The relatively large device described here (roughly the size of an bedroom-sized out-building (with construction guidelines included below) is around 12 feet square and 9 feet tall. It can easily create the continuous and constant heating that a medium-sized home in a cold climate like Chicago needs for an entire winter.
This presentation is primarily centered on describing how to build this HG 2 unit with locally available materials. Since there are a wide range of climates in the world, and sizes and types of homes, and an immense number of different ways this device can be used, many variants can be considered. If you want to learn more about how and why the HG heating systems work so well, the presentation at General Description may be useful. That presentation also has a link to a more comprehensive presentation which includes the Biochemistry and Thermodynamics aspects, which we think most people do not want to have to confront!
The Version 2 should not be built INSIDE the house, for several reasons. It is most convenient to be able to use heavy equipment to load the 16,000 pounds of material that commonly would be put inside it, where hand-carrying that much material to a device inside the house would be labor-intensive. Such large quantities of organic materials MIGHT contain an extremely wide variety of materials, some of which MIGHT either have undesirable smells to start with (like manure) or which might cause the generation of unpleasant smells. It also seems questionable to give up such a large amount of living space when it can be built as an out-building with nearly the same benefits.
Here again is an early experiment's temperature graph, where the rapid startup of activity develops in a matter of hours.
The basic Version 2 is NOT as high-performance a Version as the Version 3a is and the designed decomposition rate is around 3 pounds of the organic material per hour (creating around 27,000 Btus/hr of resulting heat every hour for an entire winter, sufficient to completely heat most entire homes through an entire cold winter). At 3 pounds per hour, all 16,000 pounds could decompose in around 5,000 hours, or around 200 days. (The Version 2 process tends to leave a moderate amount of Compost material when it has completed, so it is more realistic to think of having 12,000 pounds decompose over a period of around 160 days of a winter. That remaining material can be spread on a lawn or garden in the Spring as wonderful fertilizer.)
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For the past five years, I have often joked about how incredibly sensitive the Thermophilic bacteria are, where I sometimes have claimed that if you cross your eyes, all your bacteria might immediately die! Everyone else who has experimented with these devices has certainly felt great frustration at having to start the process over after you have done what seemed to be very minor harassments of your bacteria.
This is simple! During a TRAINING PERIOD while the owners are getting to learn how to properly supply the Thermophilic bacteria with the oxygen, the carbon dioxide and the heat they need to thrive, this idea is just so simple and obvious that I am very disappointed in myself for having taken five years to get here! You get an OLD (but safe) gas-fired clothes dryer. You connect the 4" vent duct to it and feed it into the chamber of the HG device. It is wonderful if you can buy a high temperature thermostat to put inside the HG 3a. Specifically, there is a very cheap type (around $5) which is called a disk thermostat. The rating that I like best is the one at 135°F. Any local heating-plumbing store should have that for $5.
So here is what happens. You toss ANY collection of organic materials into the HG 3a chamber. Just the tossing of cold material into the unit have been able to cause the bacteria to all die! They are AMAZINGLY sensitive!
Where it had always been critically necessary that you be extremely attentive to temperature, oxygen and water, or else you would off your bacteria, now it is entirely different! When you first close the door, the material is still cold, about the 70°F material that you had just tossed in. But since the thermostat recognizes that it is NOT warm enough in there, the gas burner of the clothes dryer turns on and also the motor which blows the hot air through the vent pipe also turns on. In other words, in just a few seconds, you have started to ARTIFICIALLY heat the entire interior of the HG unit up to around 140°F. It turns out that You have actually also provided OXYGEN for them at the same time!
Your Thermophilic bacteria are as happy as they could be! You won't be able to see their tiny little smiling faces, but trust me on this one! Of course, the actual point of this whole thing is that the bacteria start decomposing organic materials and creating a lot of heat. As soon as they have begun generating enough heat to keep everybody happy (which is surprisingly fast), the thermostat sees that there is no longer any need for the clothes dryer to run any more. Actually. just three to five minutes seems to be all it could ever need!
AND the reasoning is that YOU will LEARN how it is all to work, and you will likely never again need to use the clothes dryer for the artificial heating. Or maybe, only very rarely! Basically, the only time that it would then ever need to turn on again would be if you have forgotten to load the unit or something similar!
I think that as the owner learns how to make fewer mistakes, it might be less necessary to be providing this additional artificial heating, as the Thermophilic bacteria are perfectly capable of producing amazing amounts of heat on their own! You might note that I might be sounding somewhat insulting regarding ARTIFICIAL heat! It's true! I am sort of a purist on this, and the fact that Nature has created the amazing Thermophilic bacteria, it seems to me that we have some sort of responsibility to learn how to provide for them. Think of it as not having just one pet dog, but many billions of pet thermophilic bacteria. Take care of them and they will take care of you!
Personally, I like the safety aspects of the fact that the natural HG devices do not involve any flame or fire, and that the sopping wet contents ensure that no dangerous fire could possibly ever happen. But as a Training Aid to Rookie owners of an HG device, I guess I can tolerate a tiny amount of fossil fuel consumption, BUT ONLY UNTIL YOU LEARN YOUR CHOPS!
Either gas-fired or electric clothes dryer should be able to keep your bacteria cozy and happy. In any case, the 4" dryer vent is fed into the HG chamber. (No, I think it would be a terrible idea to also try to dry clothes in it, as you would then be ignoring the well-being of your bacteria!) But then a temperature sensor (or 135°F thermostat switch) inside the chamber could automatically turn on the clothes dryer to send some really hot air into the chamber, which also would provide extra oxygen for the bacteria's enjoyment! Once the owner learns how to operate the HG properly, the thermophilic bacteria inside will generate plenty of heat so that the thermostat switch would never again need to turn on the clothes dryer!
Given my personal experiences with killing off a lot of bacteria over the past five years, this modification seems excellent. Of course, the usual safety precautions need to be attended to. IF you have very dry bales of grass or hay, stacked somewhere near your HG device, you CANNOT ever leave any such material very near a fire-containing clothes dryer which might turn itself on! Got it?
Nearly any organic material can be loaded into a Version 2 device. Cut lawn grass and Autumn leaves are always locally available for free, but hay, straw, corncobs, sawdust, weeds, garden or field crop residues are also obvious sources, depending on local availability and cost.
Relatively thin tree branches can also be loaded, although the THICKNESS of the pieces can greatly slow down their decomposition.
Even materials such as used motor oil or animal manures can be loaded, although each type of material has its own characteristics regarding decomposing.
It is certainly possible to make even larger scale versions of this Version 2 system, for heating larger commercial buildings.
Cooking does NOT seem possible inside a Version 2.
The floor structure is a simple framing pattern using 2x8 lumber
and a standard 3/4" plywood subfloor. It is made to be 12 feet
With the subfloor nailed on top, the floor would look like this.
It may be possible to make the inner bin slidable across the floor,
and so it might be important that it be flat and smooth, for any
rollers which may be able to roll the bin back and forth across
We can then build the 2x6 walls, again using standard practices.
We will build the walls to be standard 8 feet tall. Notice that there are
only three walls built, with (this) front wall entirely missing!
An important detail is that the boards surround that front opening
be all flat and plane, as there will later be another (movable)
structure with some gasketing on it that will slide in to be against
that opening to seal it up.
ALL of the inner surfaces of the building have conventional fiberglass house insulation installed, and then they are all covered with EITHER cheap paneling or even drywall. The important fact is to make everything air tight, where no heat can leak out.
There are two obvious approaches to this structure, with several other variations possible. We will briefly discuss here making a bin out of wood, but prefer metal. The metal version would be more durable, and have far better short-term energy heat exchange performance. The wood version might be worth a first stage to try, even though you know it may only last a year or two. It seems to allow many more options and easier changes to experiment with different arrangements of the components. So we will first discuss a wooden bin.
Basically, we will make a bin that can fairly easily fit through the eleven-foot wide and eight-foot tall opening. We will want to consider having it on some sort of rollers so that the rather heavy filled bin can be slid into place after more easily filling it outdoors. This might make the difference between being able to use a farm tractor or Bobcat and having to toss in the material by hand. However, rollers might be a problem in that the bin will contain around 16,000 pounds of organic material, so the filled bin will weigh as much as six automobiles!
We suggest making the bin ten-feet wide so that it has about six inches clearance on each side as you are moving it. The height of the bin would be just under eight feet. This would give a metal bin the inside dimensions used above in the performance calculations. (Obviously, a metal bin would be larger inside than a wooden one.)
The FRONT wall of the bin needs to have flanges extending outward on both sides and across the top. This flange will have standard door weather-stripping attached to its rear side. In this way, once the bin is slid completely in place, that area overlaps the building door frame for a good tight fit. This vaguely resembles the way a dresser drawer overlaps the dresser body hole, but without any gasketing!)
None of the walls of the bin are insulated EXCEPT THE FRONT. The front needs to have at least R-19 insulation. One possibility for this is to make the front out of 2x6 lumber instead of 2x4 or 2x3 as the rest of the bin would be built of, so that it could have fiberglas R-19 insulation installed in it. Another possibility is to use BLUE foam house insulation, in several layers so that it is 4" thick for R-20 insulation.
The bin must have some special features.
To start with, none of them are in the bin, and filling is begun. Once the organic material got up to around the height of the lower pipes, they would be slipped in through the front hole and jammed into the closet flange. (The bought 10-foot-long pipe having been cut so that it extends about 6" past the front outer wall.) The holes in the pipes should be lined up top and bottom. More material is tossed in the bin, and the upper pipes slipped in at the appropriate time. This allows filling the whole bin without any void spaces under the pipes. When the whole process is done, these pipes may be easily removed so that the resulting humus can be removed from the bin so the next filling can be made.
Water flow rate might be experimented with. A very slow flow tends to cause most of the water to drain out through the first hole in the pipe, while a surge of water tends to go all the way to the end and pool there before draining out at the last holes. A mid-flow-rate can get water to drain out fairly equally along the dimension of the pile.
These thermometers are so cheap that three different thermometers could be installed in the same pipe, such that the sensors were 1/4, 1/2 and 3/4 of the way back across the bin. It would then be possible to monitor how evenly the decomposition was occurring, as even temperatures would indicate consistency while great differences might suggest that something was not ideal.
The second of these two electronic components is a humidity sensor. Only one of them is probably needed, for the very center of the pile.
There are many ways this can be provided. One obvious way would be to buy several "Earth augers" which would be installed parallel to those piles, with their end sticking out the front wall. At any point where it was felt that it would be beneficial to turn the pile, a wrench could be used to rotate each auger shaft, which would turn the auger inside the bin.
Given that this should be a minimal need, it seems that a far more economical approach might make sense. Get several more of the PVC pipe, but drill 1/2" holes through opposite walls, such that a foot-long piece of 1/2" metal rod could be stuck through and secured. The result would be the pipe having 4" long Barbs sticking out from opposite sides of the pipe. If maybe a dozen such rods were securely attached through such a pipe, and the pipe was installed similar to the air pipes discussed above, a pipe wrench on the stub of this pipe sticking out would be able to rotate it, which would force those barbs to stir up the material in the bin.
Higher-tech and more expensive variations of this are obviously possible. It is tempting to wonder if the air pipes could also handle this duty.
If that temperature does not rise or drops, check the humidity, to make sure it is in the 40% to 70% range. If it is low, add water. If it is high, you have added too much water.
If there is the smell of ammonia, that is an indication that you are not providing sufficient oxygen for the aerobic decomposition to fully occur. It is an indication that you probably need to add more air. Depending on what materials you use, they might stay tangled together (as hay seems to tend to do) where the air/oxygen cannot get to some parts of the organic material. This could indicate that the material needs to be stirred up or turned over to break up such clumps of material. The supply of air/oxygen and its ability to get to all the material is probably the most important factor to maintain.
If the humidity seems fine and the temperature starts to drop, the only additional thing you could do would be to turn the pile, to stir up the organic material, in case some of it had not had good access to the oxygen or the water.
If the temperature drops anyway, after an extended time, it might mean that the thermophilic part of the process is done.
If the temperature starts to rise too high (above 150°F) then you need to NOT encourage the thermophilic bacteria! But you could try to send more (cold) air through all the pipes to try to chill down the reaction.
To some extent, you need to find out how your own system responds to such things, so you can learn how best to help or slow the process in the future.
There is one other possibility. If you put in things that will only decompose slowly, such as tree branches, OR if you neglected to toss in organic material that contained sufficient nitrogen, the bacteria may not be able to fully thrive, and the temperature will never rise very high.
You can probably see that there are an immense number of variations possible in using this system!
We chose the insulation levels to provide limited losses while considering reasonable expense. You can use this same approach to see whether you might find any value in increasing the insulation to R-30 or higher.
Note that this small room/building must NOT be inside the house (mostly because of the possibilities of odd smells from the decomposing materials depending on what you pitch into it) but it should be as near the house as possible to shorten the ducting or hydronic plumbing connections. Those connecting ducts or pipes need to be extremely well insulated, at least R-50 and higher if possible.
The small building should probably have a standard peaked roof such that rain would not stay on top and leak through.
If this is set up as a "forced-air" installation (Version 2), two large ducts must connect the house with this building, a cold-air-return and a warm-air-supply. They would connect into the house ducting in very conventional ways. It can also be set up as a PARALLEL heating system to an existing conventional furnace, where a separate furnace blower is used.
The existing standard wall thermostat would now simply turn on the furnace blower. It would blow house air out through the one large duct into the space between the bin and the highly insulated building walls. This creates a pressure which pushes some of the warm air in the building into the other duct, and back toward the house. That heated air (actually much hotter than normal furnace air normally is, commonly 150°F instead of the 120°F of most conventional furnaces) then goes into the existing duct system and is distributed to all the rooms of the house.
As the heated air is removed from that space outside the bin, the metal walls of that bin act as heat exchangers to transfer additional heat into the air. We have provided a very large area of this heat exchanger surface (420 square feet) and the material inside the bin remains near the 150°F temperature, and so the additional (relatively cool, 65°F) house air that is sent to this building is quickly heated up, to provide a constant supply of nicely heated air for the house.
We should use this larger number regarding the exhaust in designing the airflow through the system. It is still a rather small air flow rate, and even a small blower would rarely need to be turned on. We could reduce the actual airflow, with the main effect being that there is then still a lot of carbon dioxide near the bacteria, so they can less easily get to oxygen, which can slow down the process. In other words, we can have a moderate level of control as to how efficiently the bacteria are decomposing the material in the chamber by how regularly we have the small blower pushing new air/oxygen into the chamber. We may also want to triple that capability, in case we should ever want it to decompose the maximum desired 10 pounds per hour, which means we should provide airpath sizes where 63 CFM of air can pass. We choose to use a 4" dryer duct size of connection for the airflows, along with a very small blower (in the INLET side) which can easily move around that level of airflow. This is actually a convenient size, as it means that commonly available flexible dryer vent hose can be used if we want to direct the exhaust to a nearby greenhouse.
The (existing furnace) blower used to drive air into the chamber would ensure that sufficient flow rates are present. The 4" PVC exhaust pipe would here extend to outdoors, much like the PVC exhaust of a modern high-efficiency condensing furnace, OR into a nearby greenhouse where it can have wonderful benefits. This approach eliminates any chance of odors entering the living space. The overall efficiency for the house can be improved by sending the 150°F exhaust gases (containing water vapor and carbon dioxide) through a fairly simple heat exchanger, to capture that heat AND the energy that can be recovered when the water vapor condenses into water. THAT is the concept of the high-efficiency condensing furnaces in modern homes, but this system can accomplish it with a far simpler and less expensive heat exchanger.
The Version 4 device is essentially the same but it heats up large amounts of water rather than air. In this case, two highly-insulated water pipes connect the out-building to the house. One brings RETURN water from the hydronic circulating pump, which sends the water into the water chamber in the out-building. The other pipe sends the already heated 150°F water back to the house to be then distributed to various rooms by the existing hydronic piping system. Standard conventional hydronic heating room radiators can be used. Even (ugly) car radiator(s) could be used for the heat exchangers for this approach.
If good quality lawn grass is cut, the blades of grass tend to be in the 0.05" inch thick range, and they begin to decompose amazingly quickly, in just a few hours.
If FIELD grasses are collected, the blades may be twice as thick and so the process is slower, often around half as fast.
If farm hay is used, performance is generally comparable to field grasses.
Most autumn tree leaves seem to be about as thick as cut lawn grass, so they are able to decompose rather quickly.
If sturdier weeds, and especially larger and thicker weeds are used, the process is slower, generally in proportion to the THICKNESS of the pieces.
If farm straw is used, performance is generally comparable to common weeds.
If even small twigs are included, their greater thickness tends to cause far slower decomposition, again roughly in proportion to the thickness of the twigs. Quarter-inch thick twigs can be expected to take most of a week to decompose.
Thicker branches take even longer. One-inch thich branches seem to take as much as a month to decompose, although it seems to depend in species of wood, with softwoods being faster and hardwoods being slower.
Putting any pieces of wood thicker than one inch seems inadvisable, because of how slow they decompose.
You can estimate the rate for any other types of organic materials by the above guide. For example, sawdust generally has rather thin and small dimensions, and it (rightfully) can be estimated to decompose very fast. Newspaper CAN if the sheets can become separated, but if the newspaper is rolled up or otherwise compact, its decomposition can take quite a while.
There are certain exceptions. Egg shells tend to take a lot longer to decompose than most other things of their thickness. It appears to be due to their high density and probably the calcium in them. Plastic bags tend to take quite a while to decompose, although the reason is still unclear.
Here's an example, of hundreds of such things that we know about. In the late 1970s, someone near Detroit bought one of the JUCA woodstove/furnaces that I manufactured. As was usual, he easily heated his house entirely, and like other JUCA owners, bragged to relatives, friends and neighbors that he was no longer paying any heating bills (where they were!) A neighbor soon bought his own JUCA to eliminate HIS heating bills. We knew nothing about all this for around four years, at which time he called us to register a complaint. Since that was the FIRST complaint that we had ever received regarding a JUCA's operation, we were extremely interested in knowing why it was not doing as he was expecting. He said that the neighbor's whole house was very comfortable, while his had many cold rooms, and also that he was using around 20 cords of wood (while the neighbor was using about 4 cords to completely heat his house for the entire Detroit winter. It was very puzzling! After probably twenty long phone calls, where the owner always insisted that the unit was EXACTLY LIKE the neighbor's [but faulty] we still had no clue as to why he was not getting the normal massive JUCA heat. But finally, I happened to ask him regarding confirming that he could press his hand against the JUCA for at least a minute while it was operating. He laughed, and said that he did not dare even touching it for a fraction of a second!
Since we had learned by then that a lot of housecats discovered that sleeping on top of the JUCA was a cozy place, this was clearly very strange. We asked the logical next question, regarding WHICH JUCA blower he had been using. He was puzzled by that question! He said that the blower was STILL IN THE BOX! He said that when they received their JUCA, it was bigger than they had expected it to be. When it was also necessary to mount the blower on the back of the JUCA unit, which causes the JUCA to be around 10" (or more) farther out into the room, they DECIDED not to use the JUCA blower! For four years, they had been trying to operate a JUCA without even having a blower on it! (JUCAs are all forced-air furnaces, which REQUIRE the blower to be operating nearly all the time. In fact, they decided to push the (big) JUCA completely against the rear wall, which even blocked off the opening where the blower should have been mounted. So the unit could not even thermo-siphon to circulate the warm(hot) air naturally!
They had done absolutely everything possible to defeat the proper operation of the JUCA unit! For four years before complaining to us! It is actually astounding that they did not burn their house down, since they therefore had a large unit that was so hot that they feared touching it, pressed right against a rear wall!
It turned out that since he knew that the neighbor was entirely heating his house with his JUCA, he decided to just constantly be loading wood into his, to try to match the performance!
Too bad he never read the Installation Instructions or the Operator's Manual, which both make crystal clear that the blower MUST be running nearly all the time.
We later discovered that the neighbor had also bought an optional (larger) JUCA blower which is necessary to feed the WARM air through the house ducts to all the rooms. This customer didn't see any value in a blower in the first place, so he certainly would never have seen cause to get an even BIGGER blower (which would have pushed the JUCA even farther out into the room!)
It would be one thing if there had only been one such customer who entirely ignored all instructions! But over the years, we learned that that joke about the Christmas bicycle is actually very commonly true! So, a Disclaimer! IF you choose to follow the construction instructions (above) fairly well, the HG 2 or HG 4 unit will work like a charm. However, if you greatly alter even ONE major characteristic of it (without actually knowing enough Engineering to be able to actually calculate the proposed improvement), you are on your own!
(2) An immense number of people seem to not comprehend the concept of a GIFT! The exact same thing occurs in the Free Air Conditioning web-pages, which I have provided, FOR FREE, since late 2000, where all the necessary construction and planning information is included, as well as all the information regarding the Engineering concepts behind why it works so well. However, so far, over SIX THOUSAND PEOPLE have DEMANDED that I provide them PROOF that it works! Several thousand others have demanded that I give them names and addresses and phone numbers of some of the 9,000+ people who have installed and are using the (Free A/C) system. The same is already starting regarding this HeatGreen heating system.
This information is provided by a fairly intelligent Nuclear Physicist FOR FREE! I thought that was a nice and generous gesture! WHY do people think they deserve to get "free custom personal Engineering" or to receive whatever they might consider to be proof or to be allowed to annoy some happy family with hours of endless questions? This DID used to sometimes happen with the JUCA Super-Fireplace whole-house-heating woodstove that I DID actually sell for many years. The owners nearly always found it very annoying, except for people who THEY INVITED to their homes! But when a CUSTOMER was considering BUYING A PRODUCT, it seemed vaguely credible that they might want to annoy owners of my woodstoves like that. A woman from Alaska ended that! She DEMANDED that I give her a dozen names and phones of owners (who had each generously offered to talk to potential customers). I expected her to pick out one of the twelve, and then to make a politely brief phone call. But NOOOO! She spent a dozen evenings, calling each of those families for phone calls which I was told were all between two to three hours! The entire quiet evening for a family was gone for every single one of those wonderful families! (All that to consider buying a $1400 woodstove which we had GUARANTEED [since 1989] to be able to ENTIRELY HEAT ANY HOUSE.) But she alone managed to infuriate all dozen of those people, each of whom then immediately asked to have their names removed.
A single inconsiderate woman really destroyed a fine way that JUCA owners had been previously able to help people who are not familiar with the performance of JUCA units. Unbelievable. Now, do YOU think that I am going to put ANYONE at risk of having that happen to them, WHEN THERE IS NOT EVEN ANY PRODUCT BEING SOLD?
(I may have a very old Bridge in Manhattan to sell you if you do!) But separate from that, apparently no one has ever heard of the Gift Horse story! For the Free Air Conditioning, and for this HeatGreen system with its several configurations, and with the free system to monitor Children's Bodyfat in a fun and easy way, and in the method to try to drag Beached Whales back to the ocean, and on and on; IF you demand PROOF, then I would PREFER that you simply go away and stop bothering me. Go stare in the mouth of some horse somebody has offered to give to you! In fact, I make VERY sure that I provide massive Engineering and scientific proofs for each of the statements made regarding any of these systems which I offer.
You actually DO have access to a way to PROVE that the HG2 or HG4 or the Free A/C works as described. You could HIRE a top quality Thermodynamics Engineer (at around $400/hour), and he/she can then duplicate the Engineering which I provide for free in the web-pages. A talented Engineer should be able to research that my information is sound and then calculate the needed things in maybe 25 to 40 hours of work. Of course, this means that you will have to pay that Engineer between $10,000 and $16,000 to confirm the information WHICH I HAVE GIVEN YOU FOR FREE!
All in order that you not waste $200 on building materials from a local store to build an HG 3a unit!
I can only say, DUH!
Please do NOT be annoying me with demands for proof (before you dare spend $200 for materials), OR where you will insist that YOUR application IS UNIQUE and you therefore REQUIRE me to personally Engineer (the exact same unit) for your needs. IF you are willing to pay me at that standard $400/hour rate for such advanced Engineering, and will provide a Retainer for a number of hours to start with, I MIGHT be willing to listen. But probably still NO! If you are so convinced that you have a totally unique situation, then get that local Engineer to do the Engineering and Design for you!
IF you have such total doubts about these systems working, then you either haven't actually read most of this documentation or you do not deserve to benefit from it!
C Johnson, Theoretical Physicist, Physics Degree from Univ of Chicago