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Creating nomographs for cooling towers

Does anybody know how to create nomographs or alignment charts for cooling towers and heat exchangers?

A little background to my question:

The work that I do involves lots of power station analysis on all types of plants. Due to the tools now available, such as computer aided analysis, all the old methods of work, such as being able to create nomographs, have been lost. I have a big interested learning things the old fashioned way with a pen and paper and not just trust what a computer tells you what it is. Your help is greatly appreciated. 


An expert in nomographs that I reached out to provided the following response:

There is some really good software for generating Nomograms called PyNomo.  You can generate nomograms using other means (Even with Excel, but it's not straightforward).  Suggest you have a look at . The developer of PyNomo, Lief Roschier is very helpful, and is worth contacting also.


Another expert I reached out to provided the following response which he permitted me to post on his behalf:

During my 39 year career with Baltimore Aircoil Co., I created a number of nomographs for selecting cooling towers. This allowed a customer to select for themselves the correct model for their specific conditions, namely Wet Bulb Temp, Range, Approach, and Water Flowrate. It also allowed them to play with these parameters to see how it would affect the model selection. In general, the nomograph reflected the performance of a single model, and then all other models were compared to that specific model, e.g. a model that was twice as large would do twice the flow, but might vary somewhat at other conditions. As the factory assembled cooling tower industry moved to CTI (Cooling Technology Institute) independently certified thermal performances, improved selection procedures were required, i.e. other models were not a constant factor and/or  slight variation with flow times the base model. This required that each manufacturer publish the the exact flow capability of each specific model at 44 different standard conditions that allows customers and competitors to see those ratings. There are now 81 worldwide manufacturers participating in this certification program with approximately 40,000 models certified.

Matthew McManus's picture
Matthew McManus on May 24, 2019 7:43 pm GMT

Thanks for the info! The first reply will require me learning some computer programming language so I may have to return to that in the future. As for the second reply about the CTI standard approach that makes a lot of sense as all the towers built from 1990's onwards all have performance curves for the customer to use. Thank you very much.

Matthew McManus's picture
Matthew McManus on May 26, 2019 8:57 pm GMT

I would be very interested if the person who worked at Baltimore air coil co could give me some advice on how to create Nomograms. I have some excel spreadsheets that I can use to calculate all the necessary answers but I just need help understanding how to set up the nomograph.

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