modelComparePowerHydraulic

Compare power estimation with hydraulic power curve

Extends from Modelica.Icons.Example (Icon for runnable examples), Buildings.Fluid.Movers.Validation.BaseClasses.ComparePower (Base class for validation models that compare power estimation methods).

Information

The purpose of this validation is two-fold.

First, it validates that efficiency computation is implemented correctly for per.powerOrEfficiencyIsHydraulic=true. The results should show that η = ηhyd ηmot holds.

Second, it compares the power estimation results using different selections of per.etaHydMet.

  • The fan mov1 directly uses the power curve of the fan.
  • The fan mov2 uses the Euler number method to estimate the hydraulic efficiency and computer the power consumption.
  • The fan mov3 assumes a constant hydraulic efficiency to compute the power consumption.

The three methods agree with each other when the three fans operate at different speeds under constant system condition. Their power estimates diverge when the damper closes and the system curve is changed. The Euler number method was able to produce results close to the power curves and maintained positive power consumption as the flow rate approached zero. However, the constant efficiency assumption was not able to capture this characteristic.

Parameters

TypeNameDefaultDescription
Buildings.Fluid.Movers.Data.Genericper (from ComparePower)
Modelica.Units.SI.MassFlowRatem_flow_nominal (from ComparePower)per.peak.V_flow*rho_defaultNominal mass flow rate
Modelica.Units.SI.PressureDifferencedp_nominal (from ComparePower)per.peak.dpNominal pressure drop
Modelica.Units.SI.Densityrho_default (from ComparePower)Medium.density_pTX(p = Medium.p_default, T = Medium.T_default, X = Medium.X_default)Default medium density
Buildings.Fluid.Movers.BaseClasses.Euler.peakpeakBuildings.Fluid.Movers.BaseClasses.Euler.getPeak(pressure = per.pressure, power = per.power)Peak operating point

Components

TypeNameDefaultDescription
Buildings.Fluid.Movers.BaseClasses.PartialFlowMachinemov1 (from ComparePower)
Buildings.Fluid.Movers.BaseClasses.PartialFlowMachinemov2 (from ComparePower)
Buildings.Fluid.Movers.BaseClasses.PartialFlowMachinemov3 (from ComparePower)
Buildings.Fluid.Actuators.Dampers.ExponentialdamExp1 (from ComparePower)Damper
Buildings.Fluid.Actuators.Dampers.ExponentialdamExp2 (from ComparePower)Damper
Buildings.Fluid.Actuators.Dampers.ExponentialdamExp3 (from ComparePower)Damper
Buildings.Fluid.Sources.Boundary_pTsou (from ComparePower)Source
Buildings.Fluid.Sources.Boundary_pTsin (from ComparePower)Sink
Modelica.Blocks.Sources.RampramSpe (from ComparePower)Ramp signal for mover speed
Modelica.Blocks.Sources.RampramDam (from ComparePower)Ramp signal for damper position

Revisions

  • August 20, 2024, by Hongxiang Fu:
    Added standalone declaration for the peak operating condition to ensure that the same values are used for each mover. This is for IBPSA, #1912.
  • May 15, 2024, by Hongxiang Fu:
    First implementation. This is for IBPSA, #1880.