123ArticleOnline Logo
Welcome to 123ArticleOnline.com!

ALL Technology,-Gadget-and-Science >> View Article

Fan Performance Chart

By Expert Author: Oleg Tchetchel

The fan chart is a table presentation of fan performance. It is one of the most useful tools available during the fan selection process. While multi-rating tables are convenient (see page 12), performance curves offer additional information such as - how much reserve pressure head exists between the design pressure and the peak static pressure, the maximum power the fan might draw, and the efficiency of operation.

Fan curves are based on laboratory test data and are sometimes referred to as "test curves". A typical test curve will often define the performance parameters for a specific design and size of fan, operating at a given speed, moving a gas of a given density. Inspection of this graph will show that it is actually composed of four separate curves:

Static Pressure vs. Volume Curve: This plot is the one often referred to as the "fan curve" or "characteristic curve" because it defines all the possible pressure-volume combinations the fan is capable of producing given stated conditions (i.e. rpm and gas density). Note that this curve has two regions - one marked by dashed lines and the other by a solid line. Fans must be selected so that the design point is located on a solid portion of the curve, preferably in an area of high operating efficiency. Operation on the dashed portion of the curve should be avoided as it is a zone of potentially unstable performance. For this reason it is wise to allow some reserve between the peak static pressure and the design pressure to compensate for a higher resistance to flow than anticipated by the design calculation.

Static Efficiency vs. Volume Curve: In most instances it is desirable to have a fan perform as close to its peak efficiency as possible. The static efficiency vs. volume curve illustrates the efficiency of fan performance at a glance.

Power vs. Volume Curve: This plot illustrates the power draw of the fan for any point on the characteristic curve.

System Curve: The system curve defines the volume flow rate versus pressure characteristics of the system in which a fan will be installed.

For most applications, the volume flow rate to pressure relationship is governed by the following equation, often called the "duct law":

Once the system designer has determined the system pressure loss (P) for one flow rate (CFM), it is very easy to calculate the corresponding pressure loss for any other flow rate using this "law". The system curve is not included on the performance curve when it is issued from the fan manufacturer and its determination is left to the system designer.

At this juncture it is prudent to reiterate that a fan running at a particular speed can have an infinite number of operating points all along its characteristic curve. The fan will interact with the system to produce an operating point at the intersection of the system curve and the fan curve. Note that it is the system in which the fan is installed that will determine the operating point on the fan curve. Thus it is vitally important that the system designer accurately determine the system losses in order to ensure that the actual air flow rate is as close as possible to the design air flow rate.

For additional information please refer to http://www.ventilating.com

Oleg Tchetchel
Industrial Process Engineer
NIS-CO Fan Co.

Total Views : 53Word Count Appx. : 550See All articles From Author

Technology, Gadget and Science Articles

1. Know The Ultimate Guide About How To Rent A Satellite Phone
Author: Dian Mark

2. Why Must Use Data Center?
Author: Luis Andrianto

3. Iphone 7 And 7 Plus: Seven Things To Know Before You Purchase
Author: randy

4. Factsebiz A Global Fully Incorporated Virtual Ecommerce Software Solution
Author: Facts HCM

5. Why Carbon Nanotubes Are Gaining More Popularity In The Nano Technology World?
Author: Ankush Sharma

6. Cctv Cameras Services And Solutions.
Author: yasir

7. Save Money With Jpi's Aircraft Fuel Flow Indicator
Author: Joseph Polizzotto

8. Power School - A New Way To Transform Communication With Schools As Well Parents
Author: Aaditya Aggrawal

9. Functional Testing In A Cloud Environment.
Author: Tom wade

10. Essential Tips For Boosting The Performance And Speed Of Windows 7
Author: David Semos

11. What Is The Re-certification Inspection?
Author: Jayden Joshua

12. Nano Lubricants Research: Opening Options For Progression And Growth
Author: mangesh shah

13. Importance Of Uat For Salesforce Testing
Author: Michael Wade

14. Portable Ip Cameras
Author: Edward Thompson

15. Top Reasons Why Businesses Should Move To Cloud Telephony
Author: Aaditya Aggrawal

Login To Account
Login Email:
Forgot Password?
New User?
Sign Up Newsletter
Email Address: