• 대한기계학회:학술대회논문집
• /
• 대한기계학회 2007년도 춘계학술대회B
• /
• pp.3389-3394
• /
• 2007

Characteristics of heat transfer and pressure drops of fills for solar tower volumetric air receivers are experimentally investigated with the material and the thickness. The volumetric air receiver considered in this paper consists of a ceramic tube and fills are inserted in the ceramic tube. Air is used as the working fluid. Two materials, which are a honeycomb(diameter: 100mm, thickness: 30mm) and laminated mesh(diameter: 100mm, thickness: 1mm), are considered as the fills. In order to investigate the characteristics of heat transfer of fills, this volumetric air receiver is heated by an electric heater and air temperatures in ceramic tube are measured. Also, the radiative shields are installed to measure the only air temperature. In addition, the pressure losses are measured with the thickness of fills while the air goes through the fills inserted in an acrylic tube. The flow becomes turbulent and fully developed in front of the fills. The results show that the heat transfer and pressure drop characteristics of the laminated mesh are superior to those of the honeycomb.

• 한국태양에너지학회 논문집
• /
• 제33권1호
• /
• pp.1-6
• /
• 2013

It is difficult to avoid measurement errors caused by the shading effect of the meteorological tower, which is used for wind resource assessment according to the IEC Standard. This paper presents a validation of the computational flow analysis results by comparing the results with the wind tunnel experiment conducted for Reynolds numbers in the $10^4$ to $10^5$ range, for the preparation of a database for use in an automatic method of correcting met-tower shading errors. A three-dimensional simulation employing the MP (Modified Production) $k-{\varepsilon}$ turbulence model predicted a wind speed deficit in the wake region according to minimum wind speed ratio, within an MAE (Mean Absolute Error) of 2.4%.

• 한국태양에너지학회 논문집
• /
• 제34권2호
• /
• pp.60-65
• /
• 2014

A meteorological(met) tower is the first structure installed during the planning stages of offshore wind farm. The purpose of this paper is to design the met tower with tripod bucket type support structure and to install the sensors. The support structure consist of a central steel shaft connected to three cylindrical steel suction buckets which is more cheaper than monopile or jacket type. And the remote wind condition sensors and marine monitoring equipment, including adcp, pressure type tide gauge, wave height sensors, and scour sensors, remote power supply are installed. The manufactured met tower constructed on sea area which is in front of Gasa island. All of functions of met tower showed normal operation conditions and the wind data got by remote data collection system successfully.

• 대한기계학회논문집B
• /
• 제36권3호
• /
• pp.277-284
• /
• 2012

타워형 태양열 발전용 체적식 공기흡수기의 열전달 성능 해석을 수행하였다. 타당한 관련문헌에 기초하여 채널 한 개의 벽과 공기 온도분포를 지정된 기하학적 크기와 입력조건에서 예측 할 수 있는 계산과정들이 제시되었다. 더 나아가서 흡수기 유용도의 수학적 모델이 온도프로파일 해석을 통해 유일하게 제시되었다. 흡수기 재질은 실리콘 카바이드이다. 공기 흐름을 유도하는 정사각형 직선채널 크기는 $2mm(W){\times}2mm(H){\times}0.2mm(t){\times}320mm(L)$이며, 모듈 한 개에는 225 개의 채널이 성형되었다. 일정한 일사량 및 공기유량 가정하에서 채널과 모듈 수의 변화에 따른 열전달량, 온도분포 및 유용도 추이가 제시되었다. 태양열 발전에 응용하기 위해서는 흡수기 출구 공기온도가 $700^{\circ}C$ 이상에 도달하여야 한다. 본 수치모델은 200 kW 급 타워형 태양열 공기흡수기의 설계에 사용되었으며, 지정된 기하학적 조건과 입력조건에서 요구되는 열전달 성능을을 만족하는 모듈 수를 얻을 수 있었다.

• 대한설비공학회:학술대회논문집
• /
• 대한설비공학회 2007년도 하계학술발표대회 논문집
• /
• pp.171-171
• /
• 2007

• 대한원격탐사학회지
• /
• 제29권1호
• /
• pp.137-149
• /
• 2013

표면도달일사량은 태양과 지구에너지시스템을 이해하는데 중요하며, 대기-지표면의 흐름, 농업 생산량, 태양발전에 필요한 에너지 연구 등과 같은 많은 분야에 활용되고 있는 중요한 변수이다. 대부분의 태양에너지는 지상관측지점에서 관측하는 경우가 많이 있지만, 공간적인 분포를 판단하기에는 한계성을 지니고 있다. 이에 반해 인공위성을 활용한 원격탐사 기법은 지속적인 자료 제공과 더불어 광역범위의 공간적 분포를 파악하는 장점이 있다. 본 연구에서는 COMS 위성자료 중 표면도달일사량 (Solar Insolation, INS)의 정확성 판단하기 위해 플럭스 타워에서 측정된 지점 자료와의 비교, 검증을 실시하였다. 결론적으로 볼 때, 30분 간격의 자료와 일평균의 자료에서 높은 상관계수를 보임에 따라 천리안 위성자료의 한반도 적용가능성이 높다고 판단된다.

• 한국태양에너지학회:학술대회논문집
• /
• 한국태양에너지학회 2012년도 춘계학술발표대회 논문집
• /
• pp.299-304
• /
• 2012

In terms of plane structure, tower-type apartments have several disadvantages compared to flat-type apartments in the aspect of ventilation rate. Such disadvantages may not produce good indoor cooling effects with natural ventilation inside the heated apartments in hot summer days, so they may cause high energy consumption by an increase in cooling load. The purpose of this study is to investigate ways for improving the indoor thermal environment of tower-type apartments in summer by conducting quantitative evaluations of the airflow distribution in households.

• 한국신재생에너지학회:학술대회논문집
• /
• 한국신재생에너지학회 2007년도 춘계학술대회
• /
• pp.676-679
• /
• 2007

This paper describes an experiment facility to measure the circulation characteristics of a water/steam receiver at various heat fluxes. The natural circulation type receiver was considered in this study. The experiment facility was designed to satisfy circulation balance with an appropriate scale down. As a result, riser tube inner diameter was 7.4 mm and water circulation was 0.319 kg/s. Downcomer tube inner diameter by circulation balance was 9.52 mm and the quality was from 0 to 0.23.

• 한국태양에너지학회 논문집
• /
• 제24권4호
• /
• pp.27-33
• /
• 2004

Mechanical load measurements on blade and tower of Vestas 100 kW wind turbine has been reformed in Wollyong test site, Jeju island. The experimental procedure for the measurement of wind turbine loads, such as edgewise(lead-lag) bending moment, flapwise bending moment, and tower base bending moment, has been established. The test facilities consisting of strain-gauges, telemetry and T-Mon system are installed in the wind turbine. Strain gauges are on-site calibrated against load cell prior to monitoring the wind turbine loads. Using the test setup, the loads on the components are being measured and analysed for various external conditions of the wind turbine. A set of results for near rated wind speed has been presented in this paper.

• 천문학회보
• /
• 제36권2호
• /
• pp.95.2-95.2
• /
• 2011

The most powerful technique for deducing the magnetic structure of the Sun is spectro-polarimetry. Detailed measurements of the polarization signal of the spectral lines (Stokes vector) allow us to infer the physical conditions in the solar atmosphere prevailing during the line formation. Inversion codes are the main tool to extract this information from the Stokes spectra. This study will focus on measurements of the chromospheric He I 1083.0 nm triplet and the photospheric Si I 1082.7 nm line. A spectropolarimetric data set of sunspots, obtained with the German Vacuum Tower Telescope (VTT) at the Teide observatory on Tenerife, is analyzed using an inversion technique. We will introduce the German Vacuum Tower Telescope and the inversion code HeLix, and will show data sets that are analyzed by HeLix.