Technical data

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Domestic hot water preparation with heat pumps 6.5.5
6.5.2 Cylinder with electric immersion heater (off-peak electricity)
Advantages in comparison to heat pumps for
heating purposes:
a) Smaller investment
b) Higher domestic hot water temperatures possible in the cyl-
inder (but often not required!)
c) Increased heat pump availability for space heating
(particularly in the case of monovalent operation and during
shut-off times).
Disadvantages in comparison to heat pumps for
heating purposes:
a) Higher operating costs
b) Only limited availability
c) Increased lime scaling possible
d) Longer heating-up periods
6.5.3 Domestic hot water heat pumps
Advantages in comparison to heat pumps for
heating purposes:
a) A cooling or dehumidification effect can be produced at the
installation location (e.g. storage cellar) in the summertime
b) Increased heat pump availability for space heating (particu-
larly in the case of monovalent operation and during shut-off
times)
c) Easy integration of solar thermal systems
d) Higher domestic hot water temperatures when only the heat
pump is in operation
Disadvantages in comparison to heat pumps for
heating purposes:
a) Considerably longer domestic hot water cylinder reheating
times
b) Heat output is normally insufficient if the domestic hot water
consumption is high
c) The installation room could become cold in the wintertime
6.5.4 Domestic ventilation unit with domestic hot water preparation
Advantages in comparison to heat pumps for
heating purposes:
a) Comfortable domestic ventilation to ensure hygienic air cir-
culation
b) Domestic hot water preparation using active year-round
heat recovery from exhaust air
c) Increased heat pump availability for space heating
(particularly in the case of monovalent operation and during
shut-off times)
d) Easy integration of solar thermal systems
e) Higher domestic hot water temperatures when only the heat
pump is in operation
Disadvantages in comparison to heat pumps for
heating purposes:
a) Considerably longer domestic hot water cylinder reheating
times with heat pump operation
b) Combination with a second heat generator is essential if the
domestic hot water consumption is high
6.5.5 Summary
Heating domestic hot water with a heat pump is practical and
economical on account of the good performance factor.
Domestic hot water for normal usage should be prepared using a
domestic ventilation unit if living space ventilation is necessary or
desired. The integrated air-to-water heat pump extracts the
stored energy in the exhaust air and utilises it for year-round do-
mestic hot water preparation.
Electric domestic hot water appliances can also be appropriate
depending on the tariff structure of the local utility company, the
domestic hot water consumption, the required temperature level
and the location of the extraction points.