ᐅ Depth of the trench collector for a ground-source heat pump with brine-water system

Hello everyone,

I am currently in the planning phase for the building services. Our site is currently about 2 m (6.5 ft) below the ground floor level but may be filled up to this level.
When I enter a depth of 2 m (6.5 ft) for the trench collector in the trench planner, a warning appears: "Danger to life."
I assume this warning mainly refers to the safety of the trench during construction. Are there any other technical reasons for this warning? Basically, I thought: the deeper, the better – or am I mistaken?
Of course, it is important to ensure that the pipes can withstand the mechanical pressure. But based on intuition, a depth of 1.7 m (5.6 ft) or 2.0 m (6.5 ft) should not make much difference, right? The soil is clayey and rocky.

I mean, if you dig too deep, the trench will not warm up again in summer or will do so only very slowly, which could potentially be a disadvantage.

mr.rider schrieb:

But just going by feel, 1.7 m and 2.0 m depth shouldn’t make much difference, right? The soil is clayey and rocky.

Of course, those 30cm (12 inches) do cause additional loss in regeneration. However, you can compensate for that over the length. Ultimately, the key is to be deep enough to avoid accidentally damaging the collector and high enough to ensure sufficiently good regeneration. Surface vegetation, shading – all these factors also play a role. From a technical standpoint, 2m (6.6 feet) is definitely feasible.