What is the difference between natural and artificial snow melt?

Natural snow melt is very attractive if you are a hydrologist. I’m talking about the natural process of natural snow melt in the spring, causing the streams to rush, filling our reservoirs. Man-made snow melt is something else. It features an acronym: SIMS. Snow and Ice Melting Systems are used to keep driveways clear. SIMS are also used for walkways, eliminating dangerous ice in pedestrian ways in cold weather climates. 

Sounds great! What’s the problem with snow and ice melt systems?

Snow and ice melt is costly. It is energy-intensive, and in almost all cases, it is laden with embedded carbon. It takes a lot of thermal energy to melt snow and ice. A snow melt system installer noted that, “Even in our largest residential projects, the snowmelt boiler or boilers dwarf those that heat the home.” 

How much energy do snow and ice melt systems use?

Every square foot of snow melt uses ~ 5-10 times as much energy as every square foot of interior space. Snow melt requires 100 – 250 BTUs/square foot/hour versus an efficient building’s interior space in the 15 – 20 range. If a snow melt system uses electricity, imagine a 75-watt incandescent burning brightly for every square foot of the snow melt system.

What kinds of systems are there? 

There are a number of types of systems and operations. Some systems use electric resistance heating. Larger systems use boilers and hydronic heating. Tubing is placed with 8 – 12-inch spacing in poured, six-inch concrete. Then a mixture of hot water and glycol runs through the closed-loop. Controls limit the number of hours of operation to keep operating costs in check.

What heat sources can be considered for SIMS? 

The heat source can be natural gas, electricity, wood/biomass, waste heat recovery, or solar. Each of these has its challenges, costs, and benefits. There’s no sunshine during snowstorms. Heat pumps bear high upfront costs. Combusting natural gas has severe climatic consequences.

What are the alternatives to snow and ice melt systems?

The alternatives to SIMS are not good. Shoveling is the most basic solution for snow removal, augmented with electric snowblowers. 

What about the use of rock salt to melt the snow and ice?

According to “Mr. Pavement,” salt is bad for your lawn, garden, concrete, pavers, pets, and cars… and gets washed into our lakes, streams, and groundwater supplies. In some areas its use is banned.

Are there natural alternatives to salt for melting snow and ice?

This is a fun list… though several viable candidates might well be hard to scale. For instance, coffee grounds; snow melts quickly due to the acidity of the grounds. Sugar beet juice is reportedly “very kind to the environment,” lowering the melting point of ice and snow. Vinegar, baking soda, wood ash, alfalfa meal liquid cheese brine, and pickle brine are also reportedly viable alternatives. Sand and crushed walnut shells can be spread for traction.

Can ground source heat pumps / geoexchange be used as the heat source for SIMS?

Yes, geoexchange – tapping the earth’s tempered temperatures – is a viable heat source. But the primary and secondary purposes for most GSHP systems is providing heating and cooling as well as domestic hot water. A building’s geoexhange field would have to be massively oversized to provide the thermal requirement for the relatively few hours of snow and ice melt.

How can snow and ice melt be most efficiently used?

1. Limit the amount of area to be served by the SIMS
2. Install high efficiency equipment, heat pumps or boilers
3. Specify and commission sophisticated, predictive controls for the SIMS
4. During and after snow events, shovel the snow to expedite the snow melt
5. Consider purchasing offsets to maintain a net zero carbon position