3 replies to this topic

[DAIALOS]

Hello my Friends

 

I am taking the opportunity to find some help in this forum to validate my calculations in terms of an analysis I did for a cooling water system.

 

Basically I am looking to know the amount of cooling water needed in gpm for my system in order to remove the total heat required.

 

Basically I have a flow (Assumed to have same properties as water) of 426 gpm which I want to cool from 165 F to 90 F. Based on this the total amount to be removed is 15,976 BTU/hr. assuming a 90% H.E. Eff. (17,751 420 BTU/hr).

 

I am assuming that cooling water will be heated from 85F to 130F, so to be able to remove the heat required I would need 789 gpm of water. With a cooling tower capacity assuming 100% eff. Of 1,183 TR.

 

Below I include the vendor information of some the H.E. we are using for this purpose.

 

I just want to be sure that the amount of water flow I am estimating is close to the correct amount I would need for this system.

 

Thanks!

 

Atached i am incluing the excel file with the calculations.

Attached Files

•  Cooling System Analysis.xlsx   360.33KB   42 downloads

Edited by DAIALOS, 31 July 2014 - 10:39 PM.

[Bobby Strain]

The numbers above don't match the spreadsheet. And, shame on you for hiding rows.

Bobby

[DAIALOS]

Sir

 

The reason for me to hide those cells is because that data is not relevant for the calculations. Anyway you could unhide those cells by clicking right click and pressing unhide, just in case you didnt know.

 

Only one number didnt match the spreadsheet and it was because of a typo when wrtiting the above message.

 

If you are available to offer your experience in helping me validating those numbers, it would be a pleasure for me to offer you any clarification, if needed.

 

Thanks!

[PingPong]

You use conficting flowrates, temperatures and duties throughout your spreadsheet. Nobody understands what you are doing.

 

And what is 90 % Heat Exchange Efficiency supposed to mean?

 

 

It is very simple: if you need to cool down 426 gpm "water" from 165 to 90 F using cooling water from 85 to 130 F, then the required cooling water flow is: 426*(165 - 90)/(130 - 85) = ....... gpm.

You don't need a spreadsheet for that.