Psychrometric Chart Dry Bulb Wet Bulb

Psychrometric chart includes so many axis which represent different parameters of air.

Psychrometric chart dry bulb wet bulb. Dry bulb temp c. Such an instrument is called a wet bulb thermometer. Wet bulb temp c. 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.

Enter dry bulb temperature plus either wet bulb temp rh or dewpoint temp. By combining the dry bulb and wet bulb temperature in a psychrometric chart or mollier diagram the state of the humid air. 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. Two independent intensive properties are required to completely specify the state of air in the psychrometric chart.

Relative humidity rh. Since this temperature is so commonly used assume that temperatures are dry bulb temperatures unless otherwise designated. 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. Dry wet bulb temperature axis on psychrometric chart.

When we know 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. Wet bulb temperature is measured using a thermometer that has its bulb wrapped in cloth called a sock that is kept wet with distilled water via wicking action. On the chart the wet bulb temperature lines slopes a little upward to the left and the temperature is read at the saturation line.

A psychrometric chart figure 6 4 shows the properties of moist air in terms of dry bulb temperature wet bulb temperature relative humidity humidity ratio and specific enthalpy. Three of these properties are sufficient to identify a state of the moist air. 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. A widely used device for measuring wet and dry bulb temperature is a sling psychrometer which consists of a pair of mercury bulb thermometers one with a wet sock to measure.

Relative humidity dewpoint temp c. The wet bulb temperature and the dry bulb temperature will be identical with 100 relative humidity in the air the air is at the saturation line.