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Specific Heat Capacity

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					Specific Heat Capacity


    Chu Wei Xiang (3S311)
     Kenneth Tan (3S209)
     Tan Yu Yang (3S323)
Specific Heat Capacity
• The amount of heat energy required to
  raise the temperature of a unit mass (of
  the body) by one degree, without going
  through a change in state
    Specific Heat Capacity
                               Heat or thermal
        Q                      energy absorbed
   c=                          or released (in J)
      m × ∆T
                                 Change in
                                 temperature (final
                                 temperature –
                                 initial
                                 temperature)
                                 [in K or °C]
Specific heat
capacity (in Jkg-1K-1
                        Mass of the substance
or Jkg-1 °C -1 )        (in kg)
Specific heat capacity
• Larger amount of heat energy is required
  to raise the temperature of a substance
  with high specific heat capacity than one
  with low specific heat capacity.
• The specific heat of almost any substance
  can be measured, these includes chemical
  elements, compounds, alloys, solutions etc.
Factor affecting specific heat
capacity
• Impurities:
• For alloys, small impurity concentrations
  can greatly affect the specific heat.
• Alloys may display difference in behavior
  even when small amounts of impurities are
  present on one element of the alloy.
Specific heat capacity and heat
capacity

• Temperature of an object is a measure of
  its random molecular motions.
• Temperature increases as the average
  speed of the atoms or molecules
  increases.
• Different materials have different specific
  heat capacity because different types of
  molecules and atoms need different
  amounts of energy to raise their speed.
Specific heat capacity and heat
capacity

• For the similar material, a larger object will
  have a larger heat capacity
   • More molecules that must move faster
     to increase the temperature.
   • Therefore they need more thermal
     energy to raise the temperature.
       List of specific heat capacities
                               c in cal/gm K or   Molar C
Substance        c in J/gm K
                               Btu/lb F           J/mol K

Aluminum         0.900         0.215              24.3
Bismuth          0.123         0.0294             25.7
Copper           0.386         0.0923             24.5
Brass            0.380         0.092              ...
Gold             0.126         0.0301             25.6
Lead             0.128         0.0305             26.4
Silver           0.233         0.0558             24.9
Tungsten         0.134         0.0321             24.8
Zinc             0.387         0.0925             25.2
Mercury          0.140         0.033              28.3
Alcohol(ethyl)   2.4           0.58               111
Water            4.186         1.00               75.2
Ice (-10 C)      2.05          0.49               36.9
Granite          .790          0.19               ...
Glass            .84           0.20               ...
Specific Heat Capacity and
Heat exchanger

If the fluid passing through the pipes is to be
warmed:
§ Fluid to be warmed: low SHC
§ Fluid used to warm: low SHC
§ Pipes (fluid to be warmed passes through):
    low SHC
                    References:
•   http://www.lifetime-
    reliability.com/Training/TGT001%20Heat%20exchanger%20basics.pdf
•   http://hyperphysics.phy-astr.gsu.edu/HBASE/thermo/spht.html#c2
•   http://www.economicexpert.com/a/Joule:per:kilogram:kelvin.htm
•   http://dic.academic.ru/dic.nsf/enwiki/17444
•   http://physics.suite101.com/article.cfm/specific_heat_capacity
•   http://www.absoluteastronomy.com/topics/Specific_heat_capacity
•   http://books.google.com.sg/books?id=SE-
    s6b6W3N4C&pg=PA195&lpg=PA195&dq=specific+heat+capacity+in+he
    at+exchanger&source=bl&ots=R5lnhqoqbh&sig=SW568rWgY3pLDaEpR
    Y-
    VsDInh2Y&hl=en&ei=Q7oCSvfoNsyGkQXoorzOBA&sa=X&oi=book_resu
    lt&ct=result&resnum=7

				
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posted:6/26/2014
language:English
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