Unit Functions; Principle Of Operation - Vaillant geoTHERM VWS 220/2 Instrucciones De Operación

3 Unit function and design
3.2

Unit functions

3.2.1

Principle of operation

3/4 Environmental energy
3.2 Using a geothermal heat source
Heat pump systems work on the same principle as fridges.
Thermal energy is transferred from a high-temperature
medium to a low-temperature medium and simultaneously
channelled away from the vicinity.
Heat pump systems consist of separate circuits in which flu-
ids or gases transport the thermal energy from the heat
source to the heating installation. As these circuits operate
with differing media (brine, coolant and heating water), they
are coupled to one another by means of heat exchangers.
The transfer of thermal energy takes place in these heat
exchangers.
The Vaillant geoTHERM heat pump uses the geothermal
heat source, whereas the VWW geoTHERM heat pump uses
well/groundwater.
You do not need to know the following information in order
to operate the heat pump. For those interested, however,
the principle of operation of the coolant circuit is described
in detail below.
The system consists of separate circuits which are coupled
with one another by means of heat exchangers. These cir-
cuits are:
– The brine/well water circuit with which the thermal
energy is transferred from the heat source to the coolant
circuit.
8
– The coolant circuit, which releases the accumulated ther-
mal energy to the heater circuit by means of evapora-
tion, compression, liquefaction and expansion.
– The heater circuit, which supplies the heating and DHW
loading for the domestic hot water cylinder.
1/4 Electric energy
installation
4/4 Heat energy
Diverter valve
Heater/
cylinder
charging
Brine pump/
well pump
3.3 Principle of operation of the heat pump
The coolant circuit is connected by means of the evapora-
tor (1) to the heat source, from which it extracts thermal
energy. At the same time, the physical state of the coolant
changes; it evaporates. The coolant circuit is connected by
means of the condenser (3) to the heating installation, to
which it releases the thermal energy again. In so doing, the
coolant becomes liquid again;
it condenses.
As thermal energy can only pass from a body at a higher
temperature to a body at a lower temperature, the coolant
in the evaporator must have a lower temperature than the
heat source. On the other hand, the temperature of the
coolant in the condenser must be higher than that of the
heating water in order to be able to release the thermal
energy to it.
These different temperatures are produced in the coolant
circuit by means of a compressor (2) and an expansion
valve (4) between the evaporator and condenser. The cool-
ant flows in vapour form from the evaporator into the com-
pressor, where it is compressed. This causes the pressure
and temperature of the coolant vapour to rise sharply. After
this process, it flows through the condenser, where it
releases its thermal energy to the heating water by conden-
sation. It flows as a liquid to the expansion valve, where it
expands significantly and in so doing loses much of its pres-
sure and temperature. This temperature is now lower than
Cold water
Heating
Electric
auxiliary
heater
3
Condenser
Expansion
Compressor
valve
Evaporator
4
1
Heat source
Operating instructions geoTHERM 0020051578_03
Domestic
hot water
Domestic
hot water
cylinder
Heating circuit
2
Coolant
circuit
Brine circuit/
well water circuit