Swedish hospital uses stored winter snow to cool building in summer
A hospital in Sundsvall, central Sweden, used an unusual cooling system that stored winter snow for use during summer. The snow was kept in a large, insulated storage area and its meltwater was circulated through the hospital to provide cooling. Researchers found that insulation was essential, as unprotected snow would melt by mid-June. The study showed that stored snow could meet the hospital's…
In central Sweden, the Sundsvall Regional Hospital has devised an innovative method to meet its summer cooling requirements by utilizing stored winter snow. The hospital, spanning 190,000 square metres, experiences an annual cooling demand of approximately 1,000 MWh, with a maximum cooling power requirement of 1,500 kW. To achieve this, the facility built a snow storage system in 1999, covering an area of 140 metres by 60 metres and having a capacity of 60,000 cubic metres, equivalent to around 40,000 tonnes of snow.
The snow storage area was designed with a shallow pit and a watertight asphalt base, and was covered with a layer of wood chips to provide thermal insulation. This insulation reduced natural snow melting to around 20% to 30% of the total volume. The researchers used simulations focusing on a smaller 30,000-cubic-metre snow storage facility to determine how much insulation was required to maintain snow availability throughout the summer.
When snow and ice melt, they absorb heat, which can be utilized for cooling purposes. The hospital system circulated the meltwater through a cooling system instead of using the snow directly. Water from the snow storage was pumped into the hospital to help cool it, and then the warmer water was returned to the snow storage area, creating a cycle where the stored snow supplied cooling while gradually melting.
Without insulation, the stored snow would have melted before the end of the hospital's cooling season. The researchers found that an uninsulated 30,000-cubic-metre snow pile would have melted by June 17. However, they discovered that with a 0.20-metre layer of sawdust insulation, about 19,040 cubic metres of snow remained through the summer, and with 0.10-metre of sawdust, only about 12,169 cubic metres remained.
The thicker layer of insulation proved more effective at reducing heat transfer from the surrounding environment.
The study concluded that thermal insulation made the stored snow capable of covering the hospital's cooling demand from May to August. The method of using stored snow for cooling is not entirely new; ancient Greeks collected ice from lakes and rivers, insulating it with materials like sawdust, while various Japanese methods, such as Himuros and Yukimuros, also employed similar techniques to preserve ice and snow alongside food.
Modern cooling systems have largely replaced these traditional methods, but this Swedish hospital finds a sustainable way to incorporate them into its contemporary infrastructure.
Written by urgent.news from Times of India's reporting — not their text. Machine-written — may contain errors; check the original before relying on it.
