It can also be used to project pump and fan performance characteristics based on a known characteristic when used in combination with other affinity laws. For example, if you have a known impeller line on a pump curve, you can use the "Square Law" and the affinity law relating impeller diameter and flow to project what the impeller line would look like for a different impeller size.
You will find a detailed discussion of the square law and some related resources under the "Useful Resources" page of the web site. The spreadsheet tool provided here allows you to enter a known operating point and then projects the system curve for that operating point for a number of arbitrarily selected flow conditions. You also have the option of adjusting the exponent to reflect the values recommended by ASHRAE for systems that do no operate with fully developed turbulent flow at all locations and to adjust for the lift in an open system and a fixed differential pressure operating point in a closed system.
You can also insert this spreadsheet as a new tab in a pump curve spreadsheet like the template we provided as an example of using Plot Digitizer and plot the system curve it generates on your pump curve.
You can also insert this spreadsheet as a new tab in a pump curve spreadsheet like the template we provided as an example of using Plot Digitizer and plot the system curve it generates on your pump curve.
system_curve_vweb.xlsx |