A Structural and Environmental Assessment of Pavement Solar Panels
The concurrent energy shortages of non-renewable energy resources have directed attention to the potential of harvesting renewable energy resources from roadway. Strong incentives to sustainable solution to this problem have led to the design of innovative pavement solar panel technology. This research is based on designing and developing a solar panel for roadway application. The designed prototype consists of a thin film solar panel, a transparent cover to protect the solar panel and a wooden frame to support the whole configuration. Since the pavement is exposed to solar radiation throughout the daytime, the pavement embedded solar panel will be utilized to harvest the solar energy and store with the integration of storage system and convert into electricity. It should also provide service during power failures in remote areas without electrical utilities. The main challenge of the project is the selection of proper transparent cover since it should bear the traffic loads and should not impair the transparency at the same time. The types of transparent covers chosen for this study are polycarbonate samples of varying thicknesses, textured glass grit sample and textured float glass with corundum skid resistant coating on the surface. Percentage transmittance of each samples was determined using transmittance spectroscopy in the visible light range. The percentage transmittance for the 10 mm, 12 mm and 16 mm polycarbonate samples were 87%, 84% and 82% and for textured glass grit sample it was 40% at each wavelength in the visible light range. The finite element analysis was carried out to replicate the in-situ installation of the solar panels with polycarbonate shield covers to determine the structural feasibility. The prototype panel was subjected to static and dynamic loading and the stress, strain and deflection analysis was performed and compared with a typical pavement model without any transparent cover. Finite element analysis demonstrated that the panel would not fail by fatigue under the loading condition considered. Power generation data from these solar panels were collected and compared in a wide range of weather conditions and different seasons to assess the relationship of power and other environmental factors such as irradiance, illuminance, temperature, and cloud cover Since the panels were designed for pavement application, the panels were subjected to vehicular loading during the field tests to determine the decline in the power output due to shading of vehicles. Another purpose of the field test is to analyze whether the transparent covers face any disruption, damage, or failure under the wheel loading. Although polycarbonate samples and textured float glass sample can withstand traffic loads, the textured glass grit sample failed in fracture without any warning of failure under wheel loading. Experimental results also showed that 12 inch × 12 inch pavement solar panels generate an average of 2.2 W in sunny condition but produce less power in cloudy condition. Based on the power production data of SP10 from 12 PM to 6 PM, its feasibility was assessed for utilizing in the smart pedestrian system to lighten the crosswalk and alert the drivers of approaching vehicles.