Heating of the supply air in the pipe

Hello,

We have built a passive house and moved in around Easter. Unfortunately, we had an almost unbearable summer. Despite shading, we had almost continuously over 26 degrees in the house, even at night. We have a ventilation system from Paul (Novus 450) with an active brine air precooling. The ventilation is not yet properly adjusted; it currently runs at about 30% higher volume flow than necessary. The problem now is that no matter what the temperature of the supply air is, about 0.5 degrees less than the room temperature arrives at the valves. Even with active bypass and a lowering of the supply air to 16 degrees, we have 22.9 degrees (our current room temperature without additional heating is 23.5 degrees). The installer measured the values and said not optimal but within limits. However, I cannot believe that since we sweat night after night and don't even get cool air into the house at night? Has anyone had a similar experience? Thanks for any help...

Regards,

Thorsten

Can't you just open the windows now that it's cool? Or did you save that? Otherwise, without air conditioning in summer, it's simply so that after a while it gets warm inside, no matter how well insulated it is. Only with good insulation does the heat not escape so quickly again. We also only have a Kfw70 house / Energy Saving Ordinance 2009 and so far without heating still pleasant room temperature. A real passive house is designed to be heated from the normal internal sources, so it probably won't get cold that quickly. The only idea I have would be to check if you only have high humidity, that makes dormitories more uncomfortable. For us, it was also relatively high in the first year because a lot still comes out of screed, plaster, etc. But after the first winter, it was better.

Good morning,

We can and have also opened the windows, that is not the problem. The issue is that air close to room temperature is always being blown in because the supply air flow warms up in the duct. Even when I turn on the bypass and cool it down to 16 degrees, nothing cool comes out. I could have saved myself the more expensive system with the heat exchanger if it worked with just a few pipes. We have also checked the temperature at the distributor in the utility room behind the ventilation system; it is slightly above the outside temperature, so the bypass is working.

What experiences have you had with such systems? Actually, the warming should only be around 1-2 degrees.

The warming in the pipes is not as high for me. The pipe lengths are at most around 15m for me, but most of the distance is on the all-sided insulated, but unheated attic (which is usually below room temperature anyway). From there, it goes down into the rooms within the insulated envelope. However, the storage mass of screed, plaster, etc. is so high that even a bit of air with bypass does not cool the house down. That’s also logical; just look at the heat capacity of air per cubic meter. I can well imagine that the air in longer pipes warms up if they lie within the warm envelope.

yes, the pipes definitely heat up in advance, but that is also the case with other people and would have been read about more often. What kind of active cooling are you using? There is nothing to be seen on the manufacturer's page. There are only geothermal heat exchangers. Without the interjection "active cooling," I would have said colloquially, bypass defective or outside temperature high

Hmm I see no problem, everything works as it should. The controlled residential ventilation is not for cooling but for ventilating, no matter what the seller told you...