Garald

Right, but what would it ever be a part of? It wouldn't be a part of the PIV system, and I don't think it would be part of the smell extractor in the kitchen, would it? Perhaps that tube goes all the way to the laundry room, where there is an unnecessary extractor fan that is on all the time? >And that tape is not good. Shoddy workmanship I take? What should they have used instead?

I take “micro-onduleurs” means the same as “micro-inverters”? See page 5 in the attached file. An app on my phone shows me how much the panels are producing, but it doesn’t yet show how much I am using. devis_DEV-28851_28851.pdf

Here are some more pictures. Is this enough? This panel is next to the main panel (and connected to it). Not sure I can show much more without wrecking things.

The renovation was done by jacks-of-all-trades who did a decent job. Now, little by little, I am getting to know specialised tradesmen who do a good job for fair prices. Haven’t found an electrician or ventilation guy who fits that description yet. (The people who did the renovation have just told me they‘ll confer tomorrow and give me some sort of answer, though.)

Oh, I post here in part because the French building forum I know is full of rude people who don‘t know anything. Maybe things are now clear from the pictures - should I take photos of anything else?

More pictures.

Sorry if I came off as rude - certainly not my intention! Here are some pictures. The cables from the new electrical board inside to the panels on the roof are contained in the grey tube you see on the outside, parallel to the black cables that connect the house to the grid (and to my neighbours‘ building, in a bizarre aerial installation).

Maybe that's the case.

Well, obviously, but I need another connection so that I can sell excess electricity to the town.

Hm, trying to crop out the bit of the screenshot that describes my cat's behavior. It seems one cannot edit posts that are more than a few minutes old...

Connected to the city grid. Supposedly the panels are connected both (a) directly to my house and (b) to the grid. I've written to the company to confirm.

Wait, this doesn't agree with what I've been told. My understanding is that I will be consuming whatever energy this produces until it's connected. (This is France, in case it isn't obvious from the picture; is it different in the UK?)

Is this something I can do myself, or should I call a technician? Also, I take this is connected to the kitchen extractor (which I barely ever turn on) rather than to the PIV?

I returned from travel to be greeted by a strange trac-trac-trac ventilation noise (even though I had set the PIV to a minimum). It seems to come not from the main PIV unit as such, but from this duct going next to it: (Yes, both the PIV unit and this are above a kitchenette‘s false ceiling.) What is this? Whom to call? What is the issue likely to be?

Just got 3kW worth of solar panels installed; no battery. The power-grid monopolistic company will hook me up to the grid when it pleases (maybe in a few days, maybe in many months). In the meantime, how do I set up things (meaning mainly my heat-pump, water-heater included) so that it actually uses the power produced by the panels (functioning when there's sun out, that is, rather than waiting for the water to get cold first)?

Yes, I think so. The general contractor says the existing ducts (which carry the positive-pressure air from the PIV to the first and second floors) are too narrow for conventional MVHR. Hence my interest in cascade MVHR. Cool, thanks. Do they also install things (in France) or would I have to work with a local plumber or ventilation person?

Pretty much what says on the headline. Situation: I have part of the ground floor, all of the first floor, and all of the attic for a total of about 175m^2, or 120m^2 counting only the surface in which one can stand (the rest is the sides of the attic, or staircases, which don't count for the official total either). I suppose I'd need three cascade systems, or two if I'm very lucky (since I have only a bit of the ground floor, and the staircase is quite large). (Currently I have PIV, which I am not very happy with; it hasn't even been installed all that well - it's nearly impossible to change the filter without destroying it.)

ERST20D-VM6D PAC-ISOCH MITSUBISHI UE ECODAN SPLIT ZUBADAN SILENCE 12KW 1PH R32 ZUBADAN SILENCE Won’t they just cool a thin layer of air at the bottom? Will have it, don’t have it yet.

The model doesn’t. Mitsubishi models that could used an older, more polluting cooling fluid - and all installers I talked to expressed profound skepticism as to whether producing cold water was ever useful, particularly without underfloor heating (I have radiators).

Well, obviously, the humidity will go up, but the temperature should go down. If by "cooling" you mean lowering the heat, then yes, obviously and tautologically. If by "cooling" you mean lowering the temperature, no, not necessarily. Without refrigerative means, the wet-bulb temperature will not go down, but the temperature may and in fact should be lowered as humidity is added, no? >Something your ASHP is likely capable of doing? Nah, it's not reversible. (It's air-water; if it had a different, more polluting refrigerant coolant, it could produce cold water).

I'm still trying to figure out how to make my attic comfortable during heat waves. I live in the Paris area, where heat waves are comparatively dry (in fact, they are the only time when it is comparatively dry). So, I decided to get a medium-sized evaporative cooler: https://www.amazon.fr/KLARSTEIN-Skyscraper-Rafraîchisseur-Humidificateur-Refroidisseur/dp/B085HM8N2Z?th=1 It does produce a cool breeze, so I suppose it is helpful if you stand or sit literally in front of it and quite close to it. I didn't notice enough of an effect if sitting at 1-2m from it. So, wanting to determine the truth, I ran an experiment. My attic consists of two compartments (not counting the bathroom): I closed the windows in both, and ran an evaporative cooler (Klarstein Skyscraper ICE) in one of them; I put a thermometer/hygrometer in each compartment. After a while, - the half without the cooler was at 30.9 C, 50% humidity, - the half with the cooler was at 30.9 C, 60% humidity. That's a remarkably total and precise failure! The cooler was humidifying without cooling. My question is: how is this even possible? Wouldn't a simple decorative indoor fountain do better than this? How can a tool manage to be so bad? How do you set out to make an evaporative cooler that doesn't work? (Some data (from https://www.kwangu.com/work/psychrometric.htm😞 30.9 C at 50% corresponds to a wet-bulb temperature of just 22.75 C (i.e., we could be very comfortable if were just willing to do math while wrapped in wet towels). An evaporative cooler that keeps enthalpy constant (I thought that was a reasonable assumption - these are low-powered devices, so the heat they dissipate by operating is likely negligible) would keep wet-bulb temperature constant. Then, at 60% humidity, we would have expected the temperature to be lowered to 28.7C, a significant change.) I ran the experiment again the following day. Starting conditions (at 4:50pm): outside temperature 28C, attic room with cooler: 32.8C, 42% humidity; attic room without cooler, 32.9C, 47% humidity. End conditions (at 11:25: attic room with cooler - 30.3C, 60%, attic room without cooler - 31.2C, 51%). All right, this time, the cooler did *something*, but it seems to be remarkably bad at what it does.

Well, I hope that this is the one and only renovation I will do in my life, so any knowledge I acquire is useless to me *except* for academic knowledge (which is a nice way to review undergraduate physics, learn what our friends in finite element analysis do after all, etc.).

If you wish, but where do I read up about these models?

Well, can you tell me where to look up those models (and the physical reasoning behind them)?