Influence of Opaque Photovoltaic Shading on Microclimate and Growth of Strawberry in Greenhouses

Abstract

The effect of photovoltaic PV panels on strawberry growth and the greenhouse microclimate has been studied meanwhile; the annually generated electric energies were estimated by the PolySun program. The peak power of the opaque PV was 310 W. There were four PV panels distributed on the top of greenhouse south plastic roof at a vertical distance of 0.08 m as an isolated air layer under the PV panels at a tilt angle of 30 ͦ . Meanwhile at a horizontal distance between panels of 1.1 m to allow the solar light entering greenhouse. Results revealed that the greenhouse air temperature and solar radiation under the un-shaded greenhouse were higher than that of the shaded greenhouse by opaque PV. Moreover, the opaque PV temperatures ranged from 45 ᵒC to 47.5 ᵒC. The simulation results showed that the annual generated electric energy of the opaque PV panels was 3195 kWh which could cover approximately 30.4% of the annual electric energy demand for environmental control. In addition, there were no significant differences in the number of leaves, flowers including fruits, and chlorophyll contents between strawberries under the shaded and un-shaded greenhouses. In a word, the integration of opaque PV at a specific distribution is highly recommended to provide the required light for photosynthesis and energy for greenhouse without harming the growth of strawberries.

Performance of some spherical eggplant hybrids under plastic house and open field conditions

“…There were no significant differences between the two production systems on leaf chlorophyll reading in both seasons. These results are in agreement with those of Hassanien and Li (2021). Plants produced from plastic house had larger leaf area than those produced from open field; however, the difference was significant in the first season only.…”

“…Similarly, DeGannes et al (2014) and Aied et al (2017) revealed that the high temperature in the greenhouse increases leaf size and leaf expansion. It was reported by Hassanien and Li (2021) that the average leaf area of the shaded strawberry plants by PV was significantly higher than that of the unshaded plants. The eggplant plants increase their height, leaf area and leaf arrangement in order to maximize their exposure to light (Aied et al, 2017).…”

“…It was reported that air relative humidity was raised about 3-6 % inside plastic house than outside by (Farag et al, 2010) Light intensity: Plastic house caused a decrease in light intensity as compared with open field. Results of Hassanien and Li (2021) showed that showed that the light intensity decreased under the polyethylene cover compared with outside the greenhouses. Polyethylene cover reduced the average indoor light intensity by an average of 25.…”

Growth and Physiological Characteristics of Strawberry Plants Cultivated under Greenhouse-Integrated Semi-Transparent Photovoltaics

“…The onset of flowering is not affected by light intensity [ 35 ], which was confirmed in the present study, with the onset of flowering being the same in both crop lines regardless of the shading amount. In previous studies, the shading did not affect the number of flowers for pepper plants [ 37 ] and strawberry plants [ 38 ]. However, in our results, the number of flowers for each crop line was lower compared to the other, after a preceding period of increasing shading.…”