FST 110B
Lecture 1
Introductions
Course Objectives
Description of Lecture Outline
Heat content and rate of heat transfer
Heat … A manifestation of energy.
What is energy?
Energy flows in various forms: electrical energy and mechanical work
Energy is interconvertible with mass
Enthalpy or Heat content:
Heat energy stored in an object.
Internal energy—a result of the activity of atoms
Heat (or Enthalpy) = mass
specific heat
temperature difference from reference
Heat content of an object
Where Q = enthalpy, kJ
m = mass, kg
cp = specific heat
T = temperature difference,C
Rate of change of heat content
e.g. in case of a liquid flowing in a pipe, due to heat transfer, its temperature changes from inlet to
exit.
Where
q = rate of change of heat content, kJ/s
m
= rate of mass flow , kg/s
cp = specific heat, kJ/kg C
T = temperature difference from inlet to exit, C