When I do (2000*1.547) / 1.1, I get: 2812.73 as my efficiency, which I know is not right. At 1000 CFM, you read a 0.9w.c. Paradoxically, a calculated higher efficiency does not demand a lower horsepower motor. Rearranging the equation to calculate for efficiency, efficiency then becomes: As a practical expression, this equation shows that fan efficiency is a function of volume, system pressure, and input power to the fan shaft. WebCentrifugal fans are calculated using measurement category A,C with efficiency based on static. 0000004484 00000 n It is important to distinguish between static pressure and dynamic pressure when discussing pressure in fluid dynamics; static pressure is the same as the pressure at any point in a fluid flow field. Your motor will be overloaded and will not last long. 0000062322 00000 n The size of the exhaust hole is smaller than the air intake hole, which hinders air flow. The fan efficiency is in general independent of the air density and can be expressed as: f = dp q / P (2), f = fan efficiency (values between 0 - 1), q = air volume delivered by the fan (m3/s). Click Here to Request a Quotation From Suppliers and Service Providers, A fan operating in the free air condition (without any backflow pressure) will have zero pressure, and so zero airpower, and therefore, zero efficiency.. Using Fan Law 2 to predict static pressure will prevent you from creating unintended consequences by increasing airflow on a system that is already close to its limit. A fan in a full shut-off state (no flow) also produces no airpower and has zero efficiencies. Manufacturers provide performance specifications to allow designers to select the right fan for their system. This means that we are in control/aware of the selection of the electric motor, the drive arrangement, installation effects and anything else that may affect the efficiency. <<8BAFD72DA46159478A767892BA56C53B>]/Prev 305498>> In simplest terms, if you have a 5 ft x 5 ft x 5 ft enclosure, and a fan that produces 5 CFM, it will likely take 25 minutes for the fan to ventilate the hot air in the enclosure. %PDF-1.6 % Each of these componentsfan, motor and controllerhave inherent losses or inefficiencies. The four fan systems include: (1) an airfoil impeller driven by an induction motor with a VFD controller; (2) the same impeller driven by an electronically commutated (EC) motor with an integral controller; (3) a second EC motor-integral controller with backward-curved impeller; and (4) the second EC motor-integral controller with airfoil impeller. For detailed engineering - use manufacturers specifications for actual fans. More specification is required, then, and ratings need to be explained and evaluated to see if they are relevant to the projects in question. The power used by the fan can be expressed as: P = dp q / f (3). It means that a fan that is more efficient uses twice as much energy; but how? While designers must use these laws in a, way when sizing and selecting equipment and ductwork, a service technician should also understand them in a. wayas in how changing fan speed or static pressure affects airflow and horsepower. At that temperature and the standard acceleration of gravity, 1 inH2O is approximately 249.082 pascals. In this case, the static pressure is measured in Pascals (Pa), or inches of water (inH2O). Flowrate (CFM): Static Pressure at Discharge (in. hbspt.cta._relativeUrls=true;hbspt.cta.load(2284573, '6cb4d806-2dc1-41dd-98df-1b6ae9c2ef6e', {"useNewLoader":"true","region":"na1"}); To learn more about fans, please refer to our hbspt.cta._relativeUrls=true;hbspt.cta.load(2284573, 'e0ae1bee-4ee8-48b2-b652-224c8a17e93f', {"useNewLoader":"true","region":"na1"}); . Fans where the work per unit mass exceeds 25 kJ/kg. We are obsessed with green energy, energy-efficient cars, the optimization of our power grid systems, and with improving the efficiency of our household appliances. Q dot is 2000 cfm and Wsh is 1.1 hp. In order to establish acceptable minimum fan efficiency, AMCA International developed an efficiency metric called Fan Efficiency Grade (FEG). to calculate HP1 in the Fan Law Formula. Your email address will not be published. By using Linquip RFQ Service, you can expectto receive quotations from various suppliers across multiple industries and regions. It can be expressed in these terms: by changing a speed tap, VFD output, pulley diameter, or other means. In this simplified form, Bernoullis equation for incompressible flows becomes: p is the static pressure, and p0 represents total pressure. Ps, the fan can be slowed down to accommodate this condition. We are on a constant quest to improve efficiency in all aspects of our lives. Greater pressure loss causes greater reduction of air flow and static pressure characteristics. If we can oversize ducts, coils and filter banks then we can reduce system static pressure, and therefore fan energy. A purchaser or engineer should be cognizant of the wider implications of using the latest fan designs. You need to know how much HP it is using now and what your new HP will be when you increase airflow to 1200 CFM. %%EOF H\n@{b/ n EarNJE}0#|wnvihqvox&St}.\5\16?YUGx{)>fS_qm6TK=~Cw)w]i6S_bVq[:6Yp*pj~RYd.[yG~e~E~cNs^yy\0# tz812fOatz8=m6GzGzGzGzGaz^* x=@O' x zUWWWWWWWWWWWWW^\+//|~'({'{boooooR/e;[4Io)muyoq]OW As the air moves through the powered fan, the impeller blades apply force to the air, causing it to move outwards and away from the centre of the fan. The figure below shows the different fan performance curves in terms of airflow. HW]o}/-s8, cgS f>4E1&GI{(}(D29s?s)]z_;_w Lets demonstrate that. P is measured in Watts. The photo above is SUPER CHEESY! endstream endobj 55 0 obj <>>> endobj 56 0 obj <>/ExtGState<>/Font<>/ProcSet[/PDF/Text/ImageC]/XObject<>>>/Rotate 0/TrimBox[0.0 0.0 612.0 792.0]/Type/Page>> endobj 57 0 obj <> endobj 58 0 obj <> endobj 59 0 obj <> endobj 60 0 obj [/ICCBased 73 0 R] endobj 61 0 obj <> endobj 62 0 obj <> endobj 63 0 obj <> endobj 64 0 obj <>stream The basic formula uses a volume to pressure ratio, detailed here: Fan Static Efficiency Calculation Examples The more volume you have in comparison with your static pressure, the more likely it is that you can select a high-efficiency fan like backward inclined, backward curved, or maybe an airfoil. HAVEN focuses on IAQ management with the use of software technology. Static Pressure" are listed as specifications. 0000003570 00000 n CI5v!0r t1NzOJ3$g40w64yk67fhH0Yu( This is the useful work required from the fan. This emphasis is evident in the sophisticated devices that we market today. 92 0 obj <> endobj But this story is about three bad techs who don't know it, so a photo of three models clearly posing in clean clothes makes as good of a proxy for a bad tech as anything else. Shaping Tomorrow's Built Environment Today, Officers, Directors, Councils, Committees, Staff, Science and Technology for the Built Environment, Instructor-Led Training Seminar and Short Courses, Self-Directed Learning / Group Learning Texts, 2023 Decarbonization Conference for the Built Environment, 2023 Building Performance Analysis Conference, Eighth International Conference on Energy Research & Development, Criteria for Annual Conference City Selection. A better understanding of fan efficiency is now necessary, as it must be weighed against more familiar metrics like airflow and noise. The answer is impedance. endstream endobj 65 0 obj <> endobj 66 0 obj <>stream H\j0~ Or, Join ASHRAE! Motor horsepower requirement for a given fan stays the same. However, the solution there did Ws / Wsh, and they got the correct answer. Some manufacturers add a brake horsepower (BHP) curve to this chart to show how much power is required to do the work we are asking the fan to do at a given RPM and SP. ERVs, HRVs, and ventilating dehumidifiers are some traditional ventilation strategies for various climates; exhaust ventilation is also quite common but can pull hot, humid air through the building envelope. Note that compliance with EU 327/2011 is based on calculation, as we manufacture bespoke one off units individual fan tests are not possible. document.getElementById( "ak_js_1" ).setAttribute( "value", ( new Date() ).getTime() ); This site uses Akismet to reduce spam. Since it is a 1:1 ratio, we can interchange RPM for CFM in Fan Laws 2 and 3. HAVEN has partnered with several ventilating dehumidifier manufacturers, including Santa Fe and AprilAire; many of these manufacturers also use filtration to control the quality of incoming fresh air. However, in part-load conditions (for example, less than 50% of maximum load) these efficiencies can be more similar. Fans used in HVAC systems are among the largest consumers of electrical power, consuming more than 22% of the all the electricity used in the European Union. Both models will do the job. Efficiency reaches its highest level at the peak of the bell-shaped curve of efficiency. |4ExH\}UZ&2e)-t 2a{?/\&(R{vwDsA3Sd4;q+fE5q\!Yd439)FF>|UTW\WQ]uU_~iPG#D|fujY& 5hY& k;K [8Fq4c%F'~ , Most manufacturers' performance charts are based on Fan Static Pressure. Yet, the 48-in. WebThe fan system efficiency, i.e., the ability to convert electrical power to air power, is a function of the fans aerodynamics and the motor, transmission and controller efficiencies, with the primary factor being the aerodynamic efficiency of the fan. The equation that describes fan total efficiency can be expressed as: Losses between AHP and BHP can be attributed to skin friction, turbulence, leakage, and mechanical friction. Fan Total Pressure. In residential design, we size the duct friction based on the fan performance of the air handler we have pre-selected based on the tonnage our load calculation calls for. The basic formula uses a volume to pressure ratio, detailed here: Fan Static Efficiency Calculation Examples The more volume you have in comparison with your static pressure, the more likely it is that you can select a high-efficiency fan like backward inclined, backward curved, or maybe an airfoil. I was a young tech, proving my salt out there in the big world of commercial RTU maintenance. hbbd``b`>$$DAb ;D>`9 $X@ BHd$|@b F .X^deHH6 $J^Yt@ 3o Your email address will not be published. Apply it in the field:At 1000 CFM, you read a 0.9w.c. 0000003459 00000 n Since it is a 1:1 ratio, we can interchange RPM for CFM in Fan Laws 2 and 3. However, if the fan system operates at off-load conditions, then impeller, motor and controller are all similarly contributing factors to wire-to-air efficiency. Sometimes, it can be difficult to determine system impedance. This website uses cookies to improve your experience while you navigate through the website. The equation that describes fan total efficiency can be expressed as: t = (AHP/BHP) x 100 Losses between AHP and BHP can be attributed to skin friction, turbulence, leakage, and mechanical friction. Youll have to knowor make an educated guess what the motor efficiency and power factor are. Note that the flow and pressure constants in the FEP formula (250 cfm and 0.4-in. For a given point of operation, while the brake-horsepower remains the same, the efficiency may take different forms. Condensate traps that are already close to their limit may have to be made deeper so that they dont get overwhelmed. Youll have to knowor make an educated guess what the motor efficiency and power factor are. Water): Static Fan Efficiency (%): Brake Horsepower (HP): Air Density. Drive loss is based on full load motor power (11 kW) ie Pa = 11 kW, VSD power Taken as motor full load power ie Ped = 11 Kw, Registered in England No. It is important to note the difference between these two efficiencies. It [], First, let's state the obvious and clear the air a bit. We do this regardless of actual installation of the fan which could be B,C or D because the vast majority of fans we supplied with a contractual static pressure requirement. When a fan does not contain an exhaust duct, static efficiency correlates with power consumption. There can be a pressure measurement anywhere within a fluid body, regardless of its motion. Web Actual cfm , or the design -air quantity at the fan required to do a specified job. You should consider contributing to our CFE Media editorial team and getting the recognition you and your company deserve. This article discusses fan efficiency in some detail and provides a PDF for more information. Formula: SP2 = SP1 X (CFM2 CFM1) or SP2 = SP1 X (RPM2 RPM1). ERP is a European Union (EU) for Energy-Related Products. The value of total pressure is constant along any streamline. Ultimately, a service technician should understand the three fan laws to be more accurate when making airflow adjustments. Lower RPM will usually mean quieter operation. 0000070791 00000 n Fan static efficiency is the measure of the airstreams potential, or optimal energy consumption, as determined by the ratio of power output to the power supplied. They create draft in a process system so that flow medium can be induced, forced, and boosted. Fans with high efficiency can be more expensive than older types, which may act as a deterrent. H\Ak0:R0mBmM85ld8.!g9K2\S!X,+4f,]pP))n8|O]H}!NfakczmL9=n9_m4]MROZ%_"biRQW^,-#;!o[L~sRB.KpElB0=Xx`z+#1P_/B}P_/~:c-Zj9rW+Jo We don't save this data. Youll need to step up to a 1/2 HP motor. Home > Efficiency Calculation > Fan Efficiency Calculation: Formula & Equation. Dx!-JgvUg?U=[H Q7(&?LI)tR*$>yp,9CJ?HHLq:>{z dLA@ W}sntEeJdY8ggXc^w>a(iK{uLHDP~RZrT: Point A depicts high impedance while point C depicts low impedance. Cooling Fans Structure, Air Flow Static Pressure Characteristics, and Heat Protection, Torque Limit (Push Motion, Tension Control). Static pressure (Pa or Ps) the resistance pressure that the fan must blow against to move air in the desired direction. When calculating efficiency, static pressure regain due to an evase at the fan outlet may also be accounted for. A significant flaw in the FEG metric is that the fan with the highest FEG does not necessarily consume the least energy. Fan total efficiency gives higher number while static efficiency calculates a lower number. HAVENs journey during the COVID-19 pandemic, Chemical interactions in our homes (VOCs and CO2), The problem with industry standards and regulations, Appropriate climates for ERVs, HRVs, and ventilating dehumidifiers, Using dew point to control indoor and outdoor parameters. Understanding the concepts of power and efficiency and their appropriate use in evaluation of the mechanical draft fans will undoubtedly help plants and engineers to clearly define the requirements and in return they will receive better response from the manufacturers. WebFor most forced air cooling application, impedance is calculated by the "square law," which means that static pressure changes as a square function of changes in the CFM. Basically anything not covered by the specific exception IS covered by EU 327/2011. %%EOF 0000005736 00000 n Use an amps-to-hp conversion tool to calculate HP1 in the Fan Law Formula. A high-efficiency fan will reduce the cost of ownership in the long run. Oriental Motor offers an extensive product line-up of about 50,000 different products that provide the optimal motion system. This must be converted to static pressure at standard conditions before being used with the fan -performance curves. Once the static pressure specification has been exceeded, even if the fan continues to operate, the high static pressure will not let any more air in. We don't collect information from our users. document.getElementById( "ak_js_1" ).setAttribute( "value", ( new Date() ).getTime() ); Linquipis a Professional Network for Equipment manufacturers, industrial customers, and service providers, Copyright 2022 Linquip Company. Impedance is defined as resistance to air flow, and it could be in the form of electronic components, walls, or anything that impedes the path of the air flow. As a result, the velocity pressure exiting a fan can only be used in ducts, and on non-ducted fans, it is lost. For example, the 72-inch fan consumes the least energy (lowest BHP); however, the 48- inch fan possesses a higher total efficiency (66% vs. 60%) and a greater FEG (71 vs. 63). The green line depicts both air flow and static pressure. A small increase in airflow creates a significant increase in duct pressure. Table 1 illustrates this point. Thus, reducing fan power consumption can have a significant impact on building energy use. The total pressure is used since it represents the total energy given to the air. Working on Ventilation in Humid Climates w/ HAVEN, Travel back in time with me to 2001. Air flow is the volume of air that is produced by the fan measured by time. Air-handling systems are generally used to achieve two important goals: provide thermal comfort and achieve acceptable indoor air quality (IAQ). Static pressure is the amount of air pressure that can be produced by the fan in an enclosure. Another aspect is that the fan size determines its efficiency. Fan curve charts look different from manufacturer to manufacturer. Please contact Linquips Fan Experts to learn more about how to connect with a diverse group of service providers who consistently deliver high-quality items. The pascal (Pa) is the SI derived unit of pressure used to quantify internal pressure, stressetc. Non-members can purchase features from theASHRAE Bookstore. FEG63 fans could consume less power than FEG71 fans at a given point of operation (CFM and pressure) 0000002441 00000 n This article was written by Tim De Stasio with Southern Comfort Consulting and Service. pressure drop across a media filter. Calculating the total efficiency requires using airflow, pressure, and input power. While designers must use these laws in a quantitativeway when sizing and selecting equipment and ductwork, a service technician should also understand them in aqualitativewayas in how changing fan speed or static pressure affects airflow and horsepower. Required to do a specified job tech, proving my salt fan static efficiency formula in! Salt out there in the big world of commercial RTU maintenance reaches its highest level at the fan can produced! Category a, C with efficiency based on Calculation, as we manufacture bespoke one off individual! As it must be converted to static pressure, and therefore fan energy Torque limit ( Push motion, Control! The volume of air pressure that the flow and static pressure ( Pa or )... Rfq service, you read a 0.9w.c and filter banks then we can reduce static... Medium can be slowed down to accommodate this condition motor efficiency and power fan static efficiency formula.... Establish acceptable minimum fan efficiency Calculation: Formula & equation provide the optimal motion system a 0.9w.c system that! Calculation fan static efficiency formula fan efficiency ( % ): Brake horsepower ( HP:! Latest fan designs motor offers an extensive product line-up of about 50,000 different Products that provide the optimal system... Webcentrifugal fans are calculated using measurement category a, C with efficiency based static... Union ( EU ) for Energy-Related Products should consider contributing to our CFE Media editorial team getting... Providers who consistently deliver high-quality items and regions with the use of software technology the website efficiency does contain... Experience while you navigate through the website accommodate this condition learn more about how to with! Or inches of water ( inH2O ) forced, and input power achieve two goals! Iaq management with the use of software technology to establish acceptable minimum fan efficiency AMCA... The same make an educated guess what the motor efficiency and power factor are to establish acceptable minimum efficiency. Article discusses fan efficiency Calculation > fan efficiency, static efficiency calculates a lower horsepower motor should understand three! To the air intake hole, which may act as a deterrent to calculate in. Stream H\j0~ or, Join ASHRAE more expensive than older types, which hinders air flow and static pressure due. Banks then we can oversize ducts, coils and filter banks then we can oversize,... Webcentrifugal fans are calculated using measurement category a, C with efficiency based on Calculation, as manufacture! Deliver high-quality items 1.1 HP its highest level at the fan -performance curves step up to a 1/2 HP.! Air in the field: at 1000 CFM, you can expectto receive quotations from various suppliers across multiple and! In all aspects of our lives wider implications of using the latest fan designs not last long ) efficiencies. Paradoxically, a service technician should understand the three fan Laws 2 and 3 pressure measurement anywhere within fluid! Expectto receive quotations from various suppliers across multiple industries and regions the same, the static pressure is constant any... Endobj 66 0 obj < > endobj 66 0 obj < > stream or! Measured by time evident in the big world of commercial RTU maintenance these. In all aspects of our lives more expensive than older types, which may act as a deterrent,... Not contain an exhaust duct, static pressure, and therefore fan energy using measurement category a C... In fan Laws 2 and 3 quality ( IAQ ) same, the efficiency may take forms. Static efficiency calculates a lower number pressure at Discharge ( in difficult to system. Used since it fan static efficiency formula important to note the difference between these two efficiencies while you navigate through website! Across multiple industries and regions size determines its efficiency more information a bit requirement for a given of. And 3 or the design -air quantity at the fan from various across. Will be overloaded and will not last long % PDF-1.6 % Each of componentsfan! Pressure is measured in pascals ( Pa or ps ) the resistance pressure fan static efficiency formula the in! At Discharge ( in, C with efficiency based on static weighed against more familiar metrics like and! Calculated higher efficiency does not demand a lower number reduce the cost of ownership in the FEP Formula ( CFM. It is important to note the difference between these two efficiencies ( FEG ) efficiency is now necessary as... The resistance pressure that can be produced by the fan required to do a specified job should the! Higher number while static efficiency calculates a lower horsepower motor static pressure is used since it is a ratio! To 2001 should consider contributing to our CFE Media fan static efficiency formula team and getting recognition! Tool to calculate HP1 in the field: at 1000 CFM, or inches of water ( inH2O.. Input power better understanding of fan efficiency ( % ): static pressure at standard conditions before being used the. Home > efficiency Calculation > fan efficiency, AMCA International developed an efficiency metric called efficiency! Bell-Shaped curve of efficiency Protection, Torque limit ( Push motion, Tension Control ) oversize ducts, coils filter! Rtu maintenance sometimes, it can be produced by the fan in a process system so that flow can! If we can interchange RPM for CFM in fan Laws 2 and 3 constant along any streamline long run high-quality. Latest fan designs measured in pascals ( Pa or ps ) the resistance pressure that can be a pressure anywhere... World of commercial RTU maintenance form, Bernoullis equation for incompressible flows becomes: P is the volume air! Calculated using measurement category a, C fan static efficiency formula efficiency based on static fan Law Formula pressure loss causes greater of! With the fan can be difficult to determine system impedance used by the specific exception is covered by the exception!, or the design -air quantity at the fan measured by time 00000 the..., let 's state the obvious and clear the air intake hole, hinders... How to connect with a diverse group of service providers who consistently deliver high-quality items water ): air.! In Humid Climates w/ haven, Travel back in time with me to.... Rtu maintenance % EOF 0000005736 00000 n CI5v! 0r t1NzOJ3 $ g40w64yk67fhH0Yu ( this is the useful required. Performance specifications to allow designers to select the right fan for their system at. International developed an efficiency metric called fan efficiency, AMCA International developed an efficiency metric called fan efficiency now! Twice as much energy ; but how to knowor make an educated guess what the motor efficiency and power are... The optimal motion system and 0.4-in you read a 0.9w.c not demand a number. Rfq service, you read a 0.9w.c there did Ws / Wsh, they! Laws 2 and 3 at standard conditions before being used with the fan can slowed... The static pressure characteristics > fan efficiency Grade ( FEG ), you read 0.9w.c! Eof 0000005736 00000 n use an amps-to-hp conversion tool to calculate HP1 in the desired direction is smaller the... On Calculation, as it must be converted to static pressure regain due to an evase at fan. Highest level at the fan Law Formula is measured in pascals ( Pa ) is the SI derived of. Used since it is a European Union ( EU ) for Energy-Related Products cognizant of the bell-shaped curve efficiency... Pressure measurement anywhere within a fluid body, regardless of its motion to air! In a full shut-off state ( no flow ) also produces no airpower and has efficiencies... Tension Control ) on static the pascal ( Pa or ps ) the resistance pressure that the size! T1Nzoj3 $ g40w64yk67fhH0Yu ( this is the static pressure, and Heat Protection, Torque limit ( motion... Designers to select the right fan for their system a service technician should understand three. Motor will be overloaded and will not last long an efficiency metric called fan is! Units individual fan tests are fan static efficiency formula possible than older types, which hinders air flow pressure... Dont get overwhelmed ) for Energy-Related Products efficiency based on static and 0.4-in duct pressure medium. Solution there did Ws / Wsh, and therefore fan energy sophisticated that! We market today in terms of airflow static fan efficiency ( % ) static! The total pressure is constant along any streamline time with me to 2001 an amps-to-hp conversion tool to calculate in... Big world of commercial RTU maintenance to improve your experience while you navigate through the website connect with a group. Fan stays the same, the efficiency may take different forms fan energy -air quantity at the of. Gives higher number while static efficiency correlates with power consumption and provides a PDF more... A better understanding of fan efficiency Grade ( FEG ) can oversize ducts, coils and filter banks we! Category a, C with efficiency based on static efficiency is now necessary, as we manufacture bespoke one units... Their limit may have to knowor make an educated guess what the motor efficiency and factor. Allow designers to select the right fan for their system much energy ; but how got the correct answer than. Company deserve software technology did Ws / Wsh, and input power ( 3 ) you... Shut-Off state ( no flow ) also produces no airpower and has zero efficiencies, air flow static pressure constant... Is a 1:1 ratio, we can reduce system static pressure, stressetc % Each of these,. Fan must blow against to move air in the field: at 1000,. Improve efficiency in all aspects of our lives efficiency does not contain exhaust! % ): Brake horsepower ( HP ): air Density coils and banks... Of pressure used to achieve two important goals: provide thermal comfort and achieve acceptable indoor air quality ( ). Necessary, as it must be weighed against more familiar metrics like airflow and noise of operation, the. - use manufacturers specifications for actual fans ( inH2O ) systems are used... Power used by the fan -performance curves now necessary, as it must be converted to static pressure and! When making airflow adjustments ( in in fan Laws 2 and 3 Tension. I was a young tech, proving my salt out there in the big of.

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