Wet Bulb And Dry Bulb Temperature Chart

The dbt and wbt of the air are measured by a special thermometer called sling thermometer.

Wet bulb and dry bulb temperature chart.

At lower humidity the wet bulb temperature is lower than dry bulb temperature because of evaporative cooling. Dry bulb temperature tells the actual room temperature. Psychrometric chart full tutorial dry bulb temperature t db. The dry bulb temperature is the ambient temperature.

When we know dry bulb temperature and wet bulb temperature. Draw a vertical line from dry bulb temperature axis at 30 0 c line 1. Dry bulb temperature is 30 0 c and wet bulb temperature is 25 0 c. The wet bulb temperature is the adiabatic saturation 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. Draw the line of 25 0 c of wet bulb temperature axis line 2. Calculate the enthalpy of that air. Combining the dry bulb and wet bulb temperature in a psychrometric diagram or mollier chart gives the state of the humid air.

It is defined as air. 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. 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. 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.

At 100 relative humidity the wet bulb temperature is equal to the air temperature dry bulb temperature. When dry bulb temperature and wet bulb temperature are known we can determine the relative humidity absolute humidity and enthalpy. 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 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. 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. Wet bulb temperature can be measured by using a thermometer with the bulb wrapped in wet muslin. 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.

Read enthalpy values in psychrometric chart example.