static pressure (in. Density of air 6356 x Efficiency Density of standard air Small fans 0.40 – 0.50 efficiency Large fan 0.55 – 0.60 efficiency For Water: 1 lb/h = 500 gpm 1 ton = (gpm) ∆t/24 gpm x ft head 3960 x Efficiency Small pumps 0.40 – 0.60 efficiency These higher efficiency levels are ideal for sustaining larger air systems. For a main forcing fan the FSP is given by the gauge static pressure at the inby side of the fan (Figure 10.1(b)). It can be expressed in these terms: The operating static efficiency range is 55-75 percent. An accurate measurement of static pressure is critical to proper fan selection. 2. per 100 feet of duct (assuming duct air velocity falls within 1000-1800 feet per 132 FAN FUNDAMENTAlS STATIC PRESSURE GUIDELINES STATIC PRESSURE GUIDELINES Nonducted 0.05 in. Fans and Blowers Bureau of Energy Efficiency Figure 5.1 Centrifugal Fan Figure 5.2 Axial Fan Centrifugal Fan: Types The major types of centrifugal fan are: radial, forward curved and backward curved (see Figure 5.3). The usual pressure range of application is 0-76 mm water (0-745 pascals) static pressure. 0.67) or a percentage value (e.g. At this point the ratio of the output power of the fan (Volume flow (m 3 /s) x Static Pressure development (Pa) and the electrical power input (W) is at its greatest and the sound pressure being produced by the fan will be at its quietest. Likewise, the static efficiency curve (%) wg) vs. flow (cfm) and represents the range of operating points that a fan will achieve at a discrete speed . 3. of a pressure survey. ε is the efficiency of the fan (which is normally between 50% and 90% dependent upon gas and design). you cannot have a factor>1.0 and Fans will assume that your fan will have an efficiency greater than 1%. to 0.40 in. Fan static pressure is measured in inches of water gauge. Enhanced durability. 4.1. Fan total efficiency (D-1) Airflow rate (D-2) Fan total pressure (D-3) Fan power input (D-4) Fan velocity pressure (D-5) Fan static pressure (D-6) Fan static efficiency (D-7) Where ηt = total efficiency ηs = static efficiency ρ= density D = diameter H = horsepower N = speed Ps = static … You may enter this value as a factor (e.g. pressure for the fan has been reached. The fan speed curve (rpm) is plotted as static pressure (in. Fan total Pressure is the pressure differential between the inlet and the outlet of the fan. They represent the year’s very best for energy savings and environmental protection. Radial fans are industrial workhorses because of their high static pressures (upto 1400 Most manufacturers' performance charts are based on Fan Static Pressure. ENERGY STAR Certified Most Efficient 2020 Ventilating Fans. w.g.) First-rate energy efficiency. The fan calculator will recognise the correct value; i.e. The air enters the fan wheel through the housing inlet, turns 90 degrees and is accelerated radially and exits the fan housing. Static Pressure. 67). The simple answer is that for main surface fans it is fan static pressure (FSP) that should be employed. The power characteristic is non overloading. These fans are durable enough to properly operate in the most corrosive and erosive environments. A fan performance spec is given as a Fan Total Pressure or a Fan Static Pressure which can handle a certain flow rate. Products that make the ENERGY STAR Most Efficient list for 2020 deliver cutting edge energy efficiency along with the latest in technological innovation. 1 . to 0.20 in. Constant airflow allows centrifugal fans to generate energy that reaches up to 84% static efficiency. Static pressure in fan systems is typically less than 2” SP, or 0.072 Psi. 5. But for a main exhausting fan the FSP is One pound per square inch is equivalent to 27.7” SP. Fan Total Pressure. Ducted 0.2 in. The power curve (bhp) shows the fan shaft power required at each flow (cfm) condition at this discrete fan speed. Axial flow fans The performance of the axial flow fan is represented in figures A.6 and A.7 of Appendix "A". Axial fans use a propeller, having two or more blades, to move air in an axial direction through a cylindrical housing or formed orifice panel. Centrifugal fans are typically used for lower flows and higher pressures.