Hybrid Car – More Fun with Less Gas

Re: Solar water heating system value - Page 4

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Posted by nicksanspam on March 10, 2006, 2:40 pm

Or put a T 6' above the tank with a small tube that goes back to the tank.


Posted by Doctor Drivel on March 10, 2006, 3:02 pm

6 foot?  This pipe will take water back to the tank, and may disturb
stratification.  You could have it horizontal above the tank water line and
it sprays onto the surface not disturbing stratification. Best have the pipe
small bore like 6mm to 8mm.

As hot water comes in from the panels you want this to stay at the top of
the tank. You don't want to disturb any stratification aiming to reinforce
it putting hot water at the top.  Pumping it into the centre of the water
body will make it warm with mixing. Not what you want.

Best have a tee under the lowest water level that acts as a spreader. Pipe
in ->  tee -> two lengths of pipe horizontal from each port of the tee to
the edges of the tank -> cap on each end.  Drill holes in speader pipe
horizontally, so hot water does not flow downwards into the main water body
and stays on the surface.

Now for the vent.  Just before the speader tee insert another tee, this can
be under the water line. Take a soft copper pipe, about 8mm, from the tee up
and out of the water to the highest level in the tank, Bend it downwards in
a "U".  Depending on pump pressure and size of holes in the spreader pipes,
water should take the line of least restisance and not work its way up the
soft copper pipe, only exiting via the speader pipes.

Posted by meow2222 on March 10, 2006, 5:15 pm
 Doctor Drivel wrote:

What I'm suggesting is a 1/4" hole in the panel output pipe just above
the top of tank, say 1/2" above. There will be close to no pressure
there, and no possibility of any squirting.


Posted by daestrom on March 10, 2006, 9:39 pm

Okay, and if there is no check-valve in the pump or its suction, I can see
that working.  Maybe even a baffle just to be sure of little splash.
Shut-off head of the pump will still have to be high enough to initially
fill the collector, but once the return has flooded, less pressure should be
needed to maintain flow.

Now, just need a large enough tank to accomodate the drain-water, and you're
all set.


Posted by Doctor Drivel on March 10, 2006, 10:06 pm

Although it would take three pipes.  A foolproof way is have a tee inside
the tank on the hot pipe from the panels. From this tee take a small bore
pipe up to the same height as the top of the panel and back to the tank.
Vented and no pump over at all.  If there is a problem it goes back to the
tank.  Pipe is cheap.

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