.AixLib.Obsolete.Year2024.DataBase.Chiller.PerformanceData.LookUpTable2D

Information

This model uses the 2-dimensional table data given in the DIN EN 14511 (formerly EN255) to calculate QEva and P_el. To model an inverter controlled chiller, the relative compressor speed n is scaled linearly with the ouput of the tables. Furthermore, the design of a chiller is modeled via a scaling factor. As a result, the equations follow below:

QEva,n = n * scalingFactor * TableQEva.y

P_el = n * scalingFactor * TablePel.y

To simulate possible icing of the evaporator on air-source chillers, the icing factor is used to influence the output as well. As the factor resembles the reduction of heat transfer between refrigerant and source, the factor is implemented as follows:

QEva = iceFac * QEva,n

With iceFac as a relative value between 0 and 1:

iceFac = kA/kA_noIce

Finally, to follow the first law of thermodynamics:

QCon = P_el,n + QEva

Known Limitations

The model CombiTable2DExtra is able to disallow extrapolation by holding the last value. If one extrapolates the given perfomance data, warnings about occuring extrapolations are emitted. CAUTION: Checking for possible extrapolations will trigger state events which results in higher computing time.

Revisions

• May 22, 2019  by Julian Matthes:
  First implementation (see issue #715)