Closed Circuit / Hybrid Cooling Tower

https://www.brighthubengineering.com/hvac/59900-fundamentals-of-heat-exchanger-theory-and-design/

https://www.power-eng.com/articles/print/volume-121/issue-7/features/cooling-tower-heat-transfer-fundamentals.html

Yes. Perry, "The Chemical Engineer's Handbook", any edition, contains the principles, the charts and the equations.

Thank you for the replies.

The references are basically for standard cooling towers. I need designing tips for designing heat exchanger tubes placed within the cooling tower box. The water falling on the tubes is evaporatively and sensibly cooled and with water or fluid inside the tubes is only cooled sensibly.

Oho !..... Now we slowly discover what you mean as you slowly make up your mind !!!

Please provide a block diagram or PID of your proposed system for this thread to go forward..... a single sentence description is not enough.

Design tips: look to design a standard TEMA BEM style heat exchanger with forced circulation on both sides. There is no thermal advantage in placing the HX in the Cooling Tower sump

It sounds like what you envision has been incorporated into many power plants under the name "Closed Loop Cooling System".

#2⇑ still applies.

If in doubt, consult a local Process Engineer.

Closed circuit Cooling Tower

In the closed circuit, there is not contact of air with the fluid being cooled. So first there is convective heat transfer from the air to the stainless-steel/or any other materials's pipes being used to carry the fluid to be cooled out. So first of all you will calculate the convective heat transferred to these pipes

Once the connective heat transfer is obtained you will have the temperature of the pipe or cooling transferred to pipe. Using that value now you can use conduction heat transfer formulas to calculate the cooling transferred from pipe to water and the final temperature of the fluid.

for the formulas of convective and conductive heat transfer please refer to this link.

Convective heat transfer

https://www.engineeringtoolbox.com/convective-heat-transfer-d_430.html

Conductive heat transfer

https://www.engineeringtoolbox.com/conductive-heat-transfer-d_428.html