Skanska Commercial Development Europe has completed the installation of 53 boreholes, each approximately 250 metres deep, beneath the foundation slab of its Nowy Rynek C office building in Poznań. The network will serve ground-source heat pumps as part of a system designed to allow the building to operate independently of the district heating network.
Nowy Rynek is a mixed-use development in the centre of Poznań comprising office buildings and publicly accessible urban space. The ground-source heat pump system will be combined with air-source heat pumps on the roof and a rooftop photovoltaic installation with a capacity of more than 350 kWp, together covering the building's full heating and cooling demand across all seasons.
The borehole network was sized using an EED (Earth Energy Designer) simulation informed by earlier Thermal Response Tests, which assessed ground conditions and the building's projected energy-demand profile. The process allowed Skanska to optimise the number, depth and spacing of the boreholes and reduce the risk of excessive ground temperature changes over time. Heat pumps draw on the relatively stable ground temperature of around 8 to 12 degrees Celsius, operating on a balanced seasonal cycle.
"In Poland, investors rarely opt for ground-source heat pumps in buildings on the scale of Nowy Rynek C. This is often due to concerns about the complexity of the engineering process, the significant cost of drilling and a lack of early-stage planning. We should be looking for new ways to design buildings and plan how they operate, including making bolder use of innovative technologies that enable low-emission heating and cooling," said Przemysław Kubaś, Project Manager at Skanska Central Europe.
Being independent of the district heating network gives the owner the option of powering the building exclusively with energy from renewable sources, backed by Guarantees of Origin. According to the building's energy performance certificate dated 22 April 2026, the projected EP primary energy indicator for Nowy Rynek C is 44.32 kWh per sqm per year, approximately 62% below the maximum value for the reference building under WT2021 regulations.
"From the outset, we designed Nowy Rynek C as a building for the future: one that can adapt to changing market conditions and regulatory requirements. Replacing the district heating network with an innovative combination of ground-source and air-source heat pumps and a photovoltaic installation will allow the building to operate independently of external heat supplies, improve its energy efficiency and reduce operating costs over the long term," said Konrad Ziejewski, Project Director at Skanska Commercial Development Europe.
