Nibe F2040 - Page 13

An air/water heat pump can use the outdoor air to heat a property. The
conversion of the outdoor air's energy to property heating occurs in three
different circuits. In the brine circuit, (1) , free heat energy is retrieved from
the surroundings and transported to the heat pump. In the refrigerant
circuit, (2) , the heat pump increases the retrieved heat's low temperature
to a high temperature. In the heating medium circuit, (3) , the heat is dis-
tributed around the house.
Outdoor air
The outdoor air is sucked into the heat pump.
A
The fan then routes the air to the heat pump’ s evaporator. Here, the air releases
the heating energy to the refrigerant and the air's temperature drops. The
cold air is then blown out of the heat pump.
B
Refrigerant circuit
A gas circulates in a closed system in the heat pump, a refrigerant, which also
passes the evaporator. The refrigerant has a very low boiling point. In the
evaporator the refrigerant receives the heat energy from the outdoor air and
starts to boil.
C
The gas that is produced during boiling is routed into an electrically powered
compressor. When the gas is compressed, the pressure increases and the gas's
temperature increases considerably, from 5 °C to approx. 80°C.
D
From the compressor, gas is forced into a heat exchanger, condenser, where
it releases heat energy to the heating system in the house, whereupon the
gas is cooled and condenses to a liquid form again.
E
As the pressure is still high, the refrigerant can pass an expansion valve, where
the pressure drops so that the refrigerant returns to its original temperature.
The refrigerant has now completed a full cycle. It is routed to the evaporator
again and the process is repeated.
F
Heat medium circuit
The heat energy that the refrigerant produces in the condenser is retrieved
by the climate system's water, heating medium, which is heated to 55 °C
(supply temperature).
G
The heating medium circulates in a closed system and transports the heated
water's heating energy to the house water heater and radiators/heating coils.
H
The temperatures are only examples and may vary between different installations and
time of year.
11NIBE™ F2040Chapter 2 | The heat pump – the heart of the house