tdmg vol 3-iss-1_rev1_final
TRANSCRIPT
We have entered into
agreement with Moncion
Technical Services (MTS),
an engineering services
sales company, to increase
our marketing reach and
visibility. We are looking
forward to working with MTS
in the near term.
We are also proud to
announce that we have
been re-certif ied as
compliant with Canada’s
Controlled Goods Program
until July 2014.
Due to the nature of our
analyses, we decided to
acquire an additional CFD
software Fluent. This tool
will allow us to perform
increasingly complex
Thank you for taking the time
to read our newsletter.
We are beginning 2012 in
our new offices located at:
100 Alexis Nihon, Suite 120
St-Laurent, QC, H4M 2N6
We are in the same building
as before but in a new suite.
The new office will give us a
little bit more rented space. If
you are in the area, please
feel free to make a stop and
visit us.
analyses, including large
scale indoor pool and
water park analyses. We
should also be performing
ventilation analysis of a
transportation depot with a
r e q u i r e m e n t f o r
contaminant transport.
In this issue of the
newsletter we will cover the
following items:
- Ventilator CFD analysis
for high heat load buildings
(ex. aluminum smelter),
- Fans and fan curves
- BDC Economic letter
I hope you enjoy these
topics. Please feel free to
suggest anything else that
may be of interest to you.
TDMG News by Bruno Zoccali, President TDMG Inc
Gravity Ventilator CFD Analysis for High Heat Load Buildings
Air-Therm Inc, a major
manufacturer of gravity air
ventilators for industrial
applications have mandated
TDMG to perform CFD
analysis on some of their
products. The analyses have
been used to demonstrate
product performance under
specific operating conditions.
The CFD model includes the
building, pots, inlets, and
roof-mounted ventilators.
The analysis is a natural
convection analysis whereby
the heat generated at the
pots creates the buoyancy
forces which drive the hot air
out of the building.
It is possible to evaluate the
flow regime inside the
building, as well as the
temperature and pressure
distributions.
The CFD results have been
validated against ASHRAE
calculation methodology.
One advantage of the CFD
analysis is that it can provide
detailed information about
the flow, temperatures, and
neutral plane height which
can be difficult to determine
if the building has irregular
geometry.
In the case shown, it was
de te rm ined tha t the
ventilators would provide
adequate flow out of the
building and maintain room
temperatures at acceptable
levels — both from an
operator and structural point
of view.
This was a perfect example
of CFD being used in new
a p p l i c a t i o n s .
For additional information
please contact us or
Air-Therm directly.
TDMG’s News by
Bruno Zoccali,
President TDMG Inc
Please ask us your
questions and give us
some newsletter
ideas
Let us know what you
think about this
newsletter
TDMG Newsletter March 7th, 2012
Volume 3, Issue 1
Inside this issue:
TDMG News 1
Gravity Ventilator
CFD Analysis for
High Heat Load
Buildings.
1
Fans and Fan
Curves
2
BDC Economic
Letter
3
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Air-Therm VG Ventilator
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Fans are the primary air movers in many air-cooled electronic equipment that we design. It is
important to understand how the fan works and what the fan curve means when designing
such equipment. The typical fan curve looks as follows. It is plotted as flow (ex. CFM) on the
X-axis and pressure (ex. inches H2O) on the Y-axis.
Point A (on Y-axis) represents the point at which the fan delivers no flow. The fan is working
against such a high pressure that it is incapable of delivering any actual airflow to the system.
Point B (on X-axis) represents the maximum airflow that the fan can deliver, however, it can
only deliver this airflow against zero pressure (or in open conditions).
The area shown in green is typically the recommended operating range for the fan. The fan is
working at relatively high airflow and relatively low pressure conditions. This makes allowance
for off-design situations. For example, a clogged filter would increase the pressure of the
system, but in this operating region the fan may still be capable of delivering a reasonable
amount of flow.
The area in red is an unstable operating regime for the fan and should be avoided. Although
fan curves vary in shape, this specific curve is flat in this region meaning that a very small
increase in pressure could significantly reduce the fan air delivery and vice versa. The fan
could swing from 40—70 CFM and operate in an unstable mode of operation.
The region to the left of the red area in not a recommended operating region as the fan is
delivering a relatively small amount of flow against a relatively high pressure. Under these
conditions it would be best to look for an alternate fan.
The actual operating point of the fan is determined by the intersection of the fan curve and the
system pressure impedance curve (shown in red in the above figure). The impedance curve
can be obtained by CFD simulation or testing, The system impedance curve will depend on
the size of the enclosure, filter impedance, open area of vents, and internal blockage (such as
baffles, heatsinks, etc). In the case shown above, the operating point is represented by point
C and would be 80 CFM at a system pressure of about 0.26 in H2O.
If you have any feedback or questions regarding this topic please do not hesitate to contact
us.
Page 2 TDMG Newsletter March 7th, 2012
“Fans are the
primary air
movers ...It is
important to
understand how
they work and
what the fan curve
means…
Volume 2, Issue 1
Fans and Fan Curves
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The BDC issued an
interesting economic letter
last month discussing the
performance of the
Canadian economy in 2011
and the outlook for 2012.
Some of the concerns
reflected in this paper are
common themes such as
the European austerity
measures. But there is
some very interesting
information regarding the
C a n a d i a n a n d U S
economies. In particular,
since Canada’s largest
trade partner is the US, any
positive outlook in the US
should likely mean positive
impact to the Canadian
economy as well.
The most recent data from
the US is encouraging with
job creation at a rate of
approximately 200,000 jobs
per month over the last 5
months. The housing
market is still very fragile,
but sales of existing homes
and single family home
starts have gone up for 3
straight months now. At the
same time, 2011 retails
sales have increase by
7.7% over 2010 and
although the consumer
confidence index fell in
January, there is hope that
things will continue to move
in a positive direction, albeit
slowly.
With respect to Canada,
the economic letter covers
a number of topics and key
indicators such as GDP,
housing market, interest
rates, oil and loonie, etc
and I would highly
recommend taking a quick
read. Here is a link to that
paper—enjoy.
Should you have any
questions do not hesitate
to call us or e-mail us.
newsletter page. Thanks
for your attention and we
look forward to the next
issue of our newsletter.
We’re looking forward to
getting some feedback
from you on our
newsletter and any
questions you may have
for us. Please feel free
to visit us on our website
and leave us your
comments on our
Volume 2, Issue 1
Give Us Your Feedback
Business Development Bank of Canada (BDC) Economic Letter
TDMG Newsletter March 7th, 2012 Page 3
100 Alexis Nihon, suite 120
St Laurent, QC, H4M 2N6
Phone: 514-381-9115
E-mail: [email protected]
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