What is the appropriate spacing for floor cooling installation?

@11ant you talked about the whole planning. That also includes heating. Unfortunately, your other statement doesn’t help me further. Can you specifically name what the catastrophic consequences of the planning are?

Whatever "other statement" might be meant, I did not speak of a "catastrophic planning," but we probably simply talked past each other.

I am fully aware that the planning has clear potential for improvement. But this improvement potential always tends towards a lower flow temperature for heating and possibly a slightly better cooling effect. If you see other disadvantages that result from this planning, I would be very happy if you could explain them.

So let’s start anew – I think the thinking got stuck somewhere. So a floor heating system with cooling function is to be installed – ONE heating and cooling system, not one heating AND one cooling system. So there is only ONE network / one medium. And logically, only ONE installation spacing – you can’t switch that between "heating" (=heat emission) and "cooling" (=heat absorption). Let’s further assume that different agility is desired for the functions "heating" and "cooling," in order to offer one of the functions "faster" / "less sluggish." Same medium, same pipe length or the same installation density are given to us by ONE common network. Within this framework, between the modes "(forward) heating" and "cooling = reverse heating," only either uneven surface areas can provide different performance or different pump speeds can be set to "shift gears." Let’s assume the case that cooling feels sluggish with a network designed for heating. Then in cooling mode either the flow rate in this network must be increased, or additional cooling surface is required, which is then switched on as a "turbo mode." That would probably be most sensible as a floor heating and cooling system with an installation spacing optimized for heating for normal operation, and for turbo operation a ceiling cooling, for example above the seating area and the dining table or possibly near the extractor hood. I don’t see other sensible approaches in practice to the dream desire of a magically adjustable installation spacing – luxury has to remain affordable somewhere. To summarize: if one wants to cool "faster" than one can heat in a dual-function network, it requires either a variable flow rate of the same transport medium or a larger cooling surface than heating surface – in other words: an additional surface at the ceiling in cooling mode.

Well, I have seen worse calculations. The only obvious disaster is once again the bathroom.
And not just the pipe spacing but especially the circuit length. Over 100m precisely in the bathroom is really not good.
The 150W underperformance is already indicated and is probably even higher in reality.
At least split that into two circuits. That only costs one extra valve.

How does it look in the shower/toilet room downstairs? That looks catastrophically short..

We have planned an infrared auxiliary heater on the ceiling in the bathroom. It only has 700 watts but hopefully that should be sufficient. We also wanted to split the heating circuits already but the general contractor keeps referring to the manufacturer and the manufacturer says heating circuits including the connection line may be 120 meters long. We are—counting the area under the bathtub—at 117 meters length. I will bring it up again.

The shower/toilet on the ground floor has a length of only 42 meters. The room is also very small with 3.3 m². There we will install a mirror with an integrated infrared heater.

We really talked past each other there. I referred your statements

The "construction" shown in the plans seems to me like a fool’s errand / practical joke close to the Flat Earth Theory *LOL* [...]

[...] Regarding question 1, I seriously wonder, highly concerned, how much of the general school education still common "in my time" must have been lost to develop such a plan at all without realizing what kind of substances one must have been on to come up with those ideas *shaking my head*

referring in general to our underfloor heating planning. Of course, I understand your point that heating via underfloor heating and cooling via the ceiling is a much more sensible solution. Unfortunately, I am not aware of any ceiling cooling option for wooden ceilings.

... referring generally to our planning of the underfloor heating. Of course, I understand your objection that heating via underfloor heating and cooling via the ceiling is a much more sensible solution. Unfortunately, I am not aware of any ceiling cooling option for wooden ceilings.

there are cooling sails that can be hung under the ceiling. They also come in "nice" designs, as picture or decorative objects.

And please don't see the commercial amortization as an exclusion criterion. If you want to have the comfort of efficient cooling and it costs 2K (for a "lifetime" extra luxury), then do it if you can afford it. Otherwise, you just fly one less time on vacation.

P.S.: With an air-to-water heat pump, cooling costs extra electricity; a brine-to-water heat pump can achieve passive cooling up to about 3°. That's how I had my wall heating designed, which can also cool. Just not both at the same time. It worked quite well last hot summer. If you want more, you rather need an air conditioning unit because further cooling eventually becomes impossible (condensation formation).

I of course understand your objection that heating via underfloor heating and cooling via the ceiling is a much more sensible solution.

No, I proposed heating and cooling via the underfloor heating, and to create additional cooling surfaces to cover peak cooling demands. To avoid competition for floor surface resources (and because cold air falls better), I suggested placing this second "heating-cooling circuit," which is only activated in cooling mode, on the ceiling.

Unfortunately, I am not aware of any ceiling cooling options for wooden ceilings.

But there must be such options; as far as I know, the timber construction company Huf has equipped a project in Montabaur consisting of several residential and office "multi-family houses" with this technology.

There are cooling sails that can be hung under the ceiling. They also come in "nice" versions, designed as picture or decorative objects.

Thanks for the hint, I didn’t know that. So far, I have only seen such solutions for industry. I’ll look into it.
But I assume these solutions also work with water flow and are therefore hard to retrofit, right?

And please don’t see the commercial amortization as a disqualifying criterion. If you want the comfort of efficient cooling and it costs 2K (for a "lifetime" extra luxury), then do it if you can afford it. Otherwise, you’ll just skip a vacation once.

The amortization calculation only referred to the heating costs. If I had the option to invest 2K to be able to cool much more efficiently, I would do it. But unfortunately, I don’t see that option at all. Even if we reduced the installation spacing everywhere to 10 cm – the effect for cooling via the floor would probably be limited.

Understood – thanks :)

I am very sure that 15 or 10cm makes no difference when cooling. Flooring could be a problem. With our glued vinyl, it works wonderfully with 15cm. The bigger problem with cooling using radiant floor heating is almost always the moisture eventually. It does not get better if you include walls and ceiling. Efficiency is clearly less important when cooling than when heating. Cooling is needed much less often in the first place and secondly you almost always have enough photovoltaic power for it. So make sure you get the circuit in the bathroom divided. Feel free to pay for it. You are building a house for a lot of money that should work well for many years.