Heating the digester

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Jason Beers
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Heating the digester

  The main thing I have been thinking about lately is, "How am I going to heat my digetser?"  I have been looking into all sorts of different things from having a wood burner nearby heating water and circulating it around the digester to using my hot water heater with T's in the cold and hot side making a loop to heat the digester.  I would make a radiant floor part and also wraps around the side of the tank.  I have been watching the woes from others that post on here, and on the facebook page about heating them. 

  My conclusions at this point are:

  If the digester is outside, the Jean Pain method would work best in cold climates such as here in Pa.

  If it's located in a basement, as I am looking at doing, using the hot water heater to heat coils around the digester inside the insulation.  A small pump would pull hot water from the tank and circulate it back to the cold side of the tank.  As I am already going to be making more gas than I am using even in the current cold conditions, I shouldn't have any problem with adding the usage to heat the tank. 

  What are your thoughts on this?

Nick Chase
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Basement is probably far

Basement is probably far better than outside. You need a lot of material to create a Jean Pain, remember that Jean Pain had an entire forest at his doorsteps, where he could collect organic material to create wood chips. Putting it in a green house might not be useful if you have only 4 hours of sun in winter...

Insulating a digester is basically the same like insulating a house - the better the R-Value the better the temperature keep. You have to make sure not to create any thermal bridges. Most DIY builders simply put some foam, wool or other insulating materials around it.

TH, what do you think?

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Thomas H. Culha...
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It works.

Yes, basement biodigester is best and heating from a loop off the boiler/heater with a circ pump on a thermostat works great. We've tried it, we stand by it. We are also heating the insulation box with the hot air from the clothes dryer (but becareful of moist air causing mildew). Our latest technique is to experiment with self-regulating heat cable under the digester (maybe inside too) and with a 12V 300 watt heating element stuck through a uniseal in the middle of the tank. Will report results when we have them. Please do share what you come up with too! Welcome to our community!

Nick Chase
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Check out the 12V 300W

Check out the 12V 300W heating element experiment at http://www.solarcities.eu/blog/2016/04/469 . That's what Thomas is talking about...

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