Infrared Training Center

Tuesday, February 18, 2014

Infrared Everywhere, Even Where It’s Cold

During a recent visit to Waterville Valley, New Hampshire, I had the chance to capture some thermal video of snowmaking operations at their new tubing facility. The year-round resort, located about 90-minutes north of ITC’s Boston-Regional Training Center, is a popular ski and snowboarding destination in New England. It’s been a pretty good year for natural snow here in the northeast, but even then many resorts still rely on artificial snowmaking to help supplement what Mother Nature provides.

The air temperature was only about 10˚F (-12˚C) in this situation. Given the conditions, the water supply ends up looking quite a bit warmer relative to the surrounding environment.  This gives it the appearance of being warm when it’s really not.  That’s because the upper span limit of my imager was set to approximately 25˚F (-4˚C).  Anything near that threshold shows up as yellow or white “hot” on the color scale in the thermal video. 

It’s a great reminder as to why thermographers should check their scale (i.e. span/level) and color palette settings when using an infrared camera, regardless of the application. Just because something may look hot, that isn’t necessarily the case.

Now snowmaking is obviously a process that is thermally dependent on the weather.  It has to be cold, but did you know that ski resorts can still make snow if the air temperature is slightly above freezing? According to a fact sheet provided by the Waterville Valley Resort, all it takes is the right mixture of air and water combined with very low humidity.

In addition to the fan-type unit seen in this video, the resort also uses compressed air snow guns that throw out a specific mixture of pressurized air and water. We all know what happens to the temperature of air, however, when it’s compressed and in this process it can get as hot as 200˚F (93˚C); far too warm for what’s needed.  As such, it first needs to be cooled to about 48˚F (@9˚C) and then loses an additional 10˚F (@5.5˚C) as it’s distributed up the mountain through a network of piping that runs adjacent to the water supply lines.

Of course there is a lot more to the operation including the electrical systems, motors, and pumps, plus the dedicated snowmaking crew which runs it all. Combine that with what needs to happen thermally and it’s pretty amazing to think about what goes in to making something as simple as snow.

- Matt Schwoegler, ITC

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