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)

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Note kind

CONVENTION

Policy level

STRICT

Keywords

In most literature, heat exchange is represented by 'Q', and heat exchange rates are represented by 'q' or either q or Q with dot '.' over it. However, Mathematica has an informal rule that custom variables (expressions) should not start with a capital letter, because such are reserved for Mathematica core.

The Webel Pys library uses the following variables for field names (although, in displays and tables it can use rich Mathematica markup):

qTot: Total heat exchange (energy).
qSen: Sensible heat exchange (energy), which cause a change in dry bulb temperature 'tdb'.
qLat: Latent heat due to water vaporisation (water gained by the humid air) or condensation (water lost by the humid air).

For heat rates (energy per time), qDotTot, qDotSen, and qDotLat are used.

Note that this convention is adopted:

Wikipedia: 'Heat released by a system into its surroundings is by convention a negative quantity (Q < 0); when a system absorbs heat from its surroundings, it is positive (Q > 0). '

And in the Webel Psy library and examples, systems are never considered to "contain heat":

Wikipedia: 'A thermodynamic system does not contain heat. Nevertheless, the term is also often used to refer to the thermal energy contained in a system as a component of its internal energy and that is reflected in the temperature of the system.'

Relates to

TRAIL: Air Conditioning Psychrometrics (vs CED Engineering course): Example results (only) in Mathematica and SysML using the Webel Psy package and MPsy class

Example 05: Sensible heating: 'qSen' (+ve): energy transfer TO humid air

Example 06: Sensible heating: 'qSen' per mass (+ve): energy transfer TO humid air

Example 07: Sensible cooling: 'qDotSen' (-ve): energy transfer rate FROM humid air

Example 08a: Humidification: Drying lumber with air: required volumetric air flow rate

Example 08b: Humidification: As a 2-step (3-state) process