GlobalVillages: Arcology/EnergyProduction

Arcology /
Energy Production

For this topic we will consider energy production that is self-contained. The structure of the building and its subsystems will be an important part of the energy topic.

Conservation and passive building techniques

Active energy techniques

Biofuels

Alcohol
Biodiesel
Methane
Wood

Solar

PV - PhotoVoltaic
Thermal

->Radiant Heating and Cooling with water as the Medium Typically, large buildings with better surface to volume ratios tend to need cooling more than heating due to internal heat sources such as people, lighting, electronics and cooking. Night Sky Cooling uses emissive panels to release heat to the sky at night. The arcology core would need a mass storage system of water or structural elements to create a thermal fly-wheel. This system has many advantages over forced air or convective air cooling systems, and one disadvantage, potential leaks. Unlike passive convective air systems, a water based thermal distribution system can be used for both heating and cooling with equal ease.

PhytoTechnology - using photosynthesis

Wind

Good general overview of Alternative energy sources posted with the permission of Terry Kolk from andorprojex@yahoogroups.com

[+ENERGY PRODUCTION+] - tapping power

note: If you have already read the file on "energy conservation" (if not you should do so), you will know something about the need to conserve power while cooking, heating, cooling, and using electricity. Without a basic understanding of energy conservation, the following information will be without a foundation.

Here are some prime candidates for small-scale energy transformation:

SOLAR THERMAL - Sunlight contains an incredible amount of energy.

When sunlight falls on a dark surface, that surface heats up. Trapping sunlight, heating something up,\\ and storing that heat are what solar thermal is all about. Super insulated buildings can be heated by solar energy (as long as there is sunlight). Solar thermal systems can be divided into "passive" and "active". Passive systems have no moving parts. A black painted tank filled with water and exposed to sunlight is an example of a passive system. An active system has moving parts (blowers, pumps, valves, etc.). An example of an active system might be a rooftop mounted solar thermal panel filled with antifreeze (so that it does not freeze during the winter) that is connected to an indoor insulated water heater. There is a pump which pushes the antifreeze through a heat exchanger coil in the water heater (where the trapped solar heat is given over to the water) and back again to the rooftop solar thermal panel where it picks up more heat from the sun. Active systems tend to break down and should not be used where a passive system will suffice. Both active and passive systems can heat air, water, and even rock. Passively and actively heated solar building both use some sort of thermal storage system (water or rock) to trap excess solar heat and release it gradually over time, maintaining an even temperature indoors. Some people have even constructed solar thermal "heat engines" which turn sunlight into mechanical power to spin generators, pump water, and run drills,lathes, and fans.

SOLAR ELECTRIC - The proper term for this is called "photovoltaics" or PV. PV panels are composted of\\ PV cells. Several panels wired together make up a PV array. PV must be pointed at the sun. Power production is reduced when the sunlight strikes the cells at an angle.

PV cells are more efficient in cold weather. Commercial PV cells for home power production transform \\about 10% of the sunlight into electricity. There are experimental and NASA related PV cells which have a much higher efficiency but \\they are either very expensive or not yet available. Commercial PV cells are not cheap either but they do not make any noise or pollution while producing power. PV output is DC (direct current) and is usually stored in a battery bank. The battery bank can be tapped direct to provide power for pumps, electric motors, and compression cycle refrigeration (which run more efficiently on DC than AC). An "inverter" may also be connected to the battery bank to produce 120VAC (standard wall current) with about a 5-10% reduction in efficiency. Electric systems which are not connected to the grid are called "off grid" or "stand alone". PV systems may also be "grid intertied".

WIND POWER - Wind power can be either mechanical (like those old fashioned towers with the large bladed fans which were used on farms to pump water from wells) or electrical. Wind powered electric generators cost far less (watt per dollar) than PV systems and are hooked up to a battery bank just like PV. If there is a steady and strong source of wind, wind power is a good option. Wind machines need to be at least 50' above the ground. The closer to the ground (or house or trees) the more turbulence there is and the less power produced. The higher the tower the greater the chance of a lightning strike. Wind power works where there is wind and is a fairly efficient conversion of environmental energy.

WATER POWER - Microhydro units are used to tap flowing and falling water and convert that energy to electricity. Microhydro systems are hooked up just like PV and wind generators. If the flow and fall are strong and steady enough, microhydro is a great option for continuous power production. Another water trick is to use the falling water to turn a wheel to provide direct mechanical power to grind grain, spin fans, and power drills and lathes. A community with an abundance of falling water is lucky indeed!

EARTH POWER - Below the frost line, the earth is about 55 degrees F. Tubes or pipes can be laid through the earth and air or water pumped through those pipes. This is called "geothermal". During the summer this system can be used to cool a building. During the winter, this can be used with a "heat extractor" to provide space heating. If you are using a conventional propane or natural gas furnace or even a woodstove, the air used for combustion should come into the building through ground pipes, using the earth to preheat the air to 55 degrees F. When coupled with a solar thermal system, excess summer heat can be pumped/blown through these same pipes, heating the ground below the building and raising the ground temperature by a few degrees.

BIO-GAS - When organic animal and human wastes and garbage

decompose in anaerobic conditions (without oxygen) they produce a mixture of gasses which contain a high proportion of burnable methane. Home scale methane production does not work since we do not produce enough waste.

Community scale systems, especially if there are farm animals to provide manure, can be made to work. The gas is not very high quality and, when burned, does produce some pollution, similar to propane or natural gas. Natural gas is mainly methane.

BIO-DIESEL - By using emulsifying agents (usually chemicals) dirty ryer fats from restaurants can be recycled into bio-diesel and may be burned in diesel engines to run vehicles or even back-up electricity generators. Bio-diesel pollutes less than petroleum diesel fuel.

ALCOHOL - Alcohol (with the proper government permits) can be made from excess grain, wood chips, and sugars. It can be burned in most internal combustion engines with slight modifications to the carb and the replacement of plastic tubing with metal. Burning alcohol pollutes less than gasoline but still creates poisons which are normally exhausted into the atmosphere.

HYDROGEN - Hydrogen is burned with oxygen to produce heat and water vapor. There is no pollution in this reaction. When hydrogen is burned in open air there are some nitrogen oxides produced (very little).

Most internal combustion engines, gas stoves, gas dryers, and gas refrigerators can be converted to burn hydrogen. There is another way to "slow burn" hydrogen called "catalytic combustion" in which hydrogen is consumed without a flame at the surface of a rare metal catalyst like platinum. Some space heaters are "catalytic heaters". Another way to burn hydrogen is in a fuel cell. Fuel cells use a catalyst and a series of membranes to combine hydrogen with oxygen to produce heat, electricity, and distilled water. Small scale fuel cells are just coming into the consumer marketplace and may be even used to power vehicles without pollution. Hydrogen can be used to enrich bio-gas to make it a more usable power resource. The trouble with hydrogen is that it does not exist on earth in any appreciable quantity - except when it is bound to another element. Water contains 2 hydrogen atoms with 1 oxygen atom. The trouble is that it takes more energy to split water into H and O than the energy one gets by burning the two to create water! In other words, if you already have the energy to split water, why not use it direct? On the other hand, if you have excess energy (such as summer sunlight), why not use that energy to split water? The subject of splitting water and the methods of doing so are being studied in detail by experts and inventors all over the world in order to prepare the way for a "hydrogen economy" which some people believe will take over at the end of the fossil fuel era. I hope so. We should look deeply at this technology. It is a good candidate for Andor.

One more thing about hydrogen technology. When water comes in contact with radioactive substances, the water disassociates into hydrogen and oxygen. If this is run into a fuel cell, the fuel cell makes heat, electricity, and water. The water is then run back over the radioactive substance and the cycle continues. This is a "closed circuit system". If my sources are correct (the people who worked on this project), the Hubble space telescope has one of these closed systems on board. They call it a "99 year battery" because, every 99 years or so they must add a bit of water because, bit by bit, the water is converted to heat and electricity. There are many plans on the government and industrial drawing boards to use existing nuclear plants to make hydrogen for a "hydrogen economy". Personally, I believe the massive amounts of nuclear waste currently on earth could be used in small "home scale" units, wrapped in lead with an unbreakable titanium hull. A licensed service person would inject water every hundred years and replace the radioactive screens every thousand years or so. But, that's for the future. Right now this technology is not a viable option for Andor - mainly due to the LEGAL problems of working with nuclear waste.

I hope this short introduction has been useful to you. I left out some more esoteric energy production schemes (OTEC, tidal, wave motion, etc.) because they are not practical for a land-based sanctuary.

posted by Hank

Energy Links

Methane Digestors

http://journeytoforever.org/biofuel_library/MethaneDigesters/MDToC.html

http://journeytoforever.org/biofuel_library/MethaneDigesters/MDToC.htm l

http://www.green-trust.org/methane.htm

http://www.green-trust.org/2000/biofuel/methane.htm

http://www.new-agri.co.uk/03-3/develop/dev01.html

http://www.eren.doe.gov/consumerinfo/refbriefs/ab5.html

http://www.ce.ufl.edu/activities/waste/wddndx.html

http://www.biomasse-info.net/Englisch/biogas english.htm

http://www.biogas.ch/

http://www.undp.org/seed/energy/policy/ch_8.htm

What i seed emerging here is a knowledgebase that can be incorporated into a nice and very informative website. Needs some major pruning though. post by Jeff Buderer

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