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How do we Calculate Temperature & Time of Heating Element

  1. Nov 7, 2007 #1
    How do we Calculate Temperature & Time of Heating Element

    Heating Wire having the following Data :
    SWG 16(1.63mm)
    Specific Resistivity = 1.45 ohms-mm-3
    Density = 7.1 gm-cm-3
    Resistance = 0.685 ohms/Meter
    Weight = 15 Gram/Meter

    (a)In order to Build Heating Element using the above wire for Making 2.5 KiloWatt heating Element
    (b)In Order to Build Heating Element using the above wire for Making 3.5 KiloWatt heating Element

    Take ambient & room temperature as 35 degree Centrigrade.
    How to Calculate the following :
    (a)Formula for Calculating Temperature Raised in 1 hour ?
    or alternately What would be temperature of heating element after Heating Element heated for 1 Hour?

    (b)Formula for Calculating, How Many Calories of Heat in generated in 1 hour?
    (c)Say if the Temperature is raised till (i)800 degree Centigrade what would be the Kilowatt generated & in what time this Temperature would be raised?

    (c)Say if the Temperature is raised till (ii)1000 degree Centigrade what would be the Kilowatt generated & in what time this Temperature would be raised?

    Please state the explaination using formulas.
     
  2. jcsd
  3. Nov 7, 2007 #2

    Astronuc

    User Avatar

    Staff: Mentor

    Well energy is just power * time.

    So the energy delivered by the heating 2.5 kW heating element is just 2.5 kW*3600 s, and that delievered by the 3.5 kW element is 3.5 kW*3600 s.

    Now is one supposed to calculate the heating of the room?

    If the heat transfer is steady-state, can one use radiative heat transfer equation?
    http://hyperphysics.phy-astr.gsu.edu/hbase/thermo/stefan.html#c2

    The power radiated depends on the current and resistance of the wire = P = I2R.
     
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