Alrawashdeh, Hatem (2022) A COMPREHENSIVE STUDY OF SOLAR PANELS TILTED UP ON FLAT ROOFS UNDER WIND ACTION. PhD thesis, Concordia University.
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Abstract
The present thesis provides a wind tunnel study dedicated to comprehensively addressing several vital issues in modeling solar panels in atmospheric boundary layer wind tunnels. Atmospheric boundary-layer-wind-tunnel testing has been recognized as a credible tool for generating wind-induced pressures on structures. The simulation process involves duplicating the characteristics of the approaching atmospheric flow and structure modeling. Nevertheless, this process is not straightforward, and various experimental dilemmas always persist. Testing solar panels in simulated atmospheric boundary flow constitutes a case in point where the size of the prototype of the solar panels remains the most significant constraint to the fulfillment of proper modeling.
Recently, there has been considerable growth in the knowledge of wind effects on rooftop solar panel structures, which stemmed chiefly from experimental modeling in the atmospheric wind tunnels, in response to the demands of solar roofing professionals. A portion of the literature work has contributed to the development of the current design provisions of some wind standards and codes of practice. The current practices for wind tunnel modeling of rooftop solar panels are shown to yield significant discrepancies in the results and arise questions concerning the provisions based on such results. Most previous studies have particularly turned a blind eye toward the geometric test scaling requirement to achieve physically testable models in wind tunnels. Other common practices identified in the previous studies, such as incorrectly handling the air clearance underneath the solar array and the pressure taps distribution on the solar panel surfaces, have not received adequate attention during the experimental setup.
The present thesis aims to further expand the knowledge in the area of wind loads on rooftop solar panels with a focus on the aerodynamic and design aspects. The objectives of this research are to thoroughly quantify the distortions of the experimental results due to the experimental practices of modeling solar panels tilted on flat roofs in atmospheric wind tunnels, considering that (1) enlarging the geometric scale of the test models; (2) modeling the air clearance between the solar array and the building roof; and (3) arranging the pressure taps coverage on the test models pose modeling challenges shown to be crucial for producing credible wind-induced surface and net pressures on solar panels. The intended objectives of this thesis have been accomplished through a series of wind tunnel experiments carried out in the boundary layer wind tunnel of Concordia University. Three wind tunnel models were designed at geometric scales of 1:200, 1:100, and 1:50 for a prototype of a solar array of eight typical panels mounted on a building with full-scale plane dimensions of 14.0 m and 27.0 m and a height of 7.5 m. The designed models were tested in standard open-country exposure commonly used for codification studies. The solar array of the larger model was placed at three clearance heights above the roof, including gaps of 0, 20 cm, and 40 cm (in full-scale equivalent). Furthermore, six different configurations of pressure-tap coverage were investigated.
The assessment of the results demonstrates that these experimental considerations are critical for modeling rooftop solar panels in the atmospheric wind tunnel. It was found that the surface and net pressures of the solar panels are very dependent on these considerations with high spatial heterogeneity within the array. The thesis has stressed that caution needs to be exercised when testing solar panels in atmospheric wind tunnels and that improper implementation of these requirements could dramatically risk the credibility of the experimental outcomes and conclusions, notably those treated as design loadings. Finally, a procedure for modeling rooftop solar panels utilizing enlarged models in open-terrain exposure is formulated to assist the generation and codification of design wind pressure coefficients. Furthermore, recommendations are made to remedy the potential distortions owing to the shortfalls in the current design provisions. All proposals are crafted in the interests of practicing wind engineers and architects, code officials, and codification committees.
| Divisions: | Concordia University > Gina Cody School of Engineering and Computer Science > Building, Civil and Environmental Engineering |
|---|---|
| Item Type: | Thesis (PhD) |
| Authors: | Alrawashdeh, Hatem |
| Institution: | Concordia University |
| Degree Name: | Ph. D. |
| Program: | Building Engineering |
| Date: | 24 October 2022 |
| Thesis Supervisor(s): | Stathopoulos, Theodore |
| Keywords: | Wind Tunnel, Modeling, Design, Wind pressures, Wind loads, Solar panels, Codification, Air Clearance, Pressure distribution. |
| ID Code: | 991356 |
| Deposited By: | HATEM ALRAWASHDEH |
| Deposited On: | 21 Jun 2023 14:26 |
| Last Modified: | 21 Jun 2023 14:26 |
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