Monday, October 20, 2008

How a Snowmaker Works

You've seen the snowmakers on the side of the hill at your local ski hill and wondered to yourself, "How do those work?" As far as you can tell it looks like a giant sprinkler, spraying water high above the slopes so it freezes and turns into snow. But could it really be as simple as spraying a light mist of water into the air? The answer is yes...and no.

You see, water is a funny little liquid. A natural water droplet that forms after being pushed through the nozzle of a spray bottle, sprinkler, or pressure washer may not freeze, even if it is cooled well below freezing. Known as "supercooled" water, these droplets just can't seem to form themselves into a frozen crystal because in order for these natural droplets to freeze, they needs something to freeze onto. That's right, without something to attach themselves to, water droplets can remain liquid even if it is well below freezing! That's why some places in the world get freezing rain. This form of precipitation is simply supercooled water, the second it hits the ground though (or a tree, car, house, etc) it freezes, creating an amazing but dangerous layer of ice wherever the storm passes.

So how the heck do you get water to turn into snow then? The most common way is to break down the water into even tinier, unnatural particles using compressed air. By running compressed air through the nozzles along with the air, the water is "atomized", or broken down into tiny droplets. These unnatural droplets actually will freeze in cold air. Plus, expanding air looses heat, so this system also cools these droplets, further helping the freezing process.

However, making each droplet "freezable" using compressed air isn't always the most efficient thing to do. Most snowmakers will use two types of nozzles on each machine. Remember that natural water won't freeze unless it has something to freeze onto? Well, the first type of nozzle runs water and compressed air, making snow crystals. The other type of nozzle sprays only a fine mist of water. However, the nozzles are positioned so that the mist from the water-only nozzles will mix with the snow crystals from the air-water nozzles. The plain water freezes onto the snow crystals multiplying snow output without requiring extra compressed air. When you see large, barrel shaped snowmakers, frequently they will have one ring of air-water nozzles and many rings of water-only nozzles.

Snowmaking technology is now making a movement from the ski hill to the backyard. The same technology applies, but instead of high pressure water pumps, home snowmakers use a pressure washer, like what you use to wash your car with. Usually, these snowmakers use a vertical setup where the air-water nozzle is on the bottom, with as many as four water-only nozzles are positioned above. Small shop air compressors are used to supply the compressed air side of the recipe making home snowmaking incredibly easy and affordable.



Article Source: http://EzineArticles.com/?expert=Gregg_Blanchard

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