Modifiying fireplace

[Sillyboy]

I want to share you with you guys this simple and cheap method of adding heat storage capacity of a fireplace.

I did this to my sauna stove..to keep it more warm in the winter.

After this modification sauna was also more pleasant to use.

[TomW]

silly;

So, how many pounds of stone there?

How many BTU do you figure it "stores"?

Just curious.

TomW

[Sillyboy]

Maybe about 50 kilos. 3 g / cubic cm

This would mean 16666.666666667 cubic cm of stone

Heat storing capacity is 3 J/cubic cm K

If the stones are heated to 150 degrees celcius from 10 degrees celcius...

the energy stored to the stones would be about 2 kwh.

We usually warm up the stove every other day during the winter time, so

150. times - 45 (summer) = 105 times a year.
     
105. *  2 kwh 210 kwh.



Electricity costs about 0.1 eur per kwh.

At the end savings would be 21 euro per year.

Since the materials were free, the only cost would be work.

Say 10 euro per an hour..that would mean payback in one year.

Hope i got the calculation right.

They use this same method in commercial applications too.

In these applications the whole stove is wrapped in

stainless steel net and the gap is filled with stones.

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