Solar Heating and Cooling
three foot thick massive tire walls and the method of incorporating
them into the earth create living spaces that retain a constant
with solar gain and natural ventilation systems built in, this
building will heat itself in the winter and cool itself in the
summer without the use of centralized fossil or nuclear fuels.
living spaces of these homes are wrapped on three sides with rammed
earth mass walls. This mass acts like a battery, storing radiant
heat and direct solar gain within it, releasing this heat as the
building cools at night and as the temperatures drop during the
winter. In addition, wrapping the east, north and west sides of
the buildings in earth berms enables the interiors of the buildings
to tap into the stable temperature of the earth's surface, the
end result being a daily and seasonal temperature far more stable
than conventional housing with average low winter interior temperatures
around 60° F (15.6° C). By adding thermal shades which
are closed in the evening on the glazed south face, more warmth
can be retained.
vent windows located on the front face and operable skylights
at the back of the room are opened allowing natural ventilation.
To increase ventilation, the number of vent windows can be increased,
and the height of the skylight box can be raised to create a
stronger draw. This natural ventilation system ensures that
indoor air is healthy.
is an important factor in the performance of these thermal mass
buildings. The roof has batt and urethane insulation with an
insulative value of R 70. Skylights are triple dome and the
glazing is double paned 1 insulated. External doors are
of insulated sandwich construction fitted in draft-tight frames.
buildings produce their own electricity with a prepackaged photovoltaic
power system. This power unit is a pre-designed, pre-built "components"called
the Power Organizing Module (POM). It can be installed and hooked
up to by any electrician. Pre-designing reduces the need for
specialists, therefore lowering the cost. The basic POM unit
works with 120 Watt solar panels which can be pole mounted or
attached to the front of building. The 8 volt - 6 B/220 Amp.
2.5 K or 4K inverter can be expanded to 8 or more 120W panels
and 16-20 batteries. The Earthship power system can be expanded
to accommodate larger families and can be supplemented with
wind turbines where applicable.
in Energy Usage
rammed earth, passive solar structure has "designed down"mechanical
systems, enabling its residents to live off of a relatively
small solar power system. The idea is to incorporate the most
efficient and low energy use equipment and appliances reducing
the overall electrical needs. There are no electrical heating
demands because of the passive solar design. The glazed south
sides of the building admit daylight, eliminating the need to
use electrical lighting in the daytime.
built-in lighting is 24V DC using super-efficient light bulbs.
The pumps for the water system are 24V DC, and the most power
consumptive appliance, the refrigerator, is a super insulated
24V upright or chest type fridge. The oven is gas because an electric
oven is a burden to a photovoltaic system. With the power inverter,
most other conventional appliances and tools can be used on this
buildings collect their own water from a unique metal roof,
silt catch and cistern system and treat their own sewage through
greenhouse technology that allows contained flush toilets. Like
the "designed down"power system, the water system
in this building reduces the overall water requirements of its
inhabitants. Data and calculations that determine how much water
a conventional home uses should not be used in determining how
much water the occupants will need because this building will
use each gallon of water four times.
water systems elicit low water consumption and go hand-in-hand
with gray water and black water treatment systems that cleanse
and reuse water.
Water Catchment and Storage
building is designed with a coated metal roof and gutter system
that transports rain and snow melt to the ends of the building
passing through a funnel which filters large debris and directs
the water into two cisterns. These cisterns have the capacity
to store 5,000 gallons of water each (more cistern storage may
be added as necessary). The cisterns are buried in the earth
barmy maintaining stable temperature and away from sunlight
therefore reducing the growth of algae.
caught on the roof and stored in the cistern flows with gravity
pressure to the water organizing module (WOM). The WOM is pre-designed
component consisting of four filters (one for drinking water),
a 24V pump and pressure gauge. As the water passes through this
unit it is filtered and pumped to a pressure tank for household
use. From there it is distributed as cold water to the kitchen
Gray Water Treatment
gray water treatment planter is a lined, contained indoor planter
that receives the once-used water from sinks, tubs and washing
machines. This water passes through a grease and particle filter
to remove large debris so as not to clog up the treatment system.
After this filter, the water is taken through a long pathway
of pit run pumice to create natural cleaning similar to a mountain
stream running and tumbling through rocks and gravel. Also,
a certain type of bacteria actually houses itself in the "caverns"of
the pumice. This bacteria attacks the bacteria in the gray water.
This pathway of pumice is placed in the bottom of a planter
designed to hold water.
planter is designed with baffles to create the longest possible
travel distance through the pumice. Above the pumice, the planter
is filled with sand and topsoil to accommodate the plants. The
plant roots bring oxygen down into the water. This combination
of travel through pumice and oxygenation by plant roots cleanses
the water to the point where it looks and smells clean. It is
not clean enough to drink, but it is clean enough to be used
for growing plants both inside and out, as well as to flush
function of these containment and treatment planters is that
the plant roots will suck up a large part of the water. This
is called transpiration. The planter is designed to allow maximum
travel of the water, and at the same time provide enough plants
to absorb most of the water. The more "jungle", the
more water will be absorbed by the plants. Twenty square feet
of planter per plumbing fixture is recommended as a minimum
water is used twice in a planter creating indoor vegetation
and making it possible to grow foods year round.
Water Flush Toilet
the end of the planter, the treated gray water is stored and
ready to be used to flush the toilet, eliminating the need to
use fresh drinking water to flush the toilet. The toilet is
the third use of the water. After the toilet is flushed, this
"black water" sewage is sent out to the outdoor contained
black water treatment system.
Water Contained Treatment System
flush toilet systems consume vast amounts of precious fresh
water, mix it with human waste and end up putting a large quantity
of it back into the earth where it can contaminate future freshwater
supplies. By separating gray water from black water, Earthships
substantially reduce the volume of water that would end up in
public sewage or a septic tank. By using treated gray water
to flush the toilet, the overall water need is again reduced.
To take this one step further, the contained black water treatment
system cleans and uses the waste water so that no waste water
leaves the site.
black water leaves the building and passes through the solar
septic tank which accelerates the anaerobic process by heating
the waste with solar energy. The solids break down and are later
washed through with the liquid waste. The liquid waste then
enters the fully lined bed and travels through layers of gravel,
pumice, soil and roots where it is absorbed by plants and cleaned.
books about Earthships by Michael E. Reynolds: