Montreal City Hall, as a heritage building, presented numerous constraints related to the preservation of the original architecture, historic light fixtures, and marble cladding. The installation of 320 digital controllers on each floor was particularly complex: due to the very high heritage ceilings and the lack of access hatches, the controllers were installed at the base of the fan coil units under the windows, with electrical wiring running through the floors.

The building is supplied by hot water and chilled water networks serving nearly 190 fan coil units spread over seven floors. In this context, our challenge was to optimize the HVAC control sequences in order to obtain precise water temperatures for heating and air conditioning. This was essential to maintain energy performance and ensure uniform thermal comfort, regardless of seasonal conditions and load variations specific to a building of this size.

In addition, the multiple energy-efficient devices dedicated to hot and chilled water production required the development of advanced sequences adapted to each type of device, thus enabling optimal modulation between the different systems and the actual needs of the building.