An engineer proposes to eliminate the condenser in an ideal Rankine cycle to form an open cycle. Lake water is available at 16°C. The lake water is pumped to 5 MPa and then heated at constant pressure to 400°C. The “spent” steam is rejected back into the lake. Determine the first-law thermal efficiency of this process and compare it with that of Problem 8.8. What are some of the practical problems with this proposed cycle?
Problem 8.8
In a Rankine cycle, steam leaves the boiler at 400°C and 5 MPa. The condenser pressure is 0.01 MPa. The water entering the pump is saturated. Determine the first-law thermal efficiency and compare it to that of a Carnot cycle operating between the same temperature extremes.
