Solar Water Panel Design
Engineers required: What stress would a glass roof panel be subjected to?
I'm redesigning a enclosed courtyard area within a building. My idea involves using glass roofing with thermally insulated louvres to shut at night to increase thermal efficiency yet allow natural daylight during the day and still minimise solar gain. The design would also be horizontal, to a degree, perhaps a slight gradient for water drainage.
My question is, what stresses should i consider when thinking of creating a roof area of approx 10m x 25m? How could i support this glass roofing system? Are automated louvres systems heavy (cost would also be helpful)? What is the dimensional stability of sheet glass in roofing? how many square metres of glass can be used as roofing without needing cross beams?
Apologies for all of the questions, but that's what you get being an engineering student. Any help is greatly appreciated, as is any other suggested materials to satisfy the building requirements.
Your first reference should be the local building code. In the US, that would be the International Building Code, 2000, 2003, or 2006. All have a chapter on glazing and glazing systems, which is what you're trying to do.
As far as spans or stresses, there are material standards you can look up for that, although the organizations that make them I don't know - perhaps American Glazing Institute, or an architect might know.
The louvre system is probably a) a specified item, and doesn't exactly sit on the glass but rather would have its own support system to span a few feet. If you need a starting point, I'd start with a 2'-0" x 2'-0" grid of aluminum channels, perhaps 3/8" thick glass just to start things out on sizing. This is really a subsystem, you'll need a more structural system to support the aluminum grid. (Think of plywood on wood joists on beams - the plywood is glass here, the joists are the aluminum channels, and the beams are... beams).
The dimensional stability of the glass probably won't be too much trouble as you're going to order large sheets of glass that are cut to size. They will be small enough that the aluminum channels will accommodate the thermal expansion and contraction of the glass, you'll need a sealant like caulk that will accommodate that movement.
I don't think a practical thickness of glass will span a meter.
I don't really understand your logic - you want louvers to close and increase thermal efficiency, but you want to minimize solar gain. The two don't make much sense together. I would think you'd want to maximize solar gain during the day and hold the heat with the louvers closed.
You should also investigate snow load and wind load. A slope of 1/8" per foot is typical code requirement although the code for skylights may be different. I'm pretty sure Chapter 24 of the IBC has material on skylights and references other standards. Start there.