15.6 Exercise 20

A large electrical power station generates 1000 MW of electricity with an efficiency of 35.0%. (a) Calculate the heat transfer to the power station, $Q_{\text{h}}$, in one day. (b) How much heat transfer $Q_{\text{c}}$ occurs to the environment in one day? (c) If the heat transfer in the cooling towers is from $\text{35}.\text{0}º\text{ C}$ water into the local air mass, which increases in temperature from $\text{18}.\text{0}º\text{ C}$ to $\text{20}.\text{0}º\text{ C}$, what is the total increase in entropy due to this heat transfer? (d) How much energy becomes unavailable to do work because of this increase in entropy, assuming an $\text{18}.\text{0}º\text{ C}$ lowest temperature? (Part of $Q_{\text{c}}$ could be utilized to operate heat engines or for simply heating the surroundings, but it rarely is.)