A double-pipe heat exchanger consists of 20 ft of 2-in. “Schedule 40”

steel pipe (see Table 10-22 in Perry’s Chemical Engineers’ Handbook, 9th edition), jacketed with 3-in. “Schedule 40” steel pipe. Hot water at the rate of 3,000 lb/h enters the inside pipe under pressure at 300 °F, and 2,230 lb/h of cold water enters the jacket at 60 °F. Calculate the temperatures of the streams leaving the heat exchanger and the total heat transfer rate for (a)

counter-current and

(b) co-current configurations. The convective heat transfer coefficients inside and outside the tubes are = 1,200 and =1,175 BTU/h ft² °F, respectively.