Geothermal heat pump installation location and preparation

Hello,

the sanitary and electrical installers are now speeding things up and want to have everything finalized before the heating installer is ready. Therefore, I need to clarify the following questions as soon as possible:

1. Location of the ground source heat pump: There are generally 2 possibilities in my basement

A: Room facing the garden. Then the connection to the brine circuit in the garden would be shorter. But on the other side of the house from the water connection and the kitchen & bathrooms above.
B: Room facing the street side. The heating would then be directly next to the water supply & drainage as well as directly under the kitchen and bathrooms (short pipes). The risers are located nearby in this room. The connection to the brine circuit would be longer. Either lead out sideways and then to the back into the garden or lead back through the basement and then through the exterior wall into the garden there.

I had planned position B because it seemed clearly better to me due to the shorter pipe runs. I’m only confused because two heating installers who were on site did not expressly favor this position. It was more like... yes, that could work... and... both would somehow be possible...

How do you see it? Is B clearly better than A?

2. Preparation of electrical connection

I would like to have a Nibe S1255-PC. I have the feeling that the heating installer will only deal concretely with my system once he has a foreseeable delivery date. So far I have no exact specifications here, only information from the internet.

For the electrical connection I have now planned
1x 5x2.5mm NYM (compressor)
1x 5x1.5mm NYM (heating element)
1x 4x0.8mm ??? (outdoor sensor)
1x LAN Cat7 (network)

Have I forgotten something here? Does the circulation pump need a separate 230V connection cable? I don’t think so, right? How is the transfer point usually designed? Simply open cable ends with sufficient length or some kind of transfer terminal or installation box?

3. Preparation of heating connection
I think my heating installer mentioned an "connection panel" here, could that be? Unfortunately, I didn’t note the technical term and can’t find anything suitable under that term. What is it usually called? Because of the passive cooling, there should be something special on it. What would that be? Is it normally installed by the sanitary installer?

I would appreciate some helpful answers.

Best regards Julian

I would favor position A or B with immediate wall breakthrough - the brine pipes must be insulated very carefully (including against condensation), the shorter the paths inside, the better. This also applies to hot water/domestic water and heating, but to a lesser extent.

The heat pump requires a bit more than you planned:
- Besides the external sensor, you also have 1 x internal sensor included (both 3x0.75 Olflex or similar)
- If you want, there is also the indoor unit (RMU S40), which can serve as both control and room sensor (4x0.75 Olflex or similar)
- For network cables, better take duplex, then you can use one for tariff switching (if ever desired, then + 3x1.5 mm2 control voltage)
- Compressor + heating element should, I think, be installed with 5x4 mm2 (depends on cable routes & installation type)

The connections are assigned internally to terminal blocks, so open cables make the most sense.

If you have circulation, you may need to consider whether the circulation pump is controlled by the heat pump (then you can connect it directly), or whether you prefer to do this externally, then you need an additional 230V socket somewhere nearby.

The compressor probably doesn't need 2kw. Why 2.5mm² and even more question marks at 4mm²?!

The heating element maybe has 8kw, even there it doesn't need special cables for the few times this thing runs per year?!

I meant, only 1 x 5x4 mm2 for both (I assume we are talking about the 3x400V version, which is standard offered/installed in Germany). Maybe 2.5 mm2 is also possible, but depending on the cable length and installation method, that can be too tight - and 4 mm2 costs almost "nothing" if you do it right in the shell construction phase.

I oriented myself on the 2.5mm2 based on the detailed planning of an acquaintance. He is also currently building and is getting an 8kW Bosch heat pump. It is a core renovation, so no electrical installations have been laid yet, which allows me good control. Possibly, I could then reduce to a single cable 5x4mm2. Strange that the other plan included 2 cables. Securing heating element and compressor separately in the distributor is usually not done?

I’m a bit surprised that you prefer position A. From B, I could also go directly through the outer wall. Depending on where the drilling is done (so far everyone seemed to prefer the rear garden), I would then only have slightly longer supply lines running along the side of the house outside in the ground.

Could someone say something about the handover point heating / house installation? What is it called? And what do I have to especially consider for passive cooling?

Best regards

I oriented myself on the 2.5mm2 in the detailed planning of an acquaintance. He is also currently building and is getting an 8kW Bosch heat pump. It is a core renovation, so no electrical installations have been laid yet, which allows me to still control it well. Perhaps I could then reduce it to a single 5x4mm2 cable. Strange that the other plan had 2 cables in it. Is it uncommon to protect the heating element and compressor separately in the distribution box?

You can supply the electric cartridge separately, but in my opinion, it only makes sense if you want or have to install a utility lockout, and your power supplier absolutely wants to cut the power supply for that. Of course, it is much smarter to do everything via switching contacts (hence the recommendation to provide either signal cables or CAT cables in addition). You can lay 5x1.5 mm2 for a control voltage anyway, additionally, which can be installed cost-effectively together with the 5x4 mm2, and then you have all options open.

That you prefer Pos. A surprises me a bit. From B, I could also go directly through the outer wall. Depending on where the drilling is done (so far everyone seemed to prefer the back garden), I would then only have somewhat longer supply lines along the side of the house outside in the ground.

I meant either A or B, but directly through the outer wall. If B is not significantly more expensive or problematic regarding earthworks & later restrictions on planting, you can of course choose B. However, this should be discussed in advance with your drilling company, as there are a few details that might still play a role, e.g., bending radii at direction changes as well as the usually desired slight slope toward the house entry so that the cable is vented there.

Could someone say something about the handover point heating / house installation? What is it called? And what do I have to pay special attention to regarding passive cooling?

No idea what is meant – hot water & heating flow/return are connected directly to the heat pump (of course with appropriate shut-off options and filters, manometers, expansion vessel, etc.); I wouldn't know what would be different with passive cooling (I don't have it myself, though...). Maybe sensors / dew point monitoring? Depending on the concept, one could place it there, although in my opinion it makes more sense to place it in the rooms themselves (or if you want to be very precise, in the floor structure).