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  antekL1 24.6.2011 (11:30)

  Let m = 650 kg be the mass of bottles,
  t1 = 15 C - the room temperature
  tm = 573 C - the melting point temperature
  t2 = 950 C - the final temperature
  Cs = ??? - solid glass heat capacity
  Cl = 1420 J / (kg * K) - liquid glass heat capacity
  Cf = 980 J / kg - the heat needed to melt 1 kg of glass.
  I found Cs = 729 J / (kg * K) and use this value because you forgot to write it down in your text.
  
  The total energy needed may be split into 3 parts:
  1) To heat the glass from room to melting temperature:
  Q1 = m * Cs * (tm - t1)
  2) To melt the glass:
  Q2 = m * Cf
  3) To heat the melted glass to the final temperature:
  Q3 = m * Cl * (t2 - tm)
  
  So the amount of heat Q = Q1 + Q2 + Q3
  Q = mC_s(t_m-t_1) + mC_f + mC_l(t_2 - t_m)
  Each part of the above equation is expressed in the same units, in joules (J).
  Q = 650\cdot 729\cdot(573-15) + 650\cdot 980 + 650\cdot 1420\cdot(950-573) \,\approx\, 613\cdot 10^6
  Answer: The energy needed is about 613 MJ per hour. This is over 600000 kWh, it is not a cheap process!

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