In general: SPF = benefit / effort
Seasonal Performance Factor of the heat pump
Determined by Simulation, with test points: Benefit is the heat supplied by the heat pump, and effort is the power consumption of the heat pump without external pumps and without a heating element.
Seasonal Performance Factor of the heat pump system:
Benefit is the heat supplied by the heat pump and the heating element in total.
Effort = power consumption of the heat pump
+ heating element energy consumption
+ power consumption of external pumps on the heat source side of the heat pump.
Seasonal Performance Factor of the generator system (HP + solar):
The benefit is the total heat supplied by the heat pump, heating element, and solar system.
Effort = power consumption of the heat pump
+ heating element energy consumption
+ power consumption of external pumps on the heat source side of the heat pump
+ power consumption of the solar circuit pump.
Full load hours
Shows the number of hours in which the heat
pump operates at maximum output. A very low value is an indication
that the heat pump is oversized.
Number of hours with more than one Switch-on process:
Indicates the number of hours in which the heat pump is switched on more than once per hour.
Number of hours with more than four Switch-on processes:
Indicates the number of hours in which
the heat pump is switched on more than four times per hour. A very high value is an indication
that the heat pump is oversized.
The heat pump has a minimum output at which it must be operated in order to remain switched on.
If the output falls below this value, the heat pump switches itself off again. This means that if the required
output is too low, the heat pump switches itself on and off again several times in succession.
These switch-on and switch-off processes affect the service life of the heat pump.
Therefore it is important not to oversize the heat pump.
For mono-energetic systems, the power fraction at standard outdoor temperature must be entered to calculate the coverage fraction. The power share at standard outside temperature can be determined from the manufacturer’s data for the heat pump.
The following values are determined from the simulation results:
Min. source temperature (not applicable for air/water heat pumps)
Coverage fraction (calculated only for mono-energetic systems, taking into account the power fraction at standard outdoor temperature).
Outside temperature at the shutdown point (will be displayed from the page Operating mode in partially parallel operating mode adopted)
SPF heat pump (calculated seasonal performance factor according to VDI 4650)
SPF heat pump incl. solar system (calculated seasonal performance factor according to VDI 4650, taking into account the solar system)