1. Consider 100 kg of steam initially at 20 bar and 240°C as the system. Determine the change in exergy, in kJ, for each of the following processes:
(a) The system is heated at constant pressure until its volume doubles.
(b) The system expands isothermally until its volume doubles.
Let T0 5 20°C, p0 5 1 bar and ignore the effects of motion and gravity.
Applying the Exergy Balance: Closed Systems
2. Two kilograms of water in a piston-cylinder assembly, initially at 2 bar and 120°C, are heated at constant pressure with no internal irreversibilities to a final state where the water is a saturated vapor. For the water as the system, determine the work, the heat transfer, and the amounts of exergy transfer accompanying work and heat transfer, each in kJ. Let T0 5 20°C, p0 5 1 bar and ignore the effects of motion and gravity.