Rotex HPSU compact 304, Instruction Manual

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2 x Product description
BA ROTEX HPSU compact 4 - 09/2013
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2 Product description
2.1 Brief description
The air-water heat pump system uses the physical effect of heat
from condensation and makes it possible, as required, to heat or
cool buildings. The Solar tank with integrated interior heat pump
unit (ROTEX HPSU compact) is the central component of the
high-efficiency heating and cooling system for the residential
area.
The external heat pump unit (RRLQ) comprises the refrigerant
compressor and the capacitor (this works during cooling) or va-
poriser (this works during heating), which capture the ambient air
temperature. The external heat pump unit (RRLQ) is connected
to the internal heat pump unit (HPSU compact) in the building
with a closed refrigerant circuit. Heat or cold are transported be-
tween the external heat pump unit (RRLQ) and the internal heat
pump unit (HPSU compact) by the circulating refrigerant, which
alternately assumes the aggregate states of liquid and gas.
The internal heat pump unit (HPSU compact) contains the control
devices, the heat exchanger and integrated storage tank. In the
heat exchanger, the heat is transferred to the water flowing in the
heating circuit or the water in the storage tank (heating/warm
water supply), or heat is extracted from the water (cooling).
The storage tank on the ROTEX HPSU compact is built in such a
way to enable the heat pump system to be combined with a
ROTEX solar system without needing an additional hot water
tank.
With the optional ancillary heating, depending on the heat

delivery from the sun, the entire hot water storage tank can be
heated up via the spiral corrosion-resistant heat exchanger,
mounted entirely within the tank, and made of corrugated
stainless steel tubing (1.4404). The stored heat is used both for
hot water heating and for heating support. The high total storage
capacity also temporarily allows time without sunshine to be
bridged. The excellent heat insulation properties of the integrated
storage tank also ensure that heat losses are kept to a minimum.
This allows efficient and economical hot water heating and
heating support.
If the heating capacity of the HPSU compact is not adequate, the
optional backup heater (BUH) can provide additional heating

capacity for heating the heating circuit. As a result of the special
storage tank design and intelligent regulation technology, in the
HPSU compact we can also use the backup heater (BUH) for
auxiliary heating of the preparation zone (hot water) (booster
heater function).
Instead of the ancillary electrical heating, you can also connect
the ROTEX G-plus instantaneous gas heater to the HPSU
compact.
To enable even more efficient use of the ROTEX HPSU compact,
it is also possible to operate it with an off-peak mains connection.
Information on the prerequisites and connection possibilities are
described in the enclosed installation manual.
2.1.1 Mode of operation
In room heating operation the refrigerant compressed by the

refrigerant compressor in the external heat pump unit (RRLQ)
condenses in the underfloor heating heatexchanger of the interior
heat pump unit (HPSU compact). The underfloor heat exchanger
is fed with colder stored water in its interior, which takes up the
heat released by the condensing coolant. The circulation pump
provides a permanent flow of the water in the internal tank circuit.
The readiness zone of the storage tank integrated into the interior
heat pump unit (HPSU compact) is heated by the heat pump or
other external heat generators (solar system, backup heater).
The cold water flowing downstream of the warm water extraction
cools the lower area of the integrated storage tank to maximum
effect.
The drinking water is heated indirectly in a corrosion resistant
stainless steel corrugated pipe heat exchanger by the unpres-
surised water from the integrated storage tank. On its way to the
top, it continuously absorbs the heat from the storage tank water.
The flow direction, operating on the principle of counter-flow, and
the coil-shaped heat exchanger create a pronounced temper-
ature layering in the hot water storage tank. As high temperatures
can be maintained for a very long time in the upper section of the
storage tank, a high hot water output is achieved even if water is
drawn off over a long period of time.
In room cooling the 3-way switching valves (3UV1 + 3UVB)
mounted on the heat pump internal unit (HPSU compact)
switches off the flow to storage tank charging/heating support.
The circulation pump of the internal heat pump device (HPSU
compact) now directly affects the heating circuit. The coolant
condenser built into the exterior heat pump unit (RRLQ) reverses
the effects of the coolant circuit. The water in the heating system
is pumped through the circulation pump in the interior heat pump
unit (HPSU compact) and is cooled down there.
The heating/cooling output that can be used on the liq-
uefier (interior heat pump unit), in relation to the elec-
trical power of the refrigerant compressor (external heat
pump unit), increases as the difference between the va-
porisation and liquefaction temperature in the refrig-
erant circuit decreases.
A low heat carrier temperature (flow temperature) can
be attained in particular with the underfloor heating
system, as the heat transfer area is extremely large.
Furthermore, the building to be heated should ideally
have extremely good heat insulation, so that when
there is a low heat requirement, the heat carrier can run
with a low flow temperature.