A counter flow double pipe heat exchanger has hot distilled water at 80°C entering
the annulus at a flow rate of 1 kg/s. Cold distilled water at 50°C enters the inner
tube at a flow rate of 0.9 kg/s. The heat exchanger consists of 9 hairpins, each with
a length of 2 m. The outer pipe is 2-nom sch 40 commercial steel and the inner tube
is 1-std type M copper. After one year of continuous service, determine the
a. Outlet temperatures of the hot and cold-water flows
b. Heat transfer rate (kW) between the hot and cold water
c. Pressure drop through the inner tube (kPa)
d. Pressure drop through the annulus (kPa)
When computing the pressure drops, ignore the effect of diameter changes due to
fouling.