First Law of Thermodynamics

The first law of thermodynamics expresses principle of conservation of energy.

1 2

Forms of energy: KE = ~mv Kinetic (motion of the system)

PE = mgz Potential (position of the system)

U = U(T) Internal (stored in matter)

System total energy (E) = sum of all forms of energy

Energy transfer mechanisms are work (W) and heat (Q), which are not properties of the system. Conventions: Work done by a system is positive.

Heat transfer to a system is positive.

Posted in Fundamentals of Heating. Ventilating, and Air-Conditioning