Numbers.....

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Sean Trost

Member
Jul 17, 2013
4
ohio
Hey all I am getting ready to source and install a radiant floor heat system. I hope to utilize a pellet boiler with unpressurized storage.

Design intent is as follows....

convert from electric heat to pellet....(I dislike firewood cutting and such)
cover the time away from home ( I work 24 hr shifts)

some numbers I have come up with

heat load for the house 47520 btu/hr rounded up to 50000
2200 gal storage tank at a design temp of 170 F = 3104200 btu

3104200/50000 = 62 hrs of storage or 2.5 days

using 50000 btu to recharge said tank will take approx. 26 hrs at 70% efficiency.

using those numbers I have come up with a 100000 btu/hr needed for a boiler.

comments suggestions and or critics welcome and requested !

Thanks in advance !
Sean
 
With any state of the art modulating pellet boiler (Windhager, Fröling, ... ) I would suggest 80 or 120 gal of thermal storage at max.
1 gal per 1000 BTU.
 
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With any state of the art modulating pellet boiler (Windhager, Fröling, ... ) I would suggest 80 or 120 gal of thermal storage at max.

Said boilers will also do a lot better than 70% efficiency.
 
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Thanks all !
while a modulating boiler would be ideal. that is just not in the budget.
I am looking more along the lines of burning at full capacity like a gasifier and dumping the waste heat into storage.

I was conservative with the 70%
Sean
 
Hi Sean,

that is just not in the budget.

Do you mind sharing what your budget is?

heat load for the house 47520 btu/hr

Did you run the calculations to arrive at this number or is this based a known usage history? If so, how many Kwh for the heating season? And what is your per Kwh rate?

If you haven't already, it's worth considering a couple well placed mini split heat pumps. In Ohio You should be looking at a seasonal COP of 3+ with the better units. I bet cost per btu will very competitive with pellets. Plus you'd get extremely efficient AC. And if you are a capable DIY you could install them yourself for further savings and just hire an hvac tech to do the final hookup/charging.

Noah
 
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