flat plate evacuated solar panel

I am trying to figure how to make an evacuated flat plate solar thermal panel
( sort of this one: www.genersys-solar.com/downloads.asp ).
Main problem so far is how to keep air out (vacuum) .
What sort of o-ring should I use ?
Would it be possible to use Arduino to control internal vacuum and act a vacuum pump to keep it balanced in time ?

sort by: active | newest | oldest
lemonie8 years ago
You pump it out and leave it like that. Adding a pump to the system would detract from energy savings and add to cost.
How far have you got with it?

gabdab (author)  lemonie8 years ago
yet have to start collecting items.
Adding a cheap converted pump for vacuum wouldn't add much, you can find little air compressors on ebay for like 10 $.
This is an how-to for converting to vacuum:
As for microcontroller I plan to use an Arduino board (~30 $) which I would eventually use for solar tracking also.
Couple of thermal sensors and valves and the vacuum job is done ..
Problem is how to achieve a reliable vacuum in a 'metal box - glass panel' thing so not to over-depend on the vac pump ( energy consumption).
lemonie gabdab8 years ago
You don't want to have a controlled-pump on this: evacuate it and leave it sealed. Silicone sealant will probably do you if used correctly.

gabdab (author)  lemonie8 years ago
I guess so, as a matter of fact silicone sealant is used on aquariums also.

Aquarium's water pressure = flat panel's vacuum pressure ?
If this is the same it might work..

lemonie gabdab8 years ago
Negative pressure exerts a different type of force, but provided you have the panel sealed correctly I'm sure the sealant would hold a vacuum. Thin layer between glass and box, maybe 0.5 inch width, bead around the outside edge to be sure.

gabdab (author)  lemonie8 years ago
I guess 0.5 inch would work for the gasket bed and if I bead around the outside edge I could use one (gasket) on the bottom and one on the side of the glass to be sure that air won't get in ..

I have seen something online about how to make metal boxes , but never tried before.
I wish there was a way to metal forming with a metal press on a shoe string budget so to be able to achieve a no solder box, but I guess I will stick with folding a metal sheet .