I'm going to slap this together over the weekend and see if it will give off any heat. Any opinions about this? Think it will work?

http://imageshack.us/photo/my-images/856/solar01.gif/

http://imageshack.us/f/856/solar01.gif/



Guv Bob

On 15/01/2013 3:08 PM, Guv Bob wrote:
I'm going to slap this together over the weekend and see if it will give off any heat. Any opinions about this? Think it will work?

http://imageshack.us/photo/my-images/856/solar01.gif/

http://imageshack.us/f/856/solar01.gif/



Guv Bob



A shield to prevent wind losses would probably be essential. Perhaps a
small solar fan to push the air along.

Rather than a reflective system, what about using a 50m roll of 1/2"
poly reticulation pipe as the collector. Very cheap & larger collection
area (though not focused energy gathering).

"Guv Bob" wrote in message
m...
I'm going to slap this together over the weekend and see if it will
give off any heat. Any opinions about this? Think it will work?

http://imageshack.us/photo/my-images/856/solar01.gif/

http://imageshack.us/f/856/solar01.gif/



Guv Bob


Not a lot of quantitative engineering specs there to make a judgment, and I
am not really an expert, but here are some observations:

If you want warm air to enter the house you have to remove (hopefully
colder) air through another opening or let it escape. Hot air heating
systems circulate air within the house.
The type of reflector you illustrate has to be tilted throughout the day,
but it will probably be ok for a couple of hours around midday with no
movement depending on the diameter of the pipe and design of reflector.
A hot air system requires large diameters to transfer heat efficiently. A
small pipe will not allow much heat transfer with air especially just
relying on convection. If you use large aluminum air ducts, that might be
OK as long as the input is fed from a cool part of the interior, not the
exterior. Of course then your reflector has to be very large.

Water has much better heat capacity, and convection of water in a pipe can
transfer much more heat than convection of air in the same size pipe. I
would fill the pipe with water, have it convect to a radiator inside, and
then the return will go back to the low end of the reflector. Also, make
the reflector a CPC design (compound parabolic concentrator, see for
example: http://www.fossilfreedom.com/increase-output.html ) so it does not
have to be tilted throughout the day.

On 1/15/2013 1:04 AM, anorton wrote:

snip
reflector. Also, make the reflector a CPC design (compound parabolic
concentrator, see for example:
http://www.fossilfreedom.com/increase-output.html ) so it does not have
to be tilted throughout the day.

This is interesting. Anybody built one and evaluated it?
While it looks rational, I wonder about stuff that's been around
for decades, looks vastly superior, but is not in general use.
How come it's not standard construction?

My understanding, is that there is not a lot of power
with solar. Watts per yard, or BTU per square yard,
or whatever the measurement. Not a lot of power.
Some design factor or other, will make or break the
output.

You'd by very wise to do some internet research,
and see if you can find actual plans of a collector
someone else built. Others have gone through the
test stages, and done the leg work for you.

Christopher A. Young
Learn more about Jesus
www.lds.org
..

"Guv Bob" wrote in message
m...
I'm going to slap this together over the weekend and see if it will
give off any heat. Any opinions about this? Think it will work?

http://imageshack.us/photo/my-images/856/solar01.gif/

http://imageshack.us/f/856/solar01.gif/



Guv Bob

there is a ton of info out there on "passive solar heaters" (not water) -- I'm doing one this spring out of sliding patio door I took out. you build a frame, room air goes in the bottom and hits a series of baffles (black inside) and outlets at the top (with small thermostatically controlled fan -- heat rises). if you have good southern exposure and design it well, these put out a LOT of heat.

i just thought of using my patio door last week -- no need to scrap it now.

"mike" wrote in message
...
On 1/15/2013 1:04 AM, anorton wrote:

snip
reflector. Also, make the reflector a CPC design (compound parabolic
concentrator, see for example:
http://www.fossilfreedom.com/increase-output.html ) so it does not have
to be tilted throughout the day.

This is interesting. Anybody built one and evaluated it?
While it looks rational, I wonder about stuff that's been around
for decades, looks vastly superior, but is not in general use.
How come it's not standard construction?

Actually the CPC design is becomming very common in solar concentrators for
hot water. You can see see lots of collectors like this for sale on the web.

Like any other engineering choice, there are trade-offs. A simle parabolic
cross-section reflector is a little cheaper and can also concentrate the
light onto a smaller tube yielding higher tempertures and better efficiency
on clear days. However, it needs a tracking motor and mount to follow the
sun. In a large solar farm with long banks of reflectors, the cost of the
motor and maintenance of moving parts is probably more than offset by better
efficiency from higher temps and the lower cost reflector itself. In a
smaller installation, it is probably the other way around. Also, the CPC
design is more efficient at concentrating energy on hazy or slightly cloudy
days, so it might be the better choice if you are not in the dessert.

The other choice is a flat panel collector, or array of tubes, but that
yields lower temperature water. This is still the most common for a small
installation.

"Guv Bob" wrote in message
m...
I'm going to slap this together over the weekend and see if it will give off
any heat. Any opinions about this? Think it will work?

http://imageshack.us/photo/my-images/856/solar01.gif/
http://imageshack.us/f/856/solar01.gif/
Guv Bob

I might work, but very poorly. The small pipe will have significant resistance to
air flow and a concentrating collector will reradiate much of the heat out of the
collector.
Google "solar flat plate air collector".
Art

On Mon, 14 Jan 2013 23:08:03 -0800, "Guv Bob"
wrote:

I'm going to slap this together over the weekend and see if it will give off any heat. Any opinions about this? Think it will work?

http://imageshack.us/photo/my-images/856/solar01.gif/

http://imageshack.us/f/856/solar01.gif/



Guv Bob
You'll get SOME heat.

wrote in message ...
On Mon, 14 Jan 2013 23:08:03 -0800, "Guv Bob"
wrote:

I'm going to slap this together over the weekend and see if it will give off any heat. Any opinions about this? Think it will work?

http://imageshack.us/photo/my-images/856/solar01.gif/

http://imageshack.us/f/856/solar01.gif/



Guv Bob
You'll get SOME heat.

Hey, I already get plenty of heat from the knuckleheads at work!! LOL! The only way to find out is to put something together so I'll give it a try this weekend.