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DESIGNEX

DesignEx has been discontinued

    DesignEx is the long awaited shell and tube heat exchanger program brought to you by The Chemical Engineers' Resource Page. Briefly, DesignEx was designed as a TOOL to help engineers design shell and tube heat exchangers. It requires knowledge of heat transfer and a basic understanding of how to manipulate variables to gain the desired design. DesignEx is powered by widely accepted heat transfer correlations and eight common tubesheet layout from TEMA (Tubular Exchanger Manufacturer's Association). At the very heart of the program, is an alogorithm that cycles through the possible solutions to your exchanger based on the geometric and operating data that you've entered. Once all of your constraints are met, being velocity, pressure drop limitations, and heat duty, DesignEx displays the exchanger data. However, DesignEx was not meant to be foolproof. For example, if you can't seem to get a design that meets your velocity or pressure drop constraint, you must recognize that you should increase the tube diameter that you have DesignEx design for. This is an example of how engineering judgement is necessary.
     This program was written due to the absence of an affordable tool to HELP engineers design heat exchangers. Previously, you had two options. You could design exchangers by hand while using spreadsheets to handle the calculations or you could spend thousands of dollars for a commercial simulator or design program. DesignEx fills the large gap in between the two extremes.

Bottom Line Summary of DesignEx:

"If you're looking for a program to help you design single phase shell and tube heat exchangers at a very low price, then DesignEx is for you.  If you often times have to design two phase heat exchangers and are seldom asked to design single phase heat exchangers, then DesignEx may not be for you."

     The interface for DesignEx was written with one thought in mind.....simplicity.  The main menu greets the user with buttons that corresponds to the type of system to be designed.  Simply click on the button that best describes what is happening inside your heat exchanger.

     If your system has multiple zones (see Design Consideration for Shell and Tube Exchangers), DesignEx easily gathers information about where the phase change is to occur. 

     The screens used to gather information are simple to follow, DesignEx will even help calculate your material and energy balance.  Help screens are available in case you need some advice along the way, it's doubtful that you'll need them.  DesignEx also examines the values that you enter to be sure that they "seem right".  The program checks the physical properties and other inputs against an expected range.  If your value is outside of this range, DesignEx points this out and asks you to confirm the value.  This eliminates careless mistakes in data entry.  DesignEx will also check the energy balance to be sure that the flow of heat is correct and that there are no crossing temperatures.

     Once the necessary data has been entered, the user is confronted with another easy-to-use screen for choosing a geometry configuration.   Registered users of DesignEx can chose from 8 different TEMA tubesheet layouts ranging from 5/8 in tubes to 1 1/4 in tubes on various pitches. The trial version is limited to only 5/8 in tubes on 13/16 in square pitch. This allows everyone to see how the program works before unlocking the software. The TEMA configurations available include Tema P or S (floating head), Tema L or M (fixed head), and Temu U for a U-tube bundle. Notice the fixed head exchangers are only available for sizing on triangular pitch as described by the tubesheet layouts. The tubesheet layouts included in DesignEx are from Perry's Chemical Engineers' Handbook 6th Edition.  The user can also enter a baffle spacing, tube thermal conductivity, and fouling coefficient on this form.  If you're not sure what these values may be, don't worry, DesignEx has default values you can use.

     The Results form displays a comprehensive summary of the exchanger.  Values for each individual zone are shown (if there is only one zone, the other two are turned off as shown above). The calculated and the geometric area are shown. The calculated area is the area necessary to achieve the required heat transfer while the geometric area is the area available from the current exchanger configuration. Usually, you will want these values to be as close as possible with the geometric area being slightly larger. If results are obtained like the one above, the user would simply go back and chose a shorter tube length in order to reduce the geometric area.  This is an example of how engineering judgement is necessary in order to effectively use DesignEx.  If your design is being velocity or pressure drop limited, you can simply change the allowable values on the Results form and click "Recalculate".   DesignEx will recalculate the exchanger for you right there.

     The Exchanger Summary screen will give you a breakdown of the exchanger that DesignEx has chosen for your system.

     You can also print a complete summary of your heat exchanger or lauch your default email program and email the results to a friend or coworker.

Purchase DesignEx for only $55.00 USD

     Feel free to download DesignEx and evaluate it.   If you like it and would like to keep it, simply click on the "Purchase" button and follow the directions.   You can pay with your credit card online via RegSoft.  As a registered user, you will be entitled to all subsequent updates of DesignEx.

Download DESIGNEX

     For more information on DesignEx, see one of the following:

• More Technical Information about DesignEx

• Tips on using DesignEx

• FAQ about DesignEx