Dew Point Measurement and Applications
• Dew point is the temperature at which air must be cooled for water vapor to condense into dew or frost.
• It's affected by water vapor saturation pressure, which is the maximum amount air can hold.
• Air compression increases water vapor pressure, affecting dew point.
• Dew point ranges from ambient to -80°C (-112°F) in special cases.
• Compressor systems without air drying capability produce saturated compressed air at ambient temperature.
• Refrigerant dryers pass compressed air through a cooled heat exchanger, causing water to condense.
• Desiccant drying systems absorb water vapor from the air stream, producing air with a dew point of -40°C (-40°F).
• Dew point can be reliably measured by selecting an instrument with the correct measuring range and understanding the pressure characteristics of the dew point instrument.