• 제목/요약/키워드: heat map

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해수열원 스크류 히트펌프의 연간 난방운전 성능 모사 (A Simulation Study on the Annual Heating Performance of the Seawater-Source Screw Heat Pump)

  • 백영진;김민성;장기창;이영수;김현주
    • 한국태양에너지학회 논문집
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    • 제32권3호
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    • pp.88-95
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    • 2012
  • In this study, in order to utilize the seawater as a heat source at Gangneung city near the East Sea in Korea, an annual heating performance of a screw heat pump was simulated. For a simulation, the maximum heating capacity of heat pump was assumed at 3.5 MW. An ambient temperature at Gangneung city was calculated from the TMY2 weather data, while the seawater temperature was calculated from the regression equation based on the measurement by the National Fisheries Research and Development Institute of Korea. The heating load was assumed linearly dependent on the ambient temperature, while the maximum heating load was assumed to appear when the ambient temperature is below $-2.4^{\circ}C$, which is the temperature of TAC 2.5% for heating at Gangneung city. A heat pump performance at full-load was calculated from the regression equation, which involves refrigerant's evaporating and condensing temperatures, based on a commercial screw compressor performance map. A heating supply temperature which determines refrigerant's condensing temperature was assumed linearly dependent on the heating load. A performance degradation due to the part-load operation of heat pump was also considered. Simulation results show that an annual heating coefficient of performance ($COP_H$) of a seawater-source screw heat pump is approximately 2.8 and that it is necessary to improve part-load performance to increase an annual performance of the heat pump.

해수열원 스크류 히트펌프의 연간 난방운전 성능 시뮬레이션 (A Simulation Study on the Annual Heating Performance of the Seawater-Source Screw Heat Pump)

  • 백영진;김민성;장기창;강병찬;라호상;김현주
    • 한국태양에너지학회:학술대회논문집
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    • 한국태양에너지학회 2012년도 춘계학술발표대회 논문집
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    • pp.488-493
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    • 2012
  • In this study, in order to utilize the seawater as a heat source at Gangneung city near the East Sea in Korea, an annual heating performance of a screw heat pump was simulated. For a simulation, the maximum heating capacity of heat pump was assumed at 3.5 MW. An ambient temperature at Gangneung city was calculated from the TMY2 weather data, while the seawater temperature was calculated from the regression equation based on the measurement by the National Fisheries Research and Development Institute of Korea. The heating load was assumed linearly dependent on the ambient temperature, while the maximum heating load was assumed to appear when the ambient temperature is below $-2.4^{\circ}C$, which is the temperature of TAC 2.5% for heating at Gangneung city. A heat pump performance at full-load was calculated from the regression equation, which involves refrigerant's evaporating and condensing temperatures, based on a commercial screw compressor performance map. A heating supply temperature which determines refrigerant's condensing temperature was assumed linearly dependent on the heating load. A performance degradation due to the part-load operation of heat pump was also considered. Simulation results show that an annual heating coefficient of performance ($COP_H$) of a seawater-source screw heat pump is approximately 2.8 and that it is necessary to improve part-load performance to increase an annual performance of the heat pump.

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건물과 수목의 그림자에 의한 도시의 열 분포 산정 및 저감효과 연구 (Estimating the urban radiation heat flux distribution and the reduction effect of building and tree shade)

  • 박채연;이동근;윤준하
    • 한국환경복원기술학회지
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    • 제21권6호
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    • pp.1-13
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    • 2018
  • Mapping radiation heat flux of urban area is essential for urban design and landscape planning. Because controlling urban geometry and generating green space are important urban design strategies for reducing urban heat, urban planner and designer need to recognize the micro urban heat distribution for adequate urban planning. This study suggests a new methodology for mapping urban radiation heat flux in a micro scale considering buildings and trees' shade. For doing that, firstly, we calculate net radiation for each urban surfaces (building, road (not shaded, building shaded, tree shaded), ground (not shaded, building shaded, tree shaded), tree (not shaded, building shaded)). Then, by multiplying the area ratio of surfaces to the net radiation, we can obtain the radiation heat flux in micro-scale. The estimated net radiation results were found to be robust with a $R^2$ of 90%, which indicates a strong explanatory power of the model. The radiation heat flux map for 12h $17^{th}$ August explains that areas under the building and tree have lower net radiation heat flux, indicating that shading is a good strategy for reducing incident radiation. This method can be used for developing thermal friendly urban plan.

여름철 택지개발지역의 열쾌적성에 관한 연구 (A Study on Human Thermal Comfort of Residential Development Districts in Summer Season)

  • 공학양;최낙훈;박성애;이종천;박수국
    • Ecology and Resilient Infrastructure
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    • 제5권4호
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    • pp.219-228
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    • 2018
  • 본 연구는 수원시 호매실 택지개발지구를 대상으로 토지피복지도와 도시기후 유형 분류 방법인 Local Climate Zone (LCZ)을 활용하여 기후적 특성에 따라 도시지역을 세분화하고, 각각의 지역에 대한 여름철 폭염 시 열환경 특성을 확인하고자 하루 중 가장 더운 낮 시간의 열쾌적성을 측정했다. 측정 결과 산림과 논은 중간 열스트레스 값을, 도시공원은 강한 열스트레스 값을 나타냈으며, 기타 시가화 지역은 극한 열스트레스 값을 나타냈다. 이러한 결과는 도시지역의 유형별 기후적 특성과 차이를 확인하고, 도시계획 수립 시 계획단계에서부터 폭염을 대비한 토지이용의 구상 및 그린인프라의 효율적인 배치를 통해 열환경 개선을 위한 정책적 활용 가능성이 있음을 보여주었다.

스마트 SNS 맵: 위치 정보를 기반으로 한 스마트 소셜 네트워크 서비스 데이터 맵핑 및 시각화 시스템 (Smart SNS Map: Location-based Social Network Service Data Mapping and Visualization System)

  • 윤장호;이승훈;김현철
    • 한국멀티미디어학회논문지
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    • 제19권2호
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    • pp.428-435
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    • 2016
  • Hundreds of millions of new posts and information are being uploaded and propagated everyday on Online Social Networks(OSN) like Twitter, Facebook, or Instagram. This paper proposes and implements a GPS-location based SNS data mapping, analysis, and visualization system, called Smart SNS Map, which collects SNS data from Twitter and Instagram using hundreds of PlanetLab nodes distributed across the globe. Like no other previous systems, our system uniquely supports a variety of functions, including GPS-location based mapping of collected tweets and Instagram photos, keyword-based tweet or photo searching, real-time heat-map visualization of tweets and instagram photos, sentiment analysis, word cloud visualization, etc. Overall, a system like this, admittedly still in a prototype phase though, is expected to serve a role as a sort of social weather station sooner or later, which will help people understand what are happening around the SNS users, systems, society, and how they feel about them, as well as how they change over time and/or space.

HTML5 Canvas를 활용한 시각적 공간분석 환경의 설계와 구현 (Design and Implementation of a Computing Environment for Geovisual Analytics Using HTML5 Canvas)

  • 박미라;박기호;안재성
    • 한국지리정보학회지
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    • 제14권4호
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    • pp.44-53
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    • 2011
  • 이 연구에서는 HTML5 canvas를 활용하여 시각화 도구와 사용자와의 동적 상호작용을 지원하는 웹 기반의 시각적 공간 분석 환경을 설계하고 구현하였다. 분석 환경은 군집지도, 애니메이션 지도, 시간적 평행좌표 그림, 시계열 히트 맵 차트와 같은 시각화 도구로 구성되어 있다. 분석환경에서는 동일한 군집으로 분류된 지역의 속성 변화를 살펴볼 수 있는 다중창 배열과 선별적 강조를 기반으로 하는 패턴 탐색이 가능하다. 그리고 크로스 브라우저를 지원하기 때문에 다양한 정보 기기를 사용하는 컴퓨팅 환경에서도 활용할 수 있다.

Reproductive Responses of Awassi Ewes Treated with either Naturally Occurring Progesterone or Synthetic Progestagen

  • Husein, Mustafa Q.;Kridli, Rami T.
    • Asian-Australasian Journal of Animal Sciences
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    • 제15권9호
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    • pp.1257-1262
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    • 2002
  • The objective was to identify the appropriate form of progesterone, which exhibits compact reproductive responses in Awassi ewes during mid to late seasonal anestrous period. Forty-eight Awassi ewes were randomly allocated into four groups to be treated with 60 mg medroxyprogesterone acetate (MAP), 30 mg fluorogestone acetate (FGA), 40 mg FGA, or 600 mg progesterone sponges. After a 12 day period, sponges were removed and ewes were administered i.m. with 600 IU PMSG (d 0, 0 h). Five harnessed Awassi rams were turned-in with the ewes to detect heat. Ewes were checked for breeding marks at 6 h intervals for 5 days. Blood samples were collected from all ewes for analysis of progesterone concentrations. Pretreatment (d -13 and -12) progesterone concentrations were ${\leq}0.2ng/mL$ among all ewes and were indicative of seasonal anestrous period. On d 0, progesterone concentrations were elevated to $1.4{\pm}0.1ng/mL$ in ewes received progesterone sponges only and were higher (p<0.0001) than those (${\leq}0.2ng/mL$) administered MAP or FGA sponges. Progesterone concentrations returned to their basal values of <0.2 ng/mL within 24 h of sponge removal and were similar (p>0.1) among all ewes. Incidence of estrus was similar (p>0.1) among the four groups and occurred in 75% (9/12), 82% (9/11), 67% (8/12) and 58% (7/12) of the ewes receiving MAP, 30 mg FGA, 40 mg FGA and progesterone sponges, respectively. Estrous responses occurred 14.7, 20 and 13.6 h earlier in progesterone-sponge-treated ewes than those of MAP- (p<0.04), 30 mg FGA- (p<0.01) and 40 mg FGA-treated (p=0.06) ewes, respectively. Induced estrus conception rates were 50% (6/12), 55% (6/11), 50% (6/12) and 42% (5/12), out of which 4/6, 4/6, 3/6 and 3/5 lambed 151 days following d 0, and were similar (p>0.1) among ewes of the four treatment groups. Ewes that returned to estrus 16 to 20 days following d 0 were 5/12, 5/11, 6/12 and 4/12 ewes treated with MAP, 30 mg FGA, 40 mg FGA and progesterone sponges, respectively, and all lambed 169 days later. Overall lambing rates were 75% (9/12), 82% (9/11), 75% (9/12) and 58% (7/12) ewes treated with MAP, 30 mg FGA, 40 mg FGA and progesterone sponges, respectively. Results demonstrate that applications of MAP, 30 mg FGA, 40 mg FGA and progesterone sponges Awassi ewes were equally effective in induction of estrus and tended to favor both types of FGA and MAP in overall lambing rates over progesterone sponges during the seasonal anestrous period.

착상 및 제상을 포함한 VRF 히트펌프의 동적 수치해석 모델 (A New Dynamic VRF Heat Hump Simulation Including Frosting and Defrosting Models)

  • 박노마;신정섭;정백영;김병순
    • 대한기계학회논문집 C: 기술과 교육
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    • 제3권1호
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    • pp.1-13
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    • 2015
  • 실외 열교환기의 착상 및 제상조건 하에서 VRF 멀티형 히트펌프의 동적 거동의 해석을 위한 시뮬레이션 기법이 제안되었다. 이를 위해 열전달-물질전달 완벽 상사 가정에 기반한 간단한 착상모델과 제상 모델이 제안되었다. 제안된 착제상 모델은 용량가변 압축기 모델과, 미소면적에 대한 열 및 모멘텀 평형에 근거한 열교환기 모델을 채택한 동적 사이클 해석모델에 적용되었다. 따라서, 제안된 모델은 공간에 대해 비균질 착상을 자연스럽게 예측할 수 있다. 개발된 동적 사이클 해석 모델은 실험결과와 비교하여 능력 및 효율을 10% 이내에서 잘 예측함을 확인하였다. 최종적으로, 개발된 모델은 표준적인 건물의 난방시즌 운전 해석에 적용되었으며, 착상 및 제상으로 인하여 동절기의 계절 성능계수를 7% 가량 하락 시킴을 보일 수 있었다.

니오븀이 첨가된 Zr 합금 스트립의 부식 및 기계적 특성에 대한 중간열처리 영향 (Effects of Intermediate Heat Treatment on the Corrosion and Mechanical Properties of Zr Alloy Strip Incorporating Nb)

  • 이명호;정양일;최병권;박상윤;김현길;박정용;정용환
    • 대한금속재료학회지
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    • 제47권8호
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    • pp.482-487
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    • 2009
  • In order to investigate the effects of intermediate heat treatment between cold rolling passes on the hardness and corrosion properties of a Zr alloy incorporating Nb (Zr-1.49Nb-0.38Sn-0.20Fe-0.11Cr) strip, three different intermediate heat treatment processes ($580^{\circ}C{\times}4hrs$, $600^{\circ}C{\times}2hrs$ and $620^{\circ}{\times}1hrs$) were designed based on a recrystallization map and an accumulated annealing parameter. Test samples from the different processes were investigated by a hardness test, corrosion test, and microstructure analysis and appropriate heat-treatment conditions were thereupon proposed. The sample subjected to an intermediate heat treatment of $580^{\circ}C{\times}4hrs$ was harder than that undergoing $600^{\circ}C{\times}2hrs$ and $620^{\circ}C{\times}1hr$ while the corrosion resistance of the sample that received an intermediate heat treatment of $580^{\circ}C{\times}4hrs$ was superior to that of the other specimens. Considering the trade-off of hardness and corrosion resistance, an intermediate heat treatment process of $600^{\circ}C{\times}2hrs$ is proposed to improve the manufacturing process of the alloy strip.

Microstructural and corrosion behavior of D3 tools steel and 440C SS for blade application

  • Nur Maizatul Shima Adzali;Nurul Abidah Mohamad Khapeli;Alina Rahayu Mohamed
    • Advances in materials Research
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    • 제13권3호
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    • pp.183-194
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    • 2024
  • D3 tools steel and 440C stainless steel (SS) are normally being employed for application such as knife blade and cutting tools. These steels are iron alloys which have high carbon and high chromium content. In this study, lab work focused on the microstructural and corrosion behavior of D3 tools steel and 440C SS after went through heat treatment processes. Heat treatments for both steels were started with normalizing at 1020 ℃, continue with hardening at 1000 ℃followed by oil quenching. Cryogenic treatment was carried out in liquid nitrogen for 24 hours. The addition of cryogenic heat treatment is believed to increase the hardness and corrosion resistance for steels. Both samples were then tempered at two different tempering temperatures, 160 ℃ and 426 ℃. For corrosion test, the samples were immersed in NaCl solution for 30 days to study the corrosion behavior of D3 tool steel and 440C SS after heat treatment. The mechanical properties of these steels have been investigated using Rockwell hardness machine before heat treatment, after heat treatment (before corrosion) and after corrosion test. Microstructure observation of samples was carried out by scanning electron microscopy. The corrosion rate of these steels was calculated after the corrosion test completed. From the results, the highest hardness is observed for D3 tool steel which tempered at 160 ℃(54.1 HRC). In terms of microstructural analysis, primary carbide and pearlite in the as-received samples transform to tempered martensite and cementite after heat treatment process. From this research, for corrosion test, heat treated 440C SS sample tempered with 426 ℃possessed the excellent corrosion resistance with corrosion rate 0.2808 mm/year.