• Title/Summary/Keyword: Thermal-Comfort

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Effect of Supply and Return Locations of a Floor-Supply Cooling System on Thermal Comfort

  • Kim, Young-Il;Kim, Jo-Seph;Yoo, Ho-Seon
    • International Journal of Air-Conditioning and Refrigeration
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    • v.9 no.4
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    • pp.37-46
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    • 2001
  • This study numerically investigates thermal comfort of a space cooled by a floor-supply air-conditioning system, in which three different combinations of supply and return locations, one floor-supply/ceiling-return and two floor-supply/floor-return, are treated. A complementary experiment is performed to validate the present numerical analysis, and the prediction agrees favorably with the measured data. In the numerical procedure, a simplified model mimicking the inlet flow through a diffuser is developed for efficient simulations. The calculated results show that the ceiling-return type is far better in terms of thermal comfort than the floor-return ones within the extent of this study, which seems to be caused by effective vertical penetration of the supply air against natural convection. It is also revealed that the arrangement of port locations in the floor-supply/floor-return system has insignificant effect on the cooling performance. For selecting a proper system, other characteristics including the heating performance should be accounted for simultaneously with the present considerations.

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A Study on Acceptable Thermal Comfort Zone and Resident Behavior of Operating Cooling Devices in Apartments (공동주택의 여름철 수용 쾌적온도 범위와 거주자의 냉방기 사용행위에 관한 연구)

  • Chun Chung-Yoon;Bae Nu-Ri
    • Korean Journal of Air-Conditioning and Refrigeration Engineering
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    • v.17 no.5
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    • pp.477-486
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    • 2005
  • In this study, indoor thermal environment, resident behavior of operating cooling device, and thermal comfort vote are investigated at the living room of apartment during summertime in Seoul. Based on the results of the investigation, indoor air temperatures that residents turn air conditioners (especially for cooling load in this research) on and off were found out. The relationships between outdoor weather condition and the number of days using air conditioner, and whether operating patterns of the devices were also found out. The acceptable thermal comfort zone is figured out from these results, and this research is expected to contribute to the development of household air conditioner. The results can be summarized as the followings; Residents turned the air conditioner on at $29.76^{\circ}C$ of indoor air temperature, and $28.89^{\circ}C$ of $SET^\ast$. And turned the air conditioner off at $27.31^{\circ}C$ of indoor air temperature, and $23.70^{\circ}C$ $SET^\ast$. Therefore, acceptable thermal comfort zone could be lied between these temperatures. If comfortable indoor thermal environment can be obtained with various architectural passive cooling techniques based on the results, energy consumption of cooling devices will be reduced.

A study on characteristics of thermal comfort for artificial environmental experiment in winter (동계 인공환경실험에 의한 온열쾌적특성 연구)

  • 박종일;김경훈;정성일
    • Korean Journal of Air-Conditioning and Refrigeration Engineering
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    • v.10 no.6
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    • pp.721-731
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    • 1998
  • Recently, many researchers are studying the relation between thermal environment and human comfort. The purpose of this study was to obtain basic data which are necessary to determine the thermal comfort sensation and physiological responses for men in winter indoor environment. From January to February 1998, subject experiment was 40 times proceeded under twenty different conditions of air temperature and relative humidity with early-twenty male university students. We examined subjective evaluation, Electrocardiogram(ECG), Electroencephalogram(EEG) of subjects. The results of this study can be summarized as follows : The comfort zone of people in winter was achieved at Standard new effective temperature($SET^*$) $ 25.2^{\circ}C$, PMV range was obtained by Fanger's statistical calculation was -0.27<PMV<+0.62, TSV range obtained subjects vote was -0.76<TSV<+0.36. The largest difference of skin temperature was found at the calf area as air temperature changes. vote rate of human body presented calflongrightarrowheadlongrightarrowforearmlongrightarrowchestlongrightarrowabdo men in turn. Heart rate was decreased at low $SET^*$ and heart rate was increased at high $SET^*$ But there was no change at EEG.

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Analysis of Thermal Sensation and Wearing Comfort before and after Bikram Yoga Activity

  • Lee, Hyojeong;Jin, Heejae;Lee, Yejin
    • Journal of the Korean Society of Clothing and Textiles
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    • v.44 no.5
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    • pp.810-823
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    • 2020
  • This study evaluated the effect of functional characteristics of the fabric for Bikram yoga clothing and fit measured in clothing pressure on the wearer's physiological response and perceptive sensation before and after exercise in hot conditions and during a resting period in standard conditions. The test garment consisted of two tops (T1, T2) and two pants (P1, P2) each with different functional characteristics of fabric. Using various combinations of the test garments, assessment of the thermal sensation and comfort was performed before/after yoga and after resting. This study revealed that thermal sensation and wearing comfort significantly changed based on the functionality of the fabric of top garment before the exercise period. In addition, the results showed that based on clothing pressure, the feeling of comfort was different between before yoga and after resting. The appropriate choice of fabric material was important when constructing Bikram yoga clothing worn in hot conditions; however, level of clothing pressure was also found to be an essential design factor for comfort during rest after exercise.

A Product-Focused Process Design System(PFPDS) for High Comforts Artificial Leather Fabrics (고감성 인조피혁개발을 위한 제품중심 공정설계 시스템)

  • Kim, Joo-Yong;Park, Baek-Soung;Lee, Chae-Jung
    • Textile Coloration and Finishing
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    • v.20 no.6
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    • pp.69-74
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    • 2008
  • In this paper, a comfort evaluation system based on a product-focused process design (PFPD) has been proposed for high comforts interior seat covers. Correlations between comforts properties and physical/thermal properties of interior seat covers were examined by combining traditional regression analysis and data mining techniques. A skin sensorial comfort of leather samples was evaluated by only human tactile sensation. The adjectives of leather car seat covers are 'Soft', 'Sticky' and 'Elastic'. Thermo-physiological comfort properties of leather samples were evaluated by only human tactile sensation. The adjectives of leather car seat covers are 'Coolness to the touch' and 'Thermal and humid'. Skin sensorial comforts of cloth samples were evaluated by only human tactile sensation. The adjectives of cloth car seat covers are 'Soft', 'Smooth', 'Voluminous' and 'Elastic'. Thermo-physiological comforts of cloth samples were evaluated by only human tactile sensation. The adjectives of cloth car seat covers are 'Coolness to the touch' and 'Thermal and humid'.

A Study on Relationship of Fabric Physical Properties and Subjective Properties for Clothing Comfort (피복재료의 물리적특성과 주관적착용감과의 관계연구)

  • Choi Chul Ho;Park Woo Mee
    • Journal of the Korean Society of Clothing and Textiles
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    • v.10 no.2
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    • pp.29-35
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    • 1986
  • The main purpose of the study was to investigate relationships between subjective evaluation of comfort/discomfort and tactile sensation. It was also attempted to analyse physical properties of fabric, hence to find physical factors which have effects on wearing- comfort. The results were as follows; 1. Polyester fabric B Type ranked the highest on subjective comfort scale of T-shirts. 2. Scratchiness and flexural rigidity among subjective factors were important on overall comfort sensations of the subjects. 3, In winter, subjective factors, suchas Soratchiness, Heaviness & Flexural Rigidity, were significantly correlated with objective factors of Scratchiness, Thickness & Weight, Stiffness, respectively. 4. In summer, subjective factors such as warmth, Heaviness, Clammy & Cling Tension, Flexural Rigidity, were significantly correlated with objective factors of Thermal Insulation, Thickness & Weight, Cling Tension and stiffness, respertively. 5. Scratchiness, Weight, Stiffness & Thermal Insulation among objective factors were important on overall comfort sensation of the subjects.

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Effect of the Vertical Air Circulation on the Thermal "Environment in a Large Space (대공간 열환경 특성에 관한 수직순환기류의 영향)

  • 김경환;강석윤;최충현;조영진;이재헌;오명도
    • Korean Journal of Air-Conditioning and Refrigeration Engineering
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    • v.12 no.6
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    • pp.581-588
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    • 2000
  • This paper describes the effect of vertical air circulation on the thermal environment in an airport passenger terminal with induced flow by jet fans. In comparing the level of thermal comfort at the breathing line of 1.5 m in height, the results from the two models with or without the vertical air circulation, show that the average PPD is 8% in the former and 23% in the latter, respectively. It is thought that vertical air circulation lends to improved thermal comfort for human in respect of ventilation in a large space.

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Analysis of Indoor Thermal Environment and Energy Consumption in Office Building Controlled by PMV (PMV 제어에 따른 사무소 건물의 실내열환경과 에너지소비량 분석)

  • Jang, Hyang-In;Suh, Seung-Jik
    • Journal of the Korean Solar Energy Society
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    • v.33 no.4
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    • pp.15-22
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    • 2013
  • The purpose of this study is to analyse the effects of air conditioned room controlled by PMV(Predicted Mean Vote)for energy consumption and human comfort in office building. The 'EnergyPlus' was used for the evaluation of indoor thermal environment and energy consumption by the controls of room temperature and PMV. The result indicates that the PMV control could prove more profitable method for improvement of indoor thermal environment and energy conservation. Consequently, PMV control has a distinct advantage over most other control methods. An additional study is required to establish the various thermal comfort control for rooms on the basis of this work.

Characteristics of Thermal Environment and Evaluation of Thermal Comfort in Task Area with Personal Air-Conditioning System(PACS) (개별공조시스템(PACA)을 적용한 작업공간에서의 온열환경 특성 및 쾌적성 평가)

  • 최익순;정광섭;박영철;한화택;이정재
    • Korean Journal of Air-Conditioning and Refrigeration Engineering
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    • v.13 no.2
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    • pp.106-114
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    • 2001
  • The office environment of the building has been significantly changed and the office automation(OA) for productivity improvement and efficiency has proceeded. According to thee trends, the concept of office environment was transferred from conventional \"working space\" to \"living space\" or \"creative space\". Thus, occupants in office building have demanded more comfortable and advanced task environment. The objective of this paper is to evaluate the indoor environment of working space with personal air conditioning system using the measurements of environmental comfort parameters and the questionnaire survey of occupants、 thermal sensation response to the environment.n response to the environment.

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Investigation of school building microclimate using advanced energy equipment: Case study

  • Alwetaishi, Mamdooh;Alzaed, Ali;Sonetti, Giulia;Shrahily, Raid;Jalil, Latif
    • Environmental Engineering Research
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    • v.23 no.1
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    • pp.10-20
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    • 2018
  • Buildings are responsible of major energy consumption globally. In addition, they are linked to thermal comfort. The need to provide comfort becomes more crucial in schools as they are the place where students learn, and develop their skills. This research aims to investigate the energy responsiveness of new and traditional school building design, where major variation in form, amount of external walls and glazing are different. The research focused on indoor microclimate condition of selected schools in the city of Jeddah where the climate is hot and humid using advanced tools for monitoring. The research uses advanced energy equipment to measure several aspects such as floor temperature, roof temperature, globe temperature and other factors which can lead to predictable thermal comfort of users. The findings suggest that a larger area of glazing shielded from sunlight has a greater influence on both indoor condition and general thermal sensation. The finding also suggests that the glazing ratio is a major contributor on indoor thermal pattern which can result in an increase in temperature profile between from $7-10^{\circ}C$. The findings of this research can assist in the improvement in the design of the prototype school building in hot and humid climate.