Situated in the heart of an area presently under renovation, the structure, which was built in 1936, has not been used  by the Syndicat des Eaux d’Ile de France in the past 5 years.

It is in this context, at the end of 2008, that Elioth replied to the Call for Ideas competition launched by the town for sustainable valorisation of the building in proposing an original idea : transform this drinkable water tank into an urban cumulus to store solar thermal energy and use it in winter for  domestic heating.

Although an extremely simple concept, it is nontheless the first of its kind : with no existing support, the idea of overhead storage up until that point came up against the construction costs of such a tank and its load-bearing structure. All that had to be done was to install a hot water distribution system to supply the area’s main boiler plant room located at only 100 m from the water tower, and with temperature sensors the whole system would adjust automatically to the needs. In terms of efficiency and performance, the results of the analyses were most promising. By adding 500m² of solar captors associated to the water tower’s storage it is then possible to meet 2/3 of the needs in heating of 65 of the future houses in the area (low-energy houses) and to supply almost half of the needs in domestic hot water to over 200 other rehabilitated houses. Thanks to the quantity and compacity of the volume of water in the tank, a level of isolation equal to that of a new building is sufficient to maintain a temperature of 70°C in winter.



  • Ville : Montreuil-sous-Bois
  • Client : OPHM
  • Équipe : Elioth_lab
  • Prestation : Faisabilité