London seeks ways to cool the Tube

link : http://uk.news.yahoo.com/040831/80/f1mhb.html

LONDON (Reuters) - Britain may not be renowned for its tropical temperatures but in the summer there is one guaranteed hotspot: the London underground.


Hundreds of thousands of commuters sweat their way to work daily on the world's oldest subterranean rail network in sauna-like conditions that some politicians say are unsuitable for transporting livestock.


But relief may be imminent for passengers who wonder why summer temperatures on "The Tube", as the network is known, should top those of the metro systems of Mexico City or Milan.


Plans are underway to install a cooling system that would tap the millions of gallons of cold ground water pumped daily out of London's deep tunnels in order to cool air in the labyrinthine network. Trials could begin before next summer.


Not a moment too soon for harassed Londoners who already endure frequent delays and overcrowding on the ageing Tube.


"One of the things most repugnant about the Tube, apart from the crowds, is the temperature," said Nick Giesler, a 40-year-old environmental consultant, after his morning rush hour commute.


"It's particularly bad now but it's never very pleasant."


Conditions on the Tube hit the headlines last August, at the height of the hottest summer for decades, when temperatures underground topped 40 degrees Celsius (104 Fahrenheit).


London Mayor Ken Livingstone offered a 100,000 pound reward for the most workable solution to cool the Tube -- used by 150,000 people an hour or enough to fill two football stadiums.


The "Beat the Heat" competition drew 3,400 entries including suggestions to put up posters of snowmen or hand out ice lollies. Most were dismissed as ineffective or unfeasible.


The Tube revolutionised transport 140 years ago and served as a model for other systems around the globe but many Londoners now bemoan the system as unworthy of the capital.


"Compared to what they have abroad, it's a nightmare," said Ruth Bifield, 54, a project manager, waiting on a platform. "Even Russia is better and they have appalling infrastructure."


Modern metro systems like those of Hong Kong or Singapore were designed with enough room in tunnels for air conditioning units but little thought was given to air conditioning back in the 1860s and London's tunnels have space only for the trains.


Air pressure ventilation systems are slowly being fitted to trains but engineers have struggled for decades to find ways to cool the entire network. Traditional air conditioning poses problems since it produces heat, which must have an exit route.


ALL HOT AIR?


Now London Underground, which runs the Tube, hopes an innovative system using excess ground water will do the trick.


"The cooling resource is there, it's in the right place and there is masses of it," said Graeme Maidment, a senior lecturer at South Bank University who helped devise the scheme.


The idea is to blow hot air over pipes carrying cold ground water. The water would rise in temperature as it absorbs heat from the air. The cooler air would then be blown back onto the platforms and the warmer water pumped out.


Maidment says the system could cool air temperatures by 7 degrees Celsius (about 13 degrees Fahrenheit). The plan is to test a prototype at Victoria, London's busiest Tube station, next year.


Even if it works, it would take years to install the system throughout the network.


In the meantime, passengers will have to settle for more traditional cooling methods such as newspaper fans or water. As they enter the Tube, a recorded message advises commuters to carry bottled water and not to travel if they feel unwell.


But water is little defence against the ultimate nightmare: getting stuck on a train more than 60 feet (20 metres) underground in the height of summer.


"Most people make relatively short journeys on the Tube but when trains get stuck in tunnels due to train failure or signal failure the temperature rises because there is no ventilation. This can become an issue," said a London Underground spokesman.


In the summer, the Tube has emergency procedures to get people out of trains as soon as possible -- including walking them through dark tunnels to platforms, the spokesman said.


Many Londoners would welcome a cooler commute but remain sceptical.


"You will know when it happens: it's when the fares go up," said Brendan Giblin, 32, a building surveyor who sweats his way to work every morning in a heavy suit.


Others ask if it is worth investing in cooling systems.


"The Tube is very warm in the summer, but then the summer only lasts two weeks," joked one commuter.