by Maria Vincelli
Dorel Feldman officially retired
from Concordias Department of Building, Civil and Environmental
Engineering in 1996, but hes still working on several projects,
among them the search for a building material that can increase the energy
efficiency of your home.
Dr. Feldman, now a professor emeritus, is involved in at least three research
projects, supervises several graduate students, and offers the occasional
reading course to students needing to brush up on their knowledge of polymers,
a topic on which hes published books in Romanian and English.
Chief among his accomplishments is finding and developing an organic phase-change
material (PCM) that can be applied to ordinary wallboard to make it 20
to 25 per cent more energy efficient. He has been working on the project
since he was hired by the then Centre for Building Studies in 1978. More
than 20 years later, Feldman and his research associate, Dorina Banu,
are looking for commercial partners.
It works like this. The PCM absorbs heat as it melts at 23° C. The
heat is stored in the wall until the temperature dips below a comfortable
room temperature. Then the PCM solidifies, releasing the same amount of
heat that it had previously absorbed.
Though the researchers initially found many organic materials that absorbed
and released energy during melting and crystallization, the first
problem was finding materials that melt and solidify at the temperature
we need to have in our living rooms, Feldman said.
The next step was to make sure that the mixture would keep its thermal
properties over years of melting and crystallizing. After testing it for
over 10,000 cycles, the researchers were able to confirm this. Though
Feldmans team has also worked with tiles and concrete blocks, the
wallboard was easiest to prepare and work with in the laboratory setting,
so the initial tests have been with that material. Once they successfully
tried several methods of applying the PCM to the gypsum, they were ready
to present their product to building materials companies.
Its heavier than ordinary gyproc, but Feldmans treated wall
board has no odour, is easy to paint and plaster, and, after months of
testing in a specially built room, does not appear to release any toxic
Why isnt it on the market yet? First, more work needs to be done
to make the treated wallboard less flammable, and the team has been working
on a solution that would make its flammability equivalent to or less than
that of treated plywood, an industry standard.
Second, according to Feldman, who keeps a folder full of requests for
information about the project from researchers around the world, the commercial
interests have backed down.
Initially, Domtar participated in measuring the energy savings, but when
the pulp and forest products company sold its gypsum division in 1996,
it pulled out. Westroc, another producer of wallboard, also co-operated
for some time, but is reluctant to produce it commercially because the
technology for applying the PCM involves drying the board in an oven for
one or two minutes at 200° C.
Theyre afraid of an explosion or fire, said Feldman,
who does not agree that it is a big concern. We dried some ourselves
in an oven and found that the surface of the board was only 100° C.
It doesnt have the time to take the temperature of the air.
Now Feldman, who has received funding for the project from the federal
and provincial governments and NSERC, is hoping that the companies that
produce the chemicals in the PCM will fund the completion of the project.
If they do, he says that the provincial government will probably match
Feldman, who taught polymer technology at a polytechnic institution for
more than two decades before emigrating to Canada, also talks energetically
about his other projects.
In addition to developing energy-efficient wall boards, hes involved
in a $1-million project to examine how air quality in buildings is affected
by building materials and is developing synthetic materials for reinforcing