Psychrometrics ties dry bulb, wet bulb, dew point, relative humidity, humidity ratio and enthalpy together, so knowing any two independent properties fixes the rest. The psychrometric chart plots them on one sheet, and engineers draw HVAC processes on it as lines: sensible heating runs straight across, cooling and dehumidifying slants down and left, and mixing two airstreams lands on a straight line between them.
Plot the coil on the psychrometric chart and you'll see it never gets the air below 55 dew point, that's why the space is clammy.
Also heard as
- psych
Related terms
Dry bulb
Plain air temperature as an ordinary thermometer reads it, kept dry and out of direct sun.
Wet bulb
The temperature a wet-wicked thermometer reads in moving air, lowered by evaporation in proportion to how dry the air is.
Dew point
The temperature at which air becomes saturated and water starts condensing out when it is cooled.
Enthalpy
The total heat content of moist air, sensible plus latent, in Btu per pound of dry air.
Humidity ratio
The weight of water vapor per weight of dry air, usually given in grains per pound.