DISTANCE HEATING

FROM YESTERDAY TO TODAY

Distance heating in the Greater Lausanne area developed from  the Pierre-de-Plan plant. Initially dedicated to the production of town gas for public lighting, it was converted in 1934 into a single boiler house for the buildings of the nearby hospital, now the CHUV. 

Throughout its history, the network has benefited from technological innovations and its production facilities have evolved.In addition to a gas turbine, boilers were installed to support the needs of the heating network.Coal-fired boilers were replaced from 1965 onwards to produce directly at the distribution temperature, which was then 180ºC. Supplemental electric boilers were also abandoned, in favor of gas- or oil-fired boilers.

Since winter 2006, the Tridel plant has replaced the former household waste incineration plant, producing 220 GWh of heat compared with 80 GWh previously. This transformation has tipped CAD into an era where fossil fuels are no longer the main source of supply. Various production stations have also been added to the network, including a sewage sludge combustion station at the STEP de Vidy.

After decades of expansion,  the Greater Lausanne DAC has more than 1,300 connected buildings and over 100 km of network.

In order to promote development in the western part of the conurbation, CADouest SA was created in 2011, with the mission of promoting district heating, and taking charge of network extension work.

OPERATING PRINCIPLE OF CAD

Heat is produced by several industrial-scale production units serving a network of consumers. The heat is distributed throughout the city via an underground network of high-temperature pipes, supplying the connected buildings. The superheated water circulating in the pipes is used to heat the secondary network internal to each connected building, via a heat exchanger.  The water thus cooled by the heat transfer returns to the power plant to be raised in temperature again.