Tdmg vol 3-iss-1_rev1_final

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.


“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




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


100 Alexis Nihon, suite 120

St Laurent, QC, H4M 2N6

Phone: 514-381-9115

E-mail: [email protected]


https://www.bdc.ca/EN/Documenthttps:/www.bdc.ca/EN/Documents/doc_corpo/economic_letter/EconomicLetter_feb2012_EN.pdf



Tdmg vol 3-iss-1_rev1_final

Technology

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