Registered: 1518026946 Posts: 3
Reply with quote #1
I need to get a volume of a few cubic feet (typically 4.5CF) heated to above 97F and close to 104F (36-40C) for few minutes a day and to above 104 and less than 113F (40-45C) with input temperatures below 117F for 150 minutes several times a season. A slanted ZP screen collector would avoid the Czech produced internationally patented passive flat plate design and closely meets temperature goals. I’d like to use a solar powered Arduino to control PWM fans and dampers on very small ducting (~2”). I have some issues:
1. Finding small duct damper that can be controlled with low power. 5V computer 40x40mm fans are about the right size and are fairly low power. I’m looking for a supplier of small ducting and dampers.
2. Rather than use twin wall, I’m thinking of using polycarbonate (or if I can find security glazing, glass) panes with SuperSpacer or Duralite. Has anyone done that?
Registered: 1388591029 Posts: 2,731
Reply with quote #2
Dampers that size could be hard to come by. A couple suggestions:
1. Make your own and operate it with a hobby servo, which the arduino can easily control.
2. Skip the powered damper and use a simple plastic or cloth flap, operated by fan pressure.
3. For ducting you might consider 2" pvc drain pipe.
4. We use twinwall because it's "relatively" cheap, light, unbreakable and has some insulating value. Glass works fine and has better transmissivity. Some have even used plastic film.
5. A "12v" PV panel has an open-circuit voltage of nearly 22v; you'll need some kind of regulator.
6. You'll need to provide a means of venting your collector when the heat is not needed, though you can design this into your ducting. The Arduino can control it for you. __________________ Solar is like the wind. It may be free, but putting it to work isn't! Willie, Tampa Bay