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