Cooling in summer with air-to-water heat pump, underfloor heating and/or ventilation system?

Hello,

currently, the installation of an air-to-water heat pump, underfloor heating, and a ventilation system from PLUGGIT is planned for our single-family house.

Now, fortunately, the temperatures are rising, and in our current old building, it is already getting quite warm. Of course, the single-family house will (hopefully) be better insulated, and naturally, proper shading will be provided, but nevertheless, it could still get very warm in the summer due to the large glass surfaces.

We are now considering whether we should provide air conditioning after all; there seem to be various options:

a) Installation of a different reversible air-to-water heat pump; cooling would then be done via the underfloor heating; how much cooling can be achieved this way is not entirely clear to me, and a dew point monitor is probably mandatory
b) Installation of the ventilation system with a ground source heat pump to supply cooler intake air
c) "Pre-switching" a real air conditioning system in front of the ventilation system?
d) Installation of a "real" air conditioning system including fan coil units

d) is ruled out for cost reasons; do a), b), or c) have any value and can be acquired for a "small" amount of extra money; a) and b) seem the most practical...

Regarding b), Pluggit also offers corresponding solutions (products: SWT180 and GTC); no idea how expensive/efficient.

Regarding a), Stiebel probably offers appropriate solutions; no idea how expensive/efficient; here there are mainly concerns that you only get a "cold lake" on the floor, but the room does not generally become cooler?

Opinions?

Thanks.

Passive cooling works and has low operating costs. However, it is of course not an air conditioner. Cold pools on the floor are undeniable, but through ventilation you have convection in the room anyway. I experienced it at friends' and it works. Geothermal exchanger for central ventilation system is also a good thing. Each of these options costs from €3,000 upwards.

But be careful with b) what kind of solution it is. There are different variants. One uses a real brine heat exchanger, the other only leads the supply air through a long underground pipe, which can lead to contamination due to condensate. Remember to decide that early so that the brine pipe can be laid right away while the pit is still open - saves earthworks. If at all, I would opt for the brine solution. But I haven’t fully made up my mind about that yet.

It seems that we at least agree that it should rather be towards a) active cooling via reversible air-water heat pump and underfloor heating or b) passive cooling using a geothermal heat exchanger through the ventilation system; c) or d) are probably really out of the question.

Could a) also be equipped with a geothermal heat exchanger instead of active cooling? Presumably not with a pure air-water heat pump but only with a brine system, right?

The question is which of the two is better or whether one can and should even combine both?

Could a) also be equipped with a geothermal exchanger instead of active cooling? Presumably not with a pure air-water heat pump but only with a brine one, right?

Good question, I don't know. With a brine-water heat pump, you automatically get the geothermal exchanger due to the system. Accordingly, the cooling function is also more powerful compared to that of an air-water heat pump. Whether that is noticeable, I don't know. I am also currently pondering whether to forgo the cooling function in the air-water heat pump and invest the cost savings in the brine heat exchanger of the controlled residential ventilation. The advantage of the controlled residential ventilation solution is not only cooling the outside air in summer but also pre-conditioning that same air in winter, which can make a preheating coil unnecessary. Maybe someone with experience can say which solution cools "better" if you are faced with a choice between an air-water heat pump with a cooling function or controlled residential ventilation with a geothermal exchanger.

Just check the cooling capacity of both systems. I have already deselected the preheater for controlled residential ventilation anyway, according to reports it never actually switches on and with enthalpy the system apparently continues to operate at even lower temperatures. In addition, it is available as an accessory and easy to retrofit.