyzed. • An analytical model of nominal power density (NPD) is developed. • Influences of shape parameter on NPD for different geometric pins are investigated. • Effects of dimensionless efficiency and the temperature ratio on NPD are examined. - Abstract: The investigation of the geometric structure of TEG (thermoelectric generator) pins is essential, as their geometry determines the performance of devices. In this study, nominal power density (NPD) is used to find a better geometric structure of thermoelectric pins of TEGs, since a comparison of maximum dimensionless efficiencies for different geometric pins cannot be used to identify the optimum geometry. The influence of shape parameter on NPD for TEG pins in linear, quadratic and exponential cross-sectional functions is studied. The NPD decreases when the shape parameter increases for different geometric pins, while the maximum values of NPD are the same. Then, the effects of dimensionless efficiency and the temperature ratio on the NPD are analyzed. The NPD decreases with the increase in dimensionless efficiency and temperature ratio. Pins with linear variation in cross section have the highest NPD among the three geometries of pins evaluated
[en] Highlights: ► Thermodynamic analysis of thermoelectric power generator is carried out. ► The influence of the slope parameter on the efficiency is formulated. ► The efficiency of thermoelectric generator is influenced by the slope parameter. ► The power generation by the device reduces with slope parameter. ► Increasing external load resistance decreases the efficiency. - Abstract: Thermoelectric power generators are one of the promising clean energy resources with the cost effective operation despite the low device efficiency. Investigation into device efficiency improvement is necessary for the practical applications. Consequently, in the present study, a theoretical analysis of thermoelectric power generator is carried out and influence of thermoelectric leg geometry on the device efficiency and the power generation is formulated. The geometric configuration of the legs in the device is associated with the shape parameter and incorporated in the analysis. The influence of the shape parameter on the device efficiency and power generation is examined for various temperature and external load resistance ratios. It is found that increasing or decreasing of the shape parameter (μ) has a favorable effect on the device efficiency; however, the shape parameter (μ) has an adverse effect on the thermoelectric power generation.
[en] Highlights: • We analyze the practical performance of TEMs to meet specific requirements. • The influence of different input power sources are discussed. • The step-change phenomena of thermoelectric cooling are found and discussed. • The influence ratio of hot side heat exchanger and input power source is compared. - Abstract: The practical operating conditions of thermoelectric products, such as the input power source and the thermal resistance of hot side heat exchanger, are different from the theoretical study. Thus the equations, which are used to estimate the practical maximum cooling performance just according to the datum in datasheet of commercial thermoelectric module (TEM), are given. The nested loop method is adopted to solve the numerical model. This study provides a method to choose a suitable TEM for thermoelectric product to meet the application requirement. It finds that the minimum cold side temperature increase and the voltage for achieving the minimum cold side temperature step decrease with the increase of thermal resistance of hot side heat exchanger, respectively. The maximum temperature difference increase and the voltage for achieving the maximum temperature difference step increase with the increase of thermal resistance of hot side heat exchanger, respectively. According to the dimension, three kinds of thermoelectric module, bulk TEM, miniature TEM and micro TEM, are studied. The novel scale effect are discovered by comparing these TEMs. It found that the step-change phenomenon become more and more obvious with the decrease of the dimension of thermoelectric module. The influence ratio of thermal resistance of hot side heat exchanger on the maximum cooling performance increases and the influence ratio of input power source decreases from macro to micro, respectively. It forecasts that there exists a critical value for the dimension of thermoelectric module, when the dimension of thermoelectric module is smaller than this critical value, the maximum voltage or current of thermoelectric module is constant and does not change with the thermal resistance of hot side heat exchanger
[en] A simple model has been presented for the conduction of current between adjacent electrodes separated by an insulating wall and duct filled with conducting hot gases. Analytical expressions and calculations have been made for plasma initiated and insulator initiated breakdowns for the conditions prevailing in a typical open cycle MHD generator. The relative importance of the two types of breakdowns has also been evaluated. (author)