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stmbtwle

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Reply with quote  #51 
If you want it to work right, yes. You can get a thermosiphon with the tank below the collector, but it works backwards. NOT what you want.
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Willie, Tampa Bay

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Reply with quote  #52 
Yes, those are good points.

However, after more thinking on this, since I posted, [rolleyes] I have been thinking that a "straight siphon" between barrels ought to work: "hot" barrel empty of water, COLD barrel full...

then force water up the pipe towards the collector, using street pressure off of a hosepipe...

When water runs out of air side, dip the wet side (held by a brick...)

The siphon should maintain itself (one barrel empties, one barrel fills...

then as the collector warms up, the water should also...

Apologies for the wrong term: it is not a THERMO siphon, but a GRAVITY FEED, conveying waters of differing temperatures...

Then it ought to fill up the HOT barrel with HOT water (eventually)

Like Willie says, there is only one way to verify this...

Guess this shows one thing at least, namely, the utility of posting to the site !

Thanks for the feedback once again, fellows !

G_H

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(1)  "Heat goes from hot to cold, there is no directional bias"
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mattie

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Reply with quote  #53 
A check valve or NRV would be useful in preventing back flow of hot water to the drain back tank.
Regards Mattie
stmbtwle

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Reply with quote  #54 
I think a check valve would defeat the purpose of a drain back system. You WANT the water to drain into the tank, so it doesn't sit in the collector and freeze.

I like the idea of the multi barrel system though I don't know how well it works. There are some articles on BIS, I think.

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Willie, Tampa Bay
Garage_Hermit

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Reply with quote  #55 
Thanks, Mattie, I ended up finding one !
 

[clapet-anti-retour-pvc-77396-2561023]



Willie, I think what Mattie was talking about, was putting one of these on my proposed *PVC-SIPHON* system (used with your excellent "Folded Riser" design)...

Because with the siphon system, the drainback would take place into the COLD tank, by breaking the siphon (= lifting the brick out of the tank...).
(although, thinking about it, there is no risk in any case of HW flowing back up to the collector, because the end of the HOT delivery pipe is in AIR (it delivers into a colander, fited in the top of the tank, to maintain stratification...).

(guess This is my fault, for mixing two designs...).
============
Regarding TANKS, Yeah, I like the sound of multidrum storage also !  the reason is, getting *any* storage into my crawlspace is off to be a tough one !   The access door is only about 80 cms tall by 70 cms wide...

So I am intending using THESE... 240-liter Yellow Wheelie Bin
[image]
Initially, I would use one YWB to receive the incoming hot water, and it would overflow/feed into 3 x 80-liter black tubs, representing the return side of the system.

So my next design element, is defining the STANDPIPE systems required to transfer the water inter-tanks...

=======

Cannot tell you how much I am struggling here, to keep my feet on the pedals, I feel like the project is starting to take off ! (thanks to all latest feedback !)

In addition, I have to fight with Analysis Paralysis, since I must admit to STILL having images of Curly Red Pex, laid in serpentines inside Black-painted Steel Trays...

HOWEVER [rolleyes] what is keeping me focussed is, we have had a 10-day DARK SPELL - cold and rainy - I even had to resort to putting my infloor electric slabs ON... [redface]  so this is encouraging me to pursue this Slate Facade Development !

AND (following from recent post of just today...) I reckon I am abandoning the idea of pulling outside air in thru slates... Instead, I will add EXTRA HYDRAULICS into those 3 air slots -- far more calories to be had !

coffee time now...

cheers to all, thanks again for all the great inputs and feedback (Willie, however on earth did you come up with that Folded Riser idea, it is pure genius !)


G_H

 

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(1)  "Heat goes from hot to cold, there is no directional bias"
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mattie

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Reply with quote  #56 
You are 100% right with what your saying Stmbtwle with the drain back
My comment related the
elevated pressure in pipes with the rise in temperature ,what happens if the pump stops?

Will the pump run continuously or will there be a fill manifold in VSF with cold water and then waiting period for the water to take on the heat?

Surely there is a way to link the pump and check valve  and allow the check valve to turn off for drain back?

Am I miles of here with this or making some sense?
Regards Mattie
Garage_Hermit

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Reply with quote  #57 
Er, I think I can answer this one !

I perhaps did not make it clear enough that I am building an OPEN CIRCUIT drainback system...

If the pump stops (no electricity, or maybe pump just seized a bearing...), then the water in the pipes between the pump and the collector will lose its head, and run backwards to where it came from (= the Drainback Reservoir).  Under Gravity (because it has no other force to push it upwards).
So this is good, since the collector is now starting to get empty (which it needs to be - there is no pump, no circulation and otherwise the collector might boil...).

However, any fluid that is already in the collector MIGHT BOIL !  But even this is not a problem, because said fluid is "suspended in air" - the hydraulic circuit is no more... So even boiling hot, this fluid will still drain back down the lines (because the upstream (FEED) line is empty because the water in it has already drained back, as stated above...) OR it will carry on out of the collector, down the HOT (DELIVERY) line as per normal (because the DELIVERY line is open to air: it is an OPEN CIRCUIT -- the hot delivery line it is not plumbed into the HOT tank, the water just cascades in...). Hence, the circuit is "open" ( there is an hydraulic break at this point...).  SO you (might) get a big GULP of red-hot fluid in the HOT tank , but that is no issue, since it is what the hot tank is for...
=============
The difference is, in a Closed Circuit Drainback, you have a closed circuit - so how to open the circuit to let the water drain back, it would create a torricellian vacuum etc....

the answer is, you have a valve (or a vacuum breaker as Willie mentioned), that OPENS when the pump stops (either it opens under electric effect (current loss), or it opens under the effect of pressure (it is normally held closed by a spring, and the pressure in the circuit forces the spring and opens the valve...).

But like Doctor Ben said in his video, all this complex stuff is not required with an OPEN CIRCUIT...

============
In my rough layout, I place the Drainback Reservoir HIGH, so that it gets "first shot" at any returning fluid...

If the drainback Reservoir is LOW, and if it is not far enough from the collector, then there is a chance that the volume of PIPE between the collector intake and the pump, is insufficient to hold the entire contents of the collector... And if the pump seized, it might not allow drainback at all... Whence the "hi-&-close" DR...

For me, nearer and  higher is preferable to lower and further away
even if it does require the second pump...[frown]

apologies for the misunderstanding, guys...

G_H

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mattie

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Reply with quote  #58 
No problem all,
I like learning just as much as helping.
Regards Mattie
Garage_Hermit

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Reply with quote  #59 
Well, we might not have "BLACK FRIDAY" here in France, but perhaps I found a good deal anyhow ?

[image]
This is a "cellar dewatering pump", for the princly price of 22 Euro's (= 28 US dollars in real money...).

(frenchmen just *hate* flooded cellars...)

The bad news is, it draws 250 watts [redface],
but it *does* (supposedly) provide 8000 lph (= 35 US gpm)
and it has a head of 7 meters, which is pretty impressive...
(I need 6) (I  think...).

What I'm thinking, is giving this a try...

  • First step is to get the facade running on natural siphon, on just a single slot, using PEX
  • If that works, do more slots (I have NINE in all...)
  • if THAT works, then fix up this pump...

Because I reckon that natural siphon is going to be VERY slow...
I will likely have to use "half-inch" PEX (it is 16 mm OD, and 12 mm ID)

(if all of THAT works, then I will invest, and build Willie's Folded Riser All-Copper Manifold (promise) [smile]


All Opinions Welcome As Normal...

G_H

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(1)  "Heat goes from hot to cold, there is no directional bias"
(2) It's wrote, "voilà" unless talking musical instruments...
mattie

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Reply with quote  #60 
Nice find
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