• Journal of IKEEE
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• v.19 no.2
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• pp.210-218
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• 2015

In this paper an auto-switching energy harvesting circuit using vibration and thermoelectric energy is proposed. Since the maximum power point of a thermoelectric generator(TEG) output and a vibration device(PEG) output is 1/2 of their open-circuit voltage, an identical MPPT controller can be used for both energy sources. The proposed circuit monitors the outputs of the TEG and PEG, and chooses the energy source generating a higher output voltage using an auto-switching controller, and then harvests the maximum power from the selected device using the MPPT controller. The proposed circuit is designed in a $0.35{\mu}m$ CMOS process and its functionality has been verified through extensive simulations. The designed chip occupies $1.4mm{\times}1.2mm$ including pads.

• Korean Journal of Metals and Materials
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• v.47 no.4
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• pp.248-255
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• 2009

A micro thermoelectric device was processed by electroplating the n-type Bi-Te nanowires and ptype Sb-Te nanowires into an alumina template with 200 nm pores. Power generation characteristics of the micro devices composed of the Bi-Te nanowires, the Sb-Te nanowires, and both the Bi-Te and the Sb-Te nanowires were analyzed with applying a temperature difference of $40^{\circ}C$ across the devices along the thickness direction. The n-type Bi-Te and the p-type Sb-Te nanowire devices exhibited thermoelectric power outputs of $3.8{\times}10^{-10}W$ and $4.8{\times}10^{-10}W$, respectively. The output power of the device composed of both the Bi-Te and the Sb-Te nanowires decreased to $1.4{\times}10^{-10}W$ due to a large electrical resistance of the Cu electrode connecting the Bi-Te nanowire array with the Sb-Te nanowire array.

• Proceedings of the KSME Conference
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• 2007.05b
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• pp.1942-1947
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• 2007

A thermoelectric module can be used for cooling or power generation. The basic requirements to achieve a significant thermoelectric performance are the same for both generators and coolers. Thermoelectric modules with $Bi_2Te_3$ materials are usually employed in the cooling applications below room temperature but it can also be used for the power generation in the similar temperature range. In the present study, the power generation with a $Bi_2Te_3$ thermoelectric module has been investigated. The temperature difference between the hot and cold sides of the module is maintained with electric heater and cold water from the circulating water bath. The result shows that the electric current generated increases with temperature difference and decreases with the load resistance. However, the voltage increases with both the temperature difference and load resistance. The electric power increases with temperature difference and it has the maximum value when the load resistance is about 4 ${\Omega}$ for a given device.

• Journal of IKEEE
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• v.20 no.2
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• pp.174-176
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• 2016

In this study, we maximize the temperature difference between the ends of a HgTe nanoparticle(NP) thin film on a thermoelectric platform with a through-substrate via. The thermoelectric characteristics of the HgTe NP thin film show p-type behavior and its Seebeck coefficient is $290{\mu}V/K$. In addition, we demonstrate the possibility of wearable thermoelectric devices transforming body heat into electricity from through-substrate via thermoelectric platforms on human skin.

• Journal of the Korean Society of Industry Convergence
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• v.22 no.2
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• pp.219-226
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• 2019

This paper describes the development of a 500W DC/DC converter for use with a thermoelectric module(TEM). A thermoelectric device is a structure in which a P-type semiconductor and an N-type semiconductor are electrically connected in series and thermally connected in parallel. There is a feature that an electromotive force is generated by making a temperature difference between both surfaces of a thermoelectric element. This feature can be used as a renewable power source without the need for fossil energy. The proposed converter boosts the low generation voltage of the thermoelectric element to secure the voltage for the grid connection. This converter is a combination of a resonant converter for boosting and a boost-converter for output voltage control. This structure has an advantage that a voltage can be stepped up at a high efficiency and precise output voltage control is possible. We carry out simulations and experiments to verify the validity.

• Journal of the Korean Society of Industry Convergence
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• v.27 no.4_2
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• pp.981-989
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• 2024

In recent years, there has been a growing focus on preserving the global environment and utilizing resources efficiently. The significance of energy conservation has led to the development of systems that recycle waste heat from factories and use eco-friendly refrigerants. This study aims to enhance the performance of adsorption-desorption systems using thermoelectric devices, which are known for their ability to convert temperature differences into electrical energy. The research focuses on improving the efficiency of these systems by integrating thermoelectric modules to cool the adsorption side and heat the desorption side, thus enhancing overall system performance. The experiments utilized a typical thermoelectric device and silica gel as the adsorbent. Key experimental parameters included varying the inlet air temperature and relative humidity on the desorption side. The results indicated that increasing the relative humidity of the inlet air on the desorption side significantly enhanced the overall mass transfer coefficient while reducing the completion time of the process. Similarly, higher inlet air temperatures led to an increase in the mass transfer coefficient and a decrease in process completion time. These findings suggest that optimizing the operational conditions of thermoelectric devices can substantially improve the performance of adsorption-desorption systems, offering potential benefits for applications in ventilation systems and other related fields.

• Journal of Powder Materials
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• v.12 no.4 s.51
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• pp.255-260
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• 2005

Direct solid state synthesis by hot pressing has been applied in order to produce high efficiency $Zn_4Sb_3$ bulk specimens. Single phase $Zn_4Sb_3$ with 98.5% of theoretical density was successfully produced by direct hot pressing of elemental powders containing 1.2 at.% excess Zn. Thermoelectric properties as a function of temperature were investigated from room temperature to 600 K and compared with results of other studies. Transport properties at room temperature were also evaluated. Thermoelectric properties of single phase $Zn_4Sb_3$ materials produced by direct synthesis were measured and are comparable to the published data. Direct solid state synthesis by hot pressing provides a promising processing route in this material.

• Journal of the Korean Institute of Telematics and Electronics A
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• v.32A no.1
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• pp.159-165
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• 1995

A double-heterostructure mesa-stripe-geometry laser diode integrated with thermoelectric Peltier cooler has been designed and fabricated. Epi-layers have been grown by metal organic chemical vapor deposition(MOCVD) method. Peltier cooling effect has been measured for devices with a mesa width of 14$\mu$m and a cavity length of 380$\mu$m. The effects of thermoelectric cooling could be shown by measuring the optical output of the laser with the increase of the current in the thermoelectric cooler. While the input courrent of the laser was maintained at 250mA, the optical output was decreased from 4.8mW to 3.8mW due to heating, but with the thermoelectric cooler on the optical output power was recovered by more than 40%. The results show that the complicated cooling device is not needed since the cooling can be achevied by the developement of the fabrication processing.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.35 no.2
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• pp.119-128
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• 2022

Recent advancement of Internet of Things (IoT) and energy harvesting technology enable realization of flexible thermoelectric energy harvester (f-TEH), with technological prowess for use in biomedical monitoring system integrated applications. To expand a flexible thermoelectric energy harvesting platform, the f-TEH must be required for optimized flexible thermoelectric materials and device structure. In response to these demands related to thermoelectric energy harvesting, many research groups have investigated various f-TEHs applied as a power source for wearable electronics. As a key member of the f-TEH, film-based f-TEHs possess significant applicability in research to realize self-powered wearable electronics, owing to their excellent flexibility, low thermal conductivity, and convenient fabrication process. Thus, based on the rapid growth of thermoelectric film technology, this review aims to overview comprehensively the f-TEH made of various inorganic/organic thermoelectric materials including developed fabrication methods, high thermoelectric performance, and wide-range applications.

• Korean Journal of Materials Research
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• v.21 no.8
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• pp.456-460
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• 2011

Microelectromechanical systems (MEMS)-fabricated suspended devices were used to measure the in-plane electrical conductivity, Seebeck coefficient, and thermal conductivity of 304 nm and 516 nm thick InGaAlAs films with 0.3% ErAs nanoparticle inclusions by volume. The suspended device allows comprehensive thermoelectric property measurements from a single thin film or nanowire sample. Both thin film samples have identical material compositions and the sole difference is in the sample thickness. The measured Seebeck coefficient, electrical conductivity, and thermal conductivity were all larger in magnitude for the thicker sample. While the relative change in values was dependent on the temperature, the thermal conductivity demonstrated the largest decrease for the thinner sample in the measurement temperature range of 325 K to 425 K. This could be a result of the increased phonon scattering due to the surface defects and included ErAs nanoparticles. Similar to the results from other material systems, the combination of the measured data resulted in higher values of the thermoelectric figure of merit (ZT) for the thinner sample; this result supports the theory that the reduced dimensionality, such as in twodimensional thin films or one-dimensional nanowires, can enhance the thermoelectric figure of merit compared with bulk threedimensional materials. The results strengthen and provide a possible direction in locating and optimizing thermoelectric materials for energy applications.