Feasibility study of a blind-type photovoltaic roof-shade system designed for simultaneous production of crops and electricity in a greenhouse
Feasibility study of a blind-type photovoltaic roof-shade system designed for simultaneous production of crops and electricity in a greenhouse
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DOI：
10.1016/j.apenergy.2020.115853
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发表时间：
2020-12-01
期刊：
影响因子：
11.2
通讯作者：
Yoshioka, Hidekazu
中科院分区：
文献类型：
--
作者：
Li, Zhi;Yano, Akira;Yoshioka, Hidekazu
在现代温室管理中使用可再生能源对于为人口不断增长的世界实现高效和可持续的粮食供应至关重要。本研究评估了一种盲式遮阳调节器的性能，该调节器可以自动旋转安装在温室屋顶上的半透明光伏（PV）叶片，以响应阳光的变化。平行于屋顶的光伏百叶窗部分阻挡了强烈的阳光穿透到温室中，但它通过将百叶窗轴承旋转到垂直于屋顶来在多云时间传输阳光。因此，在变化的天空条件下，可在温室中产生稳定的照射环境。全年运行情况表明，百叶窗自身产生的电能可以维持光伏百叶窗运行，并产生剩余电能。利用理论太阳光参数和实验获得的光伏百叶系统参数建立数学模型，计算光伏百叶发电量和光伏百叶屋顶下作物的太阳光利用率。假设天空无云，盲转的阈值辐照度设置为500 W m（-2），13.0和12.3 kWh m（-2）yr（-1），则南北和东西方向的模型温室可以分别产生剩余电能。多云的天空会减少50%的剩余电能生产，但光伏百叶窗可以部分或全部满足温室的电能需求，具体取决于温室的电气化程度。在PV百叶窗下方，在实际天空条件下，预计8-10 MJ m（-2）天（-1）的日射量将照射作物。这样的日照量足以种植主要的园艺作物。调节光伏盲转的阈值辐照度水平可以控制用于栽培和发电的太阳光分配比例，从而实现温室中可持续的能源-粮食双生产。
The use of renewable energy in modern greenhouse management is important to achieve efficient and sustainable food supplies for a world with increasing population. This study assessed the performance of a blind-type shading regulator that can automatically rotate semi-transparent photovoltaic (PV) blades installed on the greenhouse roof in response to sunlight variation. The PV blind oriented parallel to the roof partially blocked intense sunlight penetration into the greenhouse, but it transmitted sunlight during cloudy time by turning the blind bearing to be perpendicular to the roof. A stable irradiation environment is therefore producible in the greenhouse under variable sky conditions. Annual operations demonstrated that the blinds' own generated electrical energy can sustain PV blind operation and produce surplus electrical energy. The PV blind electricity generation and sunlight availability for crops below the PV blind roof were calculated based on a mathematical model developed using theoretical sunlight parameters and the experimentally obtained PV blind system parameters. Assuming cloudless skies and threshold irradiance for blind rotation set at 500 W m(-2), 13.0 and 12.3 kWh m(-2) yr(-1) surplus electrical energy can be generated, respectively, by north-south and east-west oriented model greenhouses. Cloudy skies reduce surplus electrical energy production by 50%, but PV blinds can supply greenhouse electrical energy demands partially or completely, depending on the degree of greenhouse electrification. Below the PV blinds, 8-10 MJ m(-2) day(-1) of insolation is expected to irradiate crops under actual sky conditions. This insolation is sufficient to cultivate major horticultural crops. Regulating the threshold irradiance level for PV blind turning can control the sunlight apportionment ratio for cultivation and electricity generation, thereby enabling sustainable energy-food dual production in a greenhouse.