A psychrometric chart, often available in PDF format, graphically represents the thermodynamic properties of moist air. It correlates dry-bulb temperature (the temperature measured by a standard thermometer), wet-bulb temperature (the temperature a parcel of air would have if cooled to saturation by evaporating water into it), and relative humidity (the amount of moisture in the air expressed as a percentage of the maximum amount the air could hold at that temperature). The PDF version offers portability and ease of access for calculations and analyses. An example of its use would be determining the relative humidity of air given its dry-bulb and wet-bulb temperatures, or conversely, finding the dew point temperature.
The utilization of this type of chart is crucial in various fields due to its ability to simplify complex psychrometric calculations. It is a valuable tool in air conditioning, meteorology, agriculture, and industrial processes where controlling humidity and temperature is essential. Historically, these charts were developed to aid in the design of ventilation and air-conditioning systems, enabling engineers to optimize performance and efficiency. The readily available PDF format allows for convenient use in the field or in situations where specialized software might not be available.
