The Complete Guide For Solar Panel Design Systems - Part 1

Design I — Modular

The initial design is simple yet robust, and is composed of only two elements, a foot and slat. As shown in Figure 1, the panels are mounted to slats that are joined by feet. The grooves in the foot component shown in Figure 2 constrain the slats from rotation. A single stainless steel bolt constrains the slat in the vertical as well as lateral axes.

As with traditional mounting systems, the panels are glued to the slats. The installation costs are greatly reduced because there is no on-site

customization for oddly shaped roofs; that is, the panels can be arranged in several configurations to adapt to roof obstructions. When mass-produced, the foot and slat components cost less then $3 each, and the total cost per panel is about $18.

For smaller-scale production runs, a wood/plastic composite lumber could be used as an alternate material to injected molded plastic. This composite material is corrosive-resistant and can be cut and drilled similarly to wood.

This design meets all of the functionality requirements named previously, except for the 90 mph wind rating of Massachusetts building codes, which has yet to be proven.

Due to the complications in theoretically modeling the system, an experimental model has to be made of air flowing over the top of commercial buildings, and the lift and drag forces on the system must be measured.

Because the weight of the panels is not sufficient for keeping the system stationary, the corners of the array have to be constrained by cable stays that can be mounted to the side walls of the roof.

The aims of this experimental test are to determine the necessary constraining forces as well as to find any system complications such as resonance frequencies that may arise in storm conditions.

Once the forces are calculated, finite element analysis software can be used to specify the contact stresses in the glass panels. The high wind-speed conditions on the roof of a commercial building will be simulated at the MIT water tunnel. The schematic

The tunnel is 1.2 meters long and has a cross section of 0.5m x 0.5m. The water flows over the bulkhead to simulate the walls around the roof of a commercial building.

The one-third-scale panel in the experiment is a stainless steel plate of dimensions 0.64m x 0.32m x 0.008m. As the water flows over the bulkhead, water can flow above and below the panel because there is a clearance of 0.01m to simulate ventilation under a panel.

To vary the position of the panel, the distance between the panel and bulkhead can be adjusted up to 0.64 meters.

Design II — Corners

For every design there are revisions for different applications. In this case, the customer has dictated the creation of the three subsequent designs. MIT facilities recently received a grant to install solar panels on campus.2

The supplier of solar panels uses various panel sizes that are not compatible

with the Modular design.

It would therefore be necessary to have shorter or longer slats depending on the specific size of the panel as there is not one industry standard.

This issue spurred the idea of having a configuration that is not constrained by the specific dimensions of the panel. Removing the slats and modifying the foot component developed a design whereby the panel is only constrained in the corners.

The corners of the panel are sandwiched in between two symmetric parts.

To reduce possible concentrated stresses on the extremely inelastic glass panels, a thin layer of neoprene can be inserted between the plastic and glass. The installation efforts are also reduced with this design because the gluing phase is eliminated. The drawback is that a small portion of the photovoltaic cells are blocked off from sunlight.

In addition, the system is not as robust as the first: The slat backing does not fully support the panels. Under high winds, vibrations may dangerously strain the panels, reducing the life of the photovoltaic cells.