Heating and Cooling

sensible heating

process that increases air temperature with no change in absolute humidity

sensible cooling

process that decreases air temperature with no change in absolute humidity

evaporative cooling

process involving simultaneous sensible cooling and latent heating with no change in enthalpy

enthalpy

measure of total energy content of a sample of air

dry bulb temperature

sensible or ambient air temperature

wet bulb temperature

the lowest temperature attainable by evaporation of water in a set of conditions

sling psychrometer

tool used to measure wet bulb temperature

latent heat

energy absorbed or released during matter phase transition

Psychrometric chart: find dry bulb

straight down

Psychrometric chart: find wet bulb

diagonal left

Psychrometric chart: find dew point

straight left/right

Psychrometric chart: find enthalpy

diagonal left

Psychrometric chart: find relative humidty

follow curve

BTU

British Thermal Unit, amount of heat required to raise the temperature of one pound of water by one degree Fahrenheit

specific volume of air

the inverse of density; increases as temperature increases

VAV

variable air volume, controls temperature through volume of air rather than temperature of air

VRF

Variable refrigerant flow, controls temperature through volume of refrigerant