Alternative GREEN Water Heater - Non-Fossil-Fueled

HeatGreen - A Simple and Non-Fossil-Fueled Water Heater

For as Little as $100 Total Investment!







If the yard around your house is fairly large, an acre, then a really amazing fact exists which no one seems to have ever noticed before! In a given calendar year, the (9 tons of) fallen autumn leaves, cut grass particles and other dead organic materials which had grown on that acre due to Photosynthesis, will decay. You knew that! What you didn't know is that the process of that NATURAL decay or decomposition gives off heat in the process, an amazing amount, around 170,000,000 Btus or 50 MegaWatt-hours of energy! (If your yard is smaller, 1/4 acre, then around 40,000,000 Btus or 12 MWh of heat energy is released during the year.) This becomes REALLY interesting when you note that you likely pay around $500 to buy natural gas or electricity to heat your domestic hot water during the year, because the water heater loses around 10,000,000 Btus or 3 MWh of heat during the entire year, in heating and maintaining your hot water supply.


There is NO FIRE created so this is far safer than conventional furnaces, which burn fossil-fuels to create 3,800°F (2,100°C) fire just to provide the 150°F (65°C) warm water you enjoy in your house! This system uses NATURAL DECOMPOSITION of decaying lawn materials to easily produce that desired 150°F (65°C) warm water directly! Actually, that heat IS always created during natural decay, but no one has ever collected it for useful purposes. Right now, that heat is being given off, outside your window, over many months and over the large area of your yard, where the average heat given off is only around 1/2 of a Watt per square foot, so no one seems to have even NOTICED the available heat before! Doesn't it makes FAR more sense to simply COLLECT this naturally occurring and immediately available heat, which does not COST you anything and which is already sitting there outside your window? AND it does not consume precious earth resources or produce the environmental consequences of burning fossil fuels. It uses absolutely GREEN materials, which are going to decay naturally anyway, to entirely heat your home and hot water!


First placed on the Internet in March 2007 Prototype unit first built March 2007, which then fully heated an entire large house in Chicago winters from 2007-2014






In both cases, the oxygen in the air inside the garbage can gets used up so after a few days, you would need to open the lid to let more air in, to continue the heat production. Otherwise, in both cases, the temperature inside would start to drop, and everything would slow down again. The devices described in these web-pages ensure that the bacteria always has a good supply of warmth, water and oxygen, so you get reliable heating from the device.

Benefits of this HG 3a system include:

  • Never pay for hot water bills ever again!
  • Great for the Environment! Completely GREEN!
  • No burning, no fire, no flame at all!
  • Never use fossil fuels again!
  • Build it yourself for around $200!
  • Step-by-step Instructions provided.
  • The HeatGreen 3a device was designed to entirely heat an entire house in a very cold climate, so it easily can generate the heat for hot water. In fact, providing BOTH heat for a house and also heat for hot water is fairly easy to accomplish.


    Public Service
    Self-Sufficiency - Many Suggestions

    Environmental Subjects

    Scientific Subjects

    Advanced Physics

    Social Subjects

    Religious Subjects

    Public Services Home Page

    Main Menu
    Rotating Five-foot diameter HG 3a showing two digital thermometers, two air ducts and two water pipes, axle shaft, feed door opening, and pink heat insulation (built in May 2007 of $200 new materials). This is a Normal-sized Rotating Five-foot diameter HG 3a showing two digital thermometers (internal air and water), two air ducts and two water pipes, axle shaft, feed door opening, and pink heat insulation. Maximum heat production about 90,000 Btu/hr for about two days at a load. If it is not used for house (air) heating and is exclusively for heating water, it can provide a constant 20,000 Btu/hr to fully heat all the domestic hot water for a family for about ten days or two weeks per loading. (built in May 2007 of $200 new materials).








    Described below is a very practical device that you can make (with the instructions which are included), which will allow you to greatly reduce your contribution to Greenhouse Gases and Global Warming, while also saving you a lot of money, and even being absolutely Green! It can provide you free hot water forever, with no cost and no usage of any fossil fuels, to be absolutely Carbon Neutral.


    Here is a "teaser" for you!





    If you intend to ENTIRELY heat all the year's hot water for a medium-sized home, and it is in a cold northern US climate, more than 100 such (small) bags might be needed! But most or all of that can be collected from YOUR OWN yard, so nothing should have to be bought!


    Is this Biofuel? Is this Biogas?





    The system and the devices we describe CAN be used to produce Methane gas, primarily by simply NOT allowing sufficient oxygen in to the bacteriafootnote so that they can do a complete job of decomposing the materials. MAYBE that might become a useful variant regarding providing fuel for vehicles if a lot of CNG (compressed Natural Gas) vehicles start using the roads. For now, we feel it is better to focus on TOTALLY decomposing the organic materials to get every possible Btu of heat out of them!





    We will first present here some basic (technical) information that you may want to understand: (you can skip this section if you are not interested in understanding how and why it works!)

    First, the preliminary solid scientific information that you may want to know and learn regarding Global Warming:

    These three, especially the third, are absolutely necessary for you to fully understand much of what will be presented here. There will be a number of references to that presentation rather than entirely doing each whole scientific and mathematical analysis again here.

    The General Reasoning




    That particular experiment was intended to be a preliminary one, and no source of additional oxygen was provided, which is what caused the curve to start flattening out. Other than the naturally moist cut grass, only a handful of black dirt was tossed in, as a reliable source for bacteriafootnote, nothing else! In the modest bacteriafootnotel activity that I had expected, I thought they would have plenty of oxygen for at least a few weeks. They used up most of the oxygen in the bin in a day and a half! Later experiments where a tube was added that supplies air (oxygen) show that the graph stays straight longer, and only then levels off in the 140°F to 150°F range. THAT leveling off is actually because that excess heat starts to kill off some of the bacteriafootnote doing the work, so I make a point of keeping the bin temperature under around 150°F. You might also notice an interesting detail that the ambient temperature of my basement rose a couple degrees after the warm daytime and dropped during the cooler nights, as we might expect.




    The HeatGreen Specifics

    A conventional electric water heater, set at about 170°F, uses roughly 250 Therms or $200 of natural gas or $300 of electricity during a year. We plan to entirely eliminate that cost to you, as well as then not requiring any Global Warming due to the burning of that natural gas nor in the making of that electricity. This is absolutely carbon-neutral and is a whole new level of being Green!

    Conventional water heaters have substantial energy wastage through their insulation, so the actual net heating effect is substantially less than what you are now paying for. If you add up the actual hot water used each day, it is possible to get a rough idea of how much actual heat is in a month's worth of hot water used, and for a normal family, that can be around 200 KBtu/month. But that conventional water heater uses up around 250 Therms/year or 20 Therms/month. A Therm is 100 KBtu, so this means that you pay for 2,000 KBtu of gas for heating the water, but only wind up getting around 1/8 of that in actual used hot water! The rest gets lost as radiation by the hot tank to a cool basement. (not the ideal present technology!)

    On a different subject, you may be familiar with a Compost Pile. This is where a farmer or a gardener simply piles up grass, leaves, twigs, corncobs, and other plant residues, with actually very little else even being required (although additions can make it work faster), and those materials gradually decompose, over a period of from six months to two years. From the gardener or farmer's point of view, they like the fact that undesirable scrap is removed without any hauling expense but also because what is left after the Composting is a material that is very rich in the phosphorus, nitrogen and other nutrients (called compost or humus) that all soil benefits from.

    Farmers are aware that the Compost pile generates some heat, and scientists know that different types of bacteriafootnote are most effective at breaking down the material at different temperatures. Initially, certain types of bacteria (mesophilic, which are common in the soil) do most of the work, up to around 85°F to 100°F or so. Mesophilic bacteria tend to only be able to break down certain simple hydrocarbon and carbohydrate molecules. Above that temperature, those bacteria tend to die off and a higher temperature bacteria (thermophilic, heat-loving) take over, and they are far more efficient at causing the breakdown of nearly anything containing carbon and/or hydrogen. Standard Composting practice is to try to get the middle of the Compost pile to about 55°C or 130°F, because at those temperatures, most human and animal microbial pathogens tend to be killed, which tends to make the whole process a sterilizing process (from an infectious viewpoint!) So farmers and gardeners know that it is good to have some heat inside the Compost pile, to make it work better!

    On a more technical level, the bacteria which do this process are actually doing it for their own purposes. Depending on how much oxygen is available to them, there are two very different processes which can occur. We will briefly discuss Anaerobic decomposition later. In aerobic decomposition, what we feel is more desirable, it is common that bacteria can initially convert around 40% of the energy of the glucose into Adenosine Triphosphate (ATP), which is the primary energy source found in all living things. The remaining 60% of the energy in the glucose is released as heat. The bacteria use the ATP as the source of energy for their existence. When ATP loses one phosphate group, it degrades into ADP and 7 KCalories of usable energy. Nearly all biological processes in all living things use the ATP-to-ADP process to power transmission of nerve signals, the synthesis of proteins, the movements of muscles and cell division, among many other processes. (I realize that 99.99% of people do not really care about such details!) When bacteria eventually die, this ATP and all the other components of the bacteria decompose like everything else. This has the effect of increasing the final amount of heat produced from that 60% to very nearly 100% of the amount of energy that photosynthesis first installed into the glucose. It makes the decomposition process amazingly efficient from an energy perspective. In comparison, we note that modern automobiles have around 21% overall thermal efficiency regarding the energy in the gasoline they use up (which is up from the 15% of the 1970s).

    Some HeatGreen Figures

    info-b It might be useful here to present a graph from another early experiment, also from April 2007. In this run, only leaves were used (no grass) and so it is to be expected that the bacterial activity would take longer to develop (for what farmers call BROWN compost material, rather than GREEN). This run was actually to compare the performance WITH and WITHOUT the excellent insulation around the bin.

    Notice that WITHOUT the insulation, the bin temperature rises, but rather slowly. This is actually the situation of a conventional Compost pile, where it takes months to get the CENTER of the pile up to the most productive hotter temperatures. In six days, it only rose by about 3 degrees! WITH the insulation, we can see that the leaves rose by over 20 degrees, around seven times as fast.

    The high level of insulation is a critical component to why this system works so amazingly well.

    WE are actually going to USE that heat, and even entirely focus on it! It turns out that it is the same chemical reaction heat we discussed at length in the previous presentations, specifically regarding the two-way photosynthesis and energy production processes. We learned before that each (gram-)mole of glucose can oxidize (C6H12O6 + (6) O2) where it breaks down to create (6) molecules of H2O and (6) molecules of CO2 with an amount of energy released by this decomposition being 686 Kilocalories of energy.

    We had found that the molecular weight of the glucose was 180, which means that 180 grams of glucose is one mole of that material.

    That means that when photosynthesis CREATES 180 grams of glucose, 686 Kcal of energy (from sunlight) is required, and when that glucose later decomposes back into carbon dioxide and water vapor, 686 Kcal of energy is released. In most biological functions, much of that energy is used for building cell components or transporting materials, but in the very end, it necessarily always winds up as heat energy.

    In case this technical metric stuff is losing you, 180 grams is around 0.4 pound, and the 686 Kilocalories of energy is around 2700 Btu. This means that a pound of glucose contains around 7,000 Btu of energy in it, relatively similar to the known energy content of firewood and all other organic materials (6,500 to 10,000 Btu/lb). Sorry about the technical nature of some of this stuff, but we wanted to make sure to prove why this works as it does!

    Say we arrange a big pile of dead plant (leaves, grasses, weeds, crop residues, straw, hay, corncobs, feed corn, etc) (and even animal) materials which is around four feet square by five feet high, or 80 cubic feet. (THIS is the size of the chamber that we are going to discuss below!) That material is not packed very well, so it is common that it only weighs around 20 pounds per cubic foot, or a total of 1,600 pounds of matter involved.

    We could make a quick estimate of the chemical energy in that pile of organic material as being 7,000 Btu/pound times 1,600 pounds or around 11,000,000 Btus of chemical energy (which will eventually ALL be released as heat).

    We can calculate more accurately how much energy of decomposition is in that pile. We first change the weight into metric, 725 kilograms or 725,000 grams. As we had done before, we then divide this by the 180 grams in a mole to find that we have 4,000 moles of glucose (which was initially created by photosynthesis in plants). Multiplying this by the 686 Kcal/mole tells us we have 2.8 million Kcal of chemical energy in the glucose in that pile. We can convert this back to the English system to see that we confirm that we are looking at 11 million Btus of chemical energy present. (This is a significant amount of energy!)

    This amount of energy is comparable to the amount of energy that a gas- or electric-water heater produces in around a six-month period. So we know that we have a large enough pile of material to decompose to provide all the hot water we will need! (unless we have 14 kids!)

    There is one other consideration we need to consider, how quickly the system can recover once we have drawn lots of bathtubs of hot water! We can calculate this fairly easily. We know that we have 11 million Btus produced over about a six-month period (4,320 hours). We can divide and see that our pile will be actually creating about 2,500 Btu/hr of heat. If we entirely empty out our 40-gallon chamber of 150°F water (which is enough for about six decently full bathtubs of 90°F bathwater), then we will have removed about 300 pounds of water (40 gallons) each of which had around 95 Btus of heat in it (150°F - 55°F), which means that we removed around 28,000 Btus of heat in that water. At creating 2,500 Btu per hour, we can see that it would take around 11 hours before it was ready to again supply six bathtubs of hot water! However, the pile of material has some heat storage of its own, and rather than simply removing the heat of the water, what would actually happen is that the outer parts of the pile would cool down a little, which provides some extra short-term recovery heat for the new water. The thermal conductivity of the tank would allow rather rapid transfer of heat into the water, so the tank would actually heat up top give those six new bathtub-fulls in just two or three hours, much like the performance of a conventional water heater.

    The point here is that this calculation shows that if you have a small family, you will never run out of hot water! However, if you have twelve kids and they take daily baths, and you run clothes washers a lot, too, you may need to consider a larger arrangement.


    We are greatly simplifying things here! Organic materials are not simply glucose! Plants and animals use glucose as an energy source to create all the more complex molecules that are needed for the living process. However, all those complex carbohydrates are still able to decompose into the same water and carbon dioxide, sometimes releasing even more energy that we have described here. In fact, much of the glucose is connected together in long chains of molecules into cellulose, which is the primary component of all plants. The cellulose you toss into your pile therefore actually has even more energy in it than we have been calculating. The advantage is actually an increase of around 20% extra available chemical energy.

    Firewood is a good example to prove this. It is primarily cellulose. If a pound of (dry) firewood were simply glucose, our molal calculations would show that we had 454 grams or 2.52 moles of glucose in the pound of (dry) firewood. At 686 Kcal/mole, we have 1730 Kcal/pound of wood. This is around 6,900 Btu/pound of glucose. But we know that the high heat value (dry) for firewood is around 8,660 Btu/pound. That difference is primarily due to the energy added to the glucose to bind it together into the cellulose that plants and trees use for their structure. This proves that the actual performance would be 25% better than we have calculated!

    There is also another possibility that can occur in a conventional Compost pile (which we will intentionally choose to avoid) where there is no available oxygen to participate in that decomposition. In that case, in an anaerobic process, the glucose (C6H12O6) can simply break down into carbon dioxide ([3] CO2) and methane gas ([3] CH4). This is currently considered a doubtful desire, because it forces an incomplete decomposition and therefore a smaller release of the chemical (heat) energy, but if the generated methane could be collected and compressed, it is essentially what we call Natural Gas. This might provide some limited ability to store some of the energy provided by this process, and specifically as a fuel that can burn at a much higher temperature (around 3,800°F) for possible needs of such high temperatures.

    For now, we intend to simply use the natural aerobic process to generate all the heat possible from this process. For this, we will therefore need to ensure that there is always a sufficient supply of air/oxygen inside the pile of material.

    There is one other detail to mention. The chemical reaction we have been discussing regarding photosynthesis and the opposite glucose decay have been technically incorrect. On BOTH sides of that equation are another six water molecules that are actually involved in the chemical reactions. We have left that out to simplify the equation as long as we have been discussing energy content issues, as the same molecules on both sides obviously cancel out. The main reason this is mentioned here is that a supply of water is also important inside the pile, which we will also ensure.

    We Now Have a Plan!

    All we have to do now is to make such a pile of organic material, provide it appropriate air/oxygen and water, and surround it with insulation so that we can capture all the heat that gets created! Simple!

    HeatGreen 3a - the High-Performance, Mechanized Version



    HeatGreen - Approximately a Garden Shed!

    [There IS a "crude variant" of this possible, which is described in the whole home heating page of this system. In that variant, which we call HG 1, is a "big bag" or organic material which would be placed in the basement of the house, with a pattern of 4" PVC pipe INSIDE the bag, on top of the material, which would act as the (40 gallon) hot water tank. Depending on the size of the family, that size of bag described may be large enough to provide around six months of hot water for the family with no additional maintenance.]

    We will describe here a more sophisticated arrangement that will generally resemble a conventional small storage shed. We call this the HG 2. But it will be highly insulated and it will include several other features different from any garden shed. There are MANY possible variations from this specific plan possible!

    We will make it of common, locally available materials. It will be sturdier than normal garden sheds, partly because it has to be able to contain and support around 1,600 pounds of material in its bin! The floor structure will therefore be made of 2x8 lumber, while the side walls will be made of 2x6 lumber. The top will again be 2x8, mostly so that more insulation can be used.

    NOTE: There will actually be two structures here. You HAVE to make the inner one (the bin) absolutely airtight! Inside the bin, the conditions will be extremely hot and extremely humid, where virtually anything will quickly disintegrate and decompose (which is actually the whole idea!) By making that bin absolutely airtight, you will be able to keep the moisture/humidity inside the bin, so that the space OUTSIDE the bin will be hot but actually have extremely LOW relative humidity! This being the case, the wood construction and the conventional insulation will be fine and will last a long time. However, if you should leave even a small path for humid air to get out of the bin into that space, the entire structure could quickly disintegrate as well. You do NOT want that to happen!

    These guidelines related to thickness of insulation are related to the local climate. These dimensions are generally universally useful; however, in very southern climates, less insulation might be used, while in Alaska, thicker insulation might be appropriate.

    The floor structure is a simple framing pattern using 2x8 lumber and a standard 3/4" plywood subfloor. It is made to be 6 feet square.

    With the subfloor nailed on top, the floor would look like this. It is important that it be flat and smooth, as there will later be rollers, resembling refrigerator rollers, which will need to be able to easily roll back and forth across this floor:

    We can then build the 2x6 walls, again using standard practices. We will build the walls to be 6 feet tall. Notice that there are only three walls built, with (this) front wall entirely missing! An important detail is that the boards surround that front opening be all flat and plane, as there will later be another (movable) structure with some gasketing on it that will slide in to be against that opening to seal it up.

    ALL of the inner surfaces of the chamber have conventional fiberglass house insulation installed, and then they are all covered with EITHER cheap paneling or even drywall. The important fact is to make everything air tight, where no heat can leak out.

    We can examine the heat loss that will occur given our choices of insulation and the local climate. We will have 180 square feet (floor and walls) of R-19 insulation, and 36 square feet (ceiling) of R-30 insulation. If we assume that the interior of the decomposing material is generally at 140°F and that the average outdoor winter temperature is 40°F (a Chicago winter is around 30°F in the worst part of the winter but is milder for the other months, so 40°F is a reasonable average estimate for an entire winter), then we have an average temperature differential of 100°F. Standard insulation analysis gives us a total heat loss of around 1100 Btu/hour. In our expected main six months of processing, there are 4320 hours. At the beginning and the end of the process, the maximum heat will not be generated, but this suggests that for this level of insulation, we can expect the total six-month heat losses to be roughly 4 million Btus. We knew that we had 11 million to start with, so we will wind up with 7 million Btus for us to actually use. If you think about it, that 7 million Btus really cannot go anywhere else, and so we will be able to put it to use in heating up water!

    We chose the insulation levels to provide limited losses while considering reasonable expense. You can use this same approach to see whether you might find any value in increasing the insulation to R-30 or higher.

    You have probably noticed that we have not discussed the ceiling/roof area. We are actually going to leave that up to you, with the one requirement that it be insulated to at least R-19. The REASON why we are being vague here is that there are two different approaches you could choose regarding collecting the heat in hot water.

    As with any conventional water heater, simply turning on a hot water tap anywhere in the house causes water to flow into the tank, which pushes out the heated water from the other end. Use of the hot water in the house is no different at all from when heated by any gas or electric hot water heater!

    The Other Assembly, the HeatGreen Decomposition Bin Structure

    REMEMBER: It is REALLY important that this bin be made absolutely airtight, so that hot humid air cannot get out between the two structures to cause the main building structure to disintegrate!

    There are two obvious approaches to this structure, with several other variations possible. We will discuss here making a bin out of wood and out of metal. The metal version would be more durable, but the wood version might be a better first stage to try, even though you know it may only last a year or two. It seems to allow many more options and easier changes to experiment with different arrangements of the components. So we will first discuss a wooden bin.

    Basically, we will make a bin that can fairly easily fit through the five-foot wide and five-and-a-half-foot tall opening. We will want to have it on some sort of rollers so that the rather heavy filled bin can be slid into place after filling it outdoors. This could be as simple as a bunch of loose lengths of iron water pipe laid cross-ways on the floor, or more sophisticated to actually involve casters or rollers attached to the bin bottom.

    We suggest making the bin 54" wide so that it has about three inches clearance on each side as you are moving it. The height of the bin would be about five feet. If made out of standard lumber, this would give the bin inside dimensions as close to the 4 x 4 x 5 used above in the performance calculations. (Obviously, a metal bin would be larger inside, so that around 20% additional organic material could be dumped in and therefore 20% greater total heat output generated.)

    The FRONT wall of the bin needs to have flanges extending outward on both sides and across the top. This flange will have standard door weather-stripping attached to its rear side. In this way, when the bin is slid completely in place, that area overlaps the building door frame for a good tight fit. This vaguely resembles the way a dresser drawer overlaps the dresser body hole, but without any gasketing!)

    None of the walls of the bin are insulated EXCEPT THE FRONT. The front needs to have at least R-19 insulation. One possibility for this is to make the front out of 2x6 lumber instead of 2x4 or 2x3 as the rest of the bin would be built of, so that it could have fiberglas R-19 insulation installed in it. Another possibility is to use BLUE foam house insulation, in several layers so that it is 4" thick for R-20 insulation.

    The bin must have some special features.

    The structures are now complete. The air inlet pipe stubs need to generally partly be blocked off, to keep excessive cold air from entering which might chill down the thermophilic bacteria. The temperature sensors allow constant monitoring whether the bin temperature is correct or not.

    If that temperature does not rise or drops, check the humidity, to make sure it is in the 40% to 70% range. If it is low, add water. If it is high, you have added too much water.

    If there is the smell of ammonia, that is an indication that you are not providing sufficient oxygen for the aerobic decomposition to fully occur. It is an indication that you probably need to add more air. Depending on what materials you use, they might stay tangled together (as hay seems to tend to do) where the air/oxygen cannot get to some parts of the organic material. This could indicate that the material needs to be stirred up or turned over to break up such clumps of material. The supply of air/oxygen and its ability to get to all the material is probably the most important factor to maintain.

    If the humidity seems fine and the temperature starts to drop, the only additional thing you could do would be to turn the pile, to stir up the organic material, in case some of it had not had good access to the oxygen or the water.

    If the temperature drops anyway, after an extended time, it might mean that the thermophilic part of the process is done.

    If the temperature starts to rise too high (above 150°F) then you need to NOT encourage the thermophilic bacteria! But you could try to send more (cold) air through all the pipes to try to chill down the reaction.

    To some extent, you need to find out how your own system responds to such things, so you can learn how best to help or slow the process in the future.

    There is one other possibility. If you put in things that will only decompose slowly, such as tree branches, OR if you neglected to toss in organic material that contained sufficient nitrogen, the bacteria may not be able to fully thrive, and the temperature will never rise very high.



    It might seem desirable to try to get the temperature even higher, to produce even more heat output, but there are limits. If the temperature inside the organic material gets higher than around 170°F, the thermophilic bacteria can be killed, and the decomposition process will stop, and have to start again once new mesophilic bacteria enter the area. So it is good to have it at least 130°F and probably around 150°F, but not too much above that. Some research will be needed as to the highest reasonable operating temperature.

    Now, say that you built this, and it worked, but it did not produce as much hot water as you wanted. There is actually a very simple solution! The technology of Composting has been around a long time, and there are many well known methods to get the Composting to happen faster! For example, tossing in an occasional shovel of black dirt is very helpful, primarily because it provides a lot of the mesophilic bacteria to get the process rolling. People also have learned about LAYERING the materials in certain ways, or even to include some animal manure. In an case, there are many easy ways to speed up the process that we describe here as taking six or eight months to less than half that.

    We prefer the idea of starting out with the standard natural decomposition, with the idea that it would then have to be emptied and refilled just twice a year, maybe in the Spring and Fall. A faster decomposition process might require refilling it in the dead of winter, possibly unpleasant but possibly with little source of organic material to toss in!

    An interesting aspect of the way the decomposition process occurs is that the thermophilic bacteria can decompose cellulose, fat, proteins and most other complex carbohydrates. In some cases, after the thermophilic phase ends, there is then NEW "simpler" organic materials for the mesophilic bacteria to again go after! So even after the peak temperature phase, a follow-up mesophilic phase generally again occurs.

    Even though plastics are technically hydrocarbons, bacteria generally do not do well with most plastics, and you can mess up the decomposition process if scraps of plastic are in the pile. Paper is fine, even excellent, although if the resulting humus is to be used on a garden, you should check with the newspaper regarding what types of ink they use. Some older types of ink were bad for garden plants! Ditto for any pieces of metal in the bin of organic material, generally a bad idea. See any good source on Composting for further ideas!

    However, there is a wide range of organic materials which is ideal for this process, all of which is normally considered annoying trash which needs to be disposed of! Consider the following energy contents, remembering that our glucose that this is all calculated on has an energy content of around 6,900 Btu/pound:

    sawdust8,660 Btu/pound
    corncobs9,300 Btu/pound
    coffee grounds10,000 Btu/pound
    wheat straw8,500 Btu/pound
    rice straw6,000 Btu/pound
    cattle manure7,400 Btu/pound
    bagasse8,390 Btu/pound

    (Bagasse is the material remaining when the juice is squeezed out of sugar cane, relatively similar to all the plant parts left in a farming field after a harvester has removed the crop.) Note that all of these materials have attractive energy contents, and these each decompose fairly rapidly by the action of bacteria.

    An interesting possibility is related to the fact that bacteria also decompose virtually all petroleum compounds. It is tempting to wonder if adding a small amount of used motor oil might both safely discard that material but also get extensive energy from it. HOWEVER, since that is "fossil fuel" it would very slightly contribute to new carbon dioxide in the atmosphere. Not much, but a little! It would certainly be a simple and productive way to dispose of used motor oil, which is now still an environmental problem. It also happens that used motor oil contains around 18,000 Btu/pound of energy, an attractive possible source. Another possible energy source might some day be discarded automotive tires, which contain about 16,400 Btu/pound of energy in them, although bacteria tend to take a longer time to decompose tires. Only thermophilic bacteria seem to be able to do that, and they seem really only effective if the tires were first shredded, which is a complication. Still, that seems an attractive possible energy source, from items which are currently considered a waste disposal annoyance.

    If you should become a fanatic regarding maximizing the decomposition process, you will learn about carbon-to-nitrogen-ratio, which can make life wonderful for the bacteria. You will learn about Brown and Green compost materials, which we do not see cause to discuss here.

    There are also entirely different processes that occur if the decomposition is done without sufficient air/oxygen. In that anaerobic decomposition, the process is always slow, and there are often foul-smelling gases produced. If you are properly doing aerobic decomposition, with moderately close C-N ratios, there should be virtually no smell created.

    If you should ever decide to stop using this system, and your climate is cold enough where water would freeze, you would need to make sure to drain all the water from the pipes or radiators or tank. But this is all designed so that even if you foul up in this regard, replacing a burst water tank or burst pipes should not be unusually involved. In fact, the entire system is designed for good durability and minimal maintenance.

    This concept has one large difference from conventional Composting. In a normal Compost pile, so much heat is constantly lost that the only part of the pile that is around the 130°F to 150°F range is a small section near the very middle. Since THIS system has such effective thermal insulation surrounding all of it, the entire pile can be at those temperatures. That means that the thermophilic (heat-loving) bacteria can thrive everywhere and not just in a small portion, so that the entire decomposition process can occur several times faster than usually expected. It may be found useful to actually slow down the process! One way to do that is to remove the created heat quickly enough to cool down the pile. But you may not need that extra heat! Another way seems to be related to restricting the access to fresh oxygen. This will work, but it can have the side effect of causing anaerobic bacteria to develop, and methane and several smelly other products to be generated. The only real disadvantage of this unexpectedly high performance would be that the material of the decomposing pile might then not last the intended six months, where it might require refilling at shorter maintenance intervals. It would have an advantage of producing several times as much output heat as this presentation has calculated.

    There is another interesting possible benefit of this system. Carbon dioxide has a density that is much higher than air or oxygen, around 1.5 times as great. Our bin has very little air flow inside it. This suggests that the generated carbon dioxide should tend to settle down to near the bottom of the bin. This suggests an interesting additional benefit! Say that the bin was built where the perforated air tubes were installed higher than described above, but that two additional perforated tubes were placed laying on the floor of the bin. All these tubes would have the caps and/or air restrictors blocking them off.

    This device should produce an average of around 4.7 cubic feet of carbon dioxide every hour. It cannot be pure carbon dioxide but is limited by Dalton's Partial Pressures to around 4.4% of the air. This indicates that there could be around 110 cubic feet of air saturated with carbon dioxide which accumulates near the bottom of the bin every hour, air which has a carbon dioxide content of around 110 times that which exists in the natural atmosphere (44,000 ppm rather than 380 ppm). The reality of this system is that the airflow is generally around 2.5 times this, which makes the local concentration of carbon dioxide around 40 times the natural concentration.

    So say that a very small fan is provided which could extract this gas. The removal of that gas would draw in new fresh air through the higher-up tubes, to supply the thermophilic bacteria the oxygen they will need. But we now could have a supply of carbon dioxide rich air.


    They found that fruit quality was improved as well, and the total sugar accumulation in the fruits, especially sucrose was increased and that titratable acid content was reduced. Essentially all wonderfully desirable results!




    (Some of those researches have found that carbon dioxide concentrations higher than around 1200 ppm are NOT as beneficial.)

    Yet another possible Green benefit from this system!

    You might note that this combined system actually collects the carbon dioxide that is naturally generated anyway, and then it allows those greenhouse plants to REMOVE IT FROM THE ATMOSPHERE! This is a tiny effect, but it actually tends to remove some of the excess carbon dioxide that we have put into the atmosphere due to our massive burning of fossil fuels!

    There is an interesting technical concept that may only interest Thermodynamicists! But where conventional burning always leaves the water vapor that is created from oxidizing the Hydrogen in the fuel as a hot gas, this system generally has the water vapor condense as water due to the very low operating temperature. This difference is actually significant. Since we wind up with liquid water, we use the HHV (high heat value) for the fuel involved, where there is 61,000 Btus of energy per pound of Hydrogen involved. In all conventional burning, the hot exhaust gas carries away the latent heat of vaporization of the nearly nine pounds of water created from each initial pound of hydrogen in the decaying matter. Therefore, conventional burning loses access to over 9,000 Btu/pound of hydrogen, only being able to benefit from the LHV (low heat value) of 51,600 Btu/pound. This is quite an advantage of our system! There are also no losses due to high temperature chemical dissociation during a burning process.

    There are some variables which exist. Exactly what kind of organic materials you include in your pile affects how quickly and how completely it will decompose and generate heat. In general, normal Composting only decomposes around half the volume of a Compost pile, so the energy production would only be around half of what has been calculated here. However, that is primarily true because only a very small portion of a standard Compost pile is actually hot enough for the most efficient thermophilic bacteria to thrive. Because of the extensive thermal insulation we surround this with, the thermophilic bacteria can thrive throughout the entire pile of organic material, and not just in the center. This has two major effects. One is that the decomposition is generally far more effective and efficient than in conventional Composting, where much less material remains after the process has completed. The second is that the entire decomposition process can tend to work far faster than we have described above.

    This second enables production of FAR more heat than was described above, for much greater usable heat output, but it also then consumes the organic matter far more quickly! One of the basic desires of the system as described above was to not need any maintenance at all for the six month period of a winter (October through March). If the system is operated in a high-performance mode, it might produce ten times as much heat output per hour, but the organic materials would then be consumed ten times as fast, in three weeks instead of six months. Is that desirable? Each owner would have to decide that! To be able to generate enough heat to heat an entire house from a garden-shed-sized system is certainly an attractive idea, but to then have to empty and re-fill it every three weeks during the winter does not seem very enjoyable!

    We have described the density of collected organic materials as being around 20 pounds per cubic foot. However, it might be less than that, depending on your methods. If grass clippings are not "squeezed" into a container, 10 lb/cf can be more normal. Also, what we are interested in is the actual weight of organic material, and if you collect sopping wet leaves, much of the weight might be just water leaving less of actual organic material.

    We have described the bacterial activities as being entirely decomposition of the cellulose and glucose into water vapor and carbon dioxide. That is not entirely true, as the bacteria are actually doing this for their own purposes, including growth, so there is a percentage of the gross heat produced from the decomposition that gets used for the growth of the bacteria themselves. However, those bacteria will eventually die and decompose, and so that effect tends to become minimal.

    We actually have materially altered the normal process of decomposition. In normal Composting, once the thermophilic bacteria have completed their high temperature work, they tend to die off, which allowed the mesophilic bacteria (remaining in cooler portions of the Compost pile) to quickly re-multiply and do the remaining lower temperature decomposition. But since we have enabled the entire pile to get up to the high temperatures, there really are virtually no mesophilic bacteria that can still be alive anywhere in the whole pile! Instead of the temperature dropping from the 150°F to 85°F for the final phases of the decomposition, it might instead drop to ambient, until and unless some mesophilic bacteria are again able to enter the scene.

    However, this absolutely natural process is SO effective at creating heat energy, that no matter what you do, you are certain to get great benefits!

    Making Electricity




    This concept can be applied in a thousand different ways, depending on local conditions and availability of materials. The actual requirements are: (1) a reasonably airtight chamber that includes substantial thermal insulation; (2) a bin or chamber inside that which is also airtight which contains nearly any assortment of organic materials; (3) a supply of water within this bin; (4) a few handfuls of black dirt for a supply of needed bacteria; and (5) a provision for a rather small airflow through the bin, to provide oxygen and to remove carbon dioxide.

    This could be created above ground or in the ground. In a remote Third World location, bales of straw might be used as the insulation, or many other locally available materials. The chambers should be resistant to rats and larger animals chewing through, either to get to food scraps or to a heated location during a winter. A thermometer is very useful because there is a common tendency to cause too great an airflow through the bin, which then does not allow the material to get up to the most effective operating temperature. Also, given the extreme amounts of heat energy which gets generated, overheating and killing the thermophilic bacteria can occur without knowledge of the temperature actually within the decomposing material.

    This concept has only very recently been invented (February 2007). It figures to take two to three years before rigorous University Research Studies can be done to fully document it. If you have read the contents of the four associated web-page presentations, it must be clear that I am not sure the planet or civilization actually HAS an extra two or three years to delay in doing this. This presentation has tried to refer to the many hundreds of years where standard Composting has been done, where farmers have realized that heat develops in the middle of a decomposing organic pile. We have tried to also present the appropriate Biochemistry and Physics so that a reader might understand the science behind WHY it works. We have tried to present the math, in a relatively painless way, such that any reader might confirm or deny for him/herself the validity of this reasoning and the numbers presented.

    So, each reader is free to wait those several years until University Research Studies prove it. However, we hope that we have presented things sufficiently so that many people will not see the need to wait those years and might decide to build this fairly simple system sooner. If so, and you decide to do this, you will certainly have your own ideas about how to do certain things. You might decide to install more or fewer tubes, of larger or smaller diameter. You may decide that the whole thing should be tall and skinny or short and wide. You may decide that there is some reason to tilt the whole thing! It will certainly work in any case! Maybe better or maybe not. We hope that people who try variations of what we have described will later e-mail us regarding any potential variations or improvements, and the actual results you achieved. If we could have a thousand people each doing this during this coming winter (07-08) and the next (08-09), we think we may be able to greatly refine the system, even before any official Research Studies get even initial data.

    A few newscasts are starting to finally indicate how urgent and how drastic our problems are regarding Global Warming. If we wait for the governments to act, as slowly as they always seem to work, even their optimists are only expecting to make modest reductions by the year 2050. That will certainly be FAR too late. The premise of this page and this concept is that if instead a "grass roots" effort of countless millions of homes being heated in this way, we might actually be able to achieve in two or three years what Politicians seem to only dream about for more than 40 years from now! When TV ads say for you to "do your part to save the planet", this is the sort of thing they are probably intending to refer to!


    Alternative GREEN Furnace with no Fire - Non-Fossil-Fueled HeatGreen - A Simple, Non-Fossil-Fueled Home Heating Furnace (heating your home, for free and with ZERO Global Warming consequences!


    Such a Huge Amount of Free Energy?





    The actual natural heat production is very irregular, as the mesophilic bacteria which operate at the lower temperatures are very affected by the temperature of the material they are trying to break down for energy. On intensely cold days, there is extremely little activity, while on milder Spring days, substantial decomposition occurs.

    Note that the technology which we have developed generally relies on entirely different types of bacteria, the so-called thermophilic ones. They are far more efficient at the process BUT they also require an environment which is around 125°F to 150°F. This means that they rarely get a chance to do much, except on really hot sunny summer days when inside a pile of animal dung or similar Compost materials. This actually explains why the thick and effective insulation is so centrally important in the operation of this concept. If there should ever be found some bacteria which thrive on even warmer temperatures, like 170°F to 180°F, it figures that they might be even more rapid in accomplishing these functions. If there were ever to be any future in using this approach for vehicle fuels, that might a likely way to accomplish the rapidity needed in the energy release.



    Carbon Footprint










    Burning Coal






    Production of Electricity from Coal























    Combustion of Gasoline


    Burning Natural Gas





    Carbon Cycle







    graphic from John W Kimball


    The Carbon Cycle is a CYCLE because, when the plants later die, they then naturally decompose (or which also occurs during a common process called Respiration) (with the help of many types of bacteria) back into carbon dioxide and water (or water vapor, the same thing). After an entire Cycle has occurred, the amount of Carbon has not significantly changed.







    C + O2 which gives CO2.



    Solvay Process





    This Year's WORLD Carbon Dioxide Estimate







    Your Heating Bills






    A VERY Technical Footnote

    Unless you either are familiar with Thermodynamics or enjoy pain, it might be best if you avoid this next section!

    The other calculations in these connected pages were generally from the approach of Biochemists. The following is more strictly pure Physics. (Except for the fact that we will try to stay in the more familiar American units of measurement.)

    We learned earlier that a mole of glucose is 180 grams and that it produces 686 Kcal or 2,722 Btu of energy. This is 15.1 Btu / gram of the glucose.

    We also know that the chemical reaction is C6H12O6 + (6) O2 produces (6) H2O + (6) CO2. The six moles of oxygen are provided by air, which is only 21% oxygen and 79% nitrogen, which means that we also have 22.6 moles of nitrogen, which do not participate in the reaction but will have to be heated up along with the other produced gases.

    For calculations, we will assume that the air enters at 60°F. The thermal capacity of each gas is available in charts or equations for any temperature. For example, the heat capacity of Oxygen gas (between room temperature and 5,000 degrees) is given by 11.515 - (172 / (T0.5)) + (1530 / T) [where T is the absolute temperature R and the result is in Btus per pound-mol of the gas]. Specifically (in Btu of energy in the gas per gram):

    520°R or 60°F000
    580°R or 120°F0.6630.6500.934
    600°R or 140°F0.8850.8701.256
    700°R or 240°F2.4451.9742.907

    Therefore, our 6 moles of water vapor is 6 * 18 [molecular weight] or 108 grams. Given the values in the table above, we know that that amount of water vapor must contain 108 * 0.663 or 71.6 at 120°F or 108 * 0.885 or 95.6 Btu of energy at 140°F. We can do the same for the other gases and other temperatures, finding that we have 6 * 44 or 264 grams of carbon dioxide and 633 grams of nitrogen.

    We therefore can total up the heat which must be transferred to the gases, to raise them to a specific temperature, which necessarily participated in the chemical reaction as follows:

    Gas 120°F 140°F 240°F 260°F
    Water vapor 71.6 Btu 95.6 Btu 264.0 Btu 297.4 Btu
    Nitrogen 408.4 Btu 550.6 Btu1271.0 Btu1415.1 Btu
    Carbon dioxide246.6 Btu 331.5 Btu 767.6 Btu 854.8 Btu
    TOTAL 726.6 Btu 977.7 Btu2302.6 Btu2567.3 Btu

    We know that the mole of glucose will produce 2722 Btu of heat. However, the water vapor created must be evaporated with some of that heat, which is easily calculated as being 249.8 Btu. (That water vapor will later condense in other parts of the decomposing pile which recovers that energy.) So we have 2472 Btu of heat which must get taken away by the gases created. We can interpolate to learn that the maximum possible temperature of this process would be 253°F, given this situation of no excess air being provided. Of course, the bacteria would all have died far before that and this is merely the theoretical maximum possible.

    It is more desirable to provide excess air, to increase the chance that each reaction site will have sufficient oxygen present and to reduce the chance of anaerobic decomposition. If we provide 50% excess air, these calculations are altered where another 14 moles of air which would have to be heated. This causes the maximum theoretical temperature to be lowered to 204°F.

    Similar calculations show that if we provide greater than around 200% excess air, there would be so much cool air passing through the decomposing material that it would not be able to maintain the desired 150°F for the thermophilic bacteria to thrive. This gives a maximum limit to the airflow. It also provides a guide for how much airflow is necessary in the event that the temperature starts to exceed the 150°F where the thermophilic bacteria might be endangered, to rapidly cool down the pile. In other words, the size of a suitable blower that might be automatically started by an excessive temperature inside the pile.

    We have shown here that it is not theoretically possible to have this concept create heat above around 250°F. This establishes that the performance of the decomposition is limited by the survival of the thermophilic bacteria.

    We also know that six moles of oxygen is needed for the aerobic decomposition of each mole of glucose, which is 192 grams of oxygen. At the incoming temperature, this oxygen takes up around 5.5 cubic feet of volume. The incoming air therefore takes up around 26.2 cubic feet for each mole of glucose fully decomposed. If we have a situation where we have 25,000 Btu/hour being created, we know that we are decomposing around 9.2 moles of glucose (about 3.6 pounds) each hour, which therefore requires 240.5 cubic feet per hour, or around 4 CFM of incoming airflow. With 50% excess air, that would be around 6 CFM of incoming airflow. The outgoing airflow is slightly greater (about 20%), due to the higher temperature and the greater number of moles of gas leaving.

    These are very minimal airflows and do not really need any significant blower (nearly all of which move over 100 CFM of air), although a computer cooling fan might be useful. As noted above, it is undesirable to inject greater than 200% excess air (12 CFM in this case) due to excessive cooling of the pile which would adversely affect the rate of decomposition and energy production.

    We can use a Physics approach to confirm something else we have discussed. We have discussed the Biochemical understanding of glucose, C6H12O6. Physics tends to look at it a little differently. The six Carbon atoms in this molecule are each considered as a pure fuel. Since these atoms each have an atomic weight of 12, we have 72 grams of this fuel. We know that each gram of pure carbon will give off 31.05 Btu if it is burned (oxidized). So we can say that there are 2235 Btus of heat from this fuel. The twelve Hydrogen atoms are also considered as fuel, each with an atomic weight of 1 so we have 12 grams of this fuel. Each gram of Hydrogen will give off 134.43 Btu if it is oxidized. We therefore have 1613 Btu of heat from this fuel, giving us a total of 3848 Btu of actual energy (per mole) present which might be released. This is 21.4 Btu / gram or 9700 Btu / pound.

    Actual processes are never perfect, so all that theoretical energy cannot be actually obtained. We saw above that only around 2722 Btu of available chemical energy is actually involved in the glucose molecules. Any real organic material has components that are not C, H, or O. Some is material that is not organic related at all, considered ash after combustion. Other involve elements that get used in many complex organic molecules for specific purposes, such as the iron that is critically important in our blood, or the many other trace elements like that. Also, nitrogen from the air gets used in many organic molecules, as do phosphorus and other elements that are critically necessary (and even supplied to soil as needed nutrients!) Finally, especially in combustion, it is not possible for every molecule of oxygen from the air to be precisely where it is needed to enable the oxidation of every atom of carbon or hydrogen, so there is always necessarily some incomplete combustion, where some carbon and hydrogen is always left after such an oxidation. The Physics approach only looks at the theoretical maximum possible, meaning all real values have to be slightly less!

    This is useful here in order to evaluate cellulose a little better. Cellulose is a long string of C6H10O5 assemblies (slightly modified glucose molecules linked together). With this analysis approach, we can see that we still have the same amount of Carbon fuel, but now ten Hydrogens instead of twelve. We therefore have a total of 3580 Btu of theoretical energy. Since this molecule has lower atomic weight (162 instead of 180), it contains slightly HIGHER energy per unit weight, 22.1 Btu / gram or 10,000 Btu / pound. This is the theoretical reasoning behind why cellulose has a higher energy content than glucose. It also shows that all actual fuel materials (as presented above) have slightly lower actual HHV measurable quantities than the theoretical energy contents of the fuel components themselves!

    We can also add here the specific information for cellulose rather than the glucose we had generally been discussing. The following is generally available information, for example from the Incineration section of Mark's Standard Handbook for Mechanical Engineers.

    The molar description of the cellulose decomposition:
    C6H10O5 + 6 O2 gives 6 CO2 + 5 H2O
    is 72 + 10 + 80 + 192 = 264 + 90 (by separate elements weight)
    or 162 + 192 = 264 + 90 (by molecule weights).

    By ratios to carbon, this is 1 + 0.14 + 1.11 + 2.667 = 3.667 + 1.25
    By ratios to cellulose, it is 1 + 1.185 = 1.63 + 0.555

    For calculating the needed air, first determine the needed oxygen for each of the carbon and hydrogen:
    carbon: 12 + 32 = 44
    ratio: 1 + 2.667 = 3.667

    hydrogen (full molecules): 4 + 32 = 36
    ratio: 1 + 8 = 9

    For a (gram-)mole of cellulose, 162 grams, we therefore need an amount of oxygen equal to 72 * 2.667 + 10 * 8 or 272 grams. If the air is 23.15% oxygen, this means we would theoretically need 1175 grams of air. The air generally does not perfectly go to where it is needed, and so EXCESS AIR is always provided, in this case, 40% excess air is suggested. This is now 1645 grams of air that should be provided for each 162 grams of cellulose that is to be completely decomposed.

    This is 10.15 pounds of air that should be provided for each pound of cellulose, or around 132 cubic feet of air. These figures are similar to the calculations presented for glucose decomposition. For the 25,000 Btu/hr production we calculated above for the glucose, we get slightly greater needed airflow, but still around 6 cubic feet per minute.




















    This presentation was first placed on the Internet in March 2007.

    Energy-Related presentations in this Domain:

    Self-Sufficiency - Many Suggestions A thorough presentation
    Electric Power Plants - Climate Effects
    Global Warming Effects of Carbon Dioxide
    Hydrogen as a Fuel for Vehicles. (August 2003)
    Conserving Energy - Methods and Processes
    Energy Storage - Methods - Efficiencies Various Methods
    Solar Energy - How Much Energy Comes From the Sun
    Global Warming and Climate Change - Possible Solutions
    Energy from the Moon - A Version of Tidal Energy Collection. (Artificial Tides) (1998, 20a href0)
    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:

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