Incredible Ice Castles Grown by a Minnesota Man Using Geothermal Heating System

Winters in <a href="http://inhabitat.com/minnesota-twins-to-start-the-season-in-a-great-green-ballpark/" target="_blank">Minnesota</a> are cold and the best way to get through the bone-chilling season is to have fun with it, just like Roger Hanson does. For the last four years the ice builder has been growing ice <a href="http://inhabitat.com/incredible-cathedral-built-by-one-man-with-salvaged-materials/" target="_blank">castles</a> in his front yard with the help of his <a href="http://inhabitat.com/uk-engineers-search-for-geothermal-reservoirs-under-newcastle/" target="_blank">geothermal</a> heating system, some fancy sprayers and a computer program he created himself. Each year the crystalline castles at <a href="http://winterwaterwonder.com/" target="_blank">Hanson's Winter Water Wonder</a> are getting bigger and bigger with more intricate rigging systems and more complicated programming.

These amazing sculptures are made possible because of Hanson's geothermal heating system used to heat his home.

As you will recall, a geothermal heat pump works like a reverse refrigerator taking heat from one source and rejecting cold into another.

In Hanson's case, his system takes ground water at 47 degrees to preheat his home and then rejects the water at 37 degrees into the pond near his home.

During the winter, he takes this super cold, but not frozen water and uses it to form his ice castles.

Cold water is constantly dripped through lines (so it doesn't freeze) and sprayed through special nozzles onto the frames Hanson has built.

The sprayed water freezes in place and over a couple months, the ice castle has grown to its ultimate height of 65 feet.

Hanson also created a specialized computer program to control the sprayers, which take input from a weather station on his roof to adjust for temperature and air direction.

Once the water is sprayed, it takes on a life of its own in the ice crystals and shapes it forms.

Hanson's first castle started in 2007 grew to about 16 feet with two levels.

In the 2008-2009 season, it transformed into a crazy monolith with crazy ice points jutting out from it.

The completed 2007-2008 ice castle.

The 2009-2010 version included spires and turrets and finally this year the giant ice castle is a tall, long wall measuring 65 feet at its height and 85 feet long with multiple tiers of ice layers.

This year's project began in November when Hanson set the poles and then he started growing the initial layers the first week of December. Now that it's February, the ice castle will start to melt and eventually disintegrate around the end of April.