GetMoistAirDensity Function

  function GetMoistAirDensity(TDryBulb, HumRatio, Pressure) result(MoistAirDensity)
    !+ Return moist air density given humidity ratio, dry bulb temperature, and pressure.
    !+ Reference:
    !+ ASHRAE Handbook - Fundamentals (2017) ch. 1 eqn 11

    real, intent(in)  ::  TDryBulb
      !+ Dry-bulb temperature in °F [IP] or °C [SI]
    real, intent(in)  ::  HumRatio
      !+ Humidity ratio in lb_H₂O lb_Air⁻¹ [IP] or kg_H₂O kg_Air⁻¹ [SI]
    real, intent(in)  ::  Pressure
      !+ Atmospheric pressure in Psi [IP] or Pa [SI]
    real              ::  MoistAirDensity
      !+ Moist air density in lb ft⁻³ [IP] or kg m⁻³ [SI]
    real              ::  BoundedHumRatio
      !+ Humidity ratio bounded to MIN_HUM_RATIO

    if (HumRatio < 0.0) then
      error stop "Error: humidity ratio is negative"
    end if
    BoundedHumRatio = max(HumRatio, MIN_HUM_RATIO)

    MoistAirDensity = (1.0 + BoundedHumRatio) / GetMoistAirVolume(TDryBulb, BoundedHumRatio, Pressure)
  end function GetMoistAirDensity