대류난방시 상하온도차가 인체의 온열 쾌적성에 미치는 영향

김동규,김광호,김경철,박태안,박희욱 동의공업대학 2000 論文集 Vol.26 No.1

Purpose of this study is first to show the effects of vertical air temperature differences on thermal comfort and physiological responses, and second to examine the acceptable vertical air temperature differences. In this experiments, 12 subjects (6 males and 6 females) were exposed at 12 test conditions. The subjects voted each 10 min, about his thermal feeling, and 7 skin surface temperature, the air temperature were measured every 20 second. From this experiments, it was found that the upper part temperature affects the thermal sensation more strongly than lower part temperature. In winter, the acceptable temperature differences drawn by this study are 3℃ in the case that the upper part temperature is higher than the lower part temperature.

미활용에너지의 경제적 효과 및 보급지원방안 연구

안형준(An, Hyung-Jun),백성권(Baek, Sung-Kwon),허은녕(Heo, Eunn-Yeong) 한국신재생에너지학회 2008 한국신재생에너지학회 학술대회논문집 Vol.2008 No.05

Temperature difference energy is a good energy source replacing the fossil fuels. In the study, we classified the temperature difference energy as 4 types by the source & using method. For the understanding economic property of temperature difference energy, we tried simle economic analysis. As the result, Pay back period of 4 case of the temperature difference energy are from 1.23 to 12.65 years. Major factors influenced economic effect are operation time and energy user distance from the temperature difference energy source. If we can select optimal capacity and look for more effient energy users, Temperature difference energy play a important role of replacing fossil energy. So, for dess emination of temperature difference energy, we suggest that temperature difference energy must be included in renewable energy. Applying the effective methods among various promotion program of renewable energy policy, utilization of temperature difference energy could be activated.

미활용에너지의 경제적 효과 및 보급지원방안 연구

안형준,백성권,허은녕 한국자원공학회 2008 한국자원공학회지 Vol.45 No.4

Temperature difference energy is a good energy source replacing the fossil fuels. In this study, we classified the temperature difference energy as 4 types by the source & using method. For the understanding economic property of temperature difference energy, we tried simple economic analysis. As the result, Pay back period of 4 case of the temperature difference energy are from 1.23 to 12.65 years. Major factors influenced economic effect are operation time and distance from the temperature difference energy source to user. If we can select optimal capacity and look for more effient energy users, Temperature difference energy play a important role of replacing fossil energy. So, for dessemination of temperature difference energy, we suggest that temperature difference energy must be included in renewable energy. Applying the effective methods among various promotion program of renewable energy policy, utilization of temperature difference energy could be activated.

유기랭킨사이클에서 핀치온도차의 변화에 따른 열교환기의 열역학적 성능특성

김경훈,정영관,박상희 한국수소및신에너지학회 2015 한국수소 및 신에너지학회논문집 Vol.26 No.6

In this paper a performance analysis is carried out based on the first and second laws of thermodynamics for heat exchanger in organic Rankine cycle (ORC) for the recovery of low-temperature finite thermal energy source. In the analysis, effects of the selection of working fluid and pinch temperature difference are investigated on the performance of the heat exchanger including the effectiveness of the heat exchanger, exergy destruction, second-law efficiency, number of transfer unit (NTU), and pinch point. The temperature distribution are shown depending on the working fluids and the pinch temperature difference. The results show that the performance of the heat exchanger depends on the pinch temperature difference sensitively. As the pinch temperature increases, the exergy destruction in the evaporator increases but the effectiveness, second law efficiency and NTU decreases.

풍속과 일사량 변화에 따른 선형 아트리움의 자연환기량 변화 특성에 관한 연구

서명구(So, Myong Gu),김태연(Kim, Taeyeon),이승복(Leigh, Seung-Bok) 대한건축학회 2015 대한건축학회논문집 Vol.31 No.7

Atrium is a design element for the purpose of natural ventilation and natural lighting. In particular, it is possible to improve indoor thermal conditions and decrease energy usage load of a building through proper natural ventilation strategies. The natural ventilation can occur through temperature and pressure differences between the indoor and outdoor environment and across the atrium space. External wind speed and solar radiation influence the change of temperature differences and pressure differences significantly. However, it is difficult to analyze the exact nature of the wind speed and solar radiation and therefore natural ventilation rate as well. This study compares data from a CFD simulation model and actual data of an existing building to verify the validity of the simulation analysis. Then the natural ventilation rates of each temperature differences and pressure differences are analyzed using the CFD simulation. As a result, the increase in temperature differences increased the overall natural ventilation rate. However when there is an increase in external wind speed, the influence of solar radiation decreases and the temperature differences are also decreased. Temperature differences are the predominant influential factor until the external wind speed of 2.5m/s. After the wind speed of 2.5m/s, pressure differences are more influential factor than temperature differences. This study can be used as a basic material to provide operation strategies of atrium according to the seasonal outdoor conditions and to help setting the positions of openings in an atrium in design stage of a building construction.

내단열 콘크리트 외벽체의 실내 · 외 온도차에 따른 열저항 및 수렴성 분석

문지훈(Moon, Ji-Hoon),고명진(Ko, Myeong-Jin),최두성(Choi, Do-Sung),이예지(Lee, Ye-Ji),김용식(Kim, Yong-Shik) 대한건축학회 2022 대한건축학회논문집 Vol.38 No.11

Accurate diagnosis in the thermal performance of opaque walls through in-situ measurement is required in various fields. Many studies have tried to reduce the difference between the theoretical resistance using ISO 6946 and the thermal resistance using ISO 9869-1. There are many factors related to the accuracy of thermal performance, but the most important factor involves the temperature differences between the internal and external. This study aims to compare thermal resistance and convergence by selecting measurement periods with internal-external temperature differences of 28.4℃, 19.7℃, and 10.8℃. The study results showed that differences between the thermal resistances was -2.3% to 0.9%, which is similar to each other; three to five days of measurement fulfilled the convergence conditions of ISO 9869-1. If the stable outdoor environment and sufficient internal-external temperature differences are satisfied, it is possible to obtain thermal resistance with convergent properties that satisfy all of the convergence conditions regardless of the degree of internal-external temperature differences.

차압을 이용한 기밀성능 예측방법에서 실내외 온도차 및 건물 높이차의 의존성 검토

박승환(Seung Hwan Park),송두삼(Doo Sam Song) 대한설비공학회 2020 대한설비공학회 학술발표대회논문집 Vol.2020 No.6

The purpose of this paper is to examine the dependence on indoor and outdoor temperature difference and building height differences in the method of predicting the airtightness performance by using the differential pressure in high-rise buildings. In this study, in order to achieve this purpose, case study was conducted under the building condition with various floors and the condition of various outdoor temperature. The height difference of the building was similar to the measured value as the height of the building increased from the neutral zone. The indoor and outdoor temperature difference was similar to the measured value as the indoor and outdoor temperature difference increased. The predicted differential pressure condition similar to the measured value was predicted to be airtightness performance value similar to the measured value as the differential pressure increases, and is difficult to apply at low differential pressure. However, the method of predicting airtightness performance using pressure difference could be applied in various conditions because the high pressure difference can be formed in a high-rise residential buildings in winter.

플라스틱온실 피복재의 관류열전달계수 변화

이현우(Hyun-Woo Lee),소레이멘디옵(Souleymane Diop),김영식(Young-Shik Kim) (사)한국생물환경조절학회 2011 생물환경조절학회지 Vol.20 No.2

본 연구는 국내 상업용 온실 피복재의 관류열전달계수를 산정하는데 필요한 기초자료를 제공하기 위하여 최근 국내에 많이 보급되어 사용되고 있는 플라스틱필름으로 피복된 온실에 대해 관류열량을 측정하고 관류 열전달계수의 변화를 분석하였으며 그 결괴를 요약하면 다음과 같다. 온실 내외부 온도차에 따른 관류열전달계수의 변화를 분석한 결과 피복의 층수에 따라 안정된 관류열전달계수를 나타내게 되는 온실 내외부 온도차의 값이 다르게 나타났기 때문에 온실 피복재에 대한 관류열전달계수를 결정할 때에는 피복층수별로 안정된 값을 나타내는 온실 내외부 온도차 범위에서의 관류열전달계수를 채택하여야 할 것이다. 온도차이에 따른 관류열전달계수의 변화 경향은 기존의 연구결과와 잘 일치하였으나 안정된 값을 나타내는 온도차이의 구체적인 값은 다르게 나타났기 때문에 이에 대한 추가적인 연구가 필요할 것으로 판단된다. 풍속에 따른 관류열전달계수의 증가율은 연구자에 따라 많은 차이가 있음을 알 수 있었으며, 이중피복온실이나 커튼을 설치한 온실과 같이 보온성을 높인 온실은 일중피복온실에 비해 풍속에 따른 관류열 손실이 더 작다는 사실을 확인할 수 있었다. 관류열전달계수의 기존 연구결과들을 분석한 결과 연구지에 따라 값이 치이기 있었기 때문에 국내 온실의 정확한 난방부하량을 산정하는데 필요한 적절한 관류열전달계수를 제시하기 위해서는 우선 측정을 위한 표준화된 환경기준이 마련될 필요가 있으며, 또한 국내에서 실제로 시용되고 있는 주요 피복재별로 구체적인 관류열전달계수가 구해져야 할 것이다. The objective of the present study is to provide the basic data necessary for estimating the overall heat transfer coefficient of commercial plastic greenhouse. The heat flow through covering of greenhouses was measured and the variation of overall heat transfer coefficient was analyzed. Because the inside-outside temperature difference of greenhouse to indicate the stabilized overall heat transfer coefficient was different depending on the number of covering layers, the actual overall heat transfer coefficient should be decided in range of inside-outside temperature difference to make the coefficient constant for each covering method. The variation trend of the overall heat transfer coefficient according to the inside-outside temperature difference corresponded with the existing research results, but the specific values of temperature difference to present the stabilized overall heat transfer coefficient were different each other. The increase rates of overall heat transfer coefficient with wind speed were quite dissimilar among several research results and the quantity of heat loss through covering according to the wind speed in the double layers covered or curtained greenhouse was less than that in the single layer covered greenhouse. Because there was large variations among the values of overall heat transfer coefficient for the polyethylene film greenhouses, it was required to establish the standardized environmental condition for experiment measuring heat flow through covering in commercial greenhouse.

온도차에너지의 농어촌 활용을 위한 이용 가능량 및 법제도 분석

김진욱(Jinwook Kim),류연수(Yeonsu Ryoo),박미란(Milan Park) 한국신재생에너지학회 2015 신재생에너지 Vol.11 No.3

There is an ever-growing interest in alternative energy sources, and more and more technologies are becoming viable options as efforts to reduce greenhouse gas production and fossil fuel consumption increase. Unutilized energy has been attracting particular attention as a community based alternative energy source. Temperature difference energy is ubiquitous in nature, and it may be possible to harvest this energy without any significant influence on the local environment. In this study, we examined reserves and available capacity of temperature difference energy sources(treated sewage, river water, and an agricultural reservoir) for the supply of energy to a rural community. Reserves and available capacity of treated sewage were 6,555 Tcal/yr and, 4,318 Tcal/yr, respectively, while reserves and available capacity of river water were 192,000 Tcal/yr and 1,632 Tcal/yr, respectively. Agricultural reservoirs returned reserve and available capacity figures of 7,994 Tcal/yr and 141 Tcal/yr, respectively. In addition, we presented a review of legal and systematic considerations which might pave the way for larger scale temperature difference projects in the future. We also suggest a direction for future temperature difference energy based on the current Korean legal system.

콘크리트 슬래브가 없는 강재주형에서 상하연 온도차에 대한 실측연구

신동욱,김경남,정경섭,이성행 한국구조물진단유지관리공학회 2014 한국구조물진단유지관리공학회 논문집 Vol.18 No.4

합리적인 온도 설계하중을 연구하기 위하여, 실제 크기의 콘크리트 슬래브가 없는 강상형 거더 교량 시험체를 제작하였다. 높이에 따라 부착된 18개의 온도 게이지에서 5개월 동안 온도 데이터를 측정하였다. 강상형 거더 교량 시험체의 상단과 하단 사이의 온도 차가 계산되고, 온도 구배 모형이 확률 방법으로 제안되었다. 본 연구에서 제시된 모형은 유로 코드에 의해 제안 된 모델과 비교했을 때 약 97%의 상관관계를 보인다. 따라서, 본 연구의 결과로 제안 된 온도 구배 모델은 온도 설계 하중 계산시 기초 자료로 활용 될 수 있다. In order to study the reasonable design thermal loads, the steel box girder bridge specimen which have no concrete slab was manufactured with the real size dimension. The temperature data were measured for 5 month at the 18 thermo gauges which were attached according to height. The temperature differences between the top and bottom flange in steel box girder specimen were calculated and the temperature gradient models were proposed by the probabilistic method. This proposed model showed a correlation of approximately 97% when compared with the similar model of Euro Code. Thus, the temperature gradient models which were suggested in this study may be used as the basis data in calculating the design load temperature.