A trial for an innovative scheme to cool Victoria Station on London's Underground was due to begin as GE went to press.
The system aims to use what is thought to be a subterranean river, which once fed London via leather pipes, to cool the station as temperatures in the capital reached the mid30s last month.
A Transport for London (TfL) spokesman said the temperature on trains, which can be a few degrees above that on the surface, could be signi cantly higher if they stopped in tunnels.
The project will involve water at about 12°C from the underground source being pumped through pipes into heat exchangers in the station.
These will act like reverse radiators as warm air is blown over them, after which the warmed water will be ushed away.
'This is something we have been looking at with London South Bank University, to use a ready source of cold groundwater, from what we think is the River Tyburn, through a series of pipes, ' said the spokesman.
'Metronet [the company responsible for maintenance of this and some other sections of the Underground] has started to install the equipment and the trial should begin in days rather than weeks.' A T-bar will take ow from an existing pumping system through a bypass to the fan-cooled heat exchanger.
Professor of mechanical engineering at London South Bank University, Graeme Maidment, said: 'We are cooling the concourse area of the Victoria Line with water from about 30m below ground level. It could make a difference of about 3°C to 5°C. This difference, added to air movement from the trains having a piston effect, as well as from gravity, would make a signicant difference to thermal comfort. It will be interesting to see how the air displaces as it is very hard to predict.' If the scheme proves successful, TfL may use it at other stations where there is a water source, or look at piping water from Victoria to other stations.
But Maidment said although this is a small prototype built with a view to using the technology at other stations, one problem of getting water around the network is the Victorian tunnels. These were only designed to accommodate trains and there is little room to get pipes through.
However, he said other stations such as South Kensington had their own water sources.
The trial is likely to continue for months. 'Being a new technology and an innovative piece of engineering we do not know how long it will take to have an effect. We may nd it works instantly or takes a period of time, ' said the TfL spokesman.
TfL is also looking at improving ventilation and increased use of fans to cool stations.