Help with choosing the type of heat pump

OK. Thanks already for the feedback. The facts in the first post are definitely wrong. Let’s let it slide ;-)

Homework for me: I had the topic [Grabenkollektor] on my radar before but forgot about it again. It seems very appealing to me. I need to rethink the second electricity meter. That was my first instinct. But I can follow and agree with the argumentation. Topic [Grabenkollektor]: Does it have any disadvantages? Everything I quickly read about it sounds too good to be true :)

The collector is relatively close to the surface, the heat is supplied by the sun. This usually means it cannot be built over and shading should also be avoided. Deep-rooted plantings are also taboo.

We are still considering and waiting for concrete offers. We have more than enough land, but who likes to permanently restrict themselves?

We installed a surface collector as a DIY project. We did it on the side, while there was already a large excavator on site. I would do it again anytime. At the same time, we also installed a drainage system for rainwater drainage above it. It's supposed to be good for the collector, and drainage makes sense anyway to pay less fees.

Disadvantages? You shouldn't build or seal over the surface. Since heat is extracted from the ground, supposedly less grows above it. So far, we haven't noticed any difference, but we've only lived in the house for one year. The biggest disadvantage is probably the space requirement. We have the space and therefore laid generously 7 PE pipes with a length of about 90m each for 160 sqm of heated area. The distance between them is 0.7 m. The space required was about 400 sqm including a shaft for the distributor etc. Obtaining the permits was quite nerve-wracking (Lower Water Authority...). But your plumbing company should take care of this (we did all plumbing ourselves because we have an expert in the family).

What worked quite smoothly, on the other hand, was the funding. The money arrived very quickly (€4,500).

In the picture, you can see the last 3 PE pipes being laid.

Thank you very much for your feedback. Assuming I have a ring trench collector in the garden, at what distance can I start planting trees again? Assumption: The collector is located at a depth of 1.5m.