Kate and Phil Smith on mon 16 mar 98
Gavin said a great deal that seems quite accurate to me.
>There is another factor in radiative transfer.
Gavin,
Great comments and discription.
I'd like to add a point or two that may be over looked too often.
Atmosphere.
The chemistry of the atmosphere plays a major role in radiant heat
transfer. In our day to day life we now see Argon and Krypton used in
insulated window glass in place of air reducing radiant energy flow.
As the interior temperature rises within the kiln the chemistry of the
atmosphere also changes. As molecular size of the chemistry making up
the atmosphere increases it begins to block radiant flow. Molecular size
begins to equal or exceed wave length size(?).
Physics and chemistry were never my strong point and it was 30+ years ago
to, so these could just be rambilngs.
Why might some one see reduced energy consumption from a coating applied
within a kiln?
Reduced air flow to the exterior through the kiln wall system.
The surface and joints of the brick work are parged with this material
that fills pores. When a kiln is operating, electric or gas, the vessel
is, for the most part, pressureized. this hot air leaks out anywhere it
can.
Brick walls are not waterproof, thats why a wythe is always place between
the exterior course and the interior wall. Air or atmosphere is a fluid.
The coating simply reduces the air leakage.
Consider: The case of a gas kiln with a fiber insulation. The flow of
combustion products over the surface of the fiber will penitrate the
fiber to a degree, reducing the effective insulation value by stripping
the embodied air or by pushing or moving it.
My point is, The atmosphere may prevent much radiant transfer of heat.
The movement within the atmosphere may play a major loss in thermal
energy from the body of the kiln.
The simple parging of surfaces reduces leakage area, reducing thermal
losses.
Viola! Energy savings, and quicker rise in temperature within the kiln.
Phil Smith
White Bear lake, MN
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