ᐅ Ventilation system in summer?

Hi,

Alex85 schrieb:
Enthalpy heat exchangers not only transfer moisture but also limit it.

We have those. However, it only works if you also reach the dew points of the water vapor. If you don’t cool the air enough for condensation to occur, the moisture simply remains in the supplied air and is drawn into the house.

In winter, it can effectively act as a humidifier for the dry, cold incoming air.

Such a unit cannot bypass the laws of physics.

Best regards,

Andreas

tempic schrieb:
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 low airflow rates. Otherwise, the "storage" does not have enough thermal capacity according to calculations. The datasheet mentions a cycle change every 70 seconds, which likely would not work under normal conditions. In the detailed datasheet, only 75% is stated, along with the measurement method (according to the Ecodesign Directive).

andimann schrieb:
Ha, yesterday it was 20.5°C (69°F) supply air temperature outside at 30°C (86°F).

Ground heat exchanger rules....

SCNR

...

I have a few questions:
What is the airflow volume?
Is the basement connected to the ventilation system?
How many cubic meters are being ventilated?
What are the diameter and length of the ground heat exchanger?
How deep is it buried?

At what airflow volume?
About 240 cubic meters per hour (cbm/h).
Is the basement connected to the ventilation system?
Of course.
How many cubic meters are ventilated?
About 670 or 680 cubic meters.
Diameter and length of the ground heat exchanger?
KG 2000 pipe with DN 200. Just over 30 meters (about 100 feet) long.
How deep is it buried?
It comes out of the basement wall at about 180 centimeters (6 feet) below the turf line and then rises with a slope of about 1.5%. It should end up at around 135 centimeters (4.4 feet) below the turf line.

Regards,

Andreas

Try reducing your airflow slightly to increase the residence time in the ground heat exchanger and check if your bypass is open. For ground heat exchangers, you can set it manually to "Open" for the entire summer instead of automatic.

Yesterday, my supply air was at 17°C (63°F) and exhaust air at 24°C (75°F) with an airflow of 175 m³/h (103 CFM) or more.
I have two parallel pipes, each just under 30 meters (98 feet) long, DN200 (approximately 8 inches) running from about 1 meter (3 feet) below the garage to over 2 meters (6.5 feet) deep in the hillside.

Payday schrieb:
Rather, one should ensure that the interior of the house does not warm up in the first place.

For example, by cooling the incoming fresh air with the outgoing exhaust air.

Alex85 schrieb:
Vaillant recoVAIR up to 98% (wow!)

We have it, but of course, I haven’t verified this myself. Where does that figure come from and what does it mean? In my documents, I find a thermal efficiency of 85%, 81%, 83%, or 80% (depending on the model).

Mycraft schrieb:
Which isn’t much cooler and the house still heats up... After a week of 30°C (86°F) outside, inside temperatures approach outside temperatures as well.

No, because we haven’t had a week of 30°C (86°F) here yet (so far). Also, at night it is cooler inside than outside.

andimann schrieb:
If you don’t cool the air enough to cause condensation, the water simply remains in the supplied air and is drawn into the house.

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