Wet Bulb And Dry Bulb Temperature Chart

It is defined as air.

Wet bulb and dry bulb temperature chart. Read enthalpy values in psychrometric chart example. Draw the line of 25 0 c of wet bulb temperature axis line 2. The dbt and wbt of the air are measured by a special thermometer called sling thermometer. The temperature of the air measured by the ordinary thermometer is called as the dry bulb temperature of air commonly referred as dbt.

It is therefore measured by wrapping a wet wick around the bulb of a thermometer and the measured temperature corresponds to the wet bulb temperature. Calculate the enthalpy of that air. By definition wet bulb temperature is the lowest temperature a portion of air can acquire by evaporative cooling only. Wet bulb temperature can be measured by using a thermometer with the bulb wrapped in wet muslin.

When we know dry bulb temperature and wet bulb temperature. 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. Wet bulb temperature is the lowest temperature to which air can be cooled by the evaporation of water into the air at a constant pressure. Combining the dry bulb and wet bulb temperature in a psychrometric diagram or mollier chart gives the state of the humid air.

The relative humidity is approximately 50 the humidity ratio is approximately 65 grains h2o lb dry air. Enthalpy is measured by kj kg dry air. Psychrometric chart full tutorial dry bulb temperature t db. The wet bulb temperature is the adiabatic saturation temperature.

At lower humidity the wet bulb temperature is lower than dry bulb temperature because of evaporative cooling. The state of air with dry bulb temperature 75 o f and wet bulb temperature 62 5 o f can be visualized in the psychrometric chart as indicated below. 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. The adiabatic evaporation of water from the thermometer bulb and the cooling effect is indicated by a wet bulb temperature lower than the dry bulb temperature in the air.

Temperature of the ordinary air measured by the thermometer when it is covered by wet cloth or wick is called as the wet bulb temperature commonly referred to as wbt. When dry bulb temperature and wet bulb temperature are known we can determine the relative humidity absolute humidity and enthalpy. Dry bulb temperature tells the actual room temperature. Dry bulb temperature is 30 0 c and wet bulb temperature is 25 0 c.

The wet bulb temperature is always lower than the dry bulb temperature but will be identical with 100 relative humidity the air is at the saturation line.