Experiences with brine heat pump

Thanks Mastenmind1 for the explanation - principle understood .... basically we have a fixed setting on the regulators in the house and never touch them. The bedrooms are set to zero, as is the guest room, which is the only one modified depending on the situation. The rest is constant.

I have one more question, if the lady of the house wants a cozy warm bathroom floor. Lower the base temperature and turn the room thermostat up fully or increase the base temperature and lower all the other regulators in the house?

The second option causes your heat pump to run only very short cycles, because closing all the regulators in the house faster, except for the bathroom, means it doesn't heat the bathroom either, since the minimum flow rate of the heat pump is not reached.

Thanks Mastenmind1 for the explanation - principle understood .... basically we have a fixed setting on the controls in the house and never touch them. The bedrooms are set to zero, as is the guest room, which is the only one modified depending on the situation. The rest is constant.

I have one more question, if the lady of the house wants a cozy warm bathroom floor. Lower base temperature and turn the room thermostat up fully or increase the base temperature and lower all other controls in the house?

Cozy warm means a surface temperature higher than body temperature. That is crazy.
Underfloor heating does not make hot feet.

Your second option would come closest to the goal, but it is uneconomical.

Cozy warm means a surface temperature higher than body temperature. That is insane.

When outdoor temperatures drop deeply in winter, so that the supply temperature is >= 30°, then the tiles in the bathroom are already pleasantly warm, not only at >37°. Most of the year they are rather "imperceptible". You only notice the difference when you step on tiles that have no heating underneath (e.g. utility room).

The approaches are exactly right. Maximum openness of all circuits results in a low supply temperature and then, through a high hysteresis, a möglichst lange Laufzeit. You can cook pasta at 99 degrees, it takes 10 minutes, or at 50 degrees, it then takes 5 hours. The heat pump runs best as cold as possible, but then you only get the heat into the house with a long running time and lots of open circuits. So also open the circuits in the bedroom all the way. Tip: Buy a cheap infrared thermometer. Then stick a masking tape strip on each return pipe of the underfloor heating. After a long running time (weather not good for it right now!) measure the differences. Where it is significantly warmer, you have too much flow. I did it this way in two houses and brought my heating cycles to 4 hours.

A question out of turn for the experts here: Wouldn't it make sense for the following scenario to do the following: If I want a) bathroom especially warm, b) living rooms normal, c) bedrooms especially cool, to simply adjust the density of the heating pipes per sqm of floor in the rooms (bathroom particularly dense, bedrooms particularly sparse) and then just run the heating in the whole house at the same level?

Here it sounds as if I would get the most efficient solution for technical reasons?

that's how you do it, yes