The origins of district heating

The emergence of the world's first heating system was initiated by Nature, which supplied a ready-made heating medium – water from a geothermal spring. In Chaudes-Aigues, a small town in the region of Cantal, France, hot water with a temperature of 82 °C from a spring delivering approximately 300 litres per minute was used for heating households and churches as early as the 14th century. This is a known fact since documents from 1332 mentioning that two villagers fell behind with the payment of heat bills have been preserved in archives.

 

The idea of district heating in cities emerged much later, the resourcefulness and ingenuity of the inhabitants who created a system of wooden pipelines distributing water throughout the village must be appreciated. The idea of district heating in cities emerged much later, the resourcefulness and ingenuity of the inhabitants who created a system of wooden pipelines distributing water throughout the village must be appreciated. The first large-scale commercial heating system was built in the United States of America in Lockport, New York. Its creator, Birdsall Holly, an engineer and inventor, was second to Edison in terms of the number of patents filed. In 1876 he tested central heating in his own garden in Lockport. One year later he set up the Holly Steam Combination Company and started supplying heat to the city centre. A few years later the district heating network in Lockport was over 4.8 km and had 65 household connected.

 

In 1881 in a number of major US cities – for example in New York – central heating tests involving steam commenced. At that time Birdsall Holly filed a dozen or so patent applications describing solutions for respective elements of heating systems such as heat-pipes, meters and pressure regulators. The first heating station in New York was situated in Manhattan at Cortland Street and with its ca. 68 m tall chimneys it was the highest building in the district. The structure of the plant was quite unique – 48 boilers of 250 horsepower each (ca. 186.5 kW) were installed on three levels. Also, a 3-mile (4.8 km) long heat- -pipe insulated with mineral wool was built. The first customers buying heat from New York Steam Company (NYSC) were new office buildings, e.g. the First National Bank on the corner of Broadway and Wall Street, connected to district heating in March 1882.

 

 

Four years later NYSC built another boiler plant supplying heat to the city centre, a luxury district where, among other VIPs, John D. Rockefeller resided. He wrote to the New York Steam Company: I have had my house heated for several years by steam supplied by your company and am satisfied with the services given. This testimony was used as grounds for an advertising campaign aiming to convince the inhabitants that district heating was deemed comfortable by demanding upper-class customers. The development of a centralized system of heating in New York, Chicago and other American cities points to a correlation between new technology and the emerging urban planning trends in the early 20th century. Taking the burden to design chimneys for every new building and taking into account the limitations imposed by technological requirements of previously used types of heating off the architects enabled skyscraper cities to develop.

 

This is clearly illustrated by a press advertisement of the New York Steam Company from 1930 with the main slogan: Serving a City of Towers. The effectiveness of district heating in modern cities was finally substantiated by constructing the Empire State Building. In 1931 the building housed more than 100 stores, and had 7,000 radiators installed to heat 21,089 sq m. The first five storeys of the skyscraper were supplied with heat from the substation in the basement and on the 29th floor there was a pumping station from which heat was supplied to floors 6 to 54, and the topmost part of the building was supplied from facilities on the 54th floor. In Europe Birdsall Holly's technology was first used in single institutions and representative new buildings such as the Technical University of Berlin (1884) or the Town Hall in Hamburg (1893) where heat was for the first time cogenerated with electricity.

 

District heating in European cities first developed in Dresden in 1900 with the main aim of reducing the fire hazard in the district of Zwinger and the royal palaces. Likewise in New York, a power plant produced steam for heating but water-based systems were already in use in buildings. In addition, in 1911 another plant was commissioned using excess steam to supply the water-based heating system in the city. In the first decades of the 20th century district heating systems developed very slowly. It is estimated that before the outbreak of World War II as many as 50 district heating systems were in use in the United States and about 100 operated in Europe. Hot water based solutions prevailed in Europe while in America steam systems predominated. In 1921 Fernheizwerk Hamburg GmbH commenced connecting the city to district heating. According to Abraham Margolis – their chief engineer – the key driving force of the project was the high price of coal in Germany after World War I. Similar solutions were soon introduced in Cologne (1922), Leipzig (1925) and Berlin (1925). District heating systems were also set up in other cities outside Germany – in Copenhagen, Utrecht, Paris and Zurich.

 

In Reykjavik the construction of a geothermal heating system started in 1930. It has been in operation to the present day, satisfying the city's requirement of heat for heating and the production of hot service water. In the then Union of Socialist Soviet Republics the concept of using cogeneration was included in the GOELRO electrification plan in 1920 in order to reduce the future requirement of fuel. Leningrad was the first city to commence heat supplies in 1923. In Moscow, in 1931, the company Teploset Mosenergo was established to manage the distribution of heat although heat supplies had started three years before. These early Soviet projects provided the basis for all future district heating systems in the Eastern Bloc in Central and Eastern Europe. They focused on reducing the amount of primary Energy supplied for the needs of electricity production making use of cogeneration.

 

After World War II in Europe district heating started developing intensively. Reconstruction of cities destroyed during the war and building new housing estates generated high requirements for heat which could be most effectively met by centralised systems only. In technology a clear trend to reduce the temperature of the heat medium dominated together with new solutions in insulation and pipe design to ensure a reduction in both losses and costs of construction and maintenance of district heating facilities. In 1948 Karlstad and Klagenfurt joined the group of cities with a central heat supply. Later, in 1951, in London, a district heating scheme was put into operation in the region of Pimlico, and in 1952 in Helsinki a centralised heat supply system was built.