R-Series Stack Based Ventilation
The R-Series e-stack ventilation units are designed for rooms
which have access to the exterior via the roof and usually with
occupancy levels in the range 10 to ~30 persons. It is ideally
suited to classrooms on the top floor or one floor below the top
floor of a multi-storey building. The R-Series unit is rectangular
in plan, so hence the name.
In winter the system uses a mixing ventilation strategy. Fresh
air is brought in through one half of the divided shaft immediately
above the R-Series unit, where it is then mixed with hot interior
air before being released into the room. Hot polluted air is
exhausted from the room through the other half of the divided
shaft. By using this e-stack strategy, the heat gains which arise
in the room are used for heating the incoming air during
the occupied time rather than a radiator which is required
in conventional upflow displacement ventilation mode to
preheat incoming air at low-level. The heat gains within heavily
occupied spaces (e.g. school classrooms) are often sufficiently
high that additional heating is not needed until the external
temperature falls to somewhere in the range 5-10oC,
depending on the U-value for the room.
Once the external temperature has increased such that air can be
brought in at low level directly onto occupants without
pre-heating, the ventilation strategy for the system changes to
upflow displacement ventilation. Windows or low level vents are
opened, as well as the R-Series unit and any additional high level
windows or dampers so as to maximize air flow and to minimize build
up of heat in the space.