Enter a fan from its submittal

A fan's duty is its airflow and the total pressure it must develop: the duct network's index run plus every component in the air path. Kelvin finds where the manufacturer's curve meets the system curve, then works down the power chain to the motor and the heat the fan puts into the air.

1. 1

   Choose New fan, give it a Fan name, and choose its Air system and Duct network. The Design airflow is the network's flow at the fan, and the Ductwork pressure its index run.

2. 2

   Under Component pressure drops, choose Add component for each coil, filter, damper and silencer, with the selection or datasheet each drop came from.

3. 3

   Under Manufacturer's curve, type the submittal's points with its Datasheet citation and Pressure column, choose the Motor efficiency class, then Save fan.

New fan fills the duty from the project's first duct network. If you choose another network, a take link under Design airflow and Ductwork copies its figures in.

• –Type each point's flow and pressure, and the efficiency or Absorbed power where the submittal gives them. An optional column has to be on every point or on none.
• –Three or more points are fitted as a least-squares quadratic, two as a straight line. Nothing is extrapolated past the points you enter.
• –From the curve library copies a curve Kelvin holds, with its speed and citation, into the table. The copy stays editable, and the record never reads the library row again.
• –Curve measured at is the speed the curve was published at. Give a Running speed and Kelvin scales the curve to it by the affinity laws. Without the curve's own speed, it is used as entered and a note says so.
• –Without a curve, Kelvin gives the duty and nothing past it: no operating point, shaft power or motor.
• –Measured at air density is optional. Given, it is compared with the air the fan handles and any difference is stated. The curve is never corrected.

Most catalogue curves are fan static pressure. Set Pressure column to Fan static pressure and give the Fan outlet area from the catalogue. Kelvin then reads the duty, which is fan total pressure, against the curve less the velocity pressure at the fan outlet, and reads the efficiency column as fan static efficiency. A static curve read as total under-selects the fan.

• –Air power is the flow times the fan total pressure. It is always shown.
• –Shaft power comes from the curve's own absorbed power, or from its efficiency. Without either, there is no shaft power, motor or fan heat. Kelvin never assumes a fan efficiency.
• –Drive loss comes from the Drive row you choose. Left unchosen, the fan is direct drive, with no drive loss.
• –The motor is the smallest rated size in the Motor efficiency class row at or above the shaft power plus drive loss. Without a class, no motor is sized.
• –Fan heat to the air is the motor's input power when The motor runs in the airstream is ticked, and the shaft power when it isn't. The air system reads it when its fan heat comes from this fan record.