共查询到20条相似文献,搜索用时 125 毫秒
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支持向量机方法在太阳辐射计算中的应用 总被引:2,自引:0,他引:2
利用郑州1961~2000年的逐月曝辐量和有关气象数据,分析了曝辐量与气象因子的相关关系,应用支持向量机(SVM)方法,确定了影响逐月曝辐量的主要气象因子,建立了月曝辐量的支持向量机计算模型,为太阳能资源的评估方法提供了一种新的技术方法。用1961~2000年的逐月资料对郑州气象站的逐月曝辐量进行训练建模,用2001~2006的资料做评估效果检验,研究结果证明该方法适用于曝辐量的计算和太阳能资源的评估,可应用于同一气候区内无辐射观测的气象台站曝辐量的计算和太阳能资源评估,也可根据月气候预测进行月曝辐量的预估。 相似文献
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如何将水平面上太阳总辐射转换成倾斜面上太阳总辐射庄肃在太阳能利用中,为了使太阳能装置收集到更多的太阳辐射能,我们常将其倾斜安装,故需要计算到达倾斜面上的太阳总辐射能量。一般气象台站都有水平面上的太阳总辐射的观测资料,所以需将水平面上的太阳总辐射转换成... 相似文献
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太阳能集能器自动跟踪装置 总被引:7,自引:0,他引:7
太阳能集能器自动跟踪装置是由传感器、方位角跟踪机构、高度角跟踪机构和自动控制装置组成。自动跟踪装置驱动太阳能集能器 ,使集能器的主光轴始终与太阳光线相平行。当太阳光线发生倾斜时 ,传感器输出倾斜信号 ,指示执行器动作调整太阳能集能器的角度 ,直到太阳能集能器对准太阳 ,实现自动跟踪太阳的目的。在阴天或太阳光辐照度低于工作照度时自动关机 ,太阳光辐照度达到工作照度时自动开机。该装置适用于聚光式太阳能集能器、太阳能电池等需要跟踪太阳的装置 相似文献
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利用SMARTS模式计算晴天总辐射,充分考虑海拔高度和大气对太阳辐射的削弱作用,建立基于日照百分率的太阳能资源计算方程。以四川省为例的计算结果表明,该方法不仅物理意义更明确,并且计算误差明显降低;与实测值相比,7个辐射台站年总辐射曝辐量的相对误差低于7%,月总辐射曝辐量中有约67%的相对误差介于[-5%,5%]之间;与初始值采用天文辐射的方法相比,无论是相对误差的量值还是离散程度,均降低一半以上,有效降低了类似峨眉山站的"孤点"的相对误差。 相似文献
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太阳能资源评估是太阳能资源开发利用的基础,针对我国现行的太阳能资源评估标准以长期观测数据为稳定性分析对象,无法满足电力行业对太阳能资源变化特性的实际要求,提出一种太阳能资源日变化分析方法,并以北京地区为例,首先研究了不同时间尺度太阳能资源变化特征,再结合光伏电站接入电网的相关规定,利用太阳辐射日变化分析参数K′分析了晴天、多云、阴雨等典型天气条件和连续30d的太阳能总辐射日变化情况。结果表明,太阳能资源日变化分析方法能够反映1d中太阳能资源的稳定程度,对光伏发电的规划和设计具有一定的参考意义。 相似文献
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The performance of a photovoltaic (PV) panel is affected by its orientation and its tilt angle with the horizontal plane. This is because both of these parameters change the amount of solar energy received by the surface of the PV panel. A mathematical model was used to estimate the total solar radiation on the tilted PV surface, and to determine optimum tilt angles for a PV panel installed in Sanliurfa, Turkey. The optimum tilt angles were determined by searching for the values of angles for which the total radiation on the PV surface was maximum for the period studied. The study also investigated the effect of two-axis solar tracking on energy gain compared to a fixed PV panel. This study determined that the monthly optimum tilt angle for a PV panel changes throughout the year with its minimum value as 13° in June and maximum value as 61° in December. The results showed that the gains in the amount of solar radiation throughout the year received by the PV panel mounted at monthly optimum tilt angles with respect to seasonal optimum angles and tilt angel equal to latitude were 1.1% and 3.9%, respectively. Furthermore, daily average of 29.3% gain in total solar radiation results in an daily average of 34.6% gain in generated power with two-axis solar tracking compared to a south facing PV panel fixed at 14° tilt angle on a particular day in July in Sanliurfa, Turkey. 相似文献
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Recent interest in the application of PV in buildings throughout northern Europe has developed a need for long-term records of the solar resource in urban situations. Previous records have usually been collected from locations quite remote from city centre sites and, furthermore, at hourly sampling frequencies which are not rapid enough for photovoltaic applications. The installation of a photovoltaic monitoring station in a city centre in the north-east of England is described. Weather monitoring instruments were installed to measure ambient temperature, wind speed and direction, relative humidity and solar irradiance. Four types of photovoltaic modules are mounted on the rig in typical buiding orientations in order to assess their performance with respect to PV cladding applications. Preliminary investigations have shown that the electricity generated by PV cladding on vertical surfaces experiences much less seasonal variation than that on a horizontal surface. The performance of north and south facing modules has also been compared and this has shown that the north facing modules generate reasonably large amounts of electricity, particularly during the summer months. The proportion of diffuse irradiance on a north facing surface has been studied and quantified for various amounts of global horizontal irradiance. Analysis of the cadmium telluride modules has confirmed a better response to diffuse irradiance than the silicon modules and records of the amorphous silicon module show no evidence of cell degradation. 相似文献
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《全球能源互联网(英文)》2018,1(4):460-466
A key design parameter for fixed grid-connected photovoltaic (PV) arrays, the optimal tilt angle, does not only depend on the geographic location but is also directly affected by atmospheric conditions. In this paper, long-term variations of solar radiation (i.e. global solar irradiance, direct horizontal irradiance, diffuse irradiance, and ratios of direct and diffuse irradiance) in Beijing are considered to determine their effect on the optimal tilt angle for a fixed grid-connected PV array. We found that there is a declining trend in global solar irradiance over the past 55 years, mainly caused by the decreased direct horizontal irradiance. In contrast, the decline of diffuse irradiance is not obvious, leading to a considerable decrease in the direct irradiance ratio and consequent increase in the diffuse irradiation ratio. Likewise, the long-term optimal tilt angle shows a downward trend. Compared with the optimum in the 1960s, the optimal tilt angle has decreased by 2° in 2011–2015. These results suggest that the declining trend in the optimal tilt angle is mainly caused by the decrease in direct irradiance ratio, which is highly related to atmospheric conditions. Therefore, the design and construction of PV power stations must consider the variations of atmospheric conditions and solar irradiance to determine the optimal tilt angle. 相似文献
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Solar radiation is a key factor determining electricity produced by photovoltaic (PV) systems. This paper presents a solar radiation database of Europe developed in the geographical information system, and three interactive web applications providing an access to it. The database includes monthly and yearly average values of the global irradiation on horizontal and inclined surfaces, as well as climatic parameters needed for an assessment of the potential PV electricity generation (Linke atmospheric turbidity, the ratio of diffuse to global irradiation, an optimum inclination angle of modules to maximize energy yield). In the first web application, a user may browse radiation maps and query irradiation incident on a PV module for different inclination angles. The second application simulates daily profiles of irradiance for a chosen month and module inclination and orientation. The third web application estimates electricity generation for a chosen PV configuration. It also calculates optimal inclination and orientation of a PV module for a given location. The database and the applications are accessible at http://re.jrc.cec.ev.int/pvgis/pv/imaps/imaps.htm. 相似文献
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In the present study, performance results of two double axis sun tracking photovoltaic (PV) systems are analyzed after one year of operation. Two identical 7.9 kWp PV systems with the same modules and inverters were installed at Mugla University campus in October 2009. Measured data of the PV systems are compared with the simulated data. The performance measurements of the PV systems were carried out first when the PV systems were in a fixed position and then the PV systems were controlled while tracking the sun in two axis (on azimuth and solar altitude angles) and the necessary measurements were performed. Annual PV electricity yield is calculated as 11.53 MW h with 1459 kW h/kWp energy rating for 28 fixed tilt angle for each system. It is calculated that 30.79% more PV electricity is obtained in the double axis sun-tracking system when compared to the latitude tilt fixed system. The annual PV electricity fed to grid is 15.07 MW h with 1908 kW h/kWp for the double axis sun-tracking PV system between April-2010 and March-2011. The difference between the simulated and measured energy values are less than 5%. The results also allow the comparison of different solutions and the calculation of the electricity output. 相似文献
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Marcelo D. Cabezas Elian A. Wolfram Juan I. Franco Héctor J. Fasoli 《International Journal of Hydrogen Energy》2017,42(37):23455-23463
The use of solar photovoltaic (PV) is universally considered valuable for its renewable and clean nature; solar energy is especially important in regions far from urban centers and power distribution networks. It is known that the loss due to the latitude and the atmospheric layer is partially offset in very different annual distribution (i.e., by the long summer days) and in sparsely populated areas, because of the clearer atmosphere. Even with these assumptions, low temperatures (snow often combined with strong winds) and the effects of seasonality are difficult obstacles for the proper use of solar PV energy at high latitudes.In this work, both analytical and experimental data of the solar resource at Esperanza Base, Antarctica, are presented. The PV modules were installed in a vertical configuration and NW–NE orientation, which not only maximizes performance but also mitigates the adverse effects due to the latitude. In order to overcome the very asymmetric annual irradiance distribution, the use of a system of hydrogen production and accumulation, is proposed for effective energy storage.The results of two years of evaluation of PV potential at Esperanza Base show that duplicating the PV capture area in Esperanza allows to obtain the same total annual energy than the maximum acquired in Buenos Aires (PV module facing north with optimum tilt for solar capture).To effectively overcome discontinuity of solar energy and its sharp drop in four of the twelve months of the year an appropriate hydrogen vector system is proposed and analyzed. 相似文献
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In this paper, we show that photovoltaic (PV) energy yields can be simulated using standard rendering and ray-tracing features of Computer Aided Design (CAD) software. To this end, three-dimensional (3-D) sceneries are ray-traced in CAD. The PV power output is then modeled by translating irradiance intensity data of rendered images back into numerical data. To ensure accurate results, the solar irradiation data used as input is compared to numerical data obtained from rendered images, showing excellent agreement. As expected, also ray-tracing precision in the CAD software proves to be very high. To demonstrate PV energy yield simulations using this innovative concept, solar radiation time course data of a few days was modeled in 3-D to simulate distributions of irradiance incident on flat, single- and double-bend shapes and a PV powered computer mouse located on a window sill. Comparisons of measured to simulated PV output of the mouse show that also in practice, simulation accuracies can be very high. Theoretically, this concept has great potential, as it can be adapted to suit a wide range of solar energy applications, such as sun-tracking and concentrator systems, Building Integrated PV (BIPV) or Product Integrated PV (PIPV). However, graphical user interfaces of ‘CAD-PV’ software tools are not yet available. 相似文献
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Improved photovoltaic energy output for cloudy conditions with a solar tracking system 总被引:2,自引:0,他引:2
This work describes measurements of the solar irradiance made during cloudy periods in order to improve the amount of solar energy captured during such periods. It is well-known that 2-axis tracking, in which solar modules are pointed at the sun, improves the overall capture of solar energy by a given area of modules by 30-50% versus modules with a fixed tilt. On sunny days the direct sunshine accounts for up to 90% of the total solar energy, with the other 10% from diffuse (scattered) solar energy. However, during overcast conditions nearly all of the solar irradiance is diffuse radiation that is isotropically-distributed over the whole sky. An analysis of our data shows that during overcast conditions, tilting a solar module or sensor away from the zenith reduces the irradiance relative to a horizontal configuration, in which the sensor or module is pointed toward the zenith (horizontal module tilt), and thus receives the highest amount of this isotropically-distributed sky radiation. This observation led to an improved tracking algorithm in which a solar array would track the sun during cloud-free periods using 2-axis tracking, when the solar disk is visible, but go to a horizontal configuration when the sky becomes overcast. During cloudy periods we show that a horizontal module orientation increases the solar energy capture by nearly 50% compared to 2-axis solar tracking during the same period. Improving the harvesting of solar energy on cloudy days is important to using solar energy on a daily basis for fueling fuel-cell electric vehicles or charging extended-range electric vehicles because it improves the energy capture on the days with the lowest hydrogen generation, which in turn reduces the system size and cost. 相似文献
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Solar energy production is directly correlated to the amount of radiation received at a given location. Appropriate information on solar resources is therefore very important for designing and sizing solar energy systems. Concentrated solar power projects and photovoltaic tracking systems rely predominantly on direct normal irradiance (DNI). However, the availability of DNI measurements from surface observation stations has proven to be spatially too sparse to quantify solar resources at most potential sites. Satellite data can be used to calculate estimates of direct solar radiation where ground measurements do not exist. Performance of decomposition models of various complexity have been evaluated against one year of in situ observations recorded on the roof of the radiometric tower of the Royal Meteorological Institute of Belgium in Uccle, Brussels. Models were first evaluated on a hourly and sub-hourly basis using measurements of global horizontal irradiance (GHI) as input. Second, the best performing ground-based decomposition models were used to extract the direct component of the global radiation retrieved from Meteosat Second Generation (MSG) images. Results were then compared to direct beam estimations provided by satellite-based diffuse fraction models and evaluated against direct solar radiation data measured at Uccle. Our analysis indicates that valuable DNI estimation can be derived from MSG images over Belgium regardless of the satellite retrieved GHI accuracy. Moreover, the DNI retrieval from MSG data can be implemented on an operational basis. 相似文献
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通过对唐山市区太阳能和风能资源状况调查分析,对全年不同方位角和倾角上的太阳能辐射量进行模拟计算,得出南偏东9.8°方向、倾角为39.7°的倾斜面上接收的太阳能辐射量最大,其值为1.62×106Wh/m2。研究中对3kW风力发电机和1kW光伏发电系统的发电量进行了计算,并以1辆纯电动轿车为负载进行了容量配比优化,设计了风力发电系统、风光互补系统及光伏系统三种不同的方案,经过对各方案的经济性、可靠性及稳定性分析,得出最佳的设计方案为风光互补发电系统,该系统风力发电装机容量为3kW,光伏发电装机容量为8.96kW。 相似文献