Using Exergetic Efficiencies Saturated water vapor at 1 bar enters a direct-...

Using Exergetic Efficiencies

Saturated water vapor at 1 bar enters a direct-contact heat exchanger operating at steady state and mixes with a stream of liquid water entering at 25^oC, 1 bar. A two-phase liquid–vapor mixture exits at 1 bar. The entering streams have equal mass flow rates. Neglecting heat transfer with the surroundings and the effects of motion and gravity, determine for the heat exchanger

(a) the rate of exergy destruction, in kJ per kg of mixture exiting.

(b) the exergetic efficiency given by Eq. 7.29.

Let T₀ = 20^oC, p₀ = 1 bar