The e-stack natural ventilation system uses technology filed for
patent by the University of Cambridge which is designed to ensure a
minimum rate of air change between a building and the exterior in
Winter to comply with Part F of the building regulations, whilst
minimizing the heating energy required. This is achieved by mixing
the incoming cold fresh air in Winter with hot interior air prior
to it reaching the occupants. The system ensures that the air
quality remains very high but also that the building is totally
comfortable to avoid the risk of cold draughts which are often
associated with natural ventilation systems.
In warmer weather the system typically operates with higher
ventilation flow rates in order to minimize the risk of
overheating, although it can be used in conjunction with thermally
massive building types to exploit the benefits of passive
night-cooling in which case lower ventilation rates are again
used.
Data collected at Harston School in Cambridgeshire shows how the
e-stack system provides a much better quality environment in
winter. Over a two week period in winter 2008, we turned the
e-stack system off on Tuesdays and Thursdays and observed
considerably higher CO2 levels as a result of inadequate
ventilation. Under normal e-stack operation children aged 5-6 are
in the classroom wearing just their school jumpers close to the
vent.
