Thanks for the books :)

You should use mass and energy conservation law

mass and energy conservation law results in different parameters such as out temperature. I am looking for a general rule which can give a ratio between load and dimensions of tower

@ Mrs. Talieh Rajabloo

This question is very important, but it is not easy to answer. You should model a tower to answer this question. I suggest to use Kroger book. I saw that Vitalii Pertsevyi suggest these books. Be careful you need both volumes of this book. It is a very good book for this purpose. I used it and I repeated all calculations. Then I use them in modeling a hybrid cooling tower which is similar to HXI cooling tower.

Note: This book gives the answers, but if want to write a program for cooling tower, you have to write them in the format of system of equations and obtain answers.

Thanks Shahin Khosharay , I have used some literature released by Kroger . And, codes are ready in the format of system of equations . To get results for some determined data, I need to guess the width (or diameter) of tower. I am looking for some rules. Do you know any reference to give some initial value for width of cooling tower? Does it have any relation with cooling tower's load?

@ Mrs. Talieh Rajabloo

As far as I understand, you want a width (or diameter) which is appropriate for your operational conditions. Then based on this width (or diameter) , you want to calculate the other results. If want to do this task, you need some rules of thumb to determine this width (or diameter). For example, for designing distillation towers, we have such rules of thumb.

Yes, I have mentioned ''rules of thumb'' in the text of question. Do you have anyone? I am looking for some reference

Also, search mass transfer books for such rule of thumb. If there is not any rules of thumb, you have to use fluent or FLEX PDE to model the flow of air and water inside the tower to recognize which diameter or width is appropriate for influential mass and heat transfer inside your tower.

See also this book:

Rules of Thumb for Chemical Engineers

It mentions something about the dimensions of cooling towers. If you search such books, I think you can find your answer.