Helpful Equations Part 1

Here are a few helpful equations that we've found helpful through the years. Future posts will build on this list, and the back of our line card will have a summary of them all.

Cooling tonnage:

TONS = ((evap gpm) x (evap ΔT)) / (24)

*assumes evap ΔT in degrees F, and 100%water

Efficiency conversion:

• KW/ton = 12 / EER

• COP = EER / 3.412

• EER = 12 / KW/ton

Psychrometrics

Qsensible = 1.085 x CFM x ΔT

*ΔT is deg F dry bulb

Qlatent = 0.68 x CFM x Δgrains/lb

*grains/lb measures Humidity Ratio or Specific Humidity

Qtotal = 4.5 x CFM x Δh

*h = enthalpy