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Garage_Hermit

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Reply with quote  #21 
Quote:
(...) and I know the problems when the stuff hardens in the pipes.  


Idem - I nitrated toluene for a few years, so became somewhat acquainted with the practicalities and theories of heat-management...

After I left, my still base exploded and killed five people...  I think of them most days...

============

Good idea about wax for storage, and water for working fluid.

The incoming hot water would need to circulate through the storage via a battery, melting the wax as it went.  As the wax heats up, the heat exchange will tail off.

When the sun goes down, the water is diverted by a 3-way valve, to direct it from the storage, to a radiator / radiant system etc. - so no HW is circulated back out to the cold collector !

So this is radiant heating - not what the thread is about ([frown]).

For radiant cooling, you would need to be pushing warm air at an indoor absorber, all day (with the doors closed...), shoving heat into thermal mass (wax).

At night, you need to dump the heat out of the wax, into an external radiator, using the (same) water line.

Would only work if you live in a region where there is enough temperature-swing over a 24-hr day...

G_H

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stmbtwle

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Reply with quote  #22 
"The hot water would need to circulate through the storage via a battery, melting the wax as it went..."

What is this "battery"? Please explain.

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Willie, Tampa Bay
Garage_Hermit

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Reply with quote  #23 
Apologies if any confusion, Willie, the battery is a bunch of pipes, through which the water flows; it is akin to a boiler tube assembly...

as in figure 609 (near bottom of page...)
http://chestofbooks.com/architecture/House-Construction/Warming-And-Ventilation-Continued.html#.Vak4jLXgh9k

analogous with "tube bundle"

G_H

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stmbtwle

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Reply with quote  #24 
I know how boilers are made, and what a tube bundle is. But both of those assemblies deal with FLUIDS (water/steam) which will FLOW, and which will support convection. I'm not too sure how well that would work with cold wax.

Suppose you have this tank of warm liquid wax with a tube bundle in it. You run cool water through the bundle, and the wax around the tubes turns solid. This will inhibit convection and heat transfer, much like an iced-up refrigeration unit, which doesn't work well at all.

I'm sure it can be made to work, but I doubt it's anywhere near as simple as theory would lead us to believe.

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Willie, Tampa Bay
Garage_Hermit

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Reply with quote  #25 
er... You have to start with a HEATING cycle: so the water hitting the wax is HOT, like I said...

Then the HOT wax has to give up its heat, back to the water: the water has to be cooled in an external radiator.

sorry if my theory was not linear enough !

So the WAX store is actually operating like a crystallizer.

It could be made to work better by pulling vacuum over it; the warm air is then condensed over a condenser...
But now the simple domestic installation is taking on factory proportions...

G_H

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

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Reply with quote  #26 
It's a great idea, and understand how it's supposed to work, and I can find lots of articles on wax as an energy storage medium, but how to build one must be a closely guarded secret. Either that or it's so simple we're supposed to already know. I'm not about to spend thousands for a Latento tank, or even fifty for a "study" that may well be useless.

However I did find this  
http://www.ivt-rohr.de/en/solar-systems/all-year-solar-system/

Apparently in their tank a layer of "latent material" (wax?) simply floats on top of water in the storage tank.  That might be simple enough to do.  There's even a pdf with some diagrams that might be of use:  
http://www.ivt-group.com/fileadmin/Medien/PDFs/LatentoGanzjahres-Solarsystem_B_221113_EN.pdf

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Willie, Tampa Bay
Garage_Hermit

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Reply with quote  #27 
Nice find, Willie !

You ought to be able to reverse-engineer such a system, using your ARETHA, one of my wheelybins
[42610]
and a few gallon tins of floor polish, or even this...

G_H

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stmbtwle

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Reply with quote  #28 
I think any water-based solar collector would work, even Jeff's wood-fired boiler.   And it looks like most any hot water storage tank could be modified.  MIGHT be as simple as tossing in a hundred pounds or so of wax and letting it melt.

Relatively inexpensive too:  
http://www.firestartersonline.com/

Interesting thread on the subject:
http://forum.heatinghelp.com/discussion/126014/using-paraffin-wax-in-thermal-accumulators

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Willie, Tampa Bay
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Reply with quote  #29 
140 or so .5 litter water bottles 95% full of wax(or however many will fit) in a drum full of water would work fine, you just have to keep them from floating out.
once the wax is melted the water temp will just climb until it reaches the preset turn off temp.
stmbtwle

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Reply with quote  #30 
Hmmm the plastic bottles seem like a good option.  They would have more surface area than just a layer of wax floating on the water.  Price is right, too.
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Willie, Tampa Bay
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