Dew point temperature calculation for moist air between 0°C and 30°C with partial pressure of water vapor as an input.
The correlation used in this model is valid for dew point temperatures between 0°C and 30°C. It is an approximation to the correlation from 2005 ASHRAE Handbook, p. 6.2, which is valid in a wider range of temperatures and implemented in Buildings.Utilities.Psychrometrics.Functions.pW_TDewPoi. The approximation error of this simplified function is below 5% for a temperature of 0°C to 30°C. The benefit of this simpler function is that it can be inverted analytically, whereas the other function requires a numerical solution.
function TDewPoi_pW_amb extends Modelica.Icons.Function; input Modelica.Units.SI.Pressure p_w(displayUnit = "Pa", min = 100) "Water vapor partial pressure"; output Modelica.Units.SI.Temperature T "Dew point temperature"; end TDewPoi_pW_amb;
extends Buildings.Utilities.Psychrometrics.Functions.BaseClasses.pW_TDewPoi_amb
as this gives a compile time error in OpenModelica as the input argument T
cannot be found.
smoothOrder=99
and displayUnit
for pressure.