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Post by patamos on Jul 15, 2019 8:21:27 GMT -8
Ya, I am intereste in hearing more about the water cooled heat exchanger you are working on.
Ive experimented with blower fans on oversized harvesting mass. Trouble was the rate of draft was not always optimal for the variable rates of combustion in a given burn cycle; at times making for too much residency, other times not enough. Co2 is heavier than ambient air, so at equal temperatures the exhaust gasses will want to descend. But this force may not always be enough to pull the gasses through a system oversized enough to harvest all that heat. Seems it would make more sense in a gymse or RMH where the push through the heat riser is strong and the burn rate is somewhat gradual.
ONe idea (for my above-mentioned build with only 4' drop) is to have both an ascending flue with the usual optimized harvesting system, and also a T junction with a longer run through an added harvesting element (water jacket, or extended earthen mass...) powered by an fan/pump that is tuned down to draw only some of the gasses.
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Post by gadget on Jul 19, 2019 18:59:19 GMT -8
Ya, I am intereste in hearing more about the water cooled heat exchanger you are working on. Here is the basic idea, copper is suppose to be good for condensing flue gases (I read it in a white paper on distilling wood gases). The best case scenario would be a large copper air to air heat exchanger that can be cleaned easily. My goal is to get the same performance using cheaply available parts. The only real expense is the copper pipe but it is easy to buy local. Since an air to air heat exchanger would be very expensive and not very common, I decided to use water as an intermediate to allow use of an automotive radiator. The copper pipes route the flue gases through the first barrel that is full of water. This water cools down the copper pipes and is circulated through a radiator preheating the air that is entering the heater. This outside air would be very cold in the winter allowing for some good cooling of the copper pipes. The lower barrel below would act as a container for condensates. There would be a pump to move them out to the drain. Pretty simple and should be very efficient. Most parts can be had for pretty cheap except for the copper.
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Post by jlmtech on Jul 26, 2019 14:39:53 GMT -8
Ya, I am intereste in hearing more about the water cooled heat exchanger you are working on. Here is the basic idea, copper is suppose to be good for condensing flue gases (I read it in a white paper on distilling wood gases). The best case scenario would be a large copper air to air heat exchanger that can be cleaned easily. My goal is to get the same performance using cheaply available parts. The only real expense is the copper pipe but it is easy to buy local. Since an air to air heat exchanger would be very expensive and not very common, I decided to use water as an intermediate to allow use of an automotive radiator. The copper pipes route the flue gases through the first barrel that is full of water. This water cools down the copper pipes and is circulated through a radiator preheating the air that is entering the heater. This outside air would be very cold in the winter allowing for some good cooling of the copper pipes. The lower barrel below would act as a container for condensates. There would be a pump to move them out to the drain. Pretty simple and should be very efficient. Most parts can be had for pretty cheap except for the copper.
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Post by jlmtech on Jul 26, 2019 14:46:42 GMT -8
Hi Gadget,I enjoy reading about your experiments. When I took chemistry many years ago, we were shown that a bunsen burner will not let a flame pass through a fine screen. A fine screen is used in chemistry to support container of chemicals above the Bunsen burner. The gas will pass through but the combustion of the gas is stopped. Also the the gas can be lit above the screen and fire gas would not pass down through to the nozzle of the Bunsne burner. Your ceramic screen may be behave the same way. The ceramic screen can be tested with a small LP torch.
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Post by rocketyurts on Dec 24, 2019 4:22:49 GMT -8
Hey there,
I couldn't fully figure out what you're going for but i have built a j-tube with downdraft pipes in a big bench and a steady drip of cendensation. Flue exit Temp is around 17-20°C. The declination is only about 10 cm from the exit of the barrel to the exit from the bench. Currently I attached bent (with a hole for the condensate to drip out) and a 3m riser because the steam would gather around my yurt with the mentioned sausage like smell ... I just started a thread to discuss this build here:
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Post by permaculturebob on Dec 31, 2019 7:26:05 GMT -8
Bill Mollison described a wood distillate recovery system in ancient China using the final horizontal flue of the "Kang" by simply locating containers at different sections of the pipe which would have had different temperatures, and the condensing liquids simply ran out a hole in the pipe.
So the stove not only cooked the evening meal and warmed the sleeping platform, but recovered various wood distillates.
I tried searching Kang for more detailed reference to this, but so far have not found the details of this recovery, only the cooking and heating aspect. I would guess this grew out of observation, trial, and error, using consistent types and quantities of wood/biomass over a long period.
If anyone has any references to this it might be interesting to study.
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Post by rocketyurts on Jan 13, 2020 4:21:06 GMT -8
permaculturebob I'm collecting about 125ml of Condesate per Burn. Do you have ideas what to do with it?
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Post by Jura on Jan 13, 2020 7:07:35 GMT -8
AFAIK 87% of the mass of the condensate is water but highly contaminated with PAH's. So in fact it should be treated as a hazardous waste.
I heard of ppl who dehydrated it (solar dehydration) and used such concentrated liquid as outdoor wood preservative. (mind its smell)
One of the options is to add it in small portions to a high-temp humanure compost pile as during maturation phase the microorganisms (mostly fungi) are capable of decomposing it (converting it into simple sugars and.. use it as their food...)
Paul Stamets is the key word if you are interested in low tech composting solutions
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Post by rocketyurts on Jan 14, 2020 10:33:13 GMT -8
Sweet! That's good information! Thanks a bunch! We're already composting our humanure (normaly around 50-60°C) and I'll just add the condensate there and when the temperatures start to drop it's mushroom food...
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