Thermoelectric Source Research Articles

Ultrahigh thermoelectric properties of p‐type BixSb2−xTe3 thin films with exceptional flexibility for wearable energy harvesting

AbstractUse of a flexible thermoelectric source is a feasible approach to realizing self‐powered wearable electronics and the Internet of Things. Inorganic thin films are promising candidates for fabricating flexible power supply, but obtaining high‐thermoelectric‐performance thin films remains a big challenge. In the present work, a p‐type BixSb2−xTe3 thin film is designed with a high figure of merit of 1.11 at 393 K and exceptional flexibility (less than 5% increase in resistance after 1000 cycles of bending at a radius of ∼5 mm). The favorable comprehensive performance of the BixSb2−xTe3 flexible thin film is due to its excellent crystallinity, optimized carrier concentration, and low elastic modulus, which have been verified by experiments and theoretical calculations. Further, a flexible device is fabricated using the prepared p‐type BixSb2−xTe3 and n‐type Ag2Se thin films. Consequently, an outstanding power density of ∼1028 μW cm−2 is achieved at a temperature difference of 25 K. This work extends a novel concept to the fabrication of high‐performance flexible thin films and devices for wearable energy harvesting.

MICROPOWER ENERGY HARVESTING SYSTEMS: OPPORTUNITIES AND CHALLENGES

Most of the review works on micropower energy harvesting systems concentrate on the energy harvesting device (transducer) while its integration with power management and energy storage systems is not further assessed. Therefore, this paper aims to give a complete overview of recent developments in self-sustainable systems concentrating on three fundamental types of ambient energy sources – piezoelectric, radiofrequency and thermoelectric sources. Relevant scientific works are reviewed in terms of transducer type, power management and energy storage in order to evaluate the system’s capabilities to meet the power demand of low power electronic devices such as wireless sensors, wearable electronics, biomedical devices, etc.

Measuring the efficiency gains of merging carbon markets – A microsimulation for thermoelectric and industrial sources

Many carbon markets have emerged worldwide, but their poor sector coverage generates economic inefficiency. This is the first study that quantifies the efficiency gains of expanding the sectoral coverage of an Emissions Trading System (ETS) through an optimization model calibrated with microdata. For the above, the behavior of Chilean thermoelectric and industrial sources that participate in two independent ETSs is simulated, and then the effects of integrating both carbon markets are analyzed. The model minimizes the costs of meeting an aggregate emissions target subject to the abatement options for regulated sources. The results show that if a target of 30 % is established, the price of the allowances would be 36.2 USD/tCO2 in the ETS for thermoelectric sources and 17.4 USD/tCO2 in the ETS for industrial sources. The difference in the prices of both ETSs reflects that their merger would lead to efficiency gains. In fact, the price would be 34.4 USD/tCO2 if both types of sources participate in a single carbon market, implying a saving of USD 30.7 million, equivalent to 9.7 % of the total cost of compliance obtained with independent carbon markets. Thus, it is concluded that expanding the sectoral coverage of an ETS promotes efficiency through lower prices.

Algoritma Differential Evolution untuk Estimasi Parameter Sumber Anomali Self-Potential

Self-Potential (SP) anomaly is naturally occurring potential differences due to electrochemical, electro-kinetic, and thermoelectric sources in the subsurface. The Source of SP anomaly can be modeled as a simple-geometry body, e.g: spheres, cylinders, and inclined sheets. The model parameter of SP anomaly is generally estimated using local optimization such as gradient-search-based methods. However, these methods have some drawbacks. Therefore, this problem needs to address using global optimization, namely Differential Evolution (DE) algorithm. DE is one of the metaheuristic algorithms adopting biological evolution in the optimization process. In this work, the DE algorithm is implemented to estimate the parameters of SP anomaly sources. There are two stages in this work, e.g: synthetic test and field data inversion. In the synthetic test, DE is built and implemented in synthetic data generated from a cylinder body contaminated by noise. This test shows that DE can estimate the parameters of the cylinder body (SP anomaly source) well. In the field data inversion, DE is implemented to estimate the SP Surda anomaly which has been studied by other methods. The results of DE estimation are comparable to the previous studies, and able to provide uncertainty information. DE algorithm can be implemented to characterize the source of SP anomaly for futher study.

Exploring structural, electronic, optical, magnetic, and thermoelectric properties of Pt doped and Pt-Cu/Au co-doped GaN

We present a computational research on investigating the structural, electronic, optical, magnetic, and thermoelectric properties of Pt doped and Pt-Cu/Au co-doped GaN using the Wien2k code. The PBE-GGA approximation is employed in Wien2k code using density functional theory. Study of electronic properties reveals that the d-states of Pt, Cu, and Au atoms participate actively in transferring electron from valence to conduction band and their addition as mono and co-doped formation turns the non-magnetic character of GaN to magnetic. A blueshift in absorption spectrum appear and absorption is more pronounced for Pt-Cu/Au co-doped GaN, suggesting the use of these materials for high energy UV optoelectronics, spintronics, photonic, and sensing devices. However, lower reflection and enhanced conductivity of Pt-Cu/Au co-doped materials in the UV region extends their potential applications in high frequency electronics. Moreover, higher ZT value of Pt@GaN suggest it a better thermoelectric source other than Pt-Cu/Au@GaN.

Electric energy planning in Namibe, Angola: Inserting renewable energies in search of a sustainable energy mix

The socioeconomic development of any region requires electricity for operating the various sectors of the economy. Sometimes energy is scarce, not only because of the lack of energy resources, but also because energy policy is inadequate or non-existent. This paper examines the situation in the province of Namibe, Angola, characterising the energy sector, and proposing an energy mix for the security of electricity supply, environmental protection and sustainable economic development. Using the Long-range Energy Alternative and Planning System, energy scenarios were simulated and the greenhouse gas emissions (GHGs) for the period 2014-2040 calculated and analysed. The most sustainable scenario, in terms of energy mix diversification and GHG reduction, as well as the least costly (considering electricity production and carbon costs), has an increase of hydro capacity and the insertion of wind, solar photovoltaic, thermoelectric sources and natural gas. Given the intermittency of photovoltaic and wind systems, natural gas appears in this scenario as a way to avoid interruptions in the electricity supply. This scenario is the one with the largest production reserve margin of 24.47 %, and emissions are avoided at 386 550 tCO2eq compared to the base scenario in 2040. Energy policymakers can take this scenario as a model to assist in making decisions on how power capacities can be installed over the planned time for the desired energy output.

Version of a mathematical model of purge ventilation system with a complex recuperative heat exchanger

The aim of the study is to develop a design of an air-heating recuperator for a purge ventilation system of a building inbuilt for the purpose of utilizing lower-grade heat from ventilation gases and emissions with the associated production of thermoelectricity. An experimental design of an air-heating recuperator as part of an experimental purge unit has been developed. It includes a thermoelectric source of electromotive difference, which operates as a result of the associated conversion of heat into electricity, which allows utilizing lower-potential heat of ventilation releases from 40°C to 60°C.

Backup thermoelectric sources of electric energy

The article presents the rationale for the use of thermoelectric systems to provide backup power supply for actuators and automation systems for engineering systems of multistory buildings. The experiments were carried out using the developed stand, which modulated the parameters of the engineering systems of multi-storey buildings. The stand consists of a NEPS-100-220-0.03-UHL4 heating element and a CoolerMasterI30 cooler, the temperature on the sides of the thermoelectric module is controlled by a TPM-2 thermostat using a solid-state relay, the thermoelectric power value is recorded by an OVEN IMS device. F1, the electrical load is set by the resistance bridge. Temperature control of thermoelectric elements, hot and cold sides of a thermoelectric module, as well as sources of “heat” and “cold” is carried out by thermocouples, the data is recorded by the TPM138 meter-regulator. As a result of the work carried out, it was found that with the help of new technical solutions it is possible to increase the temperature on the heat exchange sides of thermoelectric modules and bring their technical parameters to the area of maximum efficiency. When organizing thermoelectric systems, it will be possible to provide backup power to the equipment used in heat points of multi-storey buildings.

Design and implementation of a current controlled grid connected inverter for thermoelectric generator sources

This paper presents the digital implementation of a current controlled grid connected inverter for Thermoelectric Generator (TEG) sources. Considering the electrical characteristics of a TEG source, several important aspects that a designer has to consider in selecting the rating of power converters for the grid connected operation of TEG source are discussed. The closed loop control of a TEG fed grid connected voltage source inverter (VSI) requires line current control to regulate the power pumped into the grid. Considering the inverter, current sensor and line inductor models, a simplified method is espoused to determine the parameters of the digital current controller. An Altera Cyclone II FPGA board is used to implement the current control strategy in VSI fed with TEG power source. The proposed design approach is validated using simulations and experiments and verified with the time domain specifications.

Effectiveness of local air pollution and GHG taxes: The case of Chilean industrial sources

In 2017, environmental taxes began to be applied to CO2, PM, NOx and SO2 emissions in Chile to reduce the negative environmental effects of fossil fuels burned in industrial and thermoelectric sources with a thermal power greater than or equal to 50 MW. In this context, the present study generates an economic optimization model to simulate how different tax scenarios would modify the behavior of regulated industrial sources considering the alternatives they have to minimize their costs (tax payment, fuel change and/or installation of abatement technologies). The main results show that, under the current tax scenario, CO2, PM and SO2 emissions would decrease by 11%, 48% and 49% respectively, while NOX emissions would increase by 5%. By extending the tax to all industrial sources regardless of their thermal power, CO2, PM and SO2 emissions would decrease respectively by 14%, 98% and 66%, while NOX emissions would increase by 7.1%. Finally, it is determined that modifying the tax rate of a single pollutant while maintaining the rest of the constant rates generates a low impact on the other pollutants emissions.

Research of Thermocouple Electrical Characteristics

This paper presents the results of the experimental research on the electrical characteristics of two dissimilar thermoelectric power sources. Chromel-alumel and nichrome-constantan are the investigated types of thermocouples that are utilized as thermopower sources. Through the assistance of the collected data, experimental and theoretical studies of two equivalent thermopower sources are done. The first studied source is obtained by a parallel connection of the two types of thermocouples, and the second studied source is achieved by the parallel connection of two thermocouples of nichrome-constantan and a single thermocouple made of chromel-alumel. Theoretical studies of the two equivalent thermoelectric sources proved good repeatable precision of the studied results of experimental measurements.

Bootstrapping and Resetting CMOS Starter for Thermoelectric and Photovoltaic Chargers

Sustaining microsensors for years is challenging because tiny batteries exhaust quickly, and recharging or replacing thousands of networked nodes is impracticable. Harnessing heat or light energy helps, but only when available. And even then, tiny generators output less than 300 mV, which is not enough to operate microelectronics well. This brief presents a 0.18- $\mu$ m CMOS starter that charges a temporary 1.8-V supply quickly and reliably from slow- or fast-rising photovoltaic and thermoelectric sources. For this, a jump starter helps an LC tank oscillate to a level that allows a discharge path to output power. A resetter then continually resets the circuit until the system senses the temporary supply is ready. This way, with 1.8 V, a charging system can then charge a battery quickly before the onset of another harvesting drought. The starter does not require off-chip components because it borrows the switched inductor that the charging system already uses to charge the battery. A prototype of the starter proposed charges 120 pF to 1.8 V in 15–59 $\mu$ s with 1.5%–7% efficiency from a 180 $\Omega$ , 220–250-mV source.

Modelling Kerf Width in WEDM Titanium Alloy Using Response Surface Methodology

Wire electrical discharge machining is a material removal process of electrically conductive materials by the thermo-electric source of energy. This kind of machining extensively used in machining of materials with highly precision productivity. This work presents the machining of titanium alloy (TI-6AL-4V) using wire electro-discharge machining with brass wire diameter 0.5mm.The objective of this work is to study the influence of three machining parameters namely peak current, pulse off time and wire tension to kerf width followed by suggesting the best operating parameters towards good machining characteristics. A full factorial experimental design was used with variation of peak current, feed rate and wire tension, with results evaluated using analysis of variance techniques (ANOVA). The test array was further extended to allow for the implementation of Response Surface Methodology (RSM) analysis in order to develop first and second order models for the prediction of kerf width response. The results showed that average percentage error between the predicted and experimental value for kerf width models was less than 2%.

High Power Interdigitated Carbon Nanotube Based Micro-Capacitors

ABSTRACTMicro-scale energy storage devices are of great importance to the advancement of low maintenance, high power electronics. They can easily be used in applications that extract energy from mechanical, solar, thermal and thermoelectric sources. Several of these devices have achieved mean areal capacitance of 1.5 mF cm-2 and maximal energy and power densities of 6.6 mJ cm-2 and 44.9 mW cm-2, respectively. It has been demonstrated that a smaller interspace enhances the performance. Currently, these types of devices are only made possible by using several micro-fabrication steps and techniques that are cost prohibitive and limit the larger scale manufacturability. We present a simple but highly scalable and cost effective method in fabricating high power interdigitated micro energy storage devices using binder-free carbon nanotubes membranes and laser irradiation to obtain interspaces on the order of 75 μm. The binder-free electrode devices show higher power density and an improved frequency response, compared to what has been reported in the literature. Additionally, we observed significant reduction in cell resistance leading to enhancement in cell capacitance, and consequently, an increase in energy density.

A High-Efficiency Energy Harvesting Interface for Implanted Biofuel Cell and Thermal Harvesters

A dual-source energy harvesting interface that combines energy from implanted glucose biofuel cell and thermoelectric generator is presented. A single-inductor dual-input dual-output boost converter topology is employed to efficiently transfer the extracted power to the output. A dual-input feature enables the simultaneous maximum power extraction from two harvesters, whereas a dual output allows a control circuit to perform complex digital functions at nW power levels. The control circuit reconfigures the converter to improve the efficiency and achieve zero-current and zero-voltage switching. The measurement results of the proposed boost converter, implemented in a 0.18 ${\mu }$ m CMOS process, show a peak efficiency of 89.5% when both sources provide a combined input power of 66 ${\mu }$ W. In the single-source mode, the converter achieves a peak efficiency of 85.2% at 23 ${\mu }$ W for the thermoelectric source and 90.4% at 29 ${\mu }$ W for the glucose biofuel cell. The converter can operate from minimum input voltages of 10 mV for the thermoelectric source and 30 mV for the glucose biofuel cell.

Characteristics of Machining Parameters on WEDM Titanium Alloy

Wire electrical discharge machining is a material removal process of electrically conductive materials by the thermo-electric source of energy. This kind of machining extensively used in machining of materials with highly precision productivity. This work presents the machining of titanium alloy (TI-6AL-4V) using wire electro-discharge machining with brass wire diameter 0.5mm.The objective of this work is to study the influence of three machining parameters namely peak current, pulse off time and wire tension to cutting rate, material removal rate, surface roughness and kerf width followed by suggesting the best operating parameters towards good machining characteristics. A full factorial experimental design was used with variation of peak current, feed rate and wire tension, with results evaluated using analysis of variance techniques. Parameter levels were chosen based on best practice and results from preliminary testing. Main effects plots and percentage contribution ratios are included for the main factors and their interactions.

Analysis of Power Processing Architectures for Thermoelectric Energy Harvesting

This paper analyzes, from a power processing architecture standpoint, the recovery of thermal energy waste by means of thermoelectric (TE) modules and arrays. The existence, in many industrial scenarios, of stable and often significant temperature gradients enables a number of possibilities for effective processing and recovery of waste heat, which could result in marked economic savings and environmental benefits if adopted on a large scale and systematically embedded into industrial processes. A review of the TE source is provided first, along with an extensive experimental characterization of commercial bismuth-telluride TE cells. Results indicate that maximum power extraction from TE generators can be achieved at a TE efficiency close to optimal, motivating the adoption of maximum power point tracking architectures, traditionally employed in photovoltaic systems, to TE plants as well. Three power processing architectures are then analyzed and compared in terms of their maximum power extraction capabilities and of the efficiency constraint they pose on the power processors. Different from the photovoltaic case, the simple series configuration of TE modules allows to extract most of the available power even in the presence of rather large mismatches among the modules. For even larger mismatch levels, the differential power processing (DPP) concept, already introduced for dc–dc distribution systems and photovoltaic plants, can be successfully adopted to improve power extraction. On the other hand, the module-integrated converter architecture, another well-established solution for photovoltaic sources, is found to be much less indicated for TE generators than the DPP solution. Main conclusions are experimentally validated using a DPP architecture with a two-cell test bed operated at different thermal gradients.

A review on the potential sources for producing electricity with thermoelectric generators and different configurations

Thermoelectric source has proven its efficaciousness as a clean and affordable alternative energy source. Thermoelectric generators are the ones which can produce electricity from heat. The concept of thermoelectricity, its production and its related concepts are reviewed in this paper. Peltier tile, a device used as a TEG, is used in various ways to produce electricity which are thoroughly reviewed in this paper. Thermoelectricity produces from these tiles proves to be a very good source of alternate energy. Despite technological revolutions, there are many places devoid of electricity due to various reasons. Thermoelectricity generation would prove to be a very clean and affordable alternative energy source in these areas. This paper reviews TEG how it generates a clean, affordable and easily accessible energy: electricity, without the need of transmission lines.

A Compact Multi-Input Power Conversion System with High Time-Efficiency Inductor–Sharing Technique for Thermoelectric Energy Harvesting Applications

A compact multi-input thermoelectric energy harvesting system implemented in a 0.18[Formula: see text][Formula: see text]m CMOS technology is proposed to extract electrical energy from human body heat. By combining the techniques on inductor sharing and bidirectional power converter, the harvesting- and regulating-stage circuits in conventional energy harvesting system can be merged into a single-stage circuit. With the proposed duty-cycle-based strategy for maximum power extraction and the high-efficiency timing scheme for inductor sharing, the proposed multi-input thermoelectric energy harvesting system can ensure optimal power transfer from each thermoelectric energy source without sacrificing power conversion efficiency (PCE) and maximum output power capability. The peak PCE is achieved at 58.5%, the maximum end-to-end output power is 2.43[Formula: see text]mW, and the maximum output power capability is 32.4[Formula: see text]mW while the storage capacitor is fully charged.

Implementation and Analysis of Electricity Generation by Thermoelectric

This paper presents an implementation and analysis of producing electricity by thermoelectric principle. The paper describes an experimental thermoelectric prototype to investigate the electric generation. Firstly, the appropriated design of the thermoelectric unit is constructed as a laboratory prototype to measure performance of the electricity generated under the condition of on-load and no-load. All parameters are recorded such as voltage (V), current (A), and both sides temperature range (ΔT). Secondly, the power output of the prototype is analyzed. The experimental, results shows that while no-load temperature range (ΔT) from 0 – 110°C, the output voltage (V) was up to 1.17 V at 110 °C and with 2 Ω-loads the output current (I), voltage (V), and power (W) were 212.6 mA, 0.850 V and 180.71 mW respectively. For 10 thermoelectric source connected in series, while no-load and 2 Ω-loads, the output voltage (V) was at maximum of 13.57 V and minimum of 1.213 V at 110 °C. This can be seen that the voltage output from the power output is fluctuated. Therefore a proper design of buck-boost converter is necessary to stabilize the output voltage for purpose of charging battery application.