REMKO CMF-120-1P - Manual (Page 10)

REMKO CMF / CMT
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
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-conditioning buildings.
Because of circuit reversal, cooling is
also possible.
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.
Under dynamic cooling the
refrigerating capacity is actively
transferred to the indoor air. This is
undertaken by means of water-based
fan convectors. In doing so, it is
desirable that the inlet temperatures
are under the dewpoint, in order to
transfer a higher refrigerating capacity
and to dehumidify the indoor air.
10 12 14 16 18 20 22 24 26 28 30
100
90
80
70
60
50
40
30
20
10
0
uncomfortably
humid
uncomfortably
dry
comfortable
still comfortable
Room air temperature in o C
Relative humidity in %
Passive cooling refers to the
absorption of heat via cooled floors,
walls or ceiling surfaces. In doing
so, water-carrying pipes make the
structural sections 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 convectors, in order to achieve
increased thermal performance and in
order to dehumidify the air on muggy
summer days. The advantage here
is that dewpoint monitoring is not
required.
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