The Air We Recover

Psychrometrics is the study of moist air. Recovery decisions depend on four properties: dry-bulb temperature, wet-bulb temperature, humidity ratio, and enthalpy.

Key Properties

• Dry-bulb - what a normal thermometer reads
• Wet-bulb - tied to the moisture the air can hold
• Humidity ratio - mass of water per mass of dry air (kg/kg)
• Enthalpy - total energy per kg of dry air (sensible + latent)

Why Recovery Engineers Need It

Effectiveness for an enthalpy wheel is defined on enthalpy, not temperature. Reading the psychrometric chart shows how much moisture moves and what the supply air becomes after recovery.