C Node 1 represents the condenser heat exchanger and couples to the hydronic
C heating circuit. The device has an internal pump and so an explicit pump
C model is not needed in system models containing this component.
C
C Four "COP" models are available.
C
C Model 1, "simple", is basically for testing. With this mode, the icGSHP
C can be used with very limited input data as follows.
C   HP_0(1)     0 % heating power for nominal SH temperature (kW)
C   HP_0(2)   100 % heating power for nominal SH temperature (kW)
C   HP_0(3)     0 % cooling power for nominal SH temperature (kW)
C   HP_0(4)   100 % cooling power for nominal SH temperature (kW)
C   HP_0(5)     0 % heating power for nominal DHW temperature (kW)
C   HP_0(6)   100 % heating power for nominal DHW temperature (kW)
C   HP_100(1)   0 % cooling power for nominal DHW temperature (kW)
C   HP_100(2) 100 % cooling power for nominal DHW temperature (kW)
C Note that both inverter control modes can be used with this simplified model,
C however, source temperature dependency is ignored and thus the HP only
C very crudely approximated.
C
C Model 2, is not available, currently!
C
C Model 3 + 4, spline and polynomial interpolations of power output
C respectively. These modes expect a data file <<componentname>>.hpd
C in the same subdirectory as the .pln file itself.
C The data file must contain following data in the given structure:
C performance data file, containing a header line and three columns of
C data. NX and NY are the number of data points for tgrnd and tfeed,
C respectively.
C
C Format:
C NX, NY
C Tgrnd1,  Tfeed1,  HPheat0-1, HPheat100-1, HPcool0-1, HPcool100-1
C Tgrnd1,  Tfeed2,  HPheat0-2, HPheat100-2, HPcool0-2, HPcool100-2
C ...
C Tgrnd1,  TfeedNY, HPheat0-N, HPheat100-N, HPcool0-N, HPcool100-N
C Tgrnd2,  Tfeed1,  HPheat0-1, HPheat100-1, HPcool0-1, HPcool100-1
C ...
C ...
C TgrndNX, TfeedNY, HPheat0-N, HPheat100-N, HPcool0-N, HPcool100-N
C
C The R-script ../doc/plot_icGSHP_Perfdata.r can be used as basis for the 
C generation of the appropriate data file (currently generates data for a
C "cta Optiheat Inverta Economy Compact OH I 9ec".
C
C This particular device model is suitable for ON/OFF type control in control
C mode 1 and PI-type control in control mode 2. The model internally
C controls the compressor frequency in mode 1. Ambient temperature compensation
C for the space heating return temperature can be applied [linear model].
C
C Control parameter number three (3) is the "preference signal":
C   0 space heat, 1 DHW high, 2 DHW low
C
