Specific Heat

on . Posted in Thermodynamics

specific heat 1Specific heat, abbreviated as c, is the amount of heat energy required to raise the temperature of one unit of mass of a substance by one degree Celsius or one Kelvin.  Each substance has its own specific heat, which depends on its molecular structure and bonding.  Substances with a high specific heat require more heat energy to raise their temperature than substances with a low specific heat.  This property is important in many areas of science and engineering, such as thermodynamics, materials science, and heat transfer.  In other words, it quantifies how much heat energy is needed to change the temperature of a given amount of a substance.  The specific heat of a substance is typically different for different materials and can depend on factors like temperature and pressure.

There are two main types of specific heat

  • Specific Heat at Constant Pressure (Cp)  -  This represents the amount of heat required to increase the temperature of a substance when the pressure is held constant.  Cp is generally greater than Cv.
  • Specific Heat at Constant Volume (Cv)  -   This represents the amount of heat required to increase the temperature of a substance when the volume is held constant.  Cv is generally smaller than Cp.

The specific heat of a substance plays a crucial role in various thermodynamic calculations and heat transfer processes.  It helps determine how materials respond to changes in temperature and how much heat energy is needed to achieve a certain temperature change.  For example, it is used in calculations involving calorimetry, which measures heat transfer in chemical reactions, and in designing systems like HVAC systems for efficient temperature control.  Different substances have different specific heat values, which can influence their suitability for specific applications.

 

Specific heat formula

\( c \;=\; Q  \;/\; m  \; \Delta T \)     (Specific Heat)

\( Q \;=\; c \; m  \; \Delta T  \)

\( m \;=\; Q  \;/\; c  \; \Delta T \)

\( \Delta T \;=\; Q  \;/\; c  \; m \)

Symbol English Metric
\( c \) = specific heat \(Btu \;/\; lbm-F\) \(kJ \;/\;kg-K\)
\(  Q \) = specific heat capacity \(Btu \;/\; lbm-F\) \(kJ \;/\; kg-K\)
\( m \) = mass \(lbm\) \(kg\)
\( \Delta T \) = temperature change \(F\) \(K\)

 

Specific heat formula

\( c \;=\; U^2 \;/\; 2 \; Ec \; \Delta T \)
Symbol English Metric
\( c \) = specific heat \(Btu \;/\; lbm-F\) \(kJ \;/\; kg-K\)
\( U \) = characteristic flow velocity \(ft \;/\; sec\) \(m \;/\; s\)
\( Ec \) = Eckert number \(dimensionless\)
\( \Delta T \) = temperature change \(F\) \(K\)

 

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Tags: Heat Specific Heat