5 Application guidelines
Installer reference guide
18
RRLQ004~008CA + RHBH/X04+08CB
ROTEX HPSU low temperature Bi‑bloc
4P384979-1 – 2015.01
▪ The higher the outdoor temperature, the better the performance of
the heat pump.
▪ If energy prices are the same during the day and the night,
ROTEX recommends to heat up the DHW tank during the day.
▪ If energy prices are lower during the night, ROTEX
recommends to heat up the DHW tank during the night.
▪ When the heat pump produces domestic hot water, it cannot heat
up a space. When you need domestic hot water and space
heating at the same, ROTEX recommends to produce the
domestic hot water during the night when there is lower space
heating demand.
Determining the DHW consumption
Answer the following questions and calculate the DHW consumption
(equivalent hot water volume at 40°C) using the typical water
volumes:
Question
Typical water volume
How many showers are needed
per day?
1 shower = 10 min×10 l/min =
100 l
How many baths are needed per
day?
1 bath = 150 l
How much water is needed at the
kitchen sink per day?
1 sink = 2 min×5 l/min = 10 l
Are there any other domestic hot
water needs?
—
Example: If the DHW consumption of a family (4 persons) per day is
as follows:
▪ 3 showers
▪ 1 bath
▪ 3 sink volumes
Then the DHW consumption = (3×100 l)+(1×150 l)+(3×10 l)=480 l
Determining the volume and desired temperature for the DHW
tank
Formula
Example
V
1
=V
2
+V
2
×(T
2
−40)/(40−T
1
)
If:
▪ V
2
=180 l
▪ T
2
=54°C
▪ T
1
=15°C
Then V
1
=280 l
V
2
=V
1
×(40−T
1
)/(T
2
−T
1
)
If:
▪ V
1
=480 l
▪ T
2
=54°C
▪ T
1
=15°C
Then V
2
=307 l
V
1
DHW consumption (equivalent hot water volume at 40°C)
V
2
Required DHW tank volume if only heated once
T
2
DHW tank temperature
T
1
Cold water temperature
5.4.4
Setup and configuration – DHW tank
▪ For large DHW consumptions, you can heat up the DHW tank
several times during the day.
▪ To heat up the DHW tank to the desired DHW tank temperature,
you can use the following energy sources:
▪ Thermodynamic cycle of the heat pump
▪ Electrical backup heater (for integrated DHW tank)
▪ Electrical booster heater (for standalone DHW tank)
▪ For more information about:
▪ Optimizing the energy consumption for producing domestic hot
water, see
.
▪ Connecting the electrical wiring of the standalone DHW tank to
the indoor unit, see the installation manual of the DHW tank.
▪ Connecting the water piping of the standalone DHW tank to the
indoor unit, see the installation manual of the DHW tank.
5.4.5
DHW pump for instant hot water
Setup
c
f
a
b
g
h
i
a
Indoor unit
b
DHW tank
c
DHW pump (field supply)
f
Shower (field supply)
g
Cold water
h
Domestic hot water OUT
i
Recirculation connection
▪ By connecting a DHW pump, instant hot water can be available at
the tap.
▪ The DHW pump and the installation are field supply and the
responsibility of the installer.
▪ For more information about connecting the recirculation
connection:
▪ for integrated DHW tank, see
▪ for separate DHW tank, see installation manual of DHW tank.
Configuration
.
▪ You can program a schedule to control the DHW pump via the
user interface. For more information, see the user reference
guide.
5.4.6
DHW pump for disinfection
Setup
c
a
b
d f
e g
h
i
a
Indoor unit
b
DHW tank
c
DHW pump (field supply)
d
Heater element (field supply)
e
Non‑return valve (field supply)
f
Shower (field supply)
g
Cold water
h
Domestic hot water OUT
i
Recirculation connection
▪ The DHW pump is field-supplied and its installation is the
responsibility of the installer.
▪ For the integrated DHW tank, the temperature of the DHW tank
can be set to maximum 60°C. If applicable legislation requires
higher temperature for disinfection, you can connect a DHW pump
and heater element as shown above.
▪ If applicable legislation requires disinfection of the water piping
until the tapping point, you can connect a DHW pump and heater
element (if needed) as shown above.
Configuration
The indoor unit can control DHW pump operation. For more
information, see
