Chapter 5, Problem 5.39CU

pls answer all the given thanks

An open feedwater heater is a direct-contact heat exchanger used in vapor power plants. Shown in the figure below are feedwater heater with H20 operating data for an open 31 °C as the working fluid operating at steady state, where T1 P2=3 bar = 0.92 +2 P3 3 bar Saturated liquid m380 kg/s T, PT=3 bar Open feedwater 3 heater Ignoring stray heat transfer from the outside of the heat exchanger to its surroundings and kinetic and potential energy effects, determine the rate of entropy production, in kW/K.

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 = 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 Tand rejects energy Qc by heat transfer to a reservoir at Tc = 450°R. All energy transfers are positive in the directions of the arrows. Hot reservoir at TH R1 W cycle Reservoir at T W cycle R2 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 1000°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

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, 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 closed system undergoes a thermodynamic cycle with 2 steps: process 1-2 (from state 1 to state 2), process 2-1 (from state 2 to state 1). During process 1-2, the system received energy by heat transfer of 25J. During process 2-1, energy was transferred from the system to its surrounding by heat transfer of 15J. This is a power cycle. True or false?

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 system undergoes a refrigeration cycle while receiving Qc by heat transfer at temperature Tc and discharging energy Qu by heat transfer at a higher temperature TH. There are no other heat transfers. (a) Using energy and exergy balances, show that the net work input to the cycle cannot be zero. (b) Show that the coefficient of performance of the cycle can be expressed as: Tc TH – TeA'¯ T(Qn – Q). B = where E, is the exergy destruction and To is the temperature of the exergy reference environment. (c) Using the result of part (b), obtain an expression for the maximum theoretical value for the coefficient of performance.

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.