The deepening groundwater level in Munich is causing increasing problems – among other things, expensively purchased heat pumps can no longer function. (Symbolic image) © Heinz Gebhardt / IMAGO
In Munich-Waldperlach, property developers are struggling with the falling groundwater level. This ensures that heat pumps fail. And there is a lack of suitable alternatives.
Munich – It's bitter when you don't have a functioning heating system despite your modern groundwater heat pump. This is exactly what happened recently in an apartment building in the eastern Munich district of Waldperlach. The groundwater heat pump no longer worked because the associated well dried up due to the low groundwater level.
It is even more bitter when there is no real solution to the problem. The owners' association of the apartment building has opted for a new heating system – which, however, must be operated with gas.
The groundwater problem does not seem to be an isolated case in Waldperlach. A property management company reports that they are in the same dilemma. "One street away, we have exactly the same problem with groundwater heat pumps," says Johannes Zimmermann, owner and managing director of saceba Immobilienverwaltung.
Falling groundwater level poses problems for property developers: heat pump filters clogged
The problem first occurred in August last year: the groundwater heat pumps failed because the groundwater level was too low. "When the groundwater level drops, very fine sand is pumped along, which clogs the heat pump filters," explains Zimmermann.
Since then, the filters of the pumps have had to be rinsed out regularly. However, this is only a temporary solution, not permanent. Because sooner or later the filter will break completely. So far, that hasn't happened, but Zimmermann fears that things won't go well for much longer.
According to Zimmermann, the wells for a groundwater heat pump are usually drilled 18 to 20 meters into the depth. The latest ones are now already at 22 meters, because the groundwater level has dropped by about four meters. In Waldperlach, however, there is a barrier in the ground, deeper could not be dug.
Groundwater heat pumps fail: No long-term solution and few alternatives
Another way to keep the groundwater heat pumps in operation is to reactivate the well for about 3000 euros. The filter is cleaned and the pump is lowered a little, Zimmermann knows. However, this solution does not bring security either, he says. This is because the groundwater level could continue to fall.
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The situation is very annoying for everyone involved, because actually the system of these heat pumps would be perfect: "They are super efficient and the electricity costs are cheap." According to the managing director of the property management, air source heat pumps, on the other hand, are much more expensive and cannot compensate for peaks. Apart from the fact that these are currently not available at all.
Zimmermann sees installing a gas heating system as an absolute no-go. "This is not an alternative, we want renewable energy." District heating would be the only alternative here, he says. But the relatively small apartment buildings with 6 to 15 parties are of no interest to the municipal utilities. "There is no foreseeable expansion of the network here," he regrets. Nothing is progressing.
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Problems caused by falling groundwater levels: Developers plan with complex hybrid heating
The only option that remains: a complex and expensive hybrid solution. This is a combination of gas, air and solar heating. "The boiler room is then jam-packed," says Zimmermann. "There are three systems that need to be checked and maintained. The running costs are immense and the whole thing is incredibly time-consuming."
As Zimmermann explains, groundwater heat pumps are still part of current construction projects due to long-term planning. However, current plans no longer include groundwater heat pumps. Here, property developers are now forced to rely on the hybrid alternative.
"We need an alternative quickly," says Zimmermann, summarizing the difficult situation of owners, property developers and property managers. "Not in months, but now."
As early as January, the low groundwater put the heat pump of a Neubiberg couple out of action. A new heating system, which is operated by an air source heat pump, will not be available until autumn. The costs are in the five-digit range. (lea)
You can find even more up-to-date news from Munich and the region on tz.de/muenchen.