Chapter 5, Problem 5.35CU

Three sub steps of a thermodynamic cycle are employed in order to change the state of a gas from 1 bar, 1.5 cubic meter and internal energy of 512 kJ. The processes are: 1st step: Compression at constant PV to a pressure of 2 bar and internal energy of 690 kJ. 2nd step: A process where work transferred is zero and heat transferred is - 150 kJ. 3rd step: A process where work transferred is -50 kJ. without KE and PE changes, determine: a. heat transferred during 1st step (kJ) b. heat transferred during 3rd step (kJ)

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.

A power cycle operating between two reservoirs receives energy QH by heat transfer from a hot reservoir at TH = 2000 K and rejects energy Qc by heat transfer to a cold reservoir at Tc= 400 K. For each of the following cases determine whether the cycle operates reversibly, irreversibly, or does not verify the second law of thermodynamics (make all necessary calculation for each case). a) QH= 1200 kJ and Wcycle = 1020 kJ b) QH= 1200 kJ and Qc = 240 kJ c) Wcycle = 1020 kJ and Qc = 600 kJ d) n =40%

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

6.5

2. A power cycle receives energy QH by heat transfer from a hot reservoir at TH = 1200 R and rejects energy QC by heat transfer to a cold reservoir at TC = 400 R. For each of the following cases, determine whether the cycle operates reversibly, operates irreversibly, or is impossible. (a) QH = 900 Btu, Wcycle = 450 Btu (b) QH = 900 Btu, QC = 300 Btu (c) Wcycle = 600 Btu, QC = 400 Btu (d) Eff. = 70%

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 Te - 500°R. All energy transfers are positive in the directions of the arrows. Determine: Hot reservoir at TH lH R1 Reservoir Q at T 20 R2 lc Cold reservoir at Tc We cycle W Wcycle (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 network developed by the single cycle to the network developed by each of the two cycles, Wcycle-

A fluid at X bar of 0,733 occupying 0.09m^3 is compressed reversibly to a pressure of Y bar of 11 and a specific volume of Z=0.55m^3/kg according to the law of Pv^n=c. The fluid then expands reversibly according to the law Pv^2=c to the value A bar of 2,2.A reversible cooling at constant volume then restores the fluid back to initial state. Calculate (a) mass of the fluid present;(b) the value of n in the process ;(c) the network of the cycle and (d) Sketch the P-v diagram for the cycle.