WO2016000889A1

WO2016000889A1 - System for catalytically treating the air of a room of a building

Info

Publication number: WO2016000889A1
Application number: PCT/EP2015/062165
Authority: WO
Inventors: Franck Alessi
Original assignee: Commissariat A L'energie Atomique Et Aux Energies Alternatives
Priority date: 2014-06-30
Filing date: 2015-06-01
Publication date: 2016-01-07
Also published as: FR3022786A1; FR3022786B1; EP3160621A1

Abstract

The room comprises a wall shell (1). The system comprises an additional wall (2), a support structure (3) intended to be disposed in an inner housing (6) delimited by the two walls (1, 2), a photocatalytic substrate (4) and a lighting device (5) intended to activate the photocatalytic substrate. The two walls (1, 2), called the outer wall and inner wall respectively, each comprise at least one air vent, called an outer air vent (10H, 10B) and an inner air vent (20H, 20B) respectively. The support structure (3) comprises at least one valve portion (30H, 30B) designed to form air passageways between the inner air vent (20H, 20B), the outer air vent (10H, 10B) and the inner housing (6), provided with controllable sealing devices (35H, 35B, 36H, 36B). A control module controls the opening and the closing of the air passageways depending on measured data (C_int, C_ext) representative of the quality of the outside air and the quality of the inside air.

Description

Title: Photocatalytic Treatment of Air in a Room of a Building

The invention relates to a photocatalyst air treatment system. Photocatalysis is based on illumination by solar light or artificial UV illumination of a semiconductor material, for example titanium dioxide TiO ₂ , also called photocatalyst or photocatalytic substrate. Illumination has the effect of creating electron-hole pairs on the surface of the semiconductor, via wavelengths in the UV (Ultra-Violet) whose energy is greater than the gap between the valence band and the band of conduction of the semiconductor. Electrons are emitted at the conduction band while holes are formed in the valence band. This phenomenon forms free radicals that are likely to react with compounds present in the surrounding environment, for example air.

Photocatalysis finds a particularly interesting application in the field of treatment, or purification, of air, especially in an interior space for example a living room. Indeed, it makes it possible to degrade certain chemical pollutants present in the air and to transform them into non-polluting elementary molecules, in particular carbon dioxide C0 ₂ and water vapor H ₂ 0. The semiconductor generally used in this process case is TiO ₂ titanium dioxide. To ensure efficient treatment of the polluted air, the UV energy must be sufficient. However, in an interior space, the light is generally filtered through windows and is not permanent. It is therefore necessary to provide artificial UV emission sources to illuminate the photocatalytic substrate without risk related to direct exposure by the occupant.

EP1520615 discloses a photocatalyst air treatment apparatus for installation in a living room, comprising:

a wall comprising a front face and a rear face which delimit an inner housing, the front face providing a low opening for the entry of polluted air and a high opening for the outlet of purified air; one or more expanded steel grids on which a TiO ₂ titanium dioxide film is deposited;

a lighting device comprising UVA lamps intended to activate the Ti0 _{2 film} .

Grids and lamps are arranged in the inner housing of the wall. Thanks to this, the UV light contribution can be adapted to the needs of photocatalysis while preserving the occupants of the room of a direct contact with the photocatalytic substrate and the UV lamps.

The present invention proposes to further improve the invention.

To this end, the invention relates to a photocatalytic treatment system of the air of a part of a building having a wall wall, comprising an additional wall, a support structure intended to be arranged in an inner housing delimited by the two walls, a photocatalytic substrate and a lighting device for activating the photocatalytic substrate, characterized in that the two walls, respectively external and internal, each having at least one air outlet, respectively external and internal:

• the support structure comprises at least a valve portion adapted to form air passageways between the inner vent, the external vent and the inner housing, provided with controllable shutter devices; and

• the system includes a control module designed to control the opening and closing of the air passageways based on measured data representative of the quality of the outside air and the quality of the indoor air.

Controlling the opening and closing of the air passageways makes it possible to adapt the configuration of the system according to the pollution conditions (that is to say, the air quality) in the room and outside so as to optimize the regulation of the air quality inside the room. Depending on the air quality conditions outside and inside the room, the system can take outside air and then blow it indoors, directly or after photocatalytic purification, and / or take the indoor air, purify it and then reinject it inside (in this case we speak of "recycling"). In addition, the photocatalytic substrate can be activated at any time, without exposing the occupants of the room to light rays.

Finally, the system allows a pre-heating of the outside air taken, thanks to the heat released by the lighting device, which makes it possible to increase the temperature of the inner wall and thus to improve the thermal comfort by radiation. .

Advantageously, the valve portion is shaped to act as a spacer between the two walls.

With this, the two walls can be easily positioned relative to each other during assembly of the system.

The system advantageously comprises all or part of the following additional features:

the valve part comprises a first external opening intended to be arranged against the external air vent, a second internal opening intended to be arranged against the internal air vent and a third opening of communication with the inner housing, each of the three openings being equipped with a controllable shutter device;

the support structure comprises two valve parts respectively in the high position and in the low position of the support structure;

- The lighting device is positioned between the two valve parts and mounted on the support structure;

- The photocatalytic substrate is applied to at least one of the support elements of the group comprising the inner face of the additional wall, the inner face of the wall, a metal grid mounted on the support structure;

the valve part comprises particulate filters;

- air circulation fans are provided;

the control module is adapted to implement an algorithm for controlling concentrations of pollutants in the air, inside and outside the room comprising a plurality of comparison tests between elements of the group comprising a measured indoor concentration of pollutants, measured outside pollutant concentration and concentration threshold, and, depending on test results, selection of a system configuration from a set of possible configurations;

the support structure comprising two valve portions, respectively low and high, each having an outer opening, an inner opening and a third opening, the set of possible configurations comprises all or part of the configurations of the group comprising:

o a first configuration defined by the closure of the three lower openings and the third upper opening and the opening of the upper openings, outer and inner;

o a second configuration defined by closing the outer openings and opening the inner openings and the third openings;

a third configuration defined by the opening of the upper inner opening, the lower outer opening and the third openings and the closing of the upper outer opening and the lower inner opening;

a fourth configuration defined by closing the upper outer opening and opening the inner openings, the third openings and the lower outer opening;

a fifth configuration defined by closing the lower outer opening and opening the inner openings, the third openings and the upper outer opening;

o a sixth configuration defined by the closing of the outer and inner openings;

there is provided an additional wall fixing device adapted to mount said additional wall on the wall wall pivotally. The invention will be better understood from the following description of a particular embodiment of the system with reference to the accompanying drawings in which:

- Figure 1 shows a view of the system of the invention mounted on a wall;

FIG. 2 represents a view of a support structure of the system of FIG. 1;

- Figures 3A and 3B show the system of Figure 1 before and after mounting on the wall, in top view;

FIG. 4 represents an exploded side view of the system of FIG.

1;

FIGS. 5A to 5H schematically represent different possible configurations of the system of FIG. 1;

FIG. 6 represents another embodiment of the system of the invention;

FIG. 7 represents a flow chart, or flowchart, of a control algorithm implemented by the system of FIG. 1, according to a particular embodiment example.

The air treatment system shown in Figures 1 and 2 is intended to treat the air of an interior space located in a building, for example a living room, by photocatalysis. In the particular example described here, the interior space is delimited by at least one wall wall 1 in direct contact, with an outer face, with the outside of the building.

The treatment system comprises an additional wall 2, a support structure, or carrier structure 3, a photocatalytic substrate 4, a lighting device 5 intended to activate the photocatalytic substrate 4, a control module (or device) (not shown) , pollutant sensors (not shown) and a module (or device) supply (not shown). Air circulation fans 7 can also equip the system. The additional wall:

The additional wall 2 is intended to be positioned at a given distance from the wall wall 1, here on the inside of the room, the space between the two walls 1, 2 defining an inner housing 6. The additional wall 2 and the wall wall 1 are here called "inner wall" and "outer wall", respectively. Alternatively, the additional wall could be disposed on the other side of the wall wall, outside the living room. In this case, the additional wall would be the outer wall and the wall wall the inner wall.

Each of the two walls, outer 1 and inner 2, here comprises a high air vent 10H, 20H and a low air vent 10B, 20B, as shown in Figure 3. Each vent has a passage opening of air through the wall considered. The high air vents 10H, 20H are positioned at the top of the walls and so arranged to the right of each other when the system is put in place. Similarly, the low air vents are positioned in the bottom of the walls so as to be arranged in line with each other when the system is put in place.

The support structure:

The support structure 3, or support structure, is intended to serve as a mounting support for various elements of the system. It also acts as a spacer between the inner wall 2 and the outer wall 1. The structure 3 is made of a robust material such as a metal or wood. In addition, the structure 3 can be made of a material inert with respect to the release of pollutants, for example stainless steel or anodized aluminum.

The supporting structure 3 comprises two parts, respectively high 30H and low 30B, intended to act as air circulation valves. Each 30H valve portion (30B) constitutes a three-way valve, adapted to form air passageways between the internal vent 20H (20B), the external vent 10H (10B) and the housing 6. Each passageway is provided with a controllable shutter device. More specifically, each 30H valve part (30B) is here in the form of a beam parallelepipedic having a first outer opening, a second inner opening and a third opening communicating with the housing 6. The three openings (first, second and third) high, respectively low, communicate with each other by forming an opening 34H, respectively 34B, having a T shape in cross section of the beam.

Each of the three high openings (first, second and third), respectively low, is associated with a shutter device which comprises a shutter element, a motor and a communication module. The motor is intended to move the shutter element between an open position and a closed position. The communication module is intended to communicate, for example by radio, with the control device in order to receive commands for opening, closing and / or stopping the shutter element. Alternatively, the communication module could be connected to the control device by a wire link.

The first and second openings, respectively inner and outer, are each equipped with a 35H (high grilles) and 35B (low grids) shutter grid with controllable blades movable between a closed position and an open position. These grids are here mounted on the vents 20H, 30H (20B, 30B) corresponding to the inner walls 2 and outer 1. Alternatively, they could be mounted on the support structure 3 itself. The third high opening (respectively low) is equipped with a 36H waterproof valve (respectively 36B) which is mounted on the support structure 3.

The closure grids 35H, 35B may be coupled with particulate filters for filtering particles present in the air. These filters are arranged near the closing grids so as to be adjacent to the air inlets and outlets of the treatment system. They make it possible to limit the internal fouling of the system, in particular by the dust, which reduces the maintenance operations and preserves the performances of the system.

The two valve parts 30H and 30B are connected by several vertical uprights, for example two lateral end posts 31 and two intermediate uprights 32. To solidify the structure, horizontal crosspieces of maintaining 33 here connect each intermediate amount 32 to the end amount 31 nearest.

The valve parts 30H and 30B have a width in the direction perpendicular to the planes of the walls 1 and 2 which is equal to the desired distance between the two walls 1, 2. This allows them to play their role of spacers. In order to lighten the structure and reduce manufacturing costs, the width of the uprights is advantageously less than that of the valve parts 30H and 30B.

The photocatalytic substrate:

The photocatalytic substrate is a semiconductor material capable of mineralizing pollutants present in the air by transforming them into carbon dioxide and water vapor, when subjected to illumination by radiations, here UV, which create electron-hole pairs on the surface of the semiconductor. Pollutants particularly targeted by photocatalysis are VOCs (Volatile Organic Compounds). The substrate used is, for example, TiO ₂ titanium dioxide. It can be applied in the form of a film, made from a coating, on a support element. The substrate may for example be deposited on one or more of the following support elements: the inner face (that is to say the "inner" face of the housing 6) of the outer wall 1, the inner face of the wall 2, a particulate filter, one or more uprights and / or cross members of the structure, the floor of the housing 6, the ceiling of the housing 6, a specific support element (for example an expanded metal grid). In the case of a specific support element, it is advantageously positioned and fixed parallel to the lighting device to maximize the illumination of the latter.

The photocatalytic substrate may be a substrate that can be activated by light rays of the visible spectrum. This is particularly the case with a photocatalytic substrate such as titanium dioxide doped for example with carbon, the doping enabling the substrate to be activated by light rays of the visible spectrum. The lighting device:

The lighting device 5 is intended to activate the photocatalytic substrate. In the embodiment described here, the lighting device 5 comprises a plurality of UV lamps 50, each lamp comprising for example one or more neon tubes mounted on a support frame. Each lamp 50 is fixed to the uprights and / or to the crosspieces of the support structure 3 by means of a support frame 51. In the embodiment shown in Figures 1 and 2, the system comprises six lamps each having two neon tubes.

Alternatively, the lighting device could include other types of artificial light sources or optical fibers adapted to carry light from a remote light source into the housing 6, for example to carry natural sunlight from outside the building. The fans:

Fans 7 may be installed to promote the flow of air along one or more desired circulation circuits, as will be explained in more detail in the description of the operation of the system. The flow of air flow that can be created or reinforced by the fans 7 may include in particular the suction of air from the room and / or from the outside, the scanning or licking of the photocatalytic substrate by the air to be treated, the blowing of treated air into the room and / or the direct ejection of outside air. During its installation, the additional wall 2 can be pivotally mounted on the wall wall 1, by means of a hinge device. Thanks to this, the system can be opened, by pivoting the additional wall, which allows easy maintenance of the system. The support structure 3 is here fixed to the wall wall 1 at the level of the beams of the valve parts 30H and 30B. The sensors:

The system comprises at least one external sensor and an inner sensor (not shown), intended here to measure the pollutant concentrations, respectively external (that is to say outside the room and here of the building) and inside (ie in the room). The pollutants detected here include total volatile organic compounds (TVOCs). The sensors each comprise a communication module (for example radio) for transmitting measured data representative of the quality of the air, either upon receipt of a request from the control device, or automatically at regular time intervals.

Other additional measures can be envisaged to detect specific pollutants and / or to carry out thermodynamic measurements (T °, humidity, C0 ₂ ) in order to obtain measured data representative of the air quality.

The device (or module) supply:

The lighting lamps, the motors of the shutter devices and the control device are connected to a supply device, for example connected to the mains.

The pilot device (or module):

The control device is intended to control the opening and closing of the air passageways based on measured data representative of the quality of the outside air and the quality of the indoor air. More specifically, it is intended to control the closing and opening of the closure devices apertures.

In the particular embodiment described here, the measured data representative of the quality of the air comprise measurements of concentration of pollutants in the air. However, the present invention is not limited to measurements of concentrations of pollutants in the air. In fact, the quality of the outside and / or inside air can be evaluated from other types of measured data such as temperature, hygrometry and / or content data. in CO2 in the air. The measured data representative of the air quality can therefore comprise, alternatively or complementary to the measurements of pollutant concentrations, other relevant measurements such as measurements of temperature, hygrometry and / or CO 2 content. air (outside and / or inside).

The control device comprises a microprocessor, a communication module and a software module, or computer program, comprising software instructions for controlling the execution by the microprocessor of an algorithm for regulating the concentrations of pollutants in the air. inside and outside the room when the software module is running. It can be arranged for example in the room.

The radio communication module is adapted to communicate in a conventional manner, for example by radio, with the pollutant sensors and with the motors of the shutter devices of the different openings, in order to transmit open / close / stop commands, data queries and receive measured data.

The control algorithm implemented by the control device is illustrated by the logic diagram shown in FIG. 7. This ultimately corresponds to a flowchart of the steps of the operating method of the system. This algorithm comprises multiple comparison tests between the measured indoor pollutant concentration Cim, the measured external pollutant concentration C _ext and / or an S concentration threshold. Depending on the result of these tests, the algorithm determines the pollution conditions. , or air quality, inside the room and outside, then, depending on these conditions, selects a configuration of the valve portions 30H, 30B of the system from a set of possible configurations of the system.

For the implementation of the algorithm, a subset of possible configurations of the system can be pre-selected from all possible configurations. This subset here comprises the following six configurations (the "openings" referred to hereinafter being those of the support structure): A first configuration CONF1 defined by the closing of the three lower openings and the third upper opening and by the opening of the upper openings (outer and inner);

• a second configuration CONF2 defined by the closing of the external openings and the opening of the internal openings

(high and low) and third openings (high and low);

A third configuration CONF3 defined by the opening of the upper inner opening, the lower outer opening and the third openings (high and low) and the closing of the upper outer opening and the lower inner opening;

A fourth configuration CONF4 defined by the closing of the upper outer opening and the opening of the inner openings (high and low), the third openings (high and low) and the low outer opening;

· A fifth configuration CONF5 defined by the closing of the lower outer opening and the opening of the inner openings (high and low), the third openings (high and low) and the upper outer opening;

A sixth configuration CONF6 defined by the closing of the outer and inner openings (high and low), the third openings (high and low) being open or closed (preferably closed to ensure sealing).

Of course, other configurations of the system could be used to provide indoor air recycling and / or direct or purified outside air supply (i.e., after photocatalyst purification in the system).

We will now describe, with reference to Figure 7, the operating method of the system, corresponding to the implementation of the control algorithm.

In the particular embodiment described here, the process is carried out during a cold season, for example between October and March in a region of the northern hemisphere, and the following conditions are met:

Ta _e xt <aint HA _ex t <HAint

or :

the parameter Ta represents the temperature of the air,

the parameter HA represents the absolute humidity of the air,

the index "ext" corresponds to the outside,

- the index "int" corresponds to the interior.

The method comprises a first step E0 measuring data representative of the quality of the air inside the living room and outside thereof. In the particular example described here, the internal concentration Cint is measured as pollutants and the external concentration C _ext as pollutants. As previously indicated, other measures could be carried out, alternatively or in addition, in order to obtain measurement data representative of the quality of indoor air and outdoor air.

This measurement step EO is followed by a plurality of comparison test steps between the data measured inside, the measured data outside and / or a predefined threshold. In this case, the test compares the measured internal concentration Cim, the measured outside concentration C _ext and / or a concentration threshold S. These comparative tests make it possible to distinguish different situations, or situations. Each case is defined by the conditions here _in the inner C concentrations and outdoor t C _ext. In the embodiment described here, the tests make it possible to identify six possible scenarios (or situations), denoted C1 to C6, which will be explained in the description that follows.

From the outset, it will be noted that the abbreviations "Y" and "N" on the flowchart of FIG. 7 represent a positive test result and a negative test result, respectively.

The threshold S used here may be an indoor air guide value (VGAI) in TVOC, a regulatory value, a normative value or a value chosen by an operator.

The measurement step EO is followed by a first comparison test step E1 of the measured indoor pollutant concentration C _in t and the measured external pollutant concentration C _ext . If the internal concentration Cint is strictly greater than the external concentration C _ext (positive test E1), the method goes to the test step E2 for comparing the internal concentration and the threshold S.

If the internal concentration Cint is less than or equal to the threshold S (negative test E2), it is determined that the conditions of external and internal concentrations correspond to the case of figure C1 for which we have:

S> Cint> Cext,

in other words, the internal concentration C _im is less than or equal to the threshold S and strictly greater than the external concentration C _ext .

In this case, the control module selects a configuration of the system allowing an outside air supply, for example the configuration CONF1, during a step E3. During a step E4, the control module controls the closing of the three low openings and the third high opening and the opening of the two upper outer and inner openings and the starting of the fans, so that The outside air is taken from the system through the top outer openings and then directly blown into the living room through the high interior openings without treatment.

If, during the test step E2, it is detected that the internal concentration is strictly greater than the threshold S (positive test E2), then the process goes to the test step E5 during which the external concentration C _ex t is compared to the threshold S.

If the external concentration is greater than or equal to the threshold S (positive test E5), the method determines that the conditions of external and internal concentrations correspond to the case of figure C2 for which we have:

in other words, the internal concentration C _im is strictly greater than the external concentration C _ex t which is itself greater than or equal to the threshold S.

In this case, the control module selects a configuration of the system allowing a supply of outside air treated with indoor air recycling, here CONF4 configuration, during a step E6. During a step E7, the control module controls the closing of the upper outer opening and the opening interior openings (high and low), third openings (high and low) and low outside opening and fan start-up. This configuration makes it possible to take the outside air through the low outside opening and the inside air through the lower inside opening. The outside air taken and the interior air removed are circulated inside the system so as to scan, that is to say to come lick, the photocatalytic substrate. At the same time, it is activated by illumination using UV lamps, which purifies the air taken by photocatalysis. The purified air, coming from outside and inside, is then ejected, or blown, into the living room, through the inner high opening.

If the external concentration is strictly lower than the threshold S (negative test E5), it is determined that the conditions of external and internal concentrations correspond to the case of figure C3 for which we have:

in other words, the internal concentration C _in t is strictly greater than the external concentration C _ext which is itself strictly greater than the threshold S.

In this case, the control module selects a configuration of the system allowing an intake of outside air with indoor air recycling here, in this case CONF5 configuration, during a step E8. During a step E9, the control module controls the closing of the low outer opening and the opening of the inner openings (high and low), the upper outer opening and the third openings (high and low) and the switching on the fans. Thus, indoor air is drawn through the system through the lower interior openings. This collected interior air is circulated in the system so as to lick the photocatalytic substrate, activated by UV illumination, before being ejected into the room through the high interior openings. In addition, outside air is drawn from the upper outside openings and blown into the living room through the high interior openings.

If the internal concentration Cint is strictly lower than the external concentration C _ext (negative test E1), the method goes to the comparison test step E10 of the external concentration with the threshold S. If the external concentration is greater than or equal to the threshold S (positive test E10), the process proceeds to a test step E1 1 for comparing the internal concentration C _in t with the threshold S.

If the concentration Cint is greater than or equal to the threshold S (test E1 1 positive), it is determined that the conditions of external and internal concentrations correspond to the case C4 figure for which we have:

in other words, the external concentration C _ex t is strictly greater than the internal concentration C _in t which itself is greater than or equal to the threshold S.

In this case, the control module selects a configuration of the system for recycling indoor air, in this case CONF2 configuration, during a step E12. During a step E13, the control module controls the closing of the external openings (high and low) and the opening of the inner openings (high and low) and the third openings (high and low), and the starting of the fans. Thus, indoor air is drawn through the system through the lower interior openings. This air is circulated inside the system so as to lick the photocatalytic substrate, activated by UV illumination, before being ejected into the room through the upper interior openings.

If the concentration C _im is strictly lower than the threshold S (test E1 1 negative), it is determined that the conditions of external and internal concentrations correspond to the case C5 for which we have:

Cext≥ S> Cint,

in other words, the internal concentration Cint is strictly below the threshold S and the external concentration C _ex t is greater than or equal to the threshold S.

In this case, the control module here selects a configuration of the system allowing a supply of outside air treated, in this case the configuration CONF3, during a step E14. During a step E15, the control module controls the opening of the upper inner opening, the lower outer opening and the third openings (high and low) and the closing of the upper outer opening and the second one. low interior opening, as well as turning on the fans. Thanks to this CONF3 configuration, outside air is picked up by the system through the lower outside openings. This air is circulated inside the system so as to lick the photocatalytic substrate, activated by UV illumination, before being ejected, or blown into the room, after purification, by the upper inner openings.

If the external concentration is strictly below the threshold S (test

E10 negative), it is determined that the conditions of external and internal concentrations correspond to the case C6 for which we have:

S> C _ex t> Cjnt,

in other words, the internal concentration Cint is strictly less than the external concentration C _ext which is itself strictly less than the threshold S.

In this case, the control module here selects a configuration of the system without outside air supply and without recirculation of indoor air, in this case CONF6 configuration, during a step E1 6. During a step E17 , the control module controls the closing of the outer and inner openings (high and low) and possibly the third openings (high and low). Thus, there is no outside air supply in the room and no recycling of the interior air of the room. This configuration can be used temporarily.

Finally, in the event of a tie between the external concentration C _ext and the internal concentration C _in t, it is possible to check whether these concentrations are greater than the threshold S. In the case of a positive test (that is to say C _ext > S and C _in t> S), one could for example apply a treatment comprising an indoor air recirculation, such as that of the CONF2 configuration. In the case of a negative test (ie C _e xt <S and Cim <S), normal ventilation, for example by implementing the CONF1 configuration, could be applied.

In the algorithm which has just been described, certain configurations of the system are selected according to the case (or cases) identified which are defined by a set of conditions relating to internal C concentrations _in t and outer C _ext. Other possible configurations of the system could be chosen alternatively to those which have just been described to respond to these same situations. The possible configurations include the configurations CONF1 to CONF6 already described. You can also add the following configurations, noted CONF7 and CONF8: CONF7 configuration:

This configuration CONF7 is defined by the opening of the upper openings (outer and inner), the lower outer opening and the third openings (high and low). The action of the fans is adapted so that outside air is collected by all the external openings (high and low) and then circulated in the system so as to scan the photocatalytic substrate under UV illumination and, after purification, ejected in the living room through the high interior openings.

- Configuration CONF8:

This configuration is defined by the opening of all the openings, that is to say the high openings, inner and outer, the lower openings, inner and outer, and third openings (high and low). The action of the fans is further adapted to collect outside air, through the upper and lower outer openings, and the inner air through the lower inner openings, to circulate the air taken from the system by licking the photocatalytic substrate and eject the purified air into the room through the high interior openings.

The table below illustrates, in a nonlimiting manner, different configurations that can be chosen according to the different cases, or situations, possible.

Table of configurations according to the cases:

CONF1 CONF2 CONF3 CONF4 CONF5 CONF6 CONF7 CONF8

C1 X X X

C2 X X X

C3 X X X X X X

C4 X X X

C5 X X

C6 XXX In the table above, the lines correspond to the different cases C1 to C6 and the columns represent the configurations CONF1 to CONF8. The checked boxes of a line represent the configurations of the system that can be chosen for the case corresponding to this line.

In the embodiment of the system as shown in Figures 1 and 2, each wall 1, 2 comprises two openings, respectively high and low. More generally, each wall may comprise one or more air passage openings, the different configurations of the system being adapted to the number and positions of the openings to ensure the various functions described: indoor air recycling ( that is to say, intake of internal air, purification and reinjection inwards) and / or supply of purified outside air and / or direct supply of outside air without purification and / or no contribution and no recycling. 'air.

In Figure 6, there is shown another embodiment of the system. In this embodiment, the system has a sheet structure to optimize the contact between the polluted air and the photocatalytic substrate. The housing 6 contains here between the inner faces of the walls 1 and 2, two structures carrying lighting devices between which a plate coated on both sides of photocatalytic substrate is interposed. It would of course be possible to multiply the number of plates coated with photocatalytic substrate and light-carrying structures that are alternately arranged inside the housing 6, depending on the purification requirements, the desired insulation and the level required. desired power consumption.

Claims

1. Photocatalytic treatment system for the air of a room of a building having a wall wall (1), comprising an additional wall (2), a support structure (3) intended to be arranged in an inner housing (6) delimited by the two walls (1, 2), a photocatalytic substrate (4) and a lighting device (5) for activating the photocatalytic substrate,

characterized in that the two walls (1, 2), respectively external and internal, each having at least one aeration mouth, respectively external (10H, 10B) and internal (20H, 20B):

The support structure (3) comprises at least one valve portion (30H, 30B) adapted to form air passageways between the internal air vent (20H, 20B), the external air vent (10H). 10B) and the inner housing (6) provided with controllable shutter devices (35H, 35B, 36H, 36B); and

• The system includes a control module designed to control the opening and closing of air passageways based on measured data (Cim, C _ext ) representative of the quality of the outside air and the quality of the air. indoor air.

2. System according to the preceding claim, characterized in that the valve portion (30H, 30B) is shaped to act as a spacer between the two walls (1, 2).

3. System according to one of the preceding claims, characterized in that the valve portion (30H, 30B) comprises a first outer opening (34H, 34B) intended to be arranged against the external vent (10H, 10B), a second inner opening (34H, 34B) to be disposed against the inner vent (20H, 20B) and a third opening (34H, 34B) communicating with the inner housing (6), each of the three openings being equipped with a controllable shutter device (35H, 35B, 36H, 36B).

System according to one of the preceding claims, characterized in that the support structure (3) comprises two valve parts (30H, 30B) respectively in the high position and in the low position of the support structure.

System according to the preceding claim, characterized in that the lighting device (5) is positioned between the two valve parts (30H, 30B) and mounted on the support structure (3).

System according to one of the preceding claims, characterized in that the photocatalytic substrate (4) is applied to at least one of the support elements of the group comprising the internal face of the additional wall, the internal face of the wall wall,, a metal grid mounted on the support structure.

System according to one of the preceding claims, characterized in that the valve part (30H, 30B) comprises particulate filters.

System according to one of the preceding claims, characterized in that it comprises fans (7) of air circulation.

System according to one of the preceding claims, characterized in that the control module is adapted to implement an algorithm (E0-E1 7) for regulating pollutant concentrations in the air, inside and at the outside the room comprising a plurality of comparison tests between elements of the group comprising a measured indoor pollutant concentration (C _in t), a measured external pollutant concentration (C _ext ) and a concentration threshold (S), and, depending on the test results, selecting a configuration of the system among a set of possible configurations (CONF1 - CONF6).

10. System according to claim 9, characterized in that the support structure (3) comprising two valve portions, respectively low (30B) and high (30H), each having an outer opening, an inner opening and a third opening, the set of possible configurations comprises all or part of the configurations of the group comprising:

A first configuration (CONF1) defined by the closing of the three lower openings and the third upper opening and the opening of the upper, outer and inner openings;

• a second configuration (CONF2) defined by the closing of the outer openings and the opening of the inner openings and the third openings;

A third configuration (CONF3) defined by the opening of the upper inner opening, the lower outer opening and the third openings and closing the upper outer opening and the lower inner opening;

A fourth configuration (CONF4) defined by closing the upper outer opening and opening the inner openings, the third openings and the lower outer opening;

A fifth configuration (CONF5) defined by the closing of the low outer opening and the opening of the inner openings, the third openings and the upper outer opening;

• a sixth configuration (CONF6) defined by the closing of the outer and inner openings.

1 1. System according to claim 10, characterized in that it comprises a device for fixing the additional wall (2) adapted to mount said additional wall on the wall wall pivotally.