1.6 Operating principle
The heat pump transmits the energy contained in the
surrounding air into the dwelling to be heated.
The heat pump consists of four main elements, in which
a refrigerant (R410A) circulates.
- In the evaporator (ref. 12, gure 10, page 14):
The calories are taken from the outside air and
transmitted to the refrigerant. Because it has a low
boiling point, it changes from a liquid to a vapour, even
in cold weather (down to -20°C outside temperature).
- In the compressor (ref. 9, gure 10, page 14):
The vaporised refrigerant is pressurised and takes on
even more calories.
- In the condenser (ref. 14, gure 11, page 15):
The energy of the refrigerant is transmitted to the
heating circuit. The refrigerant returns to its liquid state.
- In the expansion valve (ref. 8, gure 10, page 14):
The liqueed refrigerant is returned to a low pressure
and regains its initial temperature and pressure.
The heat pump is equipped with a controller which
controls the room temperature based on the outdoor
temperature measurement. The room thermostat
(option) provides a corrective action for the temperature
control.
The hydraulic unit is tted with an electrical backup or
boiler connection* which intervenes to provide additional
heat during the coldest periods.
• Control functions
- The heating circuit's ow temperature is controlled by
the temperature control.
- Depending on the heating ow temperature,
the outdoor unit's power is modulated by the "Inverter"
compressor.
- Control of the backup electrical heating*.
- The daily timer program is used to set the periods
where the ambient temperature is comfortable or
reduced.
- Summer/winter time mode switchover is automatic.
- Management of the boiler backup*.
- Room sensor*: The room sensor provides a corrective
action for the temperature control.
- Control of a second heating circuit*.
- Domestic hot water*: Heating timer program,
management of the DHW circulation pump.
- Managing cooling*.
* Where the heat pump is tted with options and associated kits.
• Protective functions
- Anti-legionella cycle for domestic hot water.
- Frost protection: Frost protection cuts in if the heating
circuit's ow temperature falls below 5°C (provided
that the heat pump's electrical power supply is not
interrupted).
8
7
6
5
4
3
2
1
0
-20 -15 -10 -5 0 510152025
46
Dwelling heat loss (kW)
Outdoor temperature (°C)
Outdoor temperature (°C)
HP power
gure 12 - Examples and operating limits
Max
authorised HP
start-up temp.
Water return temperature (°C)
HP only
Heat Pump
HP +
electrical
backup
Backup
Installation manual "1872 - EN"
Alféa Extensa A.I. Heat Pump
- 16 -