elco Aquatop TC Series, Руководство по эксплуатации, Страница: 18 / 48

18
Charging Geothermal Heating Systems
Problems and Issues
Incorrect Brine Concentration
Flushing
Problems
Problems with charging a geothermal
heating system (GHS) with antifreeze
may occur occasionally and result in a
reduced capacity of the system or even
total system failure. Most problems are
as follows:
Dirt in the Circuit
Drilling companies generally strive to
fill only clean water into geothermal
heating systems. However, dirt may
reach the probe due to inattention.
This dirt can damage the circulating
pump or the evaporator of the heat
exchanger.
Insufficiently Mixed Brine Solution
If the correctly calculated antifreeze
volume is charged directly as a concen-
trate without corresponding mixing
device, individual probes may jam or
become completely disconnected due
to the viscosity of the concentrate.
Water without the required glycol
content circulates in the remaining
probes. Without the required glycol
content, the heat pump may freeze
already upon initial startup, which may
destroy the associated evaporator.
Incorrect Brine Concentration
In some cases, the detected glycol
concentration differed greatly from the
calculation.
This was mostly due to a lack of the
proper equipment to prepare the
mixture correctly. If the concentration
is too high, the heat pump's capacity is
reduced and works less efficiently.
The heat pump may also overheat.
An insufficient concentration (<20%)
may cause corrosion and frost damage.
Correctly Charging the GHS with the
Help of a Mixing Tank, Mixing
Equipment with Filter
All of the problems listed previously
can be avoided by properly charging the
GHS circuit. The right equipment can
make all the difference as well.
Use a mixing and charging tank to
charge the GHS circuit according to
the following requirements:
- Clean
mixture
- Correct concentration:
- Homogeneous mixing
Flushing
Use filtered potable water and pres-
sure to flush first the circulating pump
of the GHS circuit and the evaporator
and remove pollutants such as welding
beads, little stones, and dirt.
After closing a slider in the heat pump
circuit, each circuit of the GHS is
flushed one after the other.
A pressure of 2 bar is used to flush
a 140-m long ø 32 mm probe for
6 minutes as depicted below.
Min. Flushing
Time for 32-mm Probe
10
9
8
7
6
5
4
3
2
1
0
0 50 100 150 200
Probe length
D
urati
on
in
m
inu
tes
2 bar pressure
3 bar pressure
Charging hose
Excess pressure
valve 2.5 bar
Mixing
tank
120 l
Jet pump.
e.g. Grundfos
max. 5 m
3
/h
max. 5 bar
GHSs
Brine circulating pump
Heat pump
Expansion vessel
GHS circuit
Drain hose
Filter