• 한국진공학회:학술대회논문집
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• 한국진공학회 2016년도 제50회 동계 정기학술대회 초록집
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• pp.300.2-300.2
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• 2016

Increasing of the demand for energy savings for buildings, thermal barrier films have more attracted. In particular, as heat loss through the windows have been pointed out to major problems in the construction and automobile industries, the research is consistently conducted for improving the thermal blocking performance for windows. The main theory of the technology is reflect the infrared rays to help the cut off the inflow of the solar energy in summer and outflow of the heat from indoors in winter to save the energy on cooling and heating. Furthermore, this is well known for prevent glare, reduces fading caused by harmful ultraviolet radiation and easy to apply on constructed buildings if it made as a film. In addition to these advantages, apply the transparent electrode to eliminate condensation by heating. Generally ITO is used as a transparent electrode, but is has a low stability in environmental factors. In this study, ITO and its alternative, ATO, is deposited by sputtering system and then the characteristic is evaluated each material based thermal barrier thin film. The optical property was measured on wide range of wavelength (200 nm 2500 nm) to know the transparency in visible wavelength and reflectivity in IR wavelength range. The electrical property was judged by sheet resistivity. Finally the changes of the temperature and current of the deposited film was observed while applying a DC power.

• 설비공학논문집
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• 제19권3호
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• pp.228-234
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• 2007

Opening an ancient tomb interior can deal fair damage for preservation in long period because of high moisture. In this study, a duct-type HVAC system was installed to preserve an ancient tomb and temperature and humidity was measured to analyze heat environment. Armhole was measured to search whether an ancient tomb receives effects of vibration caused by a duct-type HVAC system. According to the measured data, temperature in an ancient tomb is kept adaptively in conservation regardless of a duct-type HVAC system installation when it rains in summer. The other side, humidity is kept adaptively in conservation when installed duct-type HVAC system. But when it is in natural state, a lot of humidity by dew condensation phenomena. So it needs a duct-type system for an ancient tomb conservation. In the case of vibration, measurement value of 3 satisfy control but Germanic DIN 4150 does not satisfy. Therefore, equip must be such that it can prevent vibration for safety.

• 대한설비공학회:학술대회논문집
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• 대한설비공학회 2006년도 하계학술발표대회 논문집
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• pp.953-958
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• 2006

Perimeter zone has been reinforced by active systems, such as fan-coil units, because it causes an increase in heating and cooling loads, dew condensation in winter, or discomfort with cold-draft to residents in buildings, through poor insulation by light-weighed skin due to progressing multi-storied buildings and skyscrapers. However, because these active systems raise Its capacity so that fossil fuel is used as much as they are added, and ultimately, greenhouse effect is urged, we proposed BIPV system functioned as solar collector which can substitute active system. As an early stage, heat balance equation in steady-state by Fortran was used not only for pre-heating effect and electric power capacity during the day in winter, but also for electric power capacity during day in slimmer and sky radiation effect during night in summer. Especially, we should have considered shading on PV, since even a little bit of it makes the efficiency too low for the PV to work. Still, when the flux of pre-heated air was increased to make air-barrier, its temperature was not enough to make it because the speed of heat exchange was too fast to warm up the air, thus the capacity to meet the condition was evaluated, and electric power from PV was made used for it.

• 한국유체기계학회 논문집
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• 제17권5호
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• pp.11-18
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• 2014

Chilled Beam system is the kind of water-air system which reduces the conveyance energy for air conditioning as well as allows efficient installation and comfortable indoor environment, and has been increasingly popular mainly in Europe. To effectively install such Chilled Beam system domestically, it is necessary to develop the product considering domestic climatic condition and the requirements for air conditioning system, and particularly the way to deal with condensation during operation of cooling system in summer shall be provided. In this study, the optimal design on induction structure of Chilled Beam unit was carried out through a numerical method, and the performance test for the prototype of unit was conducted in a real-scale experiment facilities of Chilled Beam unit. While the flowrate of 1st air is 101.3 CMH, the pressure in pressure chamber is 158.7 Pa and the cooling capacities of 1st air side and 2nd air side are 498.1 W and 709.5 W respectively.

• Asian Journal of Atmospheric Environment
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• 제8권2호
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• pp.96-107
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• 2014

Extreme recovery of the thermal energy from the combustion of flue gas may bring about early gas condensation resulting in the increased formation of nitric acid vapor. The behavior of the nitric acid formed inside the stack and in the atmosphere was investigated through a computer-aided simulation in this study. Low temperatures led to high conversion rates of the nitrogen oxide to nitric acid, according to the Arrhenius relationship. Larger acid plumes could be formed with the cooled flue gas at $40^{\circ}C$ than the present exiting gas at $115^{\circ}C$. The acid vapor plume of 0.1 ppm extended to 25 m wide and 200 m high. The wind, which had a seasonal local average of 3 m/s, expanded the influencing area to 170 m along the ground level. Its tail stretched 50 m longer at $40^{\circ}C$ than at $115^{\circ}C$. The emission concentration of the acid vapor in the summer season was a little lower than in the winter. However, a warm atmosphere facilitated the Brownian motion of the discharged flue gas, finally leading to more vigorous dispersion.

• 한국농촌건축학회논문집
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• 제23권4호
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• pp.63-71
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• 2021

The purpose of this study was to investigate whether the standard models for rural housing and wooden housing model have performance for hygrothermal and to propose a way of improvement relevant to hygrothermal performance for those models. All of the models to be analyzed were found to have some parts that were absent of stability in terms of performance for hygrothermal. In the process of analyzing the causes and proposing improvement measures, the following conclusions were derived. Fist, The exterior surface of the structure should be composed of a structure with good moisture permeability, and for the interior surface, a variable vapor retarder paper should be applied in consideration of the reverse condensation phenomenon in summer. Second, in terms of performance for hygrothermal, applications of external insulation plaster finish to the exterior wall or of ventilation method using a rafter vent on the roof should be avoided. Third, a rain screen method with a ventilation layer should be applied to the exterior wall, and a method of constructing ventilation layer separated from the insulation layer with a vapor retarder paper should be applied to the roof. Fourth, the application of insulation materials having capillary action, such as wood fiber insulation board or cellulose insulation board, contributes to more stable performance for hygrothermal.

• 한국산학기술학회논문지
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• 제10권1호
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• pp.52-57
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• 2009

본 논문은 실내 외의 온 습도변화에 따른 효율변동을 고려하여 폐열회수 환기장치의 성능을 예측할 수 있는 프로그램을 개발하였다. 국내의 외기조건에서 폐열회수 환기장치의 성능에 대한 기초자료를 얻기 위하여 고효율기자재 인증조건을 만족하는 풍량 $250m^3/h$의 일본 M사의 제품을 선정하였다. 폐열회수 환기장치를 설치할 경우 서울은 난방부하 69.1%, 냉방부하 59.4%의 절감효과가 나타났고, 부산은 난방부하 66.4%, 냉방부하 59.6%의 절감효과가 나타났다. 동절기의 가습부하는 강릉이 3월에 $0.737{\ell}/h$의 최대 가습부하가 발생하고, 하절기의 제습부하는 목포가 8월에 $1.008{\ell}/h$의 최대 제습부하가 발생한다. 동절기에 남부지방과 동해안지역은 배기측에 응축 또는 응결이 발생하지 않으나 그 외의 지역은 발생한다. 따라서 남부지방과 동해안지역을 제외한 지역에서는 동절기에 배기측에 응축 또는 응결이 발생하지 않도록 방지책을 강구하여야 한다.

• 보존과학회지
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• 제25권2호
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• pp.179-196
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• 2009

논산 개태사지석불입상(보물 제219호)은 담회색을 띠고 부분적으로 장석 반정을 함유하고 있는 중립 내지 조립질의 화강섬록암으로 구성되어 있다. 구성암석의 전암대자율은 평균 12.06(${\times}10^{-3}$ SI unit)으로 개태사지 배후의 천호산 ($0.19{\times}10^{-3}$ SI unit) 노두와는 많은 차이를 보이고 있어 석재의 외부 유입 가능성이 제기된다. 이 석불입상은 우협시불의 박리(35.2%), 본존불의 시멘트 보수물질(21.1%) 및 먼지(25.0%)가 주요한 손상현상으로 밝혀졌다. 초음파 속도는 본존불 2850.2m/s, 좌협시불 2648.4m/s, 우협시불 2644.5m/s로 측정되었다. 이를 통해 산정한 일축압축강도는 우협시불이, 부위별로는 대좌에서 상대적으로 낮은 강도를 나타내어 손상도 평가 결과와 일치하였다. 석불입상이 봉안된 보호각 내부의 연평균 기온은 $13.7^{\circ}C$, 상대습도는 79.0%로, 계절에 따른 보호각 내부의 환경 변화는 근본적으로 외부의 변화를 따르나 미기후 변동이 심하지 않아 비교적 안정된 실내 환경이 유지되고 있다. 석불입상의 대좌 표면에서는 봄과 여름철에 결로가 발생하는 것으로 확인되었으며, 겨울철에는 동결파괴가 우려된다. 이는 훼손도 평가와 초음파 탐사 결과에서 나타난 대좌의 풍화 및 강도 저하의 근본적인 요인일 가능성이 매우 크다. 따라서 봄과 여름철에 집중 강우 시 실내의 제습과 한겨울에 기온 강하를 저감시킬 수 있는 조치가 필요하다.

• Journal of Biosystems Engineering
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• 제29권6호
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• pp.521-530
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• 2004

The solar powered water pump is very ideal equipment because solar power is more intensive when the water is more needed in summer and it is very helpful in the rural area, in which electrical power is not available. The average solar radiation power is $3.488\;kWh/(m^2{\cdot}day)$ in Korea. In this study, the experimental system of the water pump driven by the radiation energy were designed, assembled, tested and analyzed fur realizing the solar powered water pump. Energy conversion ken radiation energy to mechanical energy by using n-pentane as operating material was done and the water pumping cycles were able to be continued. The quantity of the water pumped per cycle ranged from 2 L to 10 L depending on the level of the valve open area far the vapour supply. The average quantity was about 4,366 cc. The thermal efficiency was about $0.018\%$. The pressure level of the n-pentane vapour in flash tank was about $110\~150\;kPa$ and that in the water tank was $93\~130\;kPa$. The pressure in the condenser during cycles was maintained as about 70 kPa. The condensation of the n-pentane vapour in the water tank was increased with the cycles even though the internal and external insulation were done. Air tank performance was better with increasing of the water piston displacement and the water could be pumped with the water piston displacement becoming higher than 6,500 cc.

• 설비공학논문집
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• 제24권5호
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• pp.391-400
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• 2012

In this study, performance of HFC32/HFC152a mixture is measured in the composition range of 20 to 50% R32 with an interval of 10% for the comparison with the conventional HCFC22 in water-source heat pumps. Tests are carried out under the same capacity in a heat pump bench tester equipped with a variable speed compressor at the evaporation and condensation temperatures of 7/$45^{\circ}C$ and -7/$41^{\circ}C$ for summer and winter conditions, respectively. Test results show that the compressor power of the HFC32/HFC152a mixture is 13.7% lower than that of HCFC22 while the coefficient of performance(COP) the HFC32/HFC152a mixture is 15.8% higher than that of HCFC22. Hence, from the view point of energy efficiency, the HFC32/HFC152a mixture is excellent as compared to HCFC22. Compressor discharge temperatures of HFC32/HFC152a mixture are increased up to $15.4^{\circ}C$ as compared to that of HCFC22. The amount of charge for HFC32/HFC152 mixture decrease up to 27% as compared to that of HCFC22. Overall, HFC32/ HFC152a mixture is an excellent long term candidate to replace HCFC22 in water-source heat pumps.