Chapter 7, Problem 7.29P

A system executes a power cycle while receiving 1000 Btu by heat transfer at a temperature of 900oR and discharging 600 Btu by heat transfer at a temperature of 540oR. There are no other heat transfers.Determine the cycle thermal efficiency.  Use the Clausius Inequality to determine σcycle, in Btu/oR. Determine if this cycle is internally reversible, irreversible, or impossible.

A power cycle operates between hot and cold reservoirs at 500 K and 310 K. At steady state the cycle develops a power output of 0.1 MW. Determine the minimum theoretical rate at which energy is rejected by heat transfer to the cold reservoir in MW.

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.

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.

As shown in the figure below, two reversible cycles arranged in series each produce the same net work, Weycle. 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 = 500°R. All energy transfers are positive in the directions of the arrows. Hot reservoir at T RI W. cycle Reservoir at T R2 Wcycle Cold reservoir at Te 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 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, Woycle-

A system executes a power cycle while receiving 1000 Btu by heat transfer at a temperature of 900°R and discharging 700 Btu by heat transfer at a temperature of 540°R. There are no other heat transfers. Determine the cycle thermal efficiency. Use the Clausius Inequality to determine cycle: in Btu/°R. Determine if this cycle is internally reversible, irreversible, or impossible.

The refrigerator shown in the figure below operates at steady state with a coefficient of performance (COP) of 5.0 within a kitchen at 23 °C. The refrigerator rejects 4.8 kW by heat transfer to its surroundings from metal coils located on its exterior. Determine: (a) the power input, in kW.(b) the lowest theoretical temperature inside the refrigerator, in K.

A reversible heat pump cycle operates at steady state between hot and cold reservoirs at TH = 30°C and Tc 10°C, respectively. The rate of heat transfer at the high temperature is 10 kW. a. Determine the net power input, in kW. b. Determine the heat transfer rate from the cold reservoir at Tc, in kW. c. Determine the coefficient of performance of the cycle.

Two reversible power cycles are arranged in series. The first cycle receives energy by heat transfer from a reservoir at temperature TH and rejects energy to a reservoir at an intermediate temperature T. The second cycle receives the energy rejected by the first cycle from the reservoir at temperature T and rejects energy to a reservoir at temperature TC lower than T. Derive an expression for the intermediate temperature T in terms of TH and TC when,a. The net works of the two power cycles are equalb. The thermal efficiencies of the two power cycles are equal