Temperature Control in Underground Environments

Controlling temperature and dust is critical in mining and tunneling sites. Underground environments are especially challenging. Nephos industrial installations at the Alptransit site (The world's longest underground rail tunnel) allow an efficient reduction in temperature of  5-7°C on a volume of air of 170 cubic meters/second while dramatically reducing harmful particulate dust.

How it works:


Dust is generally hygroscopic, which means that its mass increases with the water it absorbs. Even a small amount of water is sufficient to cause dust particles to precipitate. The micro particles of water diffused in the air tend to lump the more or less fine dust together, and form clusters of bigger and bigger particles until drops are created. Dust itself triggers and encourages this process.


Nebulised water droplets capture, accumulate and drag the solid particles present in the air along with them to the ground. Their small size makes it possible to leverage the dipolar electric nature of the water molecule, attracting the electrostatically charged dust particles.

The negative ionization of nebulised water further reinforces the action of the electrostatic-hydraulic filter. Further, nebulisation exponentially improves the surface-to-volume ratio of the drops. In fact, a single drop of water with a diameter of 4 mm corresponds to 8 million nebulised droplets with a diameter of 20 microns creating a contact surface area as much as 200 times higher than a single drop. The formation of a blanket of fog thus makes it possible to achieve dramatic reduction of dust, to control and lower gaseous vapours and to cool off the environment. The overall quantity of water used is much less than spraying and creates a damp but not muddy floor to keep the dust from rising.