District heating has become the method of choice in many cities in Europe. It has also increased in popularity and usage in much of the rest of the world. This idea is actually over 100 years old. It started in 1903 in Moscow, Frederiksberg and Copenhagen, all in the same year.
District heating systems as a modern concept were designed and introduced in the 1980s (with steady developments ever since), with automatic control, remote monitoring and unmanned operations. The concept unites available heat sources that would otherwise be wasted for heating or cooling.
Many networks also use cogeneration or combined heat and power (CHP). Cogeneration is the production and use of electricity and heat simultaneously from a given energy source. The sources of cogeneration are usually: heat from waste incineration, waste from energy production, industrial waste and biofuel boilers. Solar and geothermal energy are renewable energy sources that are also harnessed. The market has been further developed through the conversion of natural gas into the district heating supply to customers.
A typical installation consists of a highly insulated “heat main” of flow and return pipes that distribute hot water (or steam) not to all the buildings it is connected to. A junction point allows easy connection to each building, from where hot water can be taken from the main pipe to a heat exchanger (heat substation) within each building. The heating circuit inside the building is thus isolated from the heating network.
Flow and return line temperature measurements, plus a flow meter (which together form a heat meter), allow actual usage within each building, or even apartment, to be separately metered, delivered, and billed consequently. Remote meter reading via a modern and secure web interface or drive-by is generally possible, as is remote diagnostics to ensure reliable operation.
For any modern city with a dense population, this type of system offers the most significant contribution to ensuring energy efficiency that is readily available. District heating is used in many cities (especially in Europe), but more needs to be used in major cities around the world.
Situated directly on the Mid-Atlantic Ridge, Iceland is one of the most geothermal-active places in the world. The country experiences mild summers and often chilling winters. An environmentally friendly solution, taking advantage of the country’s geographic position while meeting the unique needs of residents and businesses coping with the often cold weather, makes sense.
The use of geothermal district heating in Iceland began almost 100 years ago. Over the past 84 years, the country and its citizens have worked diligently to perfect the system. The people and the government have made Iceland one of the world leaders in this. Iceland’s capital, Reykjavik, began in 1930 with a small elementary school and a children’s version of technology.
Today, the city provides heat for 95% of the more than 120,000 inhabitants with geothermal district heating. The remaining 5% is supplied by some traditional methods, as well as geothermal energy, giving home and business owners the option of electric heat and space heating.
Outside of Reykjavik, the use of geothermal district heating in Iceland is widespread. Almost 90% of the country’s heating and hot water is provided by geothermal heating, while oil, coal and other sources make up the remaining percentage; however, Iceland also uses geothermal energy for more than 50% of its energy source, some of which goes into electric heating systems.
