A pilot project in the french capital is using sewage waste-water heat to warm a nearby primary school and in a later stage, along with others, the Presidential palace. The city of Paris wants green sources to fuel 30% of its energy needs by 2020. The new heating project, which is a collaboration between the city’s water department and two other companies, is the city’s first using power from the sewers.
The energy that goes into heating water for dishwashers, washing machines, showers and sinks usually goes to waste, but now it will be recovered. A steel plate is installed in the pipes where the sewage flows fast enough to maintain a constant temperature. The steel plate comes in contact with the waste-water and has a series of pipes through which a coolant ciruclates. The fluid is directed to a heat pump that concentrates the heat as high a temperature as 60 degrees Celsius.That heat is transmitted through the school’s HVAC system, which will heat the rooms.
The harnessed heat can only be used within 200 metres (656 ft) of its source – making it impractical for city districts lying far away from the sewage network. This means in theory 10% of Paris could be heated in this manner. The city plans to implement the system in additional schools, government buildings, and eventually; the Élysée Palace – the Presidential home.
The technique requires no combustion and it’s said that only the heat is recovered from the sewer water, not the smell.
Read more: The Montreal Gazette