Agrivoltaic system: Estimation of photosynthetic photon flux density under solar panels based on solar irradiation data using all-climate solar spectrum model
Agrivoltaic system: Estimation of photosynthetic photon flux density under solar panels based on solar irradiation data using all-climate solar spectrum model
复制标题
农业光伏系统：利用全气候太阳光谱模型，根据太阳辐照数据估算太阳能电池板下的光合光子通量密度
DOI：
10.1016/j.clet.2022.100594
复制
发表时间：
2023
影响因子：
--
通讯作者：
Nishioka Kensuke
中科院分区：
文献类型：
--
作者：
Yajima Daisuke;Toyoda Teruya;Kirimura Masaaki;Araki Kenji;Ota Yasuyuki;Nishioka Kensuke
气候变化和人口增长导致的粮食产量增加是需要立即关注的全球挑战。引入可再生能源来缓解气候变化和需要充足的土地来增加粮食产量通常是相互排斥的。然而，农业光伏系统产生可再生电力，并在一块公共土地上生产农产品，从而提高了土地生产力。此外，该系统有助于当地生产，从而减少物流中的二氧化碳排放。以前的研究中的光伏阵列是通过计算辐照度（W/m2）来设计的，即使在最近的研究中也是如此。为了实现高效农业，必须对农田照明进行仔细设计。模拟必须基于光合光子通量密度而不是光伏技术模拟中常用的辐照度进行缩放。本研究重点关注光合光子通量密度，并采用全气候太阳光谱模型来准确计算被太阳能电池板和支撑管部分遮挡的农田上的光合光子通量密度。这项研究描述了一种估计太阳能电池板下光合光子通量密度值的算法。使用光合光子通量密度传感器验证计算的数据。为了计算太阳能电池板下的光合光子通量密度，必须分别权衡太阳能电池板遮蔽的直接和漫射分量，因为它们具有不同的光谱。这里探索了一种量化阴影的方法，通过太阳能电池板及其支撑管来测量太阳移动时的直接和漫射分量。通过定义太阳的移动以及太阳能电池板及其支撑管相对于观测点的仰角和方位角的位置来建立计算公式。结果发现，基于太阳能电池板下光合光子通量密度计算公式的波形再现了与测量的光合光子通量密度相同的趋势。为了从数字上评估这种趋势，使用标准残差对测量的和计算的光合光子通量密度进行了比较。一般来说，两个值的相似性是通过-3和3之间的标准残差值来证实的。本研究结果表明，除了夜间光合光子通量密度为零之外，更多频率的标准残差值为负。这表明计算的光合光子通量密度往往高于测量的光合光子通量密度。标准残差的峰值频率在-6和-3之间。出现这种差异的原因可能是，所建立的计算公式针对的是太阳能电池板和支撑管提供的遮阳，但没有涵盖其他系统结构提供的遮阳。该计算公式使农民能够在引入系统之前利用目标农田测量的太阳辐射数据来评估该系统的经济效益，通过引入公布的邻近太阳辐射数据并提前考虑避免遮挡对农业生产影响的措施。下一步的研究将是通过增加天数来提高计算公式的准确性，并通过引入该系统开发一种导致农业生产和太阳能发电最佳实践的方法。
Climate change and increasing food production due to population growth are global challenges that need immediate attention. The introduction of renewable energy to mitigate climate change and the requirement of adequate land to increase food production are generally mutually exclusive. However, an agrivoltaic system generates renewable electricity and produces agricultural products from a common piece of land, thus increasing the land productivity. In addition, this system contributes to local production, thus reducing the CO2emissions from logistics. Photovoltaic arrays in previous studies were designed by calculating the irradiance in W/m2, even in recent studies. A careful design of the farmland's illumination must be developed for effective agriculture. The simulations must be scaled based on photosynthetic photon flux density rather than irradiance commonly applied in photovoltaic technology simulations.This study focused on the photosynthetic photon flux density and employed an all-climate solar spectrum model to calculate the photosynthetic photon flux density accurately on farmland partially shaded by solar panels and supporting tubes. This study described an algorithm for estimating the photosynthetic photon flux density values under solar panels. The calculated data were validated using the photosynthetic photon flux density sensors. To calculate the photosynthetic photon flux density under the solar panels, it is essential to weigh the direct and diffused components shaded by the solar panels separately because they have different spectrums. A method to quantify the shading was explored here by solar panels and their supporting tubes for the direct and diffused component as the sun moves. The calculation formula was established by defining the sun's moves and the positions of solar panels and their supporting tubes in terms of elevation and azimuth angles from the observation point.It was found that the waveform based on the calculation formula for the photosynthetic photon flux density under the solar panels reproduced the same tendency as the measured photosynthetic photon flux density. To evaluate this trend numerically, the measured and calculated photosynthetic photon flux densities were compared using the standard residuals. Generally, the similarity of the two values is confirmed by a standard residual value between −3 and 3. The result of this study showed that the standard residual values were negative in more frequencies except for the zero photosynthetic photon flux density at night. This indicates that the calculated photosynthetic photon flux density tends to be higher than the measured photosynthetic photon flux density. The peak frequency of the standard residuals was between −6 and −3. This difference probably occurred because the established calculation formula targets the shading provided by the solar panels and supporting tubes but does not cover the shading provided by the other system structures. The calculation formula enables farmers to evaluate the economic efficiency of the system before introducing it using measured solar irradiation data at the target farmlands by introducing published neighborhood solar irradiation data and considering, in advance, measures to avoid the effects of shading on agricultural production. The next study will be to improve the accuracy of the calculation formula by increasing the number of days and develop a method that leads to the best practices of agricultural production and solar power generation by introducing the system.