• Title/Summary/Keyword: Outdoor Thermal Condition

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Signal Analysis of Inverter-Type Outdoor Unit for Detecting Operation Changes of Commercial Refrigerator (상업용 냉장고의 상황 감지를 위한 인버터형 실외기 신호 분석)

  • Lim, Hyo Joon;Lee, Ju Kyoung;Hwang, Jun Hyeon;Lee, Kyung Chang;Lee, Suk
    • Journal of the Korean Society for Precision Engineering
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    • v.33 no.6
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    • pp.517-523
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    • 2016
  • Unlike household refrigerators, commercial refrigerators are composed of separate indoor and outdoor units. The outdoor unit of most commercial refrigerators is designed to run at a fixed speed, which results in low energy efficiency and loud fan noise. Moreover, it cannot respond flexibly to changing thermal load in the indoor unit. Inverter type outdoor units can address such problems through speed changes based on information obtained from the indoor unit. However, using two units from different manufacturers is often not a viable solution. If condition changes in the indoor unit can be detected without communication between the two units, it is possible to adjust the speed of the outdoor unit. This paper attempts to analyze the signal from the outdoor unit when the condition of the indoor unit changes by varying the thermal load.

Thermal Comfort Condition of Temperature and Humidity in Loess Interior Space

  • Kong, Sung-Hoon
    • Biomedical Science Letters
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    • v.10 no.2
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    • pp.129-135
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    • 2004
  • The study was carried out through measuring the temperature and humidity of the indoor/outdoor space and the distribution of interior thermal condition, and investigating the effect of loess materials on human body. The purpose of this study is to analyze the change of dry bulb temperature and relative humidity and correlation of thermal reaction of human body with ASHRAE (American Society of Heating, Refrigerating and Air-conditioning) comfort chart in the loess interior space. In the view point of biomedical sciences, loess interior space provides optimum thermal conditions for human thermal sensation.

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Thermal Characteristics Analysis by Ambient and Operating Temperature according to the Kinds of Terminations in Underground Power Cable Systems (지중송전케이블 종단접속함 종류에 따른 외기 및 운전온도에 의한 열특성 분석)

  • Jung, Chae-Kyun;Kang, Ji-Won;Lee, Bang-Wook
    • The Transactions of The Korean Institute of Electrical Engineers
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    • v.64 no.8
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    • pp.1154-1160
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    • 2015
  • This paper describes the thermal characteristics of underground power cable system terminations according to the change of ambient temperature as well as operating temperature. Recently, the failure has been gradually increasing in outdoor termination during winter season because the power demand was increased by electricity heating system. The power demand and outdoor temperature is difference between day time and night time. The temperature difference has an influence on conductor extension and shrinkage due to conductor force as well as thermal mechanical characteristics. These phenomena have daily repeated during heating and cooling period of conductors. In these cases, the insulation of outdoor terminations might be degraded by the reduced interface pressure surrounding stress relief cone. Therefore, in this paper, the thermal characteristics are variously analysed by simulation considering power demand and ambient temperature condition during winter season at epoxy type termination as well as slip-on type termination

A Study on Thermal Comfortable Following the Thermal Environment Migration in Detached Housing Area (열환경 완화를 통한 주택지내 쾌적성 확보에 관한 연구)

  • Ryu, Ji-Won;Jung, Eung-Ho;Hoyano, Akira;Kim, Dae-Wuk
    • Journal of the Korean housing association
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    • v.24 no.1
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    • pp.51-59
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    • 2013
  • This study aims to improve the thermal comfort level of detached housing area by reducing the impact of thermal environment. The study focused on reducing surface temperature that is generated in buildings and adjacent spaces as a result of sensible heat load and presented a proposal on implementing planting method considering its outdoor condition and structure and composed materials. To perform the study, we utilized 3D-CAD to examine the outdoor condition and structure and composed materials that impact on surface temperature and conducted space design after reflecting climatic elements in simulations. The result is as follows. In reviewing temperature distribution of Heat Island Potential (HIP) of buildings and adjacent spaces, in case where green coverage ratio is increased, there was a $6^{\circ}C$ temperature difference and in regard to changes in the thermal environment in detached housing area, in case where rooftop planting, surface improvement, planting, and overall green coverage ratio is increased, there was a $10^{\circ}C$ temperature difference. In addition, there was difference in temperature in detached housing area following the changes in wind.

Predictive Evaluation of Outdoor Thermal Environment of Flat-type Apartment Houses and Tower-type Apartment Houses in summer (판상형 및 탑상형 아파트의 여름철 옥외 열환경 예측 평가)

  • Jeong, Seon-Yeong;Yoon, Seong-Hwan
    • Proceedings of the SAREK Conference
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    • 2008.06a
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    • pp.877-882
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    • 2008
  • The purpose of this study is to analyze the characteristics of outdoor thermal environment of flat-type apartment houses and tower-type apartment houses in summer by numerical simulation. After inputting a building condition at CAD, we calculated the surface temperature for two apartments by using the numerical simulation of a clear sky day in summer in Seoul. The results indicated that the variation in Heat Island Potential(HIP) of tow apartments were not only in the day but also in the night. According to form of apartment the flat-type apartment houses appeared $1.3^{\circ}C$ more highly tower-type apartment houses.

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Analysis on Living Factor and Present Condition of Indoor Thermal Environment in Apartment Units during Winter (아파트의 겨울철 실내온열환경 실태와 생활요인 분석)

  • Choi, Yoon-Jung;Jeong, Youn-Hong
    • Proceeding of Spring/Autumn Annual Conference of KHA
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    • 2008.04a
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    • pp.281-284
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    • 2008
  • The purposes of this study were to make clear the present condition of indoor thermal environment in apartment units and to analyze the relation of the living factors with indoor thermal elements. The field surveys consisted of measurements on physical elements and observations on living factors and interview on resident's subjective responses were carried out in 20 apartment units. The field surveys were carried out during the $January{\sim}March$ 2007. Measuring elements were air temperature, globe temperature, and relative humidity. As results, the averages of indoor temperature each houses were $21.2{\sim}27.2^{\circ}C$, the number of houses exceed the comfort zone were 4. The averages of globe temperature each houses were $21.3{\sim}27.5^{\circ}C$, 6 houses exceeded the comfort zone. The means of relative humidity were $19.5{\sim}58.8%$, relatively dry condition. The clothing value of residents were $0.39{\sim}0.89$ clo(average 0.68 clo). The average of thermal sensation ratings each room were $4.2{\sim}4.8$, 'neutral'$\sim$'slightly warm'. The results of regression analysis on relations of living factors with the thermal elements are as follow; ventilation time(outdoor air exchange), door opening time with balcony, and gas cooker use time had significant effect on indoor temperature.

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Dynamic Simulation of a Dedicated Outdoor Air-conditioning System (외기 전용 공조기의 동특성 시뮬레이션)

  • Kim, Jung-Min;Kim, Young-Il;Chung, Kwang-Seop;Park, Seung-Tae
    • Proceedings of the SAREK Conference
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    • 2007.11a
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    • pp.322-327
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    • 2007
  • Dedicated outdoor air-conditioning(DOA) system that utilizes pre-cooling and desiccant dehumidification can be superior to conventional cooling and reheating system with respect to energy consumption and indoor thermal comfort. In this work, simulation has been conducted to study various factors that affect the performance of DOA. Dynamic simulation shows the transient variation of temperature and humidity as the on/off control logic is imposed. Exit humidity of process air and flow rate are varied to study the effect on exit temperature of process air, dehumidification quantity, required regeneration temperature and exit humidity of regeneration air. For an outdoor air condition of $28.5^{\circ}C$ temperature, 16 g/kg humidity ratio and 2000 cmh flow rate, the dehumidification efficiency is increased by 4.6% as the flow rate is doubled.

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Effect of Tension and Wind Velocity on Temperature of ACSR Overhead Conductor (장력과 풍속이 ACSR 가공송전선의 온도에 미치는 영향)

  • Kim Shang-Shu;Kim Byung-Geol;Lee Dong-Il;Min Byung-Uk
    • Journal of the Korean Institute of Electrical and Electronic Material Engineers
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    • v.19 no.5
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    • pp.480-485
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    • 2006
  • A research was undertaken on the thermal properties and behavior of the conductors in a controlled chamber, which was designed to implement the outdoor air temperature, heat and wind conditions With ACSR $410mm^2$ overhead conductors, we measured the maximum temperature of the conductors and the temperature gradient from the core to the surface regions as a function of current, tension, wind velocity and outdoor air temperature. This test also provided a comparative analysis between the measured temperature values of conductors in the controlled chamber and the theoretical calculations of ANSI/IEEE at normal condition. There was not much influence of tension on the conductor temperature. However, the compactness of conductor wires increased with an increase in tension, which eventually increased the coefficient of effective thermal conductivity and, accordingly the conductor temperature was reduced more or less.

Comparisons of Thermal Insulations between on Air-Cell Pack Embedded Jacket and Down Jackets (공기주입형 의복의 보온력 측정 및 다운재킷의 보온력과의 비교)

  • Kim, Yung-Bin;Jang, Won;Kim, Kirim;Kim, Siyeon;Baek, Yoon Jeong;Lee, Joo-Young
    • Journal of the Korean Society of Clothing and Textiles
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    • v.39 no.1
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    • pp.55-62
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    • 2015
  • This study investigated the thermal insulation of an air-cell pack embedded jacket and down jackets to understand the potential of air-cell pack as a filler for winter outdoor wear. A thermal manikin measured the thermal insulation of the following jackets: HD (heavy down jacket, total weight (Tw) 750g, goose down weight (Dw) 350g), LD (light down jacket, Tw 560g, Dw 140g), AF (air-cell pack embedded jacket, Tw 490g, trunk goose down in LD was replaced to air cell), F (film jacket, Tw 469g, but removed the air in the air-cell pack from the AF), and Control (control jacket, Tw 438g, removed the air-cell pack film from the F). Thermal insulations of each experimental condition were measured in a static standing posture. Total thermal insulations (IT) were 1.29clo (HD), 1.23clo (LD), 1.16clo (AF), 1.20clo (F), and 1.08clo (Control). Body regional thermal insulation was higher in the chest and back than in the abdomen and hip in all conditions. The results suggest that an economical and versatile outdoor jacket with superior thermal insulation will be feasible if the air volume is properly controlled in air-cell pack embedded jackets in consideration of regional different distribution and used in combination with film and down.

A Study on Examination of Indoor Thermal Environment Elements and Thermal Sensation Vote of Log Cabins in Winter Season (통나무집의 동절기 실내 온열환경 요소의 측정과 온열감 평가에 관한 연구)

  • Min, Byeong-Cheol;Jeon, Ji-Hyeon;Kook, Chan
    • Journal of the Korean housing association
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    • v.18 no.2
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    • pp.21-27
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    • 2007
  • Various buildings constructed by environmentally friendly resources are being built in KOREA. Especially as the wood has distinctive ecological merits in comparison with reinforced concrete and brick, the buildings made by the wood are acknowledged with its superiority of ecological value. Enough field studies for their thermal environment, however, haven't been done. In this study, to investigate indoor environmental condition and occupants' response to it of Log Cabin in Gyeongsangnam-do Hamyang Country Jirisan Natural Recreation Forest, examination of indoor thermal environment and field subjective evaluation have been done in that fundamental information of thermal environment characteristics can be suggested. The results are following; 1) Thermal environment of the Log Cabins; Indoor and outdoor mean dry bulb temperature were $21.9^{\circ}C$ and $-3.1^{\circ}C$, and Indoor and outdoor average relative humidity were 25.8% and 52.1%. These results are below ASHRAE; dry bulb temp. $22.0^{\circ}C$, humidity 30%, and above domestic standards; dry bulb temp. $18{\sim}20.0^{\circ}C$, humidity $40{\sim}60%$. 2) Result of subjective evaluation; Thermal sensation and its comfort were evaluated as 'slightly uncomfortable' because of 'slightly warm'. And humid sensation and its comfort were evaluated as 'slightly uncomfortable' because of 'slightly warm'. 3) Result of vertical temperature and humidity; Vertical temperature difference from head to ankle was $0.54^{\circ}C$ which means most occupants may feel comfortable.