21
legend
1
Stage 1
2
Stage 2
3
Stage 3
4
Stage 4
A Heat pump capacity variation as a function of the air temperature
B Building thermal load
C Balance point between the capacity supplied by the heat pump and the thermal load of the building
Operating range, in which the heat pump capacity is lower than the building thermal load
Operating range, in which the heat pump capacity is higher than the building thermal load
Outdoor air temperature, °C
Pump capacity (%)
Example of additional electric heaters
1
A
2
3
4
B
120
100
80
60
40
20
0
-15
-10
-5
0
5
10
15
1
1
2
C
