Psychrometric Chart Dry Bulb Wet Bulb

Since this temperature is so commonly used assume that temperatures are dry bulb temperatures unless otherwise designated.

Psychrometric chart dry bulb wet bulb.

Such an instrument is called a wet bulb thermometer. Wet bulb temp c. When we know dry bulb temperature and wet bulb temperature. Enter dry bulb temperature plus either wet bulb temp rh or dewpoint temp.

By definition wet bulb temperature is the lowest temperature a portion of air can acquire by evaporative cooling only. 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. 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.

Three of these properties are sufficient to identify a state of the moist air. Now we are going to learn two of those axis dry bulb temperature and wet bulb temperature. 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 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.

Psychrometric chart includes so many axis which represent different parameters of air. Two independent intensive properties are required to completely specify the state of air in the psychrometric chart. Relative humidity rh. 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.

Altitude above sea level m. 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. Altitude select ip units for inputs. 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.

Dry bulb temp c. 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.