Analysis of the Thermal Dome Effect from Global Solar Radiation Observed with a Modified Pyranometer

조일성,이규태,지준범,김부요 한국광학회 2017 Current Optics and Photonics Vol.1 No.4

Solar radiation data measured by pyranometers is of fundamental use in various fields. In the field ofatmospheric optics, the measurement of solar energy must be precise, and the equipment needs to bemaintained frequently. However, there seem to be many errors with the existing type of pyranometer, whichis an element of the solar-energy observation apparatus. In particular, the error caused by the thermal domeeffect occurs because of the thermal offset generated from a temperature difference between outer domeand inner casing. To resolve the thermal dome effect, intensive observation was conducted using the methodand instrument designed by Ji and Tsay. The characteristics of the observed global solar radiation wereanalyzed by classifying the observation period into clear, cloudy, and rainy cases. For the clear-weathercase, the temperature difference between the pyranometer’s case and dome was highest, and the thermaldome effect was 0.88 MJ m-2 day-1. Meanwhile, the thermal dome effect in the cloudy case was 0.69MJ m-2 day-1, because the reduced global solar radiation thus reduced the temperature difference betweencase and dome. In addition, the rainy case had the smallest temperature difference of 0.21 MJ m-2 day-1. The quantification of this thermal dome effect with respect to the daily accumulated global solar radiationgives calculated errors in the cloudy, rainy, and clear cases of 6.53%, 6.38%, and 5.41% respectively.

복사전달과정에서 지형효과에 따른 기상수치모델의 민감도 분석

지준범,민재식,장민,김부요,조일성,이규태 한국기상학회 2017 대기 Vol.27 No.4

Numerical weather prediction experiments were carried out by applying topographic effects to reduce or enhance the solar radiation by terrain. In this study, χ and κ(φo, θo) are precalculated for topographic effect on high resolution numerical weather prediction (NWP) with 1 km spatial resolution, and meteorological variables are analyzed through the numerical experiments. For the numerical simulations, cases were selected in winter (CASE 1) and summer (CASE 2). In the CASE 2, topographic effect was observed on the southward surface to enhance the solar energy reaching the surface, and enhance surface temperature and temperature at 2 m. Especially, the surface temperature is changed sensitively due to the change of the solar energy on the surface, but the change of the precipitation is difficult to match of topographic effect. As a result of the verification using Korea Meteorological Administration (KMA) Automated Weather System (AWS) data on Seoul metropolitan area, the topographic effect is very weak in the winter case. In the CASE 1, the improvement of accuracy was numerically confirmed by decreasing the bias and RMSE (Root mean square error) of temperature at 2 m, wind speed at 10 m and relative humidity. However, the accuracy of rainfall prediction (Threat score (TS), BIAS, equitable threat score (ETS)) with topographic effect is decreased compared to without topographic effect. It is analyzed that the topographic effect improves the solar radiation on surface and affect the enhancements of surface temperature, 2 meter temperature, wind speed, and PBL height.

소규모 태양열온수기의 에너지 절감비용과 오염물질 방출 저감에 따른 회피비용 분석

김혜원(Hye Won Kim),홍준(Jun Hong),고명진(Myeong Jin Ko),김용식(Yong Shik Kim),김병선(Byung Seon Kim) 대한설비공학회 2017 대한설비공학회 학술발표대회논문집 Vol.2017 No.6

A number of researches on solar water heating systems have focused on the energy simulation program such as TRNSYS, T-SOL, F-CHART and POLYSUN. However analysis using a energy simulation program is difficult to purchase and spread generally. Therefore, a method for roughly evaluating the energy performance of a solar water heating system is required. Accordingly, the study on efficiency of the solar water heaters in six representative regions of Korea, was reported using the concept of ‘effective solar radiation’, which is the actual solar radiation used to manage the daily hot water load of the region. In this study, based on the preceding research, the energy savings of solar water heaters and the avoidance cost of the pollutants reduction were analyzed. Therefore, it is shown that the economic efficiency of the solar thermal system is more improved if the environmental cost, which is not taken into consideration in the previous economic evaluation, is added to the cost of avoiding the pollutants.

지형 효과를 고려한 지표면 태양광 분포

지준범,조일성,이규태,최영진 한국지구과학회 2011 한국지구과학회지 Vol.32 No.2

지형 효과가 포함된 태양복사 모델(GWNU)을 이용한 한반도의 태양광 자원지도를 개발하였다. 태양복사 모델의입력 자료는 위성 관측 자료(MODIS, OMI, MTSAT-1R)와 수치 모델(RDAPS) 자료를 사용하였으며 특히 고해상도 지형 자료를 이용하여 지형 효과에 따른 한반도의 지표면 태양광 변화를 계산하였다. 계산 결과를 월 및 연 누적하여 분석하였을 때 여름철은 태양 고도각이 높아 지형 효과에 영향이 10% 이하로 적은 반면 겨울철은 20% 이상의 큰 차이가 나타났다. 또한 4 km 해상도의 지표면 태양광의 경우보다 1 km 해상도의 경우 지형 효과 포함에 따른 태양광 차이가 약 2배 정도 크게 나타났다. 즉 지표면에 도달하는 태양광을 정확히 모델링하기 위해서는 입력 자료뿐만 아니라 정확하고 고해상도의 지형 자료가 필연적이며 지형효과는 더욱 뚜렷이 나타나 실제와 유사할 것이다. A photovoltaic energy map that included a topography effect on the Korean peninsula was developed using the Gangneung-Wonju National University (GWNU) solar radiation model. The satellites data (MODIS, OMI and MTSAT-1R)and output data from the Regional Data Assimilation Prediction System (RDAPS) model by the Korea Meteorological Administration (KMA) were used as input data for the GWNU model. Photovoltaic energy distributions were calculated by applying high resolution Digital Elevation Model (DEM) to the topography effect. The distributions of monthly accumulated solar energy indicated that differences caused by the topography effect are more important in winter than in summer because of the dependency on the solar altitude angle. The topography effect on photovoltaic energy is two times larger with 1 km resolution than with 4 km resolution. Therefore, an accurate calculation of the solar energy on the surface requires high-resolution topological data as well as high quality input data.

태양광 발전시스템의 발전 성능 분석

권순주,민영봉,최진식,윤용철 경상대학교 농업생명과학연구원 2012 농업생명과학연구 Vol.46 No.5

This study was performed to reduce the operating cost of a greenhouse by securing electric energy required for greenhouse operation. Therefore, it experimentally reviewed the performance analysis of photovoltaic system in terms of maximum amount of generated electric power based on the amount of horizontal solar radiation during daytime. That is to say, the maximum solar radiation at 300, 400, 500, 600, 700, 800 and 900 W. m-2, respectively. The amount of momentary electric power of the photovoltaic system at any was about 970 W and we found that the momentary efficiency of the photovoltaic system that was used for this experiment was 97%. In the case of this system, we found that electric power will be generated when amount of horizontal solar radiation is more than 200 W. m-2, at minimum. If the amount of horizontal solar radiation is increased, the maximum power generation is also increased. At that time, the maximum efficiencies were 30, 78, 86 and 90%, respectively. However, when the amount of insolation was about 800 W. m-2, the maximum power generation tended to be lower than 700 W. m-2. The efficiency which caused the maximum electric power was decreased to less than 97% of the momentary generated electric power. When the total amounts of horizontal solar radiation per day were 3.24, 8.10, 10, 90, 12.70, 14.33, 19.53 and 21.48 MJ․m-2 respectively, the total amounts of power energy were 0.03, 0.40, 3.60, 4.37, 4.71, 4.70 and 4.91 kWh. And it represented that the total amounts of power energy were either decreased or increased a bit on the border between some solar radiations. The temperature at the back of the array tended to be higher than the temperature at the front but it demonstrated an increased when the amount of solar radiation increased. In the case of this system, the performance of the module in terms of degradation has not been shown yet. 본 연구에서는 온실 운영에 필요한 전력량을 확보함으로서 온실경영비 절감을 목적으로 수평면 일사량, 즉 최대 일사량이 각각 300, 400, 500, 600, 700, 800 및 900 W․m-2 정도인 날을 기준으로 최대 발전량과 시간의 경과에 따른 태양광발전시스템의 성능을 시험적으로 검토하였다. 태양광발전시스템의 순간 발생전력은 약 970 W정도로서 본 시험에 이용한 태양광발전시스템의 순간 효율은 97% 정도인 것을 알 수 있었다. 본 시스템의 경우, 수평면 일사량이 최소한 200 W․m-2 이상이 되어야 전력이 발생되는 것을 알 수 있었다. 수평면 일사량이 증가하면 최대 발생전력도 증가하였고, 이 때 최대효율은 각각 약 30, 78, 86 및 90% 정도였다. 그러나 일사량이 약 800 W․m-2정도가 되면 최대 발생전력은 오히려 700 W․m-2 보다 감소하는 경향이 있었다. 최대전력이 발생되는 효율도 순간 발생전력 97%정도보다 감소하였다. 그리고 일별 수평면 총일사량이 각각 3.24, 8.10, 10.90, 12.70, 14.33, 19.53 및 21.48 MJ․m-2정도 일 때, 총 발생전력량은 각각 0.03, 0.40, 3.60, 4.37, 4.71, 4.70 및 4.91 kWh정도로서 어느 일사량을 경계로 총 발생전력량은 조금 감소하거나 증가하였다. 어레이 배면온도가 전면온도보다 높게 나타나는 경향이 있지만, 일사량이 증가하면 어레이 배면온도도 증가하는 것으로 나타났다. 본 시스템의 경우, 아직까지 모듈의 성능저하는 없는 것으로 나타났다.

비행고도 상에서의 우주방사선 관측 및 모델 비교

이원형,김지영,장근일 한국항공운항학회 2018 한국항공운항학회지 Vol.26 No.2

High-energy charged particles are comprised of galactic cosmic rays and solar energeticparticles which are mainly originated from the supernova explosion, active galactic nuclei,and the Sun. These primary charged particles which have sufficient energy to penetrate theEarth's magnetic field collide with the Earth's upper atmosphere, that is N2 and O2, andcreate secondary particles and ionizing radiation. The ionizing radiation can be measured atcommercial flight altitude. So it is recommended to manage radiation dose of aircrew asworkers under radiation environment to protect their health and safety. However, it is hardto deploy radiation measurement instrument to commercial aircrafts and monitor radiationdose continuously. So the numerical model calculation is performed to assess radiationexposure at flight altitude. In this paper, we present comparison result between measurementdata recorded on several flights and estimation data calculated using model and examine thecharacteristics of the radiation environment in the atmosphere.

인천국제공항 제2여객터미널 대공간의 일사를 고려한 냉방기 실내온도, 기류분포 시뮬레이션 분석 연구

윤재옥(Yoon, JaeOck),이주희(Lee, Juhee) 대한건축학회 2020 대한건축학회논문집 Vol.36 No.8

Incheon International Airport(IIA) Terminal 2 is a large and high-rise building. In particular, the ceiling height of the Great Hall Level 5 in the center of the IIA Terminal 2 is more than 26m. That is a huge atrium with 4 floors open in some spaces, from Level 2 to Level 5. The height of that space is more than 41m. It is not easy to composite comfort indoor environments in the huge space because of temperature stratification. The CFD(Computational Fluid Dynamics) simulation is the best method at the planning stage to predict indoor temperature and airflow distribution in a large space. The purpose of this study is to persue indoor environments comfort, indoor temperature and air velocity, for the occupant area(Z=1.5m) in the Great Hall. We investigated whether the air condition is comfortable in summer, considering interior heat gains and solar radiation. It was predicted using the turbulence CFD simulation with commercial code STAR CCM+in the large space. A steady-state CFD simulation was performed, and the cooling peak time was set to 1 PM by calculating the MEP cooling load. After analyzing the results of simulation with the initial plan of MEP, we identified the problems and suggested six improvements. 1) Adding inlets near the north curtain wall at level 5. 2) Adding inlets around the sunken space of Level 4. 3) Changing the air supply tower to a normal air supply(SA) of indoor booth. 4) Adding outlets(RA). 5) Adding and relocating SA, RA to Level 2, 3. 6) SA extraction angle adjustment. The results of CFD simulations are presented in this paper. The indoor temperature and air velocity distributions of final plan was simulated and comfortable environment conditions were confirmed.

통신해양기사위성 통신 탑재체의 우주 방사선 환경 모사 및 영향 추정

김성준(Sung-Joon Kim),선종호(Jongho Seon),우형제(Hyung-Je Woo),최장섭(Jang-Sup Choi) 한국항공우주학회 2006 韓國航空宇宙學會誌 Vol.34 No.11

통신해양기상위성의 통신 탑재체가 겪게 될 우주 방사선 환경을 포획된 입자, 태양 양성자 그리고 우주선으로 구분하여 각각 NASA AP8/ AE8 모델, JPL91 모델, 그리고 NRL CREME 모델을 사용하여 전산 모사 하였다. 이러한 우주 방사선 환경이 위성 내 통신 탑재체에 미치는 영향을 추정하기 위해 총 이온화 방사선 효과의 분석에 필요한 Dose-Depth 곡선 및 단일사건효과 발생률 계산에 필요한 LET 스펙트럼 구하였다. 통신 탑재체 내의 각 장치별 차폐 효과 차이를 고려한 총 이온화 방사선 효과의 예측을 위해서 기계 구조 모델을 만든 후 구형 분할 방법을 적용하였다. 이를 통해 통신 탑재체 내각 장치의 위치별 총 이온화 방사선 효과를 예상하였으며 동일한 외부 방사선 환경에 대해서 차폐 효과에 따라 최고 8배까지 방사선 효과가 다르게 나타났다. Space radiation environment for COMS is simulated by NASA AP8/ AE8, JPL91 and NRL CREME models, respectively for trapped particle, solar proton and cosmic-ray. The radiation effects on electronic devices in communication payload are also estimated by using simulation results. Dose-depth curve and LET spectrum are calculated for estimating total ionizing dose(TID) effect and single event effect(SEE) respectively. Spherical sector method is applied to dose estimation at each position in the units of communication payload to consider shielding effect of platform and housing. Total ionizing dose at each position varies by 8 times through shielding effect under the same external space radiation environment.

고에너지 전자빔을 이용하여 저궤도 인공위성의 실리콘 태양센서의 내방사선 특성 연구

정성인(Sung In Chung),이재진(Jae Jin Lee),이흥호(Heung Ho Lee) 대한전자공학회 2008 電子工學會論文誌-SD (Semiconductor and devices) Vol.45 No.3

본 논문은 고에너지 전자빔을 이용하여 저궤도 인공위성의 실리콘 태양센서의 내방사선 특성 변화를 분석하였다. 일반적으로 저궤도를 선회하는 위성은 반알렌대를 통과하며, 이 안에서 주기적인 운동으로 남극과 북극을 이동하는 하전입자에 의해 전자부품이 쉽게 손상되고 수명이 단축되는 등 악 영향을 받고 있다. 특히 방사선에 의한 SEU (Single Event Upset) 등은 인공위성에 탑재된 반도체 소자의 오동작 유발의 원인이 되고 있다. 본 논문은 한국원자력 연구원의 고에너지 (300 keV ∼ 1MeV) 전자빔 조사장치를 이용하여 태양전지에 전자빔을 조사하고 이 때 변화되는 각각의 파라미터들에 대한 값을 측정하고자 한다. 이러한 연구는 저궤도 인공위성에서 전력을 생산하기 위해서 사용하는 전력용 태양 전지의 방사능 영향을 이해하는데도 많은 영향을 줄 수 있을 것으로 기대된다. This paper analyzes on the radiation effect of silicon solar cells in a low Earth orbit satellite by using high energy electron beams. Generally, the satellite circling round in a low orbit go through Van Allen belt, in which electronic components are easily damaged and shortened by charged particles moving in a cycle between the South Pole and the North Pole. For example, Single Event Upset (SEU) by radiation could cause electronic devices on satellite to malfunction. From the ground experiment in which we used the high energy electron beam facility at Korea Atomic Energy Research Institute (KAERI), we tried to explain sun sensor degradations on orbit could be caused by high energy electrons. While we focused on the solar cells used for light detectors, We convince our research also contributes to understand the radiation effect of solar cells generating electric powers on satellites.

솔라패널을 이용한 라디오존데 온도센서의 일사보정

박명석(Myeong-Seok Park),이진욱(Jin-Wook Lee),정세진(Se-Jin Jeung),장재원(Jea-Won Jang) 한국기상학회 2019 대기 Vol.29 No.3

For the upper air observations, a temperature measurement using radiosonde is a common method, and the compensation of solar radiation effects in the radiosonde temperature sensor is an important factor. In this paper, we present various experiments and compensation methods of the radiosonde temperature sensor to overcome the errors caused by the movement of the radiosonde rotation, etc. The methods and procedures of this study are as follows. First, we used the solar simulator to analyze the temperature variation and solar effect of the temperature sensor in the radiosonde according to the insolation. We also analyzed the temperature variation and solar effect of the temperature sensor according to the incident angle between the solar simulator and radiosonde. Second, we measured and analyzed solar radiation absorbed by solar cells attached to radiosonde. Third, we present combined compensate solution of the first and the second experiment results, to overcome errors caused by insolation effects in the radiosonde temperature sensors. Fourth, we compared that the reference temperature in similar environment with the upper air conditions, to verify the new radiated compensation performance of the radiosonde temperature sensor. Finally, the radiosonde fabricated in this study was raised to the atmosphere, and the laser correction algorithm proposed through experiments was reviewed. As a result of the radiosonde SRS-10 produced in this study, the temperature deviation from Vaisala RS92 was 0.057℃ in nighttime observation, 0.17℃ in daytime observation, It is expected that the GRUAN under WMO will be able to obtain a high test rating of 5.0.