following reference material may be of interest to those participating in the
The Earthship was designed as a structure that would exist in harmony with its environment and be freed from the constraints of modern shelters which rely on centralized utilities. It is important that the Earthship creates its own utilities as well as uses readily available and sustainable materials. In order to be entirely self-sufficient the Earthship needs to be able to handle the three systems of water, electricity, and climate (heating & cooling). While these systems are not exclusive to Earthships, a properly designed Earthship must have these systems.
Earthships are designed to catch and use water from the local environment without bringing in water from a centralized source. Water used in an Earthship is harvested from rain, snow and condensation. As water collects on the roof it is channelled through a silt-catching device and into a cistern. The cisterns are positioned so they gravity-feed a WOM (water organization module), that filters out bacteria and contaminants, and makes it suitable for drinking. The WOM consists of filters and a DC-pump that are screwed into a panel. Water is then pushed into a conventional pressure tank to create common household water pressure. Water collected in this fashion is used for any household activity except flushing toilets the conventional way. Rather, the water used for flushing toilets has been used at least once already: frequently it is filtered waste-water from sinks and showers, and described as "Grey water".
Grey water, water that has been used and is unsuitable for drinking, is used within the Earthship for a multitude of purposes once it is reclaimed. First, before the grey water can be reused, it is channeled through a grease and particle filter/digester and into a 30”-60" deep rubber-linedbotanical cell, a miniature living machine, within the Earthship. This filter with imbedded plants can potentially also be used to produce food (for example, by using a fruit tree). Oxygenation, filtration, transpiration, and bacteria-encounter all take place within the cell and help to cleanse the water (Reynolds 2000). Within the botanical cell, filtration is achieved by passing the water through a mixture of gravel and plant roots. Because of the nature of plants, oxygen is added to the water as it filters, while nitrogen is removed. Water taken up through the plants and transpired at their tops helps to humidify the air. In the cell, bacteria will naturally grow and help to cleanse the water.
Water from the low end of the botanical cell is then directed through a peat-moss filter and collected in a reservoir or well. This reclaimed water is then passed once more through a grey water board and used to flush conventional toilets.
Often, any grey water that is made at Earthships is not polluted enough to justify treatment (its "pollution" being usually just soap, which is often not environmentally damaging). At Earthships, the use of plants placed at outlets of fixtures is then practiced to regain the water and the nutrients lost (e.g. from the soaps). Usually, a single plant is placed directly in front of the pipe, but mini drain-fields are also sometimes used. The pipe is made large enough (5,08 cm) so that the formation of underground gas (from the grey water) is avoided. This is done with kitchen and bathroom sinks, and even showers, washing machines, and dishwashing machines. The plants are usually placed indoors with the sinks and outdoors with the washing/dishwashing machines and shower (to avoid indoor "floods"). Also, with the latter, larger drain-fields are used instead of a mere plant being placed before an outlet.
Black water, water that has been used in a toilet, was usually not created within many of the earliest Earthships as the use of conventional toilets was discouraged. Instead, in the early days composting toilets were advocated, which use no water at all. However, with the new grey water treatment system design (as used in Nautilus and Helios) created by Michael Reynolds, flush toilets have now found a place in the Earthship and the general water system has been redesigned according to the new "6-step process".
Now, when the newly included flush-toilets are used, black water is not reused within the Earthship. Instead, black water is sent to a solar-enhanced septic tank with leach-field and planter cells (the whole being often referred to as the “incubator”). The solar-enhanced septic tank is a regular septic tank which is heated by the sun and glazed with an equator-facing window. The incubator stores the sun's heat in its concrete mass, and is insulated, to help the anaerobic process. Water from the incubator is channeled out to an exterior leach field and then to landscaping "planter cells" (spaces surrounded by concrete in which plants have been put). The cells are similar to the botanical cell used in grey water treatment and are usually placed just before and under the windows of the Earthship.
Earthships are designed to catch and use water from the local environment without bringing Earthships are designed to collect and store their own energy from a variety of sources. The majority of electrical energy is harvested from the sun and wind. Photovoltaic panels and wind turbines located on or near the Earthship generate DC energy that is then stored in several types of deep-cycle batteries. The space in which the batteries are kept is usually a special, purpose-built room placed on the roof. Additional energy, if required, can be obtained from gasoline-powered generators or by integrating with the city grid.
In an Earthship, a Power Organizing Module is used to take stored energy from batteries and invert it for AC use. The Power Organizing Module is a prefabricated system provided by Earthship Biotecture that is simply attached to a wall on the interior of the Earthship and wired in a conventional manner. It includes the necessary equipment such as circuit breakers and converters. The energy run through the Power Organizing Module can be used to run any house-hold appliance including washing machines, computers, kitchen appliances, print machines, and vacuums. Ideally, none of the electrical energy in an Earthship is used for heating or cooling.
The interior climate of an Earthship is stabilized and made comfortable by taking advantage of many phenomena. Mainly, the Earthship tries to take advantage of the properties of thermal mass and passive solar heating and cooling. Examples are large front windows with integrated shades, trombe walls and other technologies such as skylights or Steve Baer's
The load-bearing walls of an Earthship, which are made from steel-belted tires rammed with earth, serve two purposes. First, they hold up the roof, and second, they provide a dense thermal mass that will soak up heat during the day and radiate heat during the night, keeping the interior climate relatively comfortable all day.
In addition to high thermal mass, an Earthship may be earth-sheltered. The benefits of earth-sheltering are twofold because it adds to the thermal mass and, if the Earthship is buried deep enough, allows the structure to take advantage of the Earth's stable temperature.
The Earthship is designed in such a way that the sun provides heating, ventilation, and lighting. To take advantage of the sun, an Earthship is positioned so that its principal wall, which is nonstructural and made mostly of glass sheets, faces directly towards the equator. This positioning allows for optimum solar exposure.
To allow the sun to heat the mass of the Earthship, the solar-oriented wall is angled so that it is perpendicular to light from the winter sun. This allows for maximum exposure in the winter, when heat is wanted, and lesser exposure in the summer, when heat is to be avoided. Some Earthships, especially those built in colder climates, use insulated shading on the solar-orientated wall to reduce heat loss during the night (Reynolds 2000).
The Earthships usually use a natural ventilation system. It consists of cold(er) air coming in from a front ("hopper") window, especially made for this purpose and flowing out through (one of) the skylights that are placed on the Earthship. As the hot air rises, the system creates a steady airflow - of cooler air coming in, and warmer air blowing out