Apower cycle operates between a lake’s surface water at a temperature of 300 k and water at a depth whose temperature is 285 k. at steady state the cycle develops a power output of 10 kw, while rejecting energy by heat transfer to the lower-temperature water at the rate 14,400 kj/min. determine (a) the thermal efficiency of the power cycle and (b) the maximum thermal efficiency for any such power cycle

a) Efficiency: 4%

b) Maximum thermal efficiency: 17%

Explanation:

First we calculate the total heat that come from the hot reservoir. This heat is the work output plus the rejected energy to the cold reservoir.

The efficienccy of the cycle can be calculated as the ratio between the work output and the heat input.

The maximum thermal efficiency of this cycle can be determined in function of the temperatures of the reservoirs by this equation: