SysML4Mathematica: Example 11 [A] Total (qDotTot), sensible (qDotSen), and latent cooling (qDotLat) required for cooling air: Using CoolProp wrappers and SysML Parametric Diagrams

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Tutorial
TRAIL: Air Conditioning Psychrometrics (vs CED Engineering course): Example results (only) in Mathematica and SysML using the Webel Psy package and MPsy class
Section
Topic level
INTERMEDIATE
UML keywords
Activity
SysML keywords
constraint parameter
MD:ConstraintParameter
SysML Parametric Diagram
SysML Activity Diagram
Keywords
Slide kind
SysML Parametric Diagram
Example problem from:
CED Engineering course PDF: 'Air Conditioning Psychrometrics (A.Bhatia)'
Example question:
Determine the total, sensible and latent cooling required cooling 20,000 cfm of air from a temperature of 90 F and a relative humidity of 60% to a temperature of 55 F and 100% relative humidity.
Results (only) at:
Example 11: Total (qDotTot), sensible (qDotSen), and latent cooling (qDotLat) required for cooling air
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At the top we see a SysML Parametric Diagram representing an entry point to networks of equations for the psychrometric properties obtained from low-level CoolProp wrappers for Mathematica and the accurate calculation of the total heat exchange rate 'qDotTot', and approximate methods for calculation of the latent heat rate 'qDotLatApprox' due to water condensation and the sensible heat rate 'qDotSenApprox' for the cooling of a humid air mixture.

The other SysML Parametric Diagrams show the specific calculations, and their usages of functions from the Webel Psy library for Mathematica.

Note that:

Psychrometrics: Calculations of the mass flow rate of the dry air component (assumed constant under steady state) from the ENTRY volumetric flow rate of the humid air mixture MUST use the INITIAL state variables!
Psychrometrics: The volumetric flow rate of a humid air mixture MAY change between a State1 and State2 (but the mass flow rate of dry air does not under steady state)! This is sometimes "glossed over" in some online calculators and less formal guides.

In the next slide we see the same calculations modelled via Webel MPsy objects using SysML Activity Diagrams.

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SysML4Mathematica: Example 11 [B]: Total (qDotTot), sensible (qDotSen), and latent cooling (qDotLat) required for cooling air: Using Webel MPsy objects and SysML Activity Diagrams
Notes
[MODELLING, NAMING, TIP]{RECOMMENDED} SysML Parametrics: You can use custom stereotypes keywords «i» and «o» on constraint parameters to indicate their intended use (causality) as (i)nputs and (o)utputs on ConstraintBlocks
[CONVENTION]{STRICT} Webel: Psy/MPsy: Psychrometrics for Mathematica: Convention: 'Q' indicates the energy GAINED BY the system as heat energy transfer; 'W' indicates the work DONE BY the system on its external surroundings.
[CONVENTION]{STRICT} Webel: Psy/MPsy: Psychrometrics for Mathematica: Transferred heat (energy "Q") has field names with lower case 'qTot', 'qSen', 'qLat'. Heat rates (energy per time) have field names 'qDotTot', 'qDotSen', 'qDotLat' (to avoid clashes with Mathematica core)
[CONVENTION, NAMING, PATTERN, STYLE, TIP]{RECOMMENDED} Webel: Mathematica: TIP: Maintain a Package library of Quantity variables for frequently used units using a naming convention unit$[unitSymbol] and unit[DescriptiveName] or unit[Acronym]
[CONVENTION]{STRICT} Webel: Psy/MPsy: Psychrometrics for Mathematica: For Imperial Units (IP), International British Thermal Units (Btu) are assumed
[CONVENTION]{STRICT} Webel: Psy/MPsy: Psychrometrics for Mathematica: Relative humidity is indicated by a lower case 'r' and measured as a Real fraction (rather than as a Percentage). [Some tables and plots do SHOW the relative humidity as a Percentage.]
[CONVENTION]{STRICT} Webel: Psy/MPsy: Psychrometrics for Mathematica: Due to Mathematica's units-aware Quantity algebra system it is irrelevant what units are used for the input Quantities for creation of the MPsy objects, as long as they are dimensionally consistent!
[CONVENTION]{INFORMATIVE} Webel: Psy/MPsy: Psychrometrics for Mathematica: Most CoolProp wrappers can be invoked with the dry bulb temperature 'tdb', the pressure 'p', and one (only) of the relative humidity 'r', the humidity ratio 'w', or the wet bulb temperature 'twb'
[CONVENTION, MODELLING, NAMING]{RECOMMENDED} Webel: SysML4Mathematica: An '@' prefix in the name of a ConstraintBlock, Activity, or OpaqueBehavior indicates that it is not represented by a dedicated function in a Mathematica code library (typically for minor maths or logic)
[CONVENTION, MODELLING, NAMING]{RECOMMENDED} Webel: SysML4Mathematica: When modelling the logic flow of Mathematica code with Activity diagrams it is not necessary to model every single Mathematica construct. Placeholder OpaqueBehaviors (used via CallBehaviorActions) and OpaqueActions may be used.
[MODELLING, TIP]{RECOMMENDED} TIP: Webel: SysML/UML: On the boundary of symbols for ConstraintParameters on a ConstraintProperty (ConstraintBlock usage) symbol in Parametric Diagrams use any placement or "ordering" of ConstraintParameter symbols that works for the diagram!
[CAPABILITY, FEATURE, TOOL] MagicDraw/Cameo: Supports embedding of one or more Diagrams in another via the Diagram Overview feature. Awesome!
[MODELLING, TIP]{RECOMMENDED} Webel: SysML4Mathematica: TIP: Representing Mathematica functions as SysML ConstraintBlocks modelled in SysML Parametric Diagrams and as Activities in SysML Activity Diagrams is super for analysing the dependencies between functions and their arguments!
[ASSERTION, TIP]{STRICT} Psychrometrics: Calculations of the mass flow rate of the dry air component (assumed constant under steady state) from the ENTRY volumetric flow rate of the humid air mixture MUST use the INITIAL state variables!
[CONVENTION, LIMITATION, MODELLING, NAMING, TOOL]{RECOMMENDED} Webel: Psy/MPsy: Psychrometrics for Mathematica: '$HC' in a function name indicates pure sensible heating or cooling (with no change in water vapour content). Such functions may also be used in the pure sensible portion of a 2-step treatment.
Snippets (quotes/extracts)
 Determine the total, sensible and latent cooling required cooling 20,000 cfm of air from a temperature of 90 F and a relative humidity of 60% to a temperature of 55 F and 100% relative humidity.
Visit also
CED Engineering course PDF: 'Air Conditioning Psychrometrics (A.Bhatia)'
Visit also (backlinks)
Related slides (includes other tutorials)
Example 11: Total (qDotTot), sensible (qDotSen), and latent cooling (qDotLat) required for cooling air
Related slides (backlinks, includes other tutorials)