Geothermal heating with cooling function - adjustable?

I would put it this way: if the whole house is insulated well enough, it is definitely possible to keep the house at temperature (cooling requires "somewhat" more power). I did a calculation for my case: I have an average U-value of 0.17 with 465m² surface area and a temperature difference of say 10°C (24°C -- 34°C), which results in around 790W of thermal heating power. BUT: according to my energy certificate, I have solar gains of 777kWh in August, with an average of 7.1 sun hours per day in August that means an average output of 3.4kW, which heats the house for 7.1 hours a day. And in total about 4.1kW of cooling capacity --> that is quite a lot. For example, if you run the underfloor heating with 15-16°C supply temperature, you will depending on conditions already have condensation on the cold floor, apart from the fact that the floor feels cold: at 30°C / 50% relative humidity the dew point is 17°C, at 35°C / 50% already at about 23°C. That means at 35°C / 50% if you cool down to 24°C you have a very, very high humidity (~90%). That is why I combine the air/water heat pump (with integrated cooling function) with a brine preheating/cooling coil of the ventilation system. If the air is cooled from 35°C/50% to 17°C and then heated again to 23°C in the exhaust air, I am at about 55% relative humidity. And could theoretically also have 22°C floor temperature, so that I stay far away from condensation (17°C) and don’t have cold floors either. So, just recalculated: with these condition changes and 180m³/h - 207kg/h and an enthalpy change of 32.9 I come to about 6.8kW cooling capacity (just from the ventilation), which would already be pretty good. Only the geothermal heat exchanger has to be designed accordingly to manage this continuously (temperature spread + flow rate, etc.). But as long as you cannot "dry" the air, in my opinion it is pointless to make large investments in the cooling (because then it is somewhat cooler, but extremely humid).

If you express yourself publicly here, you have to expect headwinds, even if uncomfortable! ;-)
v.g.

I've already had the wind. Your onslaught therefore fizzles out and just gets on my nerves. That's why I said it beforehand, so the priests and preachers look for other victims. But the godlike € cares about the "external effect" – because he believes he has to protect "his" little sheep. I rather believe that it's all self-authority and extremely annoying. So sorry, but no more answers to your sermon from me.

I made a calculation for my case: I have an average U-value of 0.17 with 465m² surface area and a temperature difference of let's say 10°C (24°C -- 34°C) resulting in about 790W of thermal heating power. BUT:...

From here I couldn’t follow anymore but I laughed heartily. That’s what I call thorough thinking. :cool: The question is, what do you want to achieve? For example, I do not plan to keep the whole house at 20°C when it is 40°C in the shade. Our goal is to keep the bedroom at 24°C at night when it is, for example, 28°C.

um, where do you live that it’s 28°C at night? If your goal is to have only slight cooling, I’d put it this way: if you have the function and the two circulation pumps (1x brine + 1x underfloor heating) produce less waste heat than the cooling effect you have, it’s still better than without passive cooling – even if it’s still warm, 26°C is better than 28°C. That you will get down to a (supposedly) optimal sleeping room temperature of 18°C will not work. If you don’t care about the few € of electricity per year, why not – your sleep will thank you.

And to return to your question: I told you at the beginning anyway that the heating circuit distributor normally has ball valves on it, and you can simply turn them off (to what extent that affects the others would have to be checked separately in that case).

€ is basically not wrong with his statements, only in my example you quickly see, if you get to the bottom of it, that it’s no longer so simple to prepare the whole thing in a way that is understandable for the average consumer (Mollier h-x diagram, “simple” thermal calculations.....). And my calculation was definitely simplified :) no energies taken into account concerning the heating of components etc.

Well, the fact is that with this cooling function you can hardly achieve more than a 1-2 degree difference... so the desired effect will not occur without proper cooling...

But to get to your initial question, yes, you can shut off individual rooms and practically concentrate all the cooling on one room...

Well, the fact is that with this cooling function you can hardly achieve more than a 1-2 degree difference... so the desired effect will be absent without proper cooling...

Correct, the 1..2 K are experiences from the past (dew point temperature), without knowledge of the respective individual boundary conditions. For the summer load case, comparable analogous conditions apply as for the winter load case (heating). If the cooling load is low, passive possibilities (building construction) or indirect cooling can certainly be sufficient. At higher cooling loads, the use of technical refrigeration cannot be avoided. The latter can, with demand-oriented, holistic planning/dimensioning, certainly be avoided. Studies from Switzerland have confirmed the trend: heating degree days decrease while cooling degree days increase. The summer load case is rather neglected by the Energy Saving Ordinance, as the heating operation is primarily focused on in terms of primary energy. This is certainly due to the fact that heating degree days > cooling degree days. However, the Energy Saving Ordinance refers to a standard location that does not allow conclusions about the actual location. Therefore, it is not permitted to use final results from the Energy Saving Ordinance or KfW proofs for heating or cooling system dimensioning or consumption statements! Particularly affected are 1.5 g. construction methods with exposed locations and orientation of roof surfaces. Expecting a noticeable or sustainable cooling effect from a controlled residential ventilation is almost hopeless! I myself have conducted practical measurements on this. Temperatures of ~90°C are reached on the roof surface here, above a ventilated insulation layer ~65°C and more. It takes little imagination to understand how "effective" such a heating surface is in summer! ;-) Best regards