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This diagram shows the block
EvaporationCalculationwith a supporting ConstraintBlock
Webel vs SysPhS-1.1: Annex A.5: Humidifier: It is NOT assumed that the specification example is completely realistic (but an attempt is made to indeed interpret it as realistic using dimensional analysis and quantity magnitude checks).With that disclaimer in mind, it's time for some analysis anyway. The water needs to be first heated to boiling point and transformed from boiling liquid to gas. Let's handle that 2nd part first. We're going to need some more thermo:
Wikipedia: 'The enthalpy of vaporization (symbol ∆Hvap), also known as the (latent) heat of vaporization or heat of evaporation, is the amount of energy (enthalpy) that must be added to a liquid substance to transform a quantity of that substance into a gas.'
Wikipedia: 'The enthalpy of vaporization is often quoted for the normal boiling temperature of the substance.'The value 2270 given for
evaporationHeatseems fine compared with some other references if it's in (J/g): "1mL water equals 1g" dirty trick is used:
Webel vs SysPhS-1.1: Annex A.5: Humidifier: Dimensional analysis of TemperatureIncrease and EvaporationCalculation implies the 'specificHeat' is a volumetric heat capacity, not a specific heat capacity (heat capacity per unit of mass).
Webel vs SysPhS-1.1: Annex A.5: Humidifier: Dimensional analysis of VaporPressureCalculationConstraint implies each 1 mL of water is equated with EXACTLY 1 g of produced vapor.There seems to be a genuine error in the value 1.996 used:
Webel vs SysPhS-1.1: Annex A.5: Humidifier: In EvaporationCalculation the specificHeat value 1.996 is off by a factor of about 2. It seems to have used the steam (gas) per gram value instead of the liquid water value per gram (or per mL volumetric) value.
It's interesting comparing the
environmentTemperature 20 °C with the room temperature 30 °C used under
Radiation. Presumably the water that is to be vaporised is initially at a distinct lower environment temperature.