solution

A feedwater heater in a vapor power plant operates at steady state with liquid entering at inlet 1 with T1 40C and p1 7.0 bar. Water vapor at T2 200C and p2 7.0 bar enters at inlet 2. Saturated liquid water exits with a pressure of p3 7.0 bar. Ignoring heat transfer with the surroundings and all kinetic and potential energy effects, determine the ratio of mass flow rates m # 1

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m # 2.

Refrigerant 134a enters a heat exchanger in a refrigeration system operating at steady state as saturated vapor at 0F and exits at 20F with no change in pressure. A separate liquid stream of Refrigerant 134a passes in counterflow to the vapor stream, entering at 105F, 160 lbf/in.2 , and exiting at a lower temperature while experiencing no pressure drop. The outside of the heat exchanger is well insulated, and the streams have equal mass flow rates. Neglecting kinetic and potential energy effects, determine the exit temperature of the liquid stream, in F.