Ceiling light

Description

[0001] The invention relates to a luminaire for installation in a ceiling, in particular for installation in a suspended ceiling, a luminaire system comprising such a luminaire and a further luminaire system.

[0002] Luminaires of the type mentioned above are generally known from the prior art. These are generally installed in ceilings, particularly suspended ceilings, to emit light towards the underside of the ceiling or to illuminate the space below the luminaire (an office room or other rooms). To cool such luminaires, it is known that air from the space below the luminaire flows through the luminaire or past the sides of the luminaire to absorb the heat that the luminaire emits during operation. Finally, the air from the luminaire flows into the suspended ceiling area or space above the ceiling. The air heated by the luminaire collects in this space, as this space is essentially sealed off from the space below the luminaire.

[0003] It has now been shown in the state of the art that the space above the ceiling, i.e., the suspended ceiling area, continuously heats up due to the accumulating and heated air there. Consequently, efficient air circulation is no longer possible, meaning the luminaire cannot be adequately cooled. This also impairs the service life of such a luminaire due to insufficient cooling.

[0004] A luminaire is known, for example, from JP 2012 230761 A. A lighting system is known, for example, from US 2008 / 165535 A1.

[0005] The invention is therefore based on the object of overcoming the aforementioned disadvantages of the prior art. In particular, it is an object of the invention to provide a luminaire of the type mentioned above that is more effectively cooled.

[0006] The object is achieved according to the invention for the luminaire and the luminaire systems by the features of the independent claims. Advantageous further developments are the subject of the dependent claims.

[0007] A luminaire according to the invention for installation in a ceiling, in particular for installation in a suspended ceiling, comprises: a housing with (at least) one inlet duct for cooling a light source accommodated in the housing by means of air flowing in the inlet duct due to free convection in the direction of a main flow direction. The inlet duct has a first air inlet opening for admitting the flowing air into the inlet duct and a first air outlet opening for discharging the air flowing in the inlet duct from the inlet duct. The luminaire further comprises at least one exhaust duct. The exhaust duct has a second air inlet opening for admitting the air flowing from the first air outlet opening into the exhaust duct and a second air outlet opening for discharging the air flowing in the exhaust duct from the exhaust duct. The second air outlet opening is offset (arranged) relative to the first air inlet opening in the direction of the main flow direction.

[0008] The housing is designed in such a way that the cooling of the lamp contained within it occurs without forced convection, i.e., passively, without flow machines such as fans or the like. Rather, cooling occurs by means of free convection, or more precisely, by means of the so-called chimney effect: heating the air within the inlet channel creates density differences, causing air to flow or be drawn into the inlet channel vertically (i.e., in the main flow direction or against gravity). The air thus flowing past the lamp absorbs the heat emitted by the lamp and transports it outside the housing via the first air outlet opening, thereby cooling the lamp.

[0009] Due to the offset of the second air outlet opening relative to the first air inlet opening - i.e. because the first air inlet opening is intentionally not flush with the second air outlet opening - a pressure difference is created between the second air outlet opening and the first air inlet opening. This pressure difference then causes air to circulate through the inlet duct and the exhaust air duct, allowing cold, fresh air from the environment to flow unhindered into the inlet duct. The air circulates because the air at the first air inlet opening has lower potential energy than at the second air outlet opening and therefore higher kinetic energy. This air circulation allows the air heated up by the operation of the lamp to be dissipated, preventing heated air from building up, particularly on the side of the first air outlet opening.

[0010] As a result, the cooling of the luminaire is improved overall, especially because no heated air can accumulate at the second air outlet opening due to the offset and the resulting gradation.

[0011] According to the present invention, the exhaust air duct comprises a preferably plate-shaped element provided laterally from the housing, wherein the element delimits a portion of the exhaust air duct and a portion of the second air outlet opening. Consequently, the exhaust air duct can be easily formed by the element, thus reducing the assembly effort for the luminaire. A plate-shaped element (flank) is particularly advantageous because such an element is easy to manufacture. If the element also delimits a portion of the second air outlet opening, additional steps for providing the respective air outlet opening can be omitted.

[0012] Advantageously, a wall region of the housing delimits part of the exhaust air duct. Thus, the exhaust air duct is partially formed by the housing, providing an overall compact luminaire. Furthermore, it is preferred if the wall region also delimits part of the second air outlet opening. This allows for easy provision of the respective air outlet opening. Furthermore, this brings the respective air outlet opening even closer to the housing, allowing the luminaire to be designed to be compact overall.

[0013] The exhaust air duct, namely the element, has a through-opening that forms the second air inlet. Since a through-opening can be easily provided, the second air inlet can be easily provided. This means that, in particular, the manufacturing effort for the second air inlet is reduced.

[0014] It is preferred if the second air inlet opening or the through-opening is elongated and / or designed as a slot. Such an air inlet opening can be easily provided. Due to the preferably elongated design of the slot or the second air inlet opening, more air can also flow through the second air inlet opening into the exhaust air duct, thus further improving the cooling of the luminaire and the removal of the air heated by the operation of the lamp.

[0015] The luminaire preferably has two exhaust air ducts as described above. This allows even more air heated by the operation of the lamp to be removed, thus further improving the cooling of the luminaire. Preferably, the two exhaust ducts are located to the side of the housing. In other words, the housing is preferably arranged between the exhaust ducts. This allows the heated air to be removed efficiently.

[0016] The housing can further comprise at least one light emission opening for emitting the light emitted by a light source accommodated in the housing, wherein the first air inlet opening is provided laterally of the light emission opening. Alternatively or additionally, the first air inlet opening can partially or completely surround the light emission opening, preferably rotationally symmetrically, for example, arcuately or circularly. This is particularly true when the light emission opening is rotationally symmetrical, for example, round, so that the axes of rotation of the first air inlet opening and the light emission opening are preferably substantially congruent. Thus, the housing and consequently also the luminaire can be designed compactly.Furthermore, the inlet channel can be directly adjacent to the components defining the light emission opening, such as the lamp, a component accommodating the lamp, and / or optical elements such as a reflector or a lens, so that heat emitted by the lamp can be effectively transported away from the lamp by the air flowing in the inlet channel. Cooling of the lamp is thus further improved.

[0017] The housing can have at least two, preferably three or more, particularly preferably five or more than five inlet channels, each having a first air inlet opening. In a preferred embodiment, one of the at least one light emission opening is provided between each two adjacent first air inlet openings, as seen in a plan view of the housing. Alternatively or additionally, the first air inlet openings can each partially or completely surround one of the at least one light emission opening, preferably rotationally symmetrically. This allows the amount of air flowing into or through the housing to be increased, which consequently benefits the cooling of the luminaire or the illuminant.

[0018] The first air outlet opening can be provided centrally relative to the housing, as viewed from above. Thus, the air flowing out of the first air outlet opening can flow evenly to the sides of the housing, improving air circulation and thus cooling of the luminaire.

[0019] Alternatively or additionally, the first air outlet opening can be located on the side of the housing. This allows the first air outlet opening to open directly into the exhaust air duct, which benefits efficient cooling of the luminaire.

[0020] The invention further relates to a lighting system comprising a ceiling, for example a suspended ceiling, and a luminaire as described above. The luminaire is provided in the ceiling in such a way that the air flowing in the inlet duct due to free convection is admitted from a front side of the ceiling via the first air inlet opening into the inlet duct and is discharged (removed) from the inlet duct to a rear side of the ceiling via the first air outlet opening. The luminaire is further provided in the ceiling in such a way that the air flowing from the first air outlet opening and thus located on the rear side of the ceiling is admitted into the exhaust air duct via the second air inlet opening and discharged from the exhaust air duct to the front side of the ceiling via the second air outlet opening.

[0021] In other words, the second air outlet opening is offset relative to the first air inlet opening in a direction from the front to the back of the ceiling; the first air inlet opening thus protrudes from the front of the ceiling. This, in turn, creates the air circulation described above.

[0022] As a result of the air circulation, which leads through the inlet duct and the exhaust duct, among other things, the air heated on the back of the ceiling and by the operation of the luminaire is discharged to the front of the ceiling. The back of the ceiling is usually an essentially enclosed space, such as the area between a (suspended) ceiling and a ceiling supporting the (suspended) ceiling. The front of the ceiling is usually the space to be illuminated by the luminaire. As a result of the air circulation, no heated air can build up on the back of the ceiling or in the essentially enclosed space on the back of the ceiling, so that free convection for cooling the lamp in the housing is not interrupted, thus ensuring efficient cooling of the luminaire.Furthermore, the heated air discharged from the second air outlet is guided along the surface of the front of the ceiling and thus effectively directed away from the luminaire.

[0023] According to a further aspect, the invention relates to a lighting system comprising a ceiling and a light fixture installed in the ceiling. The light fixture has a housing with an inlet duct for cooling a light source accommodated in the housing by means of air flowing in the inlet duct due to free convection in a main flow direction. The inlet duct has a first air inlet opening for admitting the flowing air from a front side of the ceiling into the inlet duct and a first air outlet opening for discharging the air flowing in the inlet duct from the inlet duct to a rear side of the ceiling. The lighting system, preferably the ceiling, has at least one exhaust air duct.The exhaust air duct has a second air inlet opening for admitting the air flowing from the first air outlet opening, which is thus located at the rear of the ceiling, into the exhaust air duct, and a second air outlet opening for discharging the air flowing in the exhaust air duct from the exhaust air duct to the front of the ceiling. The second air outlet opening is offset (arranged) relative to the first air inlet opening in the direction of the main flow direction. The above-mentioned advantages for more efficient cooling of the luminaire or the luminaire system apply analogously to this luminaire system. Furthermore, by providing the exhaust air duct in the ceiling, the luminaire itself can be designed more compactly.

[0024] In a non-claimed embodiment, the exhaust air duct is preferably formed integrally with the ceiling. This is particularly advantageous for the simple provision of the exhaust air duct in the ceiling.

[0025] According to the present invention, a built-in element for installation in the ceiling is provided, wherein the built-in element comprises the exhaust air duct.

[0026] Thus, for example, the exhaust air duct can be replaced depending on the application. Furthermore, such a built-in element has additional structures, for example the (plate-shaped) element described above, for the manufacturing and / or flow optimization of the luminaire or the luminaire system. The exhaust air duct is preferably designed as a through-opening, in particular as a slot.

[0027] in the ceiling. This is particularly advantageous for easily locating the exhaust air duct and its openings in the ceiling.

[0028] The ceiling can have two or more exhaust ducts. This allows even more of the air heated by the lamp to be removed, further improving the cooling of the luminaire.

[0029] The invention is described below by way of example with reference to the figures, which illustrate advantageous embodiments of the invention. The drawings show: Figure 1a a schematic sectional view of a first embodiment of the luminaire or luminaire system according to the invention with schematically indicated circulation of the air for cooling the luminaire; Figure 1b which in Figure 1a The lamp shown is a top view from below; Figure 2 an embodiment of the first embodiment of the luminaire according to the invention in a perspective view from above; Figure 3 a schematic sectional view of the Figure 1a and 1b shown luminaire system with velocity profile of the air for cooling the luminaire; Figure 4 an embodiment of a second embodiment of the luminaire according to the invention in a perspective view from above; Figure 5a schematic sectional view of an embodiment of a lighting system with the light according to the second embodiment with a velocity profile of the air for cooling the light.

[0030] The figures each show an example of a luminaire 1 or a luminaire system. As can be seen particularly in the Figure 1a , 3 and 5 As can be seen, the luminaire 1 can be used, for example, for installation in a ceiling 2.

[0031] As in Figure 1aAs can be seen, for the installation of the luminaire 1 in the ceiling 2, the ceiling 2 can have an opening 3 into which the luminaire 1 can be provided or inserted. The luminaire 1 can be fastened in the opening 3 using fastening means not shown in detail. Suitable fastening means are, in particular, force-fitting and / or form-fitting fastening means, such as screw or clip connections. The opening 3 preferably has an elongated shape, for example in the form of a slot.

[0032] The ceiling 2 has a front side and a back side which faces away from the front side. The front side of the ceiling 2 is generally directed towards the room to be illuminated by the luminaire 1, i.e. the front side of the ceiling 2 is a side of the ceiling 2 which is visible from the room to be illuminated. The back side of the ceiling 2 is generally not visible from the room to be illuminated. The back side of the ceiling 2 can, for example, be directed towards a room R which is not visible from the room to be illuminated, for example because the room R (also called the suspended ceiling area or installation space) contains cabling or other (electrical and / or electronic) components for the operation and / or installation of the luminaire 1 which should be concealed if possible. The ceiling 2 can, for example, be the side wall of a shaft for receiving and operating the luminaire 1.However, it may also be the case that ceiling 2 is a ceiling supported by another ceiling D via corresponding support means 4. Ceiling 2 may, for example, be a suspended ceiling. The other ceiling D may, for example, be a (concrete or steel) ceiling of a house or other property. Ceiling 2, another ceiling D, and support means 4 may thus, for example, form the essentially enclosed space R provided on the rear side of ceiling 2.

[0033] The luminaire 1 preferably has a shape corresponding to the opening 3, for example, an elongated shape. However, the luminaire 1 is not limited to an elongated shape, but can, for example, be flat or similar, in particular round, as seen in a top view of the luminaire 1.

[0034] The luminaire 1 further comprises a housing 5, which is designed to accommodate at least one illuminant 6, for example an LED. The housing 5 can in particular be designed to accommodate a plurality of illuminants 6. The housing 5 can further be designed to accommodate further (electrical and / or electronic) components of the luminaire 1, for example cabling and / or an operating device for operating the illuminant 6. The illuminant 6 is provided in the housing 5 such that the illuminant 6 can emit light via a light emission opening 61 in the housing 5, in particular in the direction of the space below the ceiling 2. The light emission opening 61 optionally has a translucent cover. The light emission opening 61 preferably has a rectangular (e.g. square), round, oval and / or polygonal shape when viewed from above.The housing 5 preferably has a shape corresponding to the opening 3, i.e., preferably an elongated shape. For example, the housing 5 can be box-shaped.

[0035] As in particular Figure 1b As can be seen, the housing 5 can also have several, in particular two, three, or more than three, light-emitting openings 61. Each of the light-emitting openings 61 can in turn have a lighting means 6 as described above. The light-emitting openings 61 are preferably arranged in a row.

[0036] The housing 5 further comprises an inlet channel with a first air inlet opening 7 or - as particularly shown in Figure 1brecognizable - several, i.e. at least two, preferably three or four, particularly preferably five or more than five inlet channels, each with a first air inlet opening 7 for cooling the illuminant 6 and preferably the other components of the luminaire 1 by means of air flowing in the (respective) inlet channel due to free convection in the direction of a main flow direction. In the housing 5 shown as an example in the figures, the main flow direction corresponds to a direction from the front of the ceiling 2 to the back of the ceiling 2, i.e., for example, a vertical direction. The heat-emitting components provided in the housing 5, i.e., in particular, the illuminant 6, cause density differences in the inlet channel by heating the air contained therein, so that air flows in the inlet channel in a vertical direction according to the chimney effect.The flowing air will therefore absorb the heat emitted by the lamp 6 and transport it away from the lamp 6, so that the lamp 1 or the lamp 6 is cooled.

[0037] In the exemplary embodiment of the housing 5 shown in the figures, the first air inlet opening 7 is provided laterally from the light emission opening 61. If preferably several inlet channels or air inlet openings 7 are provided, it is preferred if, as seen in plan view of the housing 5, at least one of the at least one light emission opening 61 is provided at least between two adjacent air inlet openings 7. Furthermore, as in Figure 1bAs can be seen, an air inlet opening 7 can be provided between a wall of the housing 5 and a light emission opening 61 adjacent to the wall of the housing 5. For example, the two outermost light emission openings 61, each adjacent to a wall of the housing 5, together with the respective wall of the housing 5 form two air inlet openings 7. In other words, the wall of the housing 5 preferably forms part of the inlet channel or the inlet channel is partially designed as a housing (part). However, the invention is not limited to such an inlet channel. It must only be ensured that the air flowing through the inlet channel flows in such a way that it absorbs the heat emitted at least by the illuminant 6, for example by the air flowing through the inlet channel flowing directly or indirectly around the illuminant 6.The first air inlet opening 7 is preferably provided on the front side of the housing 5, for example on the side of the room to be illuminated.

[0038] The inlet duct further comprises a first air outlet opening 8 for discharging the air flowing in the inlet duct from the inlet duct. As shown in Figure 4As can be seen, the first air outlet opening 8 can be provided laterally in the housing 5. For example, two first air outlet openings 8 can be provided laterally in the housing 5, preferably such that the lighting means is provided between the air outlet openings 8. Preferably, the first air outlet opening 8 is provided in the housing 5 such that it opens directly into the exhaust air duct 9, as described below. The at least one first air outlet opening 8 can be elongated, for example such that the at least one air outlet opening 8 extends in the direction of the longitudinal extent of the housing 5. It is particularly preferred if the air outlet opening 8 is designed as a slot.

[0039] Alternatively or additionally, it may be provided that - as exemplified in Figure 1 and 2recognizable - seen in a top view of the housing 5, at least one first air outlet opening 81 is provided centrally with respect to the housing 5. Several, in particular four, air outlet openings 81 may also be provided transversely, for example perpendicularly to the (longitudinal) extension of the lamp 1. The respective air outlet opening 81 may, for example, be designed as a slot. The air outlet openings 81 may be provided uniformly along the extension of the lamp 1. Figure 3 The corresponding velocity profile of the resulting air circulation can be seen. When comparing the Figure 3 with the Figure 5 , which represents the speed profile of the embodiment according to Figure 4 , it can be seen that the flow of air flowing (upwards) out of the housing 5 for cooling the lamp 6 can be increased.

[0040] The luminaire 1 further comprises at least one exhaust air duct 9. The exhaust air duct 9 is preferably provided laterally of the housing 5. It is preferred if the luminaire 1 has two or only two exhaust air ducts 9, which are preferably provided laterally of the housing 5. The housing 5 can be provided between the two exhaust air ducts 9.

[0041] For the sake of simplicity, only one of the two exhaust air ducts 9 is described in detail below. The description of this exhaust air duct 9 therefore applies analogously to the other of the two exhaust air ducts 9.

[0042] According to the present invention, the exhaust air duct 9 has a preferably plate-shaped element 10 provided laterally from the housing, which delimits a part of the exhaust air duct.

[0043] In the figures, the element 10 is shown as a plate-shaped example. However, the element 10 can have any desired flat and / or elongated shape. In particular, the element 10 can be made of a thin-walled material such as sheet metal. The element 10 is preferably designed so that it can be fastened to the ceiling 2, preferably via a flat side of the element 10. The fastening can be effected using a fastening means, for example using a material-locking, force-locking and / or form-locking fastening means, in particular using screws. Furthermore, the element 10 can be connected to the housing 5 via fastening means as described above, for example in such a way that when the luminaire 1 is mounted on the ceiling 2, the element 10 is simultaneously fastened to the ceiling 2.

[0044] Furthermore, as shown by way of example in the figures, a wall region of the housing 5 can delimit a portion of the exhaust air duct 9. The exhaust air duct 9 can thus be formed, for example, by arranging the element 10 adjacent to the wall region of the housing 5; in other words, the exhaust air duct 9 can be the gap provided between the element 10 and the housing 5.

[0045] The exhaust air duct 9 has a second air inlet opening for admitting the air flowing from the first air outlet opening 8, 81 into the exhaust air duct 9. The figures, in particular the Figure 2 and 4 , show that the second air inlet opening is formed by a through opening 11.

[0046] The through-opening 11 is preferably provided on the rear side of the ceiling 2, for example, in the room R. It is preferred if the through-opening 11 is provided near the rear side of the ceiling 2. The through-opening 11 can be an elongated through-opening, in particular extending in the direction of the longitudinal extent of the luminaire 1 or the housing 5. In particular, the through-opening 11 can be designed as an (elongated) slot. It is preferred if the through-opening 11 is formed in the element 10.

[0047] Furthermore, the exhaust air duct 9 has a second air outlet opening 12. The exhaust air duct 9 is preferably formed only between the second air inlet opening 11 and the second air outlet opening 12. The second air outlet opening 12 is preferably provided on the front side of the ceiling 2. The air flowing or provided in the exhaust air duct 9 can be discharged from the exhaust air duct 9 via the second air outlet opening 12, i.e., for example, into the room to be illuminated. The second air outlet opening 12 can, as shown by way of example in the figures, be provided such that the element 10 and / or the wall region of the housing 5 forms part of the second air outlet opening 12. This means that an opening in the gap provided between the housing 5 and the element 10 can form the second air outlet opening 12. The second air outlet opening 12 thus preferably has an elongated shape or a shape corresponding to the luminaire 1 or the housing 5.

[0048] According to the invention, it is now provided that the second air outlet opening 12 is offset relative to the first air inlet opening 7 in the direction of the main flow direction, i.e., for example, in the vertical direction (i.e., upwards in the figures). In the exemplary embodiment shown in the figures, this offset is formed by the first air inlet opening 7 protruding slightly, i.e., for example, a few millimeters, from the front of the ceiling 2 or from the room R. It is preferred if the first air inlet opening 7 protrudes from the second air outlet opening 12 and / or from the front of the ceiling 2 at an offset of 1 mm to 20 mm, more preferably from 2 mm to 10 mm, particularly preferably from 4 mm, or of up to 50%, more preferably up to 25%, particularly preferably from 5% to 10%, for example 8% of the height of the luminaire 1. The (total) height of the luminaire 1 is preferably 50 mm.Such an offset can achieve an effective cooling flow without affecting the visual appearance of the luminaire 1. In other words, the offset creates a gradation from the first air inlet opening 7 to the second air outlet opening 12. Due to the offset, a pressure difference is thus generated between the first air inlet opening 7 and the second air outlet opening 12, which causes air to flow as shown in FIG. Figure 1 circulates as indicated by the arrows.

[0049] In particular Figure 1shows that the air circulation leads both through the inlet duct, for example through the housing 5, and through the exhaust air duct 9. In the exemplary embodiment of the lighting system shown in the figures, the air circulation thus discharges the air accumulating in the room R and heated by operation of at least the lamp 6 to below the lamp, i.e. in particular into the room to be illuminated. In the room to be illuminated, the discharged and heated air rises again, but does not return to the room R because of the air circulation, but is guided away from the lamp 1 along the front of the ceiling 2. In this way, the lamp 1, i.e. in particular the lamp 6, can be cooled efficiently. In particular, it has been observed that the temperature of the lamp 1 can be reduced by more than 8°C.

[0050] Alternatively, however, the exhaust air duct can also be provided separately from the luminaire 1, for example in the ceiling 2. What has been said with regard to the exhaust air duct 9 therefore applies analogously to an exhaust air duct provided in the ceiling 2, unless otherwise described below.

[0051] An exhaust air duct formed in the ceiling 2 can be arranged in the ceiling 2, in a not claimed embodiment, for example

[0052] be formed integrally. Alternatively, however, according to the present invention, it is also provided that a built-in element, for example designed corresponding to the element 10 described above, is provided in the ceiling 2 and comprises the exhaust air duct.

[0053] The exhaust air duct is preferably designed as a through-hole in the ceiling. The exhaust air duct can therefore be provided simply, for example, by drilling a through-hole in the ceiling 2. The through-hole can be elongated and / or designed as a slot.

[0054] Preferably, two or more of the exhaust air ducts described above are provided in the ceiling 2. For example, the two exhaust air ducts can be arranged such that the luminaire 1 is located between these exhaust air ducts. The two or more exhaust air ducts can also be arranged around the luminaire 1, in particular evenly distributed around the luminaire 1.

[0055] The invention is not limited to the illustrated embodiments. All features described above or shown in the figures can be advantageously combined with one another as desired within the scope of the invention.

Claims

1. Luminaire (1) for installation in a ceiling (2), in particular for installation in a suspended ceiling, comprising - a housing (5) with an inlet duct for cooling a lamp (6) accommodated in the housing by means of air flowing in the inlet duct in the direction of a main flow direction due to free convection, wherein the inlet duct has ∘ a first air inlet opening (7) for admitting the flowing air into the inlet duct and ∘ a first air outlet opening (8, 81) for discharging the air flowing in the inlet duct from the inlet duct, and ∘ at least one exhaust air duct (9) with ∘ a second air inlet opening (11) for admitting the air flowing from the first air outlet opening (8, 81) into the exhaust air duct (9) and ∘ a second air outlet opening (12) for discharging the air flowing in the exhaust air duct (9) from the exhaust air duct (9), wherein the second air outlet opening (12) is offset relative to the first air inlet opening (7) in the direction of the main flow direction, wherein the exhaust air duct (9) has an element (10) provided laterally with respect to the housing (5), wherein the element (10) delimits a part of the exhaust air duct (9) and a part of the second air outlet opening (12), and characterized in that the element (10) has a through opening (11) which forms the second air inlet opening (11).

2. Luminaire (1) according to claim 1, wherein the element (10) is plate-shaped.

3. Luminaire (1) according to claim 1 or 2, wherein a wall region of the housing (5) delimits a part of the exhaust air duct (9) and preferably a part of the second air outlet opening (12).

4. Luminaire (1) according to any of the preceding claims, wherein the second air inlet opening (11) is a slit.

5. Luminaire (1) according to any of the preceding claims, comprising two exhaust air ducts (9) which are preferably provided laterally with respect to the housing (5).

6. Luminaire (1) according to any of the preceding claims, wherein the housing (5) has at least one light emission opening (61) for emitting the light emitted by a lamp (6) accommodated in the housing (5), wherein the first air inlet opening (7) is provided laterally with respect to the light emission opening (61) and / or partially or completely surrounds the light emission opening (61), preferably rotationally symmetrically.

7. Luminaire (1) according to claim 6, wherein the housing (5) has at least two, preferably three or more, particularly preferably five or more than five inlet ducts, each having a first air inlet opening (7), wherein preferably, as seen in plan view of the housing (5), one of the at least one light emission openings (61) is provided between two adjacent first air inlet openings (7), and / or wherein the first air inlet openings (7) each partially or completely surround one of the at least one light emitting openings (61), preferably rotationally symmetrically.

8. Luminaire (1) according to any of the preceding claims, wherein the first air outlet opening (8, 81) is provided centrally with respect to the housing (5) and / or laterally in the housing (5), as seen in plan view of the housing (5).

9. Luminaire system comprising a ceiling (2), for example a suspended ceiling, and a luminaire (1) according to any of the preceding claims, wherein the luminaire (1) is provided in the ceiling (2) in such a way that - the air flowing in the inlet duct due to free convection is admitted into the inlet duct from a front side of the ceiling (2) via the first air inlet opening (7) and is discharged from the inlet duct to a rear side of the ceiling (2) via the first air outlet opening (8, 81), and that - the air flowing from the first air inlet opening (8, 81), and thus located on the rear side of the ceiling (2), is admitted into the exhaust air duct (9) via the second air inlet opening (11) and is discharged from the exhaust air duct (9) to the front side of the ceiling (2) via the second air outlet opening (12).

10. Luminaire system, comprising a ceiling (2), and a luminaire which is installed in the ceiling (2) and comprises a housing (5) with an inlet duct for cooling a lamp (6) accommodated in the housing (5) by means of air flowing in the inlet duct in the direction of a main flow direction due to free convection, wherein the inlet duct has - a first air inlet opening (7) for admitting the flowing air from a front side of the ceiling (2) into the inlet duct and - a first air outlet opening (8, 81) for discharging the air flowing in the inlet duct from the inlet duct to a rear side of the ceiling (2), and wherein the luminaire system, preferably the ceiling (2), further comprises at least one exhaust air duct, wherein the exhaust air duct has: - a second air inlet opening for admitting the air flowing from the first air outlet opening, and thus located on the rear side of the ceiling, into the exhaust air duct, and - a second air outlet opening for discharging the air flowing in the exhaust air duct from the exhaust air duct to the front side of the ceiling, wherein the second air outlet opening is offset relative to the first air inlet opening (7) in the direction of the main flow direction, further comprising a mounting element for installation in the ceiling, wherein the mounting element comprises the exhaust air duct, characterized in that the built-in element has additional structures, namely an element (10) provided laterally with respect to the housing (5), wherein the element (10) delimits a part of the exhaust air duct and a part of the second air outlet opening, and wherein the element (10) has a through opening (11) which forms the second air inlet opening.

11. Luminaire system according to claim 10, wherein the exhaust air duct is designed as a through opening, preferably as a slit, in the ceiling (2).

12. Luminaire system according to claim 10 or 11, comprising at least two exhaust air ducts.