I can’t see anything ‘cos we don’t subscribe to Facebook (or any other media like it) so what is impressive please @Corona ?
Well Facebook isn’t 
Sorry, hopefully you can read this one.
‘Kind of miracle solution’: How Paris is harnessing the Seine to replace air-con | Extreme heat | The Guardian ‘Kind of miracle solution’: How Paris is harnessing the Seine to replace air-con | Extreme heat | The Guardian
Currently working on a project for our Mairie not to dissimilar but on a lesser scale, most of the houses in the village have cellars some have as many as 6 at different levels.
This came about because I have the intention to install a couple of fans in our cellar to push the cooler air into our living room and kitchen via the air duct for the wood burner and the 2 soupirails for natural air conditioning. Mrs W. is on the town council mentioned this during a meeting concerning the heat wave and the Maire said great idea, ask Mr W to draft plans and methods of installation.
Nice one! Please keep us informed. I posted on another thread the other day about the earth air tubes and a chap who unfortunately brought in mold spores. Another engineer swapped to using a sealed system filled with water (4x the heat transfer of air) meaning smaller pipes could be used. Water into fan coil units for cooling.
If you have any data please share as this project will be posted by the Mairie to the community and may make the news on France 3 etc. I haven’t got to filtration yet any advice is appreciated I love working with fellow engineers.
You’d need to duct the hot air from the cellar cooling radiator to the outside world or you’ll heat up the cellar.
And insulate the water pipes between the two radiators which could be fed through the fireplace’s air intake.
Yes of course simple thermo dynamics, the system isn’t pérenne just a simple solution during heat waves. Most of the houses have cisterns with stone canals another source of cooling
@NotALot sorry I didn’t read correctly I aimed my last post at you
Such a system might not need a warm air vent, depending on the thermal capacity of the cisterns, and venting warmed air out would mean pulling warm air in from outside. If the system begins to be complicated then it may be easier to just buy ready made Aircon.
Most of the cellars have natural ventilation as they were used for storage some of the larger ones have steps leading into them from the road or courtyard,I know of a couple that have lavoirs fed by the cistern system, pas bête les ingénieurs médiéval 
I’m looking into cooling one or two rooms on the first elevation not the whole house. Keeping peeps safe during heat waves, Hot always goes to cold so just a question of how low the duckting needs to go down, if it’s needed. I’ll have to include guidance on how to use whence installed, like not to be used permanently 24/24, use natural ventilation when the outside temperature drops etc. De type, ventilation pour les nulls 
use It as a thermal battery refresher
Your project sounds like a great idea. Do you have a wooden floor over the top of the cellar ?
I’m wondering whether the concept could be achieved cheaply by using the type of flexible ducting one might use for a tumble dryer exhaust with the type of low wattage electric (in-line) fan that can be installed in a lengthy bathroom extract fan tube.
Suspending the fan unit on wires from the underside of the floor may help reduce noise and vibration transmission when the fan is running.
A simple floor vent could be covered in winter to prevent the ingress of cold air.
I’d be most interested to see your plans once drawn up. Thanks.