When a mixture of air and water vapour is cooled at constant pressure upto saturation temperature of water vapour, the temperature attained is known as:

Concept:

• If unsaturated moist air is cooled at constant pressure, then the temperature at which the moisture in the air begins to condense is known as dew - point temperature (DPT) of air
  • If the dew - point temperature is close to the dry air temperature - the relative humidity is high
  • If the dew point is well below the dry air temperature - the relative humidity is low

• Dry Bulb Temperature: Actual temperature of gas or mixture of gases.
• Wet-bulb temperature: Temperature obtained by an accurate thermometer having a wick moistened with distilled water.
• Dew point temperature: Temperature at which the liquid droplets just appear when the moist air is cooled continuously.
• Sensible heating: Moisture content of air remains constant so specific humidity is constant, temperature increases as it flows over a heating coil.
• Sensible cooling: Moisture content of air remains constant so specific humidity is constant, but its temperature decreases as it flows over a cooling coil.