District heating is a method of heating where heat is generated at a centralized location and delivered remotely to customers in the district. This method of heating is very common in Europe and is among the most energy-efficient means of generating heat. It is also a very old method of providing heat and or hot water, having been used since ancient Roman times. And while common in Europe, there are places in the US where district heating has been in use for over 100 years.
How District Heating Works
First, heat has to be generated. With district heating, this can be done any number of ways, from coal to geothermal to nuclear. In a lot of areas where district heating is common, geothermal and plants that burn biomass are common. These plants can often exceed 100% efficiency and are an environmentally friendly way of generating heat.
Whether water is heated by burning fossil fuels, from nuclear reactions, or from geothermal energy, it is turned into super-heated steam. That super-heated steam can then be used to generate power, or piped directly to the customer for use. If it is used to generate power, the plant will be known as a ‘co-generation plant’, producing both power and super-heated steam. There are plants that use oils for their power and heat generating needs but these are less common due to their higher operating costs and possibility of polluting the area if a leak occurs.
Once the super-heated steam is ready to be distributed, it is sent to insulated pipes that run to the customers home or building. The steam can then be sent into radiators in the building and can be used to heat water via a heat exchanger. Hot water can also be obtained directly from the generating plant or by turning the steam into hot water, depending on the setup of the generating plant and customer setup.
This method of heating isn’t terribly common in the US due to population densities and urban sprawl. It becomes more efficient to generate heat on-site in most areas rather than in a centralized location. However, in some US cities district heating has been supplying reliable heat and power for many years.
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