District Heating
The heat produced in a cogeneration or waste-to-energy plant can be used for district heating, a form of heating by which thermal energy (water super-heated to a temperature between 90 °C and 120 °C) is distributed, through pipes, to connected buildings. On reaching its destination, the water, by means of a heat exchanger, releases its heat to the building's heating system in order to heat homes or offices and, in some cases, to supply hot water. The water then returns to the power station to recover more heat and to repeat its journey. This system contributes to improving air quality by eliminating the individual boiler of each building served.
A further evolution of cogeneration is trigeneration, which not only simultaneously produces electricity and heat, but which also allows for the use of thermal energy to obtain cooled water by means of absorption refrigeration systems. For this purpose, heat can be distributed via the district heating network, and converted into air conditioning on the spot, or the “cold” can be generated centrally and supplied to users via a specific distribution network.
