A Simple, Inexpensive and Non-Fossil-Fueled Water Heater

You may want to read this VERY carefully! Why? Because if EACH of us 75 million American families chooses to use (both uses of) this system, and we can each reduce our family's Carbon footprint from our current average 10 tons per year down to around 3 tons per year (which is mostly from our vehicles), that means "we", on a Grass Roots level, can eliminate (75 million * 7) over 500,000,000 tons of carbon dioxide emissions from the United States each year! This is a 25% National reduction from the two billion tons that the U.S. currently sends into the atmosphere (due to burning fossil fuels). Isn't that great? Politicians HOPE to reduce our National emissions by a few percent by the year 2050, but WE citizens and homeowners could reduce it by 25% by the winter of 2008-09! (I LIKE that!)

It seems likely that governments will love the fact that WE can create that 25% total reduction in the United States' total carbon dioxide emission without needing a DIME of any government's money or any money from any giant corporation! (I REALLY like THAT! No "billions of dollars of our taxpayer money" are necessary; not even a dime!)

Some of us live in milder climates, but if we 75 million American families now average $1,500 for winter and hot water heating, then please note that "WE" will collectively pay around $110 billion THIS winter, which goes to giant corporations and Mid-East countries, where NEXT winter, we could pay them ZERO! This should all appear as a win-win-win-win-win situation, except for those Mid-East countries and the Execs of those giant corporations!

By the way, we 75 million Americans currently average using up around 80 million Btus each of heating oil or natural gas each winter. Multiplying, this is around 6 quadrillion Btus of fossil heating fuels. Noting that the U.S. IMPORTS around 26 quadrillion Btus of fossil fuels (mostly petroleum, around 70% of all the petroleum we use up in this country is imported) each year, our individual decisions to heat our homes at minimal cost even has MORE benefits, regarding substantially reducing our dependence of imported fuel supplies!

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!

It is extremely likely that WITHIN 60 PACES OF YOU RIGHT NOW, there is a MASSIVE energy source which is absolutely FREE! It is on the scale of 67,000 horsepower-hours of (heat) energy! Or 50,000 kilowatt-hours (again, of heat energy). Or 170,000,000 Btus. That's an astounding amount of heat energy! It is totally free AND it replenishes itself NATURALLY every year!note 1 You probably collect and bag grass cuttings when you mow your lawn, as millions of others do. You call it Yard Waste! And you rake and bag leaves in the Fall. What if we told you that as all those leaves and cut grass blades decompose, they NATURALLY give off heat. A LOT of heat! In a single acre of lawn, forest or even weeds, the total amount of heat which IS NOW being released (over about a six-month period of decomposition) is around that 170,000,000 Btus. That's an astonishing amount of heat energy! YOUR innocent-looking yard has available an immense amount of absolutely NATURAL and GREEN heat energy, which is NOW being constantly released by simple natural decomposition of organic materials. All this while YOU are paying billionaires in Saudi Arabia for heating oil??? Take a look out your window at your yard! What if we now told you that every one of those bags of leaves or grass is therefore worth $3 or $4 or more? You probably now pay giant corporations around $2,000 every winter for fossil fuels to heat your home. Consider this: A 20-pound bag of ANY organic matter contains around 180,000 Btus of chemical energy, which was captured from sunlight by the photosynthesis of carbon dioxide and water vapor, and which will ALL necessarily be released as heat as the material naturally decomposes! We have Engineered a method of CAPTURING a large portion of that heat, to either heat your home or to heat your domestic hot water! You probably now pay at least $4 for heating oil or $3 for natural gas to heat your home - as much as one bag of that Yard Waste could easily provide. Do you still want to pay someone to haul those bags away? And ... the biggest bonus of all, by eliminating your need for fossil fuels, you will be contributing toward solving the global warming catastrophe.

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:

• The Strict Science and the Calculations, which you can confirm.
• Possible Approaches to Reducing Carbon Dioxide in the atmosphere.
• Narrowing Down the Specifics to Actual Possible Applications.

The General Reasoning

• We need to remember that virtually all of modern society is powered by "fossil fuels", petroleum, natural gas and coal. We BURN these fuels, which breaks down (oxidizes) the hydrocarbons those fuels are made of. If these burning processes are done well, they break down into always the exact same two things, carbon dioxide and water vapor, and they give off the energy that we then use.

• We use up astounding amounts of fossil fuels each year, such that we are currently generating around 8,000,000,000 tons of carbon dioxide which is going into the atmosphere, and greatly causing the Global Warming situation. (Each American home/family annually consumes enough fossil fuels to directly generate around a ten-ton "carbon footprint")

• This first seems to be a hopeless situation, and it may actually be, as per the discussions in those other web-pages. However, there is one HUGE positive situation! In all we do to use up oil and natural gas and coal, where we generate 8 billion tons of carbon dioxide, NATURE produces 300 billion tons of carbon dioxide each and every year! (We are comparative amateurs!) (NOTE that there is a HUGE difference! All the carbon dioxide that Nature releases each year had been REMOVED from the atmosphere earlier that year when the plants were growing. That BALANCE of CO₂ removed and replaced [- 300 + 300 totals zero] is the basis for the stability of what is called the Carbon Cycle. When WE burn fossil fuels, what we are really doing is rapidly releasing CO₂ that had been removed from the atmosphere over millions of years. NATURE is operating a balanced system. All WE do is add and never remove, partly because we really do not know how to do it very well! Even though we only are producing 8 billion tons, it is [ - 0 + 8 ] which means another 8 billion tons of carbon dioxide is added to the atmosphere every year.)

  The REALLY interesting part is that it is the EXACT SAME CHEMICAL PROCESS of oxidation that is occurring as we do in burning our fossil fuels! It creates the same carbon dioxide and water vapor and energy. It's just that it occurs much, much slower. So slow that virtually no one ever even notices it. But it NATURALLY creates around FORTY TIMES all the energy that all humans now use up!

• So the trick is to allow the natural process to proceed but then capture this vast amount of heat that is produced. It turns out not to be that hard to do! This presentation includes the complete instructions so that YOU can benefit from this previously untapped energy source.

• And, what IS this vast energy source that no one has even NOTICED before? It is the natural decaying of organic matter! The leaves and cut grass in your yard gradually decay and decompose. You know that! They disappear! And you know it is because they rot and decay! Into carbon dioxide and water vapor, as discussed in the other presentations and below. YOU probably never even realized that those dead leaves and grass were also giving off any heat! It certainly does not seem noticeable! But if you have some trees and a moderate-sized lawn, where the total amount of leaves and grass over an entire year is just 500 pounds, you will see below the logic and the calculations that PROVES that that lawn material will RELEASE OVER FOUR MILLION BTUs OF HEAT in the process of that decomposition! (This is a significant amount of heat!)

  Do the math! You mow your lawn each week, for maybe 25 weeks. Even if you only get ONE bag each time, there's your 500 pounds! You certainly have far more than that available, if you actually collected it all.

  That heat is not noticed because it is created slowly, over months, and over a large area, and winds and rain carry away and distribute that heat so that no one can tell it is there. But it IS there!

• If you are familiar with the garden or farm process of Composting, you might already see the next step! A gardener PILES UP such grass and leaves into a Compost Pile. He doesn't actually have to do anything else to it, and bacteria inside the pile start decomposing the glucose and other carbohydrates of the organic matter. This produces some heat, which gardeners and farmers are VERY aware of! But NOT because it is heat, but because the greater warmth inside the compost pile makes it decompose faster! So farmers and gardeners have known about the heat created in organic decomposition for centuries, but have only used it to speed up the composting process (to wind up getting more and better fertilizer called humus).

• We are going to do a very similar thing, except in a higher tech sort of way, where we are going to capture every Btu of heat that we can! Just imagine a Compost Pile on steroids! But without some of the well-known drawbacks such as unpleasant odors. Also, interestingly, since we are going to carefully make sure that plenty of oxygen and moisture is always available to all the bacteria, and plenty of warmth, it turns out that the decomposition process we do is FAR more complete than what farmers do! In fact, where farmers TRY to have humus remaining when they are done (the central point of Composting), WE try to have such complete decomposition that virtually NOTHING is left afterward! Many scientific experiments have shown this to be true when the temperature is 88ºF or above, and when plenty of moisture and oxygen is available, which was considered important in explaining why very little humus is ever found under tropical rain forests!

  Gardeners and farmers will say that the composting process takes between six months and two years to complete, and that only around half of the weight of the material disappears. The remaining material is the humus or compost that they actually want, the material they then spread in their gardens or fields as a sort of fertilizer. However, most gardeners and farmers are not aware that there are "fast" ways to do composting. Some operations use an assortment of ways of tumbling the material in rotating drums, (such as what is referred to as In-Vessel processing) or with other devices (such as Tunnel Composting), and get the entire composting process to complete IN JUST 48 or 72 HOURS! They have also found that with certain conditions, it is possible to have the decomposition process proceed to nearly completely consume ALL the material rather than just half.

  Actually, our process does NOT actually resemble what is called Composting, except for the fact that the basic chemical decomposition reaction is the same. Other than that, there are hardly even many similarities! We do NOT have significant material (humus) remaining and we do not need six months or two years to accomplish the process!

  We do not see great value in having our home heating system perform quite that well, although it definitely can and has been experimentally proven to do so. A rather small system could be made that could only hold around 300 pounds of organic material (not much larger than a recliner chair), with that highest performance built in. The 2.7 million Btus of heat energy created is sufficient to entirely heat a fairly large home for the three days that it would be producing that heat (the 72 hours), but then that would mean that another 300 pounds of material would have to be loaded in every three days during the coldest part of the winter. That seems undesirably labor intensive.

  Therefore, we describe systems below that are (generally) larger than that, with capacity for around 1500 pounds (for several weeks or a month of whole house heating before maintenance is needed) or capacity of around 9,000 pounds to provide all the heat needed for the entire six months of winter. A high-performance system IS included in the choices of what you can make.

You can see that the grass continued to rapidly rise in temperature, all because of lots of very active bacteria, and just 24 hours after I had dumped that newly-mown grass in the bin, the average temperature of the bin crossed 120ºF! I still find that mind-blowing!

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 bacteria, nothing else! In the modest bacterial 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 140ºF to 150ºF range. THAT leveling off is actually because that excess heat starts to kill off some of the bacteria doing the work, so I make a point of keeping the bin temperature under around 150ºF. 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.

In case it is not clear, THIS is a "carbon-neutral" situation. Plants live and grow, and REMOVE 300 billion tons of carbon dioxide from the atmosphere every year, naturally, by photosynthesis, in forming the glucose and other organic molecules of life. When that material dies and decomposes, it completes the cycle, what is called the Carbon Cycle. Fossil Fuels cause a problem because they had removed their carbon dioxide from the atmosphere many millions of years ago. The fact is that we are now mining and pumping all the fossil fuels we can find, and then burning them at very high rates, that now releases huge amounts of carbon (dioxide) that had been trapped in those fuels for those millions of years. The carbon dioxide itself is not a problem! The fact that we are RAPIDLY ADDING a lot of "new" carbon dioxide to the atmosphere IS! The organic-decomposition-based concept here is entirely different, simply keeping the EXISTING carbon in the biosphere and atmosphere in circulation. Totally NATURAL and Carbon-neutral.

Those materials were going to decompose NATURALLY anyway! We are just causing that natural process to occur where we can capture the heat it creates.

The HeatGreen Specifics

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 bacteria 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 85ºF to 100ºF 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 55ºC or 130ºF, 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

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 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 150ºF water (which is enough for about six decently full bathtubs of 90ºF bathwater), then we will have removed about 300 pounds of water (40 gallons) each of which had around 95 Btus of heat in it (150ºF - 55ºF), 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 therefore going to enable that entire pile to decompose, essentially naturally, over maybe six months (or faster), where the glucose (C₆H₁₂O₆) oxidizes aerobically [chemically combines with oxygen from the air] ( the 6 O₂ molecules) and therefore breaks down to create ONLY molecules of water (H₂O) and carbon dioxide (CO₂) and a MASSIVE release of energy!

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 3,800ºF) 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!

HeatGreen 3a - the High-Performance, Mechanized Version

Our research is actually starting to suggest that this version has some real advantages over the others presented here, as well as being fairly small, about the size of an upright piano.

HeatGreen - Approximately a Garden Shed!

We will describe here a more sophisticated arrangement that will generally resemble a conventional small storage shed. 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 140ºF and that the average outdoor winter temperature is 40ºF (a Chicago winter is around 30ºF in the worst part of the winter but is milder for the other months, so 40ºF is a reasonable average estimate for an entire winter), then we have an average temperature differential of 100ºF. 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.

• The first is to build a flat roof, the simplest possible construction, just like the floor! This will provide about a foot-tall-space near the ceiling to HANG air-to-water heat exchangers, such as the hydronic room radiators, or even just large quantities of 4" PVC pipe and elbows. In general, you should NOT use car radiators, even though they would be perfect, because many of them contain lead solder that could contaminate your house hot water. But, for example, exploring the 4" PVC pipe, if the entire ceiling was covered with one layer of such pipe, it would be around 60 lineal feet of pipe, which would be able to contain a total of around 40 gallons of water! At both ends, PVC reducer couplings would connect it to standard sized plumbing pipe. If two layers of the pipe were installed, the capacity would be around 80 gallons of hot water, as for a really big family. However, remember that water is heavy, and if you expect 80 gallons or 600 pounds of water to stay against the ceiling, the pipes must be mounted really sturdily.

  Note that this small structure must NOT be inside the house (mostly because of the possibilities of odd smells from the decomposition depending on what you pitch into it) but it should be as near the house as possible to shorten the plumbing connections. Those connecting pipes need to be extremely well insulated, at least R-50 and higher if possible.

  This arrangement involves very little headroom, where the heat collecting tanks/pipes/radiators are all within a few inches of the ceiling. That permits the flat roof.

• The other choice is to make a peaked roof (front to back). The possible reason for wanting to do this is simple, it allows more headroom! A discarded hot water heater (which does not have any leaks!) could have its heating element removed and the housing and insulation removed as well, to get down to the bare water tank. A 30 or 40 or 60 gallon water tank could then be suspended from the roof structure, horizontally, with the tank high enough that it would not interfere with the decomposition bin that will be slid in under it.

  Interestingly, the installed T-P valve (temperature-pressure valve) is not needed, since this water heater could never get the water up to boiling! Again, the in and out pipe connections would go to the nearby house through highly insulated pipes.

The Other Assembly, the HeatGreen Decomposition Bin Structure

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.

• First, the floor area must be absolutely waterproof. There are many ways to accomplish this, from as simple as a heavy plastic tarp to lining it with metal. There is actually some advantage in the entire bin being completely waterproof, to keep the high humidity and high temperature inside from quickly affecting all the wood of the structure.

• Next are several lengths of "PVC field drain pipe". This is a standard 4" PVC pipe that has lots of holes in its sides. You also need a "closet flange" or the equivalent for each one of these pipes. These pipes will provide fresh air and oxygen for the aerobic bacteria. It is not obvious just how many such pipes are best, and I initially suggest four. Two would be installed relatively low in the bin (front to back) and two just above half way up. The closet flange would be screwed to the REAR INSIDE WALL at the appropriate location. A 4" diameter hole would be made in the FRONT WALL to line up TWO INCHES HIGHER than the flange. The pipes are removable.

  To start with, none of them are in the bin, and filling is begun. Once the organic material got up to around the height of the lower pipes, they would be slipped in through the front hole and jammed into the closet flange. (The bought 10-foot-long pipe having been cut so that it extends about 6" past the front outer wall.) The holes in the pipes should be lined up top and bottom. More material is tossed in the bin, and the upper pipes slipped in at the appropriate time. This allows filling the whole bin without any void spaces under the pipes. When the whole process is done, these pipes may be easily removed so that the resulting humus can be removed from the bin so the next filling can be made.

• A source or provision for a small amount of water supply is needed. As long as the pipes slope downward toward the rear, and as long as there are pipe holes on the bottom, providing this water can be simple. Any (small) hose or pipe can extend into the outer open end of the pipe stubs sticking out the front of the system, to dribble water in as desired. The water would run down the slight slope and drain out through the holes into the pile of organic material.

  Water flow rate might be experimented with. A very slow flow tends to cause most of the water to drain out through the first hole in the pipe, while a surge of water tends to go all the way to the end and pool there before draining out at the last holes. A mid-flow-rate can get water to drain out fairly equally along the dimension of the pile.

• Each of the PVC field pipes needs to have two additional things. Places like Radio Shack sell $10 remote digital thermometers. The probe is on about a six-foot wire, and this wire is run through the INSIDE of the PVC pipe, it passes through one of the (top) holes in the pipe and is securely strapped to the outside of the pipe. This location interferes with the sliding in of the pipes, and so these thermometers probably have to be installed / strapped to the pipe once a pipe has been slid through the front wall.

  These thermometers are so cheap that three different thermometers could be installed in the same pipe, such that the sensors were 1/4, 1/2 and 3/4 of the way back across the bin. It would then be possible to monitor how evenly the decomposition was occurring, as even temperatures would indicate consistency while great differences might suggest that something was not ideal.

  The second of these two electronic components is a humidity sensor. Only one of them is probably needed, for the very center of the pile.

• Stirrers. From time to time, it is beneficial to stir up or "turn" a decomposing pile. In a normal compost pile, that is quite important because all the really effective composting occurs at the very center of the pile where it is hottest. It may not be as important, or even important at all, with our arrangement, BECAUSE WE MAKE SURE NOT TO LOSE HEAT. In other words, it is realistic that the decomposition may occur very evenly throughout the entire bin, rather than primarily in the very center. If this is true, then turning the pile may be completely unnecessary. However, it makes sense to provide for the need.

  There are many ways this can be provided. One obvious way would be to buy several "Earth augers" which would be installed parallel to those piles, with their end sticking out the front wall. At any point where it was felt that it would be beneficial to turn the pile, a wrench could be used to rotate each auger shaft, which would turn the auger inside the bin.

  Given that this should be a minimal need, it seems that a far more economical approach might make sense. Get several more of the PVC pipe, but drill 1/2" holes through opposite walls, such that a foot-long piece of 1/2" metal rod could be stuck through and secured. The result would be the pipe having 4" long Barbs sticking out from opposite sides of the pipe. If maybe a dozen such rods were securely attached through such a pipe, and the pipe was installed similar to the air pipes discussed above, a pipe wrench on the stub of this pipe sticking out would be able to rotate it, which would force those barbs to stir up the material in the bin.

  Higher-tech and more expensive variations of this are obviously possible. It is tempting to wonder if the air pipes could also handle this duty.

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

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

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

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

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

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

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

You can probably see that there are an immense number of variations possible in using this system!

We 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!

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:

(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.

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.

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.

There have been thousands of research experiments which have shown that virtually all plants grow better, faster and larger in an atmosphere of excess carbon dioxide. For example, Chen, K., G.Q. Hu, and F. Lenz, in 1997, (published in a German Journal) found that strawberry plants (fragraria x ananassa Duch. cv. 'Elsanta') grown in 1995 and 1996 had remarkable improvements in an atmosphere of excess carbon dioxide! For the two-month growth season, those strawberry plants were constantly in atmospheres of 300, 450, 600, 750, and 900 ppm CO₂. (The highest of these was around three times natural concentration, with the first being relatively near natural). They found that flowering and fruit ripening started earlier and lasted longer where the higher carbon dioxide was present. Second blooms generally also developed. Fruit productivity was enhanced by increased pedicel number per plants, fruit setting per pedicel, fruit size, and dry matter content of the fruits. They found that the average fruit yield was (considering the 300 ppm as 100% yield): 450 ppm gave 170%. 600 ppm gave 370%. 750 ppm gave 460%. 900 ppm gave 510% yield!

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!

This seems to suggest that if this discarded carbon-dioxide-rich air is sent into a nearby greenhouse, where the carbon dioxide concentration might be increased to three times natural, maybe five times as much fruit and vegetables might be grown from the same plants!

Note that the carbon-dioxide-rich air provided to the greenhouse is also around 150ºF so that it can even provide natural heating for the greenhouse, reducing the need for artificial heating!

Thousands of other research experiments have been performed regarding a wide range of plants, which have all had similar results. Even crops like wheat and soybeans, and trees like cherry and spruce and white oak, have similar growth benefits.

(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!

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 150ºF to 85ºF 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!

There are also some existing technologies, such as those based on the Seebeck Effect (discovered in 1821) which are thermoelectric generation. Semiconductor materials seem capable of decent potential efficiency levels, even at these very low temperatures, but new research would probably be required.

Summary

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!

So we are figuring that those first thousand people who make these will each have slightly different configurations, or they will have tossed in different organic materials. Some will discover brilliant insights in the process. It may actually turn out to be a wonderful thing if some bacon grease is included, or food scraps, or a small amount of used motor oil! No one will really know until someone tries such things! If this sounds potentially exciting, I think it is, because if YOU happen onto some awesome variation, this site can enable millions of others to also benefit from it!

Footnotes

Such a Huge Amount of Free Energy?

The 170,000,000 Btus of chemical energy is simply sitting there! It no longer has any function regarding the biological operation or development of the living plants of which it used to be part. It is simply sitting there, as the organic materials are waiting to (slowly) NATURALLY decompose, which releases all that chemical binding energy as heat energy. It can be equally accurately described as 67,000 horsepower-hours of (heat) energy or 50,000 kilowatt-hours (again, of heat energy). They all mean the same thing. They are NOT mechanical energy or electrical energy, or even heat energy, but rather a potential energy of the chemical binding energies of the atoms in the complex carbohydrate molecules in organic materials. However, Newton told us that Energy must be Conserved, that is that such energy cannot simply disappear. It MUST continue to exist, but it can be changed in form from one type of energy to another, as long as the total energy does not change. All REAL processes do not have perfect efficiency when changing from one form to another, where all the energy that might appear to be lost had simply been converted to heat energy, possibly as frictional losses or radiation or convention losses.

In this case, that 67,000 horsepower-hours of energy gets released very gradually and slowly, spread out over that entire one acre area. But still, during that six-month period (4,400 hours), there is an average of over 15 horsepower continuously released, although it occurs very irregularly in reality. That can also be described as being an average of around 11 kilowatts for that entire six month period! This seems impossible since no one has ever noticed it! After all, we don't have to run across the yard in winter because it is so hot!

We can see why this is the case if we consider it as the 170 million Btus of energy. Again, this is released over 4,400 hours, so we would have an average of around 39,000 Btu/hour. Keep in mind that this is normally spread out over the area of an acre, or 43,560 square feet. This is therefore around 0.9 Btu per square foot per hour, a rather small amount when we stick space heaters under our desks which produce 5,000 Btu/hr! Is there any wonder that no one has ever noticed a heat source which is less than 1/5000 of that of a lowly electric space heater?

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 125ºF to 150ºF. 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 170ºF to 180ºF, 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.

For the record, the first Footnote in the first Global Warming presentation of this series discusses that around 893 watts of incoming sunlight arrives at each square meter of area (due to the Solar Constant and the Earth's Albedo). Our one acre is around 4010 square meters, so the acre can receive a total of around 3.6 * 10⁶ watts of sunlight. Due to day and night and other geometric effects, the actual daily average is 1/4 of this or 9.0 * 10⁵ watts. Multiplying by 86400 seconds in a 24-hour day, this is 7.7 * 10¹⁰ watt-seconds, or 2.15 * 10⁷ watt-hours each day. If we consider a growing season in the middle US to be half a year or 182 days, that means that roughly 3.9 * 10⁶ kilowatt-hours (kWh) of sunlight energy had arrived on that acre during a single growing season.

We have just determined that the actual plant growth absorbs around 50,000 kWh of energy into the chemical binding energy of the organic molecules. We have just mathematically confirmed that the photosynthesis process has around 1% overall thermal efficiency (50,000 / 3.9 * 10⁶). The second Footnote in our second Global Warming presentation provides the complete analysis of where all the thermal efficiency losses are in the natural photosynthesis process.

A VERY Technical Footnote

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 60ºF. 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 / (T^0.5)) + (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):

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 120ºF or 108 * 0.885 or 95.6 Btu of energy at 140ºF. 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:

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 253ºF, 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 204ºF.

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 150ºF 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 150ºF 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 250ºF. 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.

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 + 6O₂ 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.

We note that the "high performance" version of this system (Version 3a, the tumbling one) produces an easy 45,000 Btu/hr to heat a home and has experimentally shown to produce about double that, around 90,000 Btu/hr. We also note that 2,544 Btu/hr is the same as one horsepower of power. See where this is going? That fairly simple unit can CONSTANTLY produce around 45,000 / 2,544 or over 17 horsepower! And it has been shown to produce over 35 horsepower. Granted that it is as simple heat and not as mechanical power. But given that we have millions of active minds in our country, maybe someone can figure out a way to EFFICIENTLY convert that "low grade heat" into mechanical power???

So, just before bedtime, you take your car to a store to get a "bin" filled with bales of a high-performance variation of this decomposing material. Noting that we have already done some experiments with standard mowed lawn grass, where just 24 hours after being cut, it was already impressively producing heat from bacterial decomposition, say that someone discovers even faster ways to get this process rolling. So you get your (5?) compressed bales of this organic material of maybe 200 pounds total weight. We learned above that each pound of the organic material contains at least 8,000 Btu of chemical energy in it, so we are talking 1.6 million Btus of chemical energy total (in a fairly small bin). For comparison, a gallon of gasoline contains around 126,000 Btu of chemical energy, so we are talking here of the equivalent of around 13 gallons of gasoline. Starting to see why thing seems interesting?

It really does NOT seem to be much of a stretch to think that the 200 pounds of material that you put in your bin might be able to completely decompose in say, 12 hours. After all, in-vessel composting already nearly accomplishes that, certainly in 24 to 48 hours! So we would have 200 pounds of material decomposing in 12 hours which is about 17 pounds per hour. That is around 155,000 Btu/hr or the equivalent to 61 horsepower. That may not represent sports car type of power, and it would tremendously depend on whether an efficient way to convert that heat energy into mechanical energy could be found, but we are here discussing driving for 12 hours, at highway speed, (where a medium sized vehicle generally requires around 40 horsepower (mechanical) to push its way through the air and against tire friction), all potentially from a bin full of cut lawn grass???

Yes, a bin that can hold 200 pounds of this stuff would be much larger than a car's gas tank, but still! This is an approach that involves NO FOSSIL FUELS and therefore no global warming effects! AND there would certainly be that delay of some hours while the rather slow decomposition process was working, to build up enough stored energy for you to actually drive somewhere the next morning!

Now, it may not be possible to actually DO this! During that night while you slept, it would be necessary for the bacteria to totally go berserk in generating heat, and then somehow that heat would have to be captured and saved for when you wanted to drive somewhere. Could anyone find some very unusual bacteria that could work that fast? Or, could some really ideal mixture of decomposing materials be found where the effect is fast enough? Like in a compressed, Swiss-cheese structure where oxygen could get everywhere fast enough? Could someone find some way to efficiently collect and save and store that much heat? Hard to say! But it certainly seems like an interesting idea to think about! IF someone actually comes up with something like that, EVERY vehicle on the planet would soon be built to use that method. Somebody probably has an opportunity to get fairly famous!

As to capturing and storing the heat, we mentioned above the Seebeck Effect and the possibility of a low pressure steam engine as being possible ways to produce some amount of electricity from this general effect. Neither of those is probably able to convert more than a few percent of the heat generated into electricity, though, so the idea of using electrical batteries might be a non-starter. But there are an immense number of very creative people out there (maybe including YOU) and someone might find a way to accomplish this process!

By the way, such an approach would almost certainly completely end the problem of smog in cities, and NO_x pollution would also no longer occur.

However, it IS true that no present technology is remotely efficient at capturing low-grade heat to convert it into electricity. But it sure seems to me to be worth giving a lot of thought to!

The house-heating and hot water heating work great, and they have extremely high overall efficiency. That might NOT be possible with the idea of trying to convert that low-grade heat energy into either electricity or motive power. The reason is that there is something called the Carnot Cycle Efficiency, which is believed to always apply to all "thermal processes". Unfortunately, low-grade heat sources have extremely low Carnot Efficiencies (around 11% for this situation). This situation may therefore NOT allow the "efficient conversion" of those 40 or 60 horsepower of thermal energy discussed above into other forms of energy. But, the incentive seems to be there, so maybe someone can find some method of conversion that does not have the Carnot Cycle limitations. Note that the Carnot Cycle is actually a statement of the Second Law of Thermodynamics, which should indicate that it is very reliably true! A vehicle propulsion system where only 4 to 6 horsepower would be available might not be very attractive! But an electricity generation system which converted 11% of 13 kilowatts would provide a family with a constant supply of around 1.4 kilowatts of electric power, 24 hours each day, which DOES seem very attractive, even complying with Carnot Cycle Efficiency. Better yet, the remaining 89% of that low-grade heat energy could probably then still go to heating the home and domestic hot water. An interesting possibility!

The Earth's Rotation as a Source for Energy
Waste Nuclear Power For Making Electricity And Heat?
The Physics of Efficiency In Electric Power Plants
Individual Ways of Reducing Your Energy Usage
Methods of Storing Energy for Later
How Much Energy Comes From the Sun? And Why is there Global Warming?
How does the Sun create so much energy?
Inventions Which Might Help Deal With Coming Energy Catastrophes
An Invention to Efficiently Make Electricity from Solar
Enormous Heating of the Atmosphere by the Alaska Pipeline
Air Conditioning without Huge Electric Bills and without Freon
A Method of Storing Summer Heat to (Nearly) Entirely Heat a House all Winter
An Extremely Highly-Efficient (and Fast, 200.0 mph) Transportation System for People and Products
The Sophisticated Woodstove I Invented in 1973

The Physics of Wood as a Heating Fuel
Why is the North Pole Heating Faster than the rest of the Earth?
A Possible way to greatly reduce Aerodynamic Drag of Airplanes

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C Johnson, Physicist, Physics Degree from Univ of Chicago