DESIGNEX

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Frequently Asked Questions

1.  Will I need any additional files to use DesignEx?
            If you do not have MS Access on you computer, you will need to get the MS Access runtime files from the internet in order to use the fluid database.  Everything else in included with the setup file.

2.  Is DesignEx the ultimate Heat Exchanger Design Program?
           Well, although I'd like to say yes, the answer is no.  If fact the answer is that the program that you're looking for probably doesn't exist.  The closest thing would be the program distributed by HTRI (Heat Transfer Research Institute).  Here's the difference between the two.  HTRI costs thousands of dollars and engineers somtimes find that it's not accurate for two-phase type of designs.  DesignEx is very inexpensive and the correlations used to calculate single phase heat transfer correlations are much better defined than those for two phase designs.  DesignEx is a good tool for single phase designs, and can be useful for two phase designs if the vapors are pure or are nearly pure and non-condensable gases are not present.

3.  If I purchase DesignEx, will have to purchase upgrades in the future?
            As a registered owner, you will be entitled to all future upgrades of DesignEx at no cost.

4.  What kind of technical support is available?
            Currently, I'm only one person.  I'll answer as many questions as I possibly can regarding DesignEx.  I plan to post nearly everything concerning the program here on the website to facilitate it's use in the future.

5.  What if I have a great addition that I'd like to see added to DesignEx in a future update?
            Then you should email me with the link at the bottom of the page and tell me.  I'll consider all suggestions just as I always have.  If you idea is feasible and within the scope of DesignEx, I'll be happy to implement it. 

6.  Can I design a heat exchanger with temperature crosses in DesignEx?
           While shell and tube heat exchangers can cross temperatures slightly, I've decided to have DesignEx force these designs to be done via a zoned analysis method.  Otherwise, you could receive results that are grossly underestimated.  The industrial rule of thumb is that for every NTU, you'll need one shell of a shell and tube exchanger.  If you need to design with crossing temperatures, you'll have to break the design up into two or more exchangers which is mostly likely an accurate depiction of what you'll have in real life.  This way, DesignEx can more accurately predict the area that you'll need.  Be sure to pay special attention to the LMTD correction factors for these cases.

7.  On the summary screen, DesignEx seems to be reporting the LMTD as 32 degrees higher than it should be.  Will this cause a serious problem?
           No, it's just a minor bug. When using the English unit, DesignEx is reporting the LTMD to be 32 degrees higher than it actually is on the Results form.  It's still using the correct value for the calculations.  Please make a note of this.

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

• General Information about DesignEx

• Technical Information about DesignEx

• Tips for using DesignEx