In summer, temperatures at the bottom of London Underground can be very uncomfortable because of deep and bad ventilated tube tunnels: temperatures as high as 47 ° C (116 ° F) are reported in the 2006 European heat wave. Poster can be observed on the Underground network telling that passengers carry a bottle of water to help keep it cool.
Video London Underground cooling
Sumber panas
The heat in the tunnel is mostly generated by trains, with small quantities coming from station equipment and passengers. Approximately 79% absorbed by the tunnel wall, 10% removed with ventilation and the remaining 11% are in the tunnel.
Subterranean temperatures slowly increase when the clay around the tunnel has warmed up; in the early days of the Underground it was advertised as a place to stay calm on hot days. However, over time, the temperature gradually increases as the heat sink formed by the clay has been filled. When the tunnel is built, the clay temperature is about 14  ° C; this has now increased to 19-26 º C and the air temperature in the tunnel now reaches as high as 30 ºC.
Maps London Underground cooling
Cooling method
Tunnels
Heat is extracted from the tunnel using ventilation holes, with air forced out of the vents by a piston effect (trains pushing air forward as it passes through the tunnel) or fan.
Station
The heat pump was piloted in 1938 and has been proposed again recently to address this problem. After successful demonstrations in 2001, funds were awarded to the School of Engineering at London's London South Bank University to develop prototypes; work began in April 2002. A prize of £ 100,000 was offered by the Mayor of London during the summer of 2003 for a solution to the problem, but the competition ended in 2005 without a winner.
A one year groundwater cooling system test started in June 2006 at Victoria Station. If successful, the trials will be extended to 30 other inner-level stations. For this test Metronet installed the University of London South Bank system consisting of three fan coil units using water that had seeped into the tunnel and pumped from the tunnel to absorb heat after it was disposed of in the sewer system. This scheme is one of the winners of the Carbon Trust 2007 Innovation Award.
Tube Train
Newspapers are often thrown into the air vents that are behind the seat, which raises the problem.
Conventional air conditioning has been ruled out in deep lines because of the lack of space for the equipment on the rail and the heat dissipation problem this waste will produce. Different systems have been proposed to cool the subway, including the use of large ice blocks inside the train. The blocks will be stored in cooling units, preventing them from melting completely.
Subway
In 2010, new S-stock trains were shipped to replace the A, C and D trains on the Surface Lines (Metropolitan, Circle, Hammersmith & City, and District). It has a standard AC, because the subsurface tunnel is large enough to replace the exhausted hot air.
More efficient braking
The conventional brakes on the train rely on friction to slow the train down, turning kinetic energy into heat. More modern trains feature a regenerative braking system that can feed energy from braking back to the power supply, minimizing the heat generated. It has the added advantage of reducing the amount of brake dust produced by the train.
References
External links
- Subcool Cooling Websites
- Sustainable Refrigeration Scheme For London CIBSE Underground Railway Network
- Notes from Tube Cooling Lecture 11 March 2008 Kevin Payne Director of Transport for London's "Tube Refrigeration" Program
Source of the article : Wikipedia
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