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YIT Office building, Turku Finland AdVent Case 9

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The building has an air-conditioning system with mechanical supply and exhaust ventilation and chilled beams. The building is connected to Turku area district heating and district cooling distribution systems. The temperature of water in the district heating main varies between 65°C and 115°C for the supply and between 40°C and 60°C for the return water, depending on the heat demand. In the district cooling network the delivery temperature is +7°C and the return temperature +17°C. District cooling water is produced with free cooling (outdoor air) and compressor technology. All the heating and cooling systems in the building are connected indirectly to the district networks through heat exchangers. Heat extracted from the district heating network is used in the building for domestic hot water and space heating through central air handling units and hot water radiators. The district cooling water system serves both the central air handling units and chilled beam units installed in the open-plan and cellular office spaces. The chilled beam units have integrated, control equipment, supply air cooling heat exchangers, fluorescent lighting and a communication link to building management system (BMS). Outside normal office hours, the BMS sets lights in the units by default to ¼ power and lighting demand is controlled by IR motion-sensors. Ventilation and air conditioning strategy: The building is divided into five ventilation zones.
YIT Office Building is a typical modern five-storey office building and was completed in October
2005. The ground floor (900 m²) serves as a workshop and storage facility and the remaining four
floors (6 000 m²) have both open-plan and cellular office spaces. There is a large glass roofed
atrium in the centre of the building extending  from the first floor to the roof. In the lower part of
the atrium (at the second floor) there is a cafeteria and a small kitchen (the second floor partly covers the atrium). A total net floor area of the building is 6 906 m² with a total volume of 34 000 m³.

Acronym of the case

AdVent Case 9

Author(s) information


Jarek Kurnistksi



Jari Palonen


Lessons learnt

In a cold climate heating of the ventilation air is the most significant heat loss especially in the non-residential buildings. To achieve adequate energy performance of the building, the use of controlled ventilation rates and heat recovery is essential in a cold climate. For that reason natural ventilation systems with high ventilation rates and no heat recovery cannot be used in a cold climate. Energy performance of described ventilation system is achieved through effective heat recovery in the air handling unit. Another benefit is low specific fan power (electricity use of the ventilation system) due to relatively low ventilation rates. As ventilation rates are based only on the ventilation need caused by human occupancy, they are significantly lower compared to all-air systems where ventilation rates are based on cooling or heating need. To achieve low specific fan power, low pressure design of ductwork and demand controlled ventilation control in meeting rooms are used.

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