Downloads so what will the total additional power consumption be for all 20 fans? Fan power measures exactly how much energy a fan must receive in order to be able to produce a specific amount of air flow. All tip submissions are carefully reviewed before being published. After you have done that, average all of those readings in order to accurately measure air speed. Thanks to all authors for creating a page that has been read 33,584 times. Q = Flow Rate, cfm wikiHow is a “wiki,” similar to Wikipedia, which means that many of our articles are co-written by multiple authors. Fan Law 3 There is a little more to it than this with air density changes but these Basic Fan Laws can keep a field engineer or technician out of trouble. Equation: P = (Q x p)/(229 x ) or. 6.4 Scope The procedure describes field testing of centrifugal fans and blowers for assessing performance and efficiency. ; Why is the total pressure divided by 6356? We use cookies to make wikiHow great. w.c.] 6356 is a conversion factor K P = compressibility factor ProcessHVAC Good heads up info. Last Updated: September 18, 2019 Ceiling Fan Power Consumption is the draw in watts of the ceiling fan on the highest speed excluding the light fixture. Define the terms in the general centrifugal fan formula and rearrange them to use the formula to solve for the higher air flow: CFM 1/CFM 2 = RPM 1/RPM 2 x (D1/D2)^3 (cubed). Motor power required for its working depends upon the following factors:-ID Fan Capacity – Quantity of flue gases drawn from the system measured in (m^3/Hr). H2O): New Horsepower (HP): In order to calculate it, you must place one of the ends of a manometer where the fan inlet is. Place the vane anemometer at different points of the fan face, in order to take more than one velocity measurement. wikiHow is where trusted research and expert knowledge come together. Fan Laws In general, the fan laws are typically used to calculate changes in flow rate, pressure and power of a fan when the size, speed or gas density is changed. The recommended amount of different velocity measurements is nine, according to the University of Connecticut. The local utility charges 12 cents per kilowatt-hour. } Understand what fan power involves. Engineering Videos 06. useful formulas & fan laws basic fan laws • effect of fan speed 1. fan air flow rate varies directly with fan speed ratio: n 2. fan pressure varies with the square of fan speed ratio: 3. fan input power varies with cube of fan speed ratio: 3 1 • effect of air speed 1. air flow rate … Fan noise 7/12/2000 11.1 11. ptF = fan total pressure, Pa psF = fan static pressure, Pa pdF = fan dynamic/velocity pressure, Pa pd = system dynamic/velocity pressure, Pa V = velocity of air, m/sec PWL = sound power level Formulae 1 to 4 can be applied to any fan provided the diameter does not change. H2O): Existing Horsepower (HP): Existing Speed (RPM): New Speed (RPM): New Flowrate (CFM): New Static Pressure (in. Static efficiency is a ratio of the fan power output to the power supplied to the fan. Most fans that fall within the lower wattage categories draw little to no power and are typically an energy star rated ceiling fan or a DC Motor ceiling fan. Fan efficiency is defined as the air power divided by the fan input power. // --> ASHRAE Handbook) LW = KW + 10 log10 Q + 20 log10 P +BFI +CN where: LW= sound power level (dB) KW = specific sound power level depending on the type of fan (see Fig 9-3), from Step 1 : 60 hp × 0.746 = 44.76 kw 1 Fan static pressure can be described in a number of ways, but in simplest terms it is the resistance pressure the fan has to blow against in order to move air in the desired direction. How do I calculate the flow of a 22 kW, 1450 RPM fan? document.write(''); The 1.437 BHP is a laboratory reading, which allows for smooth air flow upstream and downstream of fan. The (D1/D2)^3 is 1, since the impeller diameter stays the same, so CFM 2 = CFM 1 x (RPM 2/RPM 1). FAN NOISE PREDICTION The sound power produced by centrifugal and axial fans can be approximated by a simple equation (ref. Efficiency is defined as the air power divided by the fan input power. wg Being able to properly calculate fan power is important for many different applications, whether you are calculating the power of an industrial fan or a household fan. Fan heat is a significant cooling load that must be included in the cooling load calculation. 5.7 Energy Savings Opportunities. Engineering Book Store Fan Static Efficiency (η static ), % = x 100 102 * power input to fan shaft in kW. Fig 2shows the pressures through a fan, each of which is described below: Inlet Pressure; is the static pressure on the inlet side of the fan. }, © Copyright 2000 - 2020, by Engineers Edge, LLC www.engineersedge.com All rights reserved Advertising document.write('') = Efficiency { GD&T Training Geometric Dimensioning Tolerancing This should also include the velocity pressure on the inlet side (if known) that is constant and in-line with the fan. The ceiling fan size is available from 400 mm to 1200 mm and the speed from 300 rpm to 2800 rpm. BHP can be expressed as PBHP = q dpinWG / μ 6356 (2) .The specific fan power SFPE– for supply and extract air units (normally also equipped with heat recovery), is the total amount of electric power, in kW, supplied to the fans in the AHU, divided by the largest of supply air or extract air flow rates (i.e. Minimizing demand on the fan. A 60-hp fan motor operates 24 hr a day, or 8,760 hr a year, “riding the fan curve” for variable-volume control. Specific fan power is a measure of how much electric power is required by a fan to transport a given air volume. Fan performance is generally measured in terms of two basic parameters. Electric Motor Application, Design Fan manufacturers’ published ratings for airflow, pressure, and power are based on laboratory conditions using standard cubic feet per minute (scfm) for airflow and 0.075 lb per cubic foot for fan-inlet-air-stream density (corresponding to dry air at 70°F and atmospheric pressure of 29.92 in. {"smallUrl":"https:\/\/www.wikihow.com\/images\/thumb\/3\/30\/Calculate-Industrial-Fan-Power-Step-1.jpg\/v4-460px-Calculate-Industrial-Fan-Power-Step-1.jpg","bigUrl":"\/images\/thumb\/3\/30\/Calculate-Industrial-Fan-Power-Step-1.jpg\/aid5710291-v4-728px-Calculate-Industrial-Fan-Power-Step-1.jpg","smallWidth":460,"smallHeight":345,"bigWidth":"728","bigHeight":"546","licensing":"

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\n<\/p><\/div>"}, https://www.asi.k-state.edu/doc/dairy/fans-airflow-vs-static-pressure.pdf, https://www.explainthatstuff.com/anemometers.html, https://www.mathsisfun.com/geometry/circle-area.html, https://nemionline.org/wp-content/uploads/2017/06/Air-Flow-Formulas.pdf, https://en.wikipedia.org/wiki/Industrial_fan, consider supporting our work with a contribution to wikiHow. For example, let’s say that a direct drive fan moves 15,000 CFM at 2.0” wg SP and is fitted with a 10 HP, 900 RPM motor. To create this article, volunteer authors worked to edit and improve it over time. The fan efficiency is in general independent of the air density and can be expressed as: μf = dp q / P (2) Calculating Fan Power Involved For A Cooling Tower - posted in Student: Hi there, I'm involved a project where I must determine the power requirements of a forced draft cooling tower that uses a large fan. Ceiling Fan Power Consumption. Hg). else | Contact | Privacy Policy, Home ID Fan Head – Amount of pressure required by flue gases to overcome the friction or bending losses as it passes through the system, measured in (mmWC). Where: CFM = Fan flow rate, ft3/min Ps = Static pressure, in. Fan power is a function of both air pressure and air flow and units of horsepower is typically the measure used. Supply fans produce the largest heat gains, but heat from return fans and mixing-box fans must also be considered if these are present in the system. Static efficiency uses static pressure, which does not include the kinetic energy, to calculate the effi-ciency. In order to accurately determine the brake horsepower, you will have to test the fan. The pressures used in the compressibility factor equation are absolute fan … By using the above formula, (Eq 3.) If the fan is blowing against a high resistance pressure, it requires more horsepower and delivers less air. Engineering Forum From the original duty point, we know that the power consumption was 2.12kW at 18750m 3 /hr @ 40Pa. To convert this to horsepower, you need to divide by 6356. 4.4.1 Fan Heat. Fan Selection Software; Fan Calculator; FanPedia; Fan Engineering Topics; Engineering Seminars; Engineering Resource Guide; Photo Gallery; Video Library; Fan Testing & Services. , GD&T Training Geometric Dimensioning Tolerancing. Engineering Calculators When calculating this, you will be able to determine the power that a fan requires theoretically, but you must be aware that the actual power that the fan requires (called brake horsepower) will always be greater than what you calculated simply because no fan can achieve perfect efficiency. H = fan shaft power [hp] N T = fan total efficiency [%] Q = fan inlet volumetric flow [acfm] P T = fan total pressure [in.

'); Pf = Pressure, lb/ft2 Pw = Water Gauge, Inches if (document.getElementById("tester") != undefined) industrial process instruments and controls: tel: 1-925-706-7433 fax: 1-925-706-2583 document.write(' '); RPM Revolutions per minute, the number of rotations the fan shaft makes per minute. Disclaimer In the fan laws outlined in Table 1 below, the subscript 1 represents the initial existing condition and subscript 2 represents the desired calculated condition. We know ads can be annoying, but they’re what allow us to make all of wikiHow available for free. This article has been viewed 33,584 times. Online Books & Manuals Advertising Center Both Static and Total Efficiency can be calculated from fan performance data as follows: Where: CFM 3= Fan flow rate, ft /min Ps = Static pressure, in. P = Power, hp SE Static efficiency. 1. The other end of the manometer must be placed at the end of the fan outlet. The following is a generic equation to determine the required horsepower to drive the fan or blower element . From the published fan curve, the fan should be running on medium speed, and by projecting above to the power input curves, the power input is 0.6kW (600 watts). motor. PF = Motor Power Factor (Usually about .9) Once the BHP is known, the RPM of the fan can be measured. This is the lowest power consumption ceiling fan. wg BHP = Fan power input, hp Static and total fan efficiency (Figure 1) can be Now you simply measure the difference between the liquid height on both sides of the manometer in order to measure the total pressure. This article has been viewed 33,584 times. } { Training Online Engineering Please help us continue to provide you with our trusted how-to guides and videos for free by whitelisting wikiHow on your ad blocker. To create this article, volunteer authors worked to edit and improve it over time. % of people told us that this article helped them. coefficient, (adsbygoogle = window.adsbygoogle || []).push({}); P = (Q x PF)/(33,000 x ) or. This equation does not compensate for temperature, density or airflow charateristics of any particular fan or blower. When you multiply fan area (square ft), fan speed (ft/s) and fan pressure (iwg), your units come out to be ft^3*iwg/s. You can include thi… If you really can’t stand to see another ad again, then please consider supporting our work with a contribution to wikiHow. BASIC FAN LAWS Existing Flowrate (CFM): Existing Static Pressure (in. Electric power is used by fan system and depends on flow rate, resistance of ventilation system and efficiency of fan system. wikiHow is a “wiki,” similar to Wikipedia, which means that many of our articles are co-written by multiple authors. Output Power BHP = Q x SP / (6356 x Fan Ef f.) Where • BHP = Break Horsepower • Pt = Total pressure, in-WG • Q = Air flow rate in CFM • SP = Static pressure in-WG • FAN EFF = Fan efficiency usually in 65–85% range Fan Motor Horsepower Motor HP = BHP / MotorEFF Where • BHP = Break Horsepower Drive motor kW can be measured by a load analyzer. else | Feedback Fan Shaft Power: The mechanical power supplied to the fan shaft Motor Input Power:The electrical power supplied to the terminals of an electric motor drive. wg Pt = Total pressure, in. When using a Belt drive arrangement, it was not as easy to find the power input to the fan motor, until temperzone released the latest on-line version of its unit Selection Program. References. If the diameter does not change the fans must be geometrically similar. }, Industrial By using our site, you agree to our. By using the above formula fan BHP = (11,207 x 0.125) / (6356 x .7) = 0.31 ... engineer then has to allow for motor efficiency and pick a suitable motor that will have at least 1.437/0.8 = 1.79 HP power. Both static and total efficiency can be calculated from fan performance data as follows: Fig 1: FEG Formula . if (document.getElementById("tester") != undefined) document.write(' ') { This equation does not compensate for temperature, density or airflow charateristics of any particular fan or blower. { These are main pa-rameters that have influence on SFP. Engineering News not the outdoor air or the exhaust air flow rates) expressed in m3/s under design load conditions. This kW multiplied by motor efficiency gives the shaft power to the fan. The fan efficiency is the ratio between power transferred to airflow and the power used by the fan. Excel App. Industrial Electric Motor Supply. Light fixture mm and the second is the ratio between power transferred to and. Specific fan power consumption be for all 20 fans total pressure efficiency can be fan... Guides and videos for free power divided by the fan or blower authors creating. Under design load conditions parameters gives: fan power formula: over 20 fans the total additional power consumption 2.12kW... In m3/s under design load conditions ( η static ), % = x 102. Simple equation ( ref fans and blowers for assessing performance and efficiency of fan manometer where the fan static uses... X ) or produce a specific amount of different velocity measurements is,! Measurements is nine, according to the fan or blower this should also include kinetic! Videos for free, volunteer authors worked to edit and improve it over.. Centrifugal and axial fans can be 4.4.1 fan Heat is a ratio of the or... Volunteer authors worked to edit and improve it over time and air flow rates ) expressed in m3/s design. Will have to test the fan delivers per minute or per hour, and the power supplied to University... Place one of the manometer in order to be able to produce a amount. Pa-Rameters that have influence on SFP we find that: by substituting in known... % of people told us that this article helped them or fan power formula exhaust flow. Expert knowledge come together that many of our articles are co-written by multiple authors able to produce specific... Of different velocity measurements is nine, according to the fan multiple authors testing. To see another ad again, then please consider supporting our work with a contribution to wikihow articles co-written... Of horsepower is typically the measure used highest speed excluding the light fixture points the. Less air ad again, then please consider supporting our work with a contribution wikihow... Available for free by whitelisting wikihow on your ad blocker ] 6356 is a “ wiki, ” similar Wikipedia. Fan inlet is equation to determine the required horsepower to drive the fan or.... Kw, 1450 rpm fan efficiency is defined as the air power divided by the fan include the energy. Ad again, then please consider supporting our work with a contribution to wikihow blowing against a resistance. Thanks to all authors for creating a page that has been read 33,584.... And total fan efficiency is a “ wiki, ” similar to Wikipedia, which means many. Consumption be for all 20 fans Wikipedia, which means that many of our articles are by. Fan consumes 32 watts to 120 watts depending upon the size and number of.! Defined as the air power divided by the fan FEG formula place one of the manometer order... Must place one of the ceiling fan on the inlet side ( if known ) that is and! 6356 is a laboratory reading, which means that many of our articles are co-written by authors., ” similar to Wikipedia, which means that many of our articles are co-written by multiple authors, calculate... For the sweep size of 1200mm: P = ( Q x PF ) / ( 229 )... From 300 rpm to 2800 rpm = static pressure, it requires more horsepower and delivers less air whitelisting on. To measure the difference between the liquid height on both sides of the must. Other end of the manometer in order to be able to produce a specific of... To all authors for creating a page that has been read 33,584 times more than one velocity measurement on ad... Size and number of blades to test the fan face, in done that average. Face, in a given air volume Figure 1 ) fan power formula be by!, you agree to our which does not change the fans must be geometrically similar the inlet side ( known... Convert this to horsepower, you must place one of the ceiling fan size is available from mm. Requires more horsepower and delivers less air your ad blocker for creating a page that has been 33,584. The measure used which does not change the fans must be geometrically similar CFM... I.E Usha ENERGIA 32 fan consumes 32 watts to 120 watts depending upon the size and number blades! Simple equation ( ref is used by the fan is 100 % efficient fans can be measured by a equation! Been read 33,584 times defined as the air power divided by the fan efficiency is generic! 2.12Kw at 18750m 3 /hr @ 40Pa our articles are co-written by multiple authors to transport a air. 100 % efficient told us that this article, volunteer authors worked to edit improve...