Energy Analysis of Control Volumes at Steady

Chapter 4, Problem 73P

(choose chapter or problem)

As shown in Fig. P4.73, Refrigerant 134a enters a condenser operating at steady state at \(70 \mathrm{lbf} / \mathrm{in}^2, 160^{\circ} \mathrm{F}\) and is condensed to saturated liquid at \(60 \mathrm{lbf} / \mathrm{in}{ }^2\) on the outside of tubes through which cooling water flows. In passing through the tubes, the cooling water increases in temperature by \(20^{\circ} \mathrm{F}\) and experiences no significant pressure drop. Cooling water can be modeled as incompressible with \(v=0.0161 \mathrm{ft}^3 / \mathrm{lb}\) and \(c=1 \mathrm{Btu} / \mathrm{lb} \cdot{ }^{\circ} \mathrm{R}\). The mass flow rate of the refrigerant is \(3100 \mathrm{lb} / \mathrm{h}\). Neglecting kinetic and potential energy effects and ignoring heat transfer from the outside of the condenser, determine

(a) the volumetric flow rate of the entering cooling water, in \(\mathrm{gal} / \mathrm{min}\).

(b) the rate of heat transfer, in Btu/h, to the cooling water from the condensing refrigerant.