System limits

System limits Heat pump data is taken from tests according to EN14511, therefore the head losses from heat source fans or liquid pumps are taken into account in the heat capacity and COP data. This model also includes the heat sink liquid pump.
The model takes into account the net space heating demand, Lh, of the house. The heat demand of the house is a consequence of the choice of the load profile and the so-called system losses Lsys. The size of Lsys depends on the characteristics of the boiler and the installation characteristics. The system losses include fluctuation losses, stratification losses, distribution losses, buffer losses and timer losses, which are set as a percentage that is depending on the heat demand.  
The model also includes losses from control, auxiliary equipment and system buffer standing losses.  
A back up heater is used to cover up the energy demand that the heat pump cannot deliver.  
The electricity use in the model is accounted with the primary energy factor 2.5