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Gray Edwards

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Reply with quote  #11 
Dan - I am talking about leaving them in the water..they are "part" of the storage in the tank.  Something that has a higher specific heat than water, thus would store more heat for the same volume.

Garage_Hermit

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Reply with quote  #12 
yeah, but like Dan says, the bricks would displace water.

Bricks are "somewhat more expensive" than water, and they hold less heat.

A cubic meter of water (1000 liters) costs me 1.3 Euros, which is about 1.5 USD.

The bricks (perforated) on the other hand, cost 63 euro cents each, and I need 800 to make a cubic meter.
that makes 505 Euros, or 385 times the price of the water...

The specific heat of brick is about 0.2:
cf.   http://www.engineeringtoolbox.com/specific-heat-capacity-d_391.html

Therefore the comparative cost-inefficiency factor (for me) of brick in relation to water is of the order of 4000...

G_H

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Gray Edwards

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Reply with quote  #13 
GH - 

1 - I was using the term brick generically, not necessarily a clay brick.  Some material that would be better than water.
2 -  Remember, specific heat is based on mass, not volume.  So you have to figure that into the equation.
3 - Surely you can get clay bricks for free anyway
4 - Isn't it about 2 am your time? WTH are you doing up?  LOL
Garage_Hermit

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Reply with quote  #14 
Hi, Gray,

Well, if you look at that list, there are not many substances that have a specific  heat greater than 1...

That is why water is Number One [biggrin]

G_H

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solarusmc

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Reply with quote  #15 
man... if we could just get like 150 people to stand next to each other in our basements each night during the winter we wouldn't even need a furnace!

figure... 150 x 98.6 degree body temp radiating up thru the floor, hellO? [wink]

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Pat B. Warwick, Rhode Island Rest Assured! Comments and/or suggestions I make here at the forums on 'your' projects as well as my own have all been carefully and scientifically calculated by the 'seat of my pants'
stmbtwle

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Reply with quote  #16 
You left out all the hot air they would generate! [biggrin]
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Willie, Tampa Bay
involute reflection

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Reply with quote  #17 
wax has a  heat of fusion of 25 and common melting points of 140 f for hard wax and 120 f for soft, I submitted a neat coffee cup to invention quest a few years ago that used this principle to cool your 180 f coffee to 120 f quickly and then keep it at 120 for about an hour in a double sided cup.


 you can store 20 times as much heat in the same space as water by using wax, but only in the change of state temp range, performance will quickly drop of as the wax hardens.
stmbtwle

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Reply with quote  #18 
That would be great, but dealing with a material that won't flow complicates things for me. Getting heat into and out of a ton or so of wax on demand and moving the heat to where it's needed is going to be more complicated than keeping a cup of coffee warm. Just how we would do this??
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Garage_Hermit

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Reply with quote  #19 
you would need steam tracing: the thing is, generating the steam (= change of state...) would use up more energy than would be produced by the change-of-state produced in the wax...
It's the fifth law of thermodynamics: "free lunches can neither be created nor destroyed".

G_H

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stmbtwle

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Reply with quote  #20 
That's my problem.  I've worked with liquid sulfur in my career and I know the problems when the stuff hardens in the pipes.   

Wax might be melted with hot water tracing but it still adds a complication most of us don't need to deal with.  An alternative might be to use hot water as a "working fluid" and wax simply for storage.  However how do we get the heat from the water to the wax and back?  Coils of copper tubing in the wax tank MIGHT work, but how to set them up?

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Willie, Tampa Bay
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