• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.26 no.6
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• pp.257-262
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• 2014

This paper describes an experimental study for heating performance that can be used in R-134a automobile heat pump systems. The heat pump system is widely studied for heating system in zero-emission vehicles to attain both the small power consumption and the effective heating of the cabin. This paper presents the experimental results of the influence on heating capacity and coefficient of performance of heat pump system. Tests were performed with different sizes of internal and external heat exchangers, and refrigerant flow rate was also considered in two-way flow devices. In addition, the heat, air, and water sources with the heat pump system were examined. The experimental results with the heat pump system were used to analyze the impact on performances. The best combination of performance was A-inside heat exchanger, B-outside heat exchanger, and B-flow device, respectively. In addition, a water heat-source was found to give roughly 40% of better performance than an air heat-source heat pump system.

• 한국전산유체공학회:학술대회논문집
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• 2011.05a
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• pp.225-229
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• 2011

The aluminum composite panel are widely used for the external materials of high rise building because of well insulation of heat and sound and improved Constructability. However, the polyethylene in main material of the aluminum composite panel shows weakness in thermal and fire resistances. For this reason, flame is spread more quickly when the fire break out. Therefore, the potentiality of fire spread to the exterior wall is high due to difficulty of early extinguishment and effect of external air. In this study, numerical investigation was performed by using FDS program for flame spread characteristics with various external air velocity and direction in ten-story building with the aluminum composite external materials. As a result, the flame spread velocity is 0.134m/s and it takes 224 seconds for flames to spread to the 10th floor without external air velocity. however, the flame spread velocity decreases 40% and it takes 348 seconds for flames to spread to the 10th floor when external air velocity is 2.5 m/s. and air direction is little effect compared to air velocity.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.20 no.1
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• pp.26-34
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• 2008

Heat recovery ventilator(HRV) is recommended to improve indoor air quarlity (IAQ) and energy conservation in apartment houses. Recently, in Korea, HRV is produced from many manufacturers. However, there have been not so many experiences to apply HRV in apartment houses and verification on the performance such as heat exchange efficiency, carry-over rate, internal leakage, etc. have not been carried out sufficiently. So in this study, fan performance, heat exchange efficiency, air leakage, internal exhaust leakage, external leakage and sound level of HRV were examined for selected HRV models under domestic and international standard. Results of performance test, there were need to improve latent heat exchange efficiency and sound level of HRV.

• Journal of the Korean Society of Manufacturing Process Engineers
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• v.16 no.4
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• pp.147-152
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• 2017

In the present study, we used a loop thermosyphon heat exchanger consisting of condensers with internal fins and external plate fins which are 480 mm wide, 68 mm long, and 1,000 mm high. The heat transfer pipes in the heat exchanger were 15 mm in diameter and 1,000 mm in length, and 98 heat transfer pipes were installed in the heat exchanger. According to the experimental results, as the spaces between the internal discontinuous pins decreased, the frequency of pressure drops increased and changes in temperature at the outlet of the condenser were shown to be a little smaller. Therefore, we can see that as the spaces between internal discontinuous pins decreased, the heat transfer performance increased. For the loop heat pipe heat exchanger consisting of a condenser with internal and plate fins, as the temperature of the air flowing into the condenser increased, the condensation heat transfer rate also increased, and as the condenser refrigerant inflow temperature increased, the condensation heat transfer rate increased as well.

• Journal of the Architectural Institute of Korea Structure & Construction
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• v.33 no.12
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• pp.91-98
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• 2017

In this study, the effect of window installation position in the residential building with the external insulation was numerically investigated in terms of insulation performance and heating/cooling energy consumption. For different window positions, 2-D heat transfer simulation was conducted to deduce the linear thermal transmittance, which was inputted to the dynamic energy simulation in order to analyze heating/cooling energy consumption. Simulation results showed that the linear thermal transmittance ranges from 0.05 W/mK to 0.7 W/mK, and is reduced as the window is installed near the external finish line. Indoor surface temperature and TDR analysis showed that the condensation risk is the lowest when the window is installed at the middle of the insulation and wall structure. It was also found that the window installation near the external finish can reduce the annual heating/cooling energy consumption by 12~16%, compared with the window installation near the interior finish. Although the window installation near the external finish can achieve the lowest heating/cooling energy consumption, it might lead to increased condensation risks unless additional insulation is applied. Thus, it can be concluded that the window should be installed near the insulation-wall structure junction, in consideration of the overall performance including energy consumption, condensation prevention and constructability.

• Journal of Energy Engineering
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• v.23 no.2
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• pp.207-216
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• 2014

The energy loss can be divided into the loss caused by heat transfer and the loss caused by air flow. Heat transfer is the loss resulting from the heat transmittance of external wall, roof, and floor, and represents one of the most vulnerable elements of existing buildings. To prevent such loss, it is necessary to increase the mean heat transmittance of entire external wall, including the window, to a level above the standard regional value and ensure the air-tightness of window. The old buildings have the structure which is prone to the loss of greater air flow due to the air infiltration through the exit/entrance door upward along the stairway by the stack effect and simultaneous suction of air from each floor, and becomes even vulnerable to the loss of heat insulation for each floor, although the external wall and windows are the most vulnerable parts. The improvement plans for each floor need to be submitted in tandem with the diagnosis of whole building, regarding the diagnosis plan and energy improvement measures based on the survey of site, rather than adhering to the misconception that the replacement of window alone will result in energy-savings.

• Journal of Haehwa Medicine
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• v.8 no.2
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• pp.171-189
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• 2000

By Literatural studying on migraine, The results were obtained as fallow : 1. A different name on migraine were called hemicrania(頭偏痛, 邊頭痛, 偏頭風). 2. In the cause of a disease in migraine, the cases were clasified into the fallowing kind : internal cause were a decline in energy and blood(氣血具虛), external cause were outside evil(外邪) in wind cold heat wetness(風寒暑濕), non internal, external cause were exhaustion. The right side migraine were concerned phlegm heat, the right side migraine were concerned wind decline in blood. 3. Migraine is appeared on the side, For the reason, liver function in excess of normal limits(肝陽上亢), a sudden of liver fire(肝火) is becomeed of invasion upon soyangkuong(少陽經) in internal external cause 4. Usage method of medicines is appeared that order underclothes theraphy(內服法), to pump out in nose theraphy, to join head theraphy(頭點法), heating smoke theraphy(熏煙法) 5. CNIDII RHIZOMA(川芎) is in mostly general use for migraine, in that order LEDEBOURIELLAE RADIX(防風) ANGELICAE DAHURICAE RADIX(白芷) ASARI HERBA CUM RADICE(細辛) NOTOPTERYGII RHIZOMA(羌活) GLYCYRRHIZAE RADIX(甘草) CHRYSANTHEMI FLOS(菊花) BUPLEURI RADIX(柴胡) SCUTELLARIAE RADIX(黃芩) ANGELICAE GIGANTIS RADIX(當歸) GYPSUM FIBROSUM(石膏) MENTHAE HERBA(薄荷) GLYCYRRHIZAE RADIX(炙甘草) VITICIS FRUCTUS(蔓荊子), nature is in mostly general hot warm(辛溫), bitter cold(苦寒), guikuong(歸經) is in mostly general liver gall kuong(肝膽經), efficacy is in mostly general to remove wind pain (祛風止痛) and to down fire(瀉火).

• Journal of the korean Society of Automotive Engineers
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• v.11 no.1
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• pp.20-30
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• 1989

The unsteady conjugate forced convection-conduction heat transfer from a plate fin is numerically studied. The external forced flow is steady but the temperature of the fin base is an exponential change with time. Therefore, the unsteady energy equations of the fluid and the fin are solved simultaneously under the conditions of equality in heat flux and temperature at the fluid-fin interface at every instant of time. Numerical results are given for various quantities of interest including the local heat transfer coefficient, the local heat flux, the total heat transfer rate and the temperature distribution of fin under the effects of the convection-conduction parameter and the ratio of thermal diffusivities. The results of the present numerical solution have been compared with those of the conventional fin theory.

• Journal of Advanced Research in Ocean Engineering
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• v.4 no.1
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• pp.1-6
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• 2018

Subsea pipelines are designed to transport mixtures of oil, gas, and their associated impurities from the wellhead that can have temperatures as high as $100^{\circ}C$, while the external temperature can be as low as $5^{\circ}C$. Heat can be lost from the subsea pipeline containing high-temperature fluid to the surrounding environment. It is important that the pipeline is designed to ensure that the heat loss is small enough to maintain flow and avoid the unwanted deposition of hydrate and wax, which occurs at a critical temperature of approximately $40^{\circ}C$. Therefore, it is essential to know the heat loss of subsea pipelines under various circumstances. This paper presents a comparison between numerical analyses and existing theoretical formulas for different backfills and burial depth.

• Proceedings of the KSME Conference
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• 2002.08a
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• pp.725-728
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• 2002

A separate type thermosyphon can be utilized as a cooling device of electronic equipments (such as CPU of a personal computer or notebook). This study was carried out to investigate the cooling effect of separate type thermosyphon and to find the adequate parameters affecting the separate type thermosyphon. The heat transfer characteristics of separate type thermosyphon were obtained from experimental results. A $50{\times}50{\times}2 mm$ heat source was copied after CPU for the experiments. The results indicate that the device is capable of dissipating 60W of thermal energy and keeping the heat plate surface temperature under 50'E and the device can transfer heat from the evaporator to the condenser through natural circulation (without any external driving forces). Some transport phenomena of the working fluid and the heat transfer characteristics of the loop were observed in the experiments and are discussed in detail below.