Climate change: "Architecture faces paradigm shift"
Due to climate change, buildings in Switzerland will have to be heated less in winter and cooled more in summer in the future. Researchers from the Institute of Building Technology and Energy at the Lucerne University of Applied Sciences and Arts investigated what this means for the construction industry.
A Study of the Lucerne University of Applied Sciences and Arts shows what temperatures we will have to expect in residential buildings in the future due to the temperature increase caused by climate change. Research was also conducted into how heat can be reduced indoors in the most climate-friendly way possible. "Innovative approaches are particularly needed in cities. Here, temperatures will rise even more in summer, mainly due to sealed floors," says Gianrico Settembrini, research group leader at the Institute for Building Technology and Energy at the Lucerne University of Applied Sciences and Arts, which conducted the study on behalf of the Swiss Federal Offices of Energy and Environment.
In collaboration with Meteo Schweiz, the team from the Lucerne University of Applied Sciences and Arts has simulated a future scenario that shows how the room temperatures of four real buildings - two new and two old buildings in Lugano and in Basel - will develop and how this will affect their energy requirements.
For a reference building "new solid construction according to Minergie standard" in German-speaking Switzerland, the calculations show a total of 27 hours of overheating in the average warm year 2004. For the year 2068, on the other hand, around 900 hours of overheating are already predicted. In Ticino, such a building would even experience 1,400 hours of overheating in 2068. A building is considered "overheated" during the summer half-year if the temperature inside exceeds 26.5 degrees.
As a rule, old buildings overheat less, mainly because they have smaller windows. However, they are less insulated against cold and thus reveal their disadvantages in the winter months.
The decisive factor is the cooling
"Architecture is now facing a paradigm shift," Settembrini says. "Protection against cold is still important. But our data shows that the need for heating will be reduced by 20 to 30 percent in the future." Crucial to designing comfortable homes in the future, he says, will be cooling.
In this context, the study authors emphasize the central role of careful building planning: With optimal sun protection and sufficient night cooling, comfortable indoor temperatures can be achieved even without air conditioning, they write. A key function here, they say, is the proportion of windows in buildings. "This doesn't mean we have to go back to living in dark apartments with small windows," Settembrini says. "Large windows on the south façade - at least in the Central Plateau - are still recommended in the future."
In the future, architects will have to design window fronts in such a way that the flat winter sun enters the building, while the high, intense summer sun is screened out. In addition, they would have to include shading systems in the planning right from the start.
The heat transfer to the inside and outside should be adapted to the location of the building in each case, and in addition, strong heating of the rooms could also be cushioned with innovative cooling systems, says Settembrini. One example, he says, is "geocooling." Here, the building's heat distribution system, such as the underfloor heating system, removes heat from the living spaces in the summer months, transfers it to the ground via a heat pump and stores it there. In winter, the system works in reverse: the heat pump uses the thermal energy stored in the ground to heat the building.
