Wet Bulb Dry Bulb Humidity

At 100 relative humidity the wet bulb temperature is equal to the air temperature dry bulb temperature.

Wet bulb dry bulb humidity.

Air humidity can be estimated by measuring. It includes a dry bulb thermometer a wet bulb thermometer and a psychrometric chart a graph that plots the relationships between the dry and wet bulb temperature relative humidity and dew point at constant pressure. At lower humidity the wet bulb temperature is lower than dry bulb temperature because of evaporative cooling. The higher the difference in these temperatures the lower is the humidity.

The wet bulb temperature wbt is the temperature read by a thermometer covered in water soaked cloth wet bulb thermometer over which air is passed. Given the wet bulb temperature dry bulb temperature and ambient pressure the humidity of the air can be calculated as follows. Since evaporation takes up heat the thermometer will cool to a lower temperature than a thermometer with a dry bulb at the same time and place. By definition wet bulb temperature is the lowest temperature a portion of air can acquire by evaporative cooling only.

The difference between these two temperatures is a measure of the humidity of the air. Dry bulb temperature and. Note that continuously air flow around the thermometer is important to evaporate. Wet bulb temperature t wb can be measured with a standard thermometer with some wet clothing cotton or similar around the bulb.

The depression in wet bulb temperature allows the humidity to be calculated. The dry bulb temperature is the ambient temperature. Dry bulb temperature t db can be measured with a simple thermometer as shown above.