In September Nantes Métropole Habitat (NMH), the public housing office in the city of Nantes, inaugurated the “Symbiose” project. The target? Making a 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 heats the air inside it, and the air generated will be used to heat the building water. According to the explanations of Luc Stephan, director of innovation at NMH, the heat from the greenhouse is extracted and then 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 other. 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 benefits of the greenhouse, especially in terms of savings. According to Mr. Mohamed Guirassy, in fact, the production of hot water by the plant has allowed him a saving which, brought on an annual basis, is about 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 the production of hot water, but also benefits the horticulture on the roof of the building. He knows something about it Simon Prevost, an organic horticulturist who is helping residents become familiar with the urban agriculture of this project. Cabbage and peppers are already finding a place in the boxes (strictly wooden), favored by the "well exposed" position of the greenhouse.
Also this winter, favored by its rooftop "nest", the building's population will also see free vegetables. Social housing, when "popular" still means something good for everyone, we want it in all possible futures.