Outside
Above Screen
Inside
Plant
Outside
Above Screen
Inside
Plant
RH Lines
Enthalpy Lines
Saturation Curve
Psychrometric Calculations & Formulas
Input Parameters
Dry Bulb Temperature (T): Air temperature measured by standard thermometer (°C)
Relative Humidity (RH): Ratio of actual to saturated vapor pressure (%)
Air Pressure (P): Atmospheric pressure (hPa)
Vapor Pressure
Saturated Vapor Pressure:
VPsat = 0.61078 × e^(17.27×T / (T+237.3))
Vapor Pressure:
VP = VPsat × (RH / 100)
Vapor Pressure Deficit:
VPD = VPsat - VP
Humidity
Absolute Humidity:
AH = (VP × 1,000,000) / (461.52 × (T + 273.15))
Unit: g/m³
Dewpoint Temperature:
Dewpoint = (237.3 × ln(VP/0.61078)) / (17.27 - ln(VP/0.61078))
Enthalpy
Total Heat Content:
h = 1.006 × T + (AH/1000) × (2501 + 1.86 × T)
Unit: kJ/kg
Where 1.006 is specific heat of dry air, 2501 is latent heat of vaporization