• 한국태양에너지학회:학술대회논문집
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• 한국태양에너지학회 2011년도 춘계학술발표대회 논문집
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• pp.156-161
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• 2011

In case of newly constructed buildings, the construction type is almost Curtain-wall system or large window in building skin. However, these kind of buildings have problems with regulations on building energy efficiency. And national regulations on building energy efficiency limit only the V-factor of window(except infiltration), it is hard to predict energy consumption of Curtain-wall buildings which gain large solar energy in summer. In this study, the influence of LSG(Light to Solar Gain) on energy performance was theoretically analyzed with simulation. LSG is the value of VLT divide SHGC and represents the optical performance of the glass or glazing. The Window & Therm program developed in LBNL was used to analyze window systems and EnergyPlus was used to building energy. Cases of glazing are three types; single coated Low-e clear glazing, tripple coated Low-e clear glazing, tripple coated Low-e tinted glazing. The results of this study are follows; 1) The building energy consumption of Alt-l, 2, 3 were about 300, 253, $259kWh/m^2{\cdot}yr$ respectively. Therefore, improvement of LSG could save the energy up to 16%. 2) The saved energy could be converted 1 billion won as annual benefit of total energy costs 3) SHGC and LSG more influence on cooling energy than heating energy in office buildings.

• 한국태양에너지학회 논문집
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• 제26권1호
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• pp.21-28
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• 2006

Changes in building construction methods and repairing of older buildings have reduced infiltration rate. Synthetic materials, release airborne particles and uneven healthy odor are increased. For preventing pollutants introduce fresh outdoor air into the building, simply letting fresh outdoor air into building, however, Is not a cost-effective way to ventilation. When additional ventilation is added to an existing HVAC system, the heating and cooling equipment, often cannot handle the increased load. A HRV provides a way to minimize in energy costs while introducing fresh air to a building. In this study, the economical research of HRV, made of three types of materials, are conducted. Heat recovering characteristics are studied at seasonal outdoor air conditions based on the outdoor air property condition at, Seoul in 2002. As a results, the average sensible effectiveness is 0.75 in the sensible heat exchanger and average total effectiveness is 0.65 in the total heat exchanger. The pay back period of the sensible heat exchangers are $3.2{\sim}3.5$ year and it of total heat exchanger is 2.2 years.

• Journal of Korean Dental Science
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• 제3권2호
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• pp.26-33
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• 2010

We searched at the "PubMed.gov" and "jendodon.com" sites to conduct a literature review on dental instruments that are reused in clinical settings and on infection control involving pre-disinfection or sterilization cleaning/rinsing. The keyword "dental clean" was used for the Web search. We found the present official definition of instrument cleaning performed prior to disinfection or sterilization rather limiting ("removal of foreign matter (soil, organism, etc.) from the instruments"). Thus, we proposed to expand the definition to include the removal of oils applied to protect the metallic instruments and from corrosion, stains, and rust resulting from the frequent reuse of the instruments. Clinicians are found to clean their dental instruments (a) immediately after treating their patients or (b) following their treatment but not immediately afterward. In the latter case, we recommend presoaking to be added. Ultrasonic sterilization of 5~15 minutes is found to be more effective in terms of eliminating residual matter from the instruments compared to other methods. To check on the cleaning results, we recommend visual inspection, which can be quick and practical in clinical settings. The latest products being developed and marketed on the market address the related problems. Nonetheless, research must be continued on the effects of presoak, cleaning/rinsing, disinfection, and high-temperature or heating-based sterilization on the dental instruments and on dental clinicians' practices in cleaning, disinfection, and sterilization. We advise dental clinicians to select the proper cleaning methods and detergents for their instruments to help eliminate or prevent corrosion, staining, and rusting, to reduce the maintenance costs, and to ensure user-friendly instruments/apparatuses.

• KIEAE Journal
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• 제9권1호
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• pp.107-113
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• 2009

The energy cost is resulted from the energy use. Its sources are divided into some types and depended on the building use or energy-use type. The energy cost should be affected by the amount of the energy use. The cost could be calculated to consider various factors such as the insulation, heating type, building shape and others. But it can not consider all of the affect factors to the energy cost and need to categorize the factors to the condition for estimating the cost. In this paper, it aimed at providing the estimation model in linear equation and multiple linear regression, utilizing the building exterior condition and management characteristics in apartment housing. Its survey are conducted in two parts of management characteristics and building exterior condition. The correlation analysis is conducted to get rid of the multicolinearity among the inputted factors. The number of linear equation model is 11 and includes the 1st, 2nd and 3rd equation function, power function and others. Among these, it suggested the 2nd and 3rd function and power function in terms of the statistics. In multiple linear regression model, the building volume and management area are inputted to the estimation.

• 한국농촌건축학회논문집
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• 제21권3호
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• pp.9-16
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• 2019

The increase in housing energy costs due to deteriorated rural house is directly related to the quality of life of rural residents, which is fundamental challenge for the government. In this study, we analyzed the current energy performance and the effect of housing energy efficiency improvement after remodeling of the four rural houses over 20 years old considering the rural housing type. As the result, the heating energy requirements of the unit surface is very high, and the effect was predicted to vary by housing after improved thermal insulation. This means that the cost of housing energy will be utilized as a target selection criterion or post-effect for the rural house remodeling project. In addition, the energy performance was analyze for the compact houses, which are in demand, mainly for young rural immigrants. As the result, the energy performance is very efficient.

• International Journal of Advanced Culture Technology
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• 제9권2호
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• pp.123-129
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• 2021

When shaving, it is easy to suffer shaving burns, that is, facial burn irritation during shaving. The reason is that the razor blade irritates the skin. The current solution is to make the razor sharper and use a razor with a blade heating function. Although these ways can increase the comfort of shaving, they will also greatly increase shaving costs. This paper proposes using a hairdryer to massage the skin before shaving to reduce skin irritation during shaving. This is a simple, practical and low-cost method. The hair dryer's heat, sound, and wind energy have a massage effect, and they can make shaving easier and more comfortable. For analyzing shaving effect, two evaluation methods are used, which are sound spectrum analysis and mos. The sound spectrum analysis is used to analyze the working status of the razor objectively. The MOS test can reflect the subjective feelings of the subject on the shaving's comfort. The results show that the hairdryer thermal vibration massage can make the beard easier to cut, thereby reducing the irritation of the razor to the skin and improving shaving comfort.

• 국제초고층학회논문집
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• 제12권2호
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• pp.107-120
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• 2023

Tall buildings are frequently decried as unsustainable due to their excessive energy usage. Early skyscrapers used natural light and ventilation to facilitate human comfort and applied organic materials such as stone, glass, wood, concrete, and terra cotta for cladding and finishes. With the advent of fluorescent lighting, modern heating, ventilation, air-conditioning (HVAC) systems, and thermally sealed curtain walls, tall office buildings no longer had to rely on natural light and ventilation to provide comfort. Energy efficiency was not a significant factor when the operational costs of buildings were relatively inexpensive. However, today's skyscrapers must become more energy-efficient and sustainable due to energy crises and climate change. This paper highlights vital energy-efficient design principles and demonstrates with illustrative case studies how they are applied to tall buildings in various parts of the world. It shows how sustainable environmental systems do not act alone but are integrated with advanced curtain wall systems, sky gardens, and atria, among others, to regulate and sustain thermal comfort and conserve energy.

• 설비공학논문집
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• 제21권12호
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• pp.715-732
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• 2009

This article reviews the papers published in the Korean Journal of Air-Conditioning and Refrigeration Engineering during 2008. It is intended to understand the status of current research in the areas of heating, cooling, ventilation, sanitation, and indoor environments of buildings and plant facilities. Conclusions are as follows. (1) Research trends in thermal and fluid engineering have been surveyed in the categories of general fluid flow, fluid machinery and piping, new and renewable energy, and fire. Well-developed CFD technologies were widely applied in developing facilities and their systems. New research topics include fire, fuel cell, and solar energy. Research was mainly focused on flow distribution and optimization in the fields of fluid machinery and piping. Topics related to the development of fans and compressors had been popular, but were no longer investigated widely. Research papers on micro heat exchangers using nanofluids and micro pumps were also not presented during this period. There were some studies on thermal reliability and performance in the fields of new and renewable energy. Numerical simulations of smoke ventilation and the spread of fire were the main topics in the field of fire. (2) Research works on heat transfer presented in 2008 have been reviewed in the categories of heat transfer characteristics, industrial heat exchangers, and ground heat exchangers. Research on heat transfer characteristics included thermal transport in cryogenic vessels, dish solar collectors, radiative thermal reflectors, variable conductance heat pipes, and flow condensation and evaporation of refrigerants. In the area of industrial heat exchangers, examined are research on micro-channel plate heat exchangers, liquid cooled cold plates, fin-tube heat exchangers, and frost behavior of heat exchanger fins. Measurements on ground thermal conductivity and on the thermal diffusion characteristics of ground heat exchangers were reported. (3) In the field of refrigeration, many studies were presented on simultaneous heating and cooling heat pump systems. Switching between various operation modes and optimizing the refrigerant charge were considered in this research. Studies of heat pump systems using unutilized energy sources such as sewage water and river water were reported. Evaporative cooling was studied both theoretically and experimentally as a potential alternative to the conventional methods. (4) Research papers on building facilities have been reviewed and divided into studies on heat and cold sources, air conditioning and air cleaning, ventilation, automatic control of heat sources with piping systems, and sound reduction in hydraulic turbine dynamo rooms. In particular, considered were efficient and effective uses of energy resulting in reduced environmental pollution and operating costs. (5) In the field of building environments, many studies focused on health and comfort. Ventilation. system performance was considered to be important in improving indoor air conditions. Due to high oil prices, various tests were planned to examine building energy consumption and to cut life cycle costs.

• Korean Chemical Engineering Research
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• 제56권1호
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• pp.6-13
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• 2018

석탄화력발전소 온배수열 활용하여 발전소 인근지역 시설농업에 난방열을 공급하는 사업의 배관투자비는 설치거리에 비례하여 증가하고 발전소와 떨어진 거리는 경제성 확보에 문제를 낳는다. 또한, 설치거리가 짧은 경우는 난방열 수요 확보가 어려워 경제성 확보의 문제가 있을 수 있다. 본 연구에서는 기준 열배관로 신설길이 1 km에 대한 경제성 평가와 열배관로 신설길이 변동에 따른 민감도를 정부지원금 수준, 난방열 수요량 수준과 정부지원금 증가에 따른 경제성 확보가능 열배관로 신설거리 수준에서 분석하였다. 분석결과 기준 열배관로 신설길이에서는 NPV 131백만원, IRR 15.73%로 경제성을 확보 가능한 것으로 평가되었다. 다만, 민감도 분석결과 열배관로 신설길이가 2.6 km를 초과하는 경우 NPV가 음수로 나타나 경제성을 확보하지 못하는 것으로 분석되었다. 결과적으로 초기투자비의 50%를 정부가 지원하는 경우 5.3 km, 80%를 지원하는 경우 11.4 km 이내에서 경제성을 확보하는 것으로 분석되었다. 기준 열배관로 신설길이에서는 난방열 수요가 기준 열수요 대비 62% 수준 이하로 감소하는 경우 경제성이 없으며, 열배관로 신설길이가 2 km에서는 기준 열수요 대비 14%만 감소하여도 경제성을 확보하지 못하는 것으로 분석되었다. 초기투자비대비 정부지원금 비율이 증가하는 경우 열배관로 신설거리의 탄력성이 증가하여, 열수요 1단위에서 부담하는 시설투자비인 고정비가 감소한다. 이는 단위당 생산원가가 감소하는 효과로 나타나고 시설농업에 더 저렴한 수준으로 열을 공급할 수 있음을 의미한다. 정부지원금은 열배관로 신설거리가 증가하는 효과로 경제성이 확보될 수 있고, 열수요 개발가능 범위 증가에 따라 추가적인 경제성을 확보할 수 있다. 초기투자비 대비 정부지원금 비율이 증가할수록 생산단가 감소로 인한 시설농가의 에너지비용 또한 감소할 것으로 예측된다. 본 연구결과는 발전소 온배수열 활용사업에 대한 정부지원금의 효과성을 경제적 평가측면에서 분석한 점에서 의의를 가지며, 향후 시범적용 또는 Pilot 단계의 실제 적용사례를 기반으로 한 경제성 평가결과에 대한 필요성을 제기할 수 있는 근거가 된다.

• 농업생명과학연구
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• 제46권2호
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• pp.179-190
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• 2012

본 연구는 유가상승에 따른 온실의 경영비 절감과 적설지역의 적설재해를 경감시키기 위하여 온수배관을 이용한 난방효과 및 온실곡부의 온도 상승효과를 구명하고자 수행되었다. 전체적으로 실험구의 온도가 대비구 보다 약 $2.0{\sim}6.0^{\circ}C$정도 높게 나타났다. 천창부직포를 개방한 경우, 최저온도가 약 $3.0{\sim}12.0^{\circ}C$범위로 나타나 적극적인 난방을 하게 되면 적설피해도 어느 정도 예방할 수 있을 것으로 판단되었다. 온실 내부의 높이별 온도 차이는 미미한 것으로 나타났다. 재배작물에 따른 온실의 최대난방부하는 각각 약 $37,000kcal{\cdot}h^{-1}$ 및 $41,700kcal{\cdot}h^{-1}$정도이었다. 실험기간동안 최저 외기온 $-11.9{\sim}4.0^{\circ}C$ 범위에서 설정온도별 발열량은 95,000~322,000 kcal 정도로서 시간당 $6,050{\sim}20,900kcal{\cdot}h^{-1}$정도의 범위에 있었고, 최대난방부하와 비교하면 약 15~56%정도의 난방에너지를 공급할 수 있을 것으로 나타났다. 그리고 실험기간동안 전체 발열량과 소비전력량은 각각 2,629,025 kcal 및 677.3 kWh이었다. 화석연료인 경유로 난방 할 경우, 실험기간동안 소요되는 소비량은 291L 정도이었고, 비용은 331,700 won인 것으로 나타났다. 전력사용에 대한 총비용은 24,400 won정도로서 경유 소비 비용의 7.5%정도로 나타났다. 또한 전체 소비전력량을 에너지로 환산하면 약 582,200 kcal이고, 이 에너지는 전체 발열량의 약 22%에 불과하였다.