In September Nantes Métropole Habitat (NMH), the public office for public housing in the city of Nantes inaugurated the “Symbiose” project. The target? Make one greenhouse on the roof of a 70s building to produce heat and cover the residents' hot water needs. Two months after the inauguration the balance is very positive: vegetables all year round and savings on hot water.
How is it possible? Where does the hot water for the building come from?
The principle is very simple. The institute installs the greenhouse on the roof of the building. The sun's heat warms the air inside, and the air generated will be used to heat the building's water. According to the explanations of Luc Stephan, director of innovation at NMH, heat from the greenhouse is extracted and stored in a large water tank located on the ground floor of the building. The hot water obtained will be used by the tenants for their shower, their dishes or anything else. The project aspires to cover up to 80% of the building's needs.
A visible saving of money on the bill
Interviewed from French TV TF1, a resident praised the advantages of the greenhouse, especially in terms of savings. According to Mr. Mohamed Guirassy, in fact, the production of hot water by the system has allowed him to save which, taken on an annual basis, is around 200 euros. Small economic hand, better sustainability and… let's not forget the vegetables.
The heat produced by the greenhouse is not only used for hot water production, but also benefits the horticulture on the building's roof. He knows something about it Simon Prevost, an organic horticulturist who is helping residents become familiar with the urban farming of this project. Cabbages and peppers are already finding room in the boxes (strictly made of wood), favored by the "well exposed" position of the greenhouse.
Also this winter, supported by its "nest" on the roof, the population of the building will also see free vegetables. Social housing, when "popular" still means something good for everyone, we want it in all possible futures.
