• 대한기계학회:학술대회논문집
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• 대한기계학회 2003년도 춘계학술대회
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• pp.1499-1505
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• 2003

Rapid development of electronic technology requires small size, high density packaging and high power of electronic devices. So, in this paper, characteristics on oscillating heat pipe according to operating conditions(environment temperature, charging ratio of working fluid, inclination) based on experimental study was investigated. From the experimental results, $25^{\circ}C$environment temperature), R-141b(working fluid)40%(charging ratio) was best performace at others of inclination angle and The top heating mode of OCHP performed 80% efficiency of the bottom heating mode.

• 대한기계학회:학술대회논문집
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• 대한기계학회 2004년도 춘계학술대회
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• pp.1394-1399
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• 2004

Recently solar energy is representative in the technology development and spread of alternative energy. Specially in condition of solar collectors, they have had very various shape. This paper reports experimental study about the application of Oscillating Capillary Tube Heat Pipe to flat-plate solar collector. In conclusion, overall temperature distribution of OCHP was investigated by charging ratio and inclination angle. Respective charging ratio is 15%, 20%, 40% and respective inclination angle is horizontal, $30^{\circ}$, $45^{\circ}$, $60^{\circ}$, perpendicular. As a result of experiment, charging ratio 20% heat pipe has shown the most uniform temperature distribution and also performance of heat transfer has been the best.

• Journal of Advanced Marine Engineering and Technology
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• 제29권4호
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• pp.436-442
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• 2005

Rapid development of electronic technology requires small size, high density packaging and high power of electronic devices. In this paper, characteristics on oscillating heat pipe according to operating conditions (environment temperature, charging ratio of working fluid, inclination) based on experimental study was investigated From the experimental results $25^{\circ}C$(environment temperature) R-141b (working fluid) $40\%$ (charging ratio) was best performace at others of inclination angle and the top heating mode of OCHP performed $80\%$ efficiency of the bottom heating mode.

• 대한기계학회:학술대회논문집
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• 대한기계학회 2007년도 춘계학술대회B
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• pp.2148-2153
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• 2007

The electricity conversion-efficiency of solar cell for commercial application is about 6-15%. More than 85% of the incoming solar energy is either reflected or absorbed as heat energy. Consequently, the working temperature of the photovoltaic cells increases considerably after prolonged operations and the cell's efficiency drops significantly. PV/T refers to the integration of a PV module and a solar thermal collector in a single piece of equipment. By cooling the PV module with a fluid steam like air or water, the electricity yield can be improved. At the same time, the heat pick-up by the fluid can be to support space heating or service hot-water systems. In this study, a pulsating heat pipe solar heat collector was combined with single-crystal silicon photovoltaic cell in hybrid energy-generating unit that simultaneously produced low temperature heat and heat and electricity. This experiment was investigating thermal and electrical efficiency for evaluation of a PV/T system.

• 한국전산유체공학회지
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• 제21권1호
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• pp.86-93
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• 2016

In this paper, heat transfer characteristics of pulsating heat pipes are investigated with the diameter and the number of tubes through the computational analysis of thermal flow. The numerical simulation includes the phase change precess with VOF model using OpenFOAM software. The numerical code is modified for the phase change to occur with saturation temperature. The numerical results are compared with the previous ones to validate the present code. The resonable results have been obtained based on the mass transfer time relaxation parameter considering the density ratio. When the ratio of length to diameter and the number of tubes are on the decrease, the thermal resistances also tends to decrease in the pulsating heat pipes. These numerical results will supply the base line data to design and to manufacture the pulsating heat pipe.

• Journal of Advanced Marine Engineering and Technology
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• 제31권1호
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• pp.51-57
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• 2007

In process of reinforced concrete (RC) box structure. the heat of hydration may cause serious thermal cracking. In order to eliminate hydration heat of mass concrete. this paper reports results of hydration heat control in mass concrete structure using the pulsating heat pipe. There were three RC box molds($1.2{\times}l.8{\times}2.4m^3$) which shows a difference as compared with each other. One was not equipped with pulsating heat pipe. The others were equipped with pulsating heat pipe. All of them were cooled with natural air convection. The pulsating heat pipe was composed of serpentine type copper pipe with 10 turns (outer diameter: 4mm. inner diameter: 2.8mm). The working fluid was R-22 and its charging ratio was 40% by volume. The conditions such as the number of turns. the length and the pitch of the pulsating heat pipe and the size of concrete structure were changed. Based on these experiments, it was confirmed that this construction method using pulsating heat pipe was effective to remove hydration heat of mass concrete structure and thus it was possible to prevent harmful thermal crack and construction Period and costs of concrete structure would be cut down.

• 대한설비공학회:학술대회논문집
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• 대한설비공학회 2009년도 하계학술발표대회 논문집
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• pp.1379-1384
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• 2009

High power light emitting diode(LEDs), a strong candidate for the next generation general illumination applications are of interest. With major advantages of power saving, increased life expectancy and faster response time over traditional incandescent bulb, the LEDs are rapidly taking over many applications such as LCD backlighting, traffic light, automotive lighting, signage, etc. The increased electrical currents used to drive the LEDs have focused more attention on the thermal management because the efficiency and reliability of the solid-state lighting devices strongly depend on successful thermal management. There exist some problems that are caused by heat generation in the LED package, such as wire breakage, yellowing of epoxy resin, lifted chip caused by reflow of thermal paste chip attach and interfacial separation between LED package and silicon resin. The goal of this study is to analyze high power LED thermal properties of using pulsating heat pipe.

• 설비공학논문집
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• 제13권5호
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• pp.368-376
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• 2001

Performance of heat exchanger was evaluated to heat exchanger using oscillating heat pipe for waste heat recovery of low temperature. Oscillating heat pipe used in this study was formed to the closed loop of serpentine shapes using copper tubes. Heat exchanger was formed to shell and tube type and composed of low finned tube. R-22 and R-141b were used to the working fluids of tube side and their charging ratio was 40%. And, water was used to the working fluid of shell side. As the experimental parameters, the inlet temperature difference of heating and cooling part of secondary fluid and the mass velocity of secondary fluid were used. The mass velocity of secondary fluid was changed from 90 kg/$m^2s\; to\;190 kg/m^2$s from the experimental results, heat recovery rate was linearly increased to the increment of the mass velocity of secondary fluid and the inlet temperature difference of secondary fluid. Finally, the performance of heat exchanger was evaluated by using $\varepsilon$-NTU method. It was found that NTU was about 1.5 when effectiveness was decided to 80%.

• 대한설비공학회:학술대회논문집
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• 대한설비공학회 2008년도 동계학술발표대회 논문집
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• pp.578-583
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• 2008

Korea which has change of clear season is using unique heater by the name of On-dol being invented since ancient times. Floor-heating device has no radiator, and generates no noise and dust. It can obtain satisfied heating sense than other heating system in low room temperature. And also it is a pleasant system that equals bottom and top temperature in a room. The purpose of this study is to develop the Floor-heating device using pulsating heat pipe. It propose floor-heating device using pulsating heat pipe of the dry process which alternative polyethylene pipe(low XL pipe) that is used widely to existent floor heating system and produce pilot Experiment and analyzed operation condition and performance of most suitable. In this study, main purpose is to develop floor-heating system using pulsating heat pipe by finding an optimum working condition according to changing ratio and evaluating a performance.

• 대한설비공학회:학술대회논문집
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• 대한설비공학회 2006년도 하계학술발표대회 논문집
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• pp.352-356
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• 2006

As a basic study to develop heating panel, the purpose of this study was to know possibility as a floor heating panel. We investigated working conditions and performance of pulsating heat pipe. Tests were conducted under the next conditions; Working fluid were R-22 and R-134a, charging ratio 40% and 50%, temperature of inlet water $60^{\circ}C$ and $70^{\circ}C$, flow rates $1{\sim}3kg/min$. The experimental results indicate that the pulsating heat pipe charged 50% showed better performance than 40%, R-22 is more suited to the working fluid than R-134a, and it has a possibility which can be applied to floor heating panel using a pulsating heat pipe.