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Old 11-06-09, 01:35 AM   #16
AC_Hacker
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Default Phase Change Materials

Quote:
Originally Posted by Christ View Post
So what I"m getting from that little graph there is that I can store heat in thermal tanks (like I had planned) but the best thermal fluid that's easily usable is probably going to be a salt brine, right?
The graph is saying a couple of things...

When you compare concrete and water as heat storage mediums, water has a greater capacity, per mass unit to store energy. So to store a given amount of heat, you would need less water... less than 1/4 the mass of water to store energy.

The graph also looks at the energy storage potential of calcium chloride hexahydrate, a hydrated salt. The graph indicates that this salt is about 50% better than water, and over 6 time better than concrete. What the graph doesn't make clear is that it is particularly looking at the phase change characteristics of of the salt, in other words the large amount of energy that is stored and released when the salt is heated and cooled between its liquid and solid state, which occurs at around 85 degrees F, which is very convenient for heating purposes.

The links I put in the previous post go into more detail about the interesting properties of PCM materials.

[NOTE: I just came across a PDF that does a good intro to PCM.]

Regards,

-AC_Hacker

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Last edited by AC_Hacker; 11-06-09 at 01:09 PM..
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