Electric Thermal Storage
ETS heaters use high-density ceramic bricks to store heat
given off by elements inside the heater. The elements come on during the
co-op's off-peak times to heat up the brick. The stored heat is then released
throughout the day. Because the heaters use electricity off-peak, you receive a
discount on the electric rate for the ETS heater.
ETS is a great replacement for kerosene and fuel oil space heaters and for wood
stoves. Many members also use them to supplement their existing electric
heating system. While one unit usually won't heat your entire home when it gets
really cold, multiple units can be installed to keep you warm all winter long.
How Does ETS Work?
It's really simple. ETS cabinets are filled with bricks made of special
materials that store heat. Electric elements, similar to those found in
electric ovens, pass through the bricks. When the elements are on, or charging,
some of the heat is released into the room to provide immediate comfort. The
rest of the heat is store in the bricks until it's needed.
Space-age insulation around the core helps the bricks retain stored heat. After
the ETS unit has been charged, fans inside the heater move air around the
bricks. The air is warmed to 180 to 200 degrees and returned to the room. Since
the process is controlled by a wall thermostat, you can get as much or as
little of the heat as you want-whatever is most comfortable.
What Makes The Bricks So Special?
High-density iron oxide ceramic bricks surround the elements to absorb heat. A
high-density compound accomplishes two things. First, it holds more heat for a
longer period of time. Second, it requires less space, and that means a
slimmer, more attractive cabinet.
Although a brick measures only 7" by 8" by 1-3/4" high, it
weighs 10 pounds. Nine bricks are required for each heating element. The
heating elements also are crafted from special long-life material. That enables
the manufacturer to offer a full five-year warranty on the elements. Other
parts are warranted for three years.
At maximum charge, the core of the ETS unit reaches about 1,400 degrees. The
heat is stored in the bricks until you need it. In one test, the core
temperature was about 250 degrees three days after the unit was shut
But With Heat That Intense, Is It Safe?
Perfectly. When we say space-age insulation, we mean it. Actually, there are
two types of insulation used-both highly resistant to heat transfer. One is
aluminum silicate spun into a tightly woven blanket. The other is chemically
identical to tiles used to cover space shuttles. Their combined resistance to
heat loss has obvious benefits to making the unit more efficient, but they also
make it safer.
At maximum charge-and remember that the core temperature is about 1,400
degrees-the skin temperature of an ETS heater is about 180 degrees. That sounds
high, but compare it to wood stove. The skin temperature of a stove can be as
high as 600 degrees. Another way to compare would be to consider that if you
accidentally touched an ETS unit with your hand, it would be uncomfortable, but
you could react before any burn would occur. With a wood stove, your hand would
be burned immediately.
Still, some common sense needs to be exercised around ETS units because of the
heat generated. For example, you should allow 1 1/2" clearance on the
sides, back and between the top of the unit and any shelf. If the unit is
enclosed in a wooden cabinet, side and back clearance should be increased to
2". All fabric items, such as curtains and bed clothes, should be at least
4" from the unit at all times.