Cooling with heat pump via underfloor heating?

That means adjusting the flow rates twice a year.

We handle it the same way with the passive cooling. The only change I make to the flow is the reduction in the bath to 1.0 l/min (from 2.5). I do that manually. I leave the rest as is.

how deep? how many pipes? (sorry if it's a bit off-topic)

As deep and as many pipes as necessary so that the cabin is warm in winter according to the heating load calculation.

We are only looking for a solution for one problem. Since the heating circuits are adjusted according to thermal balancing, the required flow rate reverses during cooling. The bedroom has the lowest heating water demand but the highest cooling demand. That means adjusting the flow rates twice a year. Are there actually control valves that can hold intermediate positions?

We also have a brine heat pump with passive cooling, which we have not used so far. I wouldn’t even know how to set it, but the above point has crossed my mind as well. With cooling demand, one would strive to avoid cooling the bathroom and instead cool the bedroom more.

Can’t this be enforced through individual room control? For example, a high setpoint temperature in the bathroom during cooling operation should lead to a reduced flow rate. How does this work with cooling operation? How do you adjust the individual room controllers?

Disclaimer: I know that individual room controllers are rubbish and you do a "fixed" hydraulic balancing. We do that in heating mode as well, and our individual room controllers are de facto redundant (but still present due to regulations). Could these stupid things at least be used sensibly during cooling? At least with passive cooling, any possible inefficiency due to non-optimal flow would be irrelevant.

Can't this be enforced through the individual room control?

Not really. Of course, you can set the target temperature very high, then the valve remains closed permanently and it won't cool. But in the bedroom? Then the valve is always open, but because of the low flow rate (since there is also little heating demand in winter there), the cooling is only mild. Therefore, the flow regulator must be turned up there, because the RTRs can only be on or off.

How does cooling operation work? How do you adjust the ERRs?

It's in the heat pump manual. Switch the mode to cooling, then the RTRs adjust themselves. Of course, you need suitable ones that can do this.

Disclaimer: I know ERRs are crap

I have nothing against them. They can even be quite useful. Ours, for example, have a display and show room temperature as well as the time :D

Ours, for example, have a display and show the room temperature as well as the time :D

I use this function too ;)

You are of course right about the bedroom; there you'll probably have to increase the flow manually. The bathroom and everything else should work via RTR. The only thing missing is summer to try it out :rolleyes:

I have throttled the bath, tiled floor with the valve fully open, showering with cold feet is not so great. But I am also a hot shower person, it has to steam :p