### Psychrometric Chart

#### Learning Outcomes

At the end of this module, you will be able to:

- explain how a psychrometric chart is constructed
- determine properties of an air and water vapor mixture from a psychrometric chart
- show air conditioning processes on a psychrometric chart and make design calculations

Psychrometric Chart is used widely as an easy to use nomogram to obtain numerical values of properties of air and water vapor mixtures. These values are useful in designing heating and cooling systems. In this module, we will first observe the salient features of a psychrometric chart. In the next video, we will identify the lines and curves on the chart and the properties they represent.

Now that you have seen how to construct a Psychrometric chart, in the next video, you will learn how to read the values of different properties from the chart. We will use illustrative examples and obtain numerical values.

In the following video, you will learn how to represent selected air conditioning processes on a psychrometric chart. The processes include heating, cooling, humidification, and adiabatic saturation. Once you draw a process on the chart, one can obtain numerical values for further calculations useful in the design of such systems.

Example 1 - A drying system involving a heater, a drier, and a dehumidifier

Example 2 - A drying system involving two heaters and two drying beds

Recap

In this module, you learned about a Psychrometric chart, how to draw it, how to read property values from the chart, and how to represent selected air conditioning processes on the chart. As you may have observed, this chart is a simple but useful tool in obtaining property data of air and water vapor mixtures.