Wet Bulb Dry Bulb Psychrometric Chart

The psychrometric chart gives the relative humidity for a given wet bulb and dry bulb temperature.

Wet bulb dry bulb psychrometric chart. Properties of atmospheric air such as the dry bulb temperature the wet bulb temperature the dew point temperature the specific humidity the relative humidity specific enthalpy and specific volume are discussed in relation to the psychrometric chart below. 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. Dry bulb temperature and 57 c wet bulb temperature experiences a temperature drop of 3 c as it passes through the 1 2 m wide stack of lumber. Dry bulb temperature is located on the horizontal or x axis of the psychrometric chart and lines of constant temperature are represented by vertical chart lines.

Two independent intensive properties are required to completely specify the state of air in the psychrometric chart. The temperature read directly on an ordinary thermometer. Psychrometric chart includes so many axis which represent different parameters of air. When we know dry bulb temperature and wet bulb temperature.

To use find the vertical line for the dry bulb temperature at the bottom of the chart and the slanted line for the wet bulb temperature at the curved top left edge. Since this temperature is so commonly used assume that temperatures are dry bulb temperatures unless otherwise designated. Relative humidity dewpoint temp c. Dry wet bulb temperature axis on psychrometric chart.

Example the state of air in the psychrometric chart. A process in which there is no change of dry bulb temperature. If the air is flowing. The relative humidity is approximately 50 the humidity ratio is approximately 65 grains h2o lb dry air.

Now we are going to learn two of those axis dry bulb temperature and wet bulb temperature. By definition wet bulb temperature is the lowest temperature a portion of air can acquire by evaporative cooling only. Dry bulb temp c. The wet bulb temperature is the temperature of an object that can be achieved through evaporative cooling assuming good air flow and that the ambient air temperature remains the same.

The higher its dew point temperature. When dry bulb and wet bulb temperatures of the air are known the dew point temperature can be plotted on the psychrometric chart fig. Determine the properties of the air at state point 2 and compare them with those at state point 1. Enter dry bulb temperature plus either wet bulb temp rh or dewpoint temp.

Relative humidity temperature in. Wet bulb temp c.