Humidity Ratio Psychrometric Chart Jun 2026

The humidity ratio, often denoted by the symbol ω (omega), represents the mass of water vapor present in a given mass of dry air. It's a direct measure of the absolute amount of moisture in the air, usually expressed in units of grams of water vapor per kilogram of dry air (g/kg). This ratio provides a clear indication of the air's moisture content, independent of its temperature.

[ W_s = 0.62198 \cdot \fracP_sat(T)P - P_sat(T) ] humidity ratio psychrometric chart

To determine latent cooling load:

On a psychrometric chart, the humidity ratio is typically represented by a series of vertical lines, each corresponding to a specific humidity ratio. These lines are parallel to the temperature axis and are usually labeled with their respective humidity ratio values. The humidity ratio lines are an essential reference for determining the absolute moisture content of air at any given point on the chart. The humidity ratio, often denoted by the symbol

This paper aims to: