| Cooling Formulas |
| |
|
CONVERSION
|
|
1 Ton = 12000 Btu/hr
|
|
|
COOLING LOAD REQUIREMENT
|
|
Total Cooling Load (Btu/hr) = 4.5 x CFM x (H1 – H2)
|
| |
|
Where:
|
|
CFM = Airflow in Cubic Feet Per Minute
|
|
H1 = Entering Air Enthalpy (Btu/lbm dry air)
|
|
H2 = Leaving Air Enthalpy (Btu/lbm dry air)
|
| |
|
Or
|
| |
|
Total Cooling Load (Btu/hr) = Sensible Cooling Load (Btu/hr) + Latent Cooling Load (Btu/hr)
|
| |
|
Where:
|
|
Sensible Cooling Load (Btu/hr) = CFM x Density Factor x (T1 – T2)
|
|
Latent Cooling Load (Btu/hr) = CFM x 0.69143 x (G1 – G2)
|
| |
|
Where:
|
|
CFM = Airflow in Cubic Feet Per Minute
|
| Density Factor = |
|
1.08 +
| (70-Blower Temp) * .024
|
|
10
|
|
|
T1 = Entering Air Drybulb Temperature (°F)
|
|
T2 = Leaving Air Drybulb Temperature (°F)
|
|
G1 = Grains of Moisture of Entering Air = 7000 x humidity ratio (lbm moisture/lbm of dry air)
|
|
G2 = Grains of Moisture of Leaving Air = 7000 x humidity ratio (lbm moisture/lbm of dry air)
|
|
|
EFFICIENCY CALCULATION
|
|
SEER = BTU / W-hr
|
|
|
COST OF COOLING:
|
|
Cost of cooling = BTU/hr x hrs of operation x electricity cost ($/kw-hr) / (SEER x 1000)
|
|
|