Street heating

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Heated sidewalk in winter in Holland, Michigan / USA
Installation of geothermal street heating in Reykjavík , Iceland
Installation of the MULTIBETON open space heating on 2 × 16,000 m² at Zurich-Kloten Airport in 1972

Street or lane heating is a technique used to keep entire streets or special street sections, such as steep slopes or bridges , permanently free of ice in winter . Street heating is powered by electricity or water that is heated with geothermal energy . The second variant also enables the street to be cooled in summer , whereby the thermal energy can be stored or otherwise used.

Street heating, like turf heating in sports facilities , is counted as open space heating .

Basic idea

In addition to economic and ecological principles, there are also demands on the safety of roads in favor of the permanent heating of roads in winter:

Roads are usually cleared of snow by the winter service and kept from freezing with road salt . The road salt, which is washed into the sewage water with melted snow and ice and onto forest and meadow areas adjacent to roads, represents a burden on the environment that can be reduced or avoided entirely with the use of street heating. The fact that a heated road section is tempered above freezing point (0 ° C ) when necessary  also prevents the formation of black ice , which leads to a significant increase in road safety. Another benefit is the increased service life of a heated road. Heating reduces maintenance costs, as frost damage can no longer occur; in particular, it significantly reduces the formation of potholes .

Technical implementation with geothermal energy

Street heating works practically the same as floor heating for apartments. In the asphalt, hose lines are laid in loops a few centimeters deep, through which a liquid heat carrier (e.g. water) circulates. Geothermal energy is used to heat the water, and this can be developed with several boreholes, mostly over 100 meters deep. The process can therefore be used particularly well in regions in which geothermal energy can be reached at a shallower depth. The advantage of this technology is that only the water pumps require electricity and the actual heating is done with renewable energy .

In Scandinavia, and especially in Iceland , street heating has long been common due to the geologically very easily accessible geothermal energy . For this purpose, wastewater is also fed into street heating systems in Iceland, as this still has sufficient residual heat at 30–40 ° C. So far, only a few pilot projects with geothermal energy have been carried out in Germany, but they are promising. In the Bavarian town of Marktredwitz , for example, a 135 m long street heating system was designed for a downhill section which, according to the plans, should have paid for itself after nine years due to the lower maintenance costs of the street .

Technical implementation with electricity

The operation of street heating with electricity is also possible. For this purpose, heating wires are also laid in loops in the asphalt.

However, this type of street heating has a poor environmental balance compared to geothermal heating, especially if the electricity is not obtained from renewable energies. In Berlin, for example, there is an electrical pavement defrosting system on Kurfürstendamm with a floor area of ​​around 600 m², with a thermal output of 400  watts per square meter, which leads to a total output of approx. 240 kW. On a snowy day, there is an electricity requirement of 5760 kWh for defrosting, which corresponds to the annual electricity requirement of two families. Based on the electricity mix of the basic supplier Vattenfall, which operates in Berlin, the operation of the defrosting system releases around 3 tons of carbon dioxide per day . The total annual running time was initially estimated at around 250 hours, but initial experience only shows around 126 hours per winter. In contrast to street heating, which constantly ensures a floor temperature above zero degrees, the system is only put into operation when precipitation is added to the cold.

Heating technology for other modes of transport

aviation

Using the techniques of street heating it would be possible in principle, even the runways , as well as the run-up to keep from airports ice. In the 1930s, a runway heating system was installed for the airfield of the Hugo-Junkers-Werke , and in 1972 Zurich Airport received heating for aircraft parking areas. However, such heating systems are seldom installed in modern airports, especially since the size of the area to be heated would lead to high investment costs.

Rail transport

Point heating systems are widely used in rail transport to protect the moving parts of a railway point from icing over, even in frosty conditions. In contrast to road traffic, there are only limited reliable alternatives for points, so that at the beginning of 2011 around 72 percent of the approximately 69,000 points in the DB network were equipped with point heating. In 2008, 90 percent of these heaters were operated electrically, with the heating output of electric point heaters ranging from around five kilowatts (for small track radii) to around 50 kilowatts for high-speed switches. In individual cases, entire track sections, for example on bridges, are heated.

Web links

Commons : Street Heating  - Collection of pictures, videos and audio files

Individual evidence

  1. ↑ a b c Geothermal energy ensures traffic safety. Study. (PDF; approx. 9.1 MB) (No longer available online.) Ministry of Transport, Energy and State Planning of the State of North Rhine-Westphalia, June 16, 2005, archived from the original on March 4, 2016 ; Retrieved August 10, 2013 . Info: The archive link was inserted automatically and has not yet been checked. Please check the original and archive link according to the instructions and then remove this notice. @1@ 2Template: Webachiv / IABot / www.geoversi.nrw.de
  2. ↑ a b First German street heating system against ice and snow. welt.de, March 15, 2012, accessed on July 27, 2013 .
  3. ↑ a b Feasibility study gives the green light for geothermal street heating. Federal Geothermal Association, March 16, 2012, archived from the original on April 26, 2016 ; Retrieved July 27, 2013 . Info: The archive link was inserted automatically and has not yet been checked. Please check the original and archive link according to the instructions and then remove this notice. ; no longer available; available at: archive.org: @1@ 2Template: Webachiv / IABot / www.geothermie.de
  4. ↑ Ursula Spitzbart: Between light and dark. Dryas Verlag 2010, p. 115.
  5. ^ Electricity guzzlers on Kurfürstendamm. Heated sidewalk: beautiful luxury or waste? Tagesspiegel , January 16, 2013, accessed on July 31, 2013 .
  6. ↑ a b qiez.de: Walkway heating at House Cumberland - Investors defend themselves , by Tina Gerstung, February 1, 2013
  7. ^ HR basement: Zurich Airport: Snow-free parking spaces thanks to open space heating. Plumbing and heating technology November 1976.
  8. ↑ Zurich heats 15,000 m² apron - Heated Apron for Zurich, Airport Forum No. 4, Wiesbaden 1974.
  9. ↑ Why there is no runway heating. handelsblatt.com, December 21, 2010, accessed August 4, 2013 .
  10. ↑ number of the month . In: DB Welt , issue 2/2011, p. 10.
  11. ↑ This is how DB wants to stand up to snow and ice . In: DB Welt , December 2010 edition, p. 5.
  12. ↑ Point heating systems at Deutsche Bahn AG . In: Deine Bahn , Issue 1/2010, pp. 51–56, ISSN  0948-7263 .
  13. ↑ Project: upgrading the track bridge BMW - Munich . http://www.triples-systeme.com/referenz/ertuechtigung-gleisbruecke-bmw-muenchen/