Earthtubing
a non-electric, passive geothermal
solar heating & solar cooling system
Earthtubing utilizes conventional,
thin wall, plastic pipe to passive solar pre-heat your home's air intake.
Fresh air enters a system of these pipes which are laid around the exterior
and interior of your home's foundation. (Or even down the driveway!) You can
let the air draft naturally through your earthtubes for a truly sustainable,
non-electric, passive geothermal system or add fans and filters to
supplement the home's back-up heating and cooling system. Be careful with
Earthtube details, though ... while architects are warming-up to the idea,
they are making very elementary mistakes, like using large concrete (cement)
pipe that is impossible to clean.
Earth tubing (fresh air return
tempering) is not suggested for low/zero energy, sustainable applications in
humid climates where the designer is concerned about air quality.
Please note that Earthtubing is not
meant as a summer cooling system in hot, humid climates where moisture would
reach dewpoint and collect in the tubes.
The Earth is like a "solar battery" absorbing nearly half of the sun's
energy. The ground stays a relatively constant temperature throughout the
seasons, providing a warm heat source in the winter and a cool heat sink in
the summer.
Please note that earthtubing technology is not geothermal heat
pumping.
Earthtubes are sustainable,
non-electric, passive heating and cooling systems. Very simple, low-tech system without any moving parts. Passive
solar at its best.
The most important factor to
successful earthtubing is DRY EARTH.
Single HDPE Coils-we offer standard
polyethylene pipe coils in 500' lengths in 3/4", 1", 1 1/4", and 2" in SDR
11 and SDR 9. Other coil lengths are available by special order.
HDPE Geothermal Piping
System-Key Benefits
- Cost Efficient Installation- Easy to join,
lightweight, and flexible to help reduce construction and installation
costs.
- Tough and Durable- Excellent impact and abrasion
resistance. Pressure ratings based on long term testing. Exceptional
resistance to slow crack growth and environmental stress cracking.
- Ductile and Flexible- with a bending radius
equal to approximately 20 times the diameter of the pipe, HDPE piping has
the flexibility, that will make trench and downhole installation easy.
- Resistant to Chemicals and Corrosion- Excellent
resistance to most chemical compounds and aggressive soils.
- Thermally Conductive- HDPE pipe offers high
strength resin pipe material to minimize pipe wall thickness and maximize
heat transfer.
- Leak-Tight Joining- Long continuous coils or
straight lengths reduce joining requirements. Properly made heat fusion
joints are as strong as the pipe itself and do not break.
- Superior Flow Characteristics- HDPE pipe offers
high volume flows with low flow resistance. The hydraulically smooth,
non-wetting surface provides excellent flow properties. A Hazen-Williams
C-Factor of 150-155 is typically used to estimate flow resistance. HDPE
pipe does not rust, rot, corrode, tuberculate, or support biological
growth.
- Sequential Footage Markings- Coils contain
footage marker indications every 2' to assist with proper depth setting in
borehole installations.
# With any earth tube system, it is
key to note: the earthtubes enter wherever and drop down to bottom of
footers
# after entering, they encircle the interior of the frostwalls
# a small amount of slope in the earthtubes is not vital, but nice
# drill 1/8th inch "weep" holes in corners to drain condensation
# use 45's in the corners and not 90's to allow easier cleaning
# separate pipes by 4 inch minimum to ensure maximum energy transfer
# use thin wall SCH2729 four inch diameter sewer pipe (thinner than SDR35)
# drag several nylon cords through AFTER the glue sets with a wire fish
# cover inlets and outlets ALL THE TIME during installation to keep clean
# protect inlet and outlet grates from water/dust intrusion with furnace
filters
Just lay down in circles, or along the driveway, just keep in mind to
keep separated by 4 inches. And lay them deep enough in the ground as to be
below freeze line.
For a good read:
Full Description of EARTHTUBING
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