Hrm... Anyone ever built a daytime solar air heat panel?

[skids]

...been looking for some good cheap and cost effective projects that are workable for someone like me who rents a house and can't do major renovations, and I came across this old trick:



These strike me as portable enough to take with me when I leave, and and an easy build/install/removal.

We have some ground floor south facing windows that get decent sun, so I figured I might try these out. Anyone have experience using these? Especially I'm wondering about heat leakage through them at night.

A leightweight, unangled design for suspending them from upper floor windows is here:

http://www.google.com/url?sa=t&ct=res&cd=15&url=http%3A//www.motherearthnews.com/library/1982_November_December/Solar_Rise_Your_Apartment_with_a__75_High_Rise_Heat_Grabber_&ei=aUQCQ8TvK5TKswGbz43kDg

I haven't found anyone that sells them prefab, or so far even in kit form, other than a huckster who is wildly price-gouging. But I haven't been thorough in searching for them either, so maybe someone did get them to market...

[htuttle]

1. I've built those

We used glass-topped plywood boxes insulated with styrofoam and black-painted corrugated steel panels (from salvage) for the collector. I doubt you could build them any cheaper than that. We got about a 20+ degree (F) warming from the air going over the panel once. After about half an hour, there was a definite current of warm air coming out of the top. Not bad, considering how cheap it was to build.

[skids]

2. Cheapest commercial one found so far...

$270 after shipping. For this sort of thing that may still be a bit pricey (surely if they managed to get an economy of scale going these could be produced MUCH cheaper.) Not enough data to decide how long it would take to generate enough heat to offset the 100-150 gallons of heating oil that that represents.

Also it isn't a window-fit unit so it would need ducting. They seem to suggest the intake is not set up for recirculating indoor air, but that could probably be bodged if desired. It is a very light unit that can be roof mounted without much trouble, but does use a small electrical fan rather than vertical heat siphon.

Despite the price it isn't as much of a price gouge as a lot of the other stuff out there, so I figured it's worth passing along:

http://www.metaefficient.com/metaefficient/archives/heating/cleardome-2x4-cleardome-solar-indoor-and-outdoor-forced-air.html