.BuildingSystems.Fluid.Chillers.ModularReversible.RefrigerantCycle.TableData2D

Information

This model uses two-dimensional table data typically given by manufacturers as required by e.g. European Norm 14511 or ASHRAE 205 to calculate QEva_flow and PEle.

For different condenser outlet and evaporator inlet temperatures, the tables must provide two of the three following values: electrical power consumption, evaporator heat flow rate, and COP.

Note that losses are often implicitly included in measured data. In this case, the frosting modules should be disabled.

Scaling factor

For the scaling factor, the table data for evaporator heat flow rate (QEvaTabDat_flow) is evaluated at nominal conditions. Hence, the scaling factor is

scaFac = QEva_flow_nominal/QEvaTabDat_flow(TEva_nominal, TCon_nominal).

Using scaFac, the table data is scaled linearly. This implies a constant COP over different design sizes:

QEva_flow = scaFac * tabQEva_flow.y

PEle = scaFac * tabPel.y

Known Limitations

• Manufacturers are not required to provide the compressor speed at which the data are measured. Thus, nominal values may be obtained at different compressor speeds and, thus, efficiencies. To accurately model the available thermal output, please check that you use tables of the maximal thermal output, which is often provided in the data sheets from the manufacturers. This limitation only holds for inverter driven chillers.
• We assume that the efficiency is contant over the whole compressor speed range. Typically, efficiencies will drop at minimal and maximal compressor speeds. To model an inverter controlled chiller, the relative compressor speed yMea is used to scale the ouput of the tables linearly. For models including the compressor speed, check the SDF-Library dependent refrigerant cycle models in the AixLib Library.

References

EN 14511-2018: Air conditioners, liquid chilling packages and heat pumps for space heating and cooling and process chillers, with electrically driven compressors https://www.beuth.de/de/norm/din-en-14511-1/298537524

Revisions

• October 2, 2022 by Fabian Wuellhorst:
  Adjusted based on the discussion in this issue #1576)
• May 22, 2019, by Julian Matthes:
  First implementation (see issue AixLib #715)