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values were measured according to test standards EN 255 or EN 14511 on predefined sampling
points (e.g. A2/W35). The electrical power absorbed by the heat-pump is calculated by linear
interpolation of the sampling points. The thermal heating power is defined by linear interpolation
of the corresponding quality grade of the sampling points.
Frosting and de-frosting behaviour are likewise taken into account through the norm and may be
thus simulated in Polysun. This model only applies to intermittent heat pumps; variable-speed heat
pumps are described in the chapter 5.5.3 “Modulating air-to-water heat pump”.
The results “Energy from/to system“ and “End Energy“ include the power of the heat pump and
that of the internal heating element, in case the auxiliary heating was switched on. To calculate the
COP (Coefficient of Performance), the power of the internal heating element is, however, to be
deducted from the results. The result “COP“, therefore, only applies to the compressor and not to
the heating pump as a whole.
The absorbed power of compressor, internal circulation pump, fan as well as the supplied heat
output are taken into account in the COP calculation.
Within a hydraulic scheme you will be able to switch from a boiler to a heat-pump by accordingly
setting the selection of the heat generator.
Figure 19: selection of air-to-water heat pump
The heat-pump-specific operating times may be defined by means of the minimum operation times
and minimum idle period that may found in the heating controller.
Q is implemented from the measured values; this requires Tv. This is approximated through TU =
Q’/k * V – Ti (1) where k = Qref / Vref * 1/DeltaTref (2) and Q’ from the previous time-step or on
switching on the heat-pump Q’ = Qref. This allows Polysun to calculate with Q’, V, Ti the outflow
temperature.
All calculations are carried out with delta Tref.
As a result: the calculation enables a correct calculation also for arbitrarily selected v.
Exceptions: for (1) and (2): the internal heat-exchanger is capable of transferring the overall power.
The formulism will become inaccurate for V << Vref.
5.4.8.1
Catalogue entries with reference points from a file
The file format for the definition of reference points in a profile file is as follows:
User Manual Polysun
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