.AixLib.Fluid.HeatPumps.ModularReversible.RefrigerantCycle.ConstantCarnotEffectiveness

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 AixLib library: AixLib.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

Revisions

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