FIELD OF THE INVENTION

The invention relates to a gas treatment system. The invention also relates to an air control system comprising such gas treatment system. Further, the invention relates to a method for treating air.

BACKGROUND OF THE INVENTION

Air supply apparatuses are known in the art. US2009004047, for instance, describes an air sterilizer, comprising a UV light source for providing UV radiation of a first intensity, a blower for generating an air stream, a particle filter for filtering particles out of the air stream, and means for radiating pathogens in the air stream with high intensity UV light in a high intensity zone, wherein the high intensity light is of a higher intensity than the first intensity. The high intensity zone includes a reflector for reflecting back UV light.

SUMMARY OF THE INVENTION

UV light has been used for disinfection for over 100 years. Wavelengths between about 190 nm and 300 nm may be strongly absorbed by nucleic acids, which may result in defects in an organism’s genome. This may be desired for inactivating (killing), bacteria and viruses, but may also have undesired side effects for humans. Therefore the selection of wavelength of radiation, intensity of radiation and duration of irradiation may be limited in environments where people may reside such as offices, public transport, cinema’s, restaurants, shops, etc., thus limiting the disinfection capacity. Especially in such environments, additional measures of disinfection may be advantageous to prevent the spread of bacteria and viruses such as influenza or novel (corona) viruses like COVID-19, SARS and MERS.

It appears desirable to produce systems, that provide alternative ways for air treatment, such as disinfection. Further, existing systems for disinfection may not easily be implemented in existing infrastructure, such as in existing buildings like offices, hospitality areas, etc. and/or may not easily be able to serve larger spaces. This may again increase the risk of contamination. Further, incorporation in HVAC systems may not lead to desirable effects and appears to be relatively complex. Further, existing systems may not be efficient, or may be relatively bulky, and may also not easily be incorporated in functional devices, such as e.g. luminaires.

Other disinfection systems may use one or more anti -microbial and/or anti- viral means to disinfect a space or an object. Examples of such means may be chemical agents which may raise concerns. For instance, the chemical agents may also be harmful for people and pets.

In embodiments, the disinfecting light, may especially comprise ultraviolet (UV) radiation (and/or optionally violet radiation), i.e., the light may comprise a wavelength selected from the ultraviolet wavelength range (and/or optionally the violet wavelength range). However, other wavelengths are herein not excluded. The ultraviolet wavelength range is defined as light in a wavelength range from 100 to 380 nm and can be divided into different types of UV light / UV wavelength ranges (Table 1). Different UV wavelengths of radiation may have different properties and thus may have different compatibility with human presence and may have different effects when used for disinfection (Table 1).

Table 1: Properties of different types of UV (and violet) wavelength light

Each UV type / wavelength range may have different benefits and/or drawbacks. Relevant aspects may be (relative) sterilization effectiveness, safety (regarding radiation), and ozone production (as result of its radiation). Depending on an application a specific type of UV light or a specific combination of UV light types may be selected and provides superior performance over other types of UV light. UV-A may be (relatively) safe and may inactivate (kill) bacteria, but may be less effective in inactivating (killing) viruses. UV-B may be (relatively) safe when a low dose (i.e. low exposure time and/or low intensity) is used, may inactivate (kill) bacteria, and may be moderately effective in inactivating (killing) viruses. UV-B may also have the additional benefit that it can be used effectively in the production of vitamin D in a skin of a person or animal. Near UV-C may be relatively unsafe, but may effectively inactivating, especially kill bacteria and viruses. Far UV-C (or far UV) may also be effective in inactivating (killing) bacteria and viruses, but may be (relatively to other UV-C wavelength ranges) (rather) safe. Far-UV light may generate some ozone which may be harmful for human beings and animals. Extreme UV-C may also be effective in inactivating (killing) bacteria and viruses, but may be relatively unsafe. Extreme UV-C may generate ozone which may be undesired when exposed to human beings or animals. In some application ozone may be desired and may contribute to disinfection, but then its shielding from humans and animals may be desired. Hence, in the table “+” for ozone production especially implies that ozone is produced which may be useful for disinfection applications, but may be harmful for humans / animals when they are exposed to it. Hence, in many applications this “+” may actually be undesired while in others, it may be desired. The types of light indicated in above table may in embodiments be used to sanitize air and/or surfaces.

The terms “inactivating” and “killing” with respect to a virus may herein especially refer to damaging the virus in such a way that the virus can no longer infect and/or reproduce in a host cell, i.e., the virus may be (essentially) harmless after inactivation or killing.

Hence, in embodiments, the light may comprise a wavelength in the UV-A range. In further embodiments, the light may comprise a wavelength in the UV-B range. In further embodiments, the light may comprise a wavelength in the Near UV-C range. In further embodiments, the light may comprise a wavelength in the Far UV-C range. In further embodiments, the light may comprise a wavelength in the extreme UV-C range. The Near UV-C, the Far UV-C and the extreme UV-C ranges may herein also collectively be referred to as the UV-C range. Hence, in embodiments, the light may comprise a wavelength in the UV-C range. In other embodiments, the light may comprise violet radiation.

It appears desirable to provide a system which may treat air. Such system may e.g. treat air with one of the above-mentioned types of radiation, especially UV radiation (A, B, or C). However, it is desirable that the fluence rate provided is provided in such a way that all air is treated, and that there are essentially no dead spaces which would allow air to leave the air treatment system without being treated.

Hence, it is an aspect of the invention to provide an alternative system which preferably further at least partly obviates one or more of above-described drawbacks. The present invention may have as object to overcome or ameliorate at least one of the disadvantages of the prior art, or to provide a useful alternative. Especially, it is desired to provide a gas treatment (or disinfection) system having an improved safety and/or disinfection performance.

Therefore, in a first aspect the invention provides a gas treatment system comprising a radiation unit and a hollow reflector. Especially, the radiation unit is configured to generate (during operation of the radiation unit) radiation having one or more wavelengths, selected from the range of 100-420 nm, in specific embodiments selected from the wavelength range of 100-380 nm. Further, especially the hollow reflector may be configured to receive at least part of the radiation of the radiation unit. In embodiments, the hollow reflector comprises (i) a first opening, (ii) a second opening. Further, the hollow reflector may comprise (iii) a wall at least partly bridging a length (L) between the first opening and the second opening. The wall may especially define a gas flow channel between the first opening and the second opening. Further, especially at least part of the wall has a reflective surface. Especially, the reflective surface is reflective for the radiation (of the radiation unit). Further, in embodiments the hollow reflector comprises an end part, especially in embodiments two end parts, (each) comprising a part of the reflective surface. In embodiments, the end part comprises one of the first opening and the second opening, or comprises both the first opening and the second opening. In other embodiments, the hollow reflector may comprise two end parts, with in specific embodiments (each) comprising a part of the reflective surface. Especially, in embodiments one of the end parts may comprise the first opening and the other one of the end parts may comprise the second opening. Especially, in embodiments the reflective surface of the end part(s) is (a) facetted in a length direction of the hollow reflector, and (b) (optionally) tapered in a direction of the respective opening. Hence, especially the invention provides in embodiments a gas treatment system comprising a radiation unit and a hollow reflector, wherein: (A) the radiation unit is configured to generate radiation having one or more wavelengths selected from the wavelength range of 100-380 nm; (B) the hollow reflector is configured to receive at least part of the radiation of the radiation unit; wherein the hollow reflector comprises (i) a first opening, (ii) a second opening, and (iii) a wall at least partly bridging a length (L) between the first opening and the second opening and defining a gas flow channel between the first opening and the second opening; wherein at least part of the wall has a reflective surface, reflective for the radiation; and (C) the hollow reflector comprises two end parts each comprising a part of the reflective surface, with one of the end parts comprising the first opening and the other one of the end parts comprising the second opening; wherein the reflective surface of the end parts is (a) facetted in a length direction of the hollow reflector, and (b) tapered in directions of the respective openings.

With such gas treatment system air may be treated efficiently within the hollow reflector. It appears that a substantial part of the radiation stays trapped in the hollow reflector. Further, it appears that the fluence rate may be relatively homogenous over the cross-section of the hollow reflector. This allows an effective treatment and may also prevent the occurrence of dead spaces which may lead to untreated air. Therefore, the hollow reflector may e.g. be used as disinfection chamber. Hence, a substantially perfect uniform fluence rate and a high UV utilization may be achieved with the present gas treatment system. Substantially no radiation may escape via the openings in the disinfection chamber to the outside. This may create an optimal use of UV radiation and may protect the user from UV light leaking out of the cavity. Further, this may allow to use a lower UV intensity and/or to use less UV protection measures. Yet further, this may also allow higher gas flows.

As indicated above, the gas treatment system may especially comprise a radiation unit and a hollow reflector.

Especially, the radiation unit is configured to generate radiation having one or more wavelengths selected from the wavelength range of 100-420 nm, more especially selected from the wavelength range of 100-380 nm. In embodiments, the radiation may have one or more wavelengths in the 315-380 nm range, and/or one or more wavelengths in the 280-315 nm range, and/or one or more one or more wavelengths in the 230-280 nm range, and/or one or more wavelengths in the 190-230 nm range, and/or one or more wavelengths in the 100-190 nm range. Especially, at least 80%, more especially at least about 90% of the total power of the radiation is within the wavelength range of 100-380 nm. In specific embodiments, the radiation has a centroid wavelength selected from the range of 100-315 nm. Percentages are especially based on spectral powers (in Watt). Further embodiments of the radiation unit are described below.

The term “centroid wavelength”, also indicated as lo, is known in the art, and refers to the wavelength value where half of the light energy is at shorter and half the energy is at longer wavelengths; the value is stated in nanometers (nm). It is the wavelength that divides the integral of a spectral power distribution into two equal parts as expressed by the formula /x = å l*I(l) / (å I(l), where the summation is over the wavelength range of interest, and I(l) is the spectral energy density (i.e. the integration of the product of the wavelength and the intensity over the emission band normalized to the integrated intensity). The centroid wavelength may e.g. be determined at operation conditions.

The hollow reflector is configured to receive at least part of the radiation of the radiation unit. Hence, in embodiments at least part of the radiation unit, especially a light emitting surface may be configured within the hollow reflector. Alternatively or additionally, the hollow reflector may have openings or recesses in the wall, wherein the radiation unit, or at least a light emitting surface thereof, may be configured. Hence, the hollow reflector may be configured in a light receiving relationship with the radiation unit. Especially, the radiation unit may be configured such that essentially all radiation of the radiation unit, like at least 90%, is received within the hollow reflector. Also here, percentages are especially based on spectral powers (in Watt).

The terms "radiationally coupled" or “optically coupled” may especially mean that (i) a light generating element, such as a light source, and (ii) another item or material, are associated with each other so that at least part of the radiation emitted by the light generating element is received by the item or material. In other words, the item or material is configured in a light-receiving relationship with the light generating element. At least part of the radiation of the light generating element will be received by the item or material.

Hence, in embodiments the reflective surface of the hollow reflector may be configured downstream of the radiation unit. The terms “upstream” and “downstream” relate to an arrangement of items or features relative to the propagation of the light from a light generating means (here the especially the light source), wherein relative to a first position within a beam of light from the light generating means, a second position in the beam of light closer to the light generating means is “upstream”, and a third position within the beam of light further away from the light generating means is “downstream”. In embodiments, the term “light-receiving relationship” and “downstream” may essentially be synonyms.

Especially, the hollow reflector may comprise (i) a first opening, (ii) a second opening, and (iii) a wall at least partly bridging a length (L) between the first opening and the second opening and defining a gas flow channel between the first opening and the second opening. Hence, the hollow reflector may comprise a kind of tubular shape. However, as herein further described, especially in embodiments the tube may have a smaller cross- section at the openings than in between the openings. Further, at least part of the wall has a reflective surface, reflective for the radiation. The wall may have an internal surface, which may effectively define the gas flow channel. The internal surface may have an area of which at least about 70%, such as at least about 80%, like at least about 90% is reflective for the radiation (within the wavelength range of 100-420 nm, especially within the wavelength range of 100-380 nm, such as at least within the wavelength range of 190-380 nm) of the radiation unit. Here, reflective may especially at least indicate that under perpendicular radiation at least about 80%, such as at least about 90%, even more especially at least about 95% or the radiation is reflected.

The reflective surface may e.g. be provided by a metal, like aluminum or palladium, or platinum, or gold, or osmium, especially aluminum, or by e.g. a polymeric material like Teflon type materials. Other high reflective UV coatings may also be applied. Especially, the reflective surface may be provided by a metal and may be specular reflective. Hence, especially the reflective surface is a specular reflective surface.

Especially, in embodiments the hollow reflector may comprises one or two, especially two, end parts (each) comprising (at least) a part of the reflective surface. In embodiments, one of the end parts may comprise the first opening. Alternatively or additionally, the other one of the end parts may comprising the second opening. Hence, especially the hollow reflector may comprise two end parts each comprising a part of the reflective surface, with one of the end parts comprising the first opening and the other one of the end parts comprising the second opening.

Further, in specific embodiments the reflective surface of the end part(s) may be tapered in a direction of the respective openings. Hence, at a first opening of a first end part, the cross-sectional area of the hollow reflector may be smaller than more remote from the first opening. Alternatively or additionally, at a second opening of a second end part, the cross-sectional area of the hollow reflector may be smaller than more remote from the second opening. Especially, this tapering may have a curved shape, like the shape of part of a parabola. The end part(s) may in embodiments have the shape of a hollow collimator, even more especially the shape of a hollow compound parabolic concentrator (CPC).

Further, in embodiments the reflective surface of the end parts may be facetted in a length direction of the hollow reflector. For instance, the hollow reflector may have an axis of elongation. This axis of elongation may further be the axis along which at least n/2 non-parallel planes intersect, wherein n is at least 4 and wherein n is an integer. These planes may also intersect with the wall, the (reflective) surface of the wall between two adjacent planes may be curved along the intersections with the (reflective) surface of the wall but may be non-curved along lines perpendicular to the adjacent intersections with the (reflective) surface of the wall. In this way, n facets may be provided which taper from a position remote from the respective opening to the respective opening. Further, in this way e.g. a hollow reflector may be provided having a cross-section having the shape of a (regular) n-polygon, like a square, a hexagon, an octagon, etc. However, other shapes may also be possible, such as e.g. a cross-sectional shape being a halve of a square (i.e. a rectangle), or a halve of a hexagon, or a halve of an octagon, etc. Such embodiments would provide facets having different dimensions, including one larger facet.

In contrast, facetted in a width direction of the hollow reflector would imply facets parallel to cross-sectional planes, such as parallel to a plane perpendicular to a length axis. Hence, facetted in a length direction of the hollow reflector may e.g. imply that edges between adjacent facets and the length as may defined planes parallel to the length axis. Especially, the facets may be over the entire length of the hollow reflector. Further, the cross- sectional shapes may be essentially the same over the entire length of the hollow reflector, like over at least 90% of the length. Especially, in embodiments two oppositely configured edges between respective adjacent facets may define symmetry planes.

Hence, instead of the phrase “facetted in a length direction of the hollow reflector”, in embodiments also the phrase “facetted along at least part of the length of the hollow reflector may be used. Especially, the hollow reflector may have facets having essentially the same length as the hollow reflector and having width, which may be about CL/n, wherein n is the number of facets and L is the circumferential length (or circumference). Note that at the tapering parts the circumferential length decreases with decreasing distance from the respective opening (or with decreasing distance from the middle).

Hence, the hollow reflector may in embodiments have the shape of a facetted tube, like a tube having a n-polygonal cross-section, such as a square, hexagonal, or octagonal cross-section (with the cross-section defined perpendicular to a length axis of the hollow reflector), which hollow reflector is tapering in a direction from the middle of the hollow reflector to both ends of the hollow reflector. The hollow reflector may comprise an intermediate part that is not tapering.

Hence, in embodiments the tapering may start at about the middle M and taper to the first opening or second opening, i.e. in specific embodiments a tapering over a length of about 0.5*L in each direction starting from L. However, in other embodiments the tapering may start at some distance from the middle M, like e.g. 0.1*L or 0.2*L or 0.3*L and taper therefrom to the first opening or second opening, i.e. in specific embodiments a tapering over a length of about x*L in each direction starting from L, wherein x is 0<x<0.5, especially 0.05<x<0.4, such as about 0.1<x<0.4. Therefore, the phrase “tapered in directions of the respective openings” may especially indicate in embodiments that the tapering may start at the middle, or at some distance from the middle, like e.g. at a distance 0.1*L or 0.2*L or 0.3*L from the middle, and taper therefrom to the first opening or second opening (whichever is closest).

Hence, the invention provides (also) a gas treatment system comprising a radiation unit and a hollow reflector, wherein: (A) the radiation unit is configured to generate radiation having one or more wavelengths selected from the wavelength range of 100-380 nm; (B) the hollow reflector is configured to receive at least part of the radiation of the radiation unit; wherein the hollow reflector comprises (i) a first opening, (ii) a second opening, and (iii) a wall at least partly bridging a length (L) between the first opening and the second opening and defining a gas flow channel between the first opening and the second opening; wherein at least part of the wall has a (specular) reflective surface, reflective for the radiation; and (C) the hollow reflector comprises two end parts each comprising a part of the reflective surface, with one of the end parts comprising the first opening and the other one of the end parts comprising the second opening; (wherein the end parts are at distance L of each other), wherein the reflective surface of the end parts is (a) facetted along the length L of the hollow reflector, and (b) tapered in directions of the respective openings.

Hence, especially the reflective surface of the end parts is (a) facetted in a length direction of the hollow reflector, and (b) tapered in directions of the respective openings.

As indicated above, the reflective surface of the end parts may comprises n facets. Especially, in embodiments n may be selected from the range of 4-24, and wherein n is even. Best results may be obtained with n selected from the range of 4-12, such as 6-10. Especially, in embodiments n is one of 4, 6 or 8.

Further, the gas treatment system may comprise an air flow generator configured to generate a flow of air through the hollow reflector. The air flow generator may comprise a ventilator, a pump, a blower, or other means to generate an air flow, such as a synjet. Further, the term “air flow generator” may also refer to a plurality of air flow generators.

As indicated above, the radiation of the radiation unit may substantially be trapped within the hollow reflector. This may especially be facilitated when the radiation unit provides a beam of (the) radiation having an optical axis non-parallel to the axis of elongation. Even more especially, an angle of the optical axis of a beam of radiation of the radiation unit with the axis of elongation may be chosen from the range of about 60-120°, such as selected from the range of about 75-105°, like about 90°. In this way essentially no radiation may escape from the hollow reflector without having been reflected one or more times. Hence, especially the hollow reflector and the radiation unit may be configured such that less than about 15%, such as less than about 10% of the radiation that is received by the hollow reflector (from the radiation unit) escapes therefrom without any reflection at the reflective surface, such as less than 5% of the radiation, even more especially less than 2% of the radiation. Also here, percentages are especially based on spectral powers (in Watt). Especially, the optical axis may be defined as an imaginary line that defines the path along which light propagates through a system starting from the light generating element, here especially the radiation unit.

Further, it may be beneficial when the light emitting surface of the radiation unit is configured at some distance of the opening(s). During operation of the radiation unit radiation escapes from the radiation unit via the light emitting surface. Hence, the radiation unit may have a light emitting surface, wherein during operation of the radiation unit radiation escapes from the radiation unit via the light emitting surface, wherein shortest distances (dl) from the light emitting surface to the respective openings may in specific embodiments be at least about 0.05*L, even more especially at least about 0.1 *L, like especially at least about 0.2*L. For instance, the distance to one of the openings may be about 0.1 *L and the distance to the other of the openings may be about 0.9*L. Note that this minimum distance may refer to both the distance to the first opening and the distance to the second opening. Note, however, that the actual distances may be the same or may differ.

Yet further, the end part(s) may be configured such that an acceptance angle is not too small, but also not too large. In both cases light may escape from the hollow reflector and/or may lead to less technically practical solutions. Especially, the acceptance angle in this context may be defined as the maximum angle at which incoming light can be captured by the respective first end or second end assuming the light would have to be concentrated by the hollow reflector respective first end or second end. Especially, in embodiments the respective openings of the hollow reflector may have acceptance angles (Q) individually selected from the range of 5-85°, more especially selected from the range of 15-75°. The acceptance angles for the different openings may thus be different, but may also be the same. Further, it may be desirable that a beam of radiation of the radiation unit is neither too narrow, nor too broad. A too narrow beam may imply that with a limited number of beam it may be difficult to provide a homogenous flux. A too broad beam may also complicate providing a homogeneous flux and/or may lead to light leakage. The beam width, which may be defined as the angle defined by the full width half maximum of the beam may be larger when the acceptance angle is smaller, and may be smaller when the acceptance angle is larger. Especially, it appears beneficial when b£90°-q. Hence, in embodiments the radiation unit may be configured to generate the radiation have a beam angle (b) defined by the full width half maximum of a beam of the radiation, wherein b£90°-q. For instance, in embodiments b<90°-q.

As indicated above, in embodiments shortest distances (dl) from the light emitting surface to the respective openings may in specific embodiments be at least about 0.05*L. Alternatively or additionally, an angle of the optical axis of a beam of radiation of the radiation unit with the axis of elongation may be chosen from the range of about 60-120°. Though these embodiments are desirably applied, the position of the light emitting surface of the radiation unit appears to be relatively free.

The term “radiation unit” may refer to a radiation unit configured to provide a single beam of radiation during operation of the radiation unit. The term “radiation unit” may in embodiments also refer to a radiation unit configured to provide a plurality of beams of radiation during operation of the radiation unit. Yet further, the term “radiation unit” may also refer to a plurality of radiation units, with each configured to provide one or more beams of radiation during operation of the radiation unit.

For instance, the radiation unit may comprise one or more solid state light sources. Alternatively or additionally, the radiation unit may comprise one or more excimer- based lamps. Yet, alternatively or additionally, the radiation unit may comprise a mercury based like a mercury vapor lamp. Some embodiments are further described below.

In embodiments, the gas treatment system may comprise a plurality of radiation units, wherein the radiation units comprise UV solid state light sources. Hence, in embodiments the gas treatment system may comprise one or more, especially a plurality of UV solid state light sources. The solid state light sources may comprise one or more of LEDs, diode lasers, and superluminescent diodes, especially LEDs.

One or more, especially a plurality of the UV solid state light sources may be configured in the volume defined by the wall and the first opening and second opening. One or more UV solid state light sources may be configured in the middle of the hollow reflector. Alternatively or additionally one or more UV solid state light sources may be configured at the wall of the hollow reflector. Alternatively or additionally, the wall of the hollow reflector may comprise (small) openings, in which at least part of the UV solid state light sources may be configured. For instance, the light emitting surfaces of the UV solid state light sources may be configured in the openings. Yet alternatively or additionally, the wall of the hollow reflector may comprise recessed in which at least part of the UV solid state light sources may be configured. Hence, in specific embodiments the gas treatment system may comprise a plurality of radiation units, wherein the radiation units comprise UV solid state light sources; wherein the wall comprises recesses, wherein the radiation units have light emitting surfaces configured within the recesses.

However, also a radiation unit other than a UV solid state light source may be configured in a recess. Hence, the wall of the hollow reflector may comprise one or more openings and/or one or more recesses for hosting at least part of a radiation unit, or for hosting at least parts of respective radiation units.

The beam of radiation of the radiation unit may have a Lambertian spatial intensity distribution, which may lead to a full width half maximum of about 90°. However, it may also be the case that beam has a more narrow or a broader shape. Hence, the radiation unit may further comprise optics to shape the beam, especially to provide a beam of radiation that is not too narrow, but also not too broad (see also above). Hence, in embodiments the radiation units comprise optics, wherein the radiation units comprising optics are configured to generate beams of the radiation having beam angles (b), in specific embodiments selected from the range of 30-65°.

As indicated above, in embodiments the hollow reflector may comprise two end parts. The two end parts may in embodiments substantially have shape of two hollow CPCs, which are configured to each other with their respective larger openings, leading to a kind of tubular flow channel with a middle part that has a larger cross-section and openings at the ends that have smaller cross-sections.

In alternative embodiments, the two end parts may be configured at both ends of an intermediate part. This intermediate part may in embodiments be essentially non tapering and may have a cylindrical shape, though this cylinder may also be facetted along its length direction. Further, also the intermediate part may have a reflective surface, and thereby provide part of the reflective surface of the hollow reflector.

Hence, in embodiments the hollow reflector may comprise an intermediate part, configured between the two end parts and comprising part of the reflective surface. Further, the intermediate part may (also) be facetted in the length direction of the hollow reflector. Especially, the intermediate part may comprise parallel configured facets. Further, the intermediate part may have an intermediate part length (L2) and the end parts may have end part lengths (LI). Note that the end part lengths may be the same, but are not necessarily the same.

Especially, in embodiments 0.2<L2/L1<5, such as in embodiments

0.5<L2/L1<2.

Hollow reflectors comprising an intermediate part may be more elongate than those without. At least, they may have a substantially cylindrical part, whereas those without intermediate part may taper over essentially the entire length of the hollow reflector. Though hollow reflectors are not exclusively suitable for use of elongated light sources, as also hollow reflector without an intermediate part may comprise elongated light sources, especially such hollow reflectors may host elongated light sources.

Hence, in embodiments the hollow reflector may host an elongated radiation unit having one or more light emitting surfaces configured over an elongated light emitting surface length (L4). The elongated radiation unit may in embodiments comprise an array of UV solid state light sources. The elongated radiation unit may in other embodiments comprise a discharge vessel.

Especially, such elongated radiation unit may be configured substantially in the middle of the hollow reflector. Hence, the shortest distances of the light emitting surface to the first opening and to the second opening may be about the same. Further, the light emitting surface may be configured parallel to the axis of elongated and especially at a relatively short distance therefrom, such as in the range of at maximum 0.2*r, wherein r is the radius of the hollow reflector (and which may vary over the length of the hollow reflector).

Hence, in embodiments the radiation unit comprises an elongated radiation unit having one or more light emitting surfaces configured over an elongated light emitting surface length (L4), wherein especially the elongated radiation unit is configured in the middle of the intermediate part.

Hence, in specific embodiments the gas treatment system comprises an intermediate part, configured between the two end parts and comprising part of the reflective surface; wherein the intermediate part is (also) facetted in the length direction of the hollow reflector, wherein the intermediate part comprises parallel configured facets; wherein the intermediate part has an intermediate part length (L2), wherein the end parts have end part lengths (LI), wherein 0.2<L2/L1<5; wherein the radiation unit comprises an elongated radiation unit having one or more light emitting surfaces configured over an elongated light emitting surface length (L4), wherein 0.5<L4/L2<1; wherein the elongated radiation unit is configured in the middle of the intermediate part. In embodiments, 0.1<L4/L<0.95, such as 0.2£L4/L<0.6.

In embodiments, the radiation unit may comprise a KrCl excimer discharge lamp. Such lamp may especially emit at a wavelength of about 222 nm, which may, as indicated above, be relatively safe and be relatively efficient in reducing e.g. the virus load. The 222 nm peak may have a relatively narrow band width. In addition to the about 222 nm emission, there may be a second (weaker) KrCl* peak at around 235 nm which may have a broader bandwidth. Further, there may be emission at about 258 nm. Especially, the excimer lamp is a dielectric barrier discharge (DBD) lamp. Dielectric barrier based radiation lamps are known in the art, and are for instance described in US2010/0164410; U. Kogelschatz, Dielectric-Barrier Discharges: Their History, Discharge Physics, and Industrial Applications. Plasma Chemistry and Plasma Processing 23, 1-46, https://doi.Org/10.1023/A:1022470901385: WO 2006/006139; and R. Brandenburg,

Dielectric barrier discharges: progress on plasma sources and on the understanding of regimes and single filaments, Plasma Sources Science and Technology, Vol. 26, No. 5, 1-29, including corrigendum, which four disclosures are herein incorporated by reference.

Especially, dielectric-barrier discharge (DBD) is the electrical discharge between two electrodes separated by an insulating dielectric barrier. DBD devices can be made in many configurations, typically planar, using parallel plates separated by a dielectric or cylindrical, using coaxial plates with a dielectric tube between them. Other shapes may also be possible. Especially, herein the elongated radiation unit may comprise an axial design or a coaxial design, as known in the art.

Hence, in specific embodiments the radiation may have intensity at one or more wavelengths within the wavelength range of 210-235 nm.

Some further embodiments are described below.

The hollow cylinder, whether or not comprising an intermediate part may have a facetted shape over a substantial part of its length, like at least about 90%.

In specific embodiments, the hollow reflector has a cross-sectional shape having 4, 6, or 8 sides. Such configurations may provide most homogenous fluence rates.

As indicated above, the hollow reflector may be a kind of tubular flow channel with a middle part that has a larger cross-section and openings at the ends that have smaller cross-sections. In specific embodiments, the hollow reflector may have a largest cross-section having a largest cross-sectional area (A3), wherein the openings have opening areas (Al), wherein in specific embodiments 0.95<A3/A1<15, such as in specific embodiments 1.05<A3/A1<12. Especially, in embodiments A3/Al=l/(sin(0)) ² .

The term “light source” may also refer to a plurality of the same or a plurality of different light sources. Hence, e.g. the term “excimer discharge based light source” may also refer to a plurality of excimer discharge based light sources.

The gas treatment system may comprise a control system or may be functionally coupled to the control system (see also below).

In yet a further aspect, the invention provides an air control system comprising a conduit system comprising one or more conduits and a control system configured to control an airflow in the one or more conduits, wherein the air control system further comprises the gas treatment system as defined herein, wherein in an operational mode of the air control system at least part of the airflow flows through the hollow reflector while providing the radiation. For instance, the air control system may be a ventilation system or a climate control system.

The control system may control the radiation unit of the gas treatment system. The control system may control the radiation unit of the air control system. For instance, the control system may control one or more of intensity of the radiation and radiation time of the radiation, like according to a time schedule. The control system may control the airflow of the air control system.

The term “controlling” and similar terms especially refer at least to determining the behavior or supervising the running of an element. Hence, herein “controlling” and similar terms may e.g. refer to imposing behavior to the element (determining the behavior or supervising the running of an element), etc., such as e.g. measuring, displaying, actuating, opening, shifting, changing temperature, etc.. Beyond that, the term “controlling” and similar terms may additionally include monitoring. Hence, the term “controlling” and similar terms may include imposing behavior on an element and also imposing behavior on an element and monitoring the element. The controlling of the element can be done with a control system, which may also be indicated as “controller”. The control system and the element may thus at least temporarily, or permanently, functionally be coupled. The element may comprise the control system. In embodiments, the control system and element may not be physically coupled. Control can be done via wired and/or wireless control. The term “control system” may also refer to a plurality of different control systems, which especially are functionally coupled, and of which e.g. one control system may be a master control system and one or more others may be slave control systems. A control system may comprise or may be functionally coupled to a user interface.

The control system may also be configured to receive and execute instructions form a remote control. In embodiments, the control system may be controlled via an App on a device, such as a portable device, like a Smartphone or iPhone, a tablet, etc.. The device is thus not necessarily coupled to the lighting system, but may be (temporarily) functionally coupled to the lighting system.

Hence, in embodiments the control system may (also) be configured to be controlled by an App on a remote device. In such embodiments the control system of the lighting system may be a slave control system or control in a slave mode. For instance, the lighting system may be identifiable with a code, especially a unique code for the respective lighting system. The control system of the lighting system may be configured to be controlled by an external control system which has access to the lighting system on the basis of knowledge (input by a user interface of with an optical sensor (e.g. QR code reader) of the (unique) code. The lighting system may also comprise means for communicating with other systems or devices, such as on the basis of Bluetooth, WIFI, LiFi, ZigBee, BLE or WiMAX, or another wireless technology.

The system, or apparatus, or device may execute an action in a “mode” or “operation mode” or “mode of operation”. Likewise, in a method an action or stage, or step may be executed in a “mode” or “operation mode” or “mode of operation” or “operational mode”. The term “mode” may also be indicated as “controlling mode”. This does not exclude that the system, or apparatus, or device may also be adapted for providing another controlling mode, or a plurality of other controlling modes. Likewise, this may not exclude that before executing the mode and/or after executing the mode one or more other modes may be executed.

However, in embodiments a control system may be available, that is adapted to provide at least the controlling mode. Would other modes be available, the choice of such modes may especially be executed via a user interface, though other options, like executing a mode in dependence of a sensor signal or a (time) scheme, may also be possible. The operation mode may in embodiments also refer to a system, or apparatus, or device, that can only operate in a single operation mode (i.e. “on”, without further tunability).

Hence, in embodiments, the control system may control in dependence of one or more of an input signal of a user interface, a sensor signal (of a sensor), and a timer. The term “timer” may refer to a clock and/or a predetermined time scheme. For instance, the control system may control the radiation unit and/or the gas flow in dependence of a sensor. The sensor may e.g. be configured to generate a sensor signal in dependence of the composition of the gas that is flowing to the hollow reflector or that is flowing away from the hollow reflector.

In embodiments, the sensor may comprise one or more of a gas sensor, a volatile organic compound sensor, and a pathogen sensor. Alternatively or additionally, the sensor may comprise one or more of an airflow sensor, a temperature sensor, and a humidity sensor. The pathogen sensor may comprise a sensor for one or more of bacteria, viruses, and spores. The term “sensor” may also refer to a plurality of (different types ol) sensors.

In further embodiments, the gas treatment system may further comprise one or more filters, e.g. to filter particles, like e.g. particulate matter in air. Alternatively or additionally, the gas treatment system may comprise an adsorbent, e.g. to adsorb odors, etc.

In specific embodiments the air control system may be an office air control system comprising a plurality of the conduits, wherein the plurality of conduits comprise a plurality of air inlets and air outlets.

The gas treatment system and/or the air control system may e.g. be used in hospitals, retail, offices, industry, schools, hospitality areas (like e.g. hotels), sporting halls, and other internal building applications, such as cinemas, theaters, etc. The gas treatment system may be applied for large area air cleaning, etc.

In yet a further embodiment, the invention provides a gas treatment system comprising a radiation unit and a hollow reflector, wherein: (A) the radiation unit is configured to generate radiation having one or more wavelengths selected from the wavelength range of 100-380 nm; (B) the hollow reflector is configured to receive at least part of the radiation of the radiation unit; wherein the hollow reflector comprises (i) a first opening, (ii) a second opening, and (iii) a wall at least partly bridging a length (L) between the first opening and the second opening and defining a gas flow channel between the first opening and the second opening; wherein at least part of the wall has a reflective surface, reflective for the radiation; and (C) the hollow reflector is (a) facetted in a length direction of the hollow reflector, and (b) optionally tapered from one of the first opening and second opening to the other one of the first opening and the second opening. Such hollow reflector may have the shape of a collector.

In embodiments, the hollow reflector may comprises a tubular shape and may have an axis of elongation. In embodiments, the beam of the radiation may have an optical axis non parallel to the axis of elongation.

In embodiments, the reflective surface may have a reflectivity of at least 80%.

In embodiments, the respective openings of the hollow reflector may have acceptance angles (Q) individually selected from the range of 15-75°.

In embodiments, the light emitting surface of the radiation unit may be configured within the hollow reflector.

In embodiments, the hollow reflector and the radiation unit may be configured such that less than 15% of the radiation received by the hollow reflector from the radiation unit escapes without any reflection at the reflective surface.

In embodiments, the gas treatment system may be configured to treat air within said hollow reflector.

In yet a further aspect, the invention provides a method for treating air, the method comprising flowing air through the hollow reflector as defined herein while providing the radiation as defined herein to the hollow reflector. In embodiments, treating may refer to disinfecting. In this way, viruses and/or bacteria may be killed using radiation in a (relatively) safe way for humans, as the radiation may be contained in the hollow reflector.

The terms “light” and “radiation” may herein interchangeably be used.

BRIEF DESCRIPTION OF THE DRAWINGS

Embodiments of the invention will now be described, by way of example only, with reference to the accompanying schematic drawings in which corresponding reference symbols indicate corresponding parts, and in which:

Fig. la-le schematically depict some embodiments of the system; on the x- axis in Fig. le, angle b is indicated (in degrees) and on the y-axis the escaped (UV) power (IE) in % of the power;

Fig. 2 schematically depicts a further embodiment;

Figs. 3a-3d schematically depict some further embodiments; and

Figs. 4a-4b schematically depict embodiments of the (air treatment) system of the invention and applications thereof.

The schematic drawings are not necessarily to scale. DETAILED DESCRIPTION OF THE EMBODIMENTS

Fig. la schematically depicts an embodiment of a gas treatment system 1000 comprising a radiation unit 100 and a hollow reflector 400.

The radiation unit 100 is especially configured to generate radiation 101, in embodiments having one or more wavelengths selected from the wavelength range of 100- 380 nm.

The hollow reflector 400 is especially configured to receive at least part of the radiation 101 of the radiation unit 100. Here, a plurality of radiation units 100 are schematically depicted. The radiation units 100 may comprise UV solid state light sources.

The hollow reflector 400 may comprises a first opening 401 and a second opening 402. The hollow reflector 400 may also comprise a wall 405 at least partly bridging a length L between the first opening 401 and the second opening 402 and defining a gas flow channel 430 between the first opening 401 and the second opening 402. At least part of the wall 405 may have a (specular) reflective surface 407, (specular) reflective for the radiation 101

The hollow reflector 400 may comprise two end parts 410 each comprising a part of the reflective surface 407, with one of the end parts 410 comprising the first opening 401 and the other one of the end parts 410 comprising the second opening 402. The end parts may be hollow CPC-like elements.

Fig. la may be a cross-sectional view parallel to the length axis LA of a facetted hollow reflector 400. For some details about the facets, see also Fig. lb.

The tapering directions are indicated with references tdl and td2, and may be in the direction of the respective openings 401,402, and parallel to an axis of elongation LA. The tapering may be in a direction from a middle M of the hollow reflector to the first opening 401 in the case of one of the end parts 410 and from the middle M of the hollow reflector to the second opening 402 in the case of the other end part 410.

In Fig. la, the tapering starts at some distance from M and taper therefrom to the first opening or second opening. Here, the tapering is over a length of x*L in each direction starting from L, wherein about 0.1<x<0.4. Hence, in this schematically depicted embodiment the tapering starts at some distance from the middle, and tapers therefrom to the first opening 401 or second opening 402 (whichever is closest). Here, the tapering start between about 10-30% from the middle left from the middle, and tapers to the first opening

401, and 10-30% from the middle right from the middle, and tapers to the second opening

402. The faceting directions are indicated with references fdl and fd2, and may (also) be in the direction of the respective openings 401,402, and parallel to an axis of elongation LA.

As schematically depicted in Fig. lb, which shows a cross-section of one of the end parts, or the optional intermediate part 420 (see below), the reflective surface 407 of the end parts 410 may be (a) facetted in a length direction of the hollow reflector 400, and may be (b) tapered in directions of the respective openings 401,402.

The arrow in at first opening 401 indicates an air flow entering the hollow reflector 400 (to be treated) and the arrow out at second opening 402 indicates the air flow (of treated air) leaving the hollow reflector 400.

Fig. lb also shows eight edges between sets of adjacent facets. As can be seen, in the present schematically depicted embodiment opposite edges may define n/2 symmetry planes (though more symmetry planes may be available (e.g. via the middles of the facets).

Fig. lb schematically depicts cross-sections which may be taken at several positions along the length axis LA of the embodiment of Fig. la. At some positions, the facets may be indicated with reference 425, i.e. the facets of the intermediate part 420, and some facets may be indicated with references 435, i.e. the facets of the end parts 410. Hence, in a single schematical drawing, different cross-sections are depicted. Note that the dimensions, however, may vary over the length L of the hollow reflector. Hence, except for the dimension, the cross-sectional shape may essentially be the same over the entire length L of the hollow reflector. Note that cross-section here, refer to cross-sections perpendicular to the length axis LA.

Referring to Figs la and lb, the reflective surface 407 of the end parts 410 may comprise n facets 435, wherein n is selected from the range of 4-24, and wherein n is even. Here, by way of example an octagon is schematically depicted.

Further, the gas treatment system 1000, more especially the hollow reflector 400, may comprise an intermediate part 420, configured between the two end parts 410 and comprising part of the reflective surface 407.

The intermediate part 420 may (also) be facetted in the length direction of the hollow reflector 400. Hence, in embodiments the intermediate part 420 comprises parallel configured facets 425; see also the cross-section in Fig. lb, which may be the cross-section of the intermediate part 420 and/or of the end parts 410, not taking into account possible size differences. The intermediate part 420 may have an intermediate part length L2. The end parts 410 may have end part lengths LI. In embodiments, 0.2<L2/L1<5.

L=L1+L1+L2, wherein Ll+Ll refers to the end part lengths of the respective end parts 410,420.

LA refers to a longitudinal axis. References D1 refer to the respective diameters of the first opening 401 and second opening 402.

The radiation 101 provided by the radiation unit 100 may have a centroid wavelength selected from the range of 100-315 nm.

The radiation unit 100 may have a light emitting surface 105. During operation of the radiation unit 100 radiation 101 may escape from the radiation unit 100 via the light emitting surface 105. The light emitting surface 105 may have shortest distances dl from the light emitting surface 105 to the respective openings 401,402 is at least 0.1 *L.

In an example, and referring to e.g. the embodiment schematically depicted in Figs la-lb, the optical cavity may consists of three connected parts having a length Li, L2 and Li. The parts with lengths Li and Li may consists of a reflective compound parabolic concentrator (CPC). In most cases, these two CPC’s have the same geometrical properties. The shape of a CPC, depending on the acceptance angle (Q), is extensively described in the literature. The entrance of the first CPC (Li) is characterized by area Ai and width diameter Di. The exit of the first CPC is characterized by area A3 and width diameter D3. The entrance of the second CPC is also characterized by area Ai and width diameter Di. The exit of the second CPC is characterized by area Ai and width Diameter di.

The acceptance angle Q is also indicated in relation to the first part 410, as if it is a separate concentrator. Hence, the first part and the second part are especially defined by the tapering wall 405.

Square, hexagonal and octagonal shapes are especially suitable for good light mixing. Fig. lc shows a square cross section as a second example. The hollow, reflective mixing cavity contains an array of LEDs. The LEDs emit UV radiation between angles -b and +b.

A flow of (contaminated) is guided through the optical cavity during the disinfection process (see also Fig. la). The average fluence rate (W/m ² ) and the residence time (s) of the air inside the cavity determines the dose (J/m ² ) used to deactivate pathogens in the air flow. Fig. lc provides an embodiment in which a specific situation, all light is trapped in the cavity. Fig. lc shows a mixing cavity composed of two reflective CPC’s and five LEDs (50 mW UV per LED). The acceptance angle Q of both CPC’s is 30 degrees.

Figs. Id and le shows the relation between the maximum emission angle b and the acceptance angle Q of the CPC’s. It turns out that when Lambertian LEDs are installed (b=90 deg., i.e., b>90-q), some UV radiation leaks out of the cavity. When b<90-q, all emitted light “remains” in the cavity, i.e., light travels between the reflective walls until finally all light is absorbed (R _Waii <100%). The long optical path is helpful in the deactivation of pathogens in the air flow. Fig. le show the leakage of radiation from the cavity as a function of the beam angle b (HWHM). The leakage of UV power divided by the installed UV power is plotted on the y-axis.

Referring to Fig. Id, in embodiment II essentially all light (UV radiation) is trapped, whereas in example 1, part of the light (UV radiation) is not trapped and escapes from the hollow reflector. These plots give an indication of the uniformity of UV power inside the cavity.

The examples above illustrate a wide range of parameters to optimize disinfection performance (dose): volume CPC (V), acceptance angle CPC (Q), reflectance CPC material, LED placement, number of LEDs, UV power per LED and air flow rate. The beam angle (b) of the LEDs can be optimized by a small lens or CPC on top of the LED. The lens or CPC can be made from a transparent material such as quartz (SiCE), borosilicate glass or silicones. The reflective material for the CPC can be aluminum sheet from e.g., Alanod corporation. Mirror surfaces can also be made by a thin layer of aluminum applied on a smooth solid material shape by physical vapor deposition.

Especially, in embodiments the respective openings 401,402 of the hollow reflector 400 may have acceptance angles Q individually selected from the range of 5-85°, especially selected from the range of 15-75°.

As can be derived from the above, in embodiments the radiation unit 100 may be configured to generate the radiation 101 have a beam angle b defined by the full width half maximum of a beam 111 of the radiation 101, wherein b£90°-q.

In embodiments, the hollow reflector 400 may have a largest cross-section having a largest cross-sectional area A3, wherein the openings 401,402 have opening areas Al, wherein 0.95<A3/A1<15. Referring to Fig. 2, the radiation unit 100 may comprise an elongated radiation unit 100 having one or more light emitting surfaces 105 configured over an elongated light emitting surface length L4.

Here, an embodiment is depicted with also an (optional) intermediate part 420. Hence, in embodiments the gas treatment system 1000, especially the hollow reflector, may comprise an intermediate part 420, configured between the two end parts 410 and comprising part of the reflective surface 407. As indicated above, the intermediate part 420 may (also) be facetted in the length direction of the hollow reflector 400. The intermediate part 420 may comprises parallel configured facets 425. The intermediate part 420 has an intermediate part length L2. The end parts 410 have end part lengths LI. In embodiments, 0.2<L2/L1<5. In specific embodiments, 0.5<L4/L2<1. Especially, the elongated radiation unit 100 is configured in the middle of the intermediate part 420.

The radiation unit 100 may have an essentially tubular shape, having an axial design or a coaxial design.

In embodiments, the radiation 101 has intensity at one or more wavelengths within the wavelength range of 210-235 nm.

Fig. 2 also schematically depicts an embodiment of two connected square CPC’s having an acceptance angle (Q) of 30 degrees.

In an example, the following parameters are selected: Di=2.5 mm, D3=5 mm, L2=0, L _I =13 mm, L4=20 mm (radius light emitting tube: 0.1 mm, 1 W UV power is emitted at 254 nm). The inner (specular) reflectance of the optical cavity is 95%. It was found that only 0.068 W UV power (~7%) escapes through air inlet (401) area Ai and air exit (402) area Ai (loss). 6.59 W is detected on the detector plane as indicated in Fig. 3. The fluence rate detected on a small sphere (r=0.05 mm) is 0.064 W/mm ² (coordinates spherical detector: x=0, y=1.25 mm, z=0 mm).

The curved disinfection chamber in Fig. 2 is compared with a square geometry having the same value for Ai and A3 (i.e. a non-tapering tube having a square cross-section.). The following parameters are selected: Ddi2=2.5 mm, D3=5 mm, L ₂ =26 mm, L _I =L2=0 mm, L4=20 mm (radius light emitting tube: 0.1 mm, 1 W UV power is emitted at 254 nm). The inner (specular) reflectance of the optical cavity is 95%. It was found that 0.351 W UV power (-35%) escapes through air inlet area Ai and air exit area A2 (loss). 4.60 W is detected on the detector plane. The fluence rate detected on a small sphere (r=0.05mm) is 0.035 W/mm ² (coordinates spherical detector: x=0, y=1.25 mm, z=0 mm). These results show a dramatic improvement when a curved optical cavity, composed of two CPC’s, is applied. In the example presented, the fluence rate is almost doubled and the loss of UV through the air inlet/outlet is reduced by a factor 5. Another advantage is that the shape of the UV chamber fits well with the air flow velocity profiles expected. Using a box-like geometry, “dead comers” are expected in which air velocity is low.

Fig. 3a schematically depict a number of embodiments of cross-sections, with 8, 6, or 4 sides (in embodiments I, II, and III, respectively). Hence, in specific embodiments the hollow reflector 400 may have a cross-sectional shape having 4, 6, or 8 sides. As indicated above, over the length L of the hollow reflector, the shape of the cross-sections may essentially stay constant.

Referring to Fig. 3b, in embodiments the wall 405 may comprise a recess 415. The radiation unit 100 may have a light emitting surface 105 configured within the recess 415. Reference d2 indicates the depth of the recess 415, with the reflective surface 407 at a depth d2=0. The light emitting surface 105 may be at a non-zero depth, and may thus be recessed. However, the light emitting surface 105 may also be at essentially the same height as the reflective surface 407.

Fig. 3b schematically depicts an embodiment comprising a plurality of radiation units 100, wherein the radiation units 100 comprise UV solid state light sources; wherein the wall 405 comprises recesses 415, wherein the radiation units 100 have light emitting surfaces 105 configured within the recesses 415. Reference 540 refers to a support for the radiation unit 100, such as a PCB. In this way, the PCB may be configured external of the hollow reflector 400.

Fig. 3c schematically depict further embodiments how a desirable beam shape may be provided. For instance, in embodiment I the beam shape of the beam of radiation 101 may be such that the beam angle b may be fine for the application. Embodiments II and III show the use of optics 130, such as a reflector or a massive reflector, respectively. Beam angles b may be selected from the range of 30-65°. Hence, in embodiments the radiation units 100 comprise optics 130, wherein the radiation units 100 comprising optics 130 are configured to generate beams 111 of the radiation 101 having beam angles b selected from the range of 30-65°.

Fig. 3d schematically depicts part of the hollow reflector 400, would a hollow reflector 400 be obtained on the bases of a hollow reflector with a square cross-section of which only a halve is taken (but would of course all surfaces be reflective). A perspective view is shown in embodiment I and two cross-sections are shown in Fig. 3d embodiment II.

Referring to Fig. 4a, the system 1000 may comprise an air flow generator 510 configured to generate a flow of air through the hollow reflector 400. Further, the system 1000 may comprise a control system 300, or may be functionally coupled thereto.

Hence, Fig. 4a effectively schematically depicts an embodiment of an air control system 2000 comprising a conduit system 2100 comprising one or more conduits 2130 and a control system 300 configured to control an airflow in the one or more conduits 2130. The air control system 2000 further comprises the gas treatment system 1000. In an operational mode of the air control system 2000 at least part of the airflow flows through the hollow reflector 400 while providing the radiation 101.

Reference 310 indicate sensors.

In embodiments, the air control system 2000 may be an office air control system comprising a plurality of the conduits 2130, wherein the plurality of conduits 2130 comprise a plurality of air inlets 2131 and air outlets 2132.

Fig. 4b schematically depict a number of applications including a handheld air control system (device), which may be placed on e.g. a desk, another device which may be connected to the mains, and which may e.g. be associated to the desk. Yet, by way of example the air control system 2000 may be integrated in e.g. a ceiling 160. Further, a variant is shown (on the right) with a number of reflector elements configured in series. Reference 150 indicates a lighting device, such as a luminaire, which may in embodiments also be integrated in the ceiling 160.

Hence, the invention also provides a method for treating air, the method comprising flowing air through the hollow reflector 400 while providing the radiation to the hollow reflector 400.

The term “plurality” refers to two or more.

The terms “substantially” or “essentially” herein, and similar terms, will be understood by the person skilled in the art. The terms “substantially” or “essentially” may also include embodiments with “entirely”, “completely”, “all”, etc. Hence, in embodiments the adjective substantially or essentially may also be removed. Where applicable, the term “substantially” or the term “essentially” may also relate to 90% or higher, such as 95% or higher, especially 99% or higher, even more especially 99.5% or higher, including 100%.

The term “comprise” also includes embodiments wherein the term “comprises” means “consists of’. The term “and/or” especially relates to one or more of the items mentioned before and after “and/or”. For instance, a phrase “item 1 and/or item 2” and similar phrases may relate to one or more of item 1 and item 2. The term "comprising" may in an embodiment refer to "consisting of but may in another embodiment also refer to "containing at least the defined species and optionally one or more other species".

Furthermore, the terms first, second, third and the like in the description and in the claims, are used for distinguishing between similar elements and not necessarily for describing a sequential or chronological order. It is to be understood that the terms so used are interchangeable under appropriate circumstances and that the embodiments of the invention described herein are capable of operation in other sequences than described or illustrated herein.

The devices, apparatus, or systems may herein amongst others be described during operation. As will be clear to the person skilled in the art, the invention is not limited to methods of operation, or devices, apparatus, or systems in operation.

It should be noted that the above-mentioned embodiments illustrate rather than limit the invention, and that those skilled in the art will be able to design many alternative embodiments without departing from the scope of the appended claims.

In the claims, any reference signs placed between parentheses shall not be construed as limiting the claim.

Use of the verb "to comprise" and its conjugations does not exclude the presence of elements or steps other than those stated in a claim. Unless the context clearly requires otherwise, throughout the description and the claims, the words “comprise”, “comprising”, and the like are to be construed in an inclusive sense as opposed to an exclusive or exhaustive sense; that is to say, in the sense of “including, but not limited to”.

The article "a" or "an" preceding an element does not exclude the presence of a plurality of such elements.

The invention may be implemented by means of hardware comprising several distinct elements, and by means of a suitably programmed computer. In a device claim, or an apparatus claim, or a system claim, enumerating several means, several of these means may be embodied by one and the same item of hardware. The mere fact that certain measures are recited in mutually different dependent claims does not indicate that a combination of these measures cannot be used to advantage.

The invention also provides a control system that may control the device, apparatus, or system, or that may execute the herein described method or process. Yet further, the invention also provides a computer program product, when running on a computer which is functionally coupled to or comprised by the device, apparatus, or system, controls one or more controllable elements of such device, apparatus, or system.

The invention further applies to a device, apparatus, or system comprising one or more of the characterizing features described in the description and/or shown in the attached drawings. The invention further pertains to a method or process comprising one or more of the characterizing features described in the description and/or shown in the attached drawings.

The various aspects discussed in this patent can be combined in order to provide additional advantages. Further, the person skilled in the art will understand that embodiments can be combined, and that also more than two embodiments can be combined. Furthermore, some of the features can form the basis for one or more divisional applications.