Dear Dr Khalil

I disagree with what you went to,  and I agree with what Dr Reghavan believes. The double pipes heat exchanger has the best effectiveness at the conditions you mentioned.

Regards

I think you must mean shell-and-tube heat exchanger.

If both fluids are single phase, the best effectiveness is given by double pipe heat exchanger in counterflow. Every other type is inferior to this.

If the shell-and-tube heat exchanger is of the segmental baffle type, then for a small number of baffles, the performance is also sensitive to the inlet/outlet configuration of the two fluids. For more information on this, see the work of E. Gaddis and E.U. Schlunder.

Dear Dr Khalil

At the same heat exchanger capacity and fluid mass flow rate, I think shell-and tube is the best,

regards

Dear Dr Khalil

I disagree with what you went to,  and I agree with what Dr Reghavan believes. The double pipes heat exchanger has the best effectiveness at the conditions you mentioned.

Regards

Double pipe heat exchanger can withstand higher pressure in tube side and shell side and also temperature range is also higher in comparison with shell and tube heat exchanger. However. shell and tube heat exchanger is most versatile heat exchager. 

Double pipe heat exchanger is a concentric pipe heat exchanger and generally of counter flow type. In general hot fluid flows inside core and cold fluid in annulus. Shell and tube heat exchanger has shell and inside bundle of tubes. Generally, hot fluid flows in shell travels a long path since baffles are attached before fluid goes out. Cold fluid or fouling fluid inside tubes absorbs heat from hot fluid in shell which the tubes cross section (included angle between tubes be 30o generally used, 45o, 90o or 60o). Owing to the development of shell and tube heat exchanger, now a days in almost all the industrial plants, double pipe heat exchangers are replaced by shell and tube heat exchangers since the same heat capacity is obtained by shell and tube heat exchanger with reduce in length of double pipe heat exchanger (cost saving also). The effectiveness is improved in shell and tube heat exchanger compared to double pipe heat exchanger.