Contents Introduction Chapter 1 Why are Earthships needed? Chapter 2 History of Earthships Chapter 3 The U-module 3.1 Configurations Chapter 4 Passive solar heating and cooling 4.1 Adaptation to climate and site Chapter 5 Domestic water systems Chapter 6 Waste water systems Chapter 7 Electricity Chapter 8 Integrated products Chapter 9 Aesthetics Chapter 10 Future Chapter 11 Tests on existing Earthships Bibliography Appendix I A building code for bearing and retaining walls made from earthrammed tires Appendix II Water use in a conventional home and in a water managed home

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Introduction This overview of what an Earthship is and how an Earthship works is written during an internship with Sustainable Communities Initiatives in Kinghorn, Scotland, from 03/05/03 until 15/06/03. An Earthship is a sustainable housing unit, built out of discarded automobile tyres and aluminium cans, that is self-sufficient, energizes itself, heats and cools itself, grows food and deals with its own waste. This internship is a part of Industrial Design Engineering at the University of Technology in Delft, Holland. All the information in this overview was found in the books on Earthships written by Michael Reynolds, the architect who developed Earthships. Note: where “south” is written, it means south in the Northern Hemisphere. It would be north in the Southern Hemisphere.

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Chapter 1

Why are Earthships needed?

Our housing today exists of compartments and a complicated web of piping and wires through which water and electricity are delivered to each compartment. We are dependent upon and vulnerable without these centralized systems. Existing housing is nonfunctional without systems. The systems give us power in one hand and poison in the other. The ever increasing webs of powerlines and pipes are dangerous, unhealthy, ugly and expensive. Acid rain, radioactive waste, polluted rivers and oceans and vanishing wildlife are all part of the ‘price’ for the life support systems necessary to make the current concept of housing functional. These systems are owned by corporations whose aims are not always in the best interest of the people or the planet. Centralized water systems are always dependent on the electrical systems. The network of piping in a cummunity or municipal water system is very costly both for installation and maintenance. These conventional systems also set us up for the unconscious and often accessive use of water from the aquifers. We spend tremendous amounts of time, energy and money transporting sewage to concentrated sites where we then attempt to treat it. Questionable water purification and treatment processes result in many areas in undrinkable water due to sewage, cattle urine, or radioactive waste. 80% of all waste water could be reusable as grey water. Today there are concerns about the quality of food. Much of this is due to the fact that food is produced and distributed for money as business. Possible economic, natural or human-made disasters could cut us off from electricity, water, sewage, gas and food. The major materials presently used for housing compartments have many factors that warrant some rethinking. Too much wood is used and although this is a renewable resource, trees need time to grow. Many materials are made in centralized areas and have to be shipped all over the country. Specific skills are required for the use of most materials, so unskilled people cannot use them. The manufacturing of materials consumes a lot of energy and much pollution is the result. Many new materials are unhealthy to be around. Unfortunately, this is not discovered until they have been used for years. Manufactured materials tend to dictate the nature of housing, whereas it should be vice versa. All things in nature contribute to the essence of nature by virtue of their being. Byproducts of one system are ‘fuel’ for another. The difference between nature and humanity is that we do not contribute. We tax nature while nature supports us. At some point we will tax nature to the point where it can no longer support us. We will find that we cannot support ourselves without nature. The number of people on this planet is still increasing. It is time for our methods of living to find the harmonics of the nature of the earth. Trees know these harmonics. That is why there are never too many trees. That which contributes to its surroundings in the world at large is constantly reinforcing the strength of its own existance. We need to evolve self-sufficient living units that are their own systems. These units must energize themselves, heat and cool themselves, grow food and deal with their own waste. The current concept of housing, in general, supported by massive centralized systems, is no longer appropriate, safe or reliable. We are now in need of Earthships – independent vessels – to sail on the seas of tomorrow. 4

Chapter 2

History of Earthships

The Earthship concept was developed by Michael Reynolds. He has experimented over the past thirty years in New Mexico with waste as a building material. Years of experimenting and improving building techniques resulted in the Earthship concept of today: a completely independent, sustainable housing unit, that generates its own electricity, heats and cools itself, catches rainwater, grows food and takes care of its own waste. The main structure is built with discarded automobile tyres rammed with earth and interior partition walls are built with aluminium beverage cans and cement. An important factor in the design of this housing unit is that the common person should be able to build it himself, without expertise or use of expensive machinery. Michael Reynolds wanted this sustainable housing unit to be accessible to the common person and designed it so that it can be built relatively cheaply. An Earthship can be built for a minimum of $20.00 per square foot. For a three bedroom house of 1600 square foot the minimum total building cost comes to $32000.00. Waste water plumbing in the Earthship is installed absolutely conventional and as per code. The waste water treatment system typically used in an Earthship is in addition to convention, allthough it has been proved to work without the conventional system. This “accomodation approach” is used so that the authorities can approve of Earthship building plans. At the moment more than 2000 Earthships have been built in countries all over the world. In his books Michael Reynolds describes the design, the building details and techniques needed to build your own Earthship. A special building code for bearing and retaining walls made from earth-rammed tyres has been developed to insure successful, safe and comfortable buildings (see appendix I). Solar Survival Architecture, Michael Reynolds business, specialises in the design and building of Earthships and typical Earthship products. Earthship Biotecture has developed three communities in Taos, New Mexico, to evolve and present sustainable housing. An Earthship forum and volunteerprojects inform people interested in building their own Earthship and offer situations for a hands-on learning experience. Through his books Michael Reynolds shares with us the latest innovations and on www.earthship.com additional information can be found on Earthships.

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Chapter 3

The U-module

An Earthship is built up out of a single or repeated module. This basic module can provide for the basic human needs of shelter, water, oxygen, food, temperature and energy. The module itself is an individual U-shaped space or room, with mass on three sides, glass on the fourth, and a skylight in the ceiling above the U of mass. Earth is bermed up on the outside of the mass walls for even more mass. Often the U shape is partially submerged as well. The module is actually constructed in two parts: the U (three mass walls) and the greenhouse (the glass wall). The mass U is the main living space for humans and the greenhouse is the main living space for plants. The greenhouse is always in the sun, whereas the U space has the potential of sun control. This module can be as small as anyone wants to build it, but it should not be deeper than 26 feet (spanning structural members longer than 18 feet are uncommon and expensive, so it is best not to make a U wider than 18 feet). The 26 foot dimension is as deep as the module can be and still be comfortably warm. The module cannot be expanded to make a house, but must be multiplied. A house is therefore a collection of modules, strategically placed in relation to each other and the site. The U-module is built with discarded automobile tyres rammed with earth. The massive walls of the Earthship are 2’-8” thick, which is wide enough to evenly distribute the loads over the earth upon which it sets. These thick mass bearing walls hold thermal mass and are their own foundations. The bottom of the mass wall will be well below the frost line and there is no danger of thermal movement. Earthships are built out of earth on stable, undisturbed earth. The design is not meant to resist the earth, but to join it. Although the north wall, or rear of the “U” is not necessary to support the roof, it is needed to retain the weight of the burying up against the building. The ability of this wall to retain the earth is strengthened if the wall is arched. This arch should be a minimum of 12” deep and can be as round as a semi-circle. Interior partition walls are build with aluminium beverage cans and cement. The cans act as spacers, the matrix of cement gives the wall its structural strength. The roof structure is usually built with wood, but a dome built entirely with cans and cement has been developed to replace the wood for the roofstructure. Another efficient room structure for earth rammed tyre construction is the circle Hut Module.

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3.1

Configurations

Straight row U’s can be constructed right next to each other with exactly the same solar orientation, and sharing a common mass wall. The greenhouse then becomes a hallway. The greenhouse can be closed off from some U’s while remaining open to others.

Staggered row Individual U’s can be stepped back from one another without causing shadows on the glass of the adjacent U’s. The space generated between the U’s can become a very thick mass wall, or an indirectly heated utility space. The greenhouse is again the circulation hallway, connecting the simple U modules.

Straight step Two U’s can be put one behind and above the other, stepping on the slope. A sloping site is necessary for this kind of combination. The most economical approach to this is to maintain the generic section and just repeat it. The easiest way is to place the upper level greenhouse wall over the lower level north wall. Many U’s can be combined in this way, creating a square grid of U’s, in plan, that step up the slope. The ‘greenhouse / hallway / heating duct’ still functions as in the previous examples. There can be an overlap between steps, creating a space in the middle that is two stories high inside. Fruit and nut trees could grow inside. There is significant heat loss though and need for shading in most cases. Upper rooms overlooking two story spaces tend to be warmer than the two story space. Staggered step When U’s are combined like steps, the number and size of U’s in each row may vary. This allows a series of different U arrangements stepping up a hill.

Combined step and row

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When stepping patterns are multiplied, they are actually combined steps and rows. Any single-level house plan can be designed and superimposed on a sloping site in steps.

Chapter 4

Passive solar heating and cooling

A combination of thick thermal walls, solar orientation and tapping into the thermal constant of the earth creates a year round stable, comfortable temperature inside an Earthship. An Earthship has glazing on the southside (when thermal priority is getting enough heat through the winter) positioned in such a way that most sunlight enters the Earthship throughout the year. The glass is positioned at an angle to be perpendicular to the sun at its low point (perpendicular to the angle of the winter solstice sun). This reduces reflection to a minimum in winter when heat is needed. If any parts are to be pulled forward from other segments, they should relate to the winter azimuth angle, so as to not create any shadows that would block solar gain. There should be no obstructions that might block the low winter sun, other than a tree that looses its leaves in winter. The cool mass of the walls will absorb the sun’s heat, but when the sun goes down and the air in the room cools, the heat will slowly be drawn back out of the walls. The perfect wall for a shelter that embodies energy incorporates both mass and insulation. Thermal mass on the the inside “captures” the desired temperature from any source. Insulation on the outside keeps the desired interior temperature from escaping and separates it from outside temperature. Temperature stored in the interior dense mass stabilizes the temperature of the living space creating comfort in that space. The most economical option is to use strawbales as an insulating material on the outside of the tyre walls. Four feet below the surface, below the frost line, the ground temperature remains remarkably constant, usually between 55° and 60° F. The Earthship taps into this natural thermal constant and remains consistently comfortable. A sunken garden may need to be dug in front of a submerged Earthship so that desired sunlight is not blocked. Earthships have a high operable skylight and a low window in each room to allow warm air to escape and cool air to be drawn in. This also allows individual air movement control in each room. Even when the hot sun is ‘charging up’ the mass, enough natural ventilation can be allowed to keep the space comfortable and full of fresh air. The entry is best on the East or West end wall, with an airlock / vestibule / mudroom. The airlock helps to prevent heated air from escaping whenever the door is opened. The living space of each U can be separated from the heating duct / greenhouse / hallway by hanging simple cloth or paper rolling shades, shading the space behind. Insulating shades can also be hung directly behind the greenhouse glass to shade the living space and cut down on heat loss at night. A dividing mass wall can be built between the mass U and the greenhouse. This can give more shade and privacy, but is not always necessary and is an added expence. It does improve the performance by holding heat in the U and cutting down on heat loss at night. This mass wall usually has glass above it to allow ‘borrowed light’ to come through the green house to the U. Freestanding closets or planters can give shade and can subdivide space within a U to have areas of added privacy. The solar orientation of the Earthship makes year round growing of edible plants possible in its interior space. The solar orientation of the Earthship also fills the livingspaces with natural sunlight, which reduces the need for artificial electrical light. 4.1

Adaptation to climate and site

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The high performance generic U module is designed for 100 degree summers and below zero winters in a generally arid climate (10” total precipitation per year) with reasonably stable soil. The use of the Earthship concept in other climates requires some tailoring to site and climatic specifics. Cold climate Glazing faces south, at an angle perpendicular to the angle of the winter solstice sun. In the more northern latitudes vertical glass provides maximum solar gain, since the winter sun is lower in the sky here. The southern latitudes have a higher winter sun, so here sloped glazing will maximize solar gain. Only high altitudes in these areas get cold enough to require the sloped glass. Other lower altitude, milder areas of southern latitude use vertical glazing. Insulation protects the structure from the earth until it gets below the frost line. Insulation is doubled on the ceiling, where heatloss is greater. Insulated shades can be installed on the glass to block heat loss at night. Very linear layouts east to west admit solar gain in every space. In climates with hot summers an overhang can be added to prevent summer sun from entering the space. In very cold climates smaller spaces with low ceilings result in more mass relative to the volume of air space, so the interior temperature can be stabilized. Increased east/west width and decreased north/south depth of rooms optimize solar gain. In extremely cold climates a secondary greenhouse may be added to create a buffer space between the living spaces and the extreme cold outside. The roof of the greenhouse matches the angle of the winter solstice sun. Very cold climates sometimes require insulation under the floor or a surface building to isolate the thermal mass of the shelter from the cool earth that is subject to frost line temperatures. Hot climate Glazing faces north, so no solar gain is admitted. Glazing is insulated to prevent outside air temperature to come through the glazing. Insulation is doubled on the roof to prevent heat gain from the sun. The roof should also have a light colour to reflect the sun’s heat. For ventilation fresh air is admitted low on one end of the space and warm air is released at the opposite end through high operable skylights. Since no solar gain is required floor plans can have more conventional layouts. In very hot climates roof insultion is maximum (R80). In very hot climates small spaces with higher ceilings result in more mass per volume of air space, so the interior temperature can be stabilized. The high ceiling allows the heat to rise up, at floor level it will be cooler. In very hot climates the incoming air for ventilation is taken through tubes recessed deep in the earth to absorb the earth’s cooler temperature before coming into the shelter. In humid climates the moisture in the hot incoming air tends to condense on the sides of the tube that are against the cool earth. This results in a natural dehumidifying effect before the air enters the space. In extreme heat cases, the skylight can be solar enhanced to facilitate better convection. A double glass wall creates a buffer zone that reduces heat gain from outside temperatures.

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High water table Sites where either stone or a high water table prevent the recessing of the building into the Earth have the thermal shelter placed on the Earth with insulation all around. Earth is built up around the building as much as possible to create burial mass. Plastic vapor barriers wrap a raised building pad. A plastic skirt surrounds the building just below finish burial. In a cold climate with a high water table perimeter insulation isolates the interior mass from the damp cold earth down to about five feet below burial. Some situations such as a sandy beach or a site near a stream that could swell would require a concrete foundation to elevate the structure above ground like any other building. In this situation you may not bury at all so a vertical rear wall can be used with rigid insulation and plaster. An arc is necessary in the rear wall if it is not buried. Deep water table The building is recessed into the earth as much as possible to connect with the cool earth. There is no insulation between the building and the earth. Unstable soil When the soil on the buildingsite is unstable earth cliffs can not be used. Excavation is still possible, but the tyres have to start on the bottom of this excavation, i.e. all the way down to floor level. Earthquake zones On a site where earthquakes occur concrete columns on the ends and corners of the tyre walls are needed. These concrete columns are reinforced with rebar and connect to a concrete bond beam.

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Hurricane zones In the Hurricane Home the U’s face in toward each other so the buried back walls face out to the wind. Large skylights accommodate the central greenhouse area. Usually hurricanes occur in hot damp climates where solar gain is not required. It is more important to cool the structure than to heat it. Because of the wet climate the building would most often be placed on the ground. Completely protected against wind damage, solar panels for power are in a telescopic pipe to be lowered flat on the roof during high winds. Chapter 5

Domestic water systems

Solar well A conventional well can be pumped into a storage cistern continuously and slowly all day long (while the sun is out) by a small solar powered DC pump. On a sloped building site water can be solar pumped from the well into a storage cistern placed up the hill from the Earthship and gravity provides pressure and delivery of the water to the dwelling. Watercatches Roof run-off and/or hillside run-off can be caught in a reservoir or cistern. The reservoir or cistern is positioned higher than the plumbing; gravity collects and delivers the water. Reservoirs that catch ground surface run-off need silt catches to trap dirt and gravel from the water. One way is to build a small dam with rocks on top in front of the cistern with a small pool behind it. The water overflows into the cistern after most particles have settled to the bottom of the silt catch, the rocks filter out particles floating on top. Another method filters the water through rock barriers ranging from large boulders to gravel on the way to the cistern. Outdoor cisterns still get some debris on top and silt on the bottom, even with silt catchers. It can also have a layer of ice on ther surface. Because of this a ‘floating intake’ is necessary: the flexible intake pipe is suspended to the desired distance below the surface and above the bottom. To cover the water reservoir during the freezing winter months insulated floating spa covers can be used or a structure can be built over the reservoir, used as a humid growing space. Roof catches In areas with reasonable rainfall, at least 10” of precipitation per year, the roof alone collects enough water. This is much easier and more economical than collecting ground surface runoff. Water is caught from roof catchment systems and channeled via silt catches into cisterns. Roofs are extended in arid climates so that more water can be caught. Roofs are primarily south facing in cold climates to allow snow to melt before it evaporates allowing more water to be caught. Greater flexibility in design is possible in locations with no winter. The materials that can be used are metal, cement plaster coated with potable coatings, and rubber. Only certain brands of metal are good for lead-free water. Torrential rains can often over tax even an industrial sized gutter and loss of water is the result. A more expensive but more efficient solar and water catch design for a sustainable shelter is a roof that is a basin for catching water, with a ‘kick up’ on the south side matching the lowest sun angle. 11

Silt catch and cistern A very large silt catch is needed for a preliminary clean up of the water, that does not overflow during torrential rains. The silt catch is the roof of the cistern. Water collects in the giant funnel roof of the cistern and overflows into the 8” diameter pipe in the middle. The pumice around the pipe captures most of the silt and dust in the water. The funnel roof is not insulated. This results in a temperature difference between the warmer mass of water inside the cistern and the cooler air temperature outside the cistern. This results in the forming of serious condensation on the underside of the funnel. The condensation is caught in a small trough at the bottom of the inlet pipe. Water caught in the trough is piped inside the building to a container for use as distilled drinking water. The cistern can be made of plastic, metal, cement or a pounded structural tyre circle plastered inside with cement plaster.

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Interior cistern Interior cisterns add humidity to the air in dry climates. For the purpose of aerating the water, waterfalls are a standard feature with interior cisterns, which provides a pleasant sight and sound aesthetic. The roof drains directly into an interior reservoir, which avoids the considerable expenses of pipes and funnels to get the water from the roof to the outside reservoir and which avoids ice dams and snow blockage. The only disadvantage is that some space is required in the building for the reservoir. An easy indoor cistern is made by digging into the ground, 5’-0” from floor level and building up 3’-0” from floor level with a can wall, plastered with a 5 coat cement plaster. The water is funneled into the cistern from the roof via “crickets”: added planes on the roof surface that slope water in a specific direction. The reservoir must have one 4” overflow for every 6” inlet. The roof must have one 6” inlet for every 1200 square feet of roof surface. The six inch inlet from the roof drain is covered with a screen to hold in some fine gravel as a preliminary filter to keep particles from flowing into the reservoir. Sometimes a particle pool is incorporated to allow particles to settle and be caught before the water tumbles down the waterfall. The water in the interior reservoir is circulated regularly, so it is kept fresh, by a small DC pump hooked directly to a 60 Watt solar photo-voltaic panel. The water is now circulated whenever the sun is out. This is independent of the house power. Hot water Hot water in catch water systems is obtained from selfcontained solar water heaters, gas on demand water heaters or a combination of the two. Chapter 6

Waste water systems

Water consumption is cut for individual homes by 75% in a catch water/contained sewage system, used in an Earthship, and no contamination occurs. In a watermanaged home one could live very comfortably with the use of 19.3 gallons of water per capita per day, rather than the 83.9 gallons of water used per capita per day in a conventional home (for calculation see appendix II). The waste water treatment typically used in Earthships is based on the natural wetlands concept, with the difference that the water is treated inside the building in a smaller area, so plant activity can have a year round effect toward cleaning water in homes built in areas with cold winters. This waste water system eliminates the need for public sewage systems and un-contained septic systems while getting multiple uses out of all water collected in the catchment systems. Household water uses may be presented in two categories: fresh water and grey water. Fresh water uses are: bathing, drinking, cooking, washing dishes, etc. Grey water uses are: food and flower growth, landscape maintenance and flush toilet use.

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Indoor grey water treatment / outdoor black water treatment system

The path of water in a conventional sewage system that can become a quadruple use grey water recovery system with the turning of two valves: 1. Water from rain and snow melt is caught on specifically designed roof structures. 2. Roof configurations direct water through silt catching devices and into cisterns. 3. Cisterns are positioned to gravity feed a pump and filter panel, called the Water Organizing Module (W.O.M.), including a drinking filter that filters out bacteria. Water is pushed by the pump into a conventional pressure tank and through the filters and household water pressure with soft, filtered rain water is the result. 4. This fresh rainwater is used by the home owner for any household use except flushing toilets. 5. Waste water (grey water) is directed into a grease and particle filter and then through a 30” deep interior rubber lined planter. 6. Oxygenation, filtration, transpiration and bacteria encounter takes place in the planter 7. At the low end of the planter water is directed through a peatmoss/charcoal filter and then recollected in a small well. 8. This twice used water is pumped from the well to flush a conventional toilet. 9. The toilet water (black water) is delivered to a solar enhanced septic tank (called an incubator). 10. Water goes from the solar septic tank into rubber lined, exterior landscaping planters set up very similar to the interior planter. 11. The system is valved so that all waste water can have the option of flowing into the septic tank. The septic overflow is valved so that all waste water can go into a conventional drainfield rather than the rubber lined exterior planters. The kitchen sink, washing machine, and tub/shower are the three largest producers of grey water. These fixtures should be split up in some way so that all three do not go into one treatment planter. 20 feet of planter is suggested per plumbing fixture as a minimum size. Indoor contained greywater absorbing tank Health officials will generally not approve of any grey water going outside the dwelling on the surface of the ground no matter how well kept the planter is. This means grey water needs to be delt with totally inside a closed system – nothing leaves the dwelling. This and the need for more space for food production are reasons for an indoor contained greywater absorbing tank that can support a virtual jungle. The toilet used in combination with this system is a solar toilet (see chapter 8), so there is no black water in this system. All the grey water is now contained and used in the building to produce food and flora. No waste water leaves the building. A well and stand pipe provide access to treated water for outside or inside use. The jungle room can be used as study, living area or even a bedroom. Chapter 7

Electricity

Earthships are powered by photo-votaic panels and sometimes additional wind or water turbines are used. Earthships are not connected to the conventional power grid, which means an Earthship could be built anywhere, on an island, on a mountain or in the desert.

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The owner of a solar powered home should carefully select which electric appliances he/she really needs and purchase the ones that are OFF when they are not being used. The Power Organizing Module (P.O.M.) typically used in Earthships is developed and manufactured by Solar Survival Architecture and is up to the latest code and made with all UL approved components. The system is developed so that any typical electrician can wire the house absolutely conventionally. The basic P.O.M. has eight 51 Watt photo-voltaic panels and ten 6 Volt batteries, and can be expended to 12 panels. This basic unit has proven itself to provide ample power for a household of 2 or 3 people. For slightly larger Earthships (2 bedroom, 4 people) a unit that can be expanded to 16 panels and 14 batteries is available. A very large Earthship would use a series of these simple power modules to avoid the costly, custom designed, hard to understand and maintain systems of the past. The best position in the Earthship for the P.O.M. and batterybox is behind the bathroom, which is usually positioned behind the south glazing for temperature reasons. The bathroom creates a shaded area behind it. The P.O.M. is secured onto a wall with the batteries below and the photo-voltaic panels above. It is recommended that the batteries are sunken into the floor for more protection. The battery box is detailed as a ‘vault’ with a 3 hour fire rating and has a high and low vent to sweep battery gases out. The process of changing D.C. electricity to A.C. electricity results in a loss of about 10% of the energy. For this reason lights are recommended to be on D.C. Power and outlets on A.C. power, since there are many D.C. lights available on the market today. If the inverter malfunctions, the lights would still work. Chapter 8

Integrated products

Thermal mass refrigerator Refrigerators monopolize 2 to 4 photo-voltaic panels year round. The most critical time for this constant draw of electricity is the winter, when days are short and sunlight is at a minimum. This is also the time when lights are used more often due to earlier darkness. The thermal mass refrigerator would work year round at any place that has freezing temperatures at night 90% of the time. In over half of the globe this concept could suffice without auxiliary power 50% of the time. This reduces the usage of power and takes the winter strain off of P.V. power systems. The thermal mass refrigerator unit must be placed out of the winter sun angle. Cold is admitted from the roof (as cold air is heavier and falls down) and stored in mass . The night temperature is allowed into the mass lined and insulated refrigerator space. This space is closed off during the day time and the mass enables it to retain the cold night temperature through the day. The range of use of this concept can be expanded by attaching a small DC cooling unit, run by P.V.panels. The entire unit is surrounded by mass and insulation. The higher the ceiling the farther the air has to travel, thus lower ceilings are better. The duct has a standard Earthship gravity skylight above. An insulated slide out damper is used to close the duct off from the cooled space during times when cool air is not coming in and it is better to contain the cool air that is allready there. This damper is also used when the DC refrigeration unit is the source of cool air. The unit is a freezer space on top with a cooling space on the bottom. The cooling space can be about 2’-0” tall while the freezer space is about 12” tall. A 5” mass divider between the refrigerator and freezer is made of sheet metal and filled with aluminium cans of cheap beer. The freezer mass is connected to the refrigerator mass and consequently conducts the cold temperature into the lower compartment, thus cooling (not freezing that area). The mass buffer between the two compartments also aids in containing the freezing temperatures while conducting cold temperatures. When there is a duct coming out the bottom to the outside, the cold air is pulled all the way through the unit and creates a constant flow of fresh cold air. This achieves temperatures as 15

cold as the outside. This “through air” duct can double as a fresh air duct for a nearby fireplace. It is sucked out through the fireplace chimney providing combustion air for the fireplace. Whenever you burn a fire, you are cooling your refrigerator and storing cold for the next day. Solar toilet The solar toilet concept is a cross between a solar oven and a compost toilet. It uses no water and no electricity. The excrement goes into a basket that holds the solids and lets the liquid drip through. This basket is placed against the solar front face of the Earthship in a black insulated space similar to a solar oven. Extreme temperatures (200 to 400 degrees) and direct sun simply fry the solids and evaporate the liquids. The fried solids turn to black ash and fall through the basket into a pull-out tray where it almost turns to dust. This tray is emptied once a month. Regular toilet paper can be used. It simply dries up and turns to flakes, then dust. The toilet vents like a wood stove and requires a scraper to be moved back and forth once a day. The first working prototype was the scraper model. One drawback was that you could see the fecal matter through the glass. A tumbler model has now been evolved, which contains the contents in a steel tumbler drum, so you don’t see anything through the glass or the seat. On this tumbler model the door opening that allows the tray to be removed is on the inside. The tumbler model works much the same as a composter when the sun is not out. Then when the sun comes out it fries the back

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tumbled compost. Both units require a DC fan, which is only turned on during use and kept off the rest of the time in order to maintain high temperatures in the “oven”. Both units are designed to fit into the front face of an Earthship. Different geographic locations would require different glass angles similar to the Earthship itself. The scraper model is best for areas with 200 or more sun days per year and the tumbler model will extend the use to areas with 150 sun days per year. Optional reflectors will enhance the performance of either model. Solar oven The solar oven is somewhat larger than a regular gas or electric oven. It has been developed to function as an oven and as a distiller. This unit is only effective in or near the sunbelt. Two hundred or more sun days a year would make this unit a feasible appliance for an Earthship. No vent pipe is necessary in the oven. The unit must be installed on the solar front face of the Earthship. A brick liner holds heat and creates a very slow cool down situation. A dinner dish can be cooked in late afternoon and remain “on warm” until dinner time. Standard fire brick (painted black) is placed in the oven after the oven is installed into the home. The water distilling unit can be placed in the oven when it is not used for cooking. The distiller/oven comes with a drain pipe on the side. The distilling unit fits onto the opening of this pipe. Water evaporates up from the water chamber, hits the stainless steel plate and runs into the collection tube. This tube directs the distilled water to the drain pipe. A container can be put under this pipe outlet and the distilled water will fill the container on a sunny day.

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Chapter 9

Aesthetics

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Chapter 10

Future

In the future the Earthship concept could be applied to city housing units. A superstructure built of concrete could be used in areas close to the city core. A little farther from the city core man made south facing mountain slopes could be created out of compacted earth, with less density and slope than the suggested concrete structure. This configuration would accommodate a colony of Earthships that step up the hill. If this land configuration were available in urban areas it would invite the application of urban Earthships by both individuals and developers.

Chapter 11

Tests on existing Earthships

The durability of tyres filled with earth can not be surpassed. A buried tyre will virtually last forever. The only thing that deteriorates rubber tyres is sunlight or fire. Tyres only burn when surrounded by air. Since they are filled with earth and buried, there is no danger of deterioration or fire. An Earthship was caught in a forest fire in New Mexico in 1996. Everything except the tyre walls and the aluminium can / cement walls was destroyed. The structure of the building was still usable and a new roof and front face have been installed. Recent research by the University of Winsconsin-Madison, regarding the use of scrap tyres in civil and environmental construction, indicated that shredded tyres do not show any likelihood of being a hazardous waste material or of having adverse effects on ground water quality. The hundreds of people who have lived in tyre buildings over the past 25 years have not reported any complaints about the quality of life. In fact the reports are to the contrary. People love the ‘feeling’ of these massive earthen homes. Tests on the waste water that has been filtered by an Earthship treatment planter have proved that the water is cleaner than recommended for water that goes back into the environment. A New Mexico recommendation is 30 to 50 mill. per liter of chemical oxygen demand and 20 milligrams per liter of ammonia nitrate for effluent going back into the environment. Mature, one year old systems test better than new systems due to the amount and length of plant roots. Water containing ashes from the solar toilet has also been tested. The tests showed no bacteria in the water.

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Bibliography 1. Reynolds M.E. Earthship volume I How to build your own Taos, New Mexico Solar Survival Press 1990

8. Reynolds M.E. Alternative water management Earthship Chronicles Taos, New Mexico Solar Survival Architecture 2000

2. Reynolds M.E. Earthship volume II Systems and components Taos, New Mexico Solar Survival Press 1991 3. Reynolds M.E. Earthship volume III Evolution beyond economics Taos, New Mexico Solar Survival Press 1996 4. Reynolds M.E. Comfort in any climate Taos, New Mexico Solar Survival Press 2000 5. Reynolds M.E. Packaged Earthship Plan option book Taos, New Mexico Solar Survival Architecture 1998 6. Reynolds M.E. Grey water Containment, treatment and distribution systems Earthship Chronicles Taos, New Mexico Solar Survival Architecture 1998 7. Reynolds M.E. Catch water Earthship Chronicles Taos, New Mexico Solar Survival Architecture 1998

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Appendix I

A building code for bearing and retaining walls made from earth-rammed tires

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Appendix II

Water use in a conventional home and in a water managed home

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