For free air:ss
"Power in KW = " CFM x Temperature Rise (°F)
Use the maximum anticipated airflow. This equation assumes insulated duct (negligible heat loss) and 70°F inlet air at 14.7 PSIA
For Compressed air:
CFM* x Density*(lbs/cu. ft.) x Temperature rise (°F)
*At heater inlet temperature and pressure Note: If air flow is given in CFM at operating temperature and pressure it can be converted to SCFM (Standard Cubic Feet per Minute) with the following formula.
SCFM = CFM x ( P/14.7 ) x (530/T + 460) P = operating pressure (gauge pressure + 14.7) T = operating temperature SCFM = flow rate in CFM at standard conditions of 70°F and 14.7 PSIA.