Note: Descriptions are shown in the official language in which they were submitted.
WO 2022/231895
PCT/US2022/025483
SUPPLY AIR DUCT WITH INTEGRAL NOZZLES FOR DIFFUSING SUPPLY AIR ALONG
THE LENGTH OF THE SUPPLY AIR DUCT
RELATED APPLICATIONS
This application claims priority from U.S. Utility App. No. 17/242,432, filed
28 April 2021, the disclosure of which is incorporated by reference herein in
its entirety.
FIELD OF THE INVENTION
The present invention relates to heating, ventilation, and air conditioning
(HVAC)
systems and more particularly to a supply air duct used in HVAC systems.
BACKGROUND OF THE INVENTION
Conventional supply air ducts, such as spiral ducts, commonly used today in
commercial
buildings to supply air to a space being heated and cooled have many
disadvantages and
shortcomings. First, insulation is difficult, complicated, and extremely time
consuming. For
example, many of the conventional supply air ducts require cutting and sealing
on site.
Secondly, most conventional supply air ducts rely on independently sourced
diffusers that are
secured to the duct or otherwise communicatively connected with the duct. The
spacing and
location of the diffusers are often haphazardly located with little or no
engineering analysis. This
results in the inefficient mixing of supply air with existing air in the space
being heated or cooled,
all of which leads to a non-uniform diffusion of supply air, hot and cold
spots as well as
temperatures stratification in the space being heated and cooled.
SUMMARY OF THE INVENTION
The supply air duct shown and described herein overcomes these disadvantages
and
shortcomings of conventional supply air ducts. The supply air duct disclosed
is designed to
provide high induction and linear diffusion of the supply air, which means
that the entire or at
least most of the duct system is diffusing air to the space in a uniform
fashion, without the use of
add-on diffusers. The high induction flow means that the continuous duct
linear diffusion pattern
causes the rapid mixture of the supply air with the air in the space, bringing
the space to set
point conditions more quickly than conventional supply air ducts.
The design of the supply air duct entails nozzles in the outer walls of the
duct and
spacing and arranging the nozzles linearly along most of the length of the
duct. In one
embodiment, openings in the outer wall that form the nozzles are sized to
cause jet streams of
supply air to be emitted from the supply air duct. This can lead to a negative
pressure around
the supply air duct and nozzles, which tends to induce existing air in the
space to move towards
the duct and nozzles where the existing air is efficiently mixed with the jet
streams of supply air
being emitted by the duct.
1
CA 03216758 2023- 10- 25
WO 2022/231895
PCT/US2022/025483
In one embodiment, the supply air duct is designed to enhance the mixing of
supply air
and existing air in an open space and generally comprises:
a series of duct sections secured together in end-to-end relationship which
forms the
supply air duct;
the supply air duct configured to contain pressurized supply air and
configured to be
suspended or supported in the open space for heating and cooling the open
space;
an array of nozzles in the outer wall of the supply air duct and configured to
disperse the
pressurized supply air from the supply air duct in the form of an array of jet
streams;
the array of nozzles formed in a generally linear direction along the length
of the supply
air duct and including nozzles arranged in rows and generally uniformly spaced
along the length
of the supply air duct; and
the array of nozzles configured to disperse the pressurized supply air through
the
nozzles and generally uniformly along the length of the supply air duct.
Another embodiment entails a method of dispersing supply air to an open space
for
heating and cooling the open space. The method comprises:
suspending or supporting a supply air duct over the open space;
directing pressurized conditioned supply air into and through the supply air
duct;
dispersing the conditioned supply air from the supply air duct generally
uniformly along
the length of the supply air duct by:
dispersing jet streams of the conditioned supply air from the supply air duct
through an
array of nozzles in the outer wall of the supply air duct; and
wherein the array of nozzles is generally uniformly spaced and extend in a
generally
linear direction along the length of the supply air duct.
Other objects and advantages of the present invention will become apparent and
obvious
from a study of the following description and the accompanying drawings which
are merely
illustrative of such invention.
BRIEF DESCRIPTION OF THE DRAWINGS
Figure 1 is a perspective view of an HVAC system including a supply air duct
and a
return air duct.
Figure 2 is a schematic elevational view illustrating the placement of the
supply air duct
in an upper corner area of the space being heated and cooled.
Figure 2-1 is a side elevational view of a duct section showing an array of
nozzles
employed in the supply air duct shown in Figure 2.
Figure 2-2 is a schematic illustration of a duct section illustrating the area
generally
occupied by the nozzles in the supply air duct shown in Figure 2.
Figure 2A is a schematic elevational view illustrating the placement of the
supply air duct
in an upper center area of the space being heated and cooled.
2
CA 03216758 2023- 10- 25
WO 2022/231895
PCT/US2022/025483
Figure 2A-1 is a bottom view of the duct section employed in the supply air
duct shown
in Figure 2A.
Figure 2A-2 is a schematic illustration of the duct section showing the area
occupied by
the nozzles in the supply air duct shown in Figure 2A.
Figure 2B is a view similar to Figure 2A except that the supply air duct is
provided with
two groups of spaced apart nozzles.
Figure 2B-1 is a bottom view of the duct section employed in the supply air
duct shown
in Figure 2B.
Figure 2B-2 is a schematic illustration of the area occupied by the nozzles in
the supply
air duct shown in Figure 2B.
Figure 2C is a schematic elevational view showing the placement of the supply
air duct
in an upper central area of the space and wherein the supply air duct is
provided with two
groups of nozzles spaced 180 apart.
Figure 2C-1 is a side view of a duct section employed in the supply air duct
shown in
Figure 2C.
Figure 2C-2 is a schematic illustration showing the area occupied by the
nozzles in the
supply air duct shown in Figure 2C.
Figure 3 is a perspective view of an alternative design for the supply air
duct wherein the
diameter of the supply air duct is stepped down towards a remote end thereof.
Figure 4 is a schematic illustration showing the mixing of supply air emitted
by the
nozzles and existing air in the space.
Figure 5A shows two duct sections and a securing band prior to the two duct
sections
being connected.
Figure 5B shows the two duct sections connected together by the securing band.
Figure 6A is a fragmentary sectional view showing portions of the two duct
sections prior
to being coupled together.
Figure 6B is a fragmentary sectional view showing a portion of the two ducts
being
secured together by the securing band.
DESCRIPTION OF EXEMPLARY EMBODIMENTS
With further reference to the drawings, particularly Figure 1, an HVAC system
is shown
therein and indicated generally by the numeral 10. HVAC system 10 comprises a
dedicated
outdoor air system 11 for heating and cooling outside air and directing the
heated or cooled air
into a supply air duct 12. In addition, the HVAC system includes a return air
duct 14.
The focus of this invention is on the supply air duct 12. Supply air duct 12
can be
employed with various types and forms of HVAC systems. Thus, the dedicated
outdoor air
system 11 shown in Figure us just one example of an HVAC unit that can be used
with the
supply air duct 12.
3
CA 03216758 2023- 10- 25
WO 2022/231895
PCT/US2022/025483
Supply air duct 12 includes a plurality of duct sections 12A. Duct sections
12A are
joined end-to-end to form the supply air duct 12. As will be explained later,
when the respective
duct sections 12A are connected end-to-end, an airtight seal is formed.
Likewise, the return air
duct 14 includes a plurality of duct sections 14A that are connected in end-to-
end relationship.
Note in Figure 1 where the return air duct 14 includes a return air inlet 14B
formed in the remote
end of the return air duct.
Supply air duct 12 is designed to disperse supply air generally uniformly
along the length
of the supply air duct. Thus, as seen in the drawings, the supply air is
linearly dispersed along
the length of the supply air duct 12. Furthermore, the supply air duct 12 is a
high induction duct.
By high induction, it is meant that the existing air in the open space below
the exposed supply
air duct 12 is induced to move towards the supply air duct where the existing
air efficiently mixes
with the supply air being dispersed from the duct.
Supply air duct 12 includes an array of nozzles 18 in the outer wall of the
duct. In the
examples shown in the drawings, the nozzles 18 are disposed in rows. In some
examples, the
nozzles may reside in a single row and in other examples the nozzles may be
arranged in a
plurality of rows. The nozzle configuration is not limited to aligned row
configurations. Other
nozzle patterns are contemplated. However, whatever nozzle pattern is
employed, the nozzles
are provided along the length of the supply air duct 12. In the example shown
in Figure 2-1,
there are four rows of nozzles in the outer wall of the supply air duct. In
the example shown in
Figure 2B, the nozzles 18 are grouped into two sets of nozzles with each set
comprising two
rows of nozzles. It is appreciated that the nozzles 18 can be grouped in two
or more sets, and
the spacing between the sets can vary. The nozzles are generally uniformly
spaced with
respect to each other.
Nozzles 18 are formed, in one embodiment, by openings in the outer wall of the
supply
air duct 12. The size or diameter of the openings can vary.
Supply air directed from the HVAC unit 11 into the supply air duct 12 is
pressurized. The
pressure in the supply air duct 12 can vary. The pressure inside the supply
air duct 12 can be
measured in water column and can vary.
Nozzles 18 effectively resist the flow of supply air from the supply air duct
12. Nozzles
18 give rise to a Venturi effect. That is, in the course of restricting the
flow of supply air, the
velocity of the supply air exhausted by the nozzles 18 increases. This results
in the supply air in
the supply air duct 12 being dispersed in jet streams into the open space
being heated or
cooled.
In one embodiment, the nozzles 18 extend continuously along a substantial
length of the
supply air duct 12. The length of the supply air duct is defined to be the
length between the first
and last nozzle or nozzles. This means that the length of the supply air duct
does not include
feed sections extending from the HVAC unit to where the first nozzles are
located. In some
embodiments, the nozzle pattern formed in the supply air duct may not be
continuous. For
4
CA 03216758 2023- 10- 25
WO 2022/231895
PCT/US2022/025483
example, in some cases, not all of the duct sections 12A in the supply air
duct include nozzles.
For example, in some embodiments, the nozzles may be provided in every other
duct section
12A. The nozzle pattern should extend over a substantial length of the supply
air duct. It is
preferable that at least 50% of the length of the supply air duct include a
nozzle pattern for
dispersing supply air.
Because the nozzles 18 emit a jet stream of supply air, a negative pressure is
generated
immediately adjacent the exterior side of the nozzles. That is, there is a
small pressure
differential that exists between the open space generally and the area
immediately adjacent the
nozzles 18. This gives rise to the induction feature of the supply air duct
12. Because of this
negative pressure, existing air in the open space tends to be induced or swept
upwardly toward
the supply air duct 12 and particularly to areas adjacent the nozzles 18. This
is schematically
shown in Figure 4. Here the existing air is represented by arrows whose tails
are dotted while
the supply air is represented by full arrows. This is one example of a flow
pattern for the supply
air and the existing air. These flow patterns can vary depending on numerous
factors, such as
the location of the supply air duct 12 in the open space, the arrangement of
nozzles in the
supply air duct, the spacing and size of the openings that form the nozzles
18, as well as other
factors. In any event, this results in the efficient mixing of existing air
with the jet streams of
supply air being emitted by the nozzles 18. This efficient mixing of supply
air with existing air in
the space being heated or cooled provides a uniform diffusion of supply air
into the open space
and avoids hot and cold spots, as well as temperature stratification in the
space being heated or
cooled.
Supply air duct 12 is designed to be employed in an open ceiling environment
where the
duct is exposed in the open space. As the drawings indicated, the supply air
duct can be
located at various locations in the open space. For example, see Figures 2,
2A, 2B and 2C. In
these cases, the supply air duct 12 is suspended or supported in an upper
portion of the open
space. In Figure 2, the supply air duct 12 is supported in an upper comer area
of the open
space. In this particular example, the nozzle pattern includes four rows of
nozzles. See Figure
2-1. The nozzle pattern extends approximately 450 around the duct. Note in
Figure 2 where the
nozzle pattern is located generally in the 4:00 ¨ 5:00 o'clock position such
that the jet streams of
supply air are directed generally outwardly and slightly downwardly from the
supply air duct 12.
In Figure 2A, the supply air duct 12 is disposed in an upper center area of
the open
space. In this example, the nozzle pattern includes four rows and are provided
over
approximately a 45 of the supply air duct. See Figures 2A-1 and 2A-2. Note in
the Figure 2A
example where the nozzle pattern is generally centered at the 6:00 o'clock
position such that
the jet streams of supply air are directed downwardly.
Turning to the example shown in Figure 2B, the supply air duct 12 is again
located in the
upper center of the open space. However, in this example, the supply air duct
is provided with
5
CA 03216758 2023- 10- 25
WO 2022/231895
PCT/US2022/025483
two sets or groups of nozzles 18. See Figure 2B-1. Note in Figure 2B where the
jet streams of
supply air are directed generally downwardly and slightly outwardly from the
two sets of nozzles.
The example shown in Figure 2C is similar in some respects to that shown in
Figure 2B.
Here again, the supply air duct 12 is disposed in an upper central portion of
the open space.
Supply air duct 12 is provided with two sets or groups of nozzles 18. These
two sets of nozzles
are generally separated by 1800. As seen in Figure 2C, the two sets of nozzles
provide an
array of jet streams of supply air from both sides of the supply air duct 12.
That is, the jet
streams are directed generally horizontally from opposite sides of the supply
air duct 12.
The open space containing the supply air duct 12 will include what is termed
an
occupied area or space (occupiable area) where people work, congregate, move
through, etc.
The velocity of the supply air emitted by the nozzles 18 is typically greater
than what is
appropriate for the occupiable area. Thus, the HVAC system 10 and particularly
the supply air
duct 12 is designed to assure that the velocity of the supply air reaching the
occupiable area is
below a selected threshold. In one example, the threshold is approximately 50
feet per minute.
So, in this case, the openings forming the nozzles 18 are particularly sized,
spaced and
arranged with respect to the HVAC system as a whole to assure that the
velocity of the supply
air reaching the occupiable area is less than the selected threshold which in
this example is 50
feet per minute. Figures 2, 2A, 2B and 2C show the supply air being emitted by
the nozzles 18.
But the supply air in each case is surrounded by a dotted line envelope. In
this example, the
velocity of the supply air outside of this envelope should be less than the
threshold value.
Turning to Figures 5A and 5B, details of the duct sections 12A are shown. Duct
sections
12A can be constructed of various materials. In one embodiment, stainless
steel is employed.
Each duct section includes a main cylindrical body 12A1 and a pair of
outwardly projecting
flanges 12A2 and 12A3. At least some of the duct sections 12A have an integral
gasket 20
incorporated into the duct section when fabricated. The term "integral gasket"
means that the
gasket is incorporated into the duct section during fabrication of the duct
section and not at the
installation site. This alleviates problems associated with installing or
incorporating a gasket
during on-site installation. Gasket 20 is secured to the outer side of at
least one of the flanges
12A2 or 12A3. In one embodiment, both flanges 12A2 and 12A3 include the
integral gasket 20.
Various materials can be used for the gasket 20. In a preferred embodiment,
the gasket
comprises an ethylene propylene cliene monomer rubber (EPDM) foam gasket. EPDM
is blended
with neoprene and styrene-butadiene rubber (SPR) to create a foam that offers
excellent
resistance to water and wear.
In one embodiment, one duct section 12A having the integral gasket 20 is
connected to
another duct section that does not include the integral gasket. See Figure 5A.
The duct section
12A on the left includes the integral gasket 20 but the duct section to the
right does not include
the integral gasket. In any event, the two duct sections are brought together
and the flange
12A2 of the rightmost duct section is butted against the gasket 20 secured to
flange 12A2 on
6
CA 03216758 2023- 10- 25
WO 2022/231895
PCT/US2022/025483
the leftmost duct section. To secure the two duct sections together, a V-band
22 is employed.
As shown in Figures 6A and 6B, the V-band spans the two flanges and the gasket
20 and is
tightly secured around the joint formed by the two flanges 12A2 and the gasket
20. As seen in
the drawings, flanges of the two duct sections are inside the V-band 22. Once
the V-band 22 is
disposed around the joint, it is tightened so as to effectively secure one
duct section to another
duct section.
In many instances, the diameter of the supply air duct 12 is constant
throughout its
length. There may be cases where it is desirable to step down the diameter of
the supply air
duct 12 along its length. One example of this is shown in Figure 3 where the
supply air duct 12
includes three duct sections of one diameter and three duct sections of
another diameter. This
can be helpful in particularly designing the supply air duct for a particular
application and in
cases where varying the diameter can facilitate a final design that emits a
more generally
uniform distribution of supply air along the length of the supply air duct.
There are many advantages of supply air duct 12. Supply air emitted from the
supply air
duct is more laminar and evenly distributed into the open space being heated
or cooled.
Further, the supply air duct is a high induction supply air diffuser. High
induction means that the
continuous linear diffusion pattern causes rapid mixture of the supply air
with the existing air in
the open space, bringing the open space to setpoint conditions much more
quickly than
conventional supply air ducts. Supply air duct 12 also has enhanced
aesthetics, particularly
when constructed of stainless steel. This highly finished appearance for open
ceiling or
industrial use makes the supply air duct of the present invention appealing in
restaurants,
breweries, and commercial and industrial buildings.
Moreover, the duct sections 12A are field-ready for installation at the
installation site. No
metal cutting is required and there is no requirement to install seals or
gaskets. This is because
the individual duct sections 12A come with an integral gasket. Thus, it is
just a matter of
aligning respective duct sections 12A together and coupling them together with
a V-band 22.
The term "configured to" is used herein and in the claims. The term
"configured to"
means "designed to". It does not mean "capable of" or "adapted to". Hence, the
use of
"configured to" with reference to a component or element of the invention
means that such
component or element is specifically designed to perform a recited function.
The present invention may, of course, be carried out in other specific ways
than those
herein set forth without departing from the scope and the essential
characteristics of the
invention. The present embodiments are therefore to be construed in all
aspects as illustrative
and not restrictive and all changes coming within the meaning and equivalency
range of the
appended claims are intended to be embraced therein.
7
CA 03216758 2023- 10- 25
