Advantage of shell and tube heat exchanger over double pipe heat exchanger?

you.......... pls somebody answer Double pipe heat exchanger consists of two concentric pipes of different diameters.One pipe is for hot fluid and another is for cold fluid.Both may have same flow direction(COCURRENT) and opposite direction(COUNTERCURRENT). Shell and tube heat exchanger consists of a shell in which large number of parallel tubes are present.One fluid hot or cold flow in shell and other hot or cold flow in the tubes. Also in case of shell & tube(S&T) the hot fluid will have more turbulence than in double pipe heat exchanger (HE) since there are no of tubes within a shell the area for convective heat transfer is considerably increased. so these are much more preferred

Therefore the rate of heat transfer is greater in shell and tube because large surface area and enough contacting time