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Salamander
Ceramic Infrared Emitters Technical Manual Page 15
En Español
Estimating Power Requirements
In a given heating system any or
all of the three modes of heat transfer (convection, conduction, radiation) can be
utilized. The intended purpose of the following examples is to focus on the infrared
heating component only of each heating system. That is, it is assumed that 100% of the
heat transfer in each example is by infrared radiation and any heat losses are considered
to be negligible.
Thermoforming:
Given: A thermoforming application requires that an 1/8" thick PVC sheet be
heated to 350 °F (177 °C) in 1 minute. Determine the power required using only
infrared radiation.
Calculations:
| Emissivity of the infrared source |
= .90 |
| Emissivity of PVC Sheet |
= .90 |
| Specific Heat of PVC |
= .30 BTU / lb. / °F |
| Density of PVC |
= 99 lbs. / ft3 |
| Temperature Required |
= 350 °F (177 °C) |
| Ambient Temperature |
= 65 °F (18 °C) |
Convert the PVC target into (lbs. / in2):
lbs./in2 = (99 lbs./ft3)(
1/1728 in3)(.125 in) = .007161 lbs./in2
The power required to heat the PVC sheet is given by:
Watt-Hour (Weight)(Specific
Heat)( T1 - T2 )
____________ = ____________________________________________
in2
3.412
(.007161)(.30)(350-65)
= _____________________________
= .179
3.412
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