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Thanks to innovative inverter technology, this
heat pump will almost always operate by
adapting its heat output to the actual require-
ments of the heating season, and will in fact
turn itself off when heat is no longer needed.
The same applies in the opposite direction with
cooling.
Defrost by circulation reversal
At temperatures below about +5°C, humidity
freezes in the evaporator (outdoor module) and an
ice layer can form which reduces heat transfer
from the air to the refrigerant and to the air stream.
This layer of ice must be removed. A four-way
valve serves to reverse the refrigerant circuit, so
that the hot gas from the compressor flows through
the original evaporator and the ice that has formed
there can melt. The defrost process is not initiated
after a predetermined time; rather it is carried out
as required in order to save energy.
Cooling mode
Because of circuit reversal, cooling is also pos-
sible. In cooling mode, the components of the
refrigeration circuit are used to produce cold water
with which heat can be extracted from a building.
This can be accomplished with dynamic cooling or
passive cooling.
uncomfortably
dry
10
12
Fig. 20: Comfort zone
comfortable
still comfortable
14
16
18
20
Under dynamic cooling the refrigerating capacity
is actively transferred to the indoor air. This is
undertaken by means of water-based fan convec-
tors. In doing so, it is desirable that the inlet tem-
peratures are under the dewpoint, in order to
transfer a higher refrigerating capacity and to
dehumidify the indoor air.
Passive cooling refers to the absorption of heat
via cooled floors, walls or ceiling surfaces. In doing
so, water-carrying pipes make the structural sec-
tions into thermically effective heat exchangers. In
order to achieve this, the refrigerant temperature
has to lie above the dew point, in order to avoid the
formation of condensation. Dewpoint monitoring is
required for this purpose.
We recommend dynamic cooling with fan convec-
tors, in order to achieve increased thermal per-
formance and in order to dehumidify the air on
muggy summer days. The advantage here is that
dewpoint monitoring is not required.
The comfort zone in the illustration below shows
which values for temperature and humidity are
considered comfortable for people. This range
should ideally be met when heating or air-condi-
tioning buildings.
uncomfortably
humid
22
24
26
Room air temperature in °C
28
30
23
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