Installation manual
www.dimplex.de 15
Selection and Design of Heat Pumps 1.3.4.4
35 °C. The intersection points (limit temperature or bivalence
point) of the straight line of the heat consumption of the building
in relation to the outside temperature and the heat output curves
of the heat pumps are approx. -5.0 °C for HP 1 and approx. -9 °C
for HP 2. HP 1 would be used for the selected example. A
supplementary electric heating system is used to enable year-
round heating. This compensates for the difference between the
heat consumption of the building in relation to the outside
temperature and the heat output of the heat pump for the
corresponding air intake temperature.
Design of the supplementary electric heating
system:
For example:
HP 1 should be dimensioned with a heating element that has an
electrical output of 6.0 kW for the selected example.
1.3.4.3 Water-to-water and brine-to-water heat pumps (monovalent operation)
NOTE
Refer to the operating instructions of the respective device for the actual
heat outputs of water-to-water and brine-to-water heat pumps at each
respective flow temperature.
For example:
Fig. 1.5 on p. 15 shows the heat output curves of brine-to-water
heat pumps. The heat pump to be selected is the one having a
heat output which is above the intersection of the required total
heat consumption and the temperature of the available heat
source.
Fig. 1.5: Heat output curves of brine-to-water heat pumps with different heat
outputs for flow temperatures of 35 °C.
The output curve of HP 5 must be selected for a maximum
required flow temperature of 35 °C for a total heat consumption
of 13.8 kW and a minimum brine temperature of 0 °C. This yields
a heat output of 14.5 kW for the above boundary conditions.
1.3.4.4 Water-to-water and brine-to-water heat pumps (mono energy operation)
Mono energy brine-to-water or water-to-water heat pump
systems are equipped with a second electrically operated heat
generator, e.g. a buffer tank with an electric heating element.
Mono energy brine-to-water or water-to-water heat pump
systems should only be planned in exceptional circumstances if
shut-off times mean that large quantities of power must be drawn
from the grid or if, on account of the available device range, a
heat pump must be selected which has a considerably larger
output in comparison to the total heat consumption. Mono energy
operation is also particularly suitable for the first heating period if
the building is dried out in autumn or in the winter.
Total heat consumption on the coldest day
– Heat output of the heat pump on the coldest day
= Output of the heating elements
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Total calculated heat consumption = _____kW
= Heat output of the heat pump
for W10 /W35
1
or BO/W35
1
1. For monovalent systems, dimensioning should be based on both the
maximum flow temperature and the minimum heat source temperature!
Monovalent operation for a heating system
with a maximum flow temperature of 35 °C.
Selected heat consumption of the house to be
heated
10.6 kW
Heat consumption of the house and
components x factor f from Table 1.2 on p. 12
(for e.g. a 6 h shut off time; f = 1.3) = fictitious
total heat consumption.
Total heat consumption= 10.6 kW x 1.3 = 13.8 kW
= Heat output of the heat pump
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