Coil Selection Calculator
Instructions:
BTUH Capacity & Leaving Air Temperature

Select US or Metric Units

Sensible Cooling:

Select the parameter for which to solve: Sensible Cooling, Volume Flow Rate, Leaving air Temperature, or Entering Air Temperature.

Enter all of the required inputs.

Click the Calculate button, and the Result will show below the table.


Total Cooling:

Select the parameter for which to solve: Total Cooling, Volume Flow Rate, Leave air Enthalpy, or Entering Air Enthalpy (note there is a Calculate Enthalpy button to take you to our Psychrometric Calculator to solve for Enthalpy).

Enter all of the required inputs.

Click the Calculate button, and the Result will show below the table.


Latent Cooling

Select the parameter for which to solve: Latent Cooling, Volume Flow Rate, Leave air Humidity Ratio, or Entering Air Humidity Ratio (note there is a Calculate Humidity Ratio button which will take you to our Psychrometric Calculator to solve for Humidity Ratio).

Enter all of the required inputs.

Click the Calculate button, and the Result will show below the table.

Area & Velocity

Select US or Metric Units

Enter the fin length and height

Enter the flow rate

Click the calculate button, and the Results will show below the table.
Water and Glycol Flow

Select US or Metric Units

Select the parameter for which to solve: Fluid Capacity, Volume Flow Rate, Entering Temperature, or Leaving Temperature.

Enter all of the required inputs.

Click the calculate button, and the Result will show below the table.
Water Velocity

Select US or Metric Units

Enter flow rate, tube diameter, and number of tubes.

Click the calculate button, and the Result will show below the table.
Methodology and Equations :
BTUH Capacity & Leaving Air Temperature
The following equations are used in this calculator:
Sensible Cooling [BTU/h] = CFM x 1.0746 x (T1 – T2)
Latent Cooling [Btu/h] = CFM x 0.69143 x (G1 – G2)
Total Cooling [Btu/h] = CFM x 4.5 (H1 – H2)
where
CFM = volume flow rate [cfm]
G1= Entering humidity ratio [grains,moisture/lb,dry air]
G2 = Leaving humidity ratio [grains,moisture/lb,dry air]
H1 = Entering enthalpy [BTU/lb, dry air]
H2 = Leaving enthalpy [BTU/lb, dry air]
T1 = Entering air temperature [oF]
T2 = Leaving air temperature [oF]
Area & Velocity
The following equations are used in this calculator:
Coil area [ft] = Fin height x Fin length / 144 in^2/ft^2
Air Velocity = CFM / FPM
where
CFM = volume flow rate of air [cfm]
FPM = velocity of air [fpm]
Water and Glycol Flow
The following equation is used in this calculator:
Fluid capacity [BTU/h] = rho x cp x (T1  T2) x [GPM] x 60 min/hr
where
rho = fluid density [lb/gallon]
cp = specific heat of fluid [Btu/lboF]
T1 = Entering fluid temperature [oF]
T2 = Leaving fluid temperature [oF]
GPM = Volume flow rate [GPM]
Water Velocity
The following equations are used in this calculator:
V = Q x C / ID^2 / No. of Tubes
where
C = English Unit Conversion Constant = 0.408498
ID = Tubing Inner Diameter [in]
Q = flow rate [GPM]
V = velocity [f/s]