Home Heating System = Version 3ab - High-Performance HeatGreen

Benefits of this HG 3ab system include:
  • Never pay heating bills again!
  • Great for the Environment!
  • No burning, no fire, no flame at all!
  • Never use fossil fuels again!
  • Build it yourself for around $200!
  • Step-by-step Instructions included here.

BETTER than Biogas!

This "active" version of the HeatGreen system has great flexibility and sufficient capability for nearly any residential heating application. It is absolutely "green" and eliminates the need for any buying or using of any fossil fuels.

The HeatGreen 3ab unit described here is identical to the HeatGreen 3a unit described at Alternative GREEN Furnace - Construction High-Performance HeatGreen Home Heating System Version 3a Construction Instructions for the HeatGreen 3a System, with one significant difference. Instead of the weight of the unit being supported by an axle, and instead of using that axle as the method to rotate the entire drum, the 3ab unit has no such axle at all! The unit is built very similarly, except regarding the axle and the air duct connections, AND the fact that this chamber RESTS ON TOP OF FOUR pillars, posts, or supports. The chamber of the HG 3ab device does not need to rotate!.

The relatively small device described here (roughly the size of an upright piano and weighing empty around 140 pounds) (and with all construction instructions included below) is around 5 feet in diameter and 2 feet thick. It can easily create the continuous 45,000 Btus per hour of constant heating that a medium-sized home in a cold climate like Chicago needs in January or February, and has shown that it can easily produce twice that amount of heat, or over 90,000 Btus of hour.

Public Service
Self-Sufficiency - Many Suggestions

Environmental Subjects

Scientific Subjects

Advanced Physics

Social Subjects

Religious Subjects

Public Services Home Page

Main Menu
This presentation is primarily centered on describing how to build this HG 3ab unit with around $200 of 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, we will include an assortment of simple calculations and explanations, such that each locality or each person could modify the standard HG 3ab unit for specific needs. 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!

As noted above, the standard HG 3ab unit is relatively modest in size, for several reasons. It is designed to be light enough when empty (140 pounds or so) to easily be carried or rolled! It is designed to be of dimensions where standard-sized pieces of plywood are very efficiently used with very little waste, and also so that it can fit through standard doorways. It also is designed so that when completely filled, it does not weigh much more than a filled food freezer, and therefore will not stress building floor structures. The dimensions provide an inside capacity of around 40 cubic feet, so depending on the density of the organic material used, around 400 pounds (at 10 pounds per cubic foot dry density) to 800 pounds (at 20 lb/cu ft) of material usually can be put into it at a time. (Certain materials like sawdust or feed corn are of higher density and greater amounts can be loaded at a time.)

If we consider the most conservative value of 400 pounds of material being placed in it, here are two common possibilities that can happen.

Both of these scenarios are describing the performance of the SMALL version of the device, the HG 3ab, described below. They tend to require a good deal of time and effort regarding loading material. Long ago, people used to load coal in a furnace to heat their homes, and it turns out that roughly the same total amount of weight of organic material needs to be loaded here as was done then.

We note that there were companies and individuals who were available (for payment) to load the coal in those furnaces so the homeowner did not have any inconvenience, and that seems possible again with this HG 3ab device. We think that hundreds of thousands of lawn-care businesses might be ideal for this function! In the Summer, they mow and collect and then have to dispose of many tons of cut grass and of leaves in the Autumn. If instead of disposing of them, they were spread out and dried like farmers do for hay, they might have a simple and easy supply for very large amounts of the needed materials, which could also be baled up as hay is. Then, in the Winter, when they currently have nothing to do, they could contract to visit homes with HG 3ab devices every few days to load and maintain them. Consider the possibility that such a local lawn-care company would contract to do this maintenance for a winter for say $500. The homeowner would love that, only paying $500 rather than maybe $2,000 to heat his/her house. The lawn-care company would now have something for employees to do in winter, and it would also be nicely profitable! One employee should be able to service four houses per hour or around 32 per day. On average (due to the weather) servicing the HG 3ab about every five days seems to work fine. That means one employee should be able to service around 150 houses, each for $500 or $75,000 income that lawn-care company otherwise never would have! And the employees would have continuous jobs and not just seasonal! Everyone can win!

It is certainly possible to make larger scale versions of this (which will then no longer fit through a standard doorway). One that is twice the dimensions could hold eight times as much material, or around 3200 pounds. Still at a decomposition rate of 5 pounds per hour (during January or February in a northern climate), that is full heat for about 640 hours or about 27 days of whole house heating before a new load of organic material needs to be loaded in it. Keep in mind that the building floor structure would then have to be able to support roughly the weight of a car, and the ceiling would need to be around 12 feet high for that particular size and shape! But the same diameter as a standard HG 3ab could be made but twice as thick, etc, to increase the capacity. There are some structural considerations when such changes are made, such as stiffeners, which may be needed.

This HG 3ab design can also have the built-in capability of providing large amounts of domestic hot water. The arrangement described below can contain either 8 gallons or 14 gallons (of around 150°F water), which can fully heat up from a standard municipal cold water supply in roughly 15 minutes, which can therefore provide a virtually endless supply of hot water for bathtubs or clothes washing. (A full bathtub of wonderfully hot water at fifteen minute intervals for all the kids you have!) (Or all the hot water needed for full loads of a clothes washing machine every fifteen minutes.) The water heating performance of the configuration described below is around 24,000 Btu/hr to 27,000 Btu/hr, reasonably comparable with conventional hot water heaters (which are often rated somewhat higher at the INPUT amount of natural gas consumed). It can easily be increased or decreased depending on the size of your family.

Cooking inside an HG 3ab seems to be an interesting ability, although the internal flailing pipe arms need to be avoided! The cooking action resembles a Crockpot or Slow-Cooker regarding the wonderful taste of the results, but also the time required. This cooking capability requires a modification of the device's door structure, but it nicely cooks hamburgers and many other foods, although the 150°F available temperature requires longer cooking times than on a stovetop. For example, hard-boiled eggs needs about nine hours to be fully done, but they seem to me to be even tastier than normal HB eggs, more delicate, possibly due to not needing the boiling water. In my opinion, cooked sweet corn (45 to 60 minutes) is more tender and delicious than when cooked in other ways. When the corn is cooked while still in the husk, it probably maintains all the natural vitamins as well, which get lost in standard cooking methods. The same seems to be true of other vegetables, possibly because I do not use water for any of those functions. It also does seem to virtually not matter how long the eggs, corn, vegetables or hamburgers are left in the cooker, as even after 12 hours my experiments have all been delicious! This method of cooking is absolutely safe, possibly even more so than conventional cooking, as ALL dangerous pathogens are easily killed at these temperatures, as long as the food rises to above 125°F. With conventional cooking, sometimes the center of a thick piece of meat does not get up above that necessary 125°F, where people can then still have E. coli and other pathogens still present in the meat. That is not possible here. However, "Rare" may not be a possibility, as the low heat for a long time penetrates completely through even thick items of food.

I have discovered that it also can brew amazingly tasty coffee and tea, similar to how "sun tea" is made that is so tasty! But where sun tea is generally rather weak, this system brews tea or coffee that is of conventional strength of taste. There is no harshness in the taste, really amazing.

(Sorry about these tangential comments from the heating system, but new and different uses seem to keep appearing for it!)

(As a side note, many house furnaces are rated at 125,000 Btu/hr or so. That is actually INPUT energy rating, the amount of natural gas burned, for example, where some of the created heat goes up the chimney, leaving a maximum of around 100,000 Btu/hr of actual heat which could be available for the house. Conventional furnaces are designed so that their burner should be on 2/3 of the time when the outdoor temperature is the Design Temperature for that climate [ which is -10°F or -23°C for the Chicago area ]. This means that that 125,000 Btu/hour (input) conventional furnace really is intended to provide a MAXIMUM of around 67,000 Btu/hr of constant heat supply on the coldest night of the year. Generally, calculations for a well-insulated house near Chicago shows that the design heat loss is around 40,000 to 50,000 Btu/hr AVERAGE on that coldest day. This is why we are discussing heat productions of 45,000 Btu/hr as being sufficient and 90,000 Btu/hr as being too much heat!)

This 3ab Version appears to have some major advantages. Instead of the entire drum "tumbling" every hour or so, as occurs in the HG 3a, this HG 3ab body does not move at all!. But there is a central (internal) axle which is spun by a standard fractional-horsepower motor, which has four (hidden) flailing arms sticking out from it inside the chamber. The action is very much like how a farmer's flail type manure spreader works (but slower). The rotating arms inside the chamber act to stir up all the material now inside the chamber. This ensures that each particle of organic material in the chamber gets pushed through a water puddle at the bottom of the chamber, while also being broken apart from any clumps of material that might have become formed. The fact that all the material is constantly stirred around like that also means that each particle has plenty of time in the air inside the chamber. The bacteria's needs are completely taken care of! All in all, it seems a lot like if you watched as a kid how clothes tumble around inside a clothes dryer!

The decomposing material inside might try to "clump up" as some types of materials can tend to do over the time of the decomposition, but the flailing arms quickly break any such clumps apart. Even the supply (puddle) of several gallons of excess water that we keep in the bottom of the chamber tends to get stirred together with all the material, ensuring that all material has sufficient moisture available for good decomposition, again enhancing performance. Plenty of oxygen and plenty of water available to each tiny thermophilic bacterium! They love it! As a result, they decompose virtually anything that is organic very quickly. (Some types of material take longer, such as used car tires or used motor oil or most types of plastic or thick pieces of wood.) Another advantage is that the flail rotation might be slowed to once per day instead of nearly continuously, which degrades the performance somewhat for lower heat production, by nicely slowing down the rate of consumption of the material when less heat is needed for the house. (Slower decomposing material, such as straw, can also be used to cause less heat production.) (I personally do not like a once-a-day rotation rate because some types of material then seem to have time enough to clump all together like coat-hangers in a closet do. Once-an-hour rotation of the flails seems to eliminate this complication for nearly all materials.)

This (small) Version of the HeatGreen home heating system is capable of producing all the heat you could want, but it also can consume the organic materials you put into it very rapidly, but only because its capacity is fairly small! That means that this small system CAN provide all the heat necessary to entirely heat a moderate-sized house in the worst of the winter, BUT for only two or three days before it would need to again be filled with another 400 pounds of material! (400 pounds of material which decomposes each give off around 9,000 Btus of heat in the process, or a total of about 3.6 million Btus of heat generated. If your house requires 40,000 Btu/hr at sub-zero February temperatures, that is 960,000 Btu per that 24 hours, in other words, really nice house heating but only for around three or four days before the HG 3ab needs to be re-filled with material.) This is somewhat labor-intensive, and so we also mention the larger-scale HG 2 Version of this HeatGreen system.

You will build a device that resembles a large exercise wheel for a hamster. Or for a Galapagos Tortoise, as it is bigger. But the HG 3ab does not actually move or rotate! We will describe one that is about five feet in diameter and two feet thick, such that it can be carried through standard doorways. As noted above, that size has an internal volume of around 40 cubic feet. At a density of the organic material put into it of 10 pounds per cubic foot, that means around 400 pounds of organic material can be present to decompose, which will give off a total of around 3,500,000 Btus of heat energy during that decomposition process. (Some organic materials are more compact than that, such as feed corn, where more weight of material can be put in it at a time.

(These are simple and inexpensive enough to build, requiring only around $200 of materials from a local store, that it could make sense to build two of them for your house. You could schedule loading material in them at different times, so that the initial heat-up time while the process is beginning would not be a problem, as the other one would be fully heating the house then. Also, if your water supply or air supply to one of them was interrupted, or any other problem occurred that caused the bacteria to stop doing their thing, the other one could still be comfortably heating your house.)

A wonderful idea toward enhancing the HG 3ab device

Some people had built an unusual variant of my HG 2 system, and their ideas caused me to be inspired regarding a REALLY good idea for any or all of the HG devices! This might be worth considering! Especially if you should discover that you tend to kill off all your bacteria as you are trying to learn how to use the unit! Whether it is a giant HG 2 device or a much smaller HG 3a or HG 3ab device, this modification is pretty close to earth-shaking! Since most everyone seems to decide to build either HG 3a or HG 3ab units, I will discuss those here regarding what needs to be done.

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 3ab. 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 3ab chamber. Just the tossing of cold material into the unit have been known 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?

Parts Materials

(Prices shown are retail prices in Dec 2007 from a home supply store)

FunctionQuantityItemRetail Cost
Main Structure Sidewalls2 sheets of 3/4" thick GOOD QUALITY CDX plywood, of 5- or 7-plies. $21.44 * 2 = $42.88
Main Structure Perimeter1 sheet of 1/4" thick plywood.$13.88
Side Insulation4 2" thick or 8 1" thick sheets of 4x8' foam building insulation, 2" or 1" thick, either interior (white) or exterior (underground). either $6.49 each for interior 1" or $12.29 for exterior 1" each. I spent $47.92
Perimeter Insulation4sheets of 4x8' foam building insulation, 1" thick, interior (white) $6.49 each or $25.96
Attach foamseveral tubes foam adhesive (like PL300).$3.99 each or $11.97
Screwsseveral boxes#10 by 1.5" woodscrews. $2.24 each per 25 or $6.72
Waterproof barrier1a reinforced plastic tarp, around 16 by 20 feet or larger$14.98
Interior structure and water holder1 100-foot roll of 1.25" or 1.5" (black) polyethylene water line (BLUE label is for potable water) 1.25" is $32.48
Fittings for that pipemiscadaptors, clamps, tees.
Air pathmisc4" PVC elbows and pipe.
Axles21" iron pipe sections at least 6" to 10" long..
Air path2standard flexible dryer vent hoses..
Support Rollers4Pneumatic tires from a hand truck or wheelbarrow.
miscmiscmiscellaneous pipe adaptors and hardware..

This should total around $200 of materials.

Note: These instructions are for a unit that is made of very commonly available materials, which are of rather low cost. We have also designed this to be buildable by anyone who has moderate skills as a handyman. There are ways to build many variants of this unit. One example is to line the entire inside with fiberglass instead of the tarp we suggest here. Since most modern tarpaulins are actually made of petroleum-based materials, it might be that over a period of years, the bacteria might slowly decompose the tarp. Since a layer of fiberglass is actually primarily made of silicon / glass materials, that should last for many, many years, but the cost and effort would be much higher initially.

If weight is not considered an issue, it would even be possible to build this out of Corten steel, which is resistant to nearly all types of degradation.

I give permission for any person or company to build as many as 20 of these units without further permission. Beyond that number, I do NOT give authorization without a written (paper) authorization. Specifically, I do NOT give permission to any company to mass produce my invention, made out of any material, such as out of a material such as PVC, without my approval.


On a sheet of the thick plywood, make a mark 34.25" from one end and 13.75" from a long side (or 34.25" from the opposite long side). This will become the location of the chamber centerline, so you can now drill a small hole there. Using that location and a 34.25" long stick or string, draw a circle around that point. The circle should just touch the opposite edge of the plywood as well as the end of the sheet. Using a sabre saw, carefully cut out that piece. data2
It represents most of one side of the structure, and should be 68.5" in total diameter with a D-shaped piece missing.

Place this piece on top of the remaining piece of the plywood sheet, and trace out the edge, where the curve passes through a point that is 16.5" from the (opposite) end of the sheet. When this D-shaped piece is cut out, it is the remaining part of the full circle. These dimensions were chosen such that the full circle of the full side can be made from a single sheet of plywood.

Do the same for the other sheet to get the opposite side of the structure.

You should refer to the construction instructions for the HG3a unit for some details. Specifically, the "1-inch pipe flanges" at the center of both side circles. I still install them in the HG3ab, even though they are not actually used. I used them as REALLY CHEAP shaft bearings for the pipe assembly shown in the photo to the right. Most of the components shown are 3/4" pipe nipples and fittings, for stiffness, but at both ends of that assembly, there are PIPE REDUCERS that drop down to using 1/2" pipe for a few inches. Here is why. The 1/2" pipe section goes THROUGH the short nipple of 3/2" pipe which is screwed into the pipe flange. You might also notice that I slipped an electric box cover over each 1/2" pipe nipple. This assembly is nearly impossible to see inside the chamber, but the electric box cover keeps the 1/2 to 3/2 reducing coupling from wearing against the inside surface of the chamber, essentially keeping the spinning assembly CENTERED in the chamber.

Notice that on the BACK END of that assembly, there is a 1/2" pipe flange, which will later have a large plywood 'pulley' bolted to it such that a fractional-horsepower motor can slowly spin that assembly (which is INSIDE the chamber). The assembly photo shows several 3/4" pipe TEES and even one CROSS. These allow lengths of 3/4" pipe to be screwed into each branch, which creates the 'arms' or 'flails' which spin inside the chamber to stir up the material and to break up any clumps that form. THIS assembly has SHORT arms! Once the assembly is installed inside the chamber, I screw on an additional 12" pipe nipple and coupling on each arm, to make them longer. I want them to reach far enough DOWN to dig through any clumps that might form near the bottom of the chamber.

You also should see that the PVC air path connections and the polyethylene water connections do NOT need any rotating connections like the HG 3a needs! Standard pipe connections are fine.

Next, the sheets of side foam insulation can be marked out and cut very much like the plywood sheets were, again with the desired radius being 34.25". Foam adhesive works great in mounting them. The foam is added as two separate 2" layers, or four separate 1" layers, to have a final insulation rating of R-20. These side insulation slabs extend 4" all the way to the edge of the circular plywood body sides, and that the later sheets of the 1" layers of (white) foam for the circumference can be cut down the middle to get strips of 24" by 96". They will (later) fit BETWEEN the two plywood sidewalls. THAT foam MUST be the 1" thick size, and the interior type, so it can be bent enough to follow the curvature of the perimeter. If you work in a warm area, the white circumference foam should be able to bend to follow the curvature. (Exterior foam is higher density and therefore more rigid and brittle, and would break). Again, four layers of the foam around the edges provides the desired R-20 insulation.

At this point, only the foam for the one side can be mounted, with the rest of the insulation being attached later. But even it can be left for later to avoid it being damaged during construction. All the foam can actually be added once the device is supported on its pedestal stand, where it can be rotated to ease addition of the foam pieces.

None of this foam is ever likely to be exposed to moisture, so white is fine, where the outdoor or underground type is required for wet locations. You could always get another poly tarp and surround the whole device, for example if it could ever be rained on.

Cut the thin plywood sheet (crossways, so that it can be bent easiest) into four pieces which are now each 24" by 48". They will be the "rim" which surrounds the two side circles to form the main body of the device.

You need to also use some of the scrap 3/4" plywood pieces to make Keepers for these pieces. They will have an INSIDE radius of 30.25" with the outside edge being somewhat optional. These small pieces of scrap 3/4" plywood have only one purpose, to follow an accurate circle on the INNER wall of each of the large sidewalls, with that circle being marked at a radius of 30.25". The point is that the thin plywood pieces can then be placed INSIDE that curved shape and using adhesive and wood screws, screwed OUTWARD into the curved scrap pieces.

The thin plywood can be bent enough to follow that gentle curvature of the circle edges. The strips of the thin plywood are therefore screwed to the INSIDE edge of the (scrap) plywood circle, with two of the four pieces straddling the joint with the D-shaped piece for greatest strength and durability. For reasons that will be clear shortly, it is actually easiest if you ONLY screw the thin plywood pieces to ONE of the two circles at this time. This results in the thin plywood trying to flare out. A simple way to deal with this is with a 20-foot long piece of rope, which is temporarily tied around the loose edges of those thin plywood pieces to resemble the circle that they will eventually be. A tow-rope or a load-binder could also be used.

Note that the joints between those four pieces are carefully arranged to not be at the same location where the joints between the two parts of the circle are, for greater structural strength.

You now have a 68.5" diameter disk with a 60.5" diameter, two-foot-high circular barrier upon it.

Place the tarp inside that pit, relatively centered. It actually is slightly off center, such that all the edges of it can reach the opening you will later make in the second circular unit to feed material into the device. That makes sure that the tarp has no edges or seams or overlaps inside the chamber which might someday become less than water-tight. data9
Get the coil of poly pipe. We show the pipe as it is bought, along with some of the hose clamps which will be used with it.

We note here an unusual aspect of this usage of black polyethylene pipe. That material is generally heated to at least 270°F in heat-forming it into various shapes. Because of this, the maximum recommended temperature for black poly objects is therefore usually set at 180°F. However, a Safety Factor of around five is applied in the official guidelines when black poly pipe carries pressurized water, and that maximum recommended temperature is often set at 120°F. The Safety Factor is applied so that there is no chance that an exposed heated pipe might burst and spurt scalding hot water out that might hurt people. In this particular application, the entire 100-foot length of the poly pipe is enclosed inside the decomposition chamber, so that danger could not occur. In addition, such black poly pipe is commonly used as agricultural irrigation piping, where on a hot summer afternoon in a hot climate, the ambient temperature can near 150°F (just like football fields and auto racetracks are sometimes at such temperatures.) We have found no problems whatever in using the black poly pipe inside our chambers, although the clamps can need to be screwed a little tighter after the poly conforms more to the shape of the barb-fitting elbows.

What you are going to do is follow the natural curved shape of that poly pipe (because it is bought in a coil). You are going to use two standard hose clamps, but not in the traditional way. You will use a short piece of metal barstock, between the first two turns of coil of the pipe, to clamp each of the two clamps to which makes a poly pipe circle of a very specific and very sturdy diameter. You will slightly increase the diameter of this first loop, up to where the OUTSIDE diameter is slightly over 60.5". The two clamps are on the two turns of the coil, with the end one about a foot or two from the very end of the poly pipe, but the two clamps are linked together to establish this sturdy diameter. When they are tightened, they will fix that outside diameter of that ring of poly pipe to slightly greater than the diameter dimension you choose. That diameter is chosen so that the coil will be a very tight fit, virtually a press-fit, inside the chamber. When it is pressed down into the corner of the chamber, it will securely hold the tarp in the corner there. Roughly one foot of the pipe extends beyond where the clamp is, so that an (elbow) water connection can be made, which will then extend so both ends of that 100-foot long pipe will extend to outside the chamber.

It is very important to make sure that no sharp corners of any metal could ever rub against and tear the tarp. Wrapping a layer of non-biodegradable duct-like tape is a reasonable way of protecting the tarp surface from all the clamps, especially the extended ends.

That coil of filled poly water pipe can be for a number of different functions. In the Applications Sections below, there are systems that use a SEPARATE (enclosed) supply of low pressure water to CIRCULATE heat to rooms of the house using standard Hydronic pumps and radiators. Similar SEPARATE water systems could heat a swimming pool or hot tub. If the coil is to be used to provide Domestic hot water for the house faucets, it will be filled with water at the prevailing water pressure of the Municipal or well water supply. Since it is not possible for the water to ever get warmer than 150°F, it can never have any threat of boiling.

There are also around eight to a dozen extra clamps needed on that first turn of pipe. (the photo shows only the first loop in place, with the rest of the poly pipe still waiting to be spread out to press against the circular walls.) The extra hose clamps will be roughly equally spaced around the circumference of the ring, to be able to clamp upward metal spacer bars securely to the pipe and later also to the identical poly coil which will be made for the opposite corner of the chamber. The spacer bars can be either 1/8 by 3/8 flatbar strips or 5/16 or 3/8 diameter round rod. For the standard size of chamber described here, 24 inch long pieces of that rod or bar are fine. Around 2.5 inches from each end, a right angle bend is made, with the result being a sturdy spacer bar which will keep the two outermost coils of poly pipe at 19.25 inches apart. (The curved plywood perimeter is 24 inches, minus two pieces of side plywood and the two diameters of poly pipe, leaving very close to 19.25 inch separation needed).

Notice that the detail of the narrow photo here shows that I put a twist in the flatbar stock, which allows the barstock to fit more closely along the sidewalls, which allows the poly pipe to fit better.

The radius of the first and last loop keeps the pipe pressed against the outer (circular) wall and the spacer bars keep the pipe circles pressed firmly against the sidewalls. The rest of the pipe, around five turns, is reasonably snugly pressed against the outer wall. A few additional standard stainless steel hose clamps are used to clamp the intermediate loops to a FEW of the spacer bars, to keep them spaced apart across the width of the chamber, roughly with 3" spacing between each loop.

I am also experimenting with other methods of affixing the poly pipe to the spacer bars. The cheapest and simplest is to use electrical Cable Ties, (shown as the attachment type in the next photo here, to attach to the middle spacer bar shown, but nearly invisible because they are black) but I have doubts whether they will be able to stay tight over the years due to the heat and the motion. I suspect that when I check them in a few years, they may be loose! I am also experimenting with using 16 inch long pieces of scrap SOLID house wiring, wrapped DOUBLE around the pipe and spacer bar (shown in the rightmost portion of the next photo, again with black insulation on the wires so they are hard to see). They figure to be durable, but again the motion over several years may loosen them. But they are much less expensive than the hose clamps which are clearly the best. So I am just using the standard stainless hose clamps on just the two opposite spacer bars, one being shown near the left side in that next photo) which should ensure that the poly pipe will never be able to go very far anywhere. The Cable Ties and pieces of wire are therefore not critical in the operation, and I consider them somewhat optional. If it turns out that Cable Ties will still be fairly tight after several years, that may be the future way to go.

This photo has all the turns of poly pipe securely attached. Notice that the actual spacing of the poly pipe is not critical, and I have some variation in the demo setup.

One of the main functions of this poly pipe is therefore to press the tarp against the circular corner, without needing any kind of adhesive. A second function CAN BE to contain water which will get heated. If 1.25" poly is used, the full hundred feet of it will hold and heat up around 8 gallons of water at a time. If 1.5" poly is used, 14 gallons. If 2" poly is used, around 24 gallons. If 3" poly can be found at a tolerable price, it would hold around 50 gallons of water at a time. Four-inch poly exists, but it is sold in straight sections rather than in a coil, which makes its use a little more difficult, although that would contain even more water at a time. For really big water capacities, rigid PVC 4 inch pipe is probably best and easiest. We find the 8 or 14 gallon to be sufficient, since new water coming in gets heated quite quickly due to all the tube surface area exposed to the 150°F environment inside the chamber. Even 8 gallons of 150°F water mixes with about 14 gallons of 55°F tap water to easily fill a bathtub with 22 gallons of wonderful 90°F bath water! Showers use less hot water and are even more reliable. Washing many consecutive loads of clothes in the hottest of water might be a reason to consider the larger diameter poly, or multiple coils of it inside the structure.

Below, we will calculate that if all the hot water is removed, it generally only takes about 15 minutes for new cold water to become heated fully to the 150°F, so those hot baths could be repeated all day long, as long as they were at about 15 minute intervals!

The two outer rings of pipe therefore press the tarp into the corners of the chamber, without any adhesive and without any fasteners which might have to penetrate the tarp.

At the very ends of the coil of pipe, standard barbed elbows are attached. (the gray barbed fitting is seen near the very middle of this inner photo, elbowed up which will be extended against the sidewall). One end will be connected to an input water supply (of cold water) and the other will be connected to an output pipe of hot water. This arrangement ensures that ONLY hot water could possibly be provided, that any new cold water has to pass through the entire 100-foot length of the coil of pipe, and be fully heated up, before it could ever get to the output connector.

There are alternate ways of installing and spacing this poly pipe. Keep in mind that its primary function is to press the tarp tightly into the corners of the chamber. Having water inside it is simply a bonus regarding making hot water! By using an entire 100-foot long roll of the poly pipe, there are minimal pipe fittings that could ever later leak. It turns out that the tumbling action of hundreds of pounds of the organic material tends to knock loose any poorly attached spacers or clamps!

The second plywood circle can now be installed, again using construction adhesive and screws. Obviously, all the tarp edges are first pushed into the chamber, as shown in the first photo here. Realize that the tarp has covered up the TOPMOST circle of poly pipe, which will therefore press the tarp nicely into the circular corner there. The tarp edges will later be pulled snug along the inside surface (not visible) so that all the edges of the tarp will extend through the material feeder opening, which is indicated by the lines marked out in the second photo here. This particular unit was made to have a 16" square feed door.

I generally climbed INTO the chamber through the feed opening of this second plywood piece, in order to drill and drive the woodscrews that must go OUTWARD through the thin curved perimeter walls into the 3/4" plywood retaining walls just outside of it. I made sure to take my shoes off and just had socks on, to make sure I did not damage the poly tarp I was standing on! I felt a little claustrophobic in there! If you have put the water pipes inside, the very topmost one is very much in the way while screwing in these woodscrews, but I found that it was possible to push it out of the way to do it. Once you are done inside there, get the tarp up in place and then you can push that top tube back into the top corner of the chamber, which securely keeps everything in place. This makes sure that nothing can later move around inside the chamber.

You can also see in the second photo here where the remaining D-shaped piece of plywood will go. Please ignore the two PVC closet (toilet) floor flanges in the photo because a better way has been found to install the air tubes.

You obviously realize that the tarp edges will be pulled through the opening and secured on the OUTSIDE of the side plywood. This will ensure that there are NO openings anywhere in the tarp surface inside the chamber, where water or water vapor could ever escape and cause unplanned decomposition of the structure itself! As long as you did not puncture the tarp anywhere, it should now essentially be able to hold water, except where the feed door assembly will be attached.

The two PVC closet flanges are now mounted, but they DO require that you penetrate the tarp. So use all the adhesives you need to make sure that they will not leak. Since they are both on the axis of the chamber (one through each side wall there) they are actually well above where any significan water should ever be anyway, so maybe that is not as critical as I think it is! They get mounted FROM THE INSIDE, THROUGH the tarp and then through a hole in the sidewall just large enough for the nose of the flange to pass through. Stainless flat-head BOLTS should be used to mount both closet flanges, with the nuts OUTSIDE.

This photo shows the device with the remaining D-shaped piece of plywood added and then a trapezoidal-shaped hole was cut. This hole for the HG 3ab can be rectangular instead (and this photo is of an HG 3a being made). We made this hole 16" in height, about 7" from the axis shaft line. We made the it a 16" square access opening. The hole allows all the edges of the poly tarp inside to stick through, so there are NO holes or punctures anywhere in the inner tarp surface, which should make it absolutely water-tight and vapor-tight.

The second photo simply shows all the edges of the poly tarp being brought out through that hole, to show how they will all be extended a little way along the outside and then tacked or stapled to the outside, several inches back from the edges of the hole. All those edges will actually simply get later pinched between the plywood sidewall and the overlaying insulation and door frame pieces of wood, which will securely hold it in place.

The first photo here shows the first layer of the one-inch white foam skipping the area where we added the stiffeners.

The second photo here shows the four layers of that foam in place.

The first photo here shows the entire device with the perimeter foam in place (although a small section of the outer layer is not yet in place in this photo).

The front will soon be covered by the side foam, where only the final 16-inch square hole will remain and one large PVC pipe at the axis location (on both sides).

The second photo here shows the perimeter of the unit. This shows the foam left exposed. We do not see any major reason that cannot be left, with a few related thoughts. The white foam is very susceptible to being damaged, so if the device is where it might be bothered by kids or pets, it might make sense to go to the extra trouble of covering it with thin (masonite) paneling or wall paneling or even an external tarp. The one which was assembled for the photos here will have a covering of (artificial) naugahyde, to resemble a piece of furniture. The white foam also disintegrates pretty quickly if it gets wet, so if that is a possibility, then the same should be done. It can also be painted, decorated, to become an active artistic object. If it is in a location in the house, kids' school projects or awards could be attached to it, where they would forever be moving around. It could also become the world's slowest moving Mobile sculpture!

The blue or pink foam is far more resistant to moisture and abrasion, BUT it tends to shatter rather than bend around the curvature, so if you try to use that material, be very careful about that.

The four pieces of wood for the door frame are here. The wood pieces function as many things, including squeezing the overlapped poly tarp edges under the conveyor piece for good airtightness and watertightness. They also provide a strong frame for the door which will later be mounted, as well as a solid structure for the hinge supports and latch for that door.

As just noted, only the very outermost ends of the 4" PVC pipe connections are now visible, regarding the airpath.

The barb elbows of the water connections are also visible just outward of (above in the photo) the larger connections.

The overall final appearance is therefore quite clean looking, with only the access door (not yet shown here) and the four pipe connections visible at all.

Two digital thermometers are also seen here, which are somewhat optional. They cost around $13 each, from any of many sources. Some such thermometers have a design limit of 140°F, which would be a problem. Most can operate to 160°F, which is excellent. These shown happen to operate up to 110°C or 230°F, which is not really necessary. One of these monitors the temperature inside the chamber and the other monitors the temperature of the water in the poly tubing. The two readings are nearly always virtually the same, except when massive hot water usage has occurred, and the recovery rate of the water heating can be then monitored. I find the greatest value of monitoring the chamber temperature to be when any variation occurs. It helps me know what I might want to do, regarding adding more water or turning on the air blower or speeding up or slowing down the tumbling. As long as the device can rotate regularly, and there is plenty of free water in a puddle inside it, and there is plenty of air/oxygen being blown into the chamber, the decomposition process seems to be very reliable. If TOO MUCH airflow is provided, it can operate at a lower temperature. As long as that temp is at least 125°F, that is no problem regarding thermophilic bacteria activity and it can even ensure excellent decomposition efficiency. If thicker pieces of material are used, or there is so much airflow provided, then the chamber operates due to the different mesophilic bacteria, and the chamber temp stays below 125°F, with slower decomposition, which seems desirable during milder weather. However, if the chamber has already been operating at the higher temperatures, and then it drops to the lower temperatures, then thermophilic bacteria can die, and a re-start might be needed in order to again get it up to the higher temperature operation, with some new mesophilic bacteria from a couple handfuls of black dirt. If the temp ever gets ABOVE 150°F, I generally turn the blower on, to make sure thermophilic bacteria do not die from excessive heat. It is currently still unknown just how high a temperature they can survive, so this might eventually be increased to 155°F or 160°F or higher.

This particular HG 3ab unit has an additional thermometer inside it as an experiment. There are REMOTE SENSING thermometers which cost around $25 or so at many big box stores. They do not require wires between the temp sensor and the readout, so the wires seen in the photos may not be required. However, the manufacturers do not give any information regarding how well the remote sensor unit can withstand long periods at fairly high temperatures and very high humidity.

On the opposite side of the unit, NONE of these are visible, and it is a simple smooth flat circle of surface!

The blower gets attached (to our right larger connection) and the other connection could either be left unconnected (which then exhausts high humidity and carbon dioxide and some occasional musty smells into the room area) or a flexible dryer vent hose could send those exhaust materials outdoors or to some other area. The fact that there is a lot of available warmth, a lot of humidity and a lot of carbon dioxide, makes it an ideal source for feeding into a nearby greenhouse, which can greatly increase the growth of fruits and vegetables.

Hinge mounts for the feed door can be securely mounted to the (now invisible) 2x10 pieces of lumber which framed the sides of the door opening. A (here horizontal) rod then becomes the hinge axle for the door being then able to open upward. I find it efficient to use one hand to raise the feed door and the other hand to toss in whatever new material is to go into the chamber. This then does not cause the door to the 150°F chamber to be open for more than a few seconds at a time. If the door is left open for a few minutes, the chamber cools down to below the 125°F that the thermophilic bacteria best thrive in, so it is best to not leave the feed door open for any longer than necessary.

The poly pipe barb fittings can be connected to adaptors to standard hose or iron pipe, conveniently using standard washing machine supply hoses. One attaches to a water supply source (with a check-valve to ensure that hot water is not fed backwards into a cold water supply line) and the other connected to hot water taps or other usage of hot water.

The entire foam insulation surface can be covered by an assortment of materials. Fake naugahyde is of moderate expense and easy to work with, and capable of making many attractive appearances. If this device is to be installed outdoors or in a rough environment, it may be appropriate to cover it all in weatherproof and/or damage resistant material.

The plumbing (and potentially air) connections would be an additional problem if the device was allowed to always rotate in one direction. There ARE special rotary fittings available but they tend to be expensive. Instead, we have designed it where the entire assembly rocks back and forth, ONLY ROTATING ABOUT 3/4 turn and then reversing. All of the material inside still gets to be gravity-tumbled inside, but the plumbing and air path connections become far simpler. The air hoses for air/oxygen in and carbon dioxide out can then be simple standard clothes dryer vent flexible hoses. The water connections can be standard hoses used to connect a washing machine to house piping. They should all last a number of years. Keep in mind that this rotates so slowly that it is hard to even notice, the FASTEST being around once per hour. (A tiny (hobby) electric motor which might be used to rotate the drum might then be DIRECT CURRENT, where simply using a relay to reverse the wires makes the motor turn the other way, so it could oscillate back and forth its 270° of rotation. This limited rotation aspect also permits adding a "cooking chamber" which would never have to cross under the mass of material inside the chamber. -->

You have scraps of pieces of the thicker plywood. An optional feature you might consider is to cut out a number of arc shaped pieces, which have an inner radius of maybe 28" and an outer radius of slightly over 34.5". They would be mounted to either of the side wood circles (by screws and construction adhesive) such that a larger radius of the plywood (of just over 34.5") is present there. The only purpose for this is so the wood could extend beyond the 4" thick of foam insulation which surrounds the entire structure. A tiny motor could then rub against that (circular) edge to very slowly rotate it. The rotation rate only needs to be once per hour, so a very tiny motor would be fine for that. (It CAN be rotated faster if you wish but there is no known advantage in doing so.)

A "trap door" then must be made in one of the sides. It should not be closer than 6" from the circular rim, but can otherwise be of somewhat optional shape and size. It will provide a way for you to reach inside to mount the few last small items, and it will also be the opening through which you will later add organic materials. It obviously should be large enough so both of these tasks are as easy as possible.

The door needs to fit decently tightly, and it needs to have a SEPARABLE provision for its two or four layers of foam insulation attached to it. The outdoor foam can be an advantage for the outermost layer, just to be more abrasion resistant.

The "remaining items" are the water pipe connections and the airflow connections.

We know that we desire a standard decomposition rate of around 5 pounds of material per hour, with a maximum of 10 pounds per hour. From our previous discussions in related web-pages regarding the biochemistry of what is going on, we know that this will create around 45,000 Btu/hr (90,000 Btu/hr) of heat. We also can calculate the amount of air needed and exhaust removed for those decomposition rates. You can confirm this with the equations given in those other pages. We learned that about 12.6 gram-moles of chemical reaction occurs per hour. Our five pounds of glucose combines with about 5.3 pounds of oxygen in the intake air, to form about 7.3 pounds of carbon dioxide and about 3 pounds of water (or water vapor). Air is only around 1/5 oxygen, so we will need to supply around 26 pounds of air per hour, each of which takes up around 13 cubic feet. This means that we need an INFLOW of around 338 cubic feet per hour, or 6 cubic feet per minute (6 CFM). This is a VERY small air flow rate! Because of the Law of Partial Pressures, the outgoing exhaust air cannot be more than around 4.4% carbon dioxide. We know that we need to exhaust about 7.3 pounds of carbon dioxide every hour, so this means that we need to exhaust around 140 pounds of exhaust AIR each hour, which each take up around 14 cubic feet (due to the higher temperature of that exhaust gas). This tells us that we should expect to need to exhaust around 1960 cubic feet per hour of air or 33 CFM. Note that we could supply 6 cfm of air to provide the needed oxygen, but that airflow might not exhaust enough carbon dioxide!

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. When we might reduce the actual airflow, the main effect is that there is 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 double that capability, in case we should ever want it to decompose the maximum 10 pounds per hour, which means we should provide airpath sizes where 66 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.

The (two) 4" diameter holes are made with their centerlines 4" in from the outer edge (in other words, 27" from the axle. We chose to use (toilet) closet floor flanges, to be able to ensure that we can mount them with no moisture or air leaks through the sidewall (due to the fact that we have to penetrate the tarp there). Caulking is used UNDER the flange (and against the tarp) for this reason. Flat-headed bolts are used to mount these closet flanges rather than the usual wood screws, for better strength and durability.

A variant of this is shown in these photos, where the cutout for the door opening (in the plywood sidewall) is made a trapezoidal shape which allows the entire area for the door AND tubes and pipes to NOT have to penetrate the tarp itself (but rather the piece of black conveyor belting shown).

One is mounted near one side of the circle, and the other is mounted on the opposite side of the (same side) circle. One will generally stay near the top (due to the oscillatory motion) and it will provide air/oxygen IN for the device, but ONLY when it is near the top as it rotates. The other will then be near the bottom, where the more dense (heavier) carbon dioxide tends to accumulate. Due to the air/oxygen being pushed into the chamber by the blower, the carbon dioxide will be forced out through that lower hole. Standard 4" PVC elbows and pipe sections (just beyond the 4" thickness of the insulation) gets this connection to be near the axle shaft where the flexible dryer vent hose attaches to it there, to finally connect to 4" PVC pipes which are mounted to the fixed support stand of the system.

If the capability of providing domestic hot water is to be also used, those connections can be handled in similar ways, where the connection uses standard (flexible) clothes washing machine supply hoses for the water connections, also near the axle of the system so that there is minimal actual motion of the flexible hoses. Such hoses usually come with a built-in filter which should be removed for greater water flow rates.

Standard (micro) switches could be installed to stop the device from rotating beyond the desired 270° of rotation and to cause the motor to reverse, so it would then constantly oscillate back and forth. This actually results in one portion of the inside of the chamber never having to pass through the puddle of water that is always kept in the bottom. This is essentially why it can have an openable door in the location shown in the photos, as that door area can never be at the very bottom where there MIGHT be several inches of water in a puddle!

An attractive possibility which I am currently (12/07) experimenting with is where a (sturdy) 6" or 8" diameter thick aluminum pipe is installed across the entire 24" width of the chamber, but which has an end cap and is well grouted to be watertight. I see this as an attractive "cooking chamber" where even hard boiled eggs (without any water!) and hamburgers can be cooked. The cooking is at a slower rate than on a stovetop burner, but the 150°F temperature of the chamber is quickly conducted through the aluminum walls to provide close to a 150°F cooking temperature. That is plenty to kill any dangerous germs (only around 125°F is needed for that), and food seems to cook very evenly, without ever burning the surfaces, in around two to three times as long as on a stovetop! I am looking forward to seeing if spaghetti can be cooked in it!

This (standard-sized) unit has a total diameter of around 5'9" so it can easily be carried (or rolled) through normal doorways. However, the width dimension of what we have described here is essentially 32", so if it has to pass through a standard 32" wide interior doorway, you may need either hold off installing one layer of the side foam or remove the casing trim of the doorway!

This unit has a total surface area of about 72.5 square feet. The insulation that we have described is all R-20. The temperature difference if this unit is placed in the heated portion of a house is around (145°F - 70°F) 75°F. This indicates that the heat loss outward through the insulation is 72.5 * 75 / 20 or 272 Btu/hr. This very minimal loss allows the contents of the chamber to rapidly get up to its operating temperature. (This very low value might indicate that future units might not need quite as much insulation, to still perform well.)

When the chamber contains 400 pounds of organic material and also 200 pounds of water, the thermal capacity is around 350 Btu/degree. That means that it first requires 350 times 75°F or 26,000 Btus of heat to be internally developed to first get up to 150°F. It also means that the interior material can release 350 * 25°F or around 9,000 Btus of energy in dropping the interior temperature the 25°F from 150°F down to 125°F, the general range of operation of the thermophilic bacteria of this device. If the entire amount of 150°F hot water is removed (as for clothes washing or a really hot bath), when the pipe all fills with cold (55°F) water, it briefly uses much of the capability of the system to heat up all that new water up to the 150°F, a process that generally should only take around 15 minutes of the heat to accomplish. The warm air heating capability therefore drops somewhat when large amounts of hot water are withdrawn, but recovery is generally within 15 minutes max.

A variant Regarding the Support and Mounting

This is essentially exactly the same device but with two differences. (1) there are NO axles and mounting pillars at all; and (2) additional plywood is attached to the sidewalls, to create a rigid and very strong plywood ring on both sides of the unit. (This variant is VERY easy to roll around to get it into the desired room in a house, as the plywood rings extend slightly beyond the insulation and are therefore like giant wooden wheels! Which is actually the point. They have an ACCURATE consistent outer diameter, where they can each ride on top of two rollers which are mounted to a base assembly. There is NOTHING actually holding the HG unit in place (except gravity) and it could be lifted off of the rollers if needed. This results in a smoother, cleaner appearance, and there are no obstructions to get tangled with the hoses or vents. With this variant, there is no obvious way to keep the unit from rotating beyond the 270 degrees that is possible with the HG 3ab unit assembled above. Care would be needed to not allow the hoses and vent connections to get all twisted up. This variant may eventually be called the HG 3abb unit.

Getting Heat Out For the House

There are multiple ways to get the usable heat out of this device for a house. They each have different overall efficiencies, complexities, costs, and potential advantages and disadvantages. These different methods use the exact same device described in the construction above. These are presented in no particular order:

Using it, Selection of Organic Materials to Use

The DIMENSIONS of the organic materials are extremely important regarding how QUICKLY the process occurs. THICKNESS is the most important of the dimensions.

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 (with the one exception of really rotten wood as noted below), 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.

I have discovered that in relatively MILD weather (like September or November or March or April in Chicago) it is possible and even attractive to load it primarily with wood chips or similar THICKNESS pieces. Such materials decompose far to slowly for the greater heating needs of January and Februry, but they seem ideal for the milder parts of the winter. They produce and give off much less heat AND they last for a number of weeks! ALL of September seems to require only one loading of such materials! (the black dirt is still necessary to provide the needed bacteria.) October seems likely to require two loadings, of mostly such materials but mixed with some weeds and field grasses and some leaves.

So I now tend to SAVE the cut lawn grass to be used mostly during January and February, when greatest heat output is needed.

I have also discovered another handy thing about that cut lawn grass. I now use a BAGGING MOWER but mow the lawn with the bag REMOVED. The cut grass then lays on the lawn for about three days. It turns yellow as it dries. Then I put the bag on the mower and run it around the yard again! It now sucks up all that dried grass, so I can immediately put it into leaf bags or storage bins until I will want to use it several months later. Otherwise, cut, wet lawn grass seems to quickly go into its own mode of natural decomposition, where it then heats up in the storage container and starts consuming itself!

Finally, it appears that each square inch of surface area of ANYTHING I put in the HG 3ab is able to produce roughly ONE-FOURTH Btu/hour. When I have used wood chips that are around 50 pieces per pound, when I have put 400 pounds of them in the HG 3ab device, that would be around 20,000 separate pieces. If each has a total surface area of one square inch, that would total about 20,000 square inches. At 1/4 Btu/hr/square inch, that comes out to about 5,000 Btu/hr total heat production for the unit, which seems about in line with the performance I have seen in this low-output mode of operation. (the 3.6 million Btus of chemical energy in those 400 pounds of such wood chips would then last for around 720 hours or 30 days at that rate!)

That is an excellent situation during MILD weather when little heating is needed for the house!

A pound of cut grass seems to usually contain maybe 3,000 blades of grass. If each are 2 inches long and 1/8 inch wide, the total area of each grass blade (both sides) would be about 1/2 square inch. At 3,000 blades per pound, 400 pounds of such grass would contain about 1,200,000 blades or around 600,000 square inches total area. At 1/4 Btu/hr/square inch, this arrangement could produce around 150,000 Btu/hr total output. (the 3.6 million Btus of chemical energy in those 400 pounds of cut grass would then last for around 24 hours at that rate!)

That is a little more than I have yet obtained, but I have never put in a full load of just cut lawn grass! But when MOSTLY using cut lawn grass, I have obtained the 90,000 Btu/hr mentioned in these pages.

You might see that thick pieces of firewood have such small total surface area that little heat gets produced. Consider a standard piece of 6 inch diameter firewood which is two feet long. The total surface area is about 500 square inches. Using the numbers above, this would imply that only around 125 Btu/hr of heat would be generated. Such a piece weighs about 14 pounds, so it would contain around 121,000 Btus of chemical energy in it. That piece of firewood WOULD gradually decompose in the HG 3ab unit, but it would likely take about 121,000/125 or 1,000 hours! That is close to two months! So it WOULD work, but the heat output is so extremely low (130 Btu/hr) that it does not seem very desirable.

Yes, a really LARGE HG unit that could contain a THOUSAND such pieces of such firewood (14,000 pounds of wood) might produce the heat needed to heat a house. Another possible future application! Or an explanation for why it is much more acceptable to mix in pieces of firewood inside the larger Version 2 or Version 4 systems.

Suggestions regarding people's experiences of putting specific materials into HG 3ab units.

This is ONLY for people who enjoy pain! Here is the THEORETICAL explanation regarding the heat radiation that is created by each blade of grass or leaf inside the unit!

There is a relationship that has long been known in science and Engineering called the Stefan-Boltzmann Law. It calculates the amount of radiative energy produced by any hot object inside a cooler environment. It is fairly simple in its crudest form:

Q = σ * (T14 - T24) * A

The temperatures are the temperature of the object doing the radiating (1) and the temperature of the surrounding surfaces (2). A is the surface area of the object doing the radiating. And the sigma σ symbol is a constant, called the Stefan-Boltzmann constant, which is 0.1713 * 10-8 Btu/square foot/hour/((absolute degrees R)4)

When wood is burned in a woodstove, the flame temperature is around 2300°F or 2760°R. These calculations show that a square foot of burning wood (actually in flame) creates around 100,000 Btu/hr of radiant (mostly infrared) heat. A woodstove generally only has 1/8 to 1/3 square foot actually on fire at any instant, so it creates the output that woodstoves are known to generate!

OUR situation is at a far lower temperature! We only create heat of around 1/3000 as much (per square foot). If we assume that the actual temperature at the bacterium is 160°F and the actual temperature of all the walls are 140°F, we can use the Stefan-Boltzmann Law to calculate that each square FOOT of material should be creating radiation of about 32 Btu/hour. Therefore, each square INCH would be creating 32/144 or 0.22 Btu/hour. This is in pretty good agreement with my experimental findings of 0.25 Btu/hour from the material in my HG 3ab units.

We also need to note that when we use ALL chunks of larger material, we are INTENTIONALLY not creating as much heat output, but this also results on the temperatures being lower. If we use mostly straw and field grasses and weeds, we might assume that the actual temperature at the bacterium under such conditions is 140°F and the actual temperature of all the walls are 120°F, we can use the Stefan-Boltzmann Law to calculate that each square FOOT of material should be creating radiation of about 29 Btu/hour. Therefore, each square INCH would be creating 29/144 or 0.20 Btu/hour.

If we use mostly wood chips, we assume that the actual temperature at the bacterium under such conditions is 120°F and the actual temperature of all the walls are 100°F, we can use the Stefan-Boltzmann Law to calculate that each square FOOT of material should be creating radiation of about 25 Btu/hour. Therefore, each square INCH would be creating 25/144 or 0.18 Btu/hour.

In case you were interested, you now know WHY the various organic materials you can put into an HG 3ab unit generate different amounts of heat output. The greatest factor is the total surface area which can interact with oxygen and therefore create and radiate heat away, but even the overall temperature of the activity has additional effects!

This also explained why a woodstove only needs to have a FRACTION of a square foot of wood actually on fire at any instant, and we need to have a LOT of square feet of surface area decomposing, to produce similar amounts of heat output.

There is a way to estimate the amount of water you should put in when you start this unit up. If we are considering around 400 pounds of organic matter inside the chamber, we will consider the two extreme situations:

IF the grass, weeds, or leaves are fresh, essentially still alive, then they already contain within them a large amount of water. In this case, very little additional water needs to be added at the start. I add around five gallons so that there is a decent sized puddle in the bottom of the chamber. Then, as the device rotates, all of the organic material has a chance to get wet from passing through this puddle.

If the grass, leaves, straw, or hay is fully dried (for better storage), then a large amount of water needs to be added FOR FULL SPEED OPERATION. We know that the glucose weighs about 180 pounds per pound-mole, and the water weighs around 18, but there are six waters necessary for the reaction so they total 108 pounds. Using this proportion, if we start with 400 pounds of FULLY DRIED material, we would need to add around 240 pounds of water! That is around 30 gallons!

So you need to judge how damp or dry the material is when you first start the unit, to estimate the amount of water you need to add. However, that amount of water is for MAXIMUM performance! By providing LESS water than that to dried materials, the decomposition can be substantially slowed down, which is wonderful for milder weather!

Once it is in operation, you should only need to add extra water due to two conditions: (1) the air exhausted from the unit carries a substantial amount of moisture/humidity in it. This amount of moisture loss depends on the actual temperature of the air exiting the unit, as that air is essentially always at 100% humidity. But it can be fairly substantial, and you are likely to need to add extra water on a regular basis. (2) if you add in materials such as dried leaves or dried hay, you will need to also add the appropriate amount of water.

Except for the moisture that leaves in the vent pipe, we note (from above) that the decomposition of 400 pounds of organic material will PRODUCE about 240 pounds of water, and so it tends to provide its own supply of water to a great extent.

Storing the Organic Materials

If you are able to mow the lawn all year, you may not need to store amounts of the material to decompose for a winter. But most of us live in climates where we need to plan ahead.

It is impossible to store most organic very long if they are not dried out, as the decomposition process will occur naturally in the presence of moisture, resulting in rotting and decay (and foul smells due to anaerobic processes occurring). Therefore, if you need to store materials for more than a week or two, you need to dry it out. Farmers have long had appropriate processes, in drying hay and straw before baling it up to be able to last many months. Also in drying feed corn for storage in grain silos. Even in leaving corncobs and crop debris out in the fields so that the sun can dry it all out naturally. Essentially the same processes can be used to dry cut grass and leaves in order to bale them up for later use.

Such bales then obviously need to be stored in a dry location. When they get damp, they start to rot and decay. THAT can sometimes cause an unexpected hazard in large stacks of hay bales! If one of the bales got wet, the decomposition process can begin, which creates the heat we have been discussing. There have been cases where large stacks of hay bales have spontaneously caught fire due to such internally generated heat. Therefore, really large stacks of hay bales should be avoided.

Similarly, great care needs to be taken regarding WHERE these bales are stored! If a single person wanders by and tosses a cigarette butt onto the stack of bales, a very serious problem can quickly develop. So you need to find a location where such a danger either cannot occur or if it does, it would not affect too much else. Farmers generally store hay bales in a building separate from where they keep valuable animals or equipment for this reason.

The storage of so much material that has been very well dried, and which is therefore extremely combustible, is a matter that requires great attention to ensure safety.

There seem to be endless new uses for this critter! Here are several more that I have started to experiment on!

I find the need to add two personal comments here!

(1) People seem to INSIST on "improving" anything and everything with their own ideas! It does not seem to matter whether they actually have any education, knowledge or experience in the specific subjects or talents or abilities! An example has come to my attention, which will probably be repeated countless thousands of times in the future. A woman, with NO construction experience whatever, and no education or background in either Engineering or Design, decided to "make changes" in the above instructions, and intended to also improvise in the actual construction due to her lack of tools and experience. She decided to change the dimensions of the device, change the construction of it in dozens of ways, such as using two layers of thin used plywood for the sidewalls, and in using very small diameter pex tubing instead of the far larger poly tubing that is specified here. In addition, she did not like the limitations of how it is described to be used, and improvized her own ideas on how and where she would install it, such as building an insulated room inside her garage, and then doing incomprehensible things to pipes and ducts to provide heat for rooms and functions throughout her house. As near as I can tell, she is NOT using even a single one of the above directions as it is described, modifying or entirely dismissing every single one of them! What was the point of even providing construction instructions if they will be absolutely ignored? Will I expected to be responsible when such an extremely modified attempt will only partially do what is described here?

I realize that people throw away the instructions for the Christmas bicycle they need to try to assemble for their child; it seems to be part of human nature. That's fine, as long as I do not get blamed for the results of such "improvements"!

Here's another 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 3ab will work like a charm. However, if you greatly alter even ONE 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 spend 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 HG3ab 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 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!

In order that you not waste $200 on building materials from a local store!

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 the 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!

The main presentation was first placed on the Internet in February 2007. This high-performance version presentation was first placed on the Internet in November 2007.

Energy-Related presentations in this Domain:

Self-Sufficiency - Many Suggestions A thorough presentation
Global Warming - The Physics of the Process. (June 2004, June 2008)
Global Warming and Climate Change - The Physics (June 2004, Feb. 2007)
Alternative GREEN Water Heater - Non-Fossil-Fueled HeatGreen - A Simple Water Heater, HG3a (biodecomposition) (March 2007)
Alternative GREEN Furnace with no Fire - Non-Fossil-Fueled HeatGreen - A Simple, Home Heating Furnace, HG3a (biodecomposition) (March 2007)
Solar Heating - Low-Tech Active System Low-tech, low cost approach (April 2007)
Heat and Cool a House Naturally, without a Furnace or Air Conditioner (1977, Nov. 2000)
Energy Supplies of the World - Petroleum, Coal, Gas, Uranium. Oil, Natural Gas, Uranium supplies and consumption (May 2010 Report)
Asphalt Pavement - Black Surfaces and Sunlight Environmental Effects of Asphalt Pavements, Roofs, and Parking Lots (August 2007)
Earth Spinning Energy - Perfect Energy Source From the Earth's Spinning (1990, Nov. 2002)
Earth's Spinning - Perfect Energy Source (1990, Dec. 2009)
Tornadoes - The Physics of How They Operate. Tornadoes, including How they Form. A potential energy source (Feb. 2000, May 2009)
Electricity - Unlimited Source of Solar by an Artificial Tornado. Tornadoes, including How they Form. A potential energy source (Feb. 2000, May 2009)
Survival Ark - 60-Acre Hexagonal Artificial Island, Floating Communities for Survival For Sealevel Rising (July 2008)
Electric Power Plants - Climate Effects
Global Warming Effects of Carbon Dioxide
Hydrogen as a Fuel for Vehicles. (August 2003)
Solar Heated House NorthWarm Totally 100% Solar Heated House - Version 1 (1979)
Solar Cells Photovoltaic Cells, PV, Electricity from Sunlight (Jan 2002)
200 mph, Safe, Self-Driving Cars, Trucks, Economical 200 mile per hour TRANS Super-Efficient Transportation System (invented in 1989)
Electric Cars, Hybrid Cars, the Physics Battery-Powered, Hybrid Cars and Hydrogen-Powered Vehicles (April 2006)
Wind Power, Wind Energy, Practical Windmills Practical Wind-Generated Electricity (Residential, some Watts) (1975 and April 1998)
Tower Windmills and Electricity, Modest Efficiency Practical Large-Scale Wind-Generated Electricity, 1200 KiloWatts (Community, a thousand homes) (a million construction jobs and 12,000 MegaWatts of electricity Nationally) (June 2007)
Earth Energy Flow Rates due to Precessional Effects (63,000 MegaWatts of Energy) (Sept 2006)
Power Plant Wastes - Productive Usage of Nuclear Waste. Productive Disposal of Nuclear Power Plant Wastes (1980s, Sept 2005)
Conserving Energy - Methods and Processes
Energy Storage - Methods - Efficiencies Various Methods
Solar Energy - How Much Energy Comes From the Sun
Sun and Stars - How the Sun Works - Nuclear Fusion. Creating Light and Heat
Energy Inventions - Many Forms of Energy Supplies. Related to Energy Crises
Solar Energy - Generating Electricity From solar, wind or other sources nearly 24 Hours a Day (2001, tested 2003)
Solar Energy - Generating Electricity, Improved A Unique Method of Using Solar Energy to Generate Electricity (late 2010)
Alaska Pipeline - Alyeska - Physics. Pipeline Local Climate Effects (August 2005)
Home Air Conditioning Natural, GREEN and FREE! (1978, December 2000)
Hybrid Vehicle - An Improvement. An Entirely Different Approach to a Hybrid Vehicle (1992, May 2008)
Woodburning Furnace - JUCA Fireplace, Woodstove - JUCA Super-Fireplaces (designed 1972, manufactured 1973 on, still not matched)
Burning Wood for Heating - The Physics. Wood as a Heating Fuel (published 1978)
North Pole is Heating Very Fast. Faster than anywhere else on Earth.
Global Warming and Climate - Possible Solutions
Aerodynamic Lift - How Airplanes Fly. Bernoulli Effect, Reaction Lift (April 2003)
Efficient Airfoil Flight - Active Surface - TURCAN. Greatly Reducing Turbulence and Drag for Aircraft and Airfoils, TURCAN (summer 1998)
Construction School for GREEN Technologies. My Concept of a GREEN Campus (1990, Dec 2008)
Conservation of Angular Momentum - An Exception or Violation. A Violation of the Conservation of Angular Momentum (Sept 2006)
Hurricanes, the Physics and Analysis A Credible Approach to Hurricane Reduction (Feb 2001)
Automotive Engine - A More Efficient Approach. Significant Improvement (2001)
Global Warming - The Politics and Business Why No Leaders Seem to See Urgency in Global Warming
Energy from the Moon - A Version of Tidal Energy Collection. (Artificial Tides) (1998, 2010)
Energy from the Moon - Version of Tidal Energy Collection 2. (Energy Harvesting) (1975, 2010)
Electricity from Solar, Wind, Water, More. Make All Your Own GREEN Electricity (2001, 2003, 2010)
Woodstove Energy Production and Efficiency, from a Radiant Woodstove (published 1979)
Firewood Ratings. Firewood Info Chart.

This page - - - - is at
This subject presentation was last updated on - -

Link to the Public Services Home Page


Link to the Science Projects Index - Public Service


E-mail to: Public4@mb-soft.com

C Johnson, Theoretical Physicist, Physics Degree from Univ of Chicago