Vertical Thermosiphon Heat Exchanger (VTD) is a software application that uses kern method to do the thermal design calculations for Vertical thermosyphons.

Below are the main features:

Vertical Thermosiphon Heat Exchanger Main Features

  1. The software will allow the user to enable built in tube counts tables or use own values for specifying tube dimensions and number. If use is using own dimensions; the software can also calculate the number of tubes and shell diameter.
  2. Support S.I Units and English (U.S) Units of measurement
  3. Thermal design calculations using kern method
  4. Minimum and maximum circulation ratio as well as minimum and maximum tube lengths can be specified for iterations.
  5. Liquid height for circulation check
  6. Unit Converter includes 23 measurements units with 200-unit conversions
  7. Select TEMA types/designations
  8. Heat load can be entered or calculated
  9. Counter flow or parallel flow arrangement
  10. Calculate or specify Recirculation ratio
  11. Calculate or specify exit vapor mass fraction
  12. Calculate pressure drops, overall heat transfer coefficients…etc, the table included below includes more details on calculated variables but not limited to all of them.
  13. The calculations are preformed using trial and error basis. Based on the user’s choice the software can either start with iterating the recirculation ratio or the tube length.
  14. Advisory design recommendations and validation for maximum heat flux density rate.
  15. Mist flow at tube outlet check
  16. Driving force check

Databases / Tables

  1. Water and steam properties
  2. Tube counts
  3. Fouling Factors
  4. Typical film heat transfer coefficient values, store your own values too!
  5. Material thermal conductivities
  6. Estimate the Physical properties of pure components for more than 1450 components; the database has the ability to estimate Thermal Conductivity, Density, Heat Capacity and Viscosity. The database also included critical properties, boiling and melting points and come as a standalone interface but easily integrated with the software.
  8. Ability to add your own properties in the additional user databases.


  1. Results are initially displayed in a data grid table containing all cases side by side with the initial case or main case being the first in the table.
  2. Drawing summary can be generated for individual case results
  3. The table with all cases can be copied to clipboard for pasting anywhere.
  4. A results summary report of the case selected can also be generated copied or exported to .csv as well as printed.
  5. Results can also be exported to .csv file to be opened in any office software such as Microsoft excel or open office.
DescriptionRequired inputOptional inputCalculated variableComments
Physical propertiesYes
Prandtl numberNoYesYes
Inlet mass flow rateYesYesYesCalculated for unknown side
Heat DutyNoYesYes
Log Mean TemperatureYes
Heat transfer areaYes
Flow areaYes
Mass velocityYes
Exit liquid mass flow rateYesProcess side
Exit vapor mass flow rateYesProcess side
Exit vapor mass fractionYesYesProcess side
Shell diameterYesYes
Number of tubesYesYes
Tube thicknessYesYesBWG list available
Tube clearanceYes
Tube lengthYes
Tube pitchYes
Tube inside diameterYesYes
Tube outside diameterYes
Number of bafflesYes
Baffle cutYes
Baffle to shell clearanceYesYes
Maximum allowable heat fluxYesYesAssumed value can be provided
Heat transfer coefficientYesYes
Overall heat transfer coefficient (Clean)Yes
Overall heat transfer coefficient (Design) Yes
Lockhart-Martinelli parameterYes
Critical mass flow velocity for mist flow checkYes
Pressure drop – inletYesShell side
Pressure drop – frictionalYesShell side
Pressure drop – outletYesShell side
Pressure drop – inlet YesTube side
Pressure drop – outlet YesTube side
Pressure drop – frictional YesTube side
Pressure drop – static YesTube side
Pressure drop – accelerationYesTube side
Driving forceYes
Head elevationYes
Required liquid height for circulationYes
Recirculation ratioYesYes

Screen Shots Links

Click here for Screen shots on Facebook
Click here for Screen shots on Flickr

vertical thermosiphon


Click here to download the demo version of this software. The demo will operate for 90 days with the 4 examples provided in the main screen.

Latest Demonstration Video

Example 1 English / US Units

Example 2 – SI Units


00:01:12 Water and steam properties
00:02:16 Fouling factors
00:02:46 Heat transfer coefficients
00:03:00 Material thermal conductivity
00:03:24 Units converter
00:04:09 Fluids user database for storing custom properties
00:04:40 Importing physical properties

Storing data in fluids user database