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Wood Gasification : Heating Aquaponics Unit  RSS feed

Dan Popovici
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Hi Ben,

I would like to use a wood gasifier to heat up the water in my aquaponics system. I want to make sure the water in the aquaponics unit doesn't get below a certain temperature.
I'm thinking of the following design :
1) Use the wood gasifier to heat the water in a 275 gallon insulated tank.
2) When the temperature in the aquaponics unit drops below a certain temperature, allow the water from the heated tank to be part of the aquaponics system
3) break the connection between the aquaponics unit and the heated tank when the temperature is high enough

Now a few questions :
1) Does this design sound reasonable ? Any suggestions on how to improve it?
2) How long would it take to heat up a 275 gallon tank to close to boiling temperature?
3) I want to minimize the amount of time I spend daily to start the system. How much time does it take to get it started (assuming one has all the wood cut to size beforehand) ? minutes?
4) How complex of a wood gasifier would be needed if the only goal is to be able to heat up a tank of water of 275 gal in a reasonable amount of time?
5) Does your book describe how to heat up water with a wood gasifier?

Ben Peterson
Posts: 49
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1) Sounds reasonable to me. Since those tanks are plastic and you need to burn gas to heat the water I would have a heating loop with metal lines and a burner a few feet away from the tank. Use refractory bricks to trap the heat.

2) Depends on the starting temperature of the water and some other factors like gas flow, but 3 hours should do it 9 months out of the year. Longer in the dead of winter.

3) With a good char bed from your last run, a gasifier can make flammable gas in 5 minutes and be up to operating temperature in 10-12 minutes. That startup time is a good time to use the flare gas for heating.

4) You could get by with a very simple gasifier, you just need to decide if it will be a vacuum pulled gasifier or a pressure fed gasifier or some combo of each. Its easiest to start with suction, but you don't want to pull a bunch of junk through your blower, so it would be ideal to switch to a second blower that pushes in air and shoots out unfiltered gas ready to burn. A big scary blowtorch is what it will look like.

5) Unfortunately the book doesn't cover that topic. Maybe a future blog post can address it.

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