1. The Airflow Sizing Formula
To establish the required volumetric flow rate (Q in CFM or m³/h), engineers calculate total internal electrical power loss ($P_v$ in Watts) and set an acceptable internal temperature delta ($\Delta T = T_{internal} - T_{ambient}$):
$$Q_{\text{CFM}} = \frac{3.16 \times P_v (\text{Watts})}{\Delta T (^\circ\text{F})}$$
$$Q_{\text{m}^3/\text{h}} = \frac{3.1 \times P_v (\text{Watts})}{\Delta T (^\circ\text{C})}$$
$$Q_{\text{m}^3/\text{h}} = \frac{3.1 \times P_v (\text{Watts})}{\Delta T (^\circ\text{C})}$$
Underestimating internal heat generation by ignoring VFD harmonics or solar load on outdoor enclosures frequently results in under-sized cooling systems that fail under full load.
