Operation of a simple double-pipe heat exchanger. A cold-water stream, 5400 lb _m /hr at 70 ⁰ F, is to be heated by 8100 lb _m /hr of hot water at 200 ⁰ F in a simple double-pipe heat exchanger. The cold water is to flow through the inner pipe, and the hot water through the annular space between the pipes. Two 20-ft lengths of heat exchanger are available, and also all the necessary fittings. By means of a sketch, show the way in which the two double-pipe heat exchangers should be hooked up in order to get the most effective heat transfer.