A process that moves horizontally on a psychrometric chart is known as?

A process that moves horizontally on a psychrometric chart represents a change in moisture content at constant dry bulb temperature, indicating that the energy added or removed from the air primarily affects its latent heat. In the case of a horizontal movement, the enthalpy of the air remains constant while the specific humidity changes, allowing for the understanding of how moisture contents change without altering the temperature.

This principle is critical in HVAC applications as it helps in understanding processes such as dehumidification or humidification, where the moisture level is manipulated while the temperature of the air stays the same. Hence, this horizontal movement accurately depicts a sensible process where the temperature is involved but does not change, and the focus is on the added or removed moisture.