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Old 04-23-11, 04:30 PM   #8
go4haudio
Lurking Renovator
 
Join Date: Apr 2011
Location: USA, FL
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A more practical approach for the average home must be used. Large scale compost mounds provide plenty of food and water for the bacteria but do a poor job aerating the culture medium. A home scale composter would require effort periodically but its heat output would be much faster with less wasted heat radiating needlessly. The effort to compost would be far less frequent than the effort used in stoking a wood stove. Here is one example High-Performance HeatGreen Home Heating System Version 3a you might enjoy reading. Here is located a picture of his device. http://mb-soft.com/public3/zl30a16.jpg One weak link in this device seems to be that it regulates over temperature conditions with increased airflow. I quote "Take this last example, of the maximum performance which I have seen in an HG 3a, around 90,000 Btu/hr. It turns out that with the MINIMUM NEEDED AIRFLOWS we calculated above, the air inside the chamber would get FAR TOO HOT, and you would kill the bacteria in yet another way. Nothing to really worry about, because few people seem to get to that point yet! And installing a thermostat inside the chamber to turn on the blower switch at 150F, will keep you from frying your bacteria!" He goes on to postulate that a heat exchanger to regulate the incoming air temperature would be needed in these conditions. A heat exchanger is needed I admit to increase overall heat retention. However my proposed method to regulate heat excesses involves a heatpump, perhaps even a homemade heatpump such as can be found in this Ecorenevator website http://ecorenovator.org/forum/geothe...manifesto.html The entire process could be monitored and controlled by an arduino type computer device to be most self sufficient. The heat pump would draw heat from a large capacity insulated water tank that is hydronically connected to the composter. Regulating the heat out put is achieved by two things. First the computer chip can regulate the airflow to the bacteria. Second the choice of composting material can regulate the rate of digestion. For instance fresh grass clippings digest far more quickly than wood chips. Full implementation would be complicated and would not be cheap. But once constructed one would merely feed and water ones bacteria and less frequently clean out a little top quality humus. For many people a less complicated set up would be more appropriate. I will out line that in my next blog. Either approach would benefit from a "Bioshed." The Bioshed would be a shed in which The composter, the raw materials, a water tank, and all the necessary plumbing could be housed protected from the environment.
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