Hybrid Car – More Fun with Less Gas

Is Efficiency dangerous ? - Page 15

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Posted by Greg Campbell on November 5, 2005, 2:26 am
 
Christian Kaiser wrote:


"Reservoir Tank

The drainback reservoir tank holds the collector fluid. It
can be installed at any height above the solar storage
tank, but must be within a conditioned or freeze-free
environment. The reservoir tank is typically mounted on
a strong shelf above the storage tank. It may also be
placed on the second floor of a two-story home to
reduce static head by decreasing the distance the pump
must lift the fluid to the collector."

So much for my 'claim' of originality.  :)

-Greg

Posted by Greg Campbell on November 5, 2005, 2:20 am
 
Iain McClatchie wrote:


Depends. ;)

It need to have sufficient capacity to accomodate the water in the
panels, when they drain, and to allow for the thermal expansion you
mention.

<Sound of rusty grinding gears....>

It would be simple to add a float switch to the E.R. If the water level
falls too low, a small auxiliary pump/tank adds water to the system.  At
the other extreme, a simple overflow drain, leading back to that aux
tank, would catch any thermaly induced spillover.  Compensating for the
thermal issues should allow a much smaller E.R.  (The few dozen feet of
plumbing in and around the panels can't hold too much.)


OK, if you say so.  :)

I hadn't done any math along those lines.  I was simply looking for a
way to reduce pumping effort, while still allowing a full draining of
the panels.  The system I'm contemplating is for my mom's mobile home,
and will be rather small.  Thermal expansion was barely on my radar.

I'm a bit surprised that it seems to be an 'original' idea.  I've not
yet seen a similar idea described on line.  And here I went and blabbed
it to the internet.... There goes 'another' (LOL) opportunity to make
millions!  :)

-Greg



Posted by Solar Flare on November 5, 2005, 1:00 pm
 LOL. It appears to be a well established method, published in many, many
websites but many have gotten into this and confused the issue badly.

Now we are talking about adding water to a closed system. I wonder when it will
burst?...LOL

In the supplied link system the pump has to ***not*** have a checkvalve so that
the drainback is accomplished back through the pump to the E.R. tank. The whole
thing is quite genius but not the previous way I was shown elsewhere with the
air intake valve etc..



Posted by nicksanspam on November 4, 2005, 9:24 am
 

So... if the main tank is say, 16' below the ER, it is slightly pressurized
by about 0.433x16 = 7 psi, ie 1000 psf, so the top of a 4'x8' main tank
would need to resist 16 tons of uplifting force? :-)

The main tank might have a big coil of PE pipe on the bottom, with no ER...

Nick


Posted by Iain McClatchie on November 4, 2005, 9:44 pm
 NIck> So... if the main tank is say, 16' below the ER, it is slightly
pressurized
Nick> by about 0.433x16 = 7 psi, ie 1000 psf, so the top of a 4'x8'
main tank
Nick> would need to resist 16 tons of uplifting force? :-)

Ouch.  If the dirt/rock over the main tank is density==2 kg/litre, then
half
the height to the aux tank has to be filled in.


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