Appropriate Technology

Sustainable Civilization: From the Grass Roots Up

Appropriate Technology Appendix

Technology is the total collection of tools and knowledge used by a population to alter aspects of the environment to meet human desires. Technology must be appropriate for the location, the capabilities of the population, and the available resources. Building a waterwheel in the sands of a desert would be useless, as would handing control of a nuclear reaction to some remote un-educated tribe, or giving the tribe gasoline fueled pumps.

The U.S. patent office estimates 1 patentable invention per year, per every 1,000 people in the population. But don't let statistics mislead you into believing that mere number of people will mean progress. Knowledge and technology tend to feed back into each other toward more complex systems.

It takes creative people, educated and with extra time and resources for significant advances. It takes easy access to previous knowledge, tools, expert assistance, etc. An information and goods exchange among a network of communities should be expected to yield far more new inventions each year than the same communities in isolation. Communication and trade must be maintained, which in a low energy environment probably means being physically nearby.

Not every invention is in the best interest of civilization (think of a device that could destroy every living thing, so simple to make any kid could do it...) Even without posing a physical threat, inventions are not necessarily welcomed with open arms. There are always those who oppose anything new. With innovation the demand for a product or service may wane (buggies and horsewhips after the auto).

Not every site has the same resources. Not every group of people has the same capabilities or interests. Specialization nurtures expertise. Trade nurtures specialization. But it also nurtures the "theft" of inventions, reducing the reward for the inventor’s efforts, and encouraging the natural protection of an invention, secrecy. We need an environment that nurtures positive creativity, avoiding careless waste of resources, contamination of the environment, and unacceptable risks. Thoughts?

INTRODUCTION

Can you obtain and manage sufficient water to not only sustain your present direct use, but also provide for a subsistence garden, or more? What else would make your life "better"? This appendix presents simple concepts useful to sustain a higher standard of living in the absence of our present high energy globally connected infrastructure.

The definition of appropriate technology readily changes with your local situation. P/V modules are great for the desert, but of questionable vale in an area of constant overcast or precipitation. What it is NOT is designed in weaknesses such as easy to wear out parts or construction of poor quality materials.

It must be something that can be understood, maintained, repaired or replaced locally, or something where such can be obtained from elsewhere by assured sustainable trade.

It is that which is available, affordable, and sustainable in the most likely situations.

It needs to be designed with recycling in mind. This consideration is something that has been essentially ignored in our century+ long oil party.

Individual invention needs to be integrated into a larger view throughout the relevant organizations with readily available communication, to avoid the situation where numbers of people are over and over "reinventing the wheel".

In smaller communities technology might degrade to the extent that it is mere handicraft of some naturally grown object.

SUGGESTED SOURCES

Numerous articles on creating your own "home grown" technology are available online at http://www.vita.org and at http://www.itdg.org. When the functional lifespan of your purchases ends, will you still have a need for the product or service? If so, can you repair or replace it with what you have remaining? The greatest source of energy on Earth, is the sun. It evaporates water for rain, powers worldwide thermal currents in the air and water, and thru photosynthesis provides all of the food consumed.

TECHNOLOGY PLANNING

If solar panels have a useful life of 20 to 30 years, and I anticipate a continuing need for electrical power, I have that long to find an alternative. Silicon cells are a high tech process. Low tech p/v cells can however be made from blackened copper, and thermocouples also offer direct sunlight (heat) to electrical power conversion.

The turn of the millennium technology and infrastructure is dependent on fossil fuels for power and feedstock. Potentially during the lifespan of the young of today, any significant use of fossil fuels will end.

TOOLS

With a modest collection of quality hand tools, even a neophyte can make modest repairs, disassemble obsolete equipment, or fashion vital devices. Imagine trying to "double dig" your garden without a shovel, or loosen a bolt without a wrench. Obsolete devices are a potential "goldmine" of parts and raw materials.

AIR TECHNOLOGY

Choking smoke or dust, too much CO2, too little O2, biological threats, poisonous gas, or other toxic or dangerous substances. You could easily find you need to at least temporarily seal yourself inside a bubble of clean air.

CO2 filtration: Appropriate technology engineering example of a homemade re-breathing device. Two liter soda bottle of water, which should absorb 2.1 qt of CO2. This is roughly 10% of what a person exhales in an hour, or 6 minutes. To avoid going below 15% O2, this unit needs to start with about 1.2 cubic ft. (8.98 gallon) of air. I could easily envision a backpack with two 2 liter bottles of water, and a plastic bag of 2.4 cubic feet (around 18" wide, 24" high, and 10" thick), to provide an expedient 12 minute supply of self-contained air.

On a larger scale if you wanted to absorb the CO2 for a person for the entire day it would take around 480 liter (about 127 gallon). Circulate this water in a "waterfall" such that a full day of in home circulation is run the next day in the greenhouse area.

CO2 biological exchange. Studies have shown that essentially equal photosynthesis takes place in 5 grams of plant mass distributed in a square meter of open water, and in 10 kilograms of plant mass in a square meter of forest e3nvironment. A clear implication is that while plants growing in "air" provide a larger standing mass, aquatic plants are a greater source of oxygen regeneration. (Draw your own conclusions about damage we're causing to the ocean's ecosystem.)

NASA studies indicate that one cubic meter of actively growing wheat, grown hydroponically under 24hr/day light, can meet the oxygen needs for one person, while producing the food value of about 1/3 of a bowl of cereal per day. The NASA research conflicts though with the lower technology 2 year experience at "Biosphere II", where 3+ acres was not sufficient, when a relatively extensive soil biosystem was included in the container. (Microorganisms in the soil, and the concrete structure were found to be absorbing oxygen.)

Other experiments show that approximately 8 gallons of well aerated algae in sunlight balances the breathing of a typical human. (Remember, you need enough "extra" air volume to carry you past periods of dark/dim light.) If you're not bubbling the air thru the algae, set up a "surface area" of water for the 8 gallons at about 8 meters square. (A square about 9 feet on a side) Since the water alone weighs 64 lbs., if this is to be a portable unit, you'll want some type of cart.

Some plants such as cacti, aloe vera, etc. produce oxygen in the dark, vs the light.

COMPENSATING FOR ATMOSPHERIC PRESSURE VARIATION

An airtight home must have a flexible lung (see Biosphere II) to allow  internal/external air  pressure to remain equal, without actual exchange of air. It can be as simple as a large trash bag on one end of a pipe that penetrates a wall. Typical atmospheric pressure changes do to weather may amount to 2% to 5% of the volume of the sealed container. If you have a 1200 ft. sq. home (above), the "lung" should be between 168 and 420 cubic feet. (Don't panic, that's only a box 8 foot on each side max) The device must account not only for the pressure changes due to weather, but from heating and cooling of the air inside the sealed area.

ELIMINATING TOXIC GASES

Filtering thru biologically active soil removes significant contamination. Further processing thru sealed areas of selected plants, and activated charcoal.

KILLING GERMS

Envision a device where all of the air being taken in must pass thru a relatively small opening. The device has a lens or mirror that will concentrate intense sunlight into the hole when the device is positioned aimed at the sun. This should cause a small very high temperature zone where the air must pass thru, killing germs. In that ultraviolet kills more readily, are there lenses that concentrate U/V?

KNOWLEDGE

Web and computer files are the fastest means of finding and gathering information, but rely on continued computer technology. Unfortunately for surviving humanity, the web may be an early victim of the collapse. Download to local storage any file you file valuable, and print all of those you find essential. Microfiche is a means of storing a great deal of information in a small package, that can be read with a child's toy microscope

Books probably remain the most practical means of gathering, storing, and passing on knowledge. Your local library should be able to order for you on "interlibrary loan" virtually any book. Read, please! A potential sustainability library (with a lean toward a desert environment) is in the Bibliography Appendix. Used bookstores, several of which have online search functions, can yield may priceless "gems".

COOKING

Every day, the sun provides to virtually every square yard on earth more energy that a person needs to cook a meal, or heat water for pasteurization. There are many approaches to concentrating and using this energy. A relatively portable yet easy to construct is to form a reflector like a giant funnel, with a black cooking vessel at the bottom of the funnel. To build up the heat without letting the air cool it, contain the vessel in clear plastic or glass.

A piece of flat cardboard (if you are going to glue shiny stuff onto it) or reflective substance about 2 feet wide by 4 feet long. (The length should be just twice the width. The bigger, the better.)

At the middle of either long edge, cut a half circle out of the cardboard, along the bottom.

When the funnel is formed, this becomes a full-circle and should be wide enough to go around your cooking pot.

For a cooking vessel, consider a canning jar.

The cooking container should be black on the outside. Scrape off a vertical stripe so that you have a clear glass "window" to look into the vessel, to check the food or water for boiling.

Set the cooking container on an insulator. Put a plastic bag around the cooking-jar and insulator to provide a green-house.

HEATING Think Outside the Box - Strange Thought on Heating… An experiment I never got around to trying… use of a small propane powered fridge as a heater… A gas powered fridge is a heat pump. Say the fridge is framed into a south facing wall, and instead of the solid door it has glass. Inside the fridge are containers of water. The flame, while vented, is inside the home envelope, as is the coil that radiates heat. The cooling system trys to take heat out of the fridge, which ends up inside the house. Whatever the COE, it SEEMS logical that it is going to provide more heat than the flame alone could. In a more normal use, the fridge can be driven by any concentrated heat source, even focused sunlight. THERMAL STORAGE

Heat energy moves by conduction (hot objects touching each other), convection (physically moving flows of heated mass, water, air, etc.), or radiation (infrared light). Water stores, conducts, and convects heat well. An advantage of water for moving heat is that although it does convect, the density difference is not so great that a low power pump cannot move "hot" water to a physically lower position.

Earth tubes are an approach combining conduction and potentially convection to provide not only ventilation for a structure, but storage / moderation of heat. The "traditional" approach is a grid of buried tubes, about 4' apart. Using air as the exchange medium, the tubes need to be at least 4" in diameter, and 60 feet long. Multiple tubes provide "extra" surface area to contact the earth, and exchange thermal energy.  The volume of soil available for thermal storage is essentially limited by how deep you are willing to dig you trenches.  (With lots of backfill of course.)

Heat energy moves by conduction (hot objects touching each other), convection (physically moving flows of heated mass, water, air, etc.), or radiation (infrared light). Water stores, conducts, and convects heat well. An advantage of water for moving heat is that although it does convect, the density difference is not so great that a low power pump cannot move "hot" water to a physically lower position.

We've only done this with a model solar home. In the model, the pump was powered by the amount of solar panels that would fit on a 3x5 index card. That water flow should be sufficient though for one actual heat exchanger tube.

On a real-life scale, say:

4" diameter outer tubes, open at the top, sealed at the bottom. 1" diameter inner tube, open at the top and bottom

Filled with water to the top.

Pump "X" only needs to move a trickle of water from top surface of outer to inner pipe. Due to volume difference, warm water moves down center pipe much faster than it returns up larger outer volume, warming the soil as would any other earth tube.

With a modest well-drill, suitable for a shallow hand-pump well, drill multiple holes say 20 to 30 feet deep, on a grid of about 4'. Put one of these water filled heat exchangers in each hole.

^X> [[~] ] Exposed tubes black  [[~] ] -or any other method [[~] ] to heat the water [[~] ]_________ Ground Level [[~] ] [[~] ] [[~] ] [[~] ] [[~] ] [[~] ] [[~] ] [[~] ] [[~] ] [[~] ] [[~] ] [[~] ] [[~] ] [[~] ] [_______]

WATER TECHNOLOGY

Water Collection from "Dry" Air. Before modern dehumidifiers, there were methods shown usefull in precipitating water from the air.

Dew ponds appear to predate history. They are large but shallow artificial pools, smooth rock to protect the water tight layer, with the entire pond insulated from the ground below and around.

A pond described in Popular Science (September 1922 is a concrete cistern about 5 feet deep, with sloping concrete roof, above which is a protective fence of corrugated iron said to aid in collecting and condensing vapor on the roof and prevent evaporation by the wind. The floor of the cistern is flush with the ground, while sloping banks of earth around the sides lead up to the roof. Moisture draining into the reservoir from the low side of the roof maintains the roof at a lower temperature than the atmosphere, thus assuring continuous condensation. At one side of the reservoir is a concrete basin set in the ground. By means of a ball valve, this basin is automatically kept full of water drawn from the reservoir.

In 1932, Achille Knapen built an "air well" in France. The structure was described in Popular Mechanics Magazine to be about 45 feet tall with walls 8 to 10 feet thick. The claim is the aerial well will yield 7,500 gallons of water per 900 square feet of condensation surface. At night, cold air pours down the central pipe and circulates through the core... By morning the whole inner mass is so thoroughly chilled that it will maintain its reduced temperature for a good part of the day. The well is now ready to function. Warm, moist outdoor air enters the central chamber, as the daytime temperature rises, through the upper ducts in the outer wall. It immediately strikes the chilled core, which is studded with rows of slates to increase the cooling surface. The air, chilled by the contact, gives up its moisture upon the slates. As it cools, it gets heavier and descends, finally leaving the chamber by way of the lower ducts. Meanwhile the moisture trickles from the slates and falls into a collecting basin at the bottom of the well.

The French inventor L. Chaptal built a small air well near Montpellier in 1929. The pyramidal concrete structure was 3 meters square and 2.5 meter in height (10 x 10 x 8 ft), with rings of small vent holes at the top and bottom. Its 8 cubic meters of volume was filled with pieces of limestone (5-10 cm) that condensed the atmospheric vapor and collected it in a reservoir. The yield ranged from 1-2.5 liters/day from March to September. The total weight of water was 190 lb; the maximum yield was 5.5 lb/day. Chaptal found that the condensing surface must be rough, and the surface tension sufficiently low that the condensed water can drip. The incoming air must be moist and damp. The low interior temperature is established by reradiation at night and by the lower temperature of the soil. Air flow was controlled by plugging or opening the vent holes as necessary.

Calice Courneya patented an air well in 1982 (USP #4,351,651): A heat exchanger at or near subsurface temperature... is in air communication with the atmosphere for allowing atmospheric moisture-laden air to enter, pass through, cool, arrive at its dew point, allow the moisture to precipitate out, and allow the air to pass outward to the atmosphere again. Suitable apparatus may be provided to restrict air flow and allow sufficient residence time of the air in the heat exchanger to allow sufficient precipitation. Furthermore, filtration may be provided on the air input, and a means for creating a [negative] movement pressure, in the preferred form of a turbine, may be provided on the output... The air well is buried about 9 feet deep. The entrance pipe is 3-inch diameter PVC pipe (10 ft long), terminating just near the ground... This is an advantage because the greatest humidity in the atmosphere is near the surface." (7, 8) (Figure 4)

Air flows through the pipes at 2,000 cubic feet per hour at 45oF with a 5 mph wind. This translates to about 48,000 ft3/day (over 3,000 lb of air daily). Courneya’s first air well used a turbine fan to pull air through the pipes. Later designs employed an electric fan for greater airflow. At 90oF and 80% Relative Humidity (RH), the air well yields about 60 lb water daily. At 20% RH, the yield is only about 3 lb/day. The yield is even lower at lower temperatures. The yield depends on the amount of air and its relative and specific humidity, and the soil temperature, thermal conductivity, and moisture.

Acoustic resonance within the pipes might enhance condensation. The more recent invention of acoustic refrigeration could be used to advantage, as well as the Hilsch-Ranque vortex tube.

It is necessary to cool the air to the "Dewpoint". All of the preceding devices appear to rely on night cooled mass to provide the needed temperature difference, yet leave the device open to daytime heating by the sun. I find indications that even in the daytime in certain conditions it might be possible to radiate to the sky 100 to 200 BTU per hour, which strictly in math could represent 1 pint or so of operation for every 10 square foot or radiation area.

Once the water has condensed the "dry" air, now cool, needs to be exhausted. This points out the flaw in all of the above. None of the above low-tech devices provide for heat exchange directly between the incoming and outgoing air, therefore the "coolness", essential to precipitation, imparted to the incoming air is directly exhausted, and rapidly eroded.

Ideally, there should be sufficient heat exchange between intake and exhaust air that at the pipe open ends, they are virtually at the same temperature, despite being cycled thru a chilled spot. The transition between liquid and vapor water is, absent unknown science or magic, a matter of the transfer of 970 BTU per each pint condensed. (7760 BTU per gallon)

Using a sky radiation approach to cooling your condenser core, if the latent heat of vaporization of water is 2.26 × 106 J/kg a 1 m2 radiator can provide 50 W/m2 of cooling, enough to condense 1 g of water in 45 s; 1 kg in 12.6 hr; or 1.9 kg per day. Reportedly production rates in the Southwest U.S. can average about 2 liters per day in the winter to over 6 liters per day during the summer, per square meter.” At the low end 10 m2 (1/4 acre) of radiators cooling humid air could produce 19 L of water per day. The humid air must of course be moved thru the cooling unit, and the “coolness” used to change air temperature recovered during expulsion of the “dried” air.

A commercial, powered water condenser is sold under the name Aqua-Cycle, invented by William Madison, introduced in 1992. It resembles a drinking fountain and functions as such, but it is not connected to any plumbing. It contains a refridgerated dehumidifier and a triple-purification system (carbon, deionization, and UV light) that produces water as pure as triple-distilled. Under optimal operating conditions (80o/60% humidity) the unit claims to produce up to 5 gallons daily.

ATMOSPHERIC CONDENSER DISCUSSION

At any given pressure and temperature, in a fixed volume only a limited amount of water will evaporate into vapor, the limit is referred to as the dew/saturation point. A cubic meter of normal sea level air has a mass of 1.292 kilo. A cubic meter of water vapor at sea level pressure has a mass of .804 kilo, this would occur at a temperature of 100C (212F).

At 0 C (32 F), saturation point is about 1.1 gm of water per cubic meter. A rule of thumb is that raising the air temperature 18°F (10°C) doubles its moisture capacity. This means that air at 86°F (30°C) can hold eight times as much water as air at 32°F.

Degrees C	Degrees F	Gram H2O 0	32	1.1 10	50	2.2 20	68	4.4 30	86	8.8 40	104	17.6 50	122	35.2 60	140	70.4 70	158	140.8 80	176	281.6 90	194	563.2 100	212	1126.4

Relative humidity is the percentage of water vapor present as compared to how much there could be at the present temperature.

Take a typical Tucson fall day of 84 F and relative humidity of 7%. There is roughly 7% of 8.8 grams of water in each cubic meter of air (.616 gram). Lower the temperature to 66 F, and relative humidity doubles to 14%. Lower the temperature to 48 F, and relative humidity again doubles, now to 28%. If we cool air without changing its moisture content, eventually we'll reach a temperature at which the air can no longer hold the moisture it contains. Then water will have to condense out of the air, forming dew or fog. The dewpoint is this critical temperature at which condensation occurs. But, water does not immediately change state as the temperature reaches the "right" point. The "Latent heat of condensation" (Lc) refers to the heat that must be removed from water vapor for it to change into a liquid. Lc=2500 Joules per gram (J/g) of water or about 600 calories per gram (cal/g) of water. Specific heat is defined as the amount of heat energy required to raise 1 g of a substance by 1° Celsius. If the specific heat of air is .25 calories per gram of air per degree C change, then each degree C change in a cubic meter represents 323 calories. The specific heat of water is 1 calorie per gram per degree C. In our Tucson fall day above there was .616 grams of water in a cubic meter of air. Air and water vapor together take a change of about 324 calories per degree C. We need to lower the temperature by around 40 C, or get rid of 12,960 calories of heat to reach the dew point. An additional 379 calories of heat needs to be removed to compensate for the latent heat of condensation, for a total of 13,339 calories. Assume a daily water need of 174 gallons (658.6 liters) - 658,660 grams of water. In a Tucson fall day, each of us would need to "wring" all of the water out of more than a million cubic meters of air (1,069,252) - a cube 100 meters on a side. The heat to be moved is about 14 billion calories. The water portion of this number is about 450 million calories. Depending on device efficiency, SOME part of the other 1 billion calories should be able to be conserved in a heat exchanger. Increasing the pressure also changes the dew point. Double the pressure and relative humidity doubles. Assume normal atmospheric pressure of 14 PSI. Pump the fall Tucson air into a tank at 28 PSI and the relative humidity inside is now 14%. Make it 56 PSI - 28%. 102 PSI - 56%. 204 PSI - 102%, and you've got water accumulating in the bottom of the tank. A SHOCKING APPROACH If you have electricity in abundance, in 1945, South Africa's chief meteorologist, Theodore Schumann, proposed the construction of a unique cloud-condenser on top of 3,000 ft. Table Mountain on the south side of Capetown. Schumann's design comprised two large parallel fences of wire netting, one insulated and one grounded, which would be charged with a potential difference of 50-100 KV. The wire screens were to be about 150-ft. high, 9,000 ft. long, and 1 foot apart. He estimated that the electrified fence would condense as much as 30,000,000 gallons daily from "The Cloth", a perpetual cloud that crowns the peak. The fence was never built.

I am unclear about the COE of water per watt consumed.

NASA has proposed replenishing water during a mission on Mars by using a device whith extracts water vapor from the Martian atmosphere by adsorption in a bed of type 3A zeolite molecular sieve. Using ambient winds and fan power to move atmosphere, the WAVAR adsorbs the water vapor until the zeolite 3A bed is nearly saturated and then heats the bed within a sealed chamber by microwave radiation to drive off water for collection. The water vapor flows to a condenser where it freezes and is later liquefied for use in the life support system. THERMAL STORAGE

Heat energy moves by conduction (hot objects touching each other), convection (physically moving flows of heated mass, water, air, etc.), or radiation (infrared light). Water stores, conducts, and convects heat well. An advantage of water for moving heat is that although it does convect, the density difference is not so great that a low power pump cannot move "hot" water to a physically lower position.

Earth tubes are an approach combining conduction and potentially convection to provide not only ventilation for a structure, but storage / moderation of heat. The "traditional" approach is a single grid of tubes, with direct exhaust from the structure. As John Hait points out in his book Passive Annual Heat Storage, use of two tubes, out the structure top, and one out the bottom, lets the structure breathe, while keeping the loss / gain of temperature due to differences between inside and outside air temperature to a minimum. Using air as the exchange medium, the tubes need to be at least 4" in diameter, and 60 feet long. Multiple tubes provide "extra" surface area to contact the earth, and exchange thermal energy.  The tubes should be around 4' apart.  If you could establish an insulated zone in the pipes that was "extra" cold, that area would dehumidify the air.

Note, radiant heat, whether or not a human can see or sense it, travels in straight lines, and depending on the material interposed, is reflected, refracted, or absorbed. It can, for example, by using an appropriately curved reflector, be concentrated. Envision the two earth tubes passing each other, but with mirrors to concentrate radiant energy from the "hot" tube, possibly on a smaller "cold" tube, or a storage area.

Black coloring "converts" light to heat of a higher temperature that would a white coloring. Nevertheless, if there is no heat exit, even a white collector will gather heat, just bouncing it around as visible light more before the frequency drops to that of heat. Although in nature, the temperature 20 feet in the earth is around the "average" of the exposed surface temperatures, this average can be adjusted. Obviously, it first requires the waterproofing and insulation of Mr. Hait's guide. Then, instead of letting the entire hot/cold timeline thru, limit the flow in your tubes to the hot/cold you want. In my situation in Arizona, I want to store "cold". Even in this climate in the summer, the nights are "cooler" than the days. I need to flow thru my soil at night to the outside, and thru my soil during the day to the home inside. While Mr. Hait and many others concentrate on air tubes, our scale experiments show that where some forced flow of temperate is desired, water filled tubes should work "better" than air filled tubes.

STILLSUIT

Some time ago, when I first read "Dune", I was intrigued with the "stillsuit" concept presented, and that was long before living in the desert. In the cold regions, it is accepted wisdom to dress in layers, and provide some ventilation to release body heat. But in desert climates, the typical "modern" person goes about in short sleeve clothing. Is there a better approach?

The folks who make and market a cold air heat exchange mask, acknowledge they've made warm air tests, and the mask works there also to moderate temperature and humidity. (Look up turbinates and the nose of a camel for the biological inspiration.)

The first daytime goal must be avoiding direct sun, and absorbing the 1 kw per hour per square yard (around 860,000 heat calories, or around 43% of the heat a human generates in an entire day).

Avoiding the heat is not just a matter of avoiding direct sun, but also the heat around you. Heated ground and other objects re-radiate, and heat the ambient air. You need radiant shielding from virtually every physical object that could "illuminate" your body, and conductive / convective shielding from the heat of the air. In theory, if you avoid these radiant inputs, appropriate radiator panels could radiate heat "down" to 20 degrees below ambient temperature.

Yet within your personal microenvironment, you need an air flow so that your sweat can cool your body. In theory the daily heat of a person could melt around 56 pounds of ice (7 frozen gallons - 25 liters) or cause the evaporation of just over a gallon of water (3.7 liters). Therefore if your body was in a microenvironment isolated from thermal energy exchange with the surrounding environment by a perfectly insulating suit, hourly inside your suit your would need to melt ice of just over a pint / just under a liter, or evaporate (and vent) 1/3 of a pint or about 150 ml.

Add a means for one way flow of air, and thermal exchange of incoming/outgoing air, with the potential for some cooling, whether carried "ice", or electromechanical cooling, and you are creating a portable, worn environment.

If you have access to cool evenings, or a home with refrigeration, "phase change" packets that melt at around 60 degrees F, vs 32 degrees for ice, are commercially available. If you need to carry along a cooling system, you probably need availability of a constant 100 watts.

If you are circulating water for internal cooling, bladders at the body "hotspots" provide thermal sinks.

DEFENSE TECHNOLOGY

In history, the English Longbow was about 6 1/2 feet long with a draw of 160 -180 lbs., vs a modern version at 50 - 60 lbs. (My fiberglass bow is 55 lb) The range of the medieval weapon is unknown, with estimates from 180 to 249 yds. Modern versions have a useful range up to 200 yd. A 150 lb. replica longbow was able to shoot a 1.9 oz arrow 360 yd and a 3.3 oz a distance of 272 yd. Modern champion archers maintain that a hit cannot be guaranteed on an individual target at more than 80 yards with any bow. With either or both of enough arrows in the air, and a target enemy close enough together, some hit even at maximum range was almost assured. A military archer during the 14th and 15th Century was expected to shoot at least ten "aimed shots" per minute. An experienced military longbowman was expected to shoot twenty aimed shots per minute. Many war-arrows had heads that were only attached with a small blob of wax, so that if they were to be removed conventionally only the shaft would come out, leaving the head lodged in the victim which would almost certainly cause an infected wound. A weapon to be developed is a crossbow firmly mounted on a multi-axis angle adjustable frame. The bow should in theory maintain the same firing power shot after shot. If the arrows are also close in mass and aerodynamics, after just a few shots and measuring the distance travelled, a spreadsheet should be able to be worked up for any angle/distance desired. Locate side wind resistance charts and integrate and we should have arrow- artillery. The ancients had such devices, for REALLY big arrows. What they did not have was wind charts and computers. For those who fear, or plan on the loss of the knowledge and technology of higher civilization, the atlatls is another "grows on trees" weapon. It upgrades a spear from "hand to hand" status to a significant increase in thrown force and distance. While a beginner will not have much control, the world record for a throw was over 800 feet. The device is a stick about two feet long, with a handgrip at one end and a projection at the back end to fits into a cavity at the back of the spear. The spear is thrown with a sweeping arm and wrist motion. An experienced marksman could probably range out to 150 yards and be accuracte to perhaps 30 yards.

For those interested and in need of a short range but larger weight launching device, there are of course catapults or trebuchet, which put trees and rocks into the arsenal.

WARRANTING FURTHER INVESTIGATION

Bellocq Wave Pump. This device appears to present a "new" mechanical principle, which uses pressure waves from a surface pump, rather than suction, to move water from greater depth that could be pulled by a suction pump.

Reports are that the technology is very efficient in translating energy input into water flow.

The inventor is Toribio Bellocq. Prior to receiving his US Patent #1,730,336 back in 1929, it is reported he had to demonstrate that the device actually worked, without any powered mechanism at the bottom of the pipe. He later improved the pump, as shown in US Patent 1,941,593 issued in 1934. The theory appears to be that the pump imparts harmonic vibrations to the water column that set up standing waves. Other discussions of standing waves include older harmonics experiments by Tesla, and more recent demonstrations of refrigeration with sound waves.

In the pump, a one-way valve at the bottom admits water when the wave relieves pressure there, but prevents water from leaving at the next high pressure impact.

Above sketch from the U.S. Patent Office. For so long as the present web technology remains viable, many patents can be accessed and downloaded for scientific and/or educational review at no cost.

REFRIGERATION TECHNOLOGY

Homemade Icyball. Ammonia evaporation / absorption refrigeration is 18th century technology. WARNING: Ammonia leaks can cause serious injury or death. There are "safer" coolants, this is presented to inspire thought as to what we should be able to do 200 or so years later.

Patents on this type device date though from 1928, patent 1,740,737 and 1931, patent 1,811,523. It is basically two spheres, connected by pipe and valves.

These units use liquid anhydrous ammonia as a refrigerant. The pure anhydrous ammonia is mixed with water. Heat is then applied to the ammonia solution that has been contained in a pressure vessel. The heat drives off the ammonia which then condenses in another pressure vessel.

It needs to be emphasized that ammonia gas is extremely toxic and fammable. One deep breath of pure ammonia gas will KILL a human being. If you are not a mechanically inclined person who pays close attention to details, do not attempt to build one of these units. If built with quality materials and used with the proper precautions this unit can be safely operated since it is designed to contain the gas within the unit.

The system which can be constructed from plans will produce 5 to 7 lb. of ice after being heated for about 90 minutes, any heat source which will result in a final generator temperature of 255 F may be used.

The refrigerant solution is a mixture of distilled water and liquid anhydrous ammonia. Although anhydrous ammonia is not illegal to possess in a closed refrigeration system, it is sometimes difficult to obtain. In some states (especially in the Midwest) laws have recently been passed restricting the transfer of anhydrous ammonia due to its use in the manufacture of crystal meth.

Be sure to check the situation in your state before you attempt to build one of these units!

Don't scrimp on the vessels and the valves. You cannot use the brass valves available in building supply stores. Pressures of up to 250 lb. will be produced within the system. FREON CONTAINERS MUST NOT BE USED UNDER ANY CIRCUMSTANCES.

ROLAMITE

"Frictionless Machines from Rollers & Bands" by Harry Walton. It looks like a simple gadget made with two rollers and a steel band, but it's much more. As basic as the wheel, the lever, or the hinge, it is the only elementary machine discovered this century.

As the rollers are pushed to the right, for example, they turn in opposite directions, but are always in rolling contact with the band. Nothing slides, rubs, or slips; it is always the same points that come into contact between roller and band. And a rolamite unit never needs lubrication. In tests, Rolamite devices display friction of an amazingly low order --- one to ten percent of that in the best ball and roller bearings of similar capacity.

Instead of being uniform, bands can introduce more or less resistance at some point of roller travel. Holes of various shapes can be punched in them to make action easier at a predetermined point and to a precise degree. Bimetallic elements and springs, even cloth, plastic, or rubber bands can be used. Such modification can produce a snap action, sudden braking, latching, and other control functions. A sharply bent band can act as a detent.

Rollers can be fitted with bulges or rubber stops for positive braking. The rollers can be of different sizes. If one is smaller, it turns faster than the other and you have a speed-changing device. Extra rollers may be added, always two at a time.

Perhaps the oddest discovery is that the rollers need not be round. The different shapes of rollers give the Rolamite many additional functions. For instance, a rectangular roller can be designed to lodge against a stop in a braking mechanism.

I just find this thing interesting…

COOLING

A variation of an evaporation / absorption cooling system uses instead of toxic chemicals under pressure, WATER in a vacuum.

An air-tight water canister is placed inside the cooling container. A manually operated vacuum pump pulls a vacuum, which causes the water to boil, with an eventual temperature result of the freezing temperature of water. (In a vacuum, water boils and freezes at the same temperature.)

Outside the insulated container, the system is pipe connected to a canister of the mineral zeolite. The zeolite absorbs the water vapor, up to 25% of its own weight, maintaining the vacuum, and keeping the water "boiling".

Once the zeolite is saturated, the canister is replaced, and sunlight focused on the saturated zeolite can evaporate to the open air the absorbed water, making the canister available for reuse.

In a different venue, a substance such as zeolite is proposed for water collection on Mars. Whether exposed to the wind, or inside a bubble with heated soil, the chemical absorbs the water vapor, which is then boiled off in a sealed container to be re-condensed for human use.

SKY RADIATION COOLING

Referring back to a cone for cooking, consider the same type device as a means of COOLING by radiating heat to the sky while shielding the "hot" object from incoming radiant, conductive, or convective heat around it. Potential cooling is 20 degrees F below ambient air temperature.

Inside your home, near the ceiling, a sealed tank of a liquid to gas phase change material (i.e. water). The boiling temperature of water will lower as the pressure in the system is lowered.

An "air space" at the top of the tank leads to coils / cooling chamber on the roof. (No liquid circulates to the roof from the ceiling tank) Shield the roof unit from direct sun, and from infrared radiation at night from surrounding objects. Water evaporated from the ceiling tank will run back, having cooled. When the roof unit is warmer than the ceiling, water will not condense, and no "reverse" heat exchange should occur. The emitter could also simply be a replacement for a skylight.

Perhaps using some low power means, circulate the liquid in the ceiling tank to an under floor tank for high volume storage.

Depending on local conditions, there may be a 8 μm−13 μm infrared “window” to allow radiation from bodies between 0 C and 37 C. (32-99 F), even if the ambient outside temperature is higher. A horizontal plate sees 180 degrees of sky, which probably includes neighboring trees and buildings, all of which may be radiating more than your emitter. Your emitter needs to be shaded from direct sunlight.

90 % of the sun’s radiance is at wavelengths shorter than 1.7 μm. 99 % of the sun’s radiance is at wavelengths shorter than 4 μm. 99.9 % of the sun’s radiance is at wavelengths shorter than 9 μm. 99.7 % of a 300 K blackbody’s radiance is at wavelengths longer than 4 μm. 99 % of a 300 K blackbody’s radiance is at wavelengths longer than 4.8 μm. 90 % of a 300 K blackbody’s radiance is at wavelengths longer than 7.3 μm.

A cold mirror which reflected waves shorter than 4 μm and transmitted waves longer than 7 μm would allow the radiator to simply face upward through the cold mirror.

The emitter must be covered with an infrared-transparent layer (i.e. polyethylene) to prevent conductive and convective transfer of ambient heat to the emitter.

• The device must reject nearly all direct and indirect solar radiation falling on it. • The device must passively emit the bulk of its thermal energy as infrared radiation. • The cone of infrared emission should be centered near the zenith and not so wide that infrared radiation from hills, buildings, and vegetation is significantly absorbed by the emitter. • Its glazing must be rugged enough to be cleaned of dust, bird droppings, and debris; or the glazing must be inexpensive and replaceable. • Ultraviolet light must be prevented from degrading polyethylene glazing.

A phosphor such as is used to convert blue LED radiance to white light can be used to shift the blue sky to white light. Side walls need to have right angle corner reflectors to retro-reflect exterior heat/light.

Condensation - The latent heat of vaporization of water is 2.26 × 106 J/kg. A 1 m2 radiator providing 50 W/m2 of cooling can condense 1 g of water in 45 s; 1 kg in 12.6 hr; or 1.9 kg per day. This amount of condensation is on a par with commercial solar stills. 10 m2 of radiators cooling 50 W/m2 in humid air could produce 19 L of water per day.

People on average have a metabolic rate of 150 W. This is split between sensible heat and latent heat in the form of water vapor, the ratio depending on the ambient temperature. The load on the radiator to remove this heat requires at least 3 m2 at 50 W/m2. Net cooling in excess of this 150 W will reduce the temperature and humidity in the enclosure until it is balanced by heat leakage through the floor and walls.

POWER DISCUSSION

Factors:

1kw = 1.3 hp Water flow in cubic feet/second x height difference in feet divided by 8.8 = hp 1 cubic foot = 7.48 gallon Assume a two 10,000 gallon tank, one 100' higher than the other. To generate 1kw of power 1kw = 1.3hp = flow/second x 100 / 8.8 1.3 x 8.8 = flow x 100 11.44 = flow x 100 11.44 / 100 = flow .1144 cubic feet = flow .1144 cubic feet = .856 gallon/second 10,000 gallon tank / .856 = 11,682 seconds / 60 / 60 = 3.24 hours of operation for this "battery".

Given the above, consider a well where the water level is more than 100 feet below the surface. A surface tank could be the size of a modest “above ground” swimming pool. A small windmill could easily during the day fill the pool, providing the evenings power for light and electronics.

Moving water. Net head in feet times flow in U.S. gallons per minute = output in watts. In the family of impulse machines, the pelton is used for the lowest flows and highest heads. The cross-flow is used where flows are highest and heads are lowest. The turgo is used for intermediate conditions. Propeller (reaction) turbines can operate on as little as two feet of head. A turgo requires at least four feet and a pelton needs at least ten feet. These are only rough guidelines with overlap in applications. The cross-flow (impulse) turbine is the only machine that readily lends itself to user construction. They can be made in modular widths and variable nozzles can be used.

Most developed sites now use impulse turbines. These turbines are very simple and relatively cheap. As the stream flow varies, water flow to the turbine can be easily controlled by changing nozzle sizes or by using adjustable nozzles. In contrast, most small reaction turbines cannot be adjusted to accommodate variable water flow. Those that are adjustable are very expensive because of the movable guide vanes and blades they require. If sufficient water is not available for full operation of a reaction machine, performance suffers greatly.

An advantage of reaction machines is that they can use the full head available at a site. An impulse turbine must be mounted above the tailwater level and the effective head is measured down to the nozzle level. For the reaction turbine, the full available head is measured between the two water levels while the turbine can be mounted well above the level of the exiting water. This is possible because the "draft-tube" used with the machine recovers some of the pressure head after the water exits the turbine. This cone-shaped tube converts the velocity of the flowing water into pressure as it is decelerated by the draft tube’s increasing cross section. This creates suction on the underside of the runner.

Centrifugal pumps are sometimes used as practical substitutes for reaction turbines with good results. They can have high efficiency and are readily available (both new and used) at prices much lower than actual reaction turbines. However, it may be difficult to select the correct pump because data on its performance as a turbine are usually not available or are not straightforward.

Another type of generator used with micro hydro systems is the DC motor. Usually permanent magnet types are preferable. However, these have serious maintenance problems because the entire output passes through their carbon commutators and brushes. www.microhydropower.com As little as 100 gallons per minute (GPM) falling 10 feet through a pipe or 5 gallons per minute falling 200 feet through a pipe can supply enough power to comfortably run a small household.

Turning generators with "steam" engines (water and other medium, open and closed cycle) Power can be relatively constant and regulated by using the sun to heat a storage medium, such as water in an insulated tank, which then provides power at night.

In example, since closed cycle heat engines are driven by a difference in temperature, as the outdoors cools at night, and the contents of an insulated tank remain warm, the power available may actually increase. Light concentration can DRAMATICALLY increase available power. The "steam" can also be heated by growing, collecting, and burning bio fuels.

Open cycle. The working fluid, which is heated to the boiling point, is channeled to expand and push a contained piston or turbine, then vented to the atmosphere. The typical working fluid is water, which may in some locations be too scarce a resource to "waste" as steam. This engine design also "wastes" the energy used to heat the water up to the steam point.

Closed cycle. The working fluid, which is heated to the boiling point, is channeled to expand and push a contained piston or turbine, then routed to a condenser for cooling below the boiling point, and then pumped back into the heating chamber. In theory (Carnot) the efficiency of a heat engine is limited to nc = T1(hot gas temp) T2(cool gas temp) / T1.

Historically low temperature solar engines are operated using freon or butane, with temperatures of 80 C.  In a low technology situation though, it may be necessary to use only "natural" mediums. (Perhaps water in a closed system that operates partially in a vacuum, so that water boils at a lower temperature.)

Food for thought. As shown by the closed cycle engine, the useable work is done by the change of state from liquid to gas, not the rise in temperature to the boiling state. Open cycle engines (think of the old steam engines) lose ALL of this initial heating energy. Closed cycle engines retain a significant portion, but must still clearly cool the medium before re-injection to the vaporization chamber. Rather than directly using steam to turn a generator, I've wondered about using steam to pressurize a tank of water (insulated from the water some way?) then using the water to spin a micro hydro system.

THERMOCOUPLE Before solar cells existed, one way to make electricity was to connect a large number of thermocouples in series. This is called a thermopile. A thermocouple is made by joining two different types of wire together at the ends. If the ends are at different temperatures a current will flow through the wires. The current and voltage is very tiny, so you need to connect many hundreds or even thousands of thermocouples together to make enough electricity to light an LED (light emitting diode). Scrape about one centimetre of the ends of all of the wires until both ends are clean and shiny with no insulation or dirt. Take one wire of each metal, and twist them together at one end so that only the cleaned sections are connected. For thicker wires you will need both pairs of pliers-grab the wires together with one pair of pliers, about 12mm from the end, and twist the ends together with the other pair. Take another piece of copper wire and twist it onto the free end of the iron wire in the same way as the first piece. Use the multimeter on the low resistance scale to ensure good connections. If you can solder, you might want to solder the ends together for a good connection. Place the mug and glass side-by-side and bend the iron wire so that one end hangs into the mug and the other into the glass. Connect the meter to the free ends of the copper wires, and set it to the millivolts range. Fill the glass with water and ice, and the mug with boiling water, and you should get a small voltage reading on the multimeter. SOLAR PHOTO-VOLTAIC

Direct conversion of light to electricity. The present silicon crystal panels remain a "high tech" item to produce, are fragile, and essentially impossible to repair in a low-tech environment. Power is ONLY supplied when light shines directly on the panel. Light concentration is likely to overheat the panel, and cause it to "burn out". Estimating a 1/4 acre homestead of around 10,000 sq. ft., at around 1 kw per sq. yd, while in full sun the entire lot receives just over 1,000 kw of power. If covered with 10% efficient solar panels, you'd have 100 kw available during sun hours. (But, no space to grow plants.) Set aside 8,000 sq. ft. for your garden, and using 2,000 sq. ft. for power, with the 10% panels you have available the same 22 kw you do now, but only during sunny days. Remember the sun's changing path, combined with the panel putting out the greatest power when perpendicular to the sunlight, means you will probably want a "tracking" mount.

ESTIMATING THE SOLAR PATH

We found what seems to estimate the sun's path by making a "tool" out of a 3 x 5 card. Fold the card in half so that it's 3" x 2/12". Lay it in front of you, fold to the bottom. Starting from the lower left corner (point A), measure an angle up from the folded bottom equal to your latitude (we're using 32 degrees N) Draw the line, label the line sky axis, label the point where the line reaches the right edge point B, and label the lower triangle E. It may help to staple the sky axis, then fold it back and forth until the upper free ends can both hinge on the sky axis.

Go to the point B, where the sky axis meets the right side of the card. Now, up from the sky axis measure 23 ½ degrees, and draw the line from point B back to the left side of the card. Label this point C.

Turn the card over, fold still at the bottom. Start at the lower right corner (point A on the other side), and draw a line that is 23 ½ degrees up from the sky axis. It should touch the "top" of the card. Label it point D.

Fold the one side of the card where you see line A – D until the smaller triangle is 90 degrees to the folded card. Label the triangle Winter.

Holding triangle E, fold the side of the card where you see line B – C until the quadrilateral is 90 degrees to the folded card. Label the quadrilateral shape Summer.

Hold the card such that the original fold is level to the ground, and triangle E points true south.

As you "hinge" the upper objects left and right along the sky axis, the flat surfaces "winter" and "summer" appear to reasonably approximate keeping a flat collector perpendicular to the sun in the "extremes" of it's seasonal path changes.

True south / north can be found using a pole, vertical nail, etc., where the shadow falls on level ground. Mark the tip of the shadow regularly throughout the day. Where the shadow comes closest to the vertical object, draw a line to the object. That line is approximately true S / N.

LOW TECH SOLAR P/V

Low-tech p/v solar cell, presented to spark thinking. Various online locations (that come and go), and the book How to Build a Solar Cell That Really Works, by Walt Noon, describe making a p/v cell at home, using oxidized copper. While not as "efficient" as silicon, it should be possible to locate copper, and make the cell, even after a crash. The plans use the clear plastic top from a plastic CD jewel case as the window. Any clear substance, and lots of silicone to attach the pieces together and to insulate them from each other should work.

The first step is to make a cuprous oxide plate. Once approach is to cut a piece of copper sheeting, clean the copper sheet thoroughly, sandpaper or wire brush. Heat the cleaned and dried copper sheet on an electric stove burner on the highest setting.

As the copper heats and oxidizes it is eventually coated with a black black coating of cupric oxide, which is removed to reveal the useful cuprous oxide layer underneath.

Cuprous oxide is a semiconductor, though not as efficient as the silicone used in commercial p/v cells. .

You won't power bulbs or charge large batteries with this type of panel, but it is a minute amount of power, that can be continued to be used for a long time while the sun shines.

STEAM

Solar/steam micro hydro for power. Consider a large tank of water capable of withstanding modest pressure, not necessarily much about typical city water pressure. Could solar concentration then be used to generate steam in an insulated bladder, to push water thru a micro hydro generator into another water tank?

How about freon "steam"? Could you essentially take the concept of an electric motor and the compressor in a refrigerator, and instead use a small "steam" engine connected to a generator?

WIND

Steel Farm project (2007), windmills near Kingman, 15 planned, $1.5 million each, each generates 1 megawatt, so construction cost of $1.50 per watt, or $1,500 per kilowatt. If each kilowatt is sold at $.15, ignoring interest the construction cost is recovered in 10,000 hours of productive operation. (say 420 days of operation)

Vertical axis windmill. Even numbers of opposed arms, each holding flexible material sails. On the power side, the wide billows the sail open, pulling a cable to help hold the opposing sail closed as it moves to windward during rotation. A british design for a vertical axis windmill with two outside blades like unto an airplane wing, with a central vane almost like a football profile. The design supposedly allows both the suction side and the pressure side to use the wind.

SOLAR HEATING

Mother Earth Issue # 48 demonstrates use a structure's existing south-facing wall for the back of a solar heat collector. This design does not include heat storage, unless your structure wall is something such as concrete. Add vents at the top and bottom (with doors to close off during the night of course) and a modest blower, and you've got heat.

A grid framework on the south wall, to hold such glazing material as you select.

Clay/ceramics. What could be more “appropriate”, dig clay, add water, form, bake in a solar oven for high temperature parts.

Solar heating ENROI. Say a square foot of glass requires around 18,000 BTU to manufacture. Is it worth making, or should you burn the fuel to heat your home? Every hour that pane of glass is in the sun in your heat collector, it gathers around 340 BTU's.  It "pays" for itself in 52 hours of solar exposure.

Other solar devices. Israeli research has developed a relatively simple means which uses a parabolic mirror to concentrate sunlight onto a fiber optic cable, which then leads to a light scalpel, useable as a laser scalpel. Sunlight can be used to directly “pump up” a laser to firing power. It can heat dangerous compounds past the temperature where they separate into harmless atoms or compounds. Light can readily be manipulated by lenses or mirrors. Given a crashing infrastructure, my feeling is that shiny material is going to be easier to obtain than precision formulated and ground lenses. Take the simple fact that light reflects off a flat mirror at the same angle it strikes the mirror. Now envision many tiny mirrors rather than one large one. If the angle of adjacent mirrors are adjusted right, the light can all be reflected onto a single spot, or spread to provide diffuse illumination from a single bright beam. In sixth grade, once my daughter got the concept, she was able to use cardboard and mylar gift wrap to make an 8” wide parabolic curve, which concentrated on black plastic ½” irrigation hose melted the hose, but not before it proved that in minutes it raised the temperature of water flowing in the hose to past 114 degrees F. Her combination active / passive model took first place in a statewide “solar home” competition. PEDAL POWER

A person can generate four times more power (1/4 horsepower (hp) – 180 watt) by pedaling than by hand-cranking. At the rate of 1/4hp, continuous pedaling can be done for only short periods, about 10 minutes. However, pedaling at half this power (1/8 hp – 90 watt) can be sustained for around 60 minutes.

In history the treadle is the most common tool to use leg power, and still in use such as sewing machines. But the maximum output is less than 15 percent of what your could do using pedal operated cranks.

The main use of pedal power today is still for bicycling. There is a vital difference between pedaling a stationary device and pedaling a bicycle at the same power output. On a bicycle a lot of energy goes to overcome wind resistance. Because of the wind as long as hydrated the bicyclist is less subject to overheating, than when on a stationary device. In planning for a stationary human power supply, allow for some power to operate a fan.

PEDALING RATE & GEARS

Humans can produce more power--or the same amount of power for a longer time--if they pedal at a certain rate that varies from person to person. In general aim for 50 to 70 rpm, call it an average of 60 rpm. In devices such as a sewing machines the person provides speed changes without changing the gear ratio. For applications where the load varies, gears may be necessary to keep the human on their best “power curve” and keep the load moving.

A single chain going over two sprockets is very efficient--over 95 percent, even for unlubricated, worn, or dirty chains. The crank length is the distance between the center of the pedal-spindle and the crank axis; that is, it is the radius of the circle defined by each pedal as it turns. The normal crank on an adult's bicycle is 165 to 170 millimeters (mm) long. However, people remain able to produce near maximum power output at any crank length from between 165 and 180 mm, so long as they have a period to practice pedalling at the new length.

SHAPE OF CHAINWHEEL

Evidence from tests suggests that elliptical chainwheels with a relatively small degree of elongation--that is, with a ratio of major to minor axis of the chainwheel ellipse of no more than 1.1:1--do allow most a human to produce a little more power.

PEDALING POSITIONS

There are three common pedaling positions:

The first is the upright position used by the majority of cyclists around the world. In this position, the seat, or saddle, is located slightly behind where it would be if it were a seat, or vertically above the crank axis; the hand grips are placed so that the rider leans forward just slightly when pedaling. Tests have shown that subjects using this position are able to produce the most pedalling power when the top of the saddle is fixed at a distance 1.1 times the leg length to the pedal spindle at the pedal's lowest point.

The second position is the position used by riders of racing bicycles with dropped handlebars, when they are holding the upper parts of the bars. Their back is then at a forward lean of about 40 degrees from the vertical. Their saddle height requirements are similar to those of cyclists in the first position. (The position of the racing bicyclist who is trying to achieve maximum speed is not suitable for power production on a stationary device. Even racing bicyclists sometimes experience great pain after a long time in this position, and the position is unnecessary on a stationary device because there is no wind resistance to overcome.

The third position is the position used in modern semi-recumbent bicycles. In this seating position, the pedaling forces are countered by the lower back pushing into the seat (which is similar in construction to a lawn chair made of tubes and canvas). The arms and hands do not need to remain on the handlebars to perform this function, the way they usually do in the first two positions. They can remain relaxed, and free to guide the work that the pedaler is powering. The upper body too can remain relaxed, and the chest is in a position that makes breathing easier than when the pedaler bends forward. The major disadvantage of this position is that, since the pedaler's legs move forward from the body, it may be hard to position large, deep equipment like a lathe or saw so that it is in reach without being in the way. In almost all other respects, the semi-recumbent position is highly desirable, though not essential.

PEDAL POWER FOR TRANSPORTATION

The principal use of pedal power around the world is for the transportation of people and goods. A bicycle used by itself can carry a rider, plus 50 to 100 kilograms of goods in a front and-or rear carrier on the cross-bar, or on the rider's head.

Gas (and diesel) guzzlers will become rare. Non fossil fuel sources do not bode well for providing large quantities of cheap fuel. Solar electric breakthroughs promise to allow greatly increased hydrogen production, as does fusion if ever safely and fully developed.

Absent breakthroughs, the primary biofuels appear to be plant oils (diesel), and alcohol. Alcohol can be used by virtually every internal combustion engine with relatively minor modifications, as well as in developing "fuel cells". Some studies claim the plant "comfrey" may be the ideal fuel alcohol soil crop, with algae having potential for large scale production. Alcohol is a MUCH easier fuel to work with than hydrogen.

Pedal power, referred to as bicycles, but more properly human powered vehicles, can meet a great deal of local transportation needs. In terms of weight carried, speed and distance, per power used, a bicycle is the most efficient vehicle available. A typical adult on an upright bicycle should be able to maintain a sustained level road speed of 10 to 12 mph. The same person on a recumbent should achieve a higher sustained speed due to lower air resistance and the ability to provide a more efficient braced "push" on the pedals without also straining back, neck, arm, etc. muscles as is required on an upright bicycle.

Bike design, at least as "artwork", goes back further than you may think. Sketchbooks of Leonardo de Vinci, from around 1490, show what can clearly be interpreted as a pedal driven bike, similar to the layout of a traditional upright bike. There is no indication though that it was ever built, and in his day, a bike chain would have been a great challenge to make and maintain. Kirkpatrick MacMillan did, in 1830, have a functioning treadle driven design, no chain, but also no gears.

In a low-tech environment, the bicycle chain is possibly the most difficult part to make, followed by the bearings. (A bike chain can be 98% efficient at transmitting your pedal energy.)

While most bikes are made from cut and welded tubing (i.e. steel, aluminum, or titanium) they have also been made of wood, fiberglass, laminated sheet of metal, etc.

Mother Earth News Issue 81 had plans for a recumbent trike made from recycled parts. See the article for details.

The relatively recent "rediscovered" recumbent bicycles (dating at least back to 1933) are more efficient than the traditional, high seat bicycles. A bicycle of this type enclosed in a streamlined fairing has been pedaled at sustained speeds of over 65 mph - try THAT on your mountain bike... If you do your “shopping”, you can probably find a recumbent (new) for a price easily comparable to any “department store” traditional bicycle. (2003 I bought one new for $300, 2004 for just over $100) Even low power augmentation (i.e. electric motor) can make modest commutes continue to be practical individual endeavors.

Personal powered vehicles. The cost and complexity of batteries, fuel cells, etc. may keep personal vehicles from returning to anything approaching the widespread ownership and use of today's industrial nations, or at least from resembling a 20th century automobile.

In 2006 federal law classified bicycles with a electric motor of 750 watt or less, and not capable of traveling under power more than 20 mph, as NOT a motor vehicle.

In May 2006 the State of Arizona added to this definition, within the state, a bicycle with a fuel powered motor of 48 cc or less. Should you chose gas or electric? The issue of noise and pollution produced by a typical two-stroke gasoline engine (i.e. lawnmower) vs four-stroke (i.e. car engine) is potentially significant. The two-stroke gasoline engine generally puts out 10 times (more of some) as many pollutants per amount of fuel burned. The operation of these engines, in general, initiates and forcefully imposes upon others the fouled air and excess noise.

The two-stoke system is used because it provides the lightest fuel burning engine for the power produced, but paradoxically the two-stroke is significantly LESS fuel efficient than a four-stroke engine. The fuel in-efficiency of these engines leads to the pollution problem. But the pollution from these engines is not limited to transportation.

These engines are extensively used on lawnmowers, weed whackers, portable blowers, etc. I've read the California Air Resources Board has calculated that 2% of the smog generated by all engines originates from lawn mowers.

I don't have a gas mower, so I'm guessing, say a mower runs an hour per gallon of gas? As fuel prices rise and more people look for (the temporary assistance) of cheaper transportation, 100 mpg may sound attractive. But if the two-stroke "bike" gets 100 mpg, the pollution released in that distance (and one hour of mowing) is at least equal to burning 10 gallons in your car.

May 2006 Arizona law specifically exempted these gas bikes from emissions inspections. Not only would I suggest they SHOULD be required to meet emissions standards, I would suggest that ALL engines be required to meet equal standards. Pollution of our air, is pollution of our air, whether it comes from the tailpipe of a car, bus, truck, moped, or lawn mower.

A gallon of gas is somewhat equal to 36,700 watt/hour of electricity. The gasoline bike is said to get 120 mpg. At the legal top speed of 20 mph, it must burn gasoline equal to 305 watt/hour of electricity. With gasoline at $2.92 per gallon the two stroke bike costs just under 3/10 cent per mile. It's "advantage" is it can run for five hours.

So how does an electric bike compare with the gas model? The electric bike must have an engine less than 750 watt. It takes 3 minutes (for either bike) to travel a mile, so the electric bike uses 1/20 times 750 watt = 37.5 watt/hours to go a mile. Grid electricity costs 8 cents per 1,000 watt/hour. In running a mile, the electric bike needs 3.75% of a kilowatt hour, or about 3/10 of one cent of electricity.

Certainly for pollution avoidance, and cost per mile, my bet is that the electric bike. It can charged at home, i.e. from a solar panel. The electric bike "disadvantage" for the moment, with present batteries, is lack of range, and of course replacement of the batteries. The carrying capacity of a bicycle can be greatly increased by attaching a trailer to it. One model of trailer has seats for two adults, and allows the bicycle to be easily converted into a rickshaw.

A rickshaw is usually made from the front or rear-portion of a standard bicycle, connected to a load-carrying platform over a two-wheel axle. Rickshaws can carry an extraordinary quantity of people and goods. In Bangladesh, they are responsible for transporting several times the total freight and passengers carried by all railroads, trucks, and buses combined.

However, the potential productivity of these rickshaws is greatly reduced by the fact that virtually most have few gear options, and the INEFFICIENT upright pedaling position.

OXFAM, an international development and relief organization, has done considerable work on a three-wheeled pedal operated vehicle capable of carrying payloads of over 150 kilograms. Called an "Oxtrike," the vehicle uses a three-speed gearbox in its transmission and a mild steel sheet frame. The frame can be manufactured on a small scale, using foot-powered cutters, hand operated folding machines, and welding or riveting. It can be fitted with passenger seats or a cargo box.

Your ordinary bike is not strong enough for payloads beyond one person, nor are your brakes good enough.

Broadly speaking, applications of pedal power is practical when the power level required is below a quarter of a horsepower (that is, below about 200 watts). This works for mobile or stationary uses, including to generate electricity.

THE DYNAPOD

Bicycles can be adapted to provide power, but a specifically designed unit would be more efficient. They can be designed for one or multiple person pedaling.

MAKING FUEL Fuels. Portable devices need a portable supply of energy. Self propelled devices, in particular those for flight, need a lightweight, concentrated source. The simplest "fuel" to manufacture is Hydrogen, which allows a variable power source to be converted into on-demand electricity, heat, or propulsion. At atmospheric pressure, the energy content of hydrogen is 3watt hour per liter (290 BTU per cu. ft)  Typical electrolysis of water is at best 30 - 35% efficient, at 25C (77F). Some advanced cells with platinum electrodes are as efficient as 73%. There is no upper limit to current input, but production improvements for voltage increase is about 2 volts, with any excess going into the water as heat. Supposedly, home-made electrolyser's can be 50% efficient, i.e. a watt-hour of electricity can produce 1/2 watt hour of hydrogen. The amount of power needed decreases with rising cell temperature, which bodes well for simple heating of the water with reflected light. Strictly using temperature, water will split at 2,730C (4946F), the undeveloped means being the ability to separate the gases and collect them. But power needs increase with increased pressure, so there is a need to AVOID reaching the boiling point (unless the steam can then be split easier). A means to focus ONLY Ultraviolet (8% in sunlight) light, which is a frequency which water directly absorbs, and that in high concentrations can split water directly, has potential for efficiency increases. Some catalysts pose hope for minimizing the electric current needed. Special strains of algae, other plants, bacteria, etc. can of course split water and other compounds into hydrogen or hydrogen containing fuels.

BIOFUELS - VEGETABLE OIL YIELDS

Ascending order Crop	kg oil/ha	litres oil/ha	lbs oil/acre	USgal/acre corn (maize)	145	172	129	18 cashew nut	148	176	132	19 oats	183	217	163	23 lupine	195	232	175	25 kenaf	230	273	205	29 calendula	256	305	229	33 cotton	273	325	244	35 hemp	305	363	272	39 soybean	375	446	335	48 coffee	386	459	345	49 linseed (flax)	402	478	359	51 hazelnuts	405	482	362	51 euphorbia	440	524	393	56 pumpkin seed	449	534	401	57 coriander	450	536	402	57 mustard seed	481	572	430	61 camelina	490	583	438	62 sesame	585	696	522	74 safflower	655	779	585	83 rice	696	828	622	88 tung oil tree	790	940	705	100 sunflowers	800	952	714	102 cocoa (cacao)	863	1026	771	110 peanuts	890	1059	795	113 opium poppy	978	1163	873	124 rapeseed	1000	1190	893	127 olives	1019	1212	910	129 castor beans	1188	1413	1061	151 pecan nuts	1505	1791	1344	191 jojoba	1528	1818	1365	194 jatropha	1590	1892	1420	202 macadamia nuts	1887	2246	1685	240 brazil nuts	2010	2392	1795	255 avocado	2217	2638	1980	282 coconut	2260	2689	2018	287 oil palm	5000	5950	4465	635

DISTILLILNG ALCOHOL

In the concentrations available from natural processes, alcohol is oral sensory depressant. Once distilled in greater concentration it is also a disinfectant and fuel. In general within the U.S. if you distill alcohol you must pay a liquor tax on it, otherwise you are guilty of tax evasion.

A still is a means to utilize the fact that alcohol boils at 173 degrees F and water boils at 212. A natural alcohol solutions at a rolling boil is above that needed to vaporize alcohol, but with observation when the alcohol is gone the flow from the still will become a trickle of water, and you’re batch is done.

You need a sealed means to heat your mixture to a controlled temperature, cool and collect the alcohol vapors. A low volume low tech home still goes something like:

Stainless steel pressure cooker. Connect the pressure vent to about 10 feet of 3/8” copper tubing. If you are planning on coiling the tubing buy it already coiled in a box, otherwise bend it an inch or so at a time, an old story is to fill it with sand to minimize kinks.

You need to cool the alcohol to condensation within the 10 feet or so of tubing, which is why it is usually coiled and immersed in a vat of water.

The equipment can consist of a food dryer like mine, a Corona grain mill and a pressure cooker (unless you have a Kenmore water purifier from Sears). You will also need ten feet of 3/8 inch copper tubing, bought at most hardware stores for 50 cents a foot. The rest is just odds and ends you may have or can get at little cost.

CORN SQUEEZINGS

Sprouting turns most of the starch into sugars and diastase. The sugars are readily converted into alcohol by yeast while the diastase turns starch into more sugar. Immerse 2 pound of whole, non-hybrid corn in a clean vat of warm water for 24 hours, then drain. Flood with warm water once every 24 hours until you have plenty of sprouts of about ½ inch.

NOTE: You probably cannot buy non-hybrid corn at your local feed store. With hybrid only about 10% will sprout, leaving 90% a rotten mess. Rotted starch doesn't convert to alcohol. You may need to grow it yourself.

The fermenting container needs to hold almost three gallons, and be air-tight once filled. Look at three gallon “clear” water bottles. Drill and seal into a hole in the cap a thin hose to allow CO2 to escape (otherwise “boom”). Put the hose in a jar of water to monitor the bubbles. When the bubbles stop the fermenting is done.

Mash the sprouted grain. Boil two gallons of water and add the mash slowly. Cooking kills bacteria and helps break the starch molecules. After thirty or forty minutes, take the pot off the heat and put it in a dishpan of cold water to cool it down. It shouldn't have any lumps in it since that would cause uneven fermentation. If you have stirred it properly, there should not be any lumps. In case there are, break them up.

Weigh out 1/2 pound of sugar and put it in a measuring pitcher. Then add hot water until it reaches the quart mark. The sugar should cool it to a temperature safe for the yeast. If it feels warm but not hot, dump a package of active dry yeast (not fast-rising or acting yeast) into the sugar and warm water. Stir it with a fork until it dissolves. Then put a plate over the pitcher and let it alone for about an hour. It will be covered with froth. Stir it again.

Pour the mash into the container

If the mash is no longer hot, pour in the yeast and sugar and give the container a few sloshes.

Put the container in 85 or 90 degrees. The warmer it is within the safe limits, the faster it will work.

With the cap on firmly and the tube in the jar, the bubbles should appear in an hour or so. After a few days, they will slow down and finally stop. You do not need to filer the mash. You can fill the container and shake to make it easier to pour. The cooked mash isn't too inclined to stick. But it is a good idea to add water to completely fill the container when it is ready to distill and then to shake it well before pouring some into the still. Thus diluted the mash is pretty much in suspension so it won't stick or burn. Fill the pot only two-thirds full and keep the heat at Medium. When it heats up, the alcohol will come over in a fairly fast trickle. When the alcohol is all out you'll notice a decrease, indicating it is only water.

ELECTRICITY

Electricity is the flow of electrical force, NOT necessarily movement of electrons. Electrons do move, but an electron does not race along the powerline from the generator, to your home, and back to the generator 60 times per second.

A conductor is a material that readily allows electricity to flow along it, typically the metals, gold, silver, copper, aluminum. We must realize though that while general science and technology (2006) can utilize electricity, we do not clearly know what it "is".

An insulator is a material that generally does not allow electricity to flow along it, such as glass, plastic, rubber.

A circuit is a complete path for electricity to flow and return to the generating source.

Voltage is considered as a measure of the electromotive force, an analogy is water pressure in a hose.

Current is a measure of the amount of electricity flowing in a circuit, an analogy is the water volume flowing in a hose. DOWN THE ROAD Scientific experiments appear to confirm that in some manner, time slows at greater speeds. Whatever time actually is, tests show that chemical and even nuclear reactions proceed "slower" when the interacting objects are traveling at greater speeds. Science then tells us that since it takes more energy to cause a high speed particle to change direction, than a low speed one, that the particle has increased in mass. Supposedly, as the particle approached light speed, it would become infinitely massive, which is partially borne out by the increasing energy to cause change. However, mass has gravity. If a particle truely became infinitely massive, would it not become a mini-black hole, and at least suck-in the lab? If time slows for the particle, such that "instant" nuclear decay can take seconds, think instead that a seconds long push from a particle accelerator would only be "experienced" by the particle for a single instant. OVER UNITY DEVICES There are numerous claims of non-moving part wire and metal devices outputting far more power than put in. If any of these devices prove to be real, and capable of being constructed from simple parts from your neighborhood electronics store (or junk parts), we would have an incredible leap in available power. Don’t hold your breath though. Coler is attributed two such devices, one called a “Magnetstromapparat” [Magnet Power Apparatus] the other “Stromzeuger”, from which he claimed that with an input of a few watts from a dry battery an output of 6 kilowatts could be obtained indefinitely.

The device consists of six permanent magnets wound in a special way so that the circuit includes the magnet itself as well as the winding. These six magnet-coils are arranged in a hexagon and connected as shown in the diagram, in a circuit which includes two small condensers, a switch, and a pair of solenoidal coils, one sliding inside the other. The story is to bring the device into operation, the switch is left open, the magnets are moved slightly apart, and the sliding coil set into various positions, with a wait of several minutes between adjustments. The magnets are then separated still further, and the coils moved again. This process is repeated until at a critical separation of the magnets an indication appears on the voltmeter. The switch is now closed, and the procedure continued more slowly. The tension then builds up gradually to a maximum, and should then remain indefinitely. The greatest tension obtained was stated to be 12 volts. The device consists of an arrangement of magnets, flat coils, and copper plates, with a primary circuit energized by a small dry battery. The claim is the output from the secondary was used to light a bank of lamps and was claimed to be many time the original input, and to continue indefinitely.

FUSION In late 2006, Dr. Robert W. Bussard, formerly of the Atomic Energy Commission, announced online that his modest company had achieved controlled, sustained fusion, by the use of electrostatic fields, in a device that is simple, compared to the fusion experiments using magnetic "bottles". Dr. Bussard points out that the concept is not only relatively simple, it is not new. He refers to a paper on the topic published in 1924. He proposes an approach where the fusion process generates NO NEUTRONS or radiation, it does generate electrons and protons, that might be captured and converted in a shell to electricity at potential efficiency of 98%. Demonstration models of his device CAN be built at home, and they WILL produce fusion. His presentation and patents seem to indicate that a device, capable of powering a modern city, could be built with the resources of that city. His presentation also lends credence to other hydrogen claims, such as the atomic hydrogen torch. There are numerous claims that if hydrogen is passed thru a spark gap, then burned, it burns a great deal hotter than hydrogen so treated, well beyond any energy that could have been added by the electricity. It appears possible in theory that some hydrogen in the torch flame may be fusing and adding a great deal of heat. ELECTROSTATICS Much of present human technology is based on electro-magnetic devices. High school physics sets out the theory of electron shells, and the explanation of electron exchange for the interaction of elements. Electrical charge (think electrostatics) holds the electron "in orbit" of the proton, and molecules together. As Bussard’s presentation hints at, there is a great deal about electro-statics that we do NOT know. Sub atomic particles are sometimes said to "tunnel", that is they will be observed to essentially disappear from one location and reappear elsewhere, without having traveled in any known matter the space in between. A deeper thought though is whether the "particles" have any real position or motion, as we generally think of such.

Both the "strong" and "weak" nuclear forces are stronger than the electrical force, (say 100x) but their range is essentially limited to the scale of an atomic nucleus, while the range of the electrostatic force is NOT limited. There appears therefore to be a limit on how many protons can be held. If the diameter of the nucleus exceeds the strong force effective range, the attraction aspect of protons that are too distant "disappears" while the electrostatic repulsion of the "distant" protons remains.

SUB-ATOMIC CURIOUS ASPECTS

Combining a free electron and a free proton to form basic hydrogen (which happens naturally if they encounter each other) releases 51.06 ev, roughly 9 times the energy of "burning" hydrogen (combining hydrogen and oxygen), which releases 5.6 ev.

Combining two protons and two tlectrons releases 28 MILLION ev.

A vacuum appears to present factors as though it contained 2 BILLION TONS of mass per each cubic centimeter.