• Title/Summary/Keyword: Thermal Comfort Temperature

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Analysis of Surface Temperature Characteristics by Land Surface Fabrics Using UAV TIR Images (UAV 열적외 영상을 활용한 피복재질별 표면온도 특성 분석)

  • SONG, Bong-Geun;KIM, Gyeong-Ah;SEO, Kyeong-Ho;LEE, Seung-Won;PARK, Kyung-Hun
    • Journal of the Korean Association of Geographic Information Studies
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    • v.21 no.3
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    • pp.162-175
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    • 2018
  • The purpose of this study was to analyze the surface temperature of surface fabrics using UAV TIR images, to mitigate problems in the thermal environment of urban areas. Surface temperature values derived from UAV images were compared with those measured in-situ during the similar period as when the images were taken. The difference in the in-situ measured and UAV image derived surface temperatures is the highest for gray colored concrete roof fabrics, at $17^{\circ}C$, and urethane fabrics show the lowest difference, at $0.3^{\circ}C$. The experiment power of the scatter plot of in-situ measured and UAV image derived surface temperatures was 63.75%, indicating that the correlation between the two is high. The surface fabrics with high temperature are metal roofs($48.9^{\circ}C$), urethane($43.4^{\circ}C$), and gray colored concrete roofs($42.9^{\circ}C$), and those with low temperature are barren land($30.2^{\circ}C$), area with trees and lawns($30.2^{\circ}C$), and white colored concrete roofs($34.9^{\circ}C$). These results show that accurate analysis of the thermal characteristics of surface fabrics is possible using UAV images. In future, it will be necessary to increase the usability of UAV images via comparison with in-situ data and linkage to satellite imagery.

Relationships between Insensible Perspiration and Thermo Physiological Factors during Wearing Seasonal Clothing Ensembles in Comfort (쾌적한 상태에서 계절별 의복을 착용하고 있는 동안 불감증설과 온열 생리 요소들 간의 관련성)

  • Lee, Joo-Young;Choi, Jeong-Wha;Park, Joon-Hee
    • Journal of the Korean Society of Clothing and Textiles
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    • v.31 no.12
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    • pp.1700-1709
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    • 2007
  • The purpose of this study was to examine the relationships between thermo-physiological factors and the insensible loss of body weight(IL) of resting women wearing seasonal comfortable clothing. Air temperature was maintained at a mean of 22.5, 24.7, and 16.8 for spring/fall, summer and winter, respectively. We selected a total of 26 clothing ensembles(8 ensembles for spring/fall, 7 ensembles for summer, and 11 ensembles for winter). The results showed that 1) IL was $19{\pm}5g{\cdot}m^{-2}{\cdot}hr$ for spring/fall environment, $21{\pm}5g{\cdot}m^{-2}{\cdot}hr$ for summer, $18{\pm}6{\cdot}m^{-2}{\cdot}hr$ for winter(p<.001). 2) Insensible water loss through respiratory passage(IWR) showed the reverse tendency to IL. IWR was $6{\pm}1g{\cdot}m^{-2}{\cdot}hr$ for winter and $5{\pm}1g{\cdot}m^{-2}{\cdot}hr$ for summer. This difference was significant(p<.001). 3) The proportion of IWR out of whole insensible water loss(IW), had a mean of the mean 28% for summer and 38% for winter(p<.001). 4) In comfort, the heat loss by IW out of heat production had a mean of 25% for spring/fall, 27% for summer, and 23% for winter. 5) There was a weak negative correlation between It and clothing insulation/body surface area covered by clothing. 6) There were significant correlations between IL and air temperature$(T_a)$, air humidity$(H_a)$, energy metabolism, ventilation, mean skin temperature $\={T}_{sk})$ and clothing microclimate humidity$(H_{clo})$. However, the coefficients were less than 0.5. In conclusion, there were weak relationships between the IL and thermo-physiological factors. However, when subjects rested in thermal comfort, the IL was maintained in a narrow range even though the clothing insulation and air temperature were diverse.

An Experimental Study of the Bioelectrical Signals and Subjective Response in Changing from Unpleasant to Pleasant Temperatures in a Learning Environment (학습환경에서 불쾌적온도에서 쾌적온도로의 변화시 생체신호 및 주관적 반응에 대한 실험적 연구)

  • Im, Gwanghyun;Kim, Jinhyun;Park, Chasik;Cho, Honghyun
    • Korean Journal of Air-Conditioning and Refrigeration Engineering
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    • v.27 no.11
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    • pp.596-602
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    • 2015
  • In this study, experiments using bioelectronic signals and questionnaire surveys were carried out in learning conditions when temperatures changed from low- and high-uncomfortable to comfortable. As a result, the stress factor Photoplethysmography (PPG) decreased, while the Root Mean Square of Standard Deviation (RMSSD) of PPG increased when the indoor temperature was changed from low- or high-uncomfortable to comfortable. Additionally, the absolute power of the ${\alpha}$-wave in the brain increased. According to the analysis of the association between the questionnaire and bioelectronic signals, the standard deviation of the stress factor as measured by pulse was closely related to the result of the thermal sensation questionnaire. In addition, it was found that the concentration on studying improved under comfortable temperatures when compared to uncomfortable temperatures.

A Study on the Wearing Comfort of Firefighter's Protective Clothing (한국 소방방수피복의 착용만족도 및 개선방안에 관한 조사연구)

  • Chung Jung-Sook;Lee Youn-Soon
    • Journal of the Korean Home Economics Association
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    • v.37 no.12 s.142
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    • pp.59-67
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    • 1999
  • This study analyzed firefighter's actual wearing condition of turnout gear The results are as fellows: 1. When a firefighter is employed, Korea applies only the minimum of firefighters stature and weight but America applies both the minimum and the maximum. The choice of size is highly related with stature more than chest circumference. 2. The satisfaction degree of thermal barrier is very low, 3%. They used rubber gloves rather than heatproof gloves. This is more serious in small country like 'up', 'myun' than in cities. For laundering, they used sprinkling method with firefighting hose. Firefigthers hoped that their clothes could be classified tv the seasons and fire places. 3. frefighter had high unsatisfaction with the movement of hands and leges in the aspect of movement adjustability, air permeability, weight, body temperature regulation, and breathing in the hygenic aspect, fire resistance, thermal resistance property, water proof, chemical reactivity and electrical conductivity. Thev were also unsatisfied with water proof boots and gloves. They were generally satisfied with helmets but firefighters over 90kg of weight were rather unsatisfied. 4. The satisfaction degree for physical fitness was very low and the items with which they were not satisfied depend on physical features. 5. To develop turnout gear, they wanted changes in design, material and size. Reflection tape need to be replaced with high quality products and they wanted the use of velcro and zipper in fastening system.

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Analysis of Teenagers' Self-identified Cold Tolerance and Wearing Behavior Inside and Outside the Classroom During Winter (청소년들의 겨울철 교실 내·외 환경에서의 자각적 내한성과 착의행동 분석)

  • Hong, Min-Hyun;Son, Su-Young
    • Journal of the Korean Society of Clothing and Textiles
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    • v.44 no.1
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    • pp.126-140
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    • 2020
  • This study analyzed the self-identified cold tolerance and wearing behavior of teenagers inside and outside the classroom during winter, considering recent climate changes. A questionnaire was divided into four parts-general information, thermal and comfort sensation inside and outside classroom, self-identified cold tolerance, and wearing behavior to collect data from 322 students. Over several years, changes were noted in respondents' wearing behavior during winter outings, with the biggest being the purchase of a "long padded jacket" for warmth while outside. Most respondents showed similar wearing behavior, such as no difference between the number of clothes worn in a classroom maintained at 20℃ (girls: 8.0±3.1 layer, boys: 6.5±2.1 layer) and outside (girls: 8.8±3.4 layer, boys: 7.1±3.0 layer), despite feeling differently about the thermal sensation inside and outside the classroom. This difference may due to a teenager's lack of knowledge about temperature and their tendency to follow clothing trends. Female students were more sensitive to the cold and wore more garments inside and outside the classroom. Gender-related differences should be considered when educating teenagers about safe and healthy clothing.

Green-infra Strategies for Mitigating Urban Heat Island (도시열섬현상완화를 위한 그린인프라 전략)

  • Park, Chae-Yeon;Lee, Dong-Kun;Kwon, Eu-gene;Her, Min-ju
    • Journal of the Korean Society of Environmental Restoration Technology
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    • v.20 no.5
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    • pp.67-81
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    • 2017
  • Because of lack of accurate understanding of the mechanism of urban heat island (UHI) phenomenon and lack of scientific discussion, it is hard to come up with effective measures to mitigate UHI phenomenon. This study systematically described the UHI and suggested the solutions using green-infrastructure (green-infra). The factors that control UHI are very diverse: radiant heat flux, latent heat flux, storage heat flux, and artificial heat flux, and the air temperature is formed by the combination effect of radiation, conduction and convection. Green-infra strategies can improve thermal environment by reducing radiant heat flux (the albedo effect, the shade effect), increasing latent heat flux (the evapotranspiration effect), and creating a wind path (cooling air flow). As a result of measurement, green-infra could reduce radiant heat flux as $270W/m^2$ due to shadow effect and produce $170W/m^2$ latent heat flux due to evaporation. Finally, green-infra can be applied differently on the macro(urban) scale and micro scale, therefore, we should plan and design green-infra after the target objects of structures are set.

Experimental study on thermal comfort sensation and physiological responses of Koreans in various thermal conditions Part III : The effects of vertical air temperature difference in a room (한국인의 온열쾌적감 및 생리신호에 관한 연구 (Part III: 상하온도차에 관한 실험 결과))

  • 김동규;배동석;금종수;최광환;김성일;임금식;이구형
    • Proceedings of the Korean Society for Emotion and Sensibility Conference
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    • 1998.04a
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    • pp.264-269
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    • 1998
  • 본 연구에서는 겨울철 대류 난방시 발생하기 쉬운 실내 기온의 상하분포가 인체에 미치는 영향에 관하여 청년층의 피험자를 대상으로 한 체감실험을 수행하여 인체의 생리 및 심리반응에 미치는 영향을 검토하였다. 체감 실험 결과 아래와 같은 결론을 얻었다. 1) 머리부위 공기온도가 23$^{\circ}C$ 인 경우 두한족열의 경우가 두열족한의 경우에 비하여 전신온냉감 및 쾌불쾌감이 양호한 것으로 나타났다. 2)두열족한의 경우 발 부위가 서늘하다는 비율은 상하온도차가 증가($\Delta$t 3$^{\circ}C$ ->6$^{\circ}C$)하면 역시 증가하였고, 두한족열의 경우 머리 부위 온도 23$^{\circ}C$에서는 발부위온도를 증가시키면($\Delta$t 3$^{\circ}C$->6$^{\circ}C$)불쾌 비율이 증가하는 경향을 나타냈다. 3) 신체 부위별 온열감과의 관계를 보면 어깨부위에서 느끼는 온열감이 전반적으로 쾌불쾌감 및 전신온냉감과 유의차를 나타냈다. 얼굴 부위에서의 온열감은 머리부위 공기온도 $25^{\circ}C$이상에서 쾌불쾌감과 유의차를 나타냈고, 발 부위에서의 온열감은 머리부위 공기온도 $25^{\circ}C$ 이하에서 전신온냉감과 유의차를 나타냈다.

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Prediction of Latent Heat Load Reduction Effect of the Dehumidifying Air-Conditioning System with Membrane (분리막 제습공조시스템의 잠열부하 저감효과 예측)

  • Jung, Yong-Ho;Park, Seong-Ryong
    • Korean Journal of Air-Conditioning and Refrigeration Engineering
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    • v.29 no.1
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    • pp.15-20
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    • 2017
  • The summer climate is very hot and humid in Korea. The humidity is an important factor in determining thermal comfort. Recently, the research for dehumidification device development has been attempted to save energy that is required for the operation of the current dehumidifiers on the market. Existing dehumidification systems have disadvantages such as wasting energy to drive a compressor. Meanwhile, dehumidification systems with membranes can dehumidify humid air without increasing the dry bulb temperature so it doesn't have to consume cooling energy. In this paper, the cooling energy savings was studied when a dehumidification system was applied in a model building instead of a chiller. The sensible heat load was almost the same result, but the latent heat load was decreased by 38.9% and the total heat load was decreased by 8.5%. As a result, electric energy used to drive the compressor in a chiller was saved by applying a membrane air-conditioning system instead.

Numerical Simulation for Urban Climate Assessment and Hazard (도시기후 평가와 방재를 위한 도시기상 수치모의)

  • O, Seong-Nam
    • Magazine of the Korean Society of Hazard Mitigation
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    • v.2 no.4 s.7
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    • pp.40-47
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    • 2002
  • Since it is important to understand the bio-climatic change in Seoul for ecological city planning in the future, this paper gives an overview on bio-climate analysis of urban environments at Seoul. We analyzed its characteristics in recent years using the observations of 24 of Automatic Weather Station (AWS) by Korea Meteorological Administration (KMA). In urbanization, Seoul metropolitan area is densely populated and is concentrated with high buildings. This urban activity changes land covering, which modifies the local circulation of radiation, heat and moisture, precipitation and creating a specific climate. Urban climate is evidently manifested in the phenomena of the increase of the air temperature, called urban heat Island and in addition urban sqall line of heavy rain. Since a city has its different land cover and street structure, these form their own climate character such as climate comfort zone. The thermal fold in urban area such as the heat island is produced by the change of land use and the air pollution that provide the bio-climate change of urban eco-system. The urban wind flow is the most important climate element on dispersion of air pollution, thermal effects and heavy shower. Numerical modeling indicates that the bio-climatic transition of wind wake in urban area and the dispersion of the air pollution by the simulations of the wind variation depend on the urban land cover change. The winds are separately simulated on small and micro-scale at Seoul with two kinds of kinetic model, Witrak and MUKLIMO.

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A Study on Air Flow Analysis for the Internal Space of the Dehumidifying Air-Conditioning System with A Membrane (분리막 제습공조시스템의 내부 유동 해석에 관한 연구)

  • Jung, Yong-Ho;Park, Seong-Ryong
    • Korean Journal of Air-Conditioning and Refrigeration Engineering
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    • v.27 no.12
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    • pp.620-625
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    • 2015
  • The summer climate is very hot and humid in Korea. Humidity is an important factor in determining thermal comfort. Recently, research on dehumidification device development has been attempted to save the energy required for operating the dehumidifier. Existing dehumidification systems have disadvantages such as wasting energy to drive the compressor. Meanwhile, dehumidification systems with membranes can dehumidify humid air without increasing the dry bulb temperature. Therefore. they don't have to consume cooling energy. In this paper, the installation conditions for a membrane system were analyzed to improve the shape and optimum performance of the system. The results showed that the distance between elements was the critical system design factor, and that a distance of 20 mm was the optimal condition for the pressure drop and flow characteristics of the internal air flow.