Problem 6.7:
Steam at 5 bar, 300 °C is condensed to saturated liquid in at 5 bar in a heat exchanger at a mass flow rate of 1 kg/s. Cooling is provided by water, which enters the heat exchanger at 20 °C 1 bar and exits at 60 °C. Neglecting pressure drop in pipes and heat losses to the surroundings, determine the flow rate of the cooling water, the amount of heat that is exchanged, and the rate of entropy generation.
Problem 6.8:
Steam enters a cooling tower at 200 °C and exits at 60 °C. Cooling is supplied by the surroundings which are assumed to be at 30 °C. The process takes place under atmospheric pressure (1 bar).
a) Calculate the amount of heat removed from the steam.
b) Calculate the entropy change of the steam.
c) What is the entropy generation?
d) Draw a PV graph and show the path of this process.