Building codes require that public buildings have either natural ventilation or mechanical ventilation.  Our school is actually a hybrid system as it satisfies the natural ventilation code requirement to the openable areas of the windows while also incorporating mechanical ventilation.  The idea behind natural ventilation is such that when it seems too stuffy inside, a window can be opened.  However, in the winter when the outside air temperature is cold, this is less likely to happen.

Therefore, we incorporated a mechanical ventilation system that draws air in from the outside.  There is the same problem with the winter conditions, so this mechanical system heats the air before it enters the room.  We, however, took this concept one step further.  Thanks to the design efforts of Chris Vreeland and the folks at Climate Heating and Cooling, we have incorporated Solar Walls into our HVAC system.  These solar walls are specially perforated collector panels installed several inches from a south facing wall, creating an air cavity.  This metal cladding is heated by the solar radiation form the sun, and ventilation fans create negative pressure in the air cavity, drawing in the solar heated air through the perforations.  The air is taken off of the top of the wall since hot air rises and that ensures that all of the solar heat produced is collected.  The heated air is then ducted into the building through a connection to the HVAC intake.  The heated fresh air is then distributed into the building.

This mechanical ventilation system is controlled by a CO2 meter in each room.  When the Co2 levels reach a certain point, the mechanical ventilation system is switched on, providing fresh air to the students and school community.