I&#x27;m not aware of any use of liquid nitrogen to keep general infrastructure cool but it sounds like you&#x27;re referring to the gas tanks that keep wiring under a positive pressure to keep moisture out.<p><a href="http:&#x2F;&#x2F;gothamist.com&#x2F;2008&#x2F;01&#x2F;31&#x2F;nitrogen_tanks.php" rel="nofollow">http:&#x2F;&#x2F;gothamist.com&#x2F;2008&#x2F;01&#x2F;31&#x2F;nitrogen_tanks.php</a>