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A proposed power cycle is to have a thermal efficiency of 40% while receiving energy by heat transfer from steam condensing from saturated vapor to saturated liquid at temperature T and discharging energy by heat transfer to a nearby lake at 70 F. Determine the lowest possible temperature T, in F, and the corresponding steam pressure, in lbf/in.

At steady state, a power cycle having a thermal efficiency of 38% generates 100 MW of electricity while discharging energy by heat transfer to cooling water at an average temperature of 70 F. The average temperature of the steam passing through the boiler is 900 F. Determine

(a) the rate at which energy is discharged to the cooling water, in Btu/h.

(b) the minimum theoretical rate at which energy could be discharged to the cooling water, in Btu/h. Compare with the actual rate and discuss.