Last January, when a blizzard slammed the East Coast with up to three feet of snow, many of us just wanted it to go away. A few months later, sweltering during the hottest summer on record, we wished we had saved some of it.
Hyperbole? Not really. Several countries already are experimenting with storing excessive winter snow and using it later as a cooling agent during the summer, Japan and Sweden among them. They see it as a smart and economical way to save energy, cut air conditioning costs, reduce emissions and make good use of what most people typically regard as an inconvenient nuisance.
Recently, two Canadian scientists examined how snow can best be used for cooling in their country, concluding in a study published in the journal Clean Technologies and Environmental Policy that such a system is more effective in lowering greenhouse gas emissions, with fewer environmental impacts, than conventional air conditioning — and cools just as well.
“Snow is not a waste, but a resource,’’ says Kasun Hewage, associate professor of engineering at the University of British Columbia, Okanagan campus, one of the study authors. “With temperatures rising in many areas, and with them, air conditioning bills, we as societies are increasingly looking at resources and materials differently. Snow has traditionally been seen as a costly form of waste… instead of being seen as a potential source of energy and cost savings.’’
The UBC study, a computer modeling exercise, found that directing a building’s air handling units through a snow dump — a mass of snow collected and cleared from roads in the winter — lowers the need to use traditional air conditioning when the weather is warmer, at least in Canada. But they believe the process is applicable elsewhere.
“It is a proven technology… [but] the economic feasibility of this is climate-dependent,’’ Hewage says. “Many of the questions surrounding efficiency and viability depend on how much snow the area gets and how much air conditioning is required in the summer.’’ In Canada, he adds, “many areas in Ontario, where electricity prices are quite high, seem to be good candidates.’’
The study included simulations for large buildings, taking into account the equipment needed both in conventional systems and snow-dump based systems, which insulate collected winter snow for later use when it is hot.
“The potential of this type of system to be used for large buildings and institutions looks promising,’’ says Rehan Sadiq, professor of engineering at UBC’s Kelowna campus and co-author of the study. “This type of system could eventually help large organizations, such as municipalities, recoup some of the considerable costs associated with snow removal.’’
Air conditioning systems would need some retrofitting for the process to work, according to the researchers. “The type of technology we are talking about is very similar to what is used in geothermal heating and cooling systems, which benefits from cold temperatures beneath the earth surface in the summer,’’ Hewage says, although rather than lines going into the ground, they would lead to the snow deposits. “This technology runs material through the snow pack and essentially shifts cold temperatures from the snow to the building’s ventilation system.’’
But they acknowledge that such a system might be less economical in areas with limited snowfall. “Yes, they [the systems] could work, though unless electricity prices were extremely high, it would be difficult to make the business case,’’ Hewage says.
Other countries have been trying this for several years. On the large Japanese island of Hokkaido, for example, where the winters are very cold and icy, snow harvested during the winter is stored in special warehouses and used to keep food cold, and later, for air conditioning. In Bibai, a city on the island, the snow preserves farm products, keeping refrigeration costs well below that of electricity.
When it is warm, snow warehouses attached to residential condominiums cool the buildings either by circulating air between the warehouse and the rooms, or by circulating cold water from melted snow.
A report from the Hokkaido Bureau of Economy, Trade and Industry notes that residents of snowy and cold regions, who otherwise would consume large amounts of energy, and spend considerable money clearing snow, could access energy sourced by snow as an inexpensive and “highly valued” alternative to oil that “emits no carbon dioxide.”
In Sundsvall, a town in Sweden, such a snow cooling plant system, believed to be the first of its kind in the world, has been successfully keeping the county hospital there cool in the summer since 2000. It not only keeps people in the facility cool, but also helps prevent sensitive equipment from overheating.
Prior to building the Sundsvall snow cooling system, a piece of land just west of the hospital already was a snow deposit site, having been used by the local municipality to dump snow cleared from the streets. This made it a logical — even perfect — place for the new cooling plant. The facility stores the snow in a 23-foot deep bowl-shaped basin made out of waterproof asphalt, which provides insulation. During the winter, snow is put into the bowl. During the spring and summer, the snow is covered with a layer of wood chips to keep it from melting.
The Canadian researchers have not conducted a detailed cost estimate for snow storage systems, nor have they calculated savings, because “cost savings will be highly variable depending on region, due to the variations and duration of heat experienced in summer months, as well as regional electricity prices,’’ Hewage says.
Nevertheless, their study “shows that it is possible to use snow to reduce electricity consumption in structures such as apartment buildings,’’ he adds. “We also now know that using material from snow dumps to cool buildings can also help reduce the greenhouse gasses that air conditioning units emit.’’
Marlene Cimons writes for Nexus Media, a syndicated newswire covering climate, energy, policy, art and culture.
