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A rock bed consists of 6000 kg granite and is at 70oC. If the process is reversible, find the final temperature and the work done in the process.
Find the specific reversible work for a steam turbine with inlet 4 MPa, 500oC and an actual exit state of 100 kPa, x = 1.0 with a 25oC ambient.
An air compressor takes air in at the state of the surroundings, 100 kPa, 300 K. Determine the minimum compressor work input.
Assume it is reversible and find the power output. How much power could be produced if it could reject energy at T0 = 298 K?
Is the exergy equation independent of the energy and entropy equations? Find the change in exergy of the control mass for each of the three cases.
Why are reversible work and availability (exergy) connected? The total exergy is based on the thermodynamic state and the kinetic and potential energies.
Flow of 0.1 kg/s hot water at 70oC is mixed with flow of 0.2 kg/s cold water at 20oC in shower fixture. What is the rate of exergy destruction for this process?
At the start of the process, what is the rate of exergy transfer by (a) electrical input, (b) from the heating element, and (c) into the water at Twater?
Find the rate of both energy and exergy (a) from the hot gases and (b) from the condenser.
A heat engine receives 1 kW heat transfer at 1000 K and gives out 400 Was work, with the rest as heat transfer. What are the fluxes of exergy in and out?
The automatic transmission in a car receives 25 kW of shaft work and gives out 23 kW to the drive shaft. Find all the exergy transfer rates.
It now heats from ambient, 25oC, to 70?C in an adiabatic process as the computer is turned on. Find the amount of irreversibility.
Two flows of air, both at 200 kPa mix in an insulated mixing chamber. Find the irreversibility in the process per kilogram of air flowing out.
A constant flow of steel parts at 2 kg/s at 20oC goes into a furnace. Find the reversible work and the irreversibility in this process.
A counter flowing heat exchanger cools air at 600 K, 400 kPa to 320 K using a supply. Find the water exit temperature and the power out of the heat engine(s).
Find the change in exergy of the disk and the energy depletion of the car's gas tank due to this process alone.
A compressor brings a hydrogen gas flow at 500 R, 1 atm up to a pressure of 10 atm. How hot is the exit flow, and what is the specific work input?
Find the final mass, the temperature T2, the final pressure P3, the heat transfer 1Q3, and the total entropy generation.
Helium gas enters a steady-flow expander at 120 lbf/in.2, 500 F and exits at 18 lbf/in.2. Calculate the power output of the expander.
Power input to the pump is 3 Btu/s. Assuming the pump process to be reversible, compute the pump exit pressure and temperature.
Compute the heat transfer to the tank and show that this process does not violate the second law.
The isentropic efficiency may be assumed to be 90%. What pressure and temperature are required in the line upstream of the nozzle?
The inlet temperature is 1800 R, and it exhausts to the atmosphere. Find the required inlet pressure and the exhaust temperature.
Air from a line at 1800 lbf/in.2, 60 F flows into a 20-ft3 rigid tank that initially contained air. What is the net entropy change for the overall process?
A nozzle involves no actual work; how should you then interpret the reversible work? Can entropy change in a control volume process that is reversible?