Measured and modeled photovoltaic system energy losses from snow for Colorado and Wisconsin locations
Measured and modeled photovoltaic system energy losses from snow for Colorado and Wisconsin locations
复制标题
对科罗拉多州和威斯康星州地区雪造成的光伏系统能量损失进行测量和建模
DOI：
10.1016/j.solener.2013.07.029
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发表时间：
2013
期刊：
影响因子：
6.7
通讯作者：
G. Sánchez
中科院分区：
文献类型：
--
作者：
B. Marion;R. J. Schaefer;Holden R. Caine;G. Sánchez
一项研究旨在测量科罗拉多州和威斯康星州因降雪造成的光伏系统能量生产损失，并开发一个预测降雪造成的光伏系统性能损失的模型。科罗拉多州和威斯康星州的六个光伏系统的光伏系统性能和相关气象数据在2010-2011年和2011-2012年冬季进行了测量。光伏系统包括两个独立屋顶安装的住宅系统；两个小型商业系统-一个在倾斜屋顶上安装独立安装，另一个安装在平顶上；一个100千瓦机架安装在平顶上；以及一个200千瓦地面安装机架的光伏系统。实测的每月因降雪造成的光伏系统能量损失高达90%。损失占年发电量的百分比从1%到12%不等。开发了一个模型，该模型使用每天的积雪深度来识别新雪的存在；使用每小时阵列平面的辐照度和气温关系来识别何时积雪滑下光伏阵列；使用光伏阵列的倾角来确定积雪滑动的距离；以及光伏阵列上的积雪覆盖的程度来确定光伏阵列的部分能量输出。平均而言，这一模式运行良好。在这两年期间，模拟的年度能源损失不超过非住宅系统测量的0.5%(绝对值)。对于住宅系统，模拟的年能量损失比测量的损失少约1.5%(绝对)。对于每月或更短的时间段，建模的能量损失和测量的能量损失之间应该有更大的差异。模拟的月损失与测量的月损失之间的差异的标准偏差为10.5%(绝对)。
A study was conducted to measure the photovoltaic (PV) system energy production losses caused by the presence of snow for Colorado and Wisconsin locations, and to develop a model for predicting PV system performance losses from snowfall. The PV system performance and associated meteorological data for six PV systems in Colorado and Wisconsin were measured during the winters of 2010–2011 and 2011–2012. The PV systems included two residential systems with stand-off roof mounts; two small commercial systems — one with stand-off mounts on a tilted roof and the other rack-mounted on a flat roof; a 100-kW rack-mounted PV system on a flat roof; and a 200-kW PV system with ground-mounted racks. The measured monthly PV system energy losses caused by snow were as high as 90%. Losses expressed as a percentage of annual energy production ranged from 1% to 12%. A model was developed that uses daily snow depth to identify the presence of new snow; an hourly plane-of-array irradiance and air temperature relationship to identify when snow slides down the PV array; the PV array tilt angle to determine how far the snow slides; and the extent of snow coverage on the PV array to determine the fractional energy output of the PV array. On average, the model worked well. For the two-year period, the modeled annual energy losses were within 0.5% (absolute) of those measured for the non-residential systems. For the residential systems, the modeled annual energy losses were about 1.5% (absolute) less than measured losses. Larger differences between modeled and measured energy losses should be expected for monthly or shorter time periods. The standard deviation of the differences between modeled and measured monthly losses was 10.5% (absolute).