Experimental Study of a Snow Melting System: State-of-Practice Deicing Technology

This paper presents the experimental study of a snow melting system embedded in concrete sidewalks/slabs at Northern Arizona University (NAU) as a practice of deicing technology. NAU is located in Flagstaff, Arizona. In the winter months with high attitude (7000 feet/2,250 meters), temperatures in Flagstaff are extremely cold and the amount of snowfall (approximately 108 inches/2.74 meters per year) has been significant. As of 2012 NAU has planned to install snow melting systems in sidewalks with the goal to provide visitors, students, faculty, and staff with a stably safe environment for transportation in the snow. Hydronic heating system has been selected to generate heat energy using glycol-water as the heat source. Pipes are embedded 4 " (11.5 cm) below the pavement surface with glycol-water being circulated within the pavement. To help with mechanical system design, numerical modeling along with yearly heat output values in Flagstaff were calculated. In January 28, 2013, a snow storm was blasting across the city. The snow melting systems were turned on at midnight to heat the concrete slabs. Based on an observation in the early morning of the following day at 7am, no snow accumulation was found on all heated sidewalks at the three project locations. The observation has validated our heat output computation and numerical analysis, and has proved they were appropriate. The hydronic system embedded in the pavement was working very well to generate heat energy to keep the snow away from the sidewalk surfaces. To date, the snow melting systems installed at NAU have successfully demonstrated their abilities to heat the pavements and keep the snow from the surface.