Ventilation system in summer?

Hi,

Enthalpy heat exchangers not only retain moisture but also limit it.

We have them. But it only works if you actually reach the dew points of the water vapor. If you don’t cool the air down enough for water to condense, the water simply remains in the supplied air and is drawn into the house.

It can work properly in winter as a humidifier of the dry, cold supply air.

Such a device cannot trick physics either.

Best regards,

Andreas

Decentralized:
Viessmann Vitovent 100-D: 91%
Viessmann Vitovent 200-D: 90%
Ventomaxx V-heat recovery Rondo Plus / LAL: 90%
Lunos ....

That is at least surprising, what is stated in the brochure. I would be interested to know under which conditions this was measured. Physically, this probably only works with very small temperature differences between indoor and outdoor air and/or very small volume flows. Otherwise, the "storage" does not have enough heat capacity mathematically. The datasheet mentions a cycle change every 70s, which probably does not work under normal conditions. In the detailed datasheet, only 75% is mentioned, where the measurement method (according to the Ecodesign directive) is specified.

Nyah, yesterday here at 30° outside 20.5° supply air temperature.

Geothermal heat exchanger rulez....

SCNR

...

I have a few questions:
at what volume flow?
Is the basement also connected to the ventilation?
How many m³ are ventilated?
Diameter and length of the geothermal heat exchanger?
How deep is it buried?

at which flow rate?
about 240 cbm/h
Is the basement connected to the ventilation?
Of course.
How many m³ are ventilated?
about 670 or 680 cbm
Diameter and length of geothermal exchanger?
KG 2000 pipe in DN 200. a little more than 30 m long.
How deep is it buried?
comes out from the basement wall at about ground level minus 180 cm and then rises with about 1.5 % slope. should therefore be at about ground level minus 135 cm at the end.

Regards,

Andreas

Try to reduce your volume flow a bit so that the residence time in the ground heat exchanger is longer and check if your bypass is open. For ground heat exchangers, you can set it manually to "Open" for the whole summer instead of automatic.

Yesterday, my supply air was at 17°C and the exhaust air at 24°C at 175 m³/h and more volume.
I have 2x nearly 30m parallel DN200 between about 1m below the garage and over 2m deep in the slope.

rather, one should ensure that the interior of the house does not warm up in the first place.

For example, by cooling the fresh air against the exhaust air.

Vaillant recoVAIR up to 98% (wow!)

We have it, but of course I haven’t measured it myself. Where does the figure come from and what does it mean? In my documents, there is a heat provision rate of 85%, 81%, 83%, or 80% (depending on the model).

Which is not much cooler and the house still heats up... after a week of 30°C outside, the indoor temperatures also approach outdoor temperatures

No, because we haven’t had a week of 30 °C here (so far). Because at night it is colder than outside.

If you don’t cool the air enough for water to condense, the water simply remains in the supplied air and is drawn into the house.

The enthalpy exchanger, as I understand it, always balances the moisture between both sides (because it has a membrane that allows water vapor molecules to pass through). This should work like with heat in both directions (exhaust air-fresh air / fresh air-exhaust air), always from the side with higher vapor pressure to the side with the lower vapor pressure.