I fully agree with you.
The way I understand it, this concern sort of gets dismissed because you are simply not supposed to open a window in a passive building.
I myself have sort of given up on it. During heat waves life will be hard anyway, I’m not sure bricks will make that much of a difference.
But it should be a choice made by the group, which is why I insisted on a selection process.
Actually this is true for the winter but for the summer, aeration is actually part of how the heat gets regulated and how you avoid over-heating in a passive building…
Indeed, that’s the info we are missing…
To be honest, I personnally prefer bricks, but I just wanted to be able to make an informed decision rather than a purely esthetic one we might regret down the lane…
The way I understand it, this is also true in summer. Aeration will be automated, picking up fresh air at the ground level. But I’m not strong on anything technical, so I may have missed something.
@Sarah For what it is worth, i am definately not claiming to be an expert (but I have renovated a house to a low energy house, I have participated in ‘batiment exemplaires’ which demanded to write a dossier explaining all techniques/coherence between the different decisions taken, and as we didn’t hire an architect I took up that role, and thus following some trainings, talking to a large number of architects/technical engineers to be informed.This information gathering took about a year… But that dates from 2012, so I am definately not updated, allthough a lot of the techniques used are still used today).
what Serge told in the meeting (and what I understood from it): in periods of heatwaves:
switch off your ventilation during the day. It’s the ventilation that takes care of the aeration when your windows are closed, but if you do it during a limited time, this should be ok i guess. The ventilation will have a ‘recupération de chaleur’. In winter the air from the inside that is expelled is warm, and this warmth is used to warm up the air coming from outside, which is cold. My understanding is that in summer this inverses: meaning: the colder air inside is used to cool down the air brought in from outside. However, my understanding is that this latter (during summer) has little to no effect, and so during heat waves, with the ventilation, you bring in the warm air from outside. This -for me- explains why Serge says ‘swittch off your ventilation during the day’.
switch on the cooling function during the night. In the note technique of Walk they mention ‘Ce système sera également capable d’évacuer la chaleur accumulée durant les journées estivales par le biais d’un night-cooling (fonctionnement de nuit).’ Serge also said to definately switch this on during the night in warm periods of the year.
what the architects/Walk also mentionned is overheating in passive buildings mainly comes from two things:
the windows (sun shining on the windows): this you can tackle with the solar protection. They told the different systems of solar protections can make a difference in the level of protection, but it’s not at this point of the project where they will dive deeper into this. Also to shut this protection right from when the sun comes up and not wait till you start feeling the warmth in your apartment.
the heat produced inside the apartment that is kept inside because you are in an insulated unit. This heat comes mainly from humans/human activity. The architects and Walk said it doesn’t really come from the machines, or the lighting (which will be Led). For me - personal experience- cooking hot meals should be avoided in those periods. We have two common spaces equiped with a kitchen that can be used for that purpose. That might heat up those spaces, but i think/guess they are less exposed than some other units (like yours), so maybe easier to cool down at night? Plus, the comfort is - i guess- mainly for a good sleeping during the night, and we won’t be sleeping in the common spaces (except for when we have guests in the guestroom).
the architects also mentioned that in their units, during heat waves the temperature never went above 24°C. The question is though: is their unit comparable to your unit. My experience, living in a low energy building, and that is the same experience I hear from Mieke (also living in a low energy building): during the day it’s really more comfortable to live in a low energy building than in a ‘normal one’ if you follow everything to keep the sun out and the heat production in your unit low. During the end of the day/at night, it’s really ok during heat waves (and i don’t have this cooling function of my ventilation). I have bricks (as a structure) which are covered by the insulation on the south-west side and bricks that are exposed to the exterior on the north-east side. So definately not the same configuration as your unit, nor is my house enclosed. You are always welcome to visit and experience it , during heatwaves or other moments, if you think this can be an added value.
I don’t think this gives much answer on your concern of the heat island effect, and I agree, what is written in the proposal is neither. For me, if you want a decent answer, you need to look for an expert on this , for me the architects are not an expert on this matter.