Vapor Compression

Air Conditioning and Climate Control Design

SINDA/FLUINT and FloCADĀ® are used in automotive climate control, electronics cooling, and building HVAC design to simulate transient operation of vapor compression (VC) cycles and for the prediction of pressures, coefficients of performance, and condenser/evaporator liquid positions in a closed two-phase system with a fixed fluid charge. The programs can also be used to size components, to estimate the impact of tolerances and other variations, and to help estimate uncertainties given limited test data.

This widespread application of FloCAD to VC cycles is largely due to an increased demand for transient modeling of air conditioning systems needed to improve energy efficiency. FloCAD's unique abilities to analyze transient two-phase phenomena have been recognized as being critical to achieving accurate performance predictions. It also has tools to deal with the complexities of capillary tubes (both steady and transient) and suction line heat exchangers (SLHX).

A key advantage of using FloCAD to model VC cycle air conditioners is that it is not written specifically to address such systems: the general-purpose nature of the code can be exploited to integrate the VC cycle model with detailed models of the application (vehicle, building, electronics cabinet, etc.).

Sample Models:

Applications in this field have included:
Results of Transient Air Conditioning Prediction

  • Component modeling (compressor, evaporator, heat exchangers, heat pump, condenser, throttling devices)
  • Tracking of charge for steady state and transient simulation
  • Cabin/room psychrometrics and venting
  • System pressure prediction
  • Parametrical analysis and design optimization for sizing of compressors and heat exchangers
  • Effects of time- and direction-varying body forces
  • Regenerative interconnections such as SLHX


Recorded Videos



Advanced Pipes in FloCAD
Thursday November 14, 9-10am MT (8-9am PT, 11am-noon ET)
This webinar introduces advanced features for FloCAD pipes in addition to working with complex geometry. Complex geometry includes interior fins and surfaces for heat transfer, flow around enclosed objects, annular flow, concentric pipes, and more. FK Locators and TEEs as modeling objects will also be introduced.
Custom Heat Transfer and Pressure Drops
Tuesday November 19, 2-3pm MT (1-2pm PT, 4-5pm ET)
Do you know what the default assumptions are in FloCAD, and whether or not they apply in your situation? Do you know how far you can go past that starting point? The answer: pretty far. There are numerous mechanisms in FloCAD for adjusting factors, scaling uncertainties, and applying different or supplemental correlations. This webinar summarizes the options available to you to customize your flow models to make sure that they apply to each new situation you encounter.
Heat Exchangers: Detailed and System-level
Thursday November 21, 2-3pm MT (1-2pm PT, 4-5pm ET)
This is two webinars in one. The first explains the use and assumptions behind the FloCAD HX system-level modeling object. The second webinar describes detailed-level modeling of complex heat exchanger passages, including application of Compact Heat Exchanger (CHX) methods.
Starting in 2020, we will begin offering Introduction to Thermal Desktop and Introduction to RadCAD as either in-person training or online training, alternating between online and in-person every three months. The training uses lectures and demonstrations to introduce you to basic Thermal Desktop and RadCAD usage. Hands-on tutorials provide practice building models and interpreting results (tutorials are completed by students outside of the online class time).
The next training class will be an online format in January 2020:
  • Introduction to Thermal Desktop (and SINDA) - A three-part series on January 14, 16, and 21 from 9am to 12pm, Mountain time
  • Introduction to RadCAD - January 23 from 9am to 12pm, Mountain time
For up-to-date schedules, fees, and policies, visit our Product Training page. To register for the class above, complete our registration form and select "Online" for the Training Format.
If you are interested in product training for your company based on your schedule, please contact us to obtain a quote for training between 8-12 attendees. We can come to your facility or the lectures can be presented online. Descriptions of the available classes can be found in our course catalog.
To keep up with our training opportunities, take a look at our new Events and Training Calendar.