Air conditioning unit
Field of the invention
[0001] The present invention relates to an air conditioning device, and a method
for air conditioning a confined space5 .
Background of the invention
[0002] Air conditioning devices integrated into the ceiling of confined spaces are
well known. Among these devices, a first type relates to static-type cold beams, in which
10 the air passes through a cooled exchanger, the air flow being created by simple
convection.
[0003] A second type of cold beam relates to dynamic-type cold beams in which a
flow of fresh air coming from outside the confined space is mixed with secondary air
coming from the room to be air conditioned. In this type of device, the primary air is
15 injected at high pressure into nozzles, causing suction of secondary air by means of the
Venturi effect. This type of device has many advantages. The first advantage is that the
injection of fresh air makes it possible to refresh the air in the confined space. The
primary fresh air may further be dried so as to avoid condensation phenomena. Lastly,
the secondary air passes into a cooled heat exchanger before mixing, which increases
20 the cooling capacity of the whole device.
[0004] However, these dynamic cold beams have other drawbacks that the
present invention will seek to reduce. For instance, this type of device is generally noisy.
In fact, for optimal operation, the ratio between the intake of primary fresh air and the
recirculation of secondary air should be approximately 1:7. However, to obtain such a
25 ratio purely by means of the Venturi effect, the pressure of the primary air and its speed
in the nozzles cause noise that is difficult to bear continuously. Furthermore, these
dynamic beams generally work with a suboptimal primary air/secondary air ratio,
generally comprised between 1:2 and 1:6. This low ratio involves an air renewal in the
medium exceeding what is necessary, involving higher energy consumption than what is
30 strictly necessary.
WO 2014/135406 2 PCT/EP2014/053677
[0005] European patent application EP 1,319,901 discloses a device comprising
two Venturi-type devices positioned in series making it possible to mix so-called primary
fresh air with so-called secondary recirculated air. Nevertheless, the inlet pressure of the
second Venturi of the device is greatly insufficient, and does not make it possible to
achieve a sufficient secondary air suction, and the ratio between secondary air an5 d
primary air is still insufficient.
Aim of the invention
[0006] The present invention aims to propose a dynamic cold beam air
10 conditioning device, having reduced noise while offering an improved primary
air/secondary (recirculated) air ratio.
[0007] According to certain preferred embodiments of the invention, it also aims to
improve the thermal comfort related to the use of the device according to the invention.
15 Summary of the invention
[0008] The present invention relates to an air conditioning device comprising a
primary air intake pipe (chamber) connected to the inlet of a first Venturi-type device
(induction unit) whereof the suction communicates with a first secondary air intake pipe
20 (chamber), the outlet of the first Venturi-type device communicating with the inlet of a
second Venturi-type device (induction unit) whereof the suction is connected to a
second secondary air intake pipe (chamber) comprising a main heat exchanger.
[0009] The outlet of this device communicates directly or indirectly with the room
to be air conditioned.
25 [0010] Preferably, the first Venturi-type device comprises a primary air inlet nozzle
comprising a diameter restriction at its free end, said free end emerging in a suction
chamber communicating with the first secondary air intake pipe, said suction chamber
comprising an outlet orifice across from the outlet of said inlet nozzle, said outlet orifice
communicating with the inlet of the second Venturi-type device.
WO 2014/135406 3 PCT/EP2014/053677
[0011] Advantageously, the second Venturi-type device comprises an intake (or
mixing) chamber, the intake chamber having a section at least twice as large as the
outlet orifice of the suction chamber of the first Venturi-type device.
[0012] Advantageously, the second Venturi-type device comprises a plate pierced
with orifices, said plate separating the intake chamber communicating with the outlet 5 t of
the first mixing device and a mixing chamber communicating with the second secondary
air intake pipe, said orifices producing, during use, a Venturi effect suctioning the
secondary air from the secondary air intake pipe.
[0013] Preferably, the device according to the invention comprises an adjustable
10 gate or valve making it possible to inject primary air directly at the inlet of the second
Venturi-type device, downstream from the first Venturi-type device, so as to be able to
regulate the total mixture ratio between the primary air and the secondary air.
[0014] Advantageously, the first secondary air intake pipe comprises a second
heat exchanger making it possible to cool the secondary air during use.
15 [0015] Preferably, the heat exchanger(s) comprise vertical fins, and a device
discharging condensation at the bottom thereof.
[0016] A second aspect of the invention relate to a façade, a façade element or an
element allowing access to the façade of a building comprising an air conditioning
device according to any one of the preceding claims.
20 [0017] Advantageously, the façade according to the invention comprises two walls
separated by a ventilation space, the first and second secondary air intake pipes
communicating with said ventilation space.
[0018] The second wall may be of the curtain or helioscreen type, or preferably,
the façade will be of the active façade type.
25 [0019] A third aspect of the invention relates to a method for air conditioning a
confined space comprising the following steps:
a. drawing in outside air, called primary air, and bringing it to a predetermined
pressure;
b. injecting said primary air into a Venturi-type device, suctioning and mixing
30 air from the confined space, called secondary air, with the primary air, the
WO 2014/135406 4 PCT/EP2014/053677
secondary air passing, before mixing, into a first heat exchanger regulated to a
setpoint temperature thus obtaining a first air mixture;
c. injecting the first air mixture into a second Venturi-type device, suctioning
and mixing secondary air with said first air mixture, the secondary air passing,
before mixing, into a second heat exchanger regulated to a setpoint temperatu5 re;
d. reinjecting the obtained air mixture into the confined space.
[0020] According to preferred embodiments of the invention, the air conditioning
method according to the invention further comprises one or a suitable combination of
10 several of the following features:
 the first air mixture is compressed in a mixing chamber communicating with
the outlet orifice of the suction chamber, said intake chamber having a section at least
twice as large as the outlet orifice of the suction chamber, so as to cause compression
of the first air mixture;
15  said predetermined pressure is comprised between 100 and 1,000 Pa,
preferably between 300 and 500 Pa;
 the ratio between the intake of primary air and secondary air in the first
mixing device is comprised between 0.7 and 2.5, preferably between 0.9 and 2.5,
advantageously greater than 1.6;
20  the flow ratio between the intake of the first air mixture and secondary air in
the second mixing device is comprised between 2 and 4;
 the pressure of the first air mixture at the inlet of the second Venturi device
is comprised between 50 and 200 Pa, preferably between 70 and 150 Pa;
 the secondary air flows in a ventilated space between two walls of an
25 active façade before being taken into the first and second mixing chambers;
 the primary air withdrawn in step (a) is brought to a predetermined
temperature before being injected into said first Venturi-type device.
Brief description of the figures
30
WO 2014/135406 5 PCT/EP2014/053677
[0021] Figure 1 shows a stripped down view of an examplary air conditioning
device according to the invention.
[0022] Figure 2 shows a side sectional view along plane AA” of figure 1.
[0023] Figure 3 shows a side sectional view along plane BB’ of figure 1.
[0024] Figure 4 shows a sectional side view along plane BB’ of figure 1, th5 e
device comprising a bypass in the open position.
Detailed description of the invention
[0025] The present invention relates to an air conditioning device 10 of the
10 dynamic cold beam type comprising a double induction module for secondary air,
making it possible, during use, to increase the ratio between the flow rate of outside
primary air 18, 22 injected into the room to be air conditioned and the flow rate of
secondary recirculated air 16, 17. The use of two Venturi-type induction modules,
arranged in series, makes it possible to reduce noise, without increasing the necessary
15 primary air pressure, while making it possible to increase the secondary air flow rate for
a given primary air flow rate.
[0026] A Venturi-type device, or induction device, refers to any type of device in
which a first flow of air is accelerated by a section restriction of the fluid path causing
suctioning of a second air flow by means of the Venturi effect. It typically involves a
20 device of the ejector or eductor type, in the form of nozzles or diaphragms, or more
complex devices comprising an inlet nozzle, a suction chamber and an outlet nozzle. A
Venturi device inlet refers to the inlet for the first flow of air.
[0027] Preferably, the first Venturi device, into which the air conditioned air 18
coming from an external air conditioning battery is injected, comprises an injection
25 nozzle 3 comprising a restriction at its free end. This nozzle opens into a suction
chamber 2 communicating with a secondary air pipe 9 (coming from the room to be air
conditioned). The suction chamber 2 also comprises an outlet orifice 15 across from the
outlet of the injection nozzle 3. This orifice 15 will advantageously be extended by a
profiled ejection nozzle, so as to reduce the turbulence and the noise generated by that
30 turbulence.
WO 2014/135406 6 PCT/EP2014/053677
[0028] Preferably, the first Venturi device is dimensioned such that the flow ratio
between the primary air 18 and the air 17 induced by the first Venturi device is
comprised between 0.7 and 1.5.
[0029] Advantageously, the second Venturi-type device comprises an intake
chamber, the intake chamber having a section that is at least twice as large as the outle5 t
orifice of the suction chamber. The increased section of the intake chamber allows the
compression of the first air mixture, which considerably improves the air induction by the
second Venturi-type device.
[0030] The temperature of the primary air 18 will preferably be comprised
10 between 14 and 18°C as a function of the required cooling power. This primary air 18
will further have a controlled humidity level so as to reduce the relative humidity of the
room, in order to prevent any condensation phenomenon. Lastly, the pressure of the
primary air 18 will preferably be comprised between 300 and 500 Pa, ideally
approximately 400 Pa.
15 [0031] The pressures used in this description are of course relative pressures with
respect to the ambient atmospheric pressure (pressure difference relative to the
atmosphere).
[0032] The second induction device will preferably assume the form of a wall 14
(plate) separating the intake or mixing chamber 4, into which opens the outlet 15 of the
20 first Venturi device, from a second mixing chamber 6, into which opens a second
secondary air intake pipe 11. This second intake pipe comprises a main heat exchanger
8 making it possible to effectively cool the secondary air flow 16 induced by the second
Venturi device.
[0033] The wall 14 will comprise orifices 5 communicating between the first mixing
25 chamber 4 and the second mixing chamber 6. These orifices 5 will either assume the
form of simple diaphragms, or of nozzles causing an increase in the speed of the air,
and thus a Venturi effect suctioning the secondary air 16 through the primary heat
exchanger 8.
[0034] The pressure in the first mixing chamber 4 is preferably comprised
30 between 50 and 100 Pa, so as to reduce the noise generated by the device.
WO 2014/135406 7 PCT/EP2014/053677
[0035] The flow ratio between the intake of secondary air 16 of the second Venturi
device and the outlet 19 of the first induction device is preferably comprised between 2
and 4, bringing the total ratio between primary air and air induced by the two Venturi
devices to a value greater than approximately 4, preferably greater than 6, and even
advantageously greater than 75 .
[0036] Advantageously, a bypass valve 20, 21 between a primary air distribution
pipe 12 and the first mixing chamber 4, so as to be able to increase the primary air
injection 22 (primary air/secondary air ratio), for example when an unusual number of
occupants are in the room. Figure 4 shows the operation of the device when the valve
10 21 is in the open position. In that case, a primary air flow 22 is admitted directly into the
inlet chamber 4. In that case, preferably, the first secondary air intake pipe will include a
non-return device (not shown), for example in the form of a gate preventing a reverse
flow of primary air.
[0037] A secondary heat exchanger 7 can advantageously be placed on the fluid
15 path of the secondary air flow 17 upstream from the suction of the first Venturi-type
device. This secondary heat exchanger 7 makes it possible on the one hand to increase
the total power of the device, and on the other hand to regulate the humidity of the
mixture in the first chamber 4.
[0038] Preferably, the setpoint temperature of the heat exchangers 7, 8 will be a
20 temperature comprised between 14 and 20°C, so as to avoid condensation while
offering sufficient cooling power. This setpoint temperature will be adapted as a function
of the necessary power and the relative humidity of the secondary air.
[0039] Preferably, the air conditioning module (device) of the invention is
integrated into the façade, above the windows, so as to induce a secondary air flow in
25 front of the hot zone caused by the window of the building. This hot zone may
advantageously be optimized by using devices simulating an active façade, such as
curtains or helioscreens.
[0040] Advantageously, the air conditioning module according to the invention is
integrated into an active façade comprising a ventilated empty space comprised
30 between two walls, the intake pipes 9, 11 for secondary air being connected to said
ventilated empty space. In that case, the air conditioned secondary air circulation
WO 2014/135406 8 PCT/EP2014/053677
between the two walls makes it possible to cool the inner wall, and thus to improve the
comfort of the air conditioned room, the walls of the room having a lower temperature,
which improves comfort.
[0041] The arrangement in the façade makes it possible to use vertical
exchangers, which allows an easy collection and discharge of any condensation on th5 e
fins of those exchangers.
[0042] The integration of the air conditioning module of the invention into the
façade also makes it possible to reduce the bulk, the primary air and cold water
channels easily being able to be integrated into said facade, avoiding having to integrate
10 the beams into the ceiling, which poses installation and maintenance difficulties.
[0043] The device according to the invention may advantageously incorporate one
or more charcoal filters. Furthermore, the inner surfaces of the mixing chambers and
Venturi devices may be covered with catalytic paint comprising Ag ions or photocatalytic
titanium oxide paint making it possible, through the use of UV light sources, to reduce
15 the volatile organic compounds present in the room.
[0044] The primary fresh air can also be taken directly from the façade using a
fan, the humidity regulation then being done directly along the heat exchangers, using a
condensate tub placed below the heat exchangers.
20 Example
[0045] One examplary embodiment of a device 10 according to the invention is
shown in figures 1 to 4. This device is integrated into an active façade in which the air is
heated by the action of the sun in a ventilated empty space comprised between two
windows. The air in the ventilated empty space communicates with the room to be air
25 conditioned by the bottom of the active window, so as to increase the natural convection
through the device, thereby further improving the secondary air flow rate.
[0046] In this device, a distribution pipe 12 placed on the façade brings in the
conditioned primary air. The air in this pipe is kept at a pressure of 410 Pa and a
temperature of approximately 14°C. The humidity of this primary air is approximately
30 90%. This air is conditioned using a first centralized battery for the entire building. The
WO 2014/135406 9 PCT/EP2014/053677
energy consumption of this first battery, per air conditioning module, is approximately
283 W for an outside temperature of 32°C and a relative humidity of 50%.
[0047] This air conditioned primary air 18 is brought in through a distribution
chamber 1 to a nozzle 3 opening into the first suction chamber 2. The flow rate of air
conditioned primary air in each façade module is 25 m3/5 h.
[0048] The air conditioned primary air flow rate at the outlet of the nozzle 3
suctions secondary air 17 through an orifice 13. This secondary air coming from the
intake pipe 9 passes in a heat exchanger 7 before being mixed with the primary air 18 in
the suction chamber 2. The temperature of the cooling water in this exchanger is 12°C
10 at the inlet and 14°C at the outlet. The power consumed by this battery is approximately
146 W. The flow rate of secondary air 17 comes from an active façade, and enters the
heat exchanger at a temperature of 34°C and 36% relative humidity. The flow rate of
secondary air 17 in this first heat exchanger 7, induced by the primary air flow, is 25
m³/h.
15 [0049] The mixture 19 of primary air 18 and secondary air 17 induced by the first
Venturi device is injected into a chamber 4 delimited by a wall 14 pierced with orifices 5
opening into a second suction chamber 6. Secondary air 16 enters that second suction
chamber 6 through a second heat exchanger 8. The secondary air suctioned by the pipe
11 once again comes from the active façade and has the same inlet characteristics as
20 the air admitted by the pipe 9. The flow rate of secondary air induced in this second
Venturi device is approximately 150 m3/h.
[0050] One therefore obtains an air flow rate at the outlet of the device of 200
m3/h, for a primary air flow rate of 25 m3/h, i.e., a multiplicative factor of 8 (or a 1:7 ratio).
The outlet air in this example is at 18°C, for an ambient temperature of 26°C. This
25 conditioned air is ejected via the orifice 23.
[0051] A gate 20, 21 makes it possible, as needed, to bypass the first induction
unit (Venturi device), so as to increase the reduce the multiplicative factor of the device.
During operation with the gate 21 opened, the primary air flow rate goes to 50 m3/h,
while the flow rate of secondary air induced in the second induction unit remains
constant at 150 m330 /h, going from a multiplicative factor of 8 to 4.
WO 2014/135406 10 PCT/EP2014/053677
[0052] Injecting the secondary air in a forced manner into the ventilated empty
space of the active façade makes it possible to avoid an exaggerated increase in the
temperature of the inner walls of the premises, which increases the feeling of comfort for
occupants.
[0053] The two heat exchangers 7, 8 being adjacent, in practice, it is possible t5 o
use a single exchanger with a wall separating the two pipes. Nevertheless, it may be
interesting to adjust these two heat exchangers differently, so as to avoid any
condensation in the first mixing chamber.
[0054] The dimensions of the module of the example are compatible with the
10 dimensions of windows typically used in the building, in the case at hand, in this
example, the width of the second heat exchanger is 1 m, and 25 cm for the first
exchanger. The height of the first and second heat exchangers is 29 cm, while the total
height of the module (including the distribution pipe 12 for the primary air) is 60 cm.

CLAIMS
1. An air conditioning device (10) comprising a primary air intake pipe (1)
connected to the inlet of a first Venturi-type device whereof the suction communicates
with a first secondary air intake pipe (9), the outlet of the first Venturi-type dev5 ice
communicating with the inlet of a second Venturi-type device whereof the suction is
connected to a second secondary air intake pipe (11) comprising a main heat exchanger
(8), the first Venturi-type device comprising a primary air inlet nozzle (3) comprising a
diameter restriction at its free end, said free end emerging in a suction chamber (2)
10 communicating with the first secondary air intake pipe (9), said suction chamber (2)
comprising an outlet orifice (15) across from the outlet of said inlet nozzle, said outlet
orifice (15) communicating with the inlet of the second Venturi-type device,
characterized in that the second Venturi-type device comprises an intake chamber (4),
said intake chamber (4) having a section at least twice as large as the outlet orifice (15)
15 of the suction chamber (2).
2. The air conditioning device (10) according to claim 1, wherein the second
Venturi-type device comprises a plate (14) pierced with orifices (5), said plate separating
the intake chamber (4) communicating with the outlet (15) of the first mixing device and
a mixing chamber (6) communicating with the second secondary air intake pipe (11),
20 said orifices (5) producing, during use, a Venturi effect suctioning the secondary air.
3. The air conditioning device (10) according to either one of the preceding
claims, wherein the first secondary air intake pipe (9) comprises a secondary heat
exchanger (7).
4. The air conditioning device (10) according to any one of the preceding
25 claims, wherein the heat exchanger(s) comprise vertical fins, and a device discharging
condensation at the bottom thereof.
5. The air conditioning device (10) according to any one of the preceding
claims, wherein an adjustable gate makes it possible to inject primary air directly at the
inlet of the second Venturi-type device, downstream from the first Venturi-type device,
30 so as to be able to regulate the total mixture ratio between the primary air and the
secondary air.
WO 2014/135406 12 PCT/EP2014/053677
6. A façade comprising an air conditioning device (10) according to any one
of the preceding claims.
7. The façade according to claim 6, comprising two walls separated by a
ventilation space, the first and second secondary air intake pipes being connected to
said ventilation space5 .
8. A method for air conditioning a confined space comprising the following
steps:
a. drawing in outside air (18), called primary air, and bringing it to a
predetermined pressure;
10 b. injecting said primary air (18) into a Venturi-type device, suctioning from a
suction chamber (2) and mixing air from the confined space, called
secondary air (17), with the primary air, the secondary air passing, before
mixing, into a first heat exchanger (7) regulated to a setpoint temperature
thus obtaining a first air mixture (19);
15 c. injecting the first air mixture (19) into a second Venturi-type device,
suctioning and mixing secondary air (16) with said first air mixture (19), the
secondary air passing, before mixing, into a second heat exchanger (8)
regulated to a setpoint temperature;
d. reinjecting the obtained air mixture into the confined space;
20 characterized in that the first air mixture (19) is compressed in a mixing chamber (4)
communicating with the outlet orifice (15) of the suction chamber (2), said intake
chamber (4) having a section at least twice as large as the outlet orifice (15) of the
suction chamber (2), so as to cause compression of the first air mixture (19).
25 9. The method according to claim 8, wherein said predetermined pressure is
comprised between 100 and 1,000 Pa.
10. The method according to either one of claims 8 and 9, wherein the ratio
between the intake of primary air and secondary air in the first mixing device is
comprised between 0.7 and 2.5.
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11. The method according to any one of claims 8 to 10, wherein the flow ratio
between the intake of the first air mixture and secondary air in the second mixing device
is comprised between 2 and 4.
12. The method according to any one of claims 8 to 11, wherein the pressure
of the first air mixture at the inlet of the second Venturi device is comprised between 55 0
and 100 Pa.
13. The method according to any one of claims 8 to 12, wherein the secondary
air flows in a ventilated space between two walls of an active façade before being
suctioned through the heat exchangers (7, 8).
10 14. The method according to any one of claims 8 to 13, wherein the primary air
drawn in in step (a) is brought to a predetermined temperature before being injected into
said first Venturi-type device.