Indoor climate design with demand-based 4-way chilled beams

Advanced 4-way active chilled beams with integrated variable airflow function provide demand-based ventilation based on room occupancy. They are equipped with water-based cooling coils covering excess heat loads. The target of indoor climate design with these room units is to maintain a good thermal environment for occupants in varying conditions.
Indoor climate conditions in office and meeting rooms with 4-way chilled beams were measured in a full-scale test room. Heat gain levels in different cases varied from 46-92 W/m2,floor and cool ventilation airflow rate requirement from 1.8-4.3 l/s,m2,floor. The cooling capacity requirement from the water side with 16 °C ventilation air was 58%-49% of the total needed cooling demand to main-tain the room temperature at 25 °C. Designs of demand-based 4-way chilled beams were performed with the design tool. Indoor climate designs and measured indoor climate conditions were compared.
The air distribution and generated indoor climate were visualized in different cases. The measured maximum room air velocity levels in the occupied zone were similar to the indoor climate designs performed with the design tool. When the heat gain level increased, velocity levels increased. Convection flows generat-ed by the heat gains in the room significantly influenced the behavior of the sup-ply air jets, particularly in the middle of the room. These interactions could not be predicted by the design tool with semi-empirical turbulent jet models. The re-alistic velocity data for supply air jets is crucial for ensuring good indoor climate conditions in indoor climate designs under different operating conditions.