Seen at the hybrid ventilation conference are, left to right, Dr. Willen
de Gids (TNO Building and Constriction Research, Netherlands), Professor
Gérard Gurracino (Director of the Laboratoire des Sciences de lHabitat,
École national des travaux publics de l Etat, France), Professor
Per Heiselberg (Aalborg University, Denmark, operating agent of the Annex
35 project), Professor Fariborz Haghighat (organizer of the conference
and Canadian representative on this international research project), Dr.
Peter Wouters (head, Air Infiltration and Ventilation Center, Belgium
Building Research Institute), and Dr. Morad Atif (Canadian IEA ECBCS executive
committee member, Institute for Research in Construction, National Research
Council of Canada).
Photo Andrew Dobrowolskyj
by Sylvain Comeau
Speakers at scientific conferences normally discuss the same topic, but
they are not always on the same page. Last week, Concordia invited speakers
involved in an international hybrid ventilation project to compare notes
with their collaborators.
Experts from 15 countries came to talk about their part in the research.
Fariborz Haghighat, a professor in Concordias Department of Building,
Civil and Environmental Engineering, organized the conference, and is
the Canadian representative on the project. In an interview following
the two-day event, Haghighat and two of the speakers from overseas explained
the merits of hybrid ventilation.
The project was launched four years ago, with the purpose of improving
energy efficiency in buildings, Haghighat said. This is an
increasingly important issue because of global warming and the creation
of greenhouse gases like carbon dioxide. Buildings account for nearly
30 per cent of our total energy consumption, so minimizing this consumption
in any way has a direct impact on the environment. Hybrid ventilation
does this by minimizing the reliance on mechanical ventilation systems.
Haghighats part in the research is to develop computer simulations
to model the systems performance.
It is a new concept in ventilation, which combines mechanical and
natural ventilation [wind], said Per Heiselberg, a professor in
the Hybrid Ventilation Centre in Aalborg University, Denmark. The
idea is that there are two possibilities, the natural driving forces of
wind, or mechanical ventilation and cooling. Hybrid ventilation chooses
the optimal mode that results in the best energy efficiency, while ensuring
good indoor climate and air quality.
Better indoor air should mean fewer cases of sick building syndrome, which
is a growing concern for occupants and building owners. This ventilation
system addresses sick building syndrome by removing contaminants from
the indoor environment, and maintaining a flow of fresh air.
In one of the products case studies, a school was renovated with
hybrid ventilation, and the number of asthma cases at the school dropped
W.F. de Gids, a researcher at TNO Building and Construction Research in
the Netherlands, explained that the key to the system is in the intelligent
One of the keys to optimization is determining the correct amount
of time you should rely on natural versus mechanical ventilation, and
to switch effectively between the two, you need a very intelligent control
algorithm. There are natural and mechanical systems already in place in
most buildings; what is lacking is the computer brain to balance the two.
The project, called Annex 35, includes a number of case studies, buildings
around the world which are designed or renovated to showcase the ventilation
These are first-generation buildings with hybrid ventilation,
said Heiselberg, The buildings have achieved a reduction in cooling
energy by 25 to 50 per cent and the fan energy by 10 to 20 per cent. They
have proven the potential of this system, that it is possible both to
build for greater energy efficiency and a better indoor environment.
While the case studies were developed overseas, Haghighat said that last
weeks conference brings that knowledge to our shores.
These researchers are working together to develop a methodology
for hybrid ventilation, and this conference was intended to transfer this
information to Canadian architects and engineers.
The conference was sponsored by Natural Resources Canada, the National
Research Council of Canada, Concordia, University and the Air Infiltration
Ventilation Centre (AIVC).
The international project is sponsored by the International Energy Agency.
Haghighats part of the research is supported by Natural Resources