• Proceedings of the KSME Conference
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• 2007.05a
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• pp.1455-1458
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• 2007

In this research, a polycrystalline silicon (poly-Si) film layer for micro thermoelectric generator (TEG) was fabricated. The fabrication process of the thermoelectric poly-Si film layer is explained. The P-type and N-type poly-Si films were fabricated on a tetra ethoxy silane (TEOS) layer with a supporting Si wafer. Seebeck coefficient and electrical conductivity were measured, including the transport properties such as the hall coefficient, hall mobility and carrier concentration. The design parameters for a rapid thermal process (RTP) were decided based on the experimental results. The measured power factors of the P-type and N-type were $21.2\;{\mu}Wm^{-1}K^{-2}$ and $26.7\;{\mu}Wm^{-1}K^{-2}$, respectively.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.59 no.10
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• pp.1845-1849
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• 2010

We have proposed and fabricated a Buck-Boost DC to DC Converter for Thermoelectric generator (TEG) with constant output voltage suitable for battery chargers or constant voltage supplies in the range of several watt. The experimental and simulation results have shown that the proposed method allows stable operation with maximum 86% power transfer efficiency. The proposed circuit has a merit in cost and miniaturization of a system compared to conventional MPPT algorithms, because the proposed method adopts only analog circuit without DSP or micro controller unit for calculating peak power point by iterative methods.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.28 no.5
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• pp.594-603
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• 2004

Several desiccant cooling systems have been developed in terms of cost and performance. In this study a fin-tube exchanger has been used for liquid desiccant dehumidification system. This dehumidifier has been designed to study the absorption characteristic of the aqueous triethylene glycol(TEG) solution which has the flow range from 20 to 50 LPM. The dehumidifier performance characteristics of working factor variables such as inlet solution flow rate, air flow rate, solution concentration and brine temperature have been analyzed. This dehumidifier has the ability to provide running while saving the latent heat load of total energy. The result of this experiment can provide useful data for hybrid air conditioning system.

• Proceedings of the KSME Conference
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• 2003.11a
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• pp.25-30
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• 2003

Several desiccant cooling systems have been developed in terms of cost and performance. In this study a fin-tube exchanger has been used for liquid desiccant dehumidification system. This dehumidifier has been designed to study the absorption characteristic of the aqueous triethylene glycol(TEG) solution which has the flow range from 20 to 50 LPM. The dehumidifier performance characteristic of working factor variables such as inlet solution flow rate, air flow rate, solution concentration, solution temperature, brine temperature, air temperature and inlet air relative humidity has been analyzed. The result of this experiment can provide useful data for hybrid air conditioning system.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.25 no.12
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• pp.1756-1765
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• 2001

The heat and mass transfer process between the falling liquid desiccant(TEG) film and the air in counter flow at the dehumidifier of desiccant cooling system were investigated. The governing equations with appropriate boundary and interfacial conditions describing the physical problems were solved by numerical analysis. As a result, the effects of the design parameters and the outside air conditions on the rates of dehumidification and sensible cooling were discussed. The results of the dehumidification and sensible cooling rates were compared with those of the cross flow at the same conditions.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.7 no.3
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• pp.512-520
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• 1995

This study investigates the simultanceous heat and mass transfer between a falling desiccant film and air in cross flow at the interface. The application of this work is the optimization of falling film evaporators for use in potential hybrid air conditioning systems. The specific geometry considered is liquid TEG films falling along the vertical cooled surfaces of a channel with air in cross flow. The equations to describe the coupled heat and mass transfer between a falling desiccant film and air in cross flow for a falling film evaporator have been presented and solved numerically. The effects of important design and operating variables on the evaporator performance predicted by the parametric numerical analysis and suggestions for performance improvements of the evaporator are presented.

• Honam Mathematical Journal
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• v.43 no.2
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• pp.239-258
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• 2021

In the present paper, we introduce the study of slant lightlike submanifolds of indefinite nearly Kaehler manifolds. After proving some geometric results for the existence of slant lightlike submanifolds of indefinite nearly Kaehler manifolds, we give a non-trivial example of this class of lightlike submanifolds. Then, we derive some conditions for the integrability of the distributions associated with slant lightlike submanifolds of indefinite nearly Kaehler manifolds. Consequently, we study totally umbilical slant lightlike submanifolds of indefinite nearly Kaehler manifolds. Subsequently, we investigate minimal slant lightlike submanifolds of indefinite nearly Kaehler manifolds.

• Honam Mathematical Journal
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• v.45 no.4
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• pp.629-647
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• 2023

We introduce the study of a new class of a lightlike submersion d. Then, we derive a relationship between the holomorphic section 𝜙 : K₁ → K' from a screen generic lightlike submanifold of an indefinite Kaehler manifold K₂ onto an indefinite almost Hermitian manifold K', and show that for this case K' must be an indefinite Kaehler manifold. Then, we derive a relationship between the holomorphic sectional curvatures of K₂ and K'. Finally, we present a classification theorem for a screen generic lightlike submersion, giving the relationship between the sectional curvatures of the total space K₂ and the fibers.

• Journal of IKEEE
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• v.20 no.4
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• pp.373-377
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• 2016

This paper presents a low power boost converter using offset controlled Zero Current Sensor (ZCS) control for thermoelectric energy harvesting.[1] [5] Offset controlled ZCS uses adjustable pre-offset that is controled by 6bit code each connected gate of NMOS for switching. Offset controlled ZCS demonstrates an efficiency that is higher than using analog comparator ZCS and that is smaller area than using delay line ZCS. Experimentally, the offset controlled ZCS system consumes 10 times less power than analog comparator ZCS based system at similar performance.

• Journal of the Institute of Electronics Engineers of Korea SD
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• v.48 no.10
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• pp.15-19
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• 2011

We have proposed a maximum power point tracking (MPPT) circuit for thermoelectric generator (TEG) using a Boost converter. The key point of the proposed MPPT circuit is that the duty ratio of the boost converter automatically moves to Maximum Power Point by comparing of consecutive sampling voltage using two comparators. From the simulation results, we showed that the proposed circuit can find the maximum power point within 2 CLK periods and to generate optimal PWM signal within 3 CLK periods. The proposed MPPT circuit was designed by using a CMOS 0.18 um process, and it is now on the fabrication.