I read with interest your article ‘Cooling the Tube’ (Feature, 16 January) concerning the overheating problem on
I noticed the comment ‘taking a systems approach’, but only read about discrete actions being taken.
Although I have little knowledge of the Tube, it occurred to me that by taking the systems approach termites solved the problems of underground overheating many years ago.
I would have thought that by utilising the overheating energy to drive natural ventilation (as the Cornish tin miners used fire and chimneys) using up-draught stacks at high points and down-draught stacks at the low points, would both ventilate, and circulate the air within the system. Trains could be used as pumps/fans.
Smoke/fire protection would have to be taken into consideration along with all other safety aspects.
The problem on the underground system appears to be humidity. the heat is picking up the moisture which once cooled the system, but if natural ventilation is used, the air coming in will reduce the humidity — especially as the system would run 24 hours a day, seven days a week to give night-free cooling.
I think this kind of approach would be much more energy efficient, and would possibly result in a much more pleasant system, giving possibly a sense of wellbeing for all who use it.