Paving stones driveway with snow melt system
Created Dec 30 2006 by W., M.
To save on the energy and
installation cost, only half of the driveway will be heated. Insulation
will help to retain the heat. The moist ground below could needlessly
take a lot of heat away from the surface where it will be
needed.
Four 462 ft. long Elektra VCD25/3550 cables. Each cable is
3550Watts @ 240V, 15.5 Amps good for near 125 sq.ft. of the coverage when
installed as 28 Watts per sq. ft.
At NJ electric energy prices of 12¢ per kWh if
the whole contraption is ON for as much as 10-12 hours a day it will
cost under $20 to use.
The ground moisture
and temperature sensor is installed for full automation and energy
savings.
-
When it is
cold and dry, nothing
happens.
-
When it is
wet and not cold, nothing
happens.
-
When it is
cold and wet, the system will turn itself
ON and stay ON until the surface of the sensor is dry.
IT IS ALWAYS ON STANDBY UNTIL NEEDED!
Each cable with its own contactor and breaker.
Ready for the winter weather?
Six months later...
To save on energy and installation cost only half of the
driveway is heated.
Sometime later...
The next day:
Notes on snow and ice melting mats or
cables:
Electrical heating mats and cables for snow and ice melting may
only be used for outdoor application. Regular indoor radiant heating cables are
not suitable for outside use and vice-versa.
Unlike anti-freeze based hydronic systems electrical snow
melting systems are fairly easy to install and maintain, and are therefore much
more practical. In addition, it is much cheaper and more reliable than hydronic
systems with pumps, mixing valves, heat exchangers, and many other components.
The primary difference is in the concept: heating with electricity produces
heat energy appropriately and exactly where it is needed, instead of heating the
liquid in one place and then delivering it somewhere else by way of pumps,
pipes, tubes and valves. For maximum efficiency, it is important to preheat the
system at the first indication of precipitation. For example, when a foot of
snow is already on the ground, trying to initiate heat will most often not work
too well.
Just like any other snow or ice melting system,
thermal insulating from the ground is critical. Moist ground will absorb
an infinite amount of heating energy produced by any system, regardless of its
power. Insulation is the cheapest and the most important component!
Amplitude of seasonal soil temperature change as a function
of depth below ground surface. Top layer of the ground is the most
effected!
Seasonal soil temperature change shown as a function of
depth below ground surface for an average moist soil.
Snowmelting heating cables or mats need to be either self
regulating or controlled by a suitable thermostat, preferably with all automatic
modes and outfitted with moisture and ground temperature sensor or even few
sensors.
A ground sensor is to be located in a shady spot and heated.
Self regulating cables which do not need thermostats are
usually quite expensive, rendering larger applications is not practical because
of the cost.
Regular snow melting cables or mats are fairly inexpensive but
need to be installed with proper spacing, allowing the system to generate at
least 25 Watts/sq.ft. or 85 BTU's per sq.ft. For driveways or walkways thicker
than 5 inches a system capable of generating 28-30 Watts/sq.ft. is needed. This
requirement is the primary system size limitation. For example a 1000 sq. ft. of
driveway at 28 Watts/sq.ft. and powered with 240 Volts will need 120 Amps of
stand-by power! Heating solely walkways, steps, or just 2-4 ft. wide tire tracks
at residential locations is much more practical than heating entire
driveways. Commercial locations usually offer much more in terms of available
power and benefits.
Please also see Toyota Motors Plant
Driveways
Please remember: Electricity can be deadly and
wiring done incorrectly can kill and start deadly and destructive fires even
when "just replacing one small
receptacle".
YOU
ARE DEALING WITH LINE VOLTAGE, not low voltage!
NEVER
EVER attempt to work or even touch the inside of the electrical components
without being 100% sure that the power is
disconnected!
If
you are not an electrcian and if you have the slightest doubt about your wiring
ability, please contact a licensed electrician and/or repairman before
doing any diagnosis, repairs or installations. The products shown here
are deemed SAFE and sound by various testing authorities but the wiring
process can only be SAFE when done with safety precautions. Please
read manuals and/or ask pros when not sure. Most of the simple
installations shown here can be done by yourself or you can have someone
qualified do it for you and THEN have the electrician check it and connect it to
power.
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