A heat exchanger is to be constructed by forming copper tubing into a coil and placing it inside an insulated steel shell. If the following data apply, what should be the length of the coil?
(a) Water will flow inside the tubing, and a hydrocarbon vapor will condense on the outside of the tubing.
(b) ID of tubing = 0.5 in.
(c) OD of tubing = 0.6 in,
(d) Condensate rate = 1000 lb/h.
(e) Temperature of condensation = 190°F.
(f) Heat of vaporization of hydrocarbon at 190°F = 144 Btu/lb.
(g) Heat-transfer coefficient for condensing vapor = 250 Btu/(h)(ft2)(°F).
(h) Inlet water temperature = 50°F.
(i) Outlet water temperature = 90°F.
(j) Heat losses from the shell may be neglected.