.BuildingSystems.Fluid.Movers.Examples.StaticReset

Information

This example model compares the three power computation methods in a scenario where the fan performance (P vs. V̇) is examined to verify savings of a static pressure reset. The fan speed is controlled to track the duct static pressure at a point downstream while the damper (representing a VAV box) moves from fully closed to fully open. The system was described in Englander and Norford (1992). The fan data are implemented in BuildingSystems.Fluid.Movers.Examples.Data.EnglanderNorford1992.

• The first fan uses the fan curve to estimate the shaft power at reduced speed.
• The second fan uses the Euler number and its correlation to estimate the hydraulic efficiency.
• The third fan assumes a constant hydraulic efficiency.

In the results, P computed from the Euler number and from the power curve agree on the trend of P vs. V̇. Both of them are also able to prevent P from incorrectly going to zero as V̇ approaches zero, which the method with constant efficiency failed.

References

Englander, S. L., and L. K. Norford. "Saving fan energy in VAV systems- part 1: analysis of a variable-speed-drive retrofit." ASHRAE Winter Meeting, Anaheim, CA, USA, 01/25-29/92. 1992.

Contents

Revisions

• January 24, 2022, by Hongxiang Fu and David Blum:
  First implementation. This is for #2668.