Solar Collectors and Concentrators

Modeling Solar Concentrating Systems in Thermal Desktop

Parabolic trough solar field

C&R Thermal Desktop®, CRTech TD Direct®, RadCAD®, and SINDA/FLUINT offers best-in-class thermal radiation solutions, which are critically important to both space vehicle and solar power system analyses. This tool suite also uniquely offers single- and two-phase thermohydraulics, which means an entire solar thermal energy system can be modeled from the collectors to the steam power cycle or feedwater heat exchangers.

The latter strategy was recently implemented near Grand Junction, Colorado by Xcel Energy. In that system, a parabolic trough system is used to preheat feedwater to a coal burning power plant, thereby reducing the amount of coal required.

Paraboloids and Parabolic Troughs

Many solar concentrators are paraboloids, offset paraboloids, or parabolic troughs, as pictured below. These shapes are included in Thermal Desktop as parametric objects. Parametric objects are predefined shapes that can be easily changed by changing a few values. More importantly, parametric shapes have the correct shape regardless of discretization. This fits the idea of thermal-centric: discretize for the solution and not for the shape.

Solar collector receivier temperature

Arbitrary shapes with curved elements

Parametric shapes work well for some systems, but a reflector's shape may be not be well represented by the predefined shapes. An example is a compound parabolic concentrator (CPC), or Winston cone. A CPC is an axisymmetric body formed by rotating a parabolic section about an axis such that any light that enters within the designed acceptance angle is captured at the base of the body. Curved mesh elements can be generated by TD Direct to accurately represent just about any shape of reflector with fewer nodes than possible with flat finite elements.

Example of Compound Parabolic Concentrator  

Behavior of Compound Parabolic ConcentratorRay Trace for Winston Cone

 

Additional Thermal Desktop, RadCAD, and FloCAD Capabilities for Concentrating Solar Power Systems

  • Accurate curved surfaces for radiation calculations
  • Transparent surfaces and solids with refraction
  • Mapping of thermal results to structural models
    • Receiver pipe
    • HCE supports
  • Parameterized analyses
    • External convection to ambient
    • Internal convection between receiver pipe and glass envelope
    • Optical properties of the reflector and receiver
  • Free molecular heat transfer for near-vacuum in glass envelope
  • Diffuse solar load and diffuse sky IR radiation
  • Solar tracking for surfaces or groups of objects
  • Psychrometrics for condensing air heat exchangers
  • Condenser, evaporator, and boiler sizing and simulation
  • Phase change materials for thermal energy storage
  • Turbomachine components
    • Cycle-level analysis of power generation cycles
    • Performance map-based descriptions of single- or multi-stage turbomachines
    • Steam turbines
    • Heat transfer fluid pumps

These capabilities may be used separately for component-level analyses or together for plant-level analyses.

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.