OPERATING AND INSTALLATION MANUAL HEAT PUMP COMBI UNIT PKOM4 PAGE 31
USER
GENERALSPECIALIST PERSONNEL
14. System description and extension options
The heat pump combi unit will already
provide a passive house with a large part
of its required heating and cooling power.
Supplementary heating may be necessary
during lengthy periods of negative outside
temperatures.
The heat pump combi unit PKOM
4
classic
unites the four functions of ventilation,
heating, cooling, and hot water produc-
tion on an installation space of less than
0.75m². The controlled housing ventilation
permanently supplies the rooms with
fresh and filtered air from the outside and
ensures the hygienic exchange of air. The
highly ecient heat recovery system is
also optionally available as a design with
recovery of waste air humidity. To prevent
overly high summer temperatures in the
living rooms, heat recovery may also be
bypassed during cooler night hours by
means of a bypass flap.
A controlled heat pump will in addition
condition the supply air, i.e. heated or
cooled on demand. Another heat pump is
used for ecient provision of household
hot water. Both heat pumps may be oper-
ated in parallel to ensure uninterrupted
provision of air and water. An elaborate
system provides for the provision of far
more air via the evaporator in parallel
operation, thus providing sucient perfor-
mance to both heat pump circuits.
Advantage of the two heat pump circuits
The heat pump module consists of two
separate heat pump circuits. One circuit
heats or cools the supply air, the other
circuit heats the hot water in the tank.
The special characteristic is that the heat
exchanger (see Section 14.1.1, item 10
in the graphics) has been designed as a
two-circuit heat exchanger. This means
that both heat pump circuits use the same
heat exchanger, the duct rows of the heat
exchanger, however, are distributed to
two circuits. If only one heat pump circuit
is running, therefore the double heat
exchanging surface is provided. If both
heat pump circuits are running, the air
throughput through the heat exchanger
is increased so that both circuits receive
sucient performance. This technology
makes it possible to heat up the supply air
and the hot water at the same time.
In simple heating or cooling operation the
air flap (see Section 14.1.1, item 9 in the
graphics) between the outdoor air and
the exhaust air remains shut and the fans
exactly convey the air volume flow which is
required for attaining the heating or cool-
ing performance. In heating operation the
heat exchanger in the exhaust air (see Sec-
tion 14.1.1, item 10 in the graphics) serves
as an evaporator of the heat pump circuit
and extracts energy from the exhaust air.
Via the heat exchanger (see Section14.1.1,
item 12 in the graphics) in the supply air,
heating energy is fed to the supply air. In
cooling operation the heat pump circuit is
reversed and the supply air is cooled while
the exhaust air is heated.
If, during heating operation, the second
heat pump is now also required for heating
the hot water, the air flap will open (see
Section 14.1.1, item 9 in the graphics), the air
flow of the outdoor air being divided. One
part is still guided through the heat recov-
ery unit and flows into the living spaces as
supply air, the other part flows directly into
the exhaust air section and mixes with the
air extracted from the extract air sections.
In this mode, the external fan is actuated at
a higher speed and the air flow is substan-
tially increased. The air volume flow into
the supply air sections remains constant,
the air flow via the heat exchanger (see
Section 14.1.1, item 9 in the graphics) in the
exhaust air, however, now has sucient
performance to supply both heat pump
circuits. The air valves (see Section 14.1.1,
item 9 in the graphics) and (see Section
14.1.1, item 11 in the graphics) are continu-
ously regulated so as to ensure the desired
supply air volume.
14.1 FUNCTIONAL DIAGRAMS
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