Nibe S1155 - Heat pump function

A heat pump can use stored solar energy from rock,
ground or water in order to heat a property. The conver-
sion of energy stored in nature to property heating oc-
curs in three different circuits. In the brine circuit, (1),
free heat energy is retrieved from the surroundings and
transported to the heat pump. The heat pump increases
the retrieved heat's low temperature to a high temper-
ature in the refrigerant circuit, (2). The heat is distributed
around the house in the heating medium circuit, (3).
The temperatures below are only examples and may
vary between different installations and times of year.
100 ºC
50 ºC40 ºC
-2 ºC
0 ºC-3 ºC
-4 ºC
Heating medium
Brine
Refrigerant
Evaporator
Condenser
Expansion valve
Compressor
1
2
3
Heat source
Brine circuit
An anti-freeze liquid (brine) circulates in a hose
(collector) from the heat pump out to the heat
source (rock/ground/lake). The energy from the
heat source is stored by it heating the brine a
few degrees, from about –3 °C to about 0 °C.
A
The collector then routes the brine to the heat
pump’s evaporator. Here, the brine releases
heat energy and the temperature drops a few
degrees. The liquid then returns to the heat
source to retrieve energy again.
B
Refrigerant circuit
Another liquid 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 brine 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 consider-
ably, from approx. 5°C to approx. 100°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 origin-
al temperature. The refrigerant has now com-
pleted a full cycle. It is routed to the evaporator
again and the process is repeated.
F
Heat medium circuit
The heating energy that the refrigerant releases
in the condenser is retrieved by the heat pump's
boiler section.
G
The heating medium circulates in a closed sys-
tem and transports the heated water's heat
energy to the house water heater and radiat-
ors/heating coils.
H
NIBE S1155/S1255Chapter 2 | Heat pump function6
2 Heat pump function