ᐅ Ground loop collector – is it necessary to replace the fluid or pipes?

Hello everyone,

we are currently planning to build our house as well. A builder recommended a heating system with ground collectors because we have a large plot of land (about 1000 m² (10,764 sq ft)).

Now my questions:

Is it necessary to regularly change the fluid in the ground collectors, just like with collectors on the roof?

Do the pipes in the ground collectors also need to be replaced after about 20 years, like roof collectors, or are they installed once and then maintenance-free?

I would appreciate any answers.
Best regards,
Andre

Hello,

andre02 schrieb:
....we are currently planning to build our house. A builder recommended a heating system with ground collectors because we have a large plot of land (around 1000m² (10,764 sq ft)).

Basically, this is a reasonable suggestion. For ground heat collectors, apparently surface collectors in this case, the annual required extraction capacity and energy, as well as soil type, must be known.
Only based on this can the sources be properly sized. Undersized systems lead to poor annual performance factors. Oversized systems mean money is wasted unnecessarily.
One must not forget restrictions on building coverage and possible limitations in land use.

andre02 schrieb:
...Do you have to regularly change the fluid here as well, like with roof collectors?

No.

andre02 schrieb:
...or do you install it once and then have no worries forever?

Yes!

Best regards.

Hello €uro,

first of all, thanks for the quick response.

We don’t know the annual heating capacity and energy needed, nor the soil type. The consultant only calculated that we need 6480 watts and would have to lay out 243m² (2617 ft²) of piping for that. Could that be correct?

Regards, Andre

Hello,

andre02 schrieb:
...We do not know the annual heating demand and energy required, nor the soil type, ...

In that case, it is not possible to properly size a ground source heat exchanger.

andre02 schrieb:
...the consultant only calculated that we need 6,480 watts and that 243m² (2,615 ft²) of area with piping must be installed, ...

What exactly is the 6.48 kW rating referring to? Does this calculation comply with DIN EN 12831? Is there a mechanical ventilation with heat recovery (MVHR) system in place, and has there been an agreement on the desired indoor temperatures?

Best regards.

Hello,

there is no DIN standard listed; it’s just a rough note, but as far as I understood, the calculation was as follows:

Living area of 160 m² (1722 sq ft) corresponds to a heating load of 285€ which equals about 4480 W
4 people correspond to a hot water demand of 200€, which equals 2000 W
total 485€ per year, and 6480 W per year
with 6480 W, he then calculated 243 m² (2615 sq ft), but don’t ask me how.

By now, we don’t know what the best heating system is. Yesterday we visited another builder who immediately discouraged us from geothermal energy with collectors. He said the effort to lay the pipes is not worth the benefit. He recommended gas or an air-to-water heat pump. Now we probably have to choose a system ourselves without knowing if it’s the best option or not.

Regards,
Andre

Hello,

andre02 schrieb:
....so there is no DIN standard on it, it’s just a rough note ...

It’s surprising how many inexperienced people get impressed by such rough notes and even sign contracts worth tens of thousands of euros based on them 😕

andre02 schrieb:
....By now, we no longer know what the best heating system is.

There isn’t a single best system, but usually a particularly sensible solution. To find that, a preliminary assessment must be carried out first. This is definitely much more complex than just filling out any random rough note. 😉

andre02 schrieb:
....Yesterday we visited another builder who immediately discouraged us from geothermal heating with collectors. He said the effort to install the pipes does not justify the benefits.

The more builders you visit, the more potential options you will get. Naturally, each one promotes their concept as the best all-around solution. 😉

andre02 schrieb:
....He recommended gas or an air-to-water heat pump.

Such recommendations without reliable data are usually unfounded and primarily reflect the interests of the seller.

andre02 schrieb:
....Now we probably have to choose a system ourselves without knowing if it is the best one or not.

This can be easily resolved. First, a clearly defined building shell (building components) is required. There are plenty of ideas, proposals, and offers available for this. Based on this “framework” together with the building’s climate location data, site orientation, user behavior (room temperatures, hot water demand, etc.), the actual demand (capacity, energy) for heating, hot water, and possibly ventilation is determined. This should be done by an external mechanical, electrical, and plumbing (MEP) engineer and energy consultant independent from sales. Once the figures are known, the cost-effective optimal solution can be found relatively quickly. A comparison of options is usually recommended. It is not uncommon that slight adjustments to the building shell are advantageous afterwards.

Best regards

PS: Saving on energy costs often starts with the choice of building plot!