Thermoelectric Conversion Devices Research Articles

"Machine learning assisted understanding of the layer-thickness dependent thermal conductivity in fluorinated graphene".

Manipulating thermal conductivity (k) plays vital role in high-performance thermoelectric conversion, thermal insulation and thermal management devices. In this work, we using the machine learning-based interatomic potential and the phonon Boltzmann transport equation to systematically investigate layer thickness dependent thermal conductivity of fluorinated graphene (FG). We show that the lattice of FG can be significantly decreased with Bernal bilayer stacking. Surprisingly, the further increasing of stacking layer can no longer affect the thermal conductivity, however, the is increased in the bulk configuration. The variation of thermal conductivity can be attributed to the crystal symmetry change from P-3m1 (164) at single layer to P3m1 (156) at multilayer. The decreasing crystal symmetry from single layer to bilayer resulting stronger phonon scattering and thus leading a lower thermal conductivity. Moreover, we also show that the contribution of acoustic mode to κ decreases with the increase of layers, while the contribution of optical mode to κ is increased with increasing layers. These results provide a further understanding for the phonon scattering mechanism of layer thickness dependent thermal conductivity.

Low-grade heat recycling of vertical thermoelectric cells based on thermal-induced electric double layer

Employing electric double-layer (EDL) capacitors to harvest low-grade heat (LGH) is a novel technique in the high-efficiency energy absorption field. This work reports the fabrication of a vertical thermoelectric cell, based on a nanoporous graphene electrode immersed in low-concentration saline solution, for use as thermo-charging supercapacitors to convert LGH to electricity via thermally induced voltage. Because of a large specific area and a large number of micropores of nanoporous graphene films, the effective thermoelectric coefficient of the thermoelectric cell containing 0.01 M KCl solution can reach as high as 4.73 mV/°C. However, many factors, such as electrode materials, electrolyte solutions, and energy conversion device components, determine the efficiency of a thermoelectric conversion device. In summary, the device has a lower internal resistance and higher output voltage when the concentration of KCl solution is 0.05 M, and demonstrates higher thermoelectric conversion efficiency. Moreover, improving the conductivity of the electrolyte solution without affecting the device output voltage is also a way to reduce the internal power consumption of the device. The specific power and thermoelectric conversion efficiency of the device are increased by several orders of magnitude when uniformly dispersed silver nanoparticles are added to the potassium chloride solution to enhance the conductivity of the solution. The specific power underwent an increase from 0.50 mW g−1 to 42.37 mW g−1, and the thermoelectric conversion efficiency also increased from 0.0022% to 0.1358%.

Precipitation enhancement of liquid thermoelectric conversion with Fe(ClO4)2/Fe(ClO4)3 dissolved in DMF

Oxidant precipitation in the electrolyte significantly enhances the open circuit voltage and output power in a liquid thermoelectric conversion device.

Concentration gradient effect in liquid thermoelectric device composed of organic-solvent-added aqueous solution containing K4[Fe(CN)6]/K3[Fe(CN)6

A liquid thermoelectric conversion device (LTE), which has a simple device structure composed of low-cost materials, is attracting attention. Here, we investigated the additive effect of methanol (MeOH), acetone, and tetrahydrofuran (THF) on an LTE composed of a K4[Fe(CN)6]/K3[Fe(CN)6] aqueous solution. We ascribed to the enhancement of the thermal voltage V and electrochemical Seebeck coefficient α to precipitation of K4[Fe(CN)6] and resultant concentration gradient of [Fe(CN)6]3− between the hot and cold electrodes. The enhancement of V and α is quantitatively reproduced by the concentration gradient model incorporating experimentally-obtained solubility s(T) of K4[Fe(CN)6]. We further demonstrated that precipitation enhances the maximum power by as much as 152% in a MeOH-added LTE composed of 0.35 M K4[Fe(CN)6]/K3[Fe(CN)6] aqueous solution at ΔT = 10 K.

Concentration dependence of resistance components in solutions containing dissolved Fe2+/Fe3.

Electrolyte solutions containing Fe2+/Fe3+ are suitable for liquid thermoelectric conversion devices (LTEs), because they are inexpensive materials and exhibit a high electrochemical Seebeck coefficient α. Here, we investigated the concentration (c) dependence of resistance components, i.e., solvent (Rs), charge-transfer (Rct), and diffusion (Rdif) resistances, of dissolved-Fe2+/Fe3+-containing aqueous, methanol (MeOH), acetone, and propylene carbonate (PC) solutions. We found that the c dependence of Rs and Rdif are well reproduced by empirical formulas, and , where η(c) is viscosity at c. We further found that the magnitudes of Cs and Cdif are nearly independent of solvent, suggesting that η is one of the significant solution parameters that determine Rs and Rdif.

Study on heat transfer coupling mechanism of direct thermoelectric conversion with regenerative cooling for supersonic combustor applications

Direct thermoelectric conversion is a promising technology that converts aerodynamic and combustion heat into electric energy for thermal management of supersonic combustors. However, the heat transfer process of direct thermoelectric conversion coupled with regenerative cooling of supersonic combustors is rarely studied and the coupling mechanism is not clear. In this paper, a novel “SANDWICH” thermoelectric/cooling integrated model (TCIM) proposed by the present work based on Skutterudite (SKD) or Half-Heusler (HH) thermoelectric conversion devices is analytically studied. The energy conversion and heat transfer mechanism of the direct thermoelectric conversion coupled with regenerative cooling are revealed. Using the analytical model, the effects of structural parameters of thermoelectric conversion device and the heat transfer coefficient of regenerative cooling on the energy conversion efficiency and output power are investigated for two typical thermal conditions corresponding to the isolation part and the combustion part of a Mach 2.5 supersonic combustor. The analytical results showed that larger size of the thermoelectric conversion device can effectively improve the conversion efficiency and output power per unit area. Increasing the heat transfer coefficient of regenerative cooling can lower the structural temperature and increase the output power per unit area by more than 12%. Furthermore, with a multi-parameter optimization method based on Genetic Algorithm, optimization for the output power per unit area is conducted with variations of the structural parameters of TCIM under constraints of the tolerance temperature and the types of thermoelectric conversion devices. A more than 10% increase in the output power per unit area for both SKD and HH TCIMs are achieved via the optimization.

Autonomously Tuning Multilayer Thermal Cloak with Variable Thermal Conductivity Based on Thermal Triggered Dual Phase-Transition Metamaterial

Thermal cloaks offer the potential to conceal internal objects from detection or to prevent thermal shock by controlling external heat flow. However, most conventional natural materials lack the desired flexibility and versatility required for on-demand thermal manipulation. We propose a solution in the form of homogeneous multilayer thermodynamic cloaks. Through an ingenious design, these cloaks achieve exceptional and extreme parameters, enabling the distribution of multiple materials in space. We first investigate the effects of important design parameters on the thermal shielding effectiveness of conventional thermal cloaks. Subsequently, we introduce an autonomous tuning function for the thermodynamic cloak, accomplished by leveraging two phase transition materials as thermal conductive layers. Remarkably, this tuning function does not require any energy input. Finite element analysis results demonstrate a significant reduction in the temperature gradient inside the thermal cloak compared to the surrounding background. This reduction indicates the cloak’s remarkable ability to manipulate the spatial thermal field. Furthermore, the utilization of materials undergoing phase transition leads to an increase in thermal conductivity, enabling the cloak to achieve the opposite variation of the temperature field between the object region and the background. This means that, while the temperature gradient within the cloak decreases, the temperature gradient in the background increases. This work addresses a compelling and crucial challenge in the realm of thermal metamaterials, i.e., autonomous tuning of the thermal field without energy input. Such an achievement is currently unattainable with existing natural materials. This study establishes the groundwork for the application of thermal metamaterials in thermodynamic cloaks, with potential extensions into thermal energy harvesting, thermal camouflage, and thermoelectric conversion devices. By harnessing phonons, our findings provide an unprecedented and practical approach to flexibly implementing thermal cloaks and manipulating heat flow.

Sustainable utilisation and transformation of the thermal energy from coalfield fires: A comprehensive review

Coalfield fires provide high-temperature heat storage at relatively shallow depths, their overburden and upper strata contain immense amounts of thermal energy, which is identical to the reservoir condition of shallow geothermal energy. Therefore, heat waste resources produced by coalfield fires can be developed and utilised as low-medium grade geothermal resources. By comparing the available methods for thermal energy extraction and conversion, it was found that the heat transfer technology using two-phase closed thermosyphon and thermoelectric conversion using thermoelectric conversion device were the most suitable for use in coalfield fire areas. As a highly effective heat conduction scheme, the two-phase closed thermosyphon was proposed as a feasible means of thermal energy extraction. Meanwhile, thermoelectric conversion device was utilised to transform thermal energy directly into electrical energy to realise the reuse of the waste heat. Some influencing factors on the heat transfer properties of two-phase closed thermosyphon were analysed, and efficiency of the thermoelectric conversion device was investigated. The thermoelectric parameters for these thermoelectric materials of interest were evaluated, and several effective methods for the improvement of thermoelectric conversion efficiency were exposed. In addition, an enhanced thermoelectric conversion and utilisation system with increased conversion efficiency was proposed. The results presented in the current study can provide a theoretical basis and technical support information for the feasible management and adequate control of coalfield fires and utilisation of the resulting thermal energy.

Ultralow lattice thermal conductivities and excellent thermoelectric properties of hypervalent triiodides XI3 (X = Rb, Cs) discovered by machine learning method.

Thermal conductivity and power factor are key factors in evaluating heat transfer performance and designing thermoelectric conversion devices. To search for materials with ultralow thermal conductivity and a high power factor, we proposed a set of universal statistical interaction descriptors (SIDs) and developed accurate machine learning models for the prediction of thermoelectric properties. For lattice thermal conductivity prediction, the SID-based model achieved the state-of-the-art results with an average absolute error of 1.76W m-1 K-1. The well-performing models predicted that hypervalent triiodides XI3 (X = Rb, Cs) have ultralow thermal conductivities and high power factors. Combining first-principles calculations, the self-consistent phonon theory, and the Boltzmann transport equation, we obtained the anharmonic lattice thermal conductivities of 0.10 and 0.13W m-1 K-1 for CsI3 and RbI3 in the c-axis direction at 300K, respectively. Further studies show that the ultralow thermal conductivity of XI3 arises from the competition of vibrations between alkali metal atoms and halogen atoms. In addition, at 700K, the thermoelectric figure of merit ZT values of CsI3 and RbI3 are 4.10 and 1.52, respectively, at the optimal hole doping level, which indicates hypervalent triiodides are potential high performance thermoelectric materials.

Ignition control and waste heat assessment of spontaneous combustion gangue hill by gravity heat pipe group: a case study in Shanxi Province, China.

Spontaneous combustion gangue hill has attracted great attention due to serious environmental pollution and terrible geological disasters. However, the rich thermal resources inside are often ignored. In order to control the spontaneous combustion of gangue hill and utilize the internal waste heat resources, this project studied the combined treatment effect of 821 gravity heat pipes, laid 47 sets of temperature monitoring devices, evaluated the storage of waste heat resources, and proposed different waste heat utilization methods. The results show that (1) the positions of spontaneous combustion are all located on the windward slope. The highest temperature is in the range of 6 ~ 12m underground, exceeding 700 ℃. (2) The single-tube experiment of gravity heat pipe shows that the effective temperature control radius is 2m. The cooling effect is obvious in the range of 3 ~ 5m underground. However, the temperature rises at the depth of 1m underground. (3) After 90days of treatment of the gravity heat pipe group, the temperature at the depths of 3m, 4m, 5m, and 6m in the high-temperature zone dropped by 56 ℃, 66 ℃, 63 ℃, and 42 ℃, respectively. The maximum temperature drop exceeds 160 ℃. The average temperature drop in the middle- and low-temperature areas is between 9 and 21°C. (4) The concentration of harmful gases (CO, SO2, and H2S) decreases by more than 90%. The hazard level is greatly reduced. (5) The amount of waste heat resources contained within 10m of the spontaneous combustion gangue hill is 7.83E13J. Waste heat resources can be used for indoor heating and greenhouse cultivation. And, under the temperature difference of 50°C, 100°C, and 150°C, the electric energy generated by the heat through the thermoelectric conversion device in the high-temperature zone of the gangue hill is 4056.8 kWh, 7468.2 kWh, and 10,603 kWh, respectively.

Design and Experimental Investigation of a Thermoelectric Conversion Device with Power Management for Forest Fire Monitoring

Forest fires have long been a significant global problem. How to reliably accomplish the early warning and real-time monitoring of forest fires has become a pressing issue in order to limit the damage caused by forest fires. A novel technological approach for forest fire monitoring has been made possible by the quick development of wireless sensor network (WSN) technology. Currently, batteries are the primary source of power for WSNs used in forests, but frequent battery replacement will compromise the network for monitoring. As a result, the power supply is the key limit to its application in forest areas. This paper puts forward the thermoelectric conversion based on the Seebeck effect. Its notable feature is to convert heat energy into electric energy through the temperature difference between shallow soil and air. In the process of testing the device, the maximum voltage was 803.36 mV. At the same time, a power management system (PMS) for a thermoelectric conversion device was designed. The main feature of this system is that there is no need for an external control module. In the laboratory test, the minimum input power of this system was 200 mV. When the load resistance was 8 KΩ, the output power was 0.55 mW, and the maximum efficiency could reach 65.38% when the input was 500 mV, which fulfills the requirements of low cost and high reliability, providing a feasible solution for solving the energy limitation problem of WSNs in a forest area.

Future windows could generate electricity with multilayer film advances

Zinc oxide and tin oxide multilayers make an improved transparent material for thermoelectric conversion devices.

Mechanism of amorphous-like thermal conductivity in binary oxide Yb<sub>3</sub>TaO<sub>7</sub>

The materials with low thermal conductivity (<i>κ</i>) are both fundamentally interesting and technologically important in applications relevant to thermal energy conversion and thermal management, such as thermoelectric conversion devices, thermal barrier coatings, and thermal storage. Therefore, understanding the physical mechanisms of glass-like heat conduction in crystalline materials is essential for the development and design of low-<i>κ</i> materials. In this work, the microscopic phonon mechanism of glass-like low <i>κ</i> in binary simple crystal Yb<sub>3</sub>TaO<sub>7</sub> with fluorite structure is investigated by using the equilibrium molecular dynamics, phonon spectral energy density, and lattice dynamics. Meanwhile, the weberite-structured Yb<sub>3</sub>TaO<sub>7</sub> is also mentioned for comparison. The calculated <i>κ</i> indicates that fluorite Yb<sub>3</sub>TaO<sub>7</sub> has a glass-like low <i>κ</i> while weberite Yb<sub>3</sub>TaO<sub>7</sub> has a crystal <i>κ</i>. Such a low <i>κ</i> in fluorite Yb<sub>3</sub>TaO<sub>7</sub> is mainly due to the large difference in interatomic force between O-Yb and O-Ta. This different atomic bonding can significantly soften the phonon mode and thus limit phonon transport. To further describe the microscopic phonon thermal conduction, the single-channel model based on the phonon gas model is first used to calculate the total <i>κ</i>. However, the single-channel model significantly underestimates the <i>κ</i>, suggesting the presence of non-normal phonons in Yb<sub>3</sub>TaO<sub>7</sub>. Based on this, vibrational mode decomposition is conducted throughout the entire phonon spectrum of fluorite- and weberite-type Yb<sub>3</sub>TaO<sub>7</sub>. It is found that most modes in fluorite Yb<sub>3</sub>TaO<sub>7</sub> fall in the Ioffe–Regel regime and exhibit a strongly diffusive nature. Such diffusive modes cannot be described by the phonon gas model. Based on the decomposed phonon modes, the dual-channel model involving diffusive mode and propagating mode is used to describe the phonon thermal conduction, by which the obtained results accord well with the experimental values. The vast majority (> 90%) of heat in fluorite Yb<sub>3</sub>TaO<sub>7</sub> is found to be transported by diffusive modes rather than propagating modes. Consequently, the <i>κ</i> of fluorite Yb<sub>3</sub>TaO<sub>7</sub> increases with temperature rising, exhibiting a unique glass-like nature. In particular, contrary to conventional wisdom, the optical phonon mode in fluorite Yb<sub>3</sub>TaO<sub>7</sub> plays a significant or even decisive role in thermal conduction, which could serve as a new physical factor to adjust <i>κ</i> in solid materials. Overall, the new understanding of the link between chemical bonding and glass-like <i>κ</i> can contribute to the development and design of low-<i>κ</i> materials.

Liquid thermoelectric conversion devices composed of several organic solvents

We evaluated the performances of liquid thermoelectric conversion devices (LTEs) composed of nine organic solvents containing an Fe2+/Fe3+ redox pair against the electrolyte concentration (m). In protic solvents, i.e. methanol (Me), ethanol (Et), 1-propanol (Pr), and ethylene glycol (EG), the electrochemical Seebeck coefficient (α = d V/d T, where V and T are the electrode potential and temperature, respectively) increases with m in the small m region. Based on the ultraviolet—visible absorption spectroscopy, we interpreted the enhancement of α in terms of the OH− and/or H2O coordination to Fe3+, which was introduced by the crystal water of the solute. At a temperature difference (ΔT) of 30 K, the maximum value of the power factor of the Me LTE reaches 11.5 μW K−2m.

Realizing High Thermoelectric Performance of Ag/Al Co‐Doped Polycrystalline SnSe through Band Structure Modification and Hydrogen Reduction

AbstractSingle crystal tin selenide (SnSe) has a recorded high thermoelectric figure of merit (ZT) value of 2.6 at 923 K, but it is easy to form mechanical cracks and difficult to apply in thermoelectric conversion devices. Polycrystalline SnSe has better mechanical properties but inferior ZT values, which needs further optimization for applications. This work aims at enhancing the thermoelectric performance of polycrystalline SnSe through synergistic optimization of sliver (Ag) and aluminum (Al) co‐doping with the hydrogen reduction. The effects of Ag and Al doping on electronic transport properties are systematically investigated by density functional theory calculation and experimental measurement. Compared with pristine SnSe, Ag doping can effectively increase the hole concentration to 1.58 × 1019 cm−3 and improve the conductivity. Results also indicate that using Al dopant may slightly decrease the hole concentration but reduce the thermal excitation temperature, and introduce point defects reducing the lattice thermal conductivity through scattering phonons. In addition, the hydrogen reduction of sample powders before synthesis can effectively remove Sn oxides and reduce lattice thermal conductivity. At last, a state‐of‐the‐art maximum ZT value of 1.69 at 823 K is obtained in Ag0.01Al0.01Sn0.98Se. This study provides a theoretical basis and technical guidance for designing high‐performance polycrystalline SnSe.

Giant Thermopower of Hydrogen Ion Enhanced by a Strong Hydrogen Bond System.

Ionic thermoelectric materials based on organic polymers are of great significance for low-grade heat harvesting and self-powered wearable temperature sensing. Here, we demonstrate a poly(vinyl alcohol) (PVA) hydrogel that relies on the differential transport of H+ in PVA hydrogels with different degrees of crystallization. After the inorganic acid is infiltrated into the physically cross-linked PVA hydrogel, the ionic conductor exhibits a huge ionic thermopower of 38.20 mV K-1, which is more than twice the highest value reported for hydrogen ion transport thermoelectric materials. We attribute the enhanced thermally generated voltage to the movement of H+ in the strong hydrogen bond system of PVA hydrogels and the restrictive effect of the strong hydrogen bond system on anions. This ionic thermoelectric hydrogel opens up a new way for thermoelectric conversion devices using H+ as an energy carrier.

Improvement and Validation of the System Analysis Model and Code for Heat-Pipe-Cooled Microreactor

Heat-pipe-cooled microreactors (HPMR) use a passive high-temperature alkali metal heat pipe to directly transfer the heat of solid core to the hot end of the intermediate heat exchanger or thermoelectric conversion device, thus avoiding a single point failure. To analyze and evaluate the transient safety characteristics of an HPMR system under accident conditions, such as heat pipe failure in the core or a loss of system heat sink and other accidents, a previously developed model for transient analysis of a heat-pipe-cooled space nuclear reactor power system (HPSR) was improved and validated in this study. The models improved mainly comprise: (1) An entire 2-D solid-core heat transfer model is established to analyze the accident conditions of core heat pipe failure and system heat sink loss. In this model, radial and axial Fourier heat conduction equations are used to divide the core into r-θ direction control volumes. The physical parameters of the material in the control volume are calculated according to the volume-weighted average. (2) By coupling the heat transfer limit model and the two-dimensional thermal resistance network model, the transient model of a heat pipe for HPMR system analysis is improved. (3) Conversion system models are established to simulate the system characteristics of the advanced HPMR concept, such as thermoelectric conversion, Stirling conversion, and the open Brayton conversion analysis model. Based on the improved models, the HPMR system analysis program TAPIRSD was developed, which was verified by experimental data of the separated conversion components and the ground nuclear test device KRUSTY. The maximum deviation of the power output predicted by the energy conversion model is less than 8%. The accident conditions of the KRUSTY tests, such as load change, core heat pipe failure, and heat sink loss accident, were studied by using TAPIRSD. The results show that the simulation results of the TAPIRSD code agree well with the experimental data of the KRUSTY prototype reactor. The maximum error between the TAPIRSD code prediction and the measured value of the core temperature under accident conditions is less than 10 K, and the maximum deviation is less than 2%. The results show that the developed code can predict the transient response process of the HPMR system well. At the same time, the accuracy and reliability of the improved model are proved. The TAPIRSD is suitable for system transient analysis of different types of HPMRs and provides an optional tool for the system safety characteristics analysis of HPMR.

Enhancement of thermoelectric properties and first-principles calculations of Ag / Ti co-substituted Ca3Co4O9

Thermoelectric materials of Ca3Co4O9 with excellent comprehensive performance have stagnated the research of thermoelectric conversion devices due to their low thermoelectric conversion efficiency. Ca3-xAgxCo4-yTiyO9 was synthesized by double substitution at Ca and Co sites via a traditional solid-state method to change the microstructure and improve the thermoelectric properties in this paper. Ag and Ti co-substituted increase the porosity, reduce the concentration of Co4+ ions, and improve the Seebeck coefficient and power factor. The optimum substitute amount is x = 0.2, y = 0.2, and the Seebeck coefficient and power factor are 238.4 μV/K and 1481.9 μW/K2m. The first-principles calculation results show that the addition of Ti increases the covalent bond strength between Co–O atoms, and the addition of Ag narrows the gap, which is beneficial to the improvement of thermoelectric properties.

Multiple hydrogen bonding interactions toward rapidly self-healing, photothermal conversion elastomer composites

Despite the photothermal conversion elastomers were widespread used in solar power collection and shape-morphing devices, the fabrication of photothermal conversion elastomer integrated with low cost, fast self-healing, high healing efficiency, and comparable mechanical property, remained a challenge. To address this issue, we reported a kind of elastomer composites with fast self-healing and excellent photothermal conversion property through the multiple hydrogen bonding interactions between natural rubber (NR), carboxylate cellulose nanocrystal (C–CNC) and polydopamine (PDA). In these elastomer composites, NR acted as the elastic matrix and the C–CNC with rich carboxylic and hydroxy groups played the role as the reinforcement. Particularly, PDA with abundant hydroxy groups and secondary amines groups that was used as the photothermal agent, endowed these elastomer composites with photothermal conversion capability. Moreover, the formation of multiple hydrogen bonding networks endowed the elastomer with fast and spontaneous self-healing capability, and the healing efficiency of strain reached 92.2% within 5 min. Meanwhile, these elastomers showed excellent photothermal conversion performance and the photothermal conversion efficiency was 49.7%. Furthermore, these photothermal conversion elastomer composites present a great potential application in thermoelectric conversion and photo-triggered shape memory devices. • Natur rubber-based elastomer composite with multiple hydrogen bonds was developed. • The elastomer composites showed excellent mechanical property and elastic property. • The healing efficiency of the fast and spontaneous self-healing process was 92.2%. • The conversion efficiency of the stable photothermal conversion property was 49.7%. • The elastomer composites applied in thermoelectric conversion and photo-triggered actuators.

Performance of thermoelectric conversion device with power management module based on shallow soil-air temperature difference

The development of wireless sensor technology has provided an alternative research direction for monitoring of the Internet of Things. However, the practical application of wireless sensor technology is currently constrained by power supply requirements and the rather laborious task of replacing or maintaining the sensor batteries. In this paper, a wireless node power supply system based on the temperature difference between the shallow soil-air was designed. The distinguishing features of this device include application of a gravity heat pipe, thermoelectric generators (TEGs), copper heat fins, and radiators to absorb, transfer and convert the thermal energy. The study measured the performance of the proposed device in an experimental outdoor platform, the results show that in the 8 h monitoring of a day, the temperature difference of thermoelectric device ranged from 12.96k to 24.69k, the peak voltage of the device was 722.13 mV and the peak power was 3.62 mW when the proposed device was at the optimal external load. Furthermore a power management system was designed to increase the output voltage and eventually store it in the supercapacitor. In conclusion, The system provides an effective mechanism for solving the energy supply problem of wireless sensor.