Vaillant geoTHERM VWS 61/2, Operating Manual

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Operating Manual geoTHERM VWS/VWW 0020051547_02
8
4 Equipment and functional
description
4.1 Functional principle
Heat pump systems consist of separate circuits in which
fluids or gases transport the heat from the heat source
to the heating system. As these circuits work with dif-
fering media (brine/water, coolant and heating water),
they are coupled with one another by means of heat ex-
changers. In these heat exchangers, heat passes from a
medium at higher temperature to a medium at lower
temperature.
The Vaillant geoTHERM heat pump uses geothermal en-
ergy as its heat source.
3/4 Environmental energy 4/4 Heating energy
1/4 Electrical energy
Fig. 4.1 Using a geothermal heat source
Auxiliary
heating
Domestic hot
water cylinder
Heating water circuit
Heat source circuit
Coolant circuit
Hot water
Cold water
Diverter valve
Heating water pump
Condenser
Heat source
Brine pump
Evaporator
Compressor
Expansion valve
2
1
3
4
Heating system
Fig. 4.2 Mode of operation of the heat pump
The system consists of separate circuits which are cou-
pled with one another by means of heat exchangers.
These circuits are:
- The heat source circuit, by means of which the energy
from the heat source is transported to the coolant cir-
cuit.
- The coolant circuit, from which heat is passed to the
heating water circuit by means of evaporation, com-
pression, liquefaction and expansion.
- The heating water circuit, which supplies the heating
and the hot water generator for the domestic hot
water cylinder.
4.2 Operation mode of the coolant circuit
The coolant circuit is connected by means of the evapo-
rator (
1 ) to the geothermal 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 system, to which it releases the heat again.
In so doing, the coolant becomes liquid again; it con-
denses.
As thermal energy can only pass from a body at a high-
er temperature to a body at a lower temperature, the
coolant in the evaporator must have a lower tempera-
ture than the geothermal 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 heat to it.
4 Equipment and functional description