Daniel Rocha,
The melting temperature of most types of glass is around 550C and the
specific heat is 0.7J/gC. The latent heat of glass is 10kJ/mol, and on
average, it has 60g/mol, so we have 166J/g. 1.5*10^6g*530*0.7J +
166*1.5*10^6J per day, that around 880MJ/day. If the exposition work
lasted 8 hours a day, we have ~20KW."
A classic example of how someone without experience can get things so
wrong. You are confusing the softening point with the temperature
required to fine the glass - that is to say remove the smallest
bubbles. Ordinary furnaces used to operate @ ~1500C in my day but some
are now are over 1600C.
The many furnaces I'm familiar with typically used 4 -5 million BTU per
ton. Some used as much as 7 million BTU. Smaller furnaces use more.
This particular furnace was very unusual in that it operated as a cold
top electric furnace but glass was only used from it 8 hours a day. Of
course it had to keep working 24/7 or the throat would freeze and it
would lose the batch blanket - a design feature that made it different.
I don't have the actual figures for it but would be surprised if it were
less than 5 million BTU/ton. Most furnaces that size would use about 10
million BTU/ton
In passing, being familiar with measuring high temperatures was why I
wondered why they didn't use type S thermocouples. We would even use
type B in places where long life was required as the rhodium tends to
migrate to the platinum leg.
