Artwork provided by Niranjan Boteju
MOST of the needs of human survival and of some level of happiness can be provided by these various systems. Given that the economy figures to become even more dreadful than now (early 2009), these systems may turn out to become extremely important in coming years. For several years, I have strongly felt that by 2012, the American and most European economies will be in desperate shape, where the Great Depression of the 1930s might be seen as not really having been too bad! Most of these concepts are also applicable to Third World remote locations, so a jungle village in equatorial Africa could use these systems to have reliable food refrigeration and freezing, reliable safe water supplies, comfortable building cooling, substantial supplies of electricity for a wide variety of uses, and even medical sterilization regarding health issues. Even aspects of enabling a small greenhouse to produce five times the amount of food, at extremely high quality, is in the realm (using the HG 3a).
Additional personal opinions: Whether the news of the day has to do with air or water pollution or global warming or dwindling fossil fuel energy supplies, it seems that every week, some company shows up with some idea where they expect to be given billions of dollars of profits. We had seen solar and wind be heavily promoted in the early 1980s and then quickly fade when they did not perform up to the claims; and electric vehicles did the same in the 1990s. More recently, everyone was agog over Ethanol, where the US gave up 1/3 of its entire cropland to grow corn to be processed into Ethanol. No one seemed to be aware that the MOST that crazy (and VERY expensive to the government) effort accomplished was to replace around 5% of the gasoline we use each year! And we hear that Hydrogen is going to be the ultimate solution for energy. But no one seems to recognize that Hydrogen does NOT contain any natural energy on its own - it must be GIVEN that energy from processes such as electrolysis of water. At best, Hydrogen is actually no better than batteries, which also must be re-charged regularly.
The biggest aspect of this is the scale of our usage of fossil fuels. An anecdote seems to show this well. Sir Richard Branson made many press conferences where he promised to remove all the carbon dioxide from the atmosphere that we (including his Virgin Airlines) put into the atmosphere. And he and others have shown small-scale demos of any of over two hundred different chemical processes we already know about to extract carbon dioxide. And everyone celebrates when ten pounds of carbon dioxide gets removed. Fine. But at some point, the SCALE of the problem must be faced! Say that someone actually sets up such an operation (the Solvay Process appears to be the best chance, and it is well proven over the past 150 years). No one mentions that if you do the math, you quickly find that you would have to chemically process 200,000,000,000 pounds of carbon dioxide EVERY DAY, and convert it all into either compressed CO2 gas or some other chemicals. These materials then would have to be HAULED to wherever they were going to be dumped, which would require TENS OF MILLIONS OF LOADED SEMI TRUCKS carrying the waste products! Wanna guess at how much extra Diesel fuel would be required, and the cost of those millions of drivers and trucks which would forever be forced to repeat that every day?
The point being, each week's news reports of magical solutions, always leave out massively important facts, generally related to the SCALE of the whole works. A few companies are getting extremely rich because they manufacture wind turbine blades, wind turbines, and wind turbine towers, but amazingly enough, no one seems to have ever done any actual calculations, or confirmed any actual performance, to see whether such tower windmills could ever provide significant solutions. The reality turns out to be that around 5,000 giant tower windmills would have to be reliably operating to provide just ONE GigaWatt of electricity. So IF it is seriously considered for the US to build around 1,300,000 tower windmills (at at least $15 million each), yes, a reasonable attempt at replacing the coal used in the US to produce electricity could be possible. But each of those tower windmills contains around 800 moving parts in them, meaning that more than a billion moving parts would constantly be wearing out and failing and needing to be repaired at the top of 250-foot tall towers! Do you seriously think that is PRACTICAL?
The USA had used up all the Uranium it had during the Cold War, and by around 1992, all 39 Uranium mines in the US had closed due to lack of available Uranium! Ever since then, we have had to IMPORT virtually all the Uranium we use in our electric powerplants! Have you noticed that NO ONE has ever told you about that? Fortunately, Australia and Canada have been selling us Uranium, but even those supplies are getting used up. And the old reliable hydroelectric dams are getting near the ends of their useful lives. The 700 foot tall Glen Canyon Dam (in Arizona) already has frightening amounts of water leaking AROUND IT through the sandstones of the region. This is weakening the attachment of the dam, and a true catastrophe seems soon to occur. The enormous reservoirs of those dams have been filling with sediment for decades, and they have far less capacity than they used to have.
I have studied these matters for more than 20 years and I see NONE of them as being realistic supplies of energy beyond maybe the year 2020. And so I have attempted to consider other energy related ideas. Here are the few which I think might have a realistic chance of being a LARGE-SCALE solution regarding energy needs:
OK. That is NOT on the scale of National energy consumption, but maybe much larger ponds could use this Tidal Energy for greater performance.
The friction in the culverts should be minimal as the water flow would be very slow, just 10 miles over a six hour period, less than half of walking speed. Energy conversion methods are not particularly efficient, but even if only 50% could be captured, that would still be around 22 kWh of electric energy captured and converted to electricity, in that six hour period. It would occur again around 13 hours later, so around 40 kWh of electric energy might be available from such a system.
There ARE two serious disadvantages to this idea! One is that salt corrodes concrete and salt deposits might also accumulate inside the culverts. The other is that this method would be intermittent, only providing maximum electricity for about 3 hours out of each 13 hours. STILL, it would be rather cheap to install, where extremely few moving parts could ever fail!
It would be wonderful if the products were actually likely to be able to do that! But it RARELY actually occurs! It seems likely that SOME DAY those claims may be credible, like twenty or fifty years from now. But for now, there is IMMENSE "optimism" involved! The companies that manufacture such things always do their "official tests" under absolutely perfect conditions. If it is solar, that means perfectly clear weather, exactly at noon, pretty near June 21 when the Sun is highest, wind blocked, and with all other conditions carefully controlled. So, when they advertise "can produce 7 watts per square foot", that is technically and legally true. However, when actual weather is added into the equation, and the fact that the Sun is NOT at that maximum height except for a few minutes on one day each year, and many losses, the REAL yearly performance that people experience is often 1/10 of what salespeople generally try to promote. As far as I am concerned, that is outright deception, as it is the basis on which rather expensive products and systems are being sold. Yes, they are VERY careful to have done those very specific tests so they can minimize losing lawsuits, but beyond that, they generally seem to have just discovered some types of products where customers seem willing to pay out enormous amounts of money based solely on what a salesperson says! They see it as a gold mine! Didn't a lot of people travel around a hundred years ago selling Snake Oil as the answer to absolutely every malady? Isn't there sort of a similarity? That Manufacturers and Salespeople should at least TRY to be honest with customers? Where is THAT today?
There are separate web-pages on photovoltaic cells and on wind power in this Domain, linked at the end of this presentation, if you should want to better understand the actual Physics behind what ACTUALLY occurs. Since I am a scientist, and not trying to sell you anything, I have no reason to either puff up or denigrate any technologies. Yes, the text below mentions the JUCA woodstoves which I invented in 1973 and which even now keep around 100,000 Americans warm every winter. But I really do not care if you or anyone else BUYS those products (and actually never really did care!). They just happen to operate far better than any other things that have been sold. I suppose that is a bias of sorts, so DON'T BUY ONE. THERE! My interest in ALL these pages is simply to try to provide you with sufficient information where you might spend your money wisely, whatever you choose to buy!
AND, if you are patient enough to be prepared to wait twenty to fifty years, I suspect you might then be really pleased with a wide range of solar and wind products then manufactured and sold, except maybe with the costs involved!
In my opinion, most major purchases need to meet certain requirements regarding AMORTIZING their own cost. That is, they need to show me that they have a realistic chance of actually saving enough eventually so that they will likely eventually pay off their own cost. Only then could any of them be considered as ways to actually SAVE people money, where they could ever be seen as a way of actually saving any money on energy needs! When someone spends $12,000 for a wind-turbine, and another $3,000 for a tower for it, my first thought has to do with how long it is likely to last and how much maintenance it will require. For discussion sake, say that it was likely to last about 20 years (relatively unlikely, as very few of the wind-turbines sold in the 1980s are still working), and that it was designed and built so well that ZERO maintenance was needed in those 20 years.
Thought: You could place that $15,000 in a Savings Account and earn maybe 5% interest over those 20 years, which would result in your then having $39,800 in the bank.
If you are an average family, you have monthly electric bills of between $50 and $100 per month, or $600 to $1200 per year. In 20 years, you would spend between $12,000 and $24,000 for electricity. Yes, the cost of electricity WILL go up, but unless the wind-turbine will supply you at least $39,800 of electricity (and it clearly would not, since you will not USE that much in those 20 years, even with no maintenance and perfect operation for 20 years), it will never even pay for ITSELF, much less actually save you any money!
See the general approach to trying to figure out whether such things are worth buying?
This applies to Electric Cars or Hybrids or Wind-Turbines or Solar Concentrating Collectors or Solar Flat Panels and any future devices that will claim to use Hydrogen. Even woodstoves!
How about the guy in Maine that constantly gets massive media attention regarding his "all solar" house? He freely admits that he paid over $50,000 for the equipment on his roof. He even says that he got special deals on that equipment and that it normally would have cost twice that, or $100,000! Reporters always visit DURING THE DAYTIME, AROUND NOON, IN THE SUMMER, and WHEN IT IS SUNNY, so they see the system providing all the electricity his house needs (at that moment), and even a little extra which he can sell to the electric company. However, even on such a sunny day, around 3/4 of the hours of the day are when the Sun is down or too low in the sky, or in the wrong part of the sky, to be of much benefit. And, unfortunately, we only NEED to have lots of lights on AT NIGHT, when no Solar is being collected. So, all night, even his famous house needs to buy electricity from the power company. Since he is a very environment-aware person, clearly he does not leave lots of lights on in rooms that are unoccupied! And the net result, FOR HIM, is that over a summer month, he generally does not pay for electricity he uses.
Again, superficially, that seems incredibly impressive. However, his situation is much like the one discussed above, where during the expected lifetime of the solar panels, there is NO chance that his initial costs will ever amortize themselves. He even admits that, in telling reporters that his system will never actually pay for itself. But I wonder if his aggressive promoting of that approach doesn't mislead others into buying many thousands of dollars of solar equipment, under the impression that they are going to "save lots of money!"
I have not seen any reference to the actual total area of solar PV panels he has on his roof, but it may be around 2,000 square feet. That would mean that the PV panels could realistically produce around 14,000 watts in the hour around noon on a very sunny day. The weather is never that perfect, except possibly in the desert, so the Maine cloudiness factor must be included, and we are down to around an AVERAGE 5,000 watts in that hour, or around 12 to 15 kWh of electricity in that entire sunny day (after geometrical and other losses). Converting this to AC electricity which is acceptable to the local power company is not easy, and involves some very expensive equipment. But say that NO electricity is used at all in the house in a 24 hour period, and all the electricity created would be sold to the Electric Company. Yes, you BUY electricity for around 15 cents per kWh, but the Electric Company subtracts off several expenses, and you are not likely to even receive 10 cents per kWh for each of those 12 kWh that you could sell them. That's a buck twenty you could make on that sunny day. Would that really merit the giant smug smile of "independence"?
You might note that at a MAXIMUM of selling $1.20 of electricity on really sunny days, you might realistically be able to sell a MAXIMUM of around $200 of electricity in a year. So then how many years will it take before that guy in Maine amortizes $100,000 worth of solar panels on his roof? Ans: Around 500 years, if everything worked really well and nothing ever broke down! Duhhh???
I actually FULLY support such houses, as EXPERIMENTS! And I think it is wonderful that he is NOT causing massive global warming caused at the electric powerplant. Those things are fine! It is only the "misleading others into being receptive to things that salespeople are ready to tell them to sell expensive equipment," which bothers me!
If you have explored the energy-related pages in this Domain, you probably have noticed that most take a "blue-collar" approach to most things, of discussing LOW-COST approaches to such subjects. Also, low-tech approaches to solving such needs. This is the case here, where a VERY practical electrical supply approach is presented, which actually allows you to live a pretty normal life! The people who are now off-the-grid have to constantly be aware of whether it is sunny or not, regarding whether they can turn on a light bulb! They tend to have an ACTUAL available electricity supply of maybe 250 watts to 400 watts (IF they spent a lot for the equipment!) So they could NEVER consider using a vacuum cleaner or a toaster or a hair-dryer that uses 1500 watts or so! I propose a "better approach" here, and it is also generally FAR less expensive!
This seems to suggest a REALLY simple idea! Consider getting TEN standard car batteries (for around $500 total cost, and maybe less if they give you a quantity discount, or far less if you get used ones.) and connecting them IN SERIES. You would then have a supply of 120 volt DC electricity. Better, a HUGE supply of it! Most car batteries are rated at being able to provide 500 amperes for a short time (to start a car) and around 90 ampere-hours total actual energy capacity. This means that each could supply a continuous 30 amperes for 3 hours before the batteries were drained! Being wired in series like that we would have a supply of around 90 ampere-hours times ten batteries total of 120 volts, or in other words 11,000 watt-hours (or 11 kWh) of available electricity.
That is an impressive amount of available electricity!
Given that our normal family modern-lifestyle use averages only between 1,000 watts and 2,000 watts in the evening hours and far less during other hours, we are talking about having LOADS of electricity with this battery approach! I am talking about a MODERN life style, where kids forget and leave lights on in rooms and all the rest. So you are looking at an electric supply system that can provide ALL the electricity your (NORMAL) life requires for something like 24 straight hours before being drained! And you CAN use things like the kitchen toaster (which operates for such a short time that it uses so little electricity from those batteries as to have virtually no effect whatever!)
A SINGLE car battery contains a LOT of energy in it, enough to start your car engine! Ten batteries contain ten times that amount of energy. Basically, a family could have massive Christmas decorations or operate a buzz-box welder, in other words, have no realistic limitations regarding using electricity!
By the way, the US government makes it relatively difficult to obtain ten USED batteries! Companies that sell new batteries wind up having lots of used-but-fine-for-our-purposes batteries which they then have to dispose of. They are not ALLOWED to sell you or give you any of those batteries! Politicians feel that used batteries are too dangerous to have around and so strict laws were passed to make sure that they are all given to companies that make a fortune in recycling the lead in them! I have discovered that obtaining used batteries is not easy because of this, although I do not see the logic in having to buy 10 brand new batteries when their capability is not necessary. It has been suggested that junkyards wind up having a lot of batteries that they hate to have to pay to dispose of! Hard to say the quality of the batteries from a junkyard, but they should be very cheap!
You can estimate your current usage in other ways. Say your monthly bill is around $60, which means that your daily bill would be around $2. Part of the bill is for other things, so if your electricity rate is 15 cents per kilowatt-hour, this suggests that your (wasteful) daily usage might be around 10 kWh. This is comparable to the 12 kWh that we indicated available from the ten batteries, which confirms that we really DO have an electricity source that can realistically support a modern lifestyle for a family, without having to do Abraham Lincoln type reading by a candle! And even THAT level of usage is assuming that no re-charging was going on at all during the entire day!
(For all the devices that require AC current, you could buy an INVERTER, a device that takes DC current and converts it into AC current. The important point here is that you would have LOADS of available electricity to drive all your TVs and computers and refrigerator and hair-dryers and microwaves and all the rest!)
People who attempt to go off-grid tend to worry about using even 20 watts for a few minutes, and they rarely have more than one or two small lights on at any time. I am talking about being able to have a HUGE Christmas light display, for the hours from dusk to bedtime, every day!
Of course, you would have to be able to CHARGE those ten batteries! This is a bigger issue than it might first seem!
Since one horsepower is equal to about 746 watts, our daily use of 10 kWh to 15 kWh of electricity means that we used up about 13 to 20 horsepower-hours of electrical energy. This is a LOT, and it takes a SERIOUS effort to try to recharge that much electricity!
You COULD try to use photovoltaics to do that, although in my opinion, they provide a pitiful amount of electricity. IF you are going to seriously consider buying many thousands of dollars of them, find someone NOT working for that company who has used them for at least a year, to find out how much electricity they REALISTICALLY are able to use from the solar cells. You may be surprised. IF you had a waterfall or river nearby, you COULD build something to get electricity from a crude hydroelectric setup. But my favorite approach is to simply get a bunch (10) of discarded 55-gallon drums and an equal number of old car alternators (I prefer GM). You probably need to buy a single sheet of top quality exterior or marine grade 3/4" plywood (to make very large wooden pulleys!). Each setup will charge just one of the batteries.
So you cut ten of the drums in half, and make ten simple Savonius rotor wind turbines. In a 10.7 mph wind (the average here in the Chicago area) (that is around 16 feet per second), that Savonius rotates at around 3 times each second (with no load) and around 2 rps with a decent load. That is 120 rpm. The car alternator has a pulley on it that is about 2" to 3" in diameter. SO, if you cut a circle out of that plywood which is maybe 20" in diameter, and make the appropriate groove in the outer edge for a standard car fan belt to fit, you have essentially made a large wooden pulley to drive a fan belt, and you can then simply and easily cause the alternator to spin at 7 to 10 times as fast, that is 840 rpm or 1200 rpm. Most alternators can produce most of their power at those speeds.
Long ago, Rankine found that undisturbed wind contains power
from kinetic energy (energy flux) equal to:
E = 0.5 * r * V3
* (area exposed to the wind).
Note that this is a simple application of the kinetic energy definition. r is the air density or 0.00237 lbf * sec2/ft4.
For the 16 fps average wind discussed above, and for a standard 55-gallon drum Savonius, we have 0.5 * .00237 * 163 * 10 square feet or about 50 ft-lb/sec. Since one horsepower is 550 ft-lb/second, this is therefore about 1/11 horsepower, as shown in the wind page analysis. We also learned there that the Savonius only has an efficiency of around 14%, so we really are only getting around 7 ft-lb/sec available to the alternator. That turns out to then be about 1/80 horsepower, or roughly 10 watts. So with a single simple Savonius made from an old 55-gallon drum, in an average wind, we can expect under one ampere of power to try to charge each of the batteries.
(A momentary aside here! You have heard friends brag about their "about to go off-the-grid and about to be making 2,000 watts continuously or 5,000 watts continuously from some sort of wind turbine that a salesperson has told them about! In our wind-energy page, we did the calculations that show that a LARGE farm windmill, 10 feet in diameter, at its higher efficiency of around 30%, can only create about 120 watts of mechanical rotational power! When people repeat what salespeople tell them about 2,000 watts or 5,000 watts, they have no idea how unrealistic that is! Except in a hurricane, yes, that would probably be true!)
Our 7 ft-lb/second from our little (and cheap) Savonius is around 1/80 horsepower, or around 9 watts of power. The belt and the alternator have mechanical losses, so 6 watts of actual electricity is pretty realistic for our 10.7 mph average windspeed. SO, we have TEN of these Savonius/alternator setups spread out in a yard or field, each connected so that it charges ONE of the ten batteries. This is rather slow charging, granted, about the equivalent to a trickle charger, around half an ampere of charging current. (Sadly, that total charging rate, of half an ampere at 120 volts or 60 watts, which is 24 hours a day when the wind is blowing, is actually comparable to the DAILY AVERAGE charging of even fairly expensive solar PV roof panel charging systems.) Because the GM alternators have voltage regulators built into them, they can merrily spin or not spin and always gradually be trickle-charging each of the ten batteries.
(Some of this was invented and built around 1974 and improved around 1998. Other approaches have been more recent.)
IF you insist on seeing impressive claims, we could have given performance for when there happens to be a 40-mph wind blowing near you. Yes, that happens, and salespeople seem ready to use things like that as an example. Because wind carries power at the third-power of the speed, when we nearly quadruple the windspeed, we then are working with wind that has more than 50 times as much power (43 is 64) in it. So we could have been discussing here charging currents of 25 amperes for each battery rather than just a half an ampere. And then we could be saying 25 amperes times 12 or 14 volts times ten alternators and we could be puffing about producing 3,500 watts of power being produced continuously. Sure, as long as the wind keeps going at 40 mph!
Now, getting back to reality!
Keeping in mind the massive electrical storage those ten batteries can have, you can merrily use up electricity as we are now all used to doing! You could certainly use a standard kitchen bread toaster! I suppose you could even use an electric heater (1500 watts, around 5,000 Btus of heating) if you wished! But the chargers have to eventually give the batteries back the same amount of electricity. At 0.5 ampere charging current, it could take quite a while if you seriously deplete the batteries by very heavy use!
If you have a lot of space available, and a lot of scrap drums, you could make more Savonius rotor assemblies! If you made FOUR for each battery, then everything would charge at 2 amps, about 250 watts nearly continuously. In one average day, you could then charge the batteries with 24 * 250 or 6,000 watt-hours or 6 kWh. Our modern life, with all of our appliances, generally uses up around double that. SO, if you would want an ABSOLUTE NORMAL usage / wastage of electricity as we now do, where we use up around 12 kWh per day, all you need to do is make EIGHT Savonius rotors for each of the ten batteries! You probably would even have EXTRA electricity that you could share with neighbors! (In general, you have to figure that neighbors would NOT be pleased with your yard! When they would see 80 ugly spinning old drums in your yard, it will be difficult for you to convince them that it is really just modern art!
People who try to be "off the grid" tend to only have one or two small lights on at any time. What we are talking about here is having the house blazing bright, and probably even covered by a gaudy Christmas display in that season!
Note that all this is FAR less expensive than the $10,000 or more that you probably would need to spend for a pitifully inadequate bought photovoltaic or wind-charger system, and it performs easily ten times better! However, if you have close neighbors, they probably would not appreciate looking out and seeing 80 Savonius rotors always spinning! Worse, if you economize by not actually using any bearings, they sometimes squeak when they rotate (like some rooftop ventilating fans do).
If you use GM car alternators, they each already have built in a voltage regulator, which keeps it from over-charging the battery, so the alternator can simply be directly connected to the battery. As to finding enough scrap drums and alternators, that would be up to you!
Obviously, it would be possible to BUILD Savonius Rotors that were larger, say 3 times taller and 3 times wider, so that a single rotor could provide all the electricity for one battery. THEN you would only have ten of these buggers in your yard! Notice that the single car alternator still has massive extra capacity. We would still be only charging at around 4 amperes (the equivalent of eight of the 0.5 amp drum-versions), and car alternators are generally rated at around 60 amperes. Yes, when you have a storm and 30 mph winds, where (27 * 4) 108 amperes of charging could be available, you would be limited to the 60 amperes that the alternator would allow, but that really only means that you could turn on even MORE lights when it is stormy!
There is one further issue to consider. Say that one of the Savonius rotors seizes up or falls over, or a belt breaks or falls off, or an alternator fails. It would be good if you could know that! Otherwise, ONE of your batteries might no longer be charged and might completely get drained. However, there are really simple solutions to this! One of the very simplest is to get 10 electronic resistors of 100K value. Wire them in series, and across the entire 120 volt DC output of your system. Connect a wire from each wire between batteries to the same wire between resistors. Add sensors, voltmeters, or assorted other things to monitor the voltages between each pair of resistors. As long as everything was working right, the voltages should always stay very close to 0, 12, 24, 36, 48, 60, etc. IF any of the voltages got more than a volt away from those known values, you would know that something was wrong in a battery, alternator or rotor. Simple, cheap and easy.
These comments have been focused on Savonius rotors made of old 55-gallon drums, because they are so dirt cheap and quick and easy to make. (See the WIND presentation in this Domain for detailed information.) But solar IS possible, especially if and when solar PV panels get a lot cheaper and a lot more efficient. Also, if you have either a waterfall or a consistently flowing creek or river accessible, that energy could also provide the power to drive the alternators. If you have an outdoor wood-fired boiler, it could produce steam to drive small turbines to drive the alternators. If you approach this all creatively, you can find good solutions to nearly anything!
Personally, I like the idea of making an INDEPENDENT set of wiring inside the house for 120 volt DC. The same SIZE of wire, 14 gauge or 12 gauge, is fine, but I recommend getting some different color wire, such as pink or blue so no one would ever confuse it with the house's 110 AC wiring! Each room could have two separate ceiling lights, possibly in a single device, one being a bulb that was supplied by 110 AC and the other bulb that was supplied by the 120 DC. Wiring the light switches might be an adventure, but certainly easily solved.
It is a variation of the residential-scale Savonius Rotor approach, but with several sophistications added in for greater performance. And also built on a far larger scale!
It turns out that the NORMAL wind (at around 10 mph speed) that passes through one square foot of area contains about 5.0 Watts of mechanical (kinetic) power in it. If through an area 100 feet tall and 2,000 feet wide, and including the effect that windspeeds are higher at higher altitude and that the power in wind is proportional to the CUBE of the windspeed, that area of wind contains around 4.4 megaWatts of wind power. It turns out that by building some large concrete walls, and a few other simple devices, a reliable 1.2 megaWatts of electricity (and usually much more) can be captured from this area of wind. THAT is about the amount of electricity that roughly one thousand modern homes USE NOW!
A local business or bank would need to agree to put up around $1.8 million dollars for construction. Nearly half of that will be paid to about 100 LOCAL construction workers in building the concrete walls! About one-third of the total cost will be spent on buying and trucking in a lot of sand and gravel and Portland Cement with which to mix the concrete (on-site).
At a common cost of electricity today, 15 cents per kiloWatt-hour, that amount of electricity can and will be sold for around $1.7 million EACH YEAR! In a year, or certainly before two full years, the ENTIRE FACILITY would have paid for itself in profits from the electricity produced! (NONE of the giant wind-farms can even say if or when they will ever be able to be a profitable business! And they concede that dependence on many tower windmills will RAISE the cost of electricity a LOT!)
In addition, it turns out that in 1992, the US Government initiated a Program called the Production Tax Credit (PTC) which is now 2.0 cents credit for every kiloWatt-hour produced for the first ten years of operation. Even if all the electricity produced was given away for free, this credit can be about $210,000 for each of the ten years, in other words ENTIRELY paying for the entire $1.8 million construction cost of the whole facility!
In addition, such LOCAL projects in each small town could encourage and inspire local businesses and local banks to again get back into their normal operations! If only 10,000 towns decided to each do this, each hiring 100 construction workers in the process, you might notice that is a MILLION NEW JOBS, all of which are good-paying and full-time! Not bad, eh?
(This was first fully Engineered in 2008)
This system is presented at: http://mb-soft/public/wind7.html
There are many brands of woodstoves which now have decent efficiencies. The older Potbelly and Ben Franklin stoves only had around 25% efficiency, but modern airtight woodstoves are often above 60% efficiency (although they brag about even higher numbers in carefully controlled tests). Unfortunately, the airtight woodstoves have two enormous problems. The first is that by forcing a fire to try to burn without sufficient oxygen, it cannot burn very well and it both tends to create pollution and creosote and also has lower efficiency as a result. The second is that the price of nearly any of the quality airtights is over $3,000, and they are all really tiny products, making it difficult for an owner to ever haul and burn enough wood to even pay for the woodstove! (That amortization thing again raises its head! Partly due to the tiny firebox not being able to burn enough wood to make using it very worthwhile, and partly because the owners tend to stop using it after one winter of enthusiastic use!) Again, the only exception to this that we are aware of is the (NON-airtight) JUCA B-3B/B-3A woodstove, which, since 1973 has an overall seasonal efficiency of around 81%, and which is actually a central furnace which happens to burn wood. However, the JUCA units have a disadvantage in that they all use rather large and powerful blowers to spread the heat throughout a house. That is normally not a disadvantage, except when the electricity for the blower must be generated on-site! The JUCA woodstoves were invented in 1973. (A link to the JUCA web-site is in the links at the end of this presentation.)
Therefore, far better than any of the above is the HeatGreen 3a unit which YOU can build with around $200 of common local materials! (Some day there will be ah HG 4a unit!) This system is unique in NOT having any flame or fire! It allows waste organic materials (cut grass, leaves, weeds, crop residues, etc) to NATURALLY decompose, which happens to release amazing amounts of energy, which this technology then efficiently captures. It still boggles my mind that the cut lawn grass and leaves and other organic residue from a single acre of land ABSORBS around 170,000,000 Btus of sunlight in the process of photosynthesis in making those materials, which then all must be RELEASED because of the Conservation of Energy! So that single acre calmly and quietly releases around 170,000,000 Btus of heat energy during the year, while your house likely only needs a supply of maybe 50,000,000 Btus for the entire winter! Duh? Entirely GREEN, too! (This was invented in 2007) (This system was offered to Europe, the European Union, and the government of the Ukraine in 2007, and then to dozens of leaders in the Ukraine in 2008, although no one then seemed interested in enabling homeowners to keep their houses warm, when the Russian supplies of natural gas were shut off those two times.) Two web-pages are important regarding that device, the first of which explains what it is and why it works, at:
http://mb-soft/public3/globalzk.html
The second contains all the instructions to build one!:
http://mb-soft/public3/globalzl.html
We have yet other non-fossil-fuel approaches to heating a house and its hot water. One is low-tech and the other is higher-tech!
Finally, in a more sophisticated way, and higher-tech, if you do not want to have to carry grass and leaves to put into a HG 3a for heating, there is an alternative, but it is somewhat more expensive to have. It is the NorthWarm whole-house 100% solar heating system. It was invented and fully Engineered in 1978 and 1979. There are two Versions. The first is most efficient, where the house is NEWLY built with the Version 1 system intimately being part of its structure: (We are confident that a Version 1 would be able to ENTIRELY solar heat a home for the entire winter in most locations in the southern half of Alaska, and certainly nearly anywhere else.)
http://mb-soft/solar/index.html
The Version 2 is a more limited variation of Version 1, for EXISTING houses, where a separate two-car-garage-sized out-building must be built and with underground heat tunnels between that structure and the existing house.
http://mb-soft/solar/solar2.html
The Version 1 of the NorthWarm system is so efficient and so effective that it INCLUDES an air conditioning system as part of Version 1! That air conditioning system has been made available to the public (for free) beginning late in 2000, and it is the Free A/C system discussed below.
Say that you have a bedroom which is ten feet square and eight feet tall, a little smaller than average, maybe, but it will be used here for this example. That bedroom therefore has a TOTAL SURFACE AREA of 520 square feet (easily calculated). Now say that you insulated the heck out of the walls, ceiling and floor of that bedroom, to somehow get everything up to R-100 insulation. (Most bedroom walls are not insulated at all, except for the walls that are exterior walls.) (You should note that R-100 takes a LOT of insulation! It is 20" thick of foam insulation, and even thicker fiberglass!) Now say that the average temperature of adjacent rooms is left to cool during the night (unheated, to save money on heating bills) and they drop to around 45ºF during the night. And you like to have your bedroom at a cozy 70ºF, even warmer than most people do. We can calculate the total heat loss of that bedroom from these figures! It is the total surface area times the temperature differential divided by the R-factor of the insulation. In our case, this is 520 * (70 - 45) / 100, which is about 130 Btu/hour.
It turns out that the human body, when asleep, commonly burns up around 80 Calories per hour, which converts to about 320 Btu/hour.
If that bedroom had been absolutely sealed tight, the (one) human body inside it during the night would be GIVING OFF around 320 Btu/hr, while the room was only LOSING around 130 Btu/hr! (due to the incredible levels of insulation installed surrounding it). This is actually the EXACT same reason that a sleeping bag works to keep you warm in any climate!
You can also see that these calculations show that even if the adjacent rooms were at below zero temperatures, that one human body would STILL be able to keep the room as cozy as desired!
There IS a disadvantage in this system! The heating source (the one body) has such low heat output that at the START of a night, the room could take some time to warm up, because the air in the room and all the objects within it must all be warmed up as well. Again, when you FIRST get into a sleeping bag, you can be cold for a minute or two, but then become toasty warm fairly soon. In this case, we need to heat up a LOT more mass of materials to get the whole room warmed! And also, IF a door is opened where really cold air was able to fill the room, it would again require some time before all that air was again heated to the desired temperature.
I have tried this and it works! Amazingly well! But I actually then modified my experiments to involve the equivalent of a canopy bed, where the delay of warmth was then rather minimal in getting the air inside the canopy chamber and the bed warmed, just a few minutes, where then I would loosen the canopy walls once I became toasty in bed, where the room then gradually warmed during the night.
One WONDERFUL aspect of this is that IN THE MORNING, I always woke up to a wonderfully warm bedroom, even though it was technically unheated and even when the outdoor temperature was below zero! LEAVING the cozy bedroom to go to a rather cold kitchen, was a different matter!
Note: It is NOT a good idea to SEAL such a bedroom, because during the night you consume oxygen from the air, and you don't want to cause any situation where you might not have sufficient oxygen in the air you were breathing. In fact, THAT is why we used the parameters we did, where the heat being released by the body is nearly three times what is actually necessary to heat the room, such that a MODERATE amount of air circulation can be allowed through the room. Again, it is NOT a good idea to get ENTIRELY inside a sleeping bag, but to arrange it so that your nose is able to use air which is outside the sleeping bag! Otherwise, you could easily use up too much of the oxygen inside the sleeping bag and possibly have a health emergency result.
So a variant of the HG 3a device is designed to only have enough capability to heat the domestic hot water and not also heat the whole house. The standard HG 3a also has the capability of having a long coil of large diameter water pipe inside it to be able to do both jobs at once.
However, there are MANY ways to try to heat domestic hot water! There are many products sold which try to use solar energy to heat the tank, but they tend to have very minimal effectiveness. They are sort of variants of the black plastic bag you can buy for camping where you hang it to get heated in sunlight so one person can later take a shower. They WORK, but with very limited capability. There are products sold as swimming pool heaters which are similar, and which can have some value, but it is limited.
There are a LOT of ways to heat a MODERATE amount of domestic hot water! Some small tanks have been manufactured and sold to go inside a woodstove or fireplace, which work, but many were poorly designed and they have the capability of bursting due to extreme high steam pressures which can develop in such environments. Such devices must have several safety valves on them to release excessive pressure.
Here is another approach. I have never heard of anyone trying to do this, but it certainly has plenty of capability of heating domestic hot water for a family. It is actually based on an OPPOSITE application of a characteristic of Ideal Gases of what is described below for providing food refrigeration, food freezing, and the earliest (1846) form of building air conditioning. In this case, the SAME device is used. See the animation graphic below of the air conditioning system. It is a simple and cheap Savonius rotor windmill driving a simple large rigid piston in cylinder to MODERATELY COMPRESS natural air, in this case into HALF the volume. The ideal gas laws show that when natural air which starts out at a deep soil 52ºF temperature is COMPRESSED into half its volume, the air HEATS UP to around 215ºF temperature! We picked the deep soil temperature as the LOWEST temperature of available air to draw into the cylinder. If the weather happened to be warmer, then the temperatures would be higher still.
The device for this purpose would NOT have the outlet pipe underground, and indeed, it would need to have very good (R-20 or better) thermal insulation around it. We would WANT it to get up near that 215ºF and to STAY there! So we would now have very hot air inside a long 4" diameter pipe, which has excellent insulation surrounding it. We then put a 3/4" copper tubing inside the middle of that hot air, and send pure water INSIDE that copper pipe. That water would gradually HEAT UP from the extremely hot air surrounding it! Presto, a supply of hot water for any faucet or shower or bathtub!
WHY does this work? Well, you have probably seen an air compressor. The head and block of that compressor has cooling fins all around it, but it still gets so hot that you can burn yourself by touching it. That heat is ENTIRELY due to the air getting hotter as it gets compressed! Specifically, the actual Ideal Gas Law which applies for air when it is being adiabatically compressed, is T2 / T1 = (V1 / V2)0.4. Temperatures and pressures are measured in absolute scales. So you can confirm that if we HALVE the volume, this simple formula shows the 215ºF resulting temperature we mentioned above.
The actual temperature you would get depends on diameter of pipes and if you are using a storage tank and other such things, but the point is that a temp of 215ºF is surprisingly easy to produce, and WITHOUT needing any fire or flame! Down below, we describe how to overcome the effects of the volume of a storage tank and the piping.
The QUANTITY of hot water depends on how long the pipe is and how much copper tubing is inside it. It MIGHT even be possible to combine this water heater with a standard hot water TANK to then have a supply of 40 gallons or whatever of hot water for reliable usage. It also strikes me as possible to have each of the hot water pipes to kitchen and bathroom faucets fed by separate co-axial heater tubes, so that INSTANT hot water would come out of any faucet. (I HATE waiting for the heated water from a tank to have to get to where I am waiting for it!)
It might also be possible to create that heat due to the air compression, use it to heat water up, and THEN send that compressed air down into an underground tube or tank (as described below regarding food refrigeration) and therefore get yet another benefit from the simple device! Cool?
Yet another possibility is to focus on the compression-heating effect to create WARM AIR to try to heat a house! I will probably try that in the process of doing these other things, but I personally doubt that the power that can be captured by a Savonius Rotor would be sufficient enough to do significant heating of a room or house. Heating domestic hot water? Easy! Doing food refrigeration and freezing? Easy. Bigger scale energy needs require greater amounts of energy to start with, per the Conservation of Energy!
When people try to go off-grid, they often do not realize that if they need to have a deep well drilled, the pump then necessary uses a LOT of electricity in raising that water a thousand feet or whatever! On top of that fact is that often the giant trucks that carry the well drilling equipment often cannot get to really remote locations, and huge extra charges are then involved in boring the well in the first place. These systems presented here do not require boring a well or even having a powerful pump. They actually remove humidity from the atmosphere, in amazing quantities!
(This system was invented and Engineered in 2007. We had previously
invented a rather different system to provide pure drinking water
using any source of water, whether it was seawater, graywater,
polluted river water or anything else, in 2004.) (It has been amazing that
UNICEF and OXFAM and the other giant NGOs have had absolutely no
interest in this and the earlier devices for this purpose. When the
Boxing Day Tsunami killed hundreds of thousands of people, and
eliminated safe water supplies for millions more, we and several
similar small companies OFFERED to provide FREE SYSTEMS which could
have immediately been sent to the damaged villages. We (and the other
companies) were told to SELL the equipment we had and then to send
them the money from those sales, so that THEY could then decide to allocate
the money to buy what they, the "experts", decided was needed.
Bureaucracy often drives me crazy, and that was a prime example.
Several of our companies had systems which were ready to be crated
up to be shipped to Indonesia, where the people there would then
have had good access to excellent water within a few days. Instead,
UNICEF and OXFAM bought bottled water from companies in the US for
several dollars per bottle, paid a fortune to ship them around the world
to get there, and then handed them out for a few days, until their supplies
of bottled water ran out. The local people then had NO good
supplies of water for at least a year afterward, and many still
do not, even several years later. Why can't bureaucrats comprehend
common sense?)
http://mb-soft/solar/saving.html
A guideline is the temperature of the deep soil (four feet deep) in any location. There are two easy ways to determine this number. One is by adding the day and night average winter temperatures and the day and night average summer temperatures and dividing by four to get an overall average temperature for that climate. The deep soil will be very near that temperature. The second method is to pump some water up from a well and measure its temperature, which should be close to that same number. If that number is lower than 60ºF (16ºC), the Free A/C should work fine, including removing humidity from the air. If it is up to about 70ºF (21ºC), it can provide moderate cooling but probably no dehumidification, meaning a dehumidifier would be needed OR the Hot Climate device below could be used. If the deep soil is above 70ºF (21ºC), the Hot Climate device will likely be a good idea, although the Free A/C can still PARTIALLY cool down an extremely hot house or room, down to near the deep soil temperature.
That presentation is VERY long and comprehensive, in order to include all the necessary information for understanding the concept and the system and for actually building it for a few hundred dollars total cost. It essentially is a Technologically Engineered version of a natural cave, where summer coolness is natural. However, in the realization that some people have applications that are in peculiar climates or soils or the building is a giant tennis club complex, we made available a Technical Packet of the Engineering data and equations. For that, from the start in November 2000, we have asked that a person give an anonymous $250 to any worthy Charity such as a Soup Kitchen or Homeless Shelter or Food Bank or others. Amazingly, over 5,900 people have requested the Technical Packet so far! Assuming they all gave the requested gifts, that means that as a side effect of this Free A/C, nearly $1,500,000 has been given to needy causes! Cool! In many ways!
Specifically, this drawing is for an EXTREMELY hot climate, where we chose a 4 PSIG pressure differential in order to produce really cool air no matter how hot the air or building or ground is. Because of that relatively high pressure differential and the large amount of cool air needed for air conditioning, this configuration would require a substantial amount of power, from the wind or from a river or waterfall. In a less severe climate, or if less cooling boost is needed for the standard Free A/C, it might be possible to change the crank offset to 1.9" instead of the 3.8" we chose here. That would create a lower pressure differential, around 2 PSIG instead of the 4 PSIG we selected here, and also less air would be processed, making the power need from the Savonius Rotor far less. For a climate where the soil is only moderately warmer than usable for the Free A/C, such a change, or even less yet, might make sense. The basic construction would still be identical.
Artwork provided by Niranjan Boteju
This drawn example pumps about 1.5 cubic feet of air in each stroke, around 50 times per minute, so it would provide about 75 cubic feet of cool air per minute, not a lot but useful, because it can be quite cool. The maximum pressure that this arrangement could produce (due to the ratio of the fraction of the drum volume at max and min, 32.5"/25.75") is around 4 PSIG. When air at that pressure is released to atmospheric pressure, it naturally cools by about 41ºF. On a 120ºF afternoon in India, and the deep soil temperature is 85ºF, this system could fill an underground tank with some slightly compressed air (4 PSIG) which cooled to 85ºF due to contact with the deep soil. When that compressed air gets released (inside a house) that air can cool by an additional 41ºF, and arrive in the house as cool as 44ºF. A modest amount of air that cool might be very beneficial in one or two rooms in a very hot house on a 120ºF afternoon in India!
Notice that this is a RECIRCULATING system, where the house air is re-used over and over. A popular habit in some countries such as India is to use Single-Pass Ventilation, where windows stay open and any cooling effect is immediately discarded, which is extremely wasteful of cooling effect! All advanced Air Conditioning systems recirculate the house air, as does ours. Instead of having to start with outdoor air at 120ºF, it is far easier and more efficient to start with air from inside the house which may only be at 95ºF.
There is an extremely wide range of climates and house sizes for which this system might be used. If you choose to just make something similar to this drawing, it will certainly work, but some Engineering calculations can be useful to make sure to build a system which works GREAT!
Some numbers: The device as drawn processes 1.25 cubic feet of air every second, and compresses that air by 4 PSI or 576 pounds per square foot. Multiplying, we see that 720 ft-lb/sec of mechanical power is involved. This can be converted to 1.3 horsepower or 980 watts of mechanical power. One PSI is equal to about 6900 nt/m2 (or Pascals) and 1.25 cubic feet of air is equal to about 0.0354 m3. Multiplying 0.0354 * 6900 * 4 equals 977 Watts, confirming our numbers. A relatively large Savonius Rotor would need to be built to capture this much wind power. At the other end of the system, we have 75 cfm of air or about 360 pounds of air per hour that is released to capture around 41ºF temperature differential from the house's air. Air has a thermal capacity of about 0.25 Btu/pound. Multiplying, this is around 4,000 Btu/hr of cooling. That is not an enormous amount but it certainly could cool a room or two very well. If the deep soil is cooler than 85ºF, the cooling performance can be much greater.
The local average windspeed determines how much power there is in the wind's motion. You want to make sure that the windmill is powerful enough to compress the air with the winds that are usually around! For example, in the US, a common windspeed is around 10 mph, and that speed wind contains around 5 watts of power per square foot of wind area. This can indicate how LARGE a Savonius rotor or other power source might be necessary. The pressure that the piston has to push against and the area of the 22" piston and the rate at which the piston is moved, determine how much power is used in compressing the air. In the process of compressing that air to this example 4 PSIG, the Ideal Gas Laws show that the air naturally heats up by around 42ºF in temperature, up to about 127ºF. Some additional cooling power is gained by then letting that self-warmed compressed air cool off in the underground pipe and storage tank (down to around 85ºF), and then we have already noted that releasing the pressure causes the air to drop down to around 44ºF in being released inside the house. You can see how it is possible to estimate how much air conditioning effect can be obtained just from some math calculations!
I CHOSE the dimension of the crank offset of about 3.4" to set the 6.8" distance the piston moves back and forth inside the drum cylinder. Note that the drum does NOT have a lid on the back side. I CHOSE the length of the connecting rod to set the RATIO of the two volumes of air inside the drum cylinder (32.6" / 25.75"), to establish the (maximum) PRESSURE created and therefore the added cooling effect when the partially-cooled-by-the-deep-soil compressed air is released into the house. I strongly suggest doing a little simple math if you intend to change any of the dimensions shown here.
Please notice that BOTH of the two large pipes connected (toward the right in the drawing) are ALWAYS underground, in order to gain cooling effects from the deep soil, and both go completely to the house and inside it. The INTAKE pipe draws hot air from INSIDE the house, up near the ceiling, at say 95ºF, which gets cooled to the deep soil temperature of 85ºF in that first (INTAKE) underground pipe. The compression in the drum cylinder causes that air to heat up to around 127ºF. As that self-warmed air passes through the OUTLET underground pipe, it cools back down to around 85ºF again, but it is now compressed. There CAN be some additional benefit of burying a storage tank in that OUTLET pipe near the house, in order to give that air some extra time to cool down to the deep soil, but that can depend on many variables. Once the OUTLET pipe is INSIDE the house, it needs to be controlled by a pressure release valve, which can also be a reduction in diameter of the pipe and a solenoid valve. A wall thermostat could control that solenoid valve to then only release the very cool air when a room called for it.
This hot climate A/C is actually a variant of the Refrigeration and Freezer system discussed below. This modified A/C system was invented in 2008.
Air conditioning is a process that uses up a good deal of power (as you may have noted by the powerful compressor running outside your house which eats up massive amounts of electricity). So the A/C version here is likely to require a larger Savonius Rotor than old 55-gallon drum which is adequate for the refrigeration or freezing usage, is likely not large enough for significant A/C production. Below, we describe how simple changes can be made to change the crank throw and the connecting rod length to greatly change the capacity and performance of this system.
The refrigeration system involves underground tubes, but also some added components that enhance the effects. It is actually based on the first invention of refrigeration around 1844. Some external power is necessary, which is obtained from either a simple and inexpensive Savonius Rotor windmill or from flowing or falling water. Then there is some mechanism that acts as a low pressure air compressor. Here is a drawing of the general arrangement. Many variations are possible.
Artwork provided by Niranjan Boteju
This drawn example, which involves a SMALLER 20-gallon steel drum, pumps about 0.6 cubic feet of air in each stroke, 30 times per minute, so it would provide about 18 cubic feet of cold enough air per minute for usage in a refrigerator. We will consider an example here of deep soil at around 65ºF. The maximum pressure that this arrangement could produce (due to the ratio of the fraction of the drum volume at max and min, 18.6" / 14.7") is around 4 PSIG. When air at that pressure is released to atmospheric pressure, it drops by about 41ºF. No matter what the air temperature or deep soil temperature or house air temperature might be, air that is drawn FROM the refrigerator box should not be above around 40ºF. The deep soil temperature is generally of no use whatever for this INTAKE air as it is already cooler than the deep soil is, as it likely would WARM the air up, just the reverse of what we want! Therefore, we use SMALLER DIAMETER 2" PIPES for this (as compared with the A/C presented above) AND that INTAKE pipe needs to have thermal insulation around it. The compressed air gets released (inside a refrigerator box) and that air can cool by an additional 41ºF. After it is compressed to our 4 PSIG pressure and then cooled by contact with deep soil, the compressed air should get down near 65ºF and then drop by that additional 41ºF due to the expansion, to arrive in the refrigerator as cool as 24ºF. That is cool enough to refrigerate food safely in the 35ºF to 40ºF temperature range.
The PRESSURE needed for the refrigeration is dependent on the SOIL TEMPERATURE. As a guide, if your soil temperature is lower than about 65ºF, 4 PSIG is fine. Up to 75ºF, a longer connecting rod should be used so that a higher pressure of 5 PSIG is created (nothing else needs to be changed). Up to about 85ºF soil temperature, 6 PSIG should be created. The reason for this difference is that the goal is to provide air at around 32ºF, and that requires different amounts of differential cooling down from the deep soil temperature that we have available in a specific location.
In other words, in nearly any location in the US, if you choose to just make something similar to this drawing, to create a max of 4 PSIG, it will certainly work well.
Some numbers: The device as drawn processes 0.6 cubic feet of air per stroke or 0.3 cubic feet every second, and compresses that air by 4 PSI or 576 pounds per square foot. Multiplying, we see that 170 ft-lb/sec of mechanical power is involved. This can be converted to 0.3 horsepower or 230 watts of mechanical power. One PSI is equal to about 6900 nt/m2 (or Pascals) and 0.3 cubic feet of air is equal to about 0.0085 m3. Multiplying 0.0085 * 6900 * 4 equals 234 Watts, confirming our numbers. A relatively common-sized Savonius Rotor could capture this much wind power. At the other end of the system, we have 18 cfm of air or about 85 pounds of air per hour that is released to capture around 41ºF temperature differential from the refrigerator's air. Air has a thermal capacity of about 0.25 Btu/pound. Multiplying, this is around 900 Btu/hr of cooling. That is not an enormous amount but it certainly could cool a refrigerator full of food very well.
The local average windspeed is likely to be sufficient to produce the limited amount of cooling needed inside a refrigerator box, as long as the door of the refrigerator was generally kept closed, so that a crude 55-gallon-drum Savonius Rotor should be sufficient. The pressure that the piston has to push against and the area of the 18" piston and the rate at which the piston is moved is moderate, and those parameters determine how much power is used in compressing the air. In the process of compressing that air to 4 PSIG, the Ideal Gas Laws show that the air heats up by around 42ºF in temperature, up from the initial 40ºF to about 82ºF. This newly-warmed compressed air is then cooled off in the underground pipe and storage tank (down to around the local deep soil temperature, which is 52ºF near Chicago but will be assumed to be 65ºF in this example for a more southerly location). So now we have a supply of air compressed to 4 PSIG which has cooled in the OUTLET pipe (and storage tank, which might be an old hot water heater tank), which is NOT insulated such that it can COOL down to the soil temperature, so the air drops to about the deep soil temperature of 65ºF. We have already noted that releasing the pressure causes the air to drop down by about 41ºF, to around 24ºF, in being released inside the refrigerator box.
I CHOSE the dimension of the crank offset of about two inches to set the 4" distance the piston moves back and forth inside the drum cylinder. Note that the drum does NOT have a lid on the back side. I CHOSE the length of the connecting rod to set the RATIO of the two volumes of air inside the drum cylinder (18.6" / 14.7"), to establish the (maximum) PRESSURE created and therefore the additional cooling effect when the compressed air is released.
Notice that BOTH of the two pipes connected (toward the right in the drawing) are ALWAYS underground and both go completely to the house and inside it. Also that the INTAKE pipe is wrapped with thermal insulation. The INTAKE pipe draws relatively warm air (maybe 40ºF) from INSIDE the upper part of the refrigerator box. The thermal insulation around the INTAKE pipe keeps that somewhat cool air from being heated by the soil which is likely warmer than it is. The compression in the drum cylinder causes that air to self-heat by the 42ºF we have already discussed, up to around 82ºF. As that self-warmed air passes through the OUTLET underground pipe, it cools back down to around 65ºF of the deep soil again, but it is now compressed. There CAN be some additional benefit of burying a storage tank, such as an old hot water heater tank, in that OUTLET pipe near the house, in order to give that air some extra time to cool down to the deep soil temperature, but that need can depend on many variables and many locations will not need it. Once the OUTLET pipe is INSIDE the house, it needs to be controlled by a solenoid valve, which can also be a reduction in diameter of the pipe. The existing temperature thermostat inside the refrigerator could then automatically control that solenoid valve to then only release the very cool (24ºF) air when the refrigerator thermostat called for it.
A common 55-gallon drum Savonius Rotor should be adequate for the refrigeration or freezing usage, for most climates.
For all of these drum-compressor systems, the ACTUAL pressure you will
create will be less than we have calculated! How much less depends
on specifically what you build! Here is why. We used the ratio
of the volume INSIDE the drum under the piston to calculate the
pressure ratio and therefore the maximum final pressure. That is
not actually the case! The OUTLET flapper valve does not actually
separate the volume of the drum from the volume of the pipe connected
to it, including any storage tank you might include, all the way up
to the solenoid valve that can release the air pressure. Fortunately,
there is an extremely simple way to correct for this! You could
INCREASE the dimension of the crank on the Savonius Rotor shaft (and you
will then also have to change the connecting rod length to cause the
RETRACTED position of the piston to be the same as before). These are
simple changes which you could make at a later date if you so decided
that they were necessary. There are only two concerns about doing this.
(1) If you are using a drum which has ridges for structural strength,
you can't have the piston try to pass by such a ridge during its
movement, both for the air leakage which would occur and for mechanical
problems of the piston possibly getting stuck in that groove! (2)
If you use a storage tank that is LARGER in volume than the drum-compressor
is AND you operate it to produce a high pressure, the movements of
the piston might get very extreme.
Note that TWO or more of these systems could feed compressed air into the same buried storage tank and house. Regarding providing Air Conditioning, this might be a simpler solution than in building a giant Savonius and drum-compressor!
For doing the actual calculations, you would need to use ABSOLUTE temperatures, based on -459ºF. Therefore, a deep soil temperature of 65ºF [like for Alabama] can also be described as being 524ºR, in a temperature system based on absolute zero).
You have dug a pit a few feet deep where you have securely mounted the (horizontal) steel drum and also the mounting supports for the Savonius Rotor windmill, completely below the surface of the ground! We create a crude low-pressure air compressor, and can even use a disk of plywood for the piston, which we then surround with weatherstripping to reduce air loss past the piston. Our crude compressor only has two Strokes, Intake and Compression/Exhaust.
You will then simply dig at least one trench to bury maybe 100 feet of the appropriate diameter PVC or metal pipe. (If you are going to do A/C, you may need to dig several [parallel] trenches and put several PVC pipes in, to be able to provide the amount of airflow necessary for cooling a whole house.)
The entrance of that/those pipe(s) is/are connected (underground) to the house/refrigerator air. So step one is to COOL the (house) air (or NOT HEAT the refrigerator air!) in the (first) underground tube(s) down to near the deep soil temperature
The exit of that/those PVC pipe(s) is/are connected to send the air past the INTAKE flapper valve inside the drum-cylinder. As the piston recedes inside the cylinder, it causes a suction effect which causes the flapper valve to be pulled open, allowing the incoming air to enter. The Flapper Valve can be as simple as an eight-inch square piece of thin rubber such as from an automobile inner tube, with two pieces of thin aluminum metal attached to it. A STRIP of aluminum is BOLTED to the drum end, ABOVE the pipe entrance, squeezing the flexible rubber between. This allows the rubber piece to HANG FREE and block off the opening due to gravity. The other piece of aluminum is mounted to the BACK of the hanging area, possibly with strong adhesive, and being a CIRCLE of maybe 6" diameter. The purpose of this piece is to keep the rubber FLAT, so it would not get blown open by air pressure! An additional RING of rubber might be attached (by adhesives) AROUND THE OPENING in the drum end, to even better ensure air-tightness of the flapper valve when it is closed.
The Savonius windmill, spinning up above at around one time per second, turns the simple crankshaft lever. The two Flapper Valves then automatically open and close as necessary. The piston never moves at even walking speed, so friction and wear and tear against the drum walls is minimal.
This then creates slightly compressed air, which gets sent into the second pipe. The pressure begins very low, but as long as there is wind to blow, pressure would keep being added into the OUTLET pipe (and buried storage tank), as long as air was being provided at least as fast as it was being removed for usage. Here is the first really important part here. In the process of compressing air, it heats up! This is a natural situation which always occurs. So Step two is in compressing the air in the drum/compressor, to CAUSE it to heat up like that! Air is pretty close to what is called an Ideal Gas regarding such things. This is technically called an isentropic compression, because it does not change the Entropy of the air in the process of the compression. There are simple and standard equations (provided below) that can calculate the temperature the (compressed) air gets up to, due to this effect of the compression.
Step Three is in sending that self-warmed air through a second underground tube, to again let it cool down to the deep soil temperature.
When you RELEASE that pressure, the same formulas apply again! But this time, since we are releasing the pressure, the air COOLS DOWN. This is the fourth and final step in the process, where cool or cold air is produced!
FYI, the science of the description above is nearly EXACTLY what happens in your home A/C system and your own refrigerator and freezer! We are just describing very low-tech ways of accomplishing each of those steps, without having to use Freon or Ammonia or other refrigerants. In case you are curious, before Freon was discovered, all refrigeration and freezing equipment used either ammonia (which is a very dangerous material and not like the very diluted stuff you use at home) or compressed-air refrigeration. So this is not as though we are recommending some bizarre concept! It is actually generally considered an OBSOLETE concept, as THIS concept of refrigeration was actually invented in 1844 by a guy named John Gorrie! Compressed-air refrigeration was used fairly broadly for the rest of the 1800s and into the 1900s, but when Ammonia refrigeration was developed, it rapidly took over the bulk of the refrigeration market. Unfortunately, when such Ammonia equipment would fail and release concentrated Ammonia gas, people tended to die! So safer substitutes, generally the family of Freon refrigerants, were invented! (Freon or ammonia or any other refrigerant has one advantage over our type of air-based refrigeration. During the phase just after the compression, the refrigerant CHANGES STATE from being a compressed gas to becoming a liquid. The heat exchanger which does this is therefore called the Condenser! That change-of-state involves a great deal of energy being removed from the refrigerant, far more than just cooling a gas or liquid can give up. This then allows GREATER refrigeration effect when that compressed [and cooled] liquid refrigerant later has its pressure released.) Our theme here is that YOU can accomplish the SAME refrigeration or freezing processes with a low-tech crude cylinder air-pump that you can make. Yes, you will be using Gorrie's technology of 160 years ago, but it is certainly WELL proven! And it works excellently! You are free to spend $700 on a conventional refrigerator that forever uses a lot of electricity! Gorrie's and our approach is DIRT cheap (pun intended!) and it uses very little external power, which a crude Savonius rotor windmill can provide. Ditto for Third World people who have no available electricity and do not have $700 to buy a new refrigerator anyway! Finally, you may have thought ahead and considered using a furnace BLOWER or a FAN to do the compression. Won't work! Blowers and fans are great at MOVING air, but they are lousy at COMPRESSING it. Some (expensive) Industrial blowers can develop 1 PSI or 2 PSI pressure, but we will see below that that is not enough for our needs.
If you have ever used a carbon dioxide fire extinguisher, you know that frost forms around the outlet, and the valve can even freeze up and clog! It is NOT because carbon dioxide is naturally cold or anything! But it was COMPRESSED when it was put into that fire extinguisher. When that pressure is released during use, the rapidly expanding carbon dioxide that comes out can become extremely cold, due to this exact same Ideal Gas effect we are discussing here (in our final phase of the releasing of the pressure).
(For now, we are still discussing here a moderate climate where the deep soil is around 65ºF [like maybe Alabama]). Say that we only compress the air to just around 8 PSIG. This is REALLY easy to do! (With just your mouth, you can provide around 2 PSIG pressure to blow up balloons, etc, so 8 PSIG is a very minimal pressure to be producing with the drum-compressor.). After this minimal compression, the air only rises to around 599ºR or 140ºF. This rather warm air goes through the second underground tube system and is cooled back down to near the 65ºF of the deep soil. Remember that our air cannot CONDENSE, but it accomplishes the same effect in that second underground tube as a Condenser does with a refrigerant. When we later release that pressure, we find that the air gets cooled by around 65ºF. For this climate being discussed, this would result in air at 0ºF, which would be excellent for sending into a food freezer.
But in a hotter climate, as in an African jungle where the ground temperature is near 100ºF, this would result in air at around 35ºF, suitable for sending into a refrigeration box, not cold enough to create ice, but still plenty cold enough to preserve food. For that extremely hot African climate, a slightly higher compression would be necessary to provide freezing of food. We will consider a variety of other climates and applications below.
You might see from this example that you may want to select a specific pressure for the system depending on the climate that is present and the application you intend to accomplish. That pressure can be established by choosing how much air you will run through this system to compress, AND by how fast you will be releasing that compressed air at the other end to produce the desired cooling effect. It NEVER hurts to over-design a system, where it either does or can provide more compressed air at higher pressure than you actually need, because you can always control the actual cooling effect by adjusting the rate that air is released in the refrigerated chamber. Below are the formulas and a bunch of examples to guide you regarding this stuff.
You could even provide less air conditioning! You might choose 2 PSIG pressure. The compressed 85ºF air from the house warms by about 17ºF to around 102ºF due to being compressed in the drum-cylinder, and then drops back down to the 65ºF deep soil temperature in the outlet tube, and then drops down an additional around 18ºF when the pressure is released, down to around 47ºF. That is low enough (below 60ºF) to cause nearly all the water vapor in that air to condense, which dehumidifies the air to the desired level. That air would then be sent directly back into the house (where it had initially come from!) as cooled and dehumidified air!
All three of these functions will work fine no matter how hot the climate is! So any house or building anywhere in the world can have refrigeration, a food freezer, and air conditioning, without using any electric power at all! Even a remote hut in a jungle near the Equator can therefore have air conditioning! And more importantly, safe food preservation! The only difference, as we will soon see is regarding the pressure we need to compress the air to!
We are needing a VERY MINIMAL compressing of air (and nothing else), and so there are many alternate ways of doing this moderate air compression. You could find a piece of large diameter metal pipe or sturdy tubing, and make the cylinder-pump out of that instead of using a drum
You might be surprised to learn that MANY commercial air compressors use such flapper valves to allow air into and out of the compressor cylinder, and they can generally produce more than 100 PSI of pressure! Your homemade flapper valves may not be that excellent, but they do not need to be, because the pressure you will need are far lower.
These devices are simple enough and they are made of items that may be available even in Third World locations.
T2/T1 = (P2/P1)(n-1)/n
n is a number that is specific to a type of gas and the process occurring. For air in isentropic expansion or compression, n is very close to 1.4. This results in that exponent being around 0.287.
T2/T1 = (P2/P1)0.287
All you need to remember is that these are ABSOLUTE pressures and temperatures, meaning that a normal day might start out with 15 PSI air (atmospheric pressure) (called 15 PSIA, which is also 0 PSIG, or gauge pressure) and 527ºR temperature (the absolute temperature that is the same as 68ºF.)
579ºR/459ºR
so the fraction is
1.2614
Because of the exponent, the ratio of the pressures is therefore
2.245
Since the ambient air pressure is 15 PSIA, this means that the bellows or cylinder would need to produce around 15 * 2.245 or 34 PSIA which is also 19 PSIG. This can be hard to achieve, especially with bellows. So for full food freezing when the air temperature is 120ºF, the underground intake tunnel may be necessary. In that case if the 120ºF air is cooled to the 80ºF deep soil temperature before it gets compressed, and we would have a different calculation, where the fraction would be:
539ºR/459ºR
so the fraction is
1.1743
Because of the exponent, the ratio of the pressures is therefore
1.75
This results in needing only 15 * 1.75 or 26 PSIA or 11 PSIG rather than 19 PSIG to get the needed freezing. This is a significant improvement, and it is ENTIRELY due to the effect of the INTAKE DUCT cooling the air BEFORE it is compressed! It still would be solid freezing food at 0ºF on a day when the air temp is 120ºF, an impressive accomplishment!
559ºR/489ºR
so the fraction is
1.1431
Because of the exponent, the ratio of the pressures is therefore
1.59
This results in only needing 15 * 1.59 or 24 PSIA which is 9 PSIG to be provided by the bellows or cylinder to provide the needed refrigeration.
And finally, we can consider using the underground intake tunnel for this refrigeration. In that case if the 100ºF air is cooled to 70ºF before it gets compressed, we would have a different calculation, where the fraction would be
529ºR/489ºR
so the left fraction is
1.0818
Because of the exponent, the ratio of the pressures is therefore
1.31
This results in needing only 15 * 1.31 or 19.5 PSIA which is 4.5 PSIG where a bellows or a simple cylinder pump can easily provide that for the desired refrigeration.
We have not really discussed here the AMOUNT OF ENERGY involved. THAT is the analysis which can determine just how large and powerful the air pump must be. For food preservation by refrigeration or freezing, we feel those calculations should be unnecessary here, as the dimensions and figures described above should all be fine for any climate (for one family). But even if it should turn out that not quite enough refrigeration is obtained for an application in Indonesia, we would then simply recommend making a duplicate second system to provide the additional refrigeration needed. (The calculations can be fairly involved.) For full air-conditioning applications, those calculations are likely necessary to do, and a local Engineer should be found to do them for you. They involve first determining the total amount of energy (actually power) that would be required for the cooling effect desired. Then a multiplier is used to account for the fact that the different processes here are not perfectly efficient. This then gives the amount of power that would be needed to be removed in the phase where heat is lost from the compressed, heated air in the (second) underground tube, and you can then work backwards to calculate the amount of power required in compressing the air in the first place.)
However, the food cooks rather slowly, much like a Slow-Cooker or a Crock-Pot.
So, as either a side-benefit of the HG 3a heating the home, or as an independent system exclusively to service the greenhouse, the HG 3a unit can enable a small greenhouse to produce five times the fruits and vegetables during a normal growing season, in addition to the possibility of heating the greenhouse all year and thereby producing far more crops yet. Generally, really small greenhouses are hardly worth the effort as they produce so little, but if that same small greenhouse can produce five times as much, or possibly ten times as much food as normally, the whole concept of self-sufficiency regarding food becomes far more realistic.
These first several are simply a pattern of buried PVC or field tile tubes, buried at TWO different depths! One set of the tubes would be at a depth of at least three feet, so the surrounding temperature of the deep soil would be around 52ºF or so. The other set of tubes would be just a few inches below a specific surface area. IN WINTER, the 52ºF air going through those tubes (pushed by a blower of some sort) would WARM up the surface immediately above it.
See the general theme here? With some creative thought, there are an immense number of uses for nearly unlimited amounts of 52ºF air. It is certainly excellent for air conditioning in the summer, but these examples show ways it can also be very useful in winter, even though it is at such a low temperature (52ºF) that it might initially not seem useful at all!
Similarly, there are a lot of possible uses of the 150ºF humid air that the HG 3a unit can provide. Etc.
There are also SUMMER applications for the two-sets-of-tubes concept. Here is a rather silly application, which will never be installed! I spent much of my adult life playing semi-pro volleyball, and a lot of that was in extremely hot beach sand! Most players wear little stockings to keep from burning their feet during long tournaments! Obviously, I realized that if this arrangement of two sets of underground tubes was installed, with one set four feet deept to capture the coolness of 52ºF deep soil (or sand) and the other set just six inches deep, to run that cool air through the extremely hot (120ºF) sand, we could have enjoyed far more pleasant tournaments! The expense of doing that is far too great for just the benefit of some sissy volleyball players not having to wear socks!
Imagine buying around 30 lengths (ten feet each) of 4" diameter PVC (thickwall) pipe, along with the couplings and solvent cement for it. They will be erected in a vertical tower, with guy wires for stability, or inside a drilled well or in a cave. At the very top of the PVC pipe would be a funnel that could collect rain from an area that might be 6 feet square. The bottom of the whole thing would be blocked off with an end cap, but first there would be a Tee and reducers to provide a small (1/2") connection to standard piping.
When this was first installed, it would be empty of water, right? But a first rain, of maybe 1/2" total rainfall, would funnel around 1.5 cubic feet of water (ten gallons) into the tube. That would fill around 18 feet of water into the tube. Very little water would ever evaporate from inside it, so after about 15 more rains, the entire 300 feet of the tube would be filled with water.
Why is this of any use?
Well, the PRESSURE in the water increases by about 15 PSI for each 32 feet of vertical water stacked up. So we have provided around 150 PSI of water pressure to the standard piping we attached at the bottom. This pressure could be brought to a nearby air tank arrangement, where a tank of compressed air at 150 PSI would then be available. This could power things like paint sprayers or automotive pneumatic tools or assorted other equipment.
The pressure of the water itself could be used for hydraulic equipment. It may be best to use the pressurized water to transfer pressure to hydraulic fluid (to avoid corrosion issues) but then some hydraulic equipment could be driven by this energy source!
As always, note that this is absolutely GREEN, and where the results are comparable to conventional air compressors or hydraulic pumps, but without needing any electricity to run any motors or any other fossil fuels to drive any other power supplies.
This is another concept which may not be of any great value. It's inclusion here is again mostly to show you that some creative thought can find wonderful new solutions to many problems of modern life!
So, try to avoid those few web-pages of mine, as I guess I was not as nice and friendly as I try to usually be!
One of the central aspects of attempting to be Independent is that you would not need a steady stream of repair people coming to fix things that had gone wrong! Another is that the ONLY sources of energy required for these things are absolutely GREEN! The HG 3a unit operates entirely on leaves and grasses that you can certainly find locally. The refrigeration and freezer and electricity recharging MIGHT require some wind power from some very simple and crude Savonius rotors (unless you have a waterfall nearby or other obvious source for mechanical power). The devices to provide safe drinking water are equally independent of any power-grid or LP gas delivery truck or any gasoline tank!
By the way, the HG 3a presentation mentions a FUTURE capability that I believe that system will be capable of, that of creating a substantial amount of electricity, possibly based on the Seebeck Effect of thermoelectric generation, but somewhat modified. If someone every finds a way to use an HG 3a for such a function, it might provide a whole new way of supplying us all with electricity, even maybe for future electric/battery-powered vehicles! But that is liable to be some years off! (I expect to add a variant HG 4a device sometime soon!)
A Campus where Builders could learn to Build 14 different Houses using these methods.
C Johnson, Physicist, Physics Degree from Univ of Chicago