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.

The higher the difference in these temperatures the lower is the humidity. Relative humidity is measured using a device called a sling psychrometer this consists of 2 side by side conventional thermometers one of which the wet bulb thermometer has a wetted wick placed at the bottom the other the dry bulb thermometer has no wetted wick. The difference between these two temperatures is a measure of the humidity of the air. The depression in wet bulb temperature allows the humidity to be calculated.

By definition wet bulb temperature is the lowest temperature a portion of air can acquire by evaporative cooling only. Dry bulb temperature t db can be measured with a simple thermometer as shown above. When the psychrometer is swung around by its attached chain or handle the air causes the water on the wick to evaporate which. The dry bulb temperature is the ambient temperature.

At lower humidity the wet bulb temperature is lower than dry bulb temperature because of evaporative cooling. A wet cloth is placed over the bulb of a thermometer and then air is blown over the cloth causing the water to evaporate. 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.

Dry bulb temperature and. Air humidity can be estimated by measuring. Wet bulb temperature t wb can be measured with a standard thermometer with some wet clothing cotton or similar around the bulb.