The energy grid of Raksila sports centre will halve the carbon emissions from buildings
Oulu is involved in the Energy Wise Cities project, which seeks local means of reducing carbon emissions. Raksila Sports Centre has the largest potential for this. “The ice and swimming halls are the two City facilities that consume the most energy,” says the City of Oulu’s energy specialist Johanna Mäkelä. When the third City-owned facility, Oulu Hall, is counted in, the buildings consume as much energy as 10 residential blocks. “The energy-saving measures taken in Raksila have a huge impact on the City’s climate goals.”
The energy vision for Raksila, devised by Sweco, shows how the buildings’ energy flows can be circulated around the area. One of the options is directing the ice hall’s condensation heat into the district heating network. “However, this solution proved more financially challenging than the other options,” says Timo Heikkilä, Sweco’s specialist in sustainable and smart construction.
On the other hand, a heating and cooling grid shared by the three buildings worked like a dream. “The ice hall and the swimming hall are a perfect match, since one needs constant cooling while the other needs heating,” Heikkilä says. With heat pump technology, the condensation heat from the ice hall warms up the swimming hall for most of the year, and even Oulu Hall gets its share of the heating.
Up to 90 per cent savings in delivered energy
The three-building energy grid saves up to 90 per cent of purchased and delivered thermal energy. For the swimming hall, this means annual savings of 120,000 euros, and for the entire area, 200,000 euros. The condensation heat produces almost seven gigawatt-hours of energy, thanks to which only one gigawatt-hour of district heating is needed. “This way, the energy grid reduces the buildings’ carbon footprint by half,” Heikkilä says.
It was crucial for the City’s decision-making that the pay-off period of the energy grid’s implementation is only six years. “All measures suggested in the vision have already been implemented and included in the project plan for the renovation of Raksila swimming hall. We are also planning to use the solution model in other swimming halls in Oulu,” Mäkelä says.
Potential for many cities and municipalities
The Raksila energy vision has gained immense interest in Finnish cities and interest organisations. “The results have positively surprised many municipalities,” Mäkelä says.
Heikkilä sees the City of Oulu as a pioneer, but other cities also show potential in areas where a single operator owns multiple properties. “In many cases, one building needs heating and another needs cooling, so this point of view should be expanded from an individual plot to the block level.”
Usually, area-specific energy analyses do not face challenges with technology or lack of knowledge, but with the ownership of the buildings. “Contract-wise, it’s much more complicated to plan an entity with multiple property owners,” Heikkilä says. “Then again, energy grids provide opportunities for cooperation and synergy benefits, even between multiple operators.”