• Title/Summary/Keyword: Thermal Development

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Development of comfort algorism for Indoor temperature chagne in Heating System (변동환경 대응을 위한 난방System의 쾌적 알고리즘 개발)

  • Kim, Dong-Gyu;Jeong, Yong-Hyun;Kum, Jong-Soo
    • Journal of Fisheries and Marine Sciences Education
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    • v.18 no.3
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    • pp.229-235
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    • 2006
  • This study investigated physiology and psychological response of subjects, when heat pump was operated long time within comfort temperature range. Eight subjects were participated for the experiment. Their age was from 22 to 25 years old. The results of this experiment will propose basic data for improving comfort control algorithm in fluctuating environment by using heat pump. When indoor temperature was controlled by heat pump, the conclusion was as follows. 1) When votes of subjects was considered, the thermal comfort neutrality or lower range helped formation of comfort sensation for subjects. 2) When room temperature was lower, thermal comforts of shoulder, knee and foot with subjects thermal comfort showed high correlation. And when room temperature was higher, thermal comfort of face region with subjects thermal comfort showed high correlation. 3) The necessity of temperature change after 50 minutes from initially operating heat pump demands the additional analysis against the physiological signal.

Development of an assessment tool for outdoor thermal environment (옥외 온열환경 평가시뮬레이션 기법의 개발)

  • Jee, Yong-Seung;Hwang, Hyo-Keun;Lim, Jong-Yeon;Song, Doo-Sam
    • 한국태양에너지학회:학술대회논문집
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    • 2009.11a
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    • pp.38-43
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    • 2009
  • Since most of the existing CFD simulation about thermal environment was limited as indoor environment, it is not appropriate to adopt the same method for external thermal environment, because the solar radiation highly affect the outdoor thermal environment. Thus, in case of assessing the outdoor thermal environment, the radiation calculation is very important. In this study, as a new method to evaluate the outdoor thermal environment, coupled simulation of convection and radiation will be proposed.

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Electrical Degradation of Stator Bars for Large Turbine Generator after 1000 Thermal Cycles (대형 터빈 발전기용 고정자 권선의 1000 thermal cycle 후 전기적 특성 변화)

  • Kang, Myung-Guk;Kim, Tae-Hee;Lee, Jai-Kwun
    • Proceedings of the KIEE Conference
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    • 2007.07a
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    • pp.975-976
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    • 2007
  • Thermal and mechanical stresses, caused by repetitive start and stop and load fluctuation during long time operation, on winding stator bars are one of the main causes for electrical degradation of insulating materials. To understand the degradation process, we manufactured bar specimens with the same processes that make generator winding stator bars and the specimens were subjected to various degrees of thermal cycling. Measurements of the insulation properties, such as dissipation factor, tip-up and partial discharge, for un-aged specimens and for specimens aged by thermal cycling at 50, 100, 250, 500 and 1000 thermal cycles were performed. Finally all specimens were tested to obtain electrical breakdown voltages. In this paper we present the data and electrical degradation analysis results obtained during this program.

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A MATLAB-based Approach for Visualization of Human Thermal Psychology (MATLAB 기반 열심리 가시화 기법)

  • Gineesh Gopi;Mohammad F. B. Suhaimi;Seong Eun Yoon;Hyunjin Lee;Jung Kyung Kim
    • Journal of the Korean Society of Visualization
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    • v.21 no.2
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    • pp.72-82
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    • 2023
  • Effective thermal management in a battery electric vehicle (BEV) is crucial for reducing energy consumption and maximizing driving range in cold climates. Consequently, original equipment manufacturers are actively investing in the development of local heating systems. Visualizing occupant thermal behaviors or comfort can readily provide valuable insights that would substantially impact the design and control strategies of such microclimate systems. This study uses MATLAB for three-dimensional visualization of human thermal psychology. The developed program enables qualitative assessment of occupant comfort in BEVs.

Development of Thermal Distortion Analysis Method on Large Shell Structure Using Inherent Strain as Boundary Condition (고유변형도를 경계조건으로 갖는 대형 각(殼) 구조물 열변형 해석법 개발)

  • Ha, Yun-Sok
    • Journal of the Society of Naval Architects of Korea
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    • v.45 no.1
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    • pp.93-100
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    • 2008
  • There are two ways of conventional thermal distortion analysis. One is the thermal elasto-plastic analysis and the other is the equivalent forces method based on inherent strain. The former needs exorbitant analysis time, while the latter cannot obtain results of stress field and it needs much time consumption with loads modeling on curved plates. Such faults in two methods have made difficulties in thermal distortion analysis of a large structure like ship hull. In order to solve them, new kind of thermal distortion analysis method was developed. We devised that the inherent strains was used as direct input factors in forms of boundary conditions. It was embodied by using thermal expansion coefficient in commercial code. We used the pre-calculated inherent strain as thermal expansion coefficient, and endowed nodes with imaginary temperatures. This method was already adopted at hull block welding distortion analysis which was considered as impossible, and gave productive results such as reduction of work time in the dry dock.

Technology of Air-Conditioning System by Ocean Thermal Energy near Busan Coast (부산지역 해수온도차이용 냉난방기술)

  • Oh, Cheol;Kim, Meong-Whan;Lim, Tae-Woo;Choi, Young-Do
    • Proceedings of the SAREK Conference
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    • 2009.06a
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    • pp.350-355
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    • 2009
  • Air-conditioning system by ocean thermal energy has been developed in the areas of Europe, North America and Japan because there are abundant amount of thermal energy potential in the ocean and permanent free use for the thermal energy using the air-conditioning system. In the case of domestic ocean thermal energy resource, ocean thermal energy potential exists about 27,155Tcal/year and totally 20,285Tcal/year of possible thermal energy use by heat pump, which are reported from the survey of the 7 domestic near shore cities. Present study is aimed to survey the current development status of domestic and overseas air-conditioning system by ocean thermal energy, especially, for the air-conditioning facility technologies using sea water.

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Development of Photothermal Mirage Technique for Measuring Thermal Diffusivity (열확산도 측정을 위한 광열 신기루 기법 개발)

  • Choi, Sun-Rock;Lee, Joo-Chul;Kim, Dong-Sik
    • Transactions of the Korean Society of Mechanical Engineers B
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    • v.27 no.9
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    • pp.1220-1228
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    • 2003
  • The mirage technique is proved to be powerful in measuring the thermal diffusivity of materials. In particular, its contactless nature makes it suitable for delicate samples and microscale structures. In this study, thermal-wave-coupling method is developed in a general form for both thermally thin and thick samples. In the suggested measuring scheme, the probe beam can be positioned close to the pump beam and the absolute position need not be measured. Therefore the new scheme provides a relatively simple yet effective way to determine the thermal diffusivity of thermally thick samples. Thermal diffusivities of bulk samples like Ni and Al were measured and the characteristics of mirage signal for a thin film were observed by using the mirage experimental setup. The apparent thermal diffusivity was measured by varying such parameters as probe beam height, size of pump beam, power of pump beam, and surface condition of sample. From the practical standpoint, it is shown that the size of the pump beam is the most important factor for accurate thermaldiffusivity measurement. Experiments using thin-film samples show that the thermal diffusivity of a substrate covered with thin film can be measured by photothermal mirage signals.