CFM (Cubic Feet per Minute) is calculated by multiplying the velocity (Feet per Minute) with the area (Square Feet).
To calculate the CFM required to adequately ventilate an area, we divide the room volume by the appropriate “Minutes per Change” value. [CFM] = [Room Volume] / [Min./Chg.]
HVAC professionals use this formula: CFM = Room Area (sq. ft.) x Ceiling Height (ft.) x ACH / 60(mins).
To calculate the static pressure from CFM, divide the CFM by the area, divide the result by 4005, square this result, then finally, subtract this from the total pressure.
For every horsepower, a compressor delivers 4-5 cfm, at 100 psi pressure. In other words - a 1 horsepower compressor will output around 4 to 5 cfm at 100 psi pressure. A 10 HP unit will output around 40 to 50 cfm at 100 psi.
For example, 100 CFM at 100 PSIG. You do have some flexibility. But it comes at a cost, reflecting the relationship between flow and pressure: when you increase the pressure, you decrease the flow. And vice versa.
CFM Calculation:
Room Volume= 300 sq ft x 8 ft = 2,400 ft3. To make it two times per hour (ACH = 2), we need to deliver 4,800 ft3 per hour. CFM is an 'ft3 per minute unit. Hence, if you divide the total volume by 60, you will get 80 CFM.
Converting Flow Rate To Pressure
Divide the square root of the volumetric flow rate by the square root of the flow factor. Multiply the result with the specific gravity of the fluid passing through the system – this will give you the differential pressure.
To calculate air flow capacity of a fan in cubic feet per minute (cfm): multiply the average air speed you measured in feet/minute (fpm) by the area of the fan face in square feet. (Area of circle =þ d2/4; where d = diameter in feet).
One cfm is needed per square foot (1 cfm/sq ft) of floor area. This is the average air quantity required for a room or an entire building. This number is based upon an averaged heat load calculation for comfort cooling.
CFM Formula
CFM = (Room Volume in cubic feet) x (ACH) / 60.
This entirely depends on the application. For a residential fan you might have in your living room, a CFM of 5,000-6,000 might be totally sufficient. For large warehouses, you might want a fleet of large-diameter HVLS fans that each have a CFM of over 300,000.
Anemometers tell you air velocity. If you can measure the air velocity in a duct of a given area cross section then you can estimate the CFM (volumetric air flow) with Velocity in feet per minute times the cross section area of the duct in square feet.
Bernoulli's equation can be viewed as a conservation of energy law for a flowing fluid. We saw that Bernoulli's equation was the result of using the fact that any extra kinetic or potential energy gained by a system of fluid is caused by external work done on the system by another non-viscous fluid.
PSI can't be directly converted to GPM; these are two different units of measure. PSI measures pressure and GPM measures flow rate. But if other variables are known, the water's flow rate in GPM can be calculated with the help of the Bernoulli equation for incompressible fluid and careful unit conversion.
The relationship between the pressure in the pipe and the flow rate is proportional. That is, the higher the pressure, the higher the flow rate. The flow rate is equal to the velocity multiplied by the cross section.
The CFM to m3/hr conversion is: 1 CFM (cubic foot per minute) to m3/hr (cubic metre per hour) = 0.02832 m3/min * 60 = 1.699 m3/hr (cubic metre per hour).
The flow rate formula is the velocity of the fluid multiplied by the area of the cross-section: Q = v × A . The unit for the volumetric flow rate Q is m 3 / s . In ideal situations, the frictional forces that restrict the fluid's movement are neglected, this leads to the development of a uniform flow.
Because they measure two different things, there really isn't a CFM to PSI conversion. Most equipment today will be a high CFM air compressor. However, the total CFM performance of any machine will depend on the pressure you need.