起伏地形下重庆市天文辐射的空间分布

在起伏地形下天文辐射分布式模型的基础上计算了重庆市各月的天文辐射的空间分布，详细分析了坡向和坡度对天文辐射分布的影响以及重庆市实际地形下天文辐射的空间分布。分析表明：1月和7月坡向和坡度对天文辐射的影响明显不同；地形对重庆天文辐射的分布影响显著，特别是太阳高度角较小的冬季。     

河北省起伏地形下高分辨率地外太阳辐射空间分布

基于起伏地形下地外太阳辐射的计算模型,综合考虑天文关系和地理、地形因素,利用河北省1:5万地理信息数据计算出100m×100m分辨率逐日地外太阳辐射的空间分布,进而分析了逐月、各季和全年的地外太阳辐射空间分布特征。结果表明:河北省年地外太阳辐射分布受太阳高度角和地形影响明显,由北向南整体呈递增趋势;实际地形下四季地外太阳辐射的大小排序为夏季>春季>秋季>冬季;冬季地外太阳辐射受地理、地形因子影响最明显,尤其表现在山区,向阳山坡(偏南坡)可为背阴山坡(偏北坡)的2～3倍,极端地外太阳辐射的差异达10倍以上,夏季地外太阳辐射受地形影响最小,极端地外太阳辐射差异只有1.5倍。     

山地光伏电站的近场阴影模拟研究

结合复杂山地地形条件下光伏组件的布置方案，基于PVsyst软件和Helios 3D软件建立了山地光伏电站三维近场阴影仿真模型，以模拟计算近场阴影遮挡损失修正系数；另外根据项目建设区域内实际的光伏组件倾角和光伏方阵方位角，结合光伏电站朝向替代计算，得到近场阴影遮挡损失修正系数；最后对3种计算方案得到的近场阴影遮挡损失修正系数与该项目实际值进行对比。研究结果表明：由于山地光伏电站项目建设区域地形中的坡度、坡向变化对光伏组件倾角、光伏方阵方位角存在影响，导致山地场景下的近场阴影遮挡损失修正系数比平地场景下的更大。提出的Helios 3D模拟计算方案和公式计算方案同样适用于其他山地光伏电站，可以对特定地形条件下光伏发电系统的阴影情况进行模拟，以评估光伏组件倾角、光伏方阵方位角对近场阴影遮挡损失修正系数的影响，可为精细化评估山地光伏电站中光伏组件布置方案对近场阴影遮挡损失修正系数的影响程度提供合理的分析、研究方案。     

一种计算无辐射资料地区最佳倾角的研究

构建基于分布较广的常规气象台站的日照百分率数据来计算水平面太阳辐射的模型,拟合结果表明模型精度较高。在此基础上使用空间插值技术得到全国范围内水平面太阳辐射,使用MODIS反照率产品获取地形反射辐射,之后依据各向异性辐射模型计算光伏阵列面太阳辐射,循环寻优生成最佳倾角的全国空间连续分布图。这套计算方法与结果可为包括无辐射观测记录地区在内的光伏阵列最佳倾角的确定提供科学参考。     

北京地区太阳紫外辐射的长期变化趋势及分析

对实际天气条件下北京地区1990年1月至1992年8月太阳辐射预测资料进行了详细分析。得到实际天气条件下到达地面的太阳紫外辐射的计算公式。结果表明,计算值与预测值吻合得比较好,利用该式计算了北京地区1979年1月-1996年6月的太阳紫外辐射,讨论了1979-1996年北京地区太阳紫外辐射的变化趋势及不同因子（臭氧、水汽、气溶胶等）对太阳紫外辐射的影响。     

基于数字高程模型的漳浦样区太阳天文日辐射模拟

以地形特征、经纬度位置等作为影响太阳辐射空间分布差异的变量,以漳浦样区为研究区域,在地理信息系统支持下建立样区DEM和太阳天文日辐射值计算模型,探求小区域尺度上地形对太阳天文日辐射空间分布的影响。结果表明:地形对漳浦样区太阳天文日辐射空间分布的影响相当显著,基本上是山谷小、山脊大、阴坡小、阳坡大,高辐射量值主要出现在阳坡。该方法可以快速地获取较为精确的小区域太阳天文日辐射空间分布值,但由于该模型没有考虑云的影响和DEM精度,计算值与实际太阳辐射存在一定偏差,今后研究的方向是以遥感影像为数据源考虑地面状况和云的影响,以期提高模拟精度。     

福建太阳总辐射和地面辐射平衡的分布

首先利用福州市的辐射观测资料，建立计算太阳总辐射的经验公式，并计算福建省各市、县的太阳总辐射的年、月平均辐照度。然后利用地区代表站的地面反射率，求得福建省各月、年地面所吸收的太阳辐射能的分布。再利用地面温度、气温、水汽压和总云量、计算得出福建省各地的地面有效辐射的月、年平均辐照度。最后得出福建省各月、年地面辐射平衡的分布。     

华北平原北部太阳辐射及地表辐射平衡特征——基于河北固城站的试验观测研究

利用位于河北定兴县的中国气象局固城生态与农业试验站2005年7月～2007年2月期间观测的太阳辐射各分量的资料,详细分析了该站太阳辐射及地表反射的基本特征.分别对到达地表的太阳总辐射、地面反射短波辐射、地表反射率、净辐射、光合有效辐射和紫外辐射(UV-B)的日、年变化特征进行了分析,揭示了该地区的辐射平衡特征.同时分析并给出了光合有效辐射和紫外UV-B辐射占太阳总辐射比值的变化规律.     

冷辐射板吸收太阳辐射的特性研究

为计算辐射空调系统中冷辐射板吸收太阳辐射能的大小及比例,在分析室内太阳光线传播的基础上,提出采用一种线性方程的方法.结果表明,以本文房间为例,冷辐射板吸收的太阳辐射能的大小以及比例在夏至日表现为正午最小,冷辐射板所吸收的太阳辐射能理论上最大能达到32 W/m2,吸收系数在0.13～0.28之间变化.冷辐射板所吸收的太阳...     

温室内太阳净辐射分配及计算

针对温室内存在气体辐射问题,应用辐射相关知识,推导出温室各内表面对太阳净辐射的吸收份额,并给出了温室内气体吸收率的计算方法。针对睛天和阴天的不同太阳辐射特性,提出了相应的理论计算方法,为温室内能量计算提供了理论依据。     

区域复杂地形晴日太阳辐射估算研究

为改进复杂地形区区域地表接收太阳入射辐射的算法,基于数字高程模型、气象数据与遥感数据,分直接辐射、来自天空的散射辐射及来自周围地形的反射辐射3部分对海河流域2001—2019年区域地表接收的晴日太阳辐射日总量进行估算与分析。经验证,模拟的晴日太阳入射辐射日通量与实测数据吻合度较高,相关系数约为0.9,区域不同地形接收的太阳入射辐射空间差异明显,结果在可接受精度范围内,此估算方法可为山区太阳能的合理利用提供科学基础。     

Solar radiation and shadow modelling with adaptive triangular meshes

In this work, we propose a numerical model for generating solar radiation maps with the use of 2-D adaptive meshes of triangles. These triangulations are constructed by using a refinement/derefinement procedure in accordance with the variations of terrain surface orography and albedo. This discretization has the advantage of defining the terrain characteristics with a minimum number of points, which reduces the computational cost for a given accuracy. Moreover, the model takes into account the effect of shadows for each time step, which are detected by analysing the crossing of the trajectory of the shaft of light with the triangles of the mesh. Thus, the solar radiation is first computed for clear-sky considering the different components of radiation, that is, beam, diffuse and reflected radiations. From the results of clear-sky radiation, the real-sky radiation is computed daily in terms of the clear-sky index. The maps of clear-sky index are obtained from a spatial interpolation of observational data that are available for each day at several points of the zone under consideration. Finally, the solar radiation maps of a month are calculated from the daily results. We illustrate the performance of the model with a numerical experiment related to an episode on the island of Gran Canaria.     

晴天太阳辐射模型的优化计算

对几种最常用的晴天太阳辐射模型进行对比计算研究。通过实验验证,第一种模型较符合实测值,编制了利用了该种模型计算任何地方任何一天的任何一段时间（包括整个白天时间段）内水平表面或朝南倾斜表面（包括竖直表面）上的太阳辐射能的计算程序软件。理论计算与实验值均在5%以内,完全能满足一般太阳能工程和科学研究的需要。     

Estimation of solar radiation over Cambodia from long-term satellite data

In this work, monthly average daily global solar irradiation over Cambodia was estimated from a long-term satellite data. A 14-year period (1995–2008) of visible channel data from GMS5, GOES9 and MTSAT-1R satellites were used to provide earth-atmospheric reflectivity. A satellite-based solar radiation model developed for a tropical environment was used to estimate surface solar radiation. The model relates the satellite-derived earth-atmospheric reflectivity to absorption and scattering coefficients of various atmospheric constituents. The absorption of solar radiation due to water vapour was calculated from precipitable water derived from ambient relative humidity and temperature. Ozone data from the TOMS and OMI satellite data were employed to compute the solar radiation absorption by ozone. The depletion of radiation due to aerosols was estimated from the visibility data. Five new solar radiation measuring stations were established at Cambodian cities, namely Siem Reap (13.87°N, 103.85°E), Kompong Thom (12.68°N, 104.88°E), Phnom Penh (11.55°N, 104.83°E), Sihanouke Ville (10.67°N, 103.63°E) and Kampot (10.70°N, 104.28°E). Global solar radiation measured at these stations was used to validate the model. The validation was also carried out by using solar radiation measured at four Thai meteorological stations. These stations are situated near the Cambodian border. Monthly average daily global irradiation from these stations was compared with that calculated from the model. The measured and calculated irradiation is in good agreement, with the root mean square difference of 6.3%, with respect to the mean values. After the validation, the model was used to calculate monthly average daily global solar irradiation over Cambodia. Based on this satellite-derived irradiation, solar radiation maps for Cambodia were generated. These maps show that solar radiation climate of this country is strongly influenced by the monsoons. A solar radiation database was also generated for solar energy applications in Cambodia.     

Wind loads on heliostats and photovoltaic trackers of various aspect ratios

For the layout of solar trackers the wind loads on the structure have to be known. They can be calculated by using wind load coefficients given in literature. But so far these values are only valid for aspect ratios of the panel (width to height) of about 1.0. Therefore the wind load coefficients for heliostats of aspect ratios between 0.5 and 3.0 were determined to close this gap.As solar trackers are exposed to the turbulent atmospheric boundary layer the turbulence of the approaching flow has to be modeled. As a reliable method at reasonable cost wind tunnel measurements were chosen. Solar trackers of 30 m² panel size were investigated at a model scale of 1:20. Wind direction and elevation angle of the panel were varied to investigate especially the constellations at which the highest wind loads are expected (critical load cases). By spires and roughness elements a wind profile and a turbulence intensity of the modeled wind according to typical sites for solar trackers were achieved. The loads were measured by a high frequency force balance placed underneath the models. Additionally measurements of the pressure distribution on a panel with aspect ratio of 1.2 were performed to better understand the effects that lead to the peak values of the wind load coefficients.A significant impact of the aspect ratio was measured. For the critical load cases the aspect ratio dependencies of the accordant peak wind load components were determined. By these the peak wind loads on solar trackers of varies aspect ratios can be calculated.Regarding the single solar tracker components the main results are: Higher aspect ratios are advantageous for the dimensioning of the foundation, the pylon and the elevation drive but disadvantageous for the azimuth drive.     

高空飞艇薄膜太阳电池内辐射量计算研究

修正了任一方向的平面内太阳辐射计算模型,使之适用于编程计算各种倾角和方位角平面上的太阳辐射。在曲面上进行网格划分,生成若干个小平面,推导出平面法向量与倾角和方位角之间的关系式,逐个计算每个小平面上太阳辐射量,叠加后近似代替整个曲面上的太阳辐射量。运用此方法计算了高空飞艇的薄膜太阳电池上辐射量,并与此薄膜太阳电池在水平投影面内辐射量计算结果进行比较。结果表明,用水平投影面内辐射量代替薄膜太阳电池内辐射量有很大的偏差。因此,在高空飞艇能源系统性能详细分析阶段需要使用曲面内太阳辐射量计算模型,为随后的光电转换与能源系统计算提供准确的太阳辐射数据。     

Calculation of Escaped Solar Energy in Glazing Façade Buildings

ABSTRACT

In building's cooling load calculation, solar heat gain through transparent envelope is calculated by using solar heat gain coefficient which is a thermal performance parameter of window. In traditional buildings, window-wall ratio is small so it's is assumed that the incoming solar radiation can't escape through the window again. But this hypothesis isn't suitable for glazing façade buildings. To calculate the escaped solar energy ratio, a solar radiation model is established on the basis of radiosity-irradiation method and calculated by using the commercial software of Matlab. The impact of time, room geometric dimensioning and absorptance of interior surfaces are evaluated. The numerical calculation results show that the escaped solar radiation ratio varies according to solar radiation incident angle in different times and its maximum value is 8.85% in summer solstice; compare to the width, the depth and height of the room affect the ratio significantly; the reflectance of the floor has greater impact on the escaped solar energy ratio than of other internal surfaces. Finally a fitting formula of escaped solar energy ratio is provided as a function of the ratio between the window area and the internal surface area and of the internal surfaces' absorptance.     

Correlations for estimating solar radiation using sunshine hours and temperature measurement in Osogbo,Osun State,Nigeria

In this study, the global solar radiation on horizontal surface in Osogbo, Osun state, Nigeria was analyzed using 11-year data (1997–2007). Correlations using linear and quadratic expressions were developed to relate the global solar radiation on horizontal surface based on relative sunshine hours and temperature measurements for evaluating the monthly average daily global solar radiation. The calculated monthly clearness index values indicate that the prevailing weather condition in Osogbo is heavily overcast. All the developed quadratic correlations gave better correlation coefficients (0.834, 0.872 and 0.823 respectively) than the linear models. However, the Hargreaves and Samani related based quadratic model gave the best among the three developed quadratic expressions and is therefore suggested for estimating the monthly global radiation in this site and its surroundings.