modelConstantCarnotEffectiveness

Carnot COP with a constant Carnot effectiveness

Extends from BuildingSystems.Fluid.HeatPumps.ModularReversible.RefrigerantCycle.BaseClasses.PartialHeatPumpCycle, BuildingSystems.Fluid.HeatPumps.ModularReversible.RefrigerantCycle.BaseClasses.PartialCarnot.

Information

This model uses a constant Carnot effectiveness to compute the efficiency of the heat pump.

PEle_nominal is computed from the provided QHea_flow_nominal and other nominal conditions. PEle_nominal stays constant over all boundary conditions and is used to calculate PEle by multiplying it with the relative compressor speed. QCon_flow is computed using the Carnot approach:

QCon_flow = PEle_nominal * etaCarnot_nominal * yMea * (TConOut + TAppCon) / (TConOut + TAppCon - (TEvaOut - TAppEva))

PEle = PEle_nominal * yMea

This equations follows the Carnot approach of the BuildingSystems library: BuildingSystems.Fluid.HeatPumps.Carnot_y Similarly, the variables TAppCon and TAppEva define the approach (pinch) temperature differences.

The approach temperatures are calculated using the following equation:

TApp = TApp_nominal * Q_flow / Q_flow_nominal

This introduces nonlinear equations to the model, which can lead to solver issues for reversible operation. You can fix the approach temperature at the nominal value by setting use_constAppTem

Parameters

TypeNameDefaultDescription
RealCOP_nominaletaCarnot_nominal*(TCon_nominal + TAppCon_nominal)/(TCon_nominal + TAppCon_nominal - (TEva_nominal - TAppEva_nominal))Nominal coefficient of performance

Revisions

  • October 2, 2022 by Fabian Wuellhorst:
    First implementation (see issue #1576)