We have just completed a 100kW community hydro scheme in which the building is cooled by a passive ventilation system (near floor level vents for incoming cool air and heated air leaving through high level vents).
Today the generator set got a little to warm (running flat out at 100kW). This suggests as we thought during the design phase that we need a little more ventilation, however we don’t want the building getting too cold in the winter so would like to put thermostatic valves on the vents.
Has anyone know a supplier for basic mechanical thermostatic dampers that would fit the 100mm ducting we are using.

Ed, very interesting idea.