**HUMIDIFICATION**

GRreqd = (WGR/ SpV) Room air – (WGR / SpV) Supply Air

Lbreqd = (Wlb / SpV) Room air – (Wlb / SpV) Supply Air

Qsteam = (Qair x GRreqd x 60) / 7000

Qsteam = Qair x Lbreqd x 60

Where

• GRreqd = Grains of Moisture Required (Gr H2O per Cu-ft of air)

• Lbreqd = Pounds of Moisture Required (Lb H2O per Cu-ft of air)

• Qair = Air Flow Rate (CFM)

• Qsteam = Steam Flow Rate (Lb per hour)

• SpV = Specific Volume of Air (Cu-ft per lb of dry air)

• ▲Wlb = Specific Humidity (lb-H2O per lb of dry air)

• ▲WGr = Specific Humidity (Gr. H2O per lb of dry air)

**Humidifier Sensible Heat Gain**

H = (0.244 x Q x ▲T) + (L x 380)

Where

• H = Sensible Heat Gain (Btu/Hr)

• Q = Steam Flow (Lb-Steam/Hr)

• ▲T = Steam Temperature - Supply Air Temperature (°F)

• L = Length of Humidifier Manifold (ft)

A measure of the capacity of a dehumidifier is expressed in lbs per hour of moisture removal and is estimated by equation:

MRC = [Qair x (60 min/hr / Vs] x (GPPin - GPPout )) / 7000 grains/lb

Where,

• MRC = Moisture removal capacity (in Lb /hr)

• Qair = Volumetric rate of air (CFM)

• Vs = Specific volume of air (Cu-ft / lb)

• GPPin = Grains of moisture per pound of dry air in the inlet air stream

• GPPout = Grains of moisture per pound of dry air in the outlet air stream

The difference in (GPPin – GPPout) represents the grain "depression" or removal across the

dehumidifier.

Where

• H = Sensible Heat Gain (Btu/Hr)

• Q = Steam Flow (Lb-Steam/Hr)

• ▲T = Steam Temperature - Supply Air Temperature (°F)

• L = Length of Humidifier Manifold (ft)

**DEHUMIDIFIER EQUATIONS**A measure of the capacity of a dehumidifier is expressed in lbs per hour of moisture removal and is estimated by equation:

MRC = [Qair x (60 min/hr / Vs] x (GPPin - GPPout )) / 7000 grains/lb

Where,

• MRC = Moisture removal capacity (in Lb /hr)

• Qair = Volumetric rate of air (CFM)

• Vs = Specific volume of air (Cu-ft / lb)

• GPPin = Grains of moisture per pound of dry air in the inlet air stream

• GPPout = Grains of moisture per pound of dry air in the outlet air stream

The difference in (GPPin – GPPout) represents the grain "depression" or removal across the

dehumidifier.