Filtration device for a ventilation system and ventilation system including such device

Abstract

The present invention concerns a filtration device (2) for a ventilation system (1,40) capable of introducing into the indoor environment (11) a supply air flow rate ( Pimm) comprising a recirculation air flow rate (Pric) from the indoor environment (ID and a renewal air flow rate ( Prin) from the outdoor environment. The filtration device comprises: first ventilation means (24), first filtration means (25) and processing and control means (26) configured to: receive at least a first input signal (S1), receive at least a second input signal (S2) and generate, on the basis of the first input signal (S1) and the second input signal (S2), a first control signal (C1) for the first ventilation means (24) and a second control signal (C2) for the second ventilation means (35) of the ventilation system (1,40), said second ventilation means being capable of generating the recirculation air flow rate or the supply air flow rate; the first and the second control signal (C1, C2) are correlated with respective reference values of the renewal air flow rate (Prin) and the recirculation air flow rate (Pric) or the supply air flow rate ( Pimm).

Description

[0001] FILTRATION DEVICE FOR A VENTILATION SYSTEM AND VENTILATION SYSTEM INCLUDING SUCH DEVICE

[0002] Cross-Reference to Related Applications

[0003] This Patent Application claims priority from Italian Patent Application No . 102025000001395 filed on January 27, 2025, the entire disclosure of which is incorporated herein by reference .

[0004] Technical Field

[0005] The present invention relates to an air filtration device . The invention has a preferred but not exclusive application in ventilation systems, wherein reference will be made below without thus losing generality.

[0006] The invention also relates to a ventilation system comprising such device .

[0007] Prior Art

[0008] Over the last few decades, atmospheric pollution has increased considerably, negatively influencing the quality of the air that we breathe .

[0009] This is the reason why air quality is currently a priority at both companies and in residential areas, particularly in indoor environments such as offices or homes .

[0010] In this regard, ventilation systems play a fundamental role in countering the high concentration of pollutants in indoor environments .

[0011] In particular, correct management of the flow rates by the ventilation system guarantees a constant exchange of the air, avoiding stagnant air and limiting the proliferation of bacteria, viruses or other harmful particles .Furthermore, thanks to regulation of the air flow rates, it is possible to optimise energy consumption: an optimally sized system can modulate the air flow based on the environmental conditions, increasing the flow rate when necessary or reducing it to avoid waste .

[0012] For example, document US8147302B2 describes a ventilation system comprising a plurality of sensors located in different positions in the system, in which such sensors are configured to detect contaminants in the air in the various environments connected to the system and to transmit such values to a single processing unit which, in response to such values, is configured to generate one or more signals of air quality parameters and to provide one or more of such signals to a control device configured to control the volume of the air flow supplied into the various environments .

[0013] Another example of a ventilation system is described in document FR3063538A1, which describes a ventilation system for treatment of the air in an environment .

[0014] In particular, the aforesaid system comprises various regulation valves for regulating the air flow rate that allow the fraction of preheated fresh air flow to be supplied into an environment connected to such system to be regulated.

[0015] However, the ventilation systems currently marketed have various problems .

[0016] In the first place, these systems are not capable of ensuring an optimal quality of the air in the indoor environment when the quality of the external air varies .

[0017] Furthermore, there is a need in the sector to have flexible and modular solutions, which can be adapted to applications in different contexts, such as work or public environments, privatehomes or hospitality structures .

[0018] An obj ect of the present invention is therefore to obtain a filtration device, particularly for a ventilation system, and a ventilation system provided with such device, which allow the aforementioned problems to be overcome .

[0019] Summary of the Invention

[0020] According to the invention, this obj ect is achieved by a filtration device as claimed in claim 1.

[0021] The present invention also relates to a ventilation system as claimed in claim 5.

[0022] The dependent claims describe particular embodiments of the invention .

[0023] Brief Description of the Drawings

[0024] For a better understanding of the present invention, a preferred embodiment is described below, by way of non-limiting example and with reference to the appended drawings, in which:

[0025] • Figure 1 shows schematically a ventilation system according to an embodiment of the present invention;

[0026] • Figure 2 shows schematically a first filtration device of the system of Figure 1 ;

[0027] • Figure 3 shows schematically a second filtration device of the system of Figure 1 ; and

[0028] • Figure 4 shows schematically the ventilation system of Figure 1 according to a further embodiment of the present invention .

[0029] Detailed Description of the Invention

[0030] In Figure 1, the number 1 denotes, in its entirety, a ventilation system according to an embodiment of the present invention.

[0031] The ventilation system 1 comprises a first filtration device 2having an inlet 3 connected by an inlet duct 4 to an external air intake 5 and an outlet 6 connected by an outlet duct 7 to a first node 8, in turn connected by a supply duct 9 to an air intake inlet 10 in an indoor environment 11.

[0032] The system 1 further comprises an intake duct 12 communicating at one end with the indoor environment 11 through an intake air inlet 14 and connected at an opposite end to a second node 15, in turn connected to an expulsion duct 16 communicating with the outside through an expulsion outlet 17.

[0033] Lastly, the system 1 comprises a recirculation duct 18 which connects the first node 8 and the second node 15 to each other .

[0034] The system 1 further comprises a second filtration device 19 arranged along the recirculation duct 18.

[0035] The second filtration device 19 has an inlet 20 communicating with the indoor environment 11 and an outlet 21 connected to the first node 8 by means of the recirculation duct 18.

[0036] The ventilation system 1 comprises at least a first detection sensor 22 for detecting a concentration of particulate matter in the outdoor air, and at least a second sensor 23 for detecting a parameter correlated with the air quality in the indoor environment 11, preferably the carbon dioxide concentration.

[0037] Preferably, the ventilation system 1 also comprises at least a third detection sensor 37 for detecting a concentration of volatile organic compounds (VOC) in the indoor environment 11.

[0038] The third sensor 37 can also be used to detect an equivalent carbon dioxide concentration based on the concentration of VOC .

[0039] Preferably, the first sensor 22 is arranged inside or in proximity to the external air intake 5.Advantageously, the second sensor 23 is arranged inside or in proximity to the indoor environment 11, preferably at one end of the intake duct 12.

[0040] As shown in Figure 2, the first filtration device 2 comprises :

[0041] • a first ventilator 24 configured to draw in a renewal air flow rate Prin from the outside environment;

[0042] • a first filtration unit 25 configured to filter the renewal air flow rate Prin;

[0043] • a processing and control unit 26 configured to :

[0044] - receive from the first sensor 22 at least a first input signal SI correlated with the particulate concentration detected, expressed, for example, in pg / m3;

[0045] - receive from the second sensor 23 at least a second input signal S2 correlated with the concentration (or equivalent concentration) of carbon dioxide detected in the indoor environment 11, expressed, for example, in parts per million [ppm] ; and

[0046] - generate a first control signal Cl for the first ventilator 24 based on the first input signal SI and the second input signal S2 .

[0047] The first control signal Cl is correlated with a reference value of the renewal air flow rate Prin determined by the processing and control unit 26 as described below.

[0048] Preferably, the first filtration unit 25 comprises at least one filter, for example a mechanical filter, which comprises porous materials capable of creating a physical barrier to particles having a predetermined size .

[0049] Preferably, the first filtration unit 25 comprises three filters 27, 28, 29 arranged in series, each designed on the basis of the size of the particles to be filtered. In particular, the first filter 27 is a coarse filter for filtering large-sizedparticles, for example dust, the second filter 28 is a medium filter for filtering intermediate-sized particles, for example fine dust, and the third filter 29 is a fine filter for filtering the smallest particles, for example pollens or mould spores .

[0050] The invention also contemplates the possibility of equipping the first filtration device 2 with different filter versions, depending on a forecast degree of outside pollution linked to the location where the device itself is installed.

[0051] Optionally, the first filtration device 2 comprises two sensors 22 for detecting the particulate concentration in the outdoor air, housed respectively upstream and downstream of the first filtration unit 25, in order to monitor the correct functioning of the first filtration unit 25.

[0052] The first filtration device 2 can comprise an identification device for identifying the filter type, configured to identify the filter type ( for example, the model, the size or the diameter of the pores) of the first filtration unit 25 and to prevent the use of unsuitable filters .

[0053] Preferably, the first filtration device 2 comprises a monitoring device (not shown) for monitoring and managing maintenance of the filters of the first filtration unit 25. In particular, the monitoring device is configured to monitor a state of clogging of the filters and to send a warning signal to the processing and control unit 26 indicating the need for cleaning / replacement of the filters, thus avoiding undermining the aeraulic performance of the first filtration unit 25.

[0054] According to the embodiment shown in Figure 2, the first filtration device 2 further comprises a flow rate sensor 30 configured to detect the renewal air flow rate Prin and to send a signal correlated to it to the processing and control unit 26.In particular, the processing and control unit 26 is configured to determine an error given by a difference between the signal generated by the flow rate sensor 30 and the first control signal Cl, and also to control the first ventilator 24 based on the error through a control law, for example of the proportional or proportional-integral or proportional-integral-derivative type, in order to minimise the error .

[0055] Advantageously, the first filtration device 2 can comprise other sensors, such as, for example, a relative humidity sensor, a temperature and / or pressure sensor of the renewal air flow rate Pnn.

[0056] Preferably, the first filtration device 2 comprises a pressure sensor 60 arranged downstream of the first filtration unit 25, which is configured to generate a third input signal S3 for the processing and control unit 26, wherein the processing and control unit 26 is configured to generate the first control signal Cl in response to the third input signal S3.

[0057] In Figure 2, a combined relative humidity and temperature sensor 33 is shown by way of example, arranged upstream of the first filtration unit 25.

[0058] As shown in Figure 3, the second filtration device 19 comprises a second filtration unit 34 and a second ventilator 35 arranged in series with one another .

[0059] Preferably, the second filtration unit 34 comprises at least one sanitisation filter 36, for example an activated charcoal filter, an ionisation filter, a non-thermal plasma (NTP) filter, a UV filter or similar, capable of removing volatile organic compounds, germs, viruses or bacteria from the air or capable of activating the air as a sanitising carrier for the environment 11 .Advantageously, use of the sanitising filter avoids the possibility of any pathogens that have formed in the recirculation duct 18 or in the intake duct 12, due to the humidity level or in circulation in the indoor environment 11, being recirculated therein, thus sanitising the air in the indoor environment 11.

[0060] Optionally, the second filtration device 19 further comprises two detection sensors 37 for detecting the concentration of volatile organic compounds, housed respectively upstream and downstream of the second filtration unit 34, so as to detect such concentration upstream and downstream of the second filtration unit 34 and transmit it to the processing and control unit 26 in order to monitor the correct functioning of the second filtration unit 34.

[0061] Optionally, the second sensor 23 is also housed inside the second filtration device 19.

[0062] The processing and control unit 26 generates a second control signal 02 for the second ventilator 35 based on the first input signal SI and the second input signal S2 .

[0063] In particular, the second control signal 02 is correlated with a reference value of a recirculation air flow rate Pric drawn in by the second ventilator 35 and therefore taken from the intake duct 12 and introduced into the first node 8 after having been filtered by the second filtration unit 34.

[0064] Therefore, a supply air flow rate Pimm equal to the sum of the renewal air flow rate Prin and the recirculation air flow rate Pric is supplied into the indoor environment 11, through the supply duct 9.

[0065] A first non-limiting example of the operating logic of the processing and control unit 26 is described below.The processing and control unit 26 calculates a reference value of the renewal air flow rate Prin and a reference value of the recirculation air flow rate Pric based on the particulate concentration detected by the first sensor 22 and based on the carbon dioxide concentration detected by the second sensor 23 or an equivalent carbon dioxide concentration determined on the basis of the concentration of VOC detected by the third sensor 7 .

[0066] In particular, the particulate or carbon dioxide concentration values are compared with a predefined threshold and / or a predefined range .

[0067] Table 1 shows a first operating logic that applies if the particulate concentration in the outdoor air is lower than a first threshold, for example 50pg / m3.

[0068] Table 1

[0069] Full Up to 700 Up to 1000 "Boost" capacity ppm ppm 30 min

[0070] CO2 (ppm) < 800 800-1200 1200-1500 > 1500

[0071] Prin (V / h) 0 . 3 0 . 5 0 . 7 0 . 9

[0072] Pric (V / h) 0 . 1 0.2 0 . 3 0 . 1

[0073]

[0074] P™ (V / h) 0 . 4 0 . 7 1 1

[0075] With reference to Table 1, if the concentration or equivalent concentration of carbon dioxide in the indoor environment 11 is lower than 800 ppm, the processing and control unit 26 generates a first control signal Cl corresponding with a reference value of the renewal air flow rate Prin equal to 0.3 volume / hour (V / h) and a second control signal C2 corresponding with a reference value of the recirculation air flow rate Pric equal to 0.1 V / h,in which V corresponds with the volume of the indoor environment 11 .

[0076] The supply air flow rate Pimm is therefore equal to 0.4 V / h.

[0077] In the example shown in Table 1, if the particulate concentration in the outdoor air is lower than 50 pg / m3and the concentration or equivalent concentration of carbon dioxide is comprised in the range 800-1200 ppm, the signals Cl and C2 correspond with reference values equal respectively to 0.5 V / h and 0.2 V / h, up until the second sensor 23 detects a carbon dioxide concentration in the indoor environment 11 equal to or lower than 700 ppm.

[0078] If the particulate concentration in the outdoor air is lower than 50 pg / m3and the concentration of carbon dioxide is comprised in the range 1200-1400 ppm, the signals Cl and C2 correspond with reference values equal respectively to 0.7 V / h and 0.3 V / h, up until the second sensor 23 detects a carbon dioxide concentration in the indoor environment 11 equal to or lower than 1000 ppm.

[0079] The last condition (shown in the last column in Table 1 ) occurs if the first sensor 22 detects a carbon dioxide concentration higher than 1500 ppm; in this case, the signals Cl and C2 correspond with reference values equal respectively to 0.5 V / h and 0.5 V / h, determining a constant value of the supply air flow rate Pimm equal to 1 V / h in a predefined period of time, for example thirty minutes .

[0080] Table 2 shows a second operating logic that is applied if the particulate concentration in the outdoor air is higher than the first threshold, in the present example 50pg / m3.

[0081] Table 2full

[0082] Up to 700 ppm Up to 1000 ppm capacity

[0083] CO2 (ppm) < 800 800-1200 > 1200

[0084] Prin (V / h) 0 . 1 0 . 3 0 . 5

[0085] Pric (V / h) 0 . 3 0 . 4 0 . 5

[0086] P™ (V / h)

[0087] 0 . 4 0 . 7 1

[0088]

[0089] With reference to Table 2, if the concentration of carbon dioxide in the indoor environment 11 is lower than 800 ppm, the processing and control unit 26 generates a first input signal Cl corresponding with a reference value of the renewal air flow rate Prin equal to 0.1 V / h and a second input signal C2 corresponding with a reference value of the recirculation air flow rate Pric equal to 0.3 V / h.

[0090] The supply air flow rate Pimm is therefore equal to 0.4 V / h.

[0091] In the example shown in Table 2, if the particulate concentration in the outdoor air is higher than 50 pg / m3and the concentration of carbon dioxide is comprised in the range 800-1200 ppm, the signals Cl and C2 correspond with reference values equal respectively to 0.3 V / h and 0.4 V / h, up until the second sensor 23 detects a carbon dioxide concentration in the indoor environment 11 equal to or lower than 700 ppm.

[0092] If the particulate concentration in the outdoor air is higher than 50 pg / m3and the concentration or equivalent concentration of carbon dioxide is higher than 1200 ppm, the signals Cl and C2 correspond with reference values equal respectively to 0.5 V / h and 0.5 V / h, up until the second sensor 23 detects a carbon dioxide concentration in the indoor environment 11 equal to or lower than 1000 ppm.A non-limiting example of a third operating logic of the processing and control unit 26 is described below.

[0093] In particular, the third sensor 37 transmits the concentration detected to the processing and control unit 26, which calculates a reference value of the recirculation air flow rate Pric based on the particulate concentration detected by the first sensor 22, the carbon dioxide concentration detected by the second sensor 23 and based on a fourth input signal S4 correlated with the concentration of volatile organic compounds detected by the third sensor 37.

[0094] In particular, the processing and control unit 26 calculates a first reference value of the recirculation air flow rate Pric according to one of the operating logics described above, depending on the particulate concentration in the outdoor air, and a second reference value of the recirculation air flow rate Pric based on the concentration of volatile organic compounds detected by the third sensor 37.

[0095] An example of calculation of the second reference value of the recirculation air flow rate Pric is shown in Table 3.

[0096] Table 3

[0097] full Up to 200 Up to 500 "Boost" 30 capacity pg / m3pg / m3min

[0098] voc

[0099] < 300 300-600 600-800 > 800

[0100] (pg / m3)

[0101]

[0102] Pric (V / h) 0 . 1 0.2 0 . 3 0 . 4

[0103] As shown in Table 3, if the concentration of volatile organic compounds is lower than 300 pg / m3, the second reference valueof the recirculation air flow rate Pric is equal to 0.1 V / h.

[0104] If the concentration of volatile organic compounds is comprised in the range 300-600 pg / m3, the second reference value of the recirculation air flow rate Pric is equal to 0 / : V / h and is maintained constant up until when the third sensor 37 detects a concentration equal to or lower than 200 pg / m3.

[0105] Similarly, if the concentration of volatile organic compounds is comprised in the range 600-800 pg / m3, the second reference value of the recirculation air flow rate Pric is equal to 0.3 V / h and is maintained constant up until when the third sensor 37 detects a concentration equal to or lower than 500 pg / m3.

[0106] In the last column, an example is shown wherein the concentration of volatile organic compounds is higher than 1000 pg / m3, wherein the second reference value of the recirculation air flow rate Pric is set at 0.4 V / h and is maintained constant for thirty minutes .

[0107] Instant by instant, the processing and control unit 26 compares the first reference value and the second reference value of the recirculation air flow rate Pric and generates the second control signal C2 corresponding with the higher between the first reference value and the second reference value .

[0108] Preferably, the processing and control unit 26 is connected to the first sensor 22, to the second sensor 23, to the third sensor 37, to the first ventilator 24 and to the second ventilator 35 through a wireless connection, for example via wi-fi, Bluetooth Low Energy (BLE) , or through a cabled connection, for example through an Ethernet cable or similar, or through serial communication protocols, for example a Modbus RTU protocol .

[0109] Figure 4 shows a ventilation system 40 according to a different embodiment of the invention, which is described below insofaras it differs from the system 1 of Figure 1, using the same reference numbers to indicate elements that are identical to or that correspond with the elements already described.

[0110] By way of example, the system 40 is dedicated to ventilation of an indoor environment 11 formed of an apartment comprising a living area, a sleeping area, a bathroom and a kitchen (not shown) .

[0111] The system 40 comprises a controlled mechanical ventilation unit (CMV) 41 having a first inlet 42 connected to the outlet duct 7 of the first filtration device 2 , a second inlet 43 connected to a first return manifold 44 communicating with a first suction port 45 from the kitchen and a second suction port 46 from the bathroom, a third inlet 47 connected to a second return manifold 48 and communicating with a plurality of intake air inlets 49 from the living area and from the sleeping area .

[0112] The CMV unit 41 further comprises a first outlet 50 connected to the inlet 20 of a second filtration device 19, an outlet 21 of which is connected by the supply duct 9 to a plurality of supply inlets 51.

[0113] The CMV unit 41 comprises a second outlet 52 connected to the expulsion outlet 17 by the expulsion duct 16.

[0114] The CMV unit 41 is configured so that the first inlet 42 and the third inlet 47 are connected with the first outlet 50 and the second inlet 43 is connected with the second outlet 52.

[0115] The CMV unit 41 comprises, in a known way and not shown, at least one ventilator and thermal exchange means between the air supplied and the air expelled.

[0116] The system 40 comprises a vent duct 53 interposed between a node 54 arranged along the first manifold 44 and a node 55 arrangedalong a second manifold 48 and capable of allowing the extraction of a vent air flow rate PSf from the second manifold 48 and the expulsion thereof through the CMV unit 41 and the expulsion duct 16.

[0117] Conveniently, in order to modulate the vent air flow rate PSf, the nodes 54, 55 are provided with respective regulating dampers (not shown) .

[0118] In this embodiment as well, the renewal and recirculation air flow rates are determined by a processing and control unit 26 forming part of the first filtration device 2.

[0119] The CMV unit 41 and the second filtration device 19 can be controlled by the processing and control unit 26 remotely, on the basis of the input signals SI correlated with the particulate concentration, S2 correlated with the carbon dioxide concentration and optionally a fourth input signal S4 correlated with the concentration of volatile organic compounds as described previously.

[0120] Preferably, the processing and control unit 26 controls the CMV unit 41 through a wireless connection, for example via wi-fi, Bluetooth Low Energy (BLE) , or through a cabled connection, for example through an Ethernet cable or similar, or through serial communication protocols, for example a Modbus RTU protocol .

[0121] The first filtration device 2 is also configured to operate "as a follower of" the flow rate of the CMV if the latter cannot be managed by an external signal .

[0122] In that case, the CMV can be controlled in hourly programs or manually by the user .

[0123] The processing and control unit 26 is configured to generate a control signal Cl for the first ventilator 24, so as to compensate for the pressure drop through the first filtrationunit 25 and to ensure that the CMV does not "see" additional incoming pressure drops .

[0124] This can be performed with two different logics .

[0125] In a first case, the first ventilator 24 can be controlled on the basis of the input signal S3 received from the pressure sensor 60 so as to maintain a fixed pressure level downstream of the first filtration unit 25.

[0126] In a second case, the pressure level can vary as a function of the flow rate detected through the flow rate sensor 30.

[0127] The advantages of the filtration device and the ventilation system according to the present invention are clear from the above .

[0128] In the first place, the system 1, 40 is capable of ensuring an optimal quality of the air in the indoor environment regardless of the quality of the outdoor air .

[0129] The filters 27, 28 and 29 can be chosen on the basis of the air quality in the place of application, which can be mapped on the basis of statistical data .

[0130] The system 1, 40 can therefore be adapted to applications in various contexts, such as workplaces or public places, private homes and hospitality structures . In particular, the filtration device 2 according to the present invention can be used as an independent unit or in combination with an existing CMV, as described, and / or with other devices, such as thermal air treatment devices, for example dehumidifying coils, or compressor refrigeration circuits, heat exchangers for thermal recovery of the expelled air, pre-treatment and post-treatment units, both hydronic and electric . In detail, the filtration device 2 can be integrated into any ventilation system, withoutstructural or functional constraints with respect to the specific ventilation system.

[0131] In conclusion, it is clear that changes and variants can be made to the filtration device and ventilation system according to the present invention without thus deviating from the scope of protection as defined by the claims .

[0132] For example, the first filtration device 2 and / or the second filtration device 19 can be an integral part of the CMV unit 41 .

[0133] The first filtration device 2 and the second filtration device 19 can be integrated with each other to form a single filtration unit .

[0134] Furthermore, the system can be provided with controlled dampers to optimise the performance thereof .

Claims

CLAIMS1 . Filtration device ( 2 ) for a ventilation system ( 1 , 40 ) of at least one indoor environment ( 11 ) , the ventilation system ( 1 , 40 ) being capable of introducing into the indoor environment ( 11 ) a supply air flow rate ( Pimm) comprising a recirculation air flow rate ( Pric) from the indoor environment ( 11 ) and a renewal air flow rate ( Prin) from the outdoor environment ; the filtration device ( 2 ) comprising :• first ventilation means ( 24 ) configured to draw in the renewal air flow rate ( Prin) and feed it into the ventilation system ( 1 , 40 ) ;• first filtration means ( 25 ) configured to filter the renewal air flow rate ( Prin ) ;• processing and control means ( 26 ) configured to :- receive at least a first input signal ( S I ) from first detection means ( 22 ) for detecting at least a first parameter correlated with outdoor air quality;- receive at least a second input signal ( S2 ) from second detection means ( 23 ) for detecting at least a second parameter correlated with the air quality in the indoor environment ( 11 ) ; and- generating, on the basis of the first input signal ( S I ) and the second input signal ( S2 ) , a first control s ignal ( Cl ) for the first ventilation means ( 24 ) and a second control signal ( C2 ) for second ventilation means ( 35 ) of the ventilation system ( 1 , 40 ) , said second ventilation means ( 35 ) being capable of generating the recirculation flow rate ( Pric) or the supply air flow rate ( Pimm) ;said first and second control signals ( Cl , C2 ) being correlated with respective reference values of the renewal air flow rate ( Prin ) and the recirculation air flow rate ( Pric ) or the supply air flow rate ( Pimm) .2 . Filtration device as claimed in claim 1 , wherein the first parameter is a concentration of particulate matter in theoutdoor air .

3. Filtration device as claimed in claim 1 or 2, wherein the second parameter is a concentration of carbon dioxide in the air of the indoor environment ( 11 ) or an equivalent carbon dioxide concentration determined on the basis of a concentration of volatile organic compounds in the air of the indoor environment (11 ) •4. Filtration device as claimed in any one of the preceding claims, further comprising a flow sensor (30) configured to detect the renewal air flow rate (Prin) .

5. Filtration device as claimed in any one of the preceding claims, further comprising a pressure sensor ( 60) disposed downstream of the first filtration means (25) and configured to generate a third input signal (S3) for the processing and control means (26) , the processing and control means (26) being further configured to generate the first control signal (Cl ) in response to the third input signal (S3) .

6. Filtration device as claimed in any one of the preceding claims, wherein the first filtration means (25) comprises a plurality of filters (27, 28, 29) arranged in series .

7. Ventilation system ( 1, 40) comprising:• at least one external air intake (5) configured to allow renewal air flow rate (Prin) to enter the ventilation system (1, 40) ;• a first filtration device (2 ) as claimed in any one of claims 1-6, connected to the external air intake (5) and capable of being passed through by the renewal air flow rate (Prin) ;• at least one supply duct ( 9) for supplying the supply air flow rate (Pimm) into the indoor environment ( 11 ) , the supply duct ( 9) being connected at least indirectly to the first filtration device (2 ) so as to receive from the first filtrationdevice (2 ) the renewal air flow rate (Prin) ;• second ventilation means at least indirectly connected to at least one intake air inlet ( 14, 49) from the indoor environment ( 11 ) and connected to the supply duct ( 9) to generate the recirculation air flow rate (Pric) or the supply air flow rate (Pimm) ; and• said first and second detection means (22, 23) .

8. Ventilation system as claimed in claim 7, wherein said first detection means (22 ) comprise at least one sensor of particulate concentration in the outdoor air .

9. Ventilation system as claimed in claim 7 or 8, wherein said second detection means (23) comprise at least one sensor of carbon dioxide concentration in the air of the indoor environment ( 11 ) or an equivalent carbon dioxide concentration determined on the basis of a concentration of volatile organic compounds in the air of the indoor environment ( 11 ) .

10. Ventilation system as claimed in any one of claims 7-9, comprising a second filtration device ( 19) having an inlet (20) connected at least indirectly to the intake air inlet ( 14, 49) and an outlet (21 ) connected to the supply duct ( 9) .

11. Ventilation system as claimed in claim 10, wherein the second filtration device ( 19) comprises :• the second ventilation means (35) ; and• second filtration means (36) arranged in series with the second ventilation means (35) and configured to filter at least one of the renewal air flow rate (Prin) and the recirculation air flow rate (Pric) .

12. Ventilation system as claimed in any one of claims 7 to 11, wherein the ventilation system ( 1, 40) comprises third detection means (37 ) for detecting a concentration of volatile organic compounds in the air of the indoor environment ( 11 ) ,wherein the second control signal (C2 ) is generated on the basis of the first input signal (SI ) , the second input signal (S2 ) and a fourth input signal (S4 ) correlated to the concentration of volatile organic compounds in the air of the indoor environment (11 ) •13. Ventilation system as claimed in any one of claims 10 to 12, comprising a mechanical ventilation unit (41 ) controlled by the processing and control means (26) for providing at least one of the renewal air flow rate (Prin) and the recirculation air flow rate (Pric) to the second filtration device ( 19) .

14. Ventilation system as claimed in claim 13, wherein at least one of the first filtration device (2 ) and the second filtration device ( 19) is integrated in the mechanical ventilation unit (41 ) .

15. Ventilation system as claimed in any one of claims 10 to 14, wherein the first filtration device (2 ) and the second filtration device ( 19) are integrated in a single filtration unit .

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