• Title/Summary/Keyword: Thermal-Comfort

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Thermal Comfort and Sleep under Different Room Temperatures (침상내 기후와 수면과의 관계)

  • Lee Young Suk;Engel Peter
    • Journal of the Korean Society of Clothing and Textiles
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    • v.15 no.4 s.40
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    • pp.351-365
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    • 1991
  • 본 연구에서는, 수면환경의 열적 쾌적도의 측정방법으로서 생리적 반응 뿐만 아닌 국소자극의 반응에 대한 평가법 (Allesthesial Response)에 의 한 가능성을 제시 하고자 하였다. 피험자는 19세에서 22세의 건강한 독일 여자 대학생 5명이며, 실험은 12월과 1월 독일의 KASSEL에 있는 Marburg대학 연구소의 인공기후실에서 이루어졌다. 사용의복은 면 $100\%$의 잠옷이며, 침구는 메트리스와 Wool 담요(두께 180 mm)를 사용하였다. 국소자극 반응의 온도는 $20.0^{\circ}C,\;22.5^{\circ}C,\;25.0^{\circ}C,\;27.5^{\circ}C,\;30.0^{\circ}C,\;32.5^{\circ}C$의 set가 사용되었으며, 온도자극은 Pottier Thermode type PKE 36 HO2-1 (독일, Peltroil사)로서, 온도의 도달정 밀도는 60내지 90초 동안에 각 자극온도의 변화조절이 가능하였다. 수면환경 온도는 $15^{\circ}C,\;18^{\circ}C,\;21^{\circ}C,\;24^{\circ}C,\;27^{\circ}C$의 다섯 환경으로 조절하였으며, 습도는 RH $45\%$였다. 수면환경 $18^{\circ}C$에서 $24^{\circ}C$까지에서는, 수면전, 수면후 모두, 피험자는 약간의 Hypothermia의 경향을 보였지만 Neutral Situation과 큰 차이는 나타나지 않았다. 수면전과 수면후의 체온조절 반응의 차이가 Allesthesial Response와 국소의 쾌적한 온도 선택의 두 실험결과 모두에서 현저히 나타났다. 생리적 반응의 결과에서도 $18^{\circ}C$에서 $21^{\circ}C$까지의 수면환경이 가장 쾌적하게 나타났다. 또한, 실험결과에서 행동적 온도 조절 반응이 생리적 반응에 앞서 보다 민감하게 이루어짐을 볼 수 있었다

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The Relationship between Increased Cold Tolerance Resulting from Cool Clothing on Heat Tolerance (의복을 이용한 내한성 향상 훈련이 내열성에 미치는 영향)

  • 이종민
    • Journal of the Korean Society of Clothing and Textiles
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    • v.21 no.4
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    • pp.669-676
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    • 1997
  • The purpose of this study is to examine the effect of the improved cold tolerance resulting from cool clothing in winter on heat tolerance in summer. Ten healthy women were divided into two groups, cold group(C group) (n=5) and warm group(W group) (n=5) . In the previous study, C group was proved that their cold acclimatization was achieved through wearing cool clothing from September to February of the following year, while Wgroup was not proved because of wearing warm clothing during same period. After February, no more clothing training was continued in two groups. To determine the heat tolerance, both groups were exposed from a thermoneutral environment(25$\pm$1$^{\circ}C$, 50$\pm$5% R.H.) to a hot environment (35$\pm$1$^{\circ}C$, 50$\pm$5% R.H.) before and after clothing training, respectively September in 1994 and truly in 1995. Rectal temperature, skin temperatures, thermal sensation and comfort were measured every 10 min., and Os uptake was measured at 10, 45, 85 min. after entering the chamber for 5 min. Body weight was measured before and after the experiment and amount of local sweat was measured during the 90 min long experiment. The results are as follows: Rectal temperatures in 35'c environment of C group were increased after training when compared with before clothing, while those of W group were not changed. But the changes of rectal temperature and heat production during 90 min in hot environment were almost the same in two groups after training. And mean skin temperatures, the changes of mean skin temperatures during 90 min in hot environment, total sweat amount and local sweat amount after training were also the same in two groups. From these results, it might be supposed that the heat loss of two groups were the same but the heat production, especially heat production during rest in C group was higher than in Wgroup. This fact suggests that the increase of rest heat production from cold acclimatization in winter is maintained to summer of the following year. And mild cold acclimatization coming from westing cool clothing does not have a negative effect on heat tolerance.

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Ventilation Hole Optimum Design of Smart Unit Load Container for Storage and Distribution Agricultural Products by Theoretical Heat Flow Analysis (이론적 열유동 해석을 이용한 농산물 저장 및 유통 스마트 유닛로드 컨테이너의 통기공 최적화 설계)

  • Dong-Soo, Choi;Yong-Hoon, Kim;Jin-SE, Kim;Chun-Wan, Park;Hyun-Mo, Jung;Ghi-Seok, Kim;Jong-Min, Park
    • KOREAN JOURNAL OF PACKAGING SCIENCE & TECHNOLOGY
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    • v.28 no.3
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    • pp.211-215
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    • 2022
  • Air distribution occupies an important position in the smart unit load container design process for agricultural products. Inner air may be uncomfortable because of its temperature, speed, direction, and volume flow rate. It doesn't matter how efficient the ventilation equipment is if the air is not distributed well. The main aim of this study was to design the inlet and outlet fan locations of smart unit load container for agricultural products. A numerical study was performed on the effects of the location of inlet air and outlet air in relation to the container cooling sources on air distribution and thermal comfort. A concept of combining inner container cooling sources with the exhaust outlet was employed in this investigation. Also, in this research, the developed CFD (Computational Fluid Dynamics) models were thoroughly validated. This system was adopted for use in container spaces, where the exhaust outlet was located. In this study, the location of the inlet was derived through CFD for a container with a size of 1,100×1,100×1,700 mm, and it was derived that the inlet was located at the center of the lower part of the container for efficient air flow. It was efficient to position the outlet through the air inlet in the center of the lower part of the container at the top of the same side.

Effect of Ventilation on Heat Stress in the System of Short-Sleeve T-Shirt-Combat Uniform-Chemical, Biological, and Radioactive Protective Clothing (반팔 내의-전투복-화생방보호의 시스템에서 환기가 열적 스트레스에 미치는 영향)

  • Lee, Okkyung;Eom, Rani;Jung, Heesoo;Cho, Kyeong Min;Lee, Yejin
    • Journal of the Korean Society of Clothing and Textiles
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    • v.46 no.5
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    • pp.836-847
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    • 2022
  • This study establishes basic data for the development of a new Chemical, Biological, and Radioactive (CBR) protective clothing by selecting the ventilation position to optimize thermal comfort on the basis of the opening and closing of each part. Participants were eight men in their 20s who had previously worn CBR protective clothing. After vigorous exercise and perspiration, the microclimate of the clothing and skin temperature was measured. Results revealed that when the ventilation zipper was opened after exercising, the skin and clothing microclimate temperatures, which had increased during the exercise, decreased in the chest and shoulder blade regions. The clothing microclimate humidity decreased in the chest area. The change was greatest in the chest region; the skin temperature decreased by 0.2℃, the clothing microclimate temperature by 2.7℃, and the clothing microclimate humidity by 3.2%RH through ventilation. Thus, the opening that allows the exchange of accumulated heat and moisture while wearing the CBR protective clothing is efficient.

Development and evaluation of women's leggings prototype for improvement of blood circulation through flexible heating surface and gradual compression (점진적 컴프레션 및 유연면상발열을 통한 혈액순환 개선 여성 레깅스 프로토타입 개발 및 평가)

  • Jin Hee Hwang;Yun Ah Lee;Seung Hyun Jee;Sun Hee Kim
    • Journal of the Korea Fashion and Costume Design Association
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    • v.25 no.3
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    • pp.53-67
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    • 2023
  • Blood circulation is one of the most important life support functions of our body. It is essential to maintain healthy blood circulation as problems with blood circulation can lead to numerous diseases and serious complications. This study developed women's leggings with gradual compression and soft surface heating functions to improve blood circulation, and evaluated their performance and wearability. A silicon print pattern was developed to provide gradual compression, and a flexible heating surface coated with MWCNT (multi-walled carbon nanotube) conductive ink was fabricated for comfort and thermal effect. For the design, incision lines and materials were applied in consideration of aesthetic aspects, and design lines and colors were altered using a 3D program. The developed leggings showed that blood circulation can be improved when gradual compression and heating functions are simultaneously applied. Results were confirmed through measurements of clothing pressure, blood flow, and surface temperature. In the subjective wearability evaluation, it was confirmed that wearers felt gradual pressure, and they showed high satisfaction with wearability and design.

Recent Progress in Air Conditioning and Refrigeration Research - A Review of papers Published in the Korean Journal of Air-Conditioning and Refrigeration Engineering in 1998 and 1999 - (공기조화, 냉동 분야의 최근 연구 동향 - 1998년 1999년 학회지 논문에 대한 종합적 고찰 -)

  • 이재헌;김광우;김병주;이재효;김우승;조형희;김민수
    • Korean Journal of Air-Conditioning and Refrigeration Engineering
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    • v.12 no.12
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    • pp.1098-1125
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    • 2000
  • A review on the papers published in the Korean Journal of Air-Conditioning and Refrigerating Engineering in 1998 and 1999 has been done. Focus has been put on current status of research in the aspect of heating, cooling, ventilation, sanitation and building environment. The conclusions are as follows. 1) A review of the recent studies on fluid flow, turbomachinery and pipe-network shows that many experimental investigations are conducted in applications of impingement jets. Researches on turbulent flows, pipe flows, pipe-networks are focused on analyses of practical systems and prediction of system performance. The results of noise reduction in the turbomachinery are also reported. 2) A review of the recent studies on heat transfer analysis and heat exchanger shows that there were many papers on the channel flow with the application to the design of heat exchanger in the heat transfer analysis. Various experimental and numerical papers on heat exchanger were also published, however, there were few papers available for the analysis of whole system including heat exchanger. 3) A review of the recent studies on heat pump system have focused on the multi-type system and the heat pump cycle to utilize treated sewage as the heat source. The defrosting and the frosting behaviors in the fin-tube heat exchanger is experimentally examined by several authors. Several papers on the ice storage cooling system are presented to show the dynamic simulation program and optimal operation conditions. The study on the micro heat pipes for the cooling of high power electronic components is carried out to examine the characteristics of heat and mass transfer processed. In addition to these, new type of separate thermosyphon is studied experimentally. 4) The recent studies on refrigeration/air conditioning system have focused on the system performance and efficiency for new alternative refrigerants. New systems operating with natural refrigerants are drawing lots of attention. In addition to these, evaporation and condensation heat transfer characteristics of traditional and new refrigerants are investigated for plain tubes and also for microfin tubes. Capillary tubes and orifice are main topics of research as expansion devices and studies on thermophysical properties of new refrigerants and refrigerant/oil mixtures are widely carried out. 5) A review of the recent studies on absorption cooling system shows that numerous experimental and analytical studies on the improvement of absorber performance have been presented. Dynamic analysis of compressor have been performed to understand its vibration characteristics. However research works on tow-phase flow and heat transfer, which could be encountered in the refrigeration system and various phase-change heat exchanger, were seemed to be insufficient. 6) A review of recent studies on duct system shows that the methods for circuit analysis, and flow balancing have been presented. Researches on ventilation are focused on the measurement of ventilation efficiency, and variation of ventilation efficiency with ventilation methods by numerous experimental and numerical studies. Furthermore, many studies have been conducted in real building in order to estimate indoor thermal environments. Many research works to get some information for cooling tower design have been performed but are insufficient. 7) A review on the recent studies on architectural thermal environment and building mechanical systems design shows that thermal comfort analysis is sitting environment, thermal performance analysis of Korean traditional building structures., and evaluation of building environmental load have been performed. However research works to improve the performance of mechanical system design and construction technology were seemed to be insufficient.

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Analysis of Microclimate Impact According to Development Scenarios of Vacant Land in Downtown Seoul - A Comparison of Wind Speed and Air Temperature - (서울 도심 공지의 개발 시나리오에 따른 미기후 영향 분석 - 풍속 및 기온 비교 -)

  • Baek, Jiwon;Park, Chan;Park, Somin;Choi, Jaeyeon;Song, Wonkyong;Kang, Dain;Kim, Suryeon
    • Journal of Environmental Impact Assessment
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    • v.30 no.2
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    • pp.105-116
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    • 2021
  • In the city of high population density crowded with buildings, Urban Heat Island (UHI) is intensified, and the city is vulnerable to thermal comfort. The maintenance of vacant land in downtown is treated as a factor that undermines the residential environment, spoils the urban landscape, and decreases the economic vitality of the whole region. Therefore, this study compared the effects on microclimate in the surrounding area according to the development scenarios targeting the vacant land in Songhyeon-dong, Jongno-gu, Seoul. The status quo, green oriented, building oriented and green-building mediation scenarios were established and ENVI-met was used to compare and analyze the impact of changes in wind speed, air temperature and mean radiant temperature (MRT) within 1 km of the target and the target site. The result of inside and 1 km radius the targeted area showed that the seasonal average temperature decreased and the wind speed increased when the green oriented scenario was compared with the current state one. It was expected that the temperature lowered to -0.73 ℃ or increased to 1.5 ℃ in summer, and the wind speed was affected up to 210 meters depending on the scenario. And it was revealed that green area inside the site generally affects inside area, but the layout and size of the buildings affect either internal and external area. This study is expected to help as a decision-making support tool for developing Songhyeon-dong area and to be used to reflect the part related to microclimate on the future environmental effects evaluation system.

Effect of Wear Training on Temperature Adaptability of the Obese Children (비만아동의 온도적응성에 대한 착의훈련 효과)

  • Jeong, Woon-Seon
    • Journal of the Korean Society of Clothing and Textiles
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    • v.30 no.3 s.151
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    • pp.407-411
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    • 2006
  • This study was carried out to investigate the physiological responses of obese children after a short-term wear training and education. A ten-week program was conducted on thirteen obese elementary school children of six boys and seven girls in the 4th to the 6th grade. During the program, the children were instructed to measure daily ambient temperature and weight of their clothing. Physiological responses of the sedentary children in 100$\%$ cotton short sleeved t-shirt (0.13clo) and T/C short pants(0.09clo) were observed in the climatic chamber of 23.0$\pm$0.5$^{circ}C$ and 50$\pm$5$\%$RH before and after program. During the experiment, internal ear temperature ($T_{ear}$), seven site skin temperatures, systolic blood pressure, diastolic blood pressure, heart rate, and subjective responses of thermal comfort and thermal sensation were measured every 5minutes. Mean skin temperature($T_{sk}$) and mean arterial pressure(MAP) were calculated. Obtained data are statistically analyzed and main results are as follows. There was highly significant correlation between the ambient temperature and the total clothing weight. $T_{ear}$ and MAP were reduced in the post-program compared to the pre-program. The obese girls felt slightly warmer than the obese boys and the girls were likely to prefer lower ambient temperature in the post-program than the pre-program. It was concluded that the 10 week wear training is apt to be more applicable to the obese girls than the obese boys. However, a more comprehensive study including. diverse measurements of deep body temperature with a long-term training would be needed to clarify the improvement of temperature adaptability in the obese children.

A Study of the Urban Tree Canopy Mean Radiant Temperature Mitigation Estimation (도시림의 여름철 평균복사온도 저감 추정 연구)

  • An, Seung Man;Son, Hak-gi;Lee, Kyoo-Seock;Yi, Chaeyeon
    • Journal of the Korean Institute of Landscape Architecture
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    • v.44 no.1
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    • pp.93-106
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    • 2016
  • This study aimed to estimate and evaluate the thermal mitigation of the urban tree canopy on the summer outdoor environment by quantitative use of mean radiant temperature. This study applied the SOLWEIG model based $T_{mrt}$ comparison method by using both (1) urban tree canopy presence examples and (2) urban tree canopy absence examples as constructed from airborne LiDAR system based three-dimensional point cloud data. As a result, it was found that an urban tree canopy can provide a decrease in the entire domain averaged daily mean $T_{mrt}$ about $5^{\circ}C$ and that the difference can increase up to $33^{\circ}C$ depending both on sun position and site conditions. These results will enhance urban microclimate studies such as indices (e.g., wind speed, humidity, air temperature) and biometeorology (e.g., perceived temperature) and will be used to support forest based public green policy development.

A field Study to Evaluate Cooling Effects of Green Facade under Different Irrigation Conditions - Focusing on modular green facade planted with Hedera helix L and Pachysandra terminalis - (관수조절에 의한 벽면녹화의 냉각효과 분석 연구- 아이비, 수호초를 식재한 모듈형 벽면녹화를 중심으로-)

  • Kim, Eun-Sub;Yun, Seok-Hwan;Piao, Zheng-gang;Jeon, Yoon-Ho;Kang, Hye-Won;Kim, Sang-Hyuck;Kim, Ji-Yeon;Lee, Young-Gu;Lee, Dong-Kun
    • Journal of the Korean Society of Environmental Restoration Technology
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    • v.24 no.6
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    • pp.121-132
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    • 2021
  • Green facade has a significant impact on building's energy performance by controlling the absorption of solar radiation and improving outdoor thermal comfort through shading and evapotranspiration. In particular, since high-density building does not enough green space, green facade, and rooftop greening using artificial ground plants are highly utilized. However, the level of cooling effect according to plant traits and irrigation control is different. Therefore, in this study, the cooling effect analyzed for a total of 4 cases by controlling the irrigation condition based on hedera and spurge. Although hedera under sufficient water had the highest cooling effect(-2℃~-4℃), had the lowest cooling effect under non-irrigation(+1.1℃~+4.4℃). In addition, hedera under sufficient water had cooling effect than hedera under non-irrigation(-1℃~-8.1℃) and in the case of spurge, it had cooling effect(-0.3℃~-7.8℃) more than non-irrigation. As a result of measuring the amount of transpiration according to the light intensity (PAR) and carbon dioxide concentration conditions, transpiration of hedera was higher than the spurge (respectively 0.63204mmolm-2s-1, 0.674367mmolm-2s-1). The difference in the cooling effect of the green facade under irrigation condition was significant. But the potential cooling effect of green facade according to plants species was different. Therefore, in order to maximize and continuously provide the cooling effect of green facade in urban areas, it is necessary to consider the characteristics of plants and the control of water supply through the irrigation system.