C120-H007-05EN 51
4.4 Thermal Load and Cooling Capacities
The formula terms are:
zFlow rate: Sensible heat from the thermal load divided by the temperature
difference and the heat removed to cool a unit volume by 1°C (34°F).
zThermal load: While the thermal load is a sum of sensible heat and latent heat,
sensible heat accounts for such a large proportion of the thermal load in a computer
room that the thermal load is assumed to be equal to the sensible heat.
Thermal load = Sensible heat + Latent heat Sensible heat
• 1.0 or 0.24: Specific heat of the air [kJ/(kg ⋅ °C )] or [Btu/(lb ⋅ °F)]
• 0.84 or 1.35: Specific volume of the air (m3/kg) or (ft3/lb)
•24°C or 75.2°F: Air conditioner inlet air temperature
•11°C or 52°F: Approximate temperature of the air on the coil surface
of a room air conditioner
• 0.9: Approximate bypass factor of a room air conditioner
• 60: Conversion to minutes (min/h)
•18°C or 64.4°F: Outlet air temperature of an underfloor-ventilation air
conditioner
Flow rate Sensible heat from thermal load
Temperature difference Specific heat/Specific volume×
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