| 摘要 |
<p>An underground space (1) is cooled by introducing a liquefied cryogenic gas (9) comprising a human life sustaining proportion of oxygen (for example, liquid air) into the underground space and allowing the liquefied cryogenic gas to evaporate therein. The underground space may be a tunnel (2) or station in an underground railway station. The liquefied cryogenic gas (9) may be introduced into a tunnel between a station and a train (4) moving toward the station, and the train pushes the evaporated gas into the station.</p> |
