Question

The condenser in a power plant cools 10 kg/* water at 10 kPa, quality 90% so it comes out as saturated liquid at 10 kPa. The cooling is done by ocean-water coming in at ambient 15°C and returned to the ocean at 20°C. Find the transfer out of the water and the transfer into the ocean-water of both energy and exergy (4 terms).

Answer 1

C.V. Water line. No work but heat transfer out.

Energy Eq.: Q out = m. (h1 – h2) = 10(2345.35 – 191.81) = 21 535 kW C.V

Ocean water line. No work but heat transfer in equals water heattransfer out

Notice there is a large amount of energy exchanged but very little exergy.