Where the project comes from
Every building receives the sun. Almost none of them use it.
Kelveen starts from a simple observation: on an older building, the window is at once the weakest point and the one place where energy arrives free of charge. We put up with it, for lack of a way to govern it.
Why the façade, and nothing else.
The window is the weak point.
That is where heat gets in during summer and escapes in winter. In a pre-1990 building it is usually the least well handled element, and the most expensive to address any other way.
It is also the way in.
Sunlight arrives free of charge at exactly that point, every day of the year. The question is not how to block it, but when.
The existing stock is vast.
Most of the buildings of 2050 are already standing. They will not be replaced: the work has to happen on what is there, without emptying homes or touching the structure.
And nothing is proven yet.
Everything above is coherent, calculated, cross-checked against a second model. Nothing has been measured on an occupied building. That is precisely the work underway, and the reason this site exists.
The genesis
The idea came from three trades meeting.
Light and its effects first: understanding that a ray is not only heat, but a resource that can be aimed. Then solar energy, with objects left outdoors that must last years with nobody to maintain them. And finally the existing building stock, where everything turns on what is already standing. Kelveen is what those three subjects produce when you put them together in front of a window.
How Kelveen came about
From a hunch to a real building.
The solid line stops where the project actually is. The rest stays dotted, and will until it is done.
Protéger l’invention
Le mémoire de brevet est en finalisation.
Who carries the project
One person, for now.
Paul Trément, R&D engineer in Bordeaux. Twelve years spent designing objects that live outdoors — embedded electronics, solar energy, light — and a company carried from idea through to its sale.
That first time is where the order Kelveen follows comes from: protect the invention, measure, and only then promise anything to anyone. A validated product is not enough to keep a company standing.
Where the project stands, unrounded.
Four lines rather than a speech. Two are settled, two are not.
- The energy model exists.Albedo compares a building with and without Kelveen, hour by hour across a year, cross-checked against a second simulation tool.
- The test rig is being built.It is what will bring the model up against real materials. Until it runs, the results remain calculations.
- The patent is filed.Application lodged with the INPI on 15 August 2026. Priority is secured; examination will take however long it takes.
- No building is fitted.Not one, to date. Finding the first pilot site is the step that matters most, and the one where you can make a difference.