Chapter 7, Problem 7.48CU

What does the exergy principle state? The exergy of an isolated system can never decreases, but always increases O The exergy of an isolated system can never increases, but always decreases O The exergy of an isolated system can either increases or decreases O None of the above

Four kilograms of a two-phase liquid-vapor mixture of water initially at 300°C and x, = 0.5 undergo the two different processes 7.33 described below. In each case, the mixture is brought from the initial state to a saturated vapor state, while the volume remains constant. For each process, determine the change in exergy of the water, the net amounts of exergy transfer by work and heat, and the amount of exergy destruction, each in kJ. Let To = 300 K, Po =1 bar, and ignore the effects of motion and gravity. Comment on the difference between the exergy destruction values. a. The process is brought about adiabatically by stirring the mixture with a paddle wheel. Answer b. The process is brought about by heat transfer from a thermal reservoir at 610 K. The temperature of the water at the location where the heat transfer occurs is 610 K Answer

Define exergy, which is the maximum useful work that could be obtained from the system at a given state in a specified environment.

A domestic water heater holds 189 L of water at 60°C, 1 atm. Determine the exergy of the hot water, in kJ. To what elevation, in m, would a 1000-kg mass have to be raised from zero elevation for its exergy to equal that of the hot water? Let T0 = 298 K, p0 = 1 atm, g = 9.81 m/s2 .

The exergy change of a system can be negative, but the exergy destruction cannot.

If heating from saturated liquid to saturated vapor would occur at 100°C (373.15 K), evaluate the exergy transfers accompanying heat transfer and work, each in kJ/kg. Ans. 484, 0.

EXPLAIN THE THE DECREASE OF EXERGY PRINCIPLE AND EXERGY DESTRUCTION.

Thermodynamics, please show all work. Step 1 and 2.

Thermodynamics, please help and show all work please.