Chapter 5, Problem 5.24P

A system undergoes a power cycle while receiving 1450 kJ by heat transfer from a thermal reservoir at a the temperature of 780 K and discharging 560 kJ by heat transfer to a thermal reservoir at (a) 250 K, (b) 380 K, (c) 460 K.  For each case, determine whether the cycle operates irreversibly, operates reversibly, or is impossible.

As shown in the figure, a reversible power cycle R and an irreversible power cycle I operate between the same hot and cold thermal reservoir. Cycle I has a thermal efficiency equal to one-third of the thermal efficiency of cycle R. (b) If each cycle develops the same net work, determine which cycle (i) receives greater energy by heat transfer from the hot reservoir, (ii) discharges greater energy by heat transfer to the cold reservoir. WR R Hot reservoir m Qc=QH-WR l'c=QH-W₁ Cold reservoir W₁

A reversible power cycle operates between a reservoir at temperature T and a lower temperature reservoir at 200 K. At steady state, the cycle develops 40 kW of power while rejecting 1000 kJ/min of energy by heat transfer to the cold reservoir. Calculate T

2) A system undergoes a power cycle while receiving 1000 kJ by heat transfer from a thermal reservoir at a temperature of 500 K and discharging 600 kJ by heat transfer to a thermal reservoir at (a) 200 K, (b) 300 K, (c) 125 C. For each case, determine whether the cycle operates irreversibly, operates reversibly, or is impossible.

As shown in the figure below, two reversible cycles arranged in series each produce the same net work, Wcycle. The first cycle receives energy QH by heat transfer from a hot reservoir at TH = 1500°R and rejects energy Q by heat transfer to a reservoir at an intermediate temperature, T. The second cycle receives energy Q by heat transfer from the reservoir at temperature T and rejects energy QC by heat transfer to a reservoir at TC = 450°R. All energy transfers are positive in the directions of the arrows.   Determine:(a) the intermediate temperature T, in °R, and the thermal efficiency for each of the two power cycles.(b) the thermal efficiency of a single reversible power cycle operating between hot and cold reservoirs at 1500°R and 450°R, respectively. Also, determine the ratio of the net work developed by the single cycle to the net work developed by each of the two cycles, Wcycle.

Second-law efficiency is a measure of the performance of a device relative to its performance under reversible conditions.

As shown in the figure below, two reversible cycles arranged in series each produce the same net work, Wcycle. The first cycle receives energy QH by heat transfer from a hot reservoir at TH = 1000°R and rejects energy Q by heat transfer to a reservoir at an intermediate temperature, T. The second cycle receives energy Q by heat transfer from the reservoir at temperature T and rejects energy Qc by heat transfer to a reservoir at Tc = 500°R. All energy transfers are positive in the directions of the arrows. Determine: Hot reservoir at TH QH Reservoir at T R1 lo ali R2 Qc Cold reservoir at Te W. cycle W cycle (a) the intermediate temperature T, in °R, and the thermal efficiency for each of the two power cycles. (b) the thermal efficiency of a single reversible power cycle operating between hot and cold reservoirs at 1000°R and 500°R. respectively. Also, determine the ratio of the net work developed by the single cycle to the net work developed by each of the two cycles, Wcycle.

Find the cycle entropy production and answer if it operates irreversibly, reverisbly, or impossibly. A system executes a power cycle while receiving 1000 kJ by heat transfer at a temperature of 500 K and discharging energy by heat transfer at 300 K. Determine the cycle entropy production if the cycle thermal efficiency is 25% in kJ / K. Enter the answer without units, but with a minus sign if applicable. This cycle operates     irreversibly     reversibly     impossibly.

All reversible heat engines operating between the same two reservoirs have the same efficiency (the second Carnot principle).