a set temperature for the exiting the hot water stream, , . It is possible to measure either the exiting hot water temperature Two or the incoming hot gas temperature Tgi, but not both. hot gas colder gas Fai Fq,o I q.o cold water hotter water Fwi Fwo T w.i Two ure 1: Heat exchanger. Mass flow rates are denoted with F; temperatures are denoted h T . (a) What is the manipulated variable? (b) What is the disturbance variable? (c) What is the controlled variable? (d) In a feedback control strategy, what variable would you measure, and what variable would you adjust accordingly? (e) In a feedforward control strategy, what variable would you measure, and what variable would you adjust accordingly? (f) If we wish to raise the temperature of the exiting water, should the control valve open more or close more, and why? (g) If the outside temperature also varies significantly, disturbing the process, owing to different rates of heat transfer from the heat exchanger to the surroundings, would your feedback control strategy or feedforward control strategy be better at maintaining Two at its set point