A compressor is operating in a continuous, steady-state manner to produce a gas a temperature T2 and pressure P2 from one at T1 and P1. Show that for the time interval ?
Q + Ws = (H2-H1) ?M
where ?M is the mass of gas that has flowed into or out of the system in time ?t. Establish this result by (a) first writing the balance for a closed system consisting of some convenient element of mass, and then (b) by writing the balance equations for the compressor and its contents, which is an open system.