Technical data
14 | Project planning manual for heat pumps for heating and domestic hot water preparation | 01.2012 www.dimplex.de
1.3.2 Selection and design of heat pumps
1.3.2 Domestic hot water preparation
Domestic hot water consumption in buildings depends heavily on
usage. For normal comfort requirements, domestic hot water
consumption lies at between 80 and 100 litres per person, per
day, based on a domestic hot water temperature of 45 °C. In this
case, a heat output for domestic hot water preparation of 0.2 kW
per person must be taken into account.
NOTE
The maximum possible number of persons should be assumed when di-
mensioning, and any special usage (e.g. a spa bath) should also be taken
into consideration.
If the design point of the heat pump means that domestic hot
water preparation takes place via a flange heater, the additional
energy consumption for domestic hot water preparation does not
have to be added to the heating consumption.
Circulation pipes
Circulation pipes increase the line-side heat consumption of the
domestic hot water heating. This increase in consumption de-
pends on both the length of the circulation pipes and the quality
of the pipe insulation, and must be taken into consideration ac-
cordingly. If a circulation system cannot be dispensed with be-
cause of long pipe runs, a circulation pump should be used that
can be activated by a flow sensor according to need. The heat
consumption for a circulation pipe can be considerable.
NOTE
To be in compliance with Paragraph 12 (4) of the German Energy Effi-
ciency Ordinance, circulation pumps in domestic hot water systems must
be equipped with an automatic switch-on/switch-off mechanism.
1.3.3 Swimming pool water heating
Outdoor swimming pool
The heat consumption for heating the water in an outdoor swim-
ming pool depends strongly on the respective usage.
In terms of size, it can easily be the same as the heat consump-
tion of a house - and in such cases must be calculated sepa-
rately.
However, if heating is only carried out in the summertime (period
not requiring heating), the heat consumption can be ignored in
certain cases.
An approximate estimation of the heat consumption is dependent
on the windage factor, the temperature of the pool, the climatic
conditions, the periods of use and whether or not the pool has a
cover.
Table 1.5: Reference values for the heat consumption of outdoor swimming
pools used between May and September
For initially heating the pool to a temperature of over 20 °C, the
quantity of thermal energy required is approx. 12 kWh/m
3
pool
volume. Heating-up periods ranging from one to three days are
required depending on the size of the pool and the output of the
installed heating system.
Indoor swimming pool
Space heating
Space heating is generally carried out using radiators or un-
derfloor heating and/or a heating register in the dehumidifi-
cation/ventilation system. In both cases, it is necessary to
calculate the heat consumption - according to the system in-
stalled.
Swimming pool water heating
The heat consumption depends on the pool temperature,
the temperature difference between the pool temperature
and the room temperature, and the pool usage.
Table 1.6: Reference values for the heat consumption of indoor swimming
pools
These outputs can be reduced by up to 50% for private swim-
ming pools with a cover that are used for a maximum of 2 hours
per day.
NOTE
When using a brine-to-water heat pump for swimming pools, the heat
source must be designed for the higher number of hours per year that the
heat pump is operated to its full potential.
Water temperature
20 °C 24 °C 28 °C
With cover
1
1. Reduced values for pools with a cover only refer to private swimming pools
used on average up to 2 hrs per day.
100 W/m
2
150 W/m
2
200 W/m
2
without cover
sheltered location
200 W/m
2
400 W/m
2
600 W/m
2
without cover
partially sheltered
location
300 W/m
2
500 W/m
2
700 W/m
2
without cover
unsheltered location
(subject to high winds)
450 W/m
2
800 W/m
2
1,000 W/m
2
Room
temperature
Water temperature
20 °C 24 °C 28 °C
23 °C
90 W/m
2
165 W/m
2
265 W/m
2
25 °C
65 W/m
2
140 W/m
2
240 W/m
2
28 °C
20 W/m
2
100 W/m
2
195 W/m
2