System overview 3
0020196687_03 flexoTHERM exclusive Installation and maintenance instructions
9
in the evaporator must have a lower temperature than the
heat source. On the other hand, the temperature of the refri-
gerant in the condenser must be higher than that of the heat-
ing water in order to be able to release the thermal energy to
it.
These different temperatures are produced in the refrigerant
circuit by means of a compressor and an expansion valve,
which are located between the evaporator and condenser.
The refrigerant flows in vapour form from the evaporator into
the compressor, where it is compressed. This causes the
pressure and temperature of the refrigerant vapour to rise
sharply. After this process, it flows through the condenser,
where it releases its thermal energy to the heating water by
condensation. It flows as a liquid into the expansion valve,
where it expands significantly and, in so doing, loses much
of its pressure and temperature. This temperature is now
lower than that of the brine that flows through the evaporator.
The refrigerant can thus absorb more thermal energy in the
evaporator, turning into vapour in the process and flowing to
the compressor. The cycle starts again.
The evaporator and parts of the refrigerant circuit inside the
heat pump are cold-insulated, meaning that no condensate
can accumulate. Any small amounts of condensate which
may form evaporate as a result of the heat generated inside
the heat pump.
The product is equipped with an active cooling function that
you can use to maintain the temperature of your living rooms
when the outdoor temperature is high during summer. Air is
a particularly good heat source for this use, generally along
with ground and ground water. For this purpose, a 4-port
diverter valve is integrated into the heat pump's refrigerant
circuit. In active cooling, the refrigerant circuit is used to ex-
tract thermal energy from the heat source installation (e.g.
the underfloor heating) in order to release it into the outdoor
air. For this, the 4-port diverter valve is used to hydraulically
swap the heat exchange processes in the evaporator and
condenser in the refrigerant circuit.
The heating water, which, when supplied, is colder in the
flow than the room temperature, absorbs thermal energy
from the rooms and is pumped by the heating pump to the
condenser (which works as an evaporator when in cooling
mode). This thermal energy is absorbed by the refrigerant
and heated to a higher temperature level using the com-
pressor. The thermal energy is then delivered to the brine
in the evaporator (which works as a condenser when in cool-
ing mode). The cooled refrigerant is guided to the expansion
valve to enable thermal energy to be absorbed from the con-
denser again. The brine pump feeds the warm brine to the
air/brine collector. The thermal energy is dissipated to the
outdoor air.
During the installation, it may be useful to exclude some
rooms (e.g. the bathroom) from the cooling function and to
actuate isolation valves especially for this. The heat pump
electronics system emits a signal that can be used for actu-
ating these.
A passive cooling module is also available as an alternative,
whereby thermal energy is transported via underfloor heat-
ing, for example, from the rooms to the ground without the
compressor operating and therefore without the refrigerant
circuit operating.
If required, the integrated electric back-up heater can be
activated at different output levels via the heat pump display.
The electric back-up heater is then actuated by the system
control.
3.2.2
Weather-compensated system control
The heat pump system is equipped with a weather-com-
pensated system control that provides heating, cooling and
domestic hot water mode depending on the control type and
controls this in automatic mode.
The control changes the target flow temperature based on
the outdoor temperature. The outdoor temperature is meas-
ured by a separate sensor which is mounted in the open air,
and the results are transmitted to the control. The room tem-
perature depends only on the preset values. The system
compensates for the effect of the outdoor temperature. Do-
mestic hot water generation is not affected by the weather
compensation. The instructions for the system control de-
scribe how to install and operate the product.
3.2.3
Display of energy consumption and energy
yield
In the display and in the app that can also be used, the
system control displays values for the energy consumption
and/or the energy yield. The system control displays an
estimation of the values for the installation. Among other
things, the values are influenced by the following:
–
The installation/design of the heating installation
–
User behaviour
–
Seasonal environmental conditions
–
Tolerances and components
External components, such as external heating pumps or
valves, and other consumers and appliances in the house-
hold are still not taken into consideration.
The deviations between the energy consumption or energy
yield that is displayed and the actual energy consumption or
energy yield may be significant.
The specifications for the energy consumption or energy
yield are not suitable to be used to create or compare energy
billing.
3.3
Safety devices
3.3.1
Frost protection function
The frost protection function for the system is controlled via
the system controller. If the system controller fails, the heat
pump guarantees limited frost protection for the heating cir-
cuit.
3.3.2
Protection against low heating water
pressure
This function continuously monitors the pressure of the heat-
ing water in order to prevent a possible loss of heating water.
If the water pressure falls below the minimum pressure, an
analogue pressure sensor switches off the heat pump and
switches the other modules, where these exist, to standby
mode. The pressure sensor switches the heat pump on
again if the water pressure reaches the operating pressure.
–
Min. heating circuit pressure:
≥
0.05 MPa (
≥
0.50 bar)
–
Min. heating circuit operating pressure:
≥
0.07 MPa
(
≥
0.70 bar)
3.3.3
Brine pressure detector
The brine pressure detector continuously monitors the fluid
pressure in the environment circuit in order to prevent a pos-
