Wednesday, July 30, 2008

Fancy News - Solar Hot Air Collectors in Progress

Today, following the excellent advice and examples on and to also on I indulged my curiosity about solar alternatives for supplemental heating, about specific projects, in especial the active solar hot air collectors - that have use in the Summer as ventilation devices for hot rooms or attics or musty cellars. I like aspects of the three main types of hot air collectors that I see used often and spoken well of, so I decided to make at least one of each (they won't go to waste, immediatly), and gradually:

1) There was progress on a box for the ventilator/heater for the attic window, it will be a black polyester felt absorber type collector, in a "smallish" box of about 45" x 60", this size is to best take advantage of the existing 30" x 30" window opening. and still fit within the eaves and the window frames below it.
The black poly felt came in yesterday as a matter of fact, it is grand, and oh so very warm in it's inimitably polyesterlische way that it gags me to touch.
This black felt absorber theory is interesting. They claim great results from it for heating (but I will be happy just to keep attic from being a late afternoon radiator with any decent ventilation), the idea behind the theory of using felt is that the felt bakes like mad and has a million surfaces to release the heat. It's design is also different than the others in that it lets intake and output share same manifold opening in the unit, albeit with a partition. This attic unit will have a simple flip damper that moves to send heat either out to the sky or back into attic in the Winter (it will be good for the attic to have some heat, it will not be much anyway) - it's main value to me is in it's ability to ventilate the attic/oven in the Summer -

2) There was progress as well on the 4' x 8' box for the flat plate collector - I managed today to make a 1" x 3" frame around a sandwich of a 1/4 inch plywood and a 1" sheet of foiled insulation, with no accidents, gross mis-measuring, or ridiculous patches - this with a power drill, circular saw, and silicone caulk, I have already formed folded sheets of aluminum for "internal girder/baffles" and will assemble them tomorrow or maybe tonight, it is so much fun! Then the alum plate goes over that, cobbled from 36 inch wide sheets, then the cover of polycarbonate roofing, then the tempered glass.

Of course, besides making the collectors, there remains the confusing issue of ducts and fans, with various confusing but clever openings that let air supply be either cool room air or overheated room air, and with exits for heated air to the interior space or to the outside atmosphere - this will call for a dedicated "chimney" on the inside, and a similar one on the immediate outside, for each installation. I would far rather use the systems in the Summer for their excellent ventilation uses than just cover them up. For the big soda can collector I will use a second floor window for air to be delivered to the heater, it will deliver to the collector hot house air in the Summer or cold house air in the Winter, and whenever it sends it's product of hot air back to the inside it will go through an 8" diameter insulated duct of about ten feet long.

I have two huge bags full of Arizona Ice tea cans waiting too, but they need to go to a local friend's house where he has a drill press in his shop for me to trim each one.

Update, I bagged the aluminum beverage can cylinder idea as too much work for similar output, although I will make a soda can collector at some point for the shear joy of it.

See my for other related posts.