Problem $3.(35$ pts$)$ In Figure $3$ a heat exchanger is shown where a process stream is heated from

temperature $T_{in}$ to $T_{\text{o}\text{u}\text{t}}$ using steam at constant temperature $T_{st}.$ Derive the energy balance equation for the

process assuming a lumped system $($i$.$e$.$ that system properties do not depend on the spatial position$).$

Figure $3$