LIGHTING DEVICE FOR PROVIDING LIGHT TO BE USED IN A PHOTOCHEMICAL REACTION

Abstract

The invention relates to a lighting device, to the use of the lighting device in a photochemical reaction, to a photochemical reactor and to a method used by the lighting device. The lighting device 100 comprises an LED unit 110 configured to emit light 114 to be used in the photochemical reaction, a housing 120 configured to house the LED unit, wherein at least a part of the housing is transparent for light to be used in the photochemical reaction, wherein the housing is configured to contain a dielectric liquid transparent for light generated by the LED unit such that it is in direct contact with at least a part of the light emitting side of the LED unit, and a liquid movement arrangement 130 configured to support a movement of the dielectric liquid such that the dielectric liquid transports heat produced by the LED unit away from the LED unit.

Claims

1-17. (canceled)

18. A lighting device for providing light (114) to be used in a photochemical reaction, wherein the lighting device (100, 100′) comprises: an LED unit (110) configured to emit light (114) to be used in the photochemical reaction, a housing (120, 120′) configured to house the LED unit (110), wherein at least a part of the housing (120, 120′) is transparent for light (114) to be used in the photochemical reaction, wherein the housing (120, 120′) is configured to contain a dielectric liquid transparent for light (114) generated by the LED unit (110) such that it is in direct contact with at least a part of a light emitting side of the LED unit, and a liquid movement arrangement (130) configured to support a movement of the dielectric liquid such that the dielectric liquid transports heat produced by the LED unit (110) away from the LED unit (110).

19. The lighting device according to claim 18, wherein the liquid movement arrangement (130) comprises a liquid flow source (142) or is configured to be connected to a liquid flow source (142) configured to move the dielectric liquid.

20. The lighting device according to claim 18, wherein the liquid movement arrangement (130) comprises a cooling unit outside of the housing (120, 120′) or is adapted to be connected to a cooling unit configured for cooling the dielectric liquid.

21. The lighting device according to claim 18, wherein the lighting device (100, 100′) further comprises the dielectric liquid in the housing (120, 120′).

22. The lighting device according to claim 21, wherein the dielectric liquid comprises a refraction coefficient substantially similar to the refraction coefficient of the transparent part of the housing (120, 120′).

23. The lighting device according to claim 21, wherein the dielectric liquid is adapted to be movable by the liquid movement arrangement (130) in a temperature range from -35° C. to 150° C.

24. The lighting device according to claim 21, wherein the dielectric liquid is silicone oil or mineral oil.

25. The lighting device according to claim 18, wherein the LED unit (110) comprises an LED (111) and a mounting board (112), wherein the LED (111) is mounted to a first side of the mounting board (112), and wherein the mounting board (112) forms at least a part of the housing (120) such that the dielectric liquid is in direct contact with the LED (111) on the first side of the mounting board (112).

26. The lighting device according to claim 18, wherein the LED unit (110) comprises an LED (111) and a mounting board (112), wherein the LED (111) is mounted to a first side of the mounting board (112), and wherein the mounting board (112) is arranged in the housing (120′) such that the dielectric liquid is in direct contact with at least a part of the first side of the mounting board (112) and at least a part of a second side of the mounting board (112) opposite the first side.

27. The lighting device according to claim 25, wherein an additional cooling unit is provided on a second side of the mounting board (112) opposite the first side such that heat is transported away from the second side of the mounting board (112).

28. Use of a lighting device according to claim 18 as a light source in a photochemical reaction, wherein the light (114) emitted by the lighting device (100, 100′) is used to trigger and/or maintain a photochemical reaction in a medium provided in a photochemical reactor (300, 400).

29. A photochemical reactor, wherein the reactor (300, 400) comprises: a reaction chamber configured to contain a reaction mixture as basis for the photochemical reaction, and a lighting device (100, 100′) according to claim 18, wherein the light (114) emitted by the lighting device (100, 100′) triggers and/or maintains the photochemical reaction of the reaction mixture.

30. The reactor according to claim 29, wherein the reactor comprises a first conduit (310) and a second conduit (320), wherein the first conduit (310) is arranged inside the second conduit (320), wherein the reaction chamber is formed by the first conduit (310) and the lighting device (100, 100′) is arranged in the volume between the first conduit (310) and the second conduit (320) such that the light (114) provided by the lighting device (100, 100′) is radiated into the first conduit (310), or wherein the reaction chamber is formed by at least a part of the volume between the first conduit (310) and the second conduit (320) and the lighting device (100, 100′) is arranged inside the first conduit (310) such that the light (114) provided by the lighting device (100, 100′) is radiated into the volume between the first conduit (310) and the second conduit (320).

31. The reactor according to claim 30, wherein at least a part of the first conduit (310) forms at least a part of the housing (120, 120′) of the lighting device.

32. The reactor according to claim 31, wherein the reactor comprises the first conduit (310, 642) and the second conduit (320, 641), wherein the lighting device (100, 100′) is arranged in the volume between the first conduit (320, 641) and the second conduit (320, 641), wherein at least a part of the second conduit forms at least a part of the housing (120, 120′) of the lighting device, wherein the reactor comprises a liquid movement arrangement comprising a ring nozzle (600), wherein the ring nozzle (600) is arranged at at least one end of the first and second conduit (310, 320, 641, 642) such that the ring nozzle (600) closes the volume (643) between the first and second conduit (310, 320, 641, 642) at the end, wherein the ring nozzle (600) is adapted to guide the dielectric liquid from a connector arrangement (620), which is adapted to provide the dielectric liquid to the ring nozzle (600), to the volume between the first and second conduit (310, 320, 641, 642) comprising the lighting device (100, 100′).

33. The reactor according to claim 32, wherein the ring nozzle (600) comprises a circular volume (610) with a plurality of openings (611) that connect the volume (643) containing the lighting device (100, 100′) with the circular volume (610) of the ring nozzle (600), wherein the connector arrangement (620) is adapted to provide the dielectric liquid into the circular volume (610) and wherein the circular volume (610) comprises a shape that is narrower at a side of the conduits than at an opposite side.

34. A method for transporting heat away from an LED unit (110), wherein the method (500) comprises the steps of: providing (510) a housing (120, 120′) that is configured to house the LED unit (110), providing (520) a dielectric liquid in the housing (120, 120′) such that it is in direct contact with at least a part of a light emitting side of the of the LED unit (110), and moving (530) the dielectric liquid in order to remove heat from the LED unit (110).

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0048] In the following drawings:

[0049] FIGS. 1a and 1b show schematically and exemplarily an embodiment of a lighting device,

[0050] FIGS. 2a and 2b show schematically and exemplarily an arrangement of a lighting device with respect to a photochemical reaction chamber,

[0051] FIGS. 3a to 4d show schematically and exemplarily an embodiment of a photochemical reactor comprising a lighting device,

[0052] FIG. 5 shows a flowchart exemplarily illustrating an embodiment of a method for cooling an LED unit provided in the lighting device, and

[0053] FIGS. 6 and 7 show schematically and exemplarily an example of a ring nozzle that can be utilized with a chemical reactor.

DETAILED DESCRIPTION OF EMBODIMENTS

[0054] FIG. 1a shows schematically and exemplarily an embodiment of a lighting device to be used in a photochemical reaction. The lighting device 100 comprises an LED unit 110, a housing 120 and a liquid movement arrangement 130.

[0055] In this exemplary embodiment, the LED unit 110 comprises LED 111 and a mounting board 112, wherein the mounting board 112 is adapted to provide means that allow to connect LED 111 to a power source 113. The mounting board 112 hence refers in this example to a circuit board adapted to provide the necessary circuitry for driving a high-power LED 111. However, in other embodiments, the mounting board can simply refer to a board on which LED 111 can be mounted, wherein the contacting means for contacting LED 111 to a power source 113 are not provided as part of the mounting board 112. The LED 111 is adapted to provide light 114 that can be used in a photochemical reaction.

[0056] The housing 120 of lighting device 100 is in this embodiment configured to house the LED unit 110 such that the mounting board 112 forms a lower part of the housing 120. Further, in this embodiment the housing comprises a transparent part, for instance, the upper half of the housing 120, which is transparent for light 114 that should be used in a photochemical reaction. Moreover, the housing 120 is configured such that at least a light emitting part of the LED unit 110 is in direct contact with a dielectric liquid, when present in the housing 120. In particular, the LED 111 and a part of the first side of the mounting board 112 on which the LED 111 is mounted and which can be considered as the light emitting side of the LED unit in this embodiment are in direct contact with the dielectric liquid.

[0057] In this example the housing is already provided with the dielectric liquid. However, the dielectric liquid can also be provided as part of a liquid flow source to the housing when the housing is connected to the liquid flow source. The dielectric liquid provided in the housing 120 of the lighting device 100 is preferably a silicone oil or a mineral oil. Generally, the provided dielectric oil is chosen to be transparent at least for the light 114 provided by the LED unit 110 that should be used in the photochemical reaction. In particular, the dielectric liquid provided in the housing of the lighting device 100 does not substantially absorb or reflect light of a wavelength provided by the LED unit 110 that should be used in the photochemical reaction. In a preferred embodiment, the dielectric liquid is substantially transparent for the complete light, i.e. for the complete spectrum, emitted by the LED unit 110. It is preferred that the dielectric liquid provided in the housing 120 comprises a substantially similar refraction coefficient as the transparent part of the housing 120. In particular, a refraction coefficient lying between 1.35 and 1.55 is preferred for the dielectric liquid, since most transparent housing materials will also comprise a refraction coefficient in this interval.

[0058] Experiments have shown that, in particular, a dielectric liquid chosen from the group containing Element14 PDMS High Viscosity Oils, Baysilone® Fluids M and KORASILON® Oils M are suitable as dielectric liquid. However, also other silicone or mineral oils might be utilized as dielectric liquids in the lighting device 100 and might comprise characteristics that can be used to advantage.

[0059] In this example the housing 120 is integrated with the liquid movement arrangement 130. The liquid movement arrangement 130 supports the movement of the dielectric liquid through the housing 120 such that the dielectric liquid can transport head produced by the LED unit away from the LED unit 110. In this exemplary embodiment, the liquid movement arrangement 130 comprises means for supporting an inflow 131 and an outflow 132 of a dielectric liquid with respect to the housing 120 such that the dielectric liquid can come into direct contact with the LED unit 110. In this exemplary embodiment, the dielectric liquid can come into direct contact with the LED 111 and a first side of the mounting board 112 on which the LED 111 is mounted. In the embodiment shown in FIG. 1a, the dielectric liquid comes into contact with the complete first side of the mounting board 112. However, in other embodiments the housing 120 can be configured such that the dielectric liquid only comes into contact with a part of the first side of the mounting board 112, only a part of the LED 111 or a part of both the first side of the mounting board 112 and a part of the LED 111.

[0060] In the embodiment shown in FIG. 1a, the liquid movement arrangement 130 comprises connection means that allow to connect the lighting device 100 to a liquid flow source 140. The liquid flow source 140 comprises a pump 142 providing a movement to the dielectric liquid and further the necessary circuitry for transporting the dielectric liquid from and to the connecting means of the liquid movement arrangement 130. However, in an alternative embodiment, the liquid flow source 140 can also directly be integrated as part of the liquid movement arrangement 130 into the lighting device 100, wherein in this case connecting means for connecting to the liquid flow source 140 can be omitted.

[0061] Further, a cooling unit, not shown in FIG. 1a, can be provided, for instance, as part of the liquid flow source. In this case, the cooling unit can be part of the pump 142 and/or can be part of the circuitry 141.

[0062] When used for providing light to a photochemical reaction chamber, the LED 111 is powered by the power source 113 and produces light 114 provided to the photochemical reactor. Additionally, the LED 111 produces heat that has to be transported away from the LED 111. In order to transport the heat away from the LED 111, the dielectric liquid is pumped by pump 142 through the circuitry 141 into the liquid movement arrangement 130 and the housing 120 such that it comes into direct contact with LED 111 and can transport heat produced by LED 111 away, for instance, to a cooling unit provided in circuitry 141, before again being pumped by pump 142 into the housing 120.

[0063] FIG. 1b shows a modification of the embodiment of the lighting device shown in FIG. 1a. In particular, elements of the lighting device 100′ that can be provided similar to elements already described with respect to lighting device 100 are provided with the same reference signs. The main difference between the lighting device 100 shown in FIG. 1a and the lighting device 100′ shown in FIG. 1b refers to the configuration of the housing 120′ being integrated with the liquid movement arrangement 130′. In particular, in this exemplary embodiment, the housing 120′ and the liquid movement arrangement 130′ are configured such that the dielectric liquid can come into contact with at least a part of the first side of the mounting board 112 on which the LED 111 is mounted and additionally with at least a part of a second side of the mounting board 112 opposite the first side. Thus, in this embodiment, incoming dielectric liquid 131′ can flow as indicated by arrows 133 along the first side and the second side to transport heat away from the LED unit 110 when flowing out 132′ of the housing 120′. This embodiment has the advantage that the LED unit 110 can be cooled even more effectively, since the surface area in which the LED unit 110 is in direct contact with a dielectric liquid is increased.

[0064] In both embodiments of the lighting device 100 and 100′, the mounting board 112 can comprise a mounting plate on which, for instance, a circuit board on which the LED 111 is mounted, can be provided, wherein such a mounting plate is preferably made from a metal. Alternatively, the mounting plate can be provided as not being part of the LED unit 110 but as an optional addition to the LED unit 110. This is in particular advantageous in embodiments in which the lighting device 100, 100′ comprises more than one LED unit 110, wherein in this case all LED units 110 can be mounted on the mounting plate which might then form, for instance, in the embodiment shown in FIG. 1a, a part of the housing 120 housing the plurality of LED units 110.

[0065] FIGS. 2a and 2b show an exemplary arrangement and configuration of lighting devices 100, 100′ providing light to a reaction chamber 210 in which a medium is provided in which a photochemical reaction should be triggered and/or maintained by the light provided by lighting devices 100, 100′. FIGS. 2a and 2b show in particular schematic cross sections through the arrangement of the lighting device and the reaction chamber.

[0066] In the arrangement 200 shown in FIG. 2a, two lighting devices based on the principles explained with respect to lighting device 100′ of FIG. 1b are provided. The lighting devices 100′ are provided in the form of half cylinders comprising a plurality of LED units 110. In accordance with the principles disclosed with respect to FIG. 1b showing lighting device 100′, the LED units 110 are arranged in the housing of lighting device 100′ in such a manner that the dielectric liquid can come into contact with a first and a second side of a mounting board of the LED units 110. Preferably, the liquid movement arrangement is configured in this embodiment such that the dielectric liquid provided within the half cylinder part of the lighting device 110 can flow in a general direction parallel to a centerline of the half cylinder, wherein the flow of the dielectric liquid in the half cylinder can be realized as a laminar or a turbulent flow.

[0067] In contrast to the arrangement 200 shown in FIG. 2a, the arrangement 200′ shown in FIG. 2b utilizes lighting devices 100 based on the principles described with respect to FIG. 1a. In particular, in the lighting devices 100 utilized in the arrangement 200′, the LED units 110 are mounted on a mounting plate 220 that forms the outer part of the housing of the lighting device 100. Preferably, the mounting plate 220 is made from a metal, wherein the LED units 110 are arranged on the mounting plate 220 in a manner such that the LED is in thermal contact with the mounting plate 220. This embodiment allows to provide an additional cooling, for instance, by providing a cooling circuitry within the mounting plate 220, to the LED units 110.

[0068] Both arrangements 200 and 200′ allow to provide light emitted by the LED units 110 through a transparent part of the housing into reaction chamber 210, wherein in this arrangement the reaction chamber 210 is at least partly formed from a transparent material.

[0069] FIGS. 3a to 4d show different embodiments of a photochemical reactor integrated with a lighting device in accordance with the principles explained with respect to FIGS. 1a and 1b. In FIGS. 3a to 3d, the lighting device is integrated with a reaction chamber for forming the photochemical reactor by providing a first conduit 310 and a second conduit 320. Preferably, the first conduit 310 and the second conduit 320 are cylinder-shaped, wherein the first conduit 310 is provided inside the second conduit 320 such that the centerlines of the first conduit 310 and the second conduit 320 coincide. Moreover, in the exemplary embodiment show in FIGS. 3a to 3d, at least a part of the housing of the lighting device is formed by at least a part of the first conduit 310. For example, in FIG. 3a, at least parts of the housing of the lighting device 100′ are formed by the first conduit 310 and the second conduit 320.

[0070] In FIGS. 3a and 3b, the lighting devices are based on the principle of the lighting device 100′ as explained with respect to FIG. 1b. In particular, in both embodiments, the LED units 110 are arranged inside the housing of the lighting device 100′, such that a dielectric liquid is in direct contact with a first side of the mounting board and a second side of the mounting board of the LED units 110.

[0071] In the photochemical reactor 300 shown in FIG. 3a, the first conduit further forms at least part of the reaction chamber in which a reaction medium can be provided in which a photochemical reaction should be triggered by the light provided by the lighting device 100′. The LED units 110 are then provided within the volume formed between the first, i.e. inner, conduit 310 and the second, i.e. outer, conduit 320 such that they can emit light in the direction of the first conduit 310. Since, in this embodiment, the first conduit 310 and the second conduit 320 form at least part of the housing of the lighting device 100′, the liquid movement arrangement can be adapted such that the dielectric liquid is supported to move through the volume formed between the first conduit 310 and the second conduit 320.

[0072] FIG. 3b shows an alternative arrangement of a photochemical reactor 300′ in which the housing of the lighting device 100′ is mainly formed by the first conduit 310. Thus, in this case the liquid movement arrangement is configured to support a liquid flow through the first conduit 310, in a general direction parallel to a centerline of the first conduit 310. In this exemplary embodiment, the reaction chamber is formed by the volume between the first conduit 310 and the second conduit 320. The LED units 110 in the lighting device 100′ formed at least partially by the first conduit 310 are thus arranged such that the light emitted by the LED units 110 is provided to the outside of the first conduit 310 and thus into the volume between the first conduit 310 and the second conduit 320. In this embodiment, at least the parts of the first conduit 310 directly above the LED units 110 are formed from a transparent material.

[0073] FIGS. 3c and 3d show photochemical reactors 300″ and 300‴ similar to the photochemical reactors 300 and 300′, wherein the lighting device integrated with the reaction chamber 310 in this case is based on the principles described with respect to lighting device 100 shown in FIG. 1a. In particular, in these embodiments the LED units 110 are mounted on a mounting plate 330, preferably, made at least partly from metal.

[0074] In the photochemical reactor 300″ exemplarily shown in FIG. 3c, the mounting plate 330 forms at least part of the wall of the second conduit 320. The mounting plate 330 can be adapted, for instance, to provide a further cooling to the LED units 110, for instance, by providing cooling circuitry within the mounting plate 330. In the embodiment of the photochemical reactor 300‴ that is similar to the photochemical reactor 300′ shown in FIG. 3b, the mounting plate 330 is provided in the form of a cylinder on which the LED units 110 are mounted. Also in this embodiment, the mounting plate 330′ can be provided with a cooling unit, for instance, with a cooling circuitry within the cylinder formed by the mounting plate 330′.

[0075] FIGS. 4a to 4d refer to modified embodiments of photochemical reactors shown in FIGS. 3a to 3d, respectively. The main difference between the photochemical reactors 400, 400′, 400″ and 400‴ and the photochemical reactors 300, 300′, 300″ and 300‴ refers to providing a third conduit 340 such that an additional volume is formed between the first conduit 310 and the third conduit 340. In photochemical reactors 400 and 400″ referring to photochemical reactors 300 and 300″, the LED units 110 are then formed in the volume provided by the third conduit 340 and the second conduit 320. Thus, in these embodiments the third conduit 340 and the second conduit 320 can be regarded as forming at least part of the housing of the lighting device 100. In all embodiments shown in FIGS. 4a to 4d of the photochemical reactor, the third conduit 340 forming the additional volume between the first conduit 310 and the third conduit 340 have the advantage that in this additional volume a further medium can be provided. The medium can be, for instance, a liquid or gaseous medium. Preferably, the medium refers to air or nitrogen. In particular, if the medium in the additional volume refers to nitrogen, an explosion risk can be reduced.

[0076] FIGS. 6 and 7 show schematically and exemplarily an example of a ring nozzle as can advantageously be utilized, for instance, in any of the embodiments of the chemical reactor explained with respect to FIGS. 3a, 3c, 4a and 4c. In particular, the ring nozzle as shown in FIGS. 6 and 7 can be employed with respect to a reactor comprises a first conduit and a second conduit, as described above, wherein the one or more LED units are arranged in the volume between the first conduit and the second conduit. For example, in these cases the ring nozzle can be arranged at at least one end of the first and second conduit such that the ring nozzle closes the volume between the first and second conduit at this side. Preferably, a ring nozzle is provided on both ends of the first and second conduit.

[0077] FIG. 6 shows a cross section of an exemplary ring nozzle 600 in a plane perpendicular to a centreline of the conduits. The ring nozzle 600 comprises a connector arrangement 620 that allows to connect the ring nozzle to a fluid source comprising the dielectric fluid, for instance, allows to connect the ring nozzle to a fluid movement arrangement as described above. For this purpose the connector arrangement 620 can be provided with any connecting means, for instance, with a screw connection, that is configured to securely and tightly connect the ring nozzle to the fluid source. Preferably, as shown in FIG. 6 the connector arrangement is arranged tangential to a circular volume 610 of the ring nozzle. Accordingly the dielectric liquid flows tangentially into the circular volume 610. This allows for a good distribution of the dielectric liquid into the circular volume 610. Further, it is preferred that the connector arrangement 620 is configured as an injector 621 providing an acceleration to the dielectric liquid when passing the connector arrangement 620 and entering the circular volume 610. The circular volume 610 is formed by the wall of the ring nozzle 600 and comprises a plurality of openings 611 into the volume between the conduits where the LED units are arranged. This circular volume 610 is further exemplary depicted in FIG. 7 and explained below. Further, shown in FIG. 6 is a central opening 622 of the ring nozzle 600 surrounded by the circular volume 610. Preferably, the central opening 622 is dimensioned to allow an arrangement of a reactor chamber through the central opening 622. In particular, the radius of the central opening 622 has substantially the same radius as a reaction chamber configured to be arranged in the first conduit. Thus allows for an easy construction of the chemical reactor.

[0078] FIG. 7 shows a cross section 630 through the ring nozzle 600 and the conduit arrangement 640 comprising the two conduits 641 and 642. In particular, in FIG. 7 the shape of the circular volume 610 can be seen. The circular volume 610 comprises a shape that is narrower at the side of the conduits 641 and 642, i.e. the side of the plurality of openings 611, than at the opposite side. Or defined otherwise, in a cross section through the circular volume 610 along a plane parallel to a centreline of the conduits 641 and 642, the circular volume 610 comprises a substantially triangular shape. Moreover, FIG. 7 shows exemplarily the arrangement means that allow to arrange the first and second conduit 641, 642 in direct contact with the ring nozzle 600 such that the contact is impermeably for the dielectric liquid in the volume 643 between the two conduits 641, 642. In this example, the ring nozzle 600 comprise as part of the arrangement means two grooves 612 for receiving an end part of the first and second conduit 641, 642, respectively. Further, the grooves 612 comprise a notch 613 provided with an O-ring seal 614 for sealing the volume 643 between the two conduits 641, 642 and the ring nozzle 600. The O-ring seal 614 is especially suitable, since it allows to compensate for small discrepancies in the heights of the end parts of the first and second conduit 641, 642.

[0079] Preferably, the ring nozzle is adapted to be produced in a 3D printing process. For example, the ring nozzle can be made completely or partially of a printable steel or aluminium. Moreover, the ring nozzle can also be made completely or partially of printable polymer. FIG. 5 shows schematically and exemplarily a flowchart of a method 500 for transporting heat away from an LED unit, for instance, an LED unit as defined above. The method 500 comprises a first step 510 of providing a housing that is configured to house the LED unit. In particular, the housing can refer to one of the examples explained with respect to FIG. 1 to 4d. Further, in a second step 520, a dielectric liquid is provided in the housing such that it is in direct contact with at least a part of the LED unit according to the principles also described above. By moving in a last step 530 the dielectric liquid, the heat from the LED unit can be removed. The dielectric liquid can be moved, for instance, using a liquid movement arrangement in accordance with one of the above described embodiments.

[0080] Although in the above embodiments the liquid flow source and the liquid movement arrangement were together described as providing a pump in a closed circuit in which the same dielectric liquid is pumped from and to the LED unit, in other embodiments the liquid flow source and the liquid movement arrangement might not provide a closed circuit. For instance, in an embodiment, the liquid flow source and the liquid movement arrangement might be configured such that always new dielectric liquid is provided to the LED unit, wherein the dielectric liquid, after having been in contact with the LED unit, is provided to a waste reservoir by the liquid movement arrangement. Moreover, in other embodiments the same liquid flow source might be utilized for moving the dielectric liquid through a plurality of liquid movement arrangements and housings of a plurality of lighting devices. For example, the liquid movement arrangements of a plurality of lighting devices can be connected to one central liquid flow source moving the dielectric liquid through all the lighting devices.

[0081] Although in the above embodiments the lighting devices are provided outside of the reaction chamber, or such that the reaction chamber forms a part of the housing of the lighting devices, in other embodiments, the lighting devices can also be provided inside the reaction chamber. For example, a lighting device as described with respect to FIGS. 1a and 1b can simply be provided inside the reaction chamber such that the reaction medium is in direct contact with at least a part of the housing of the lighting device. Moreover, the one or more lighting devices can be attached to an inner wall of the reaction chamber.

[0082] Although in the above embodiments the housing was schematically shown to comprise a rectangular shape, a cylindrical shape, or a half cylindrical shape, also completely different housing shapes can be utilized. For example, dome shaped housings might be advantageous in applications in which the lighting device is provided inside a reaction chamber. Moreover, although in the above embodiments a plurality of LED units were provided in a lighting device with a housing comprising a half cylindrical shape, in another embodiment, instead of a plurality of LED units in one lighting device also a plurality of lighting devices comprising, for instance, a housing with a shape of a cylindrical segment and comprising only one LED unit, preferably, with a plurality of LEDs, can be utilized to provide light to a photochemical reactor provided as conduit in the middle of the lighting devices.

[0083] Although in the above embodiments all conduits have a cylindrical shape, in other embodiments the conduits can also comprise a rectangular cross section, an elliptical cross section or an arbitrarily formed cross section. Moreover, the conduits can also be bent, curved or comprise different radii along their length.

[0084] Although in the above described embodiments the centerlines of the conduits coincide and the walls are substantially parallel to each other, in other embodiments the conduits can comprise different shapes, can be arranged such that the centerlines deviate from each other or such that the walls of the conduits are not parallel to each other. In particular, the first and the third conduit can also be provided in a kind of meandering manner that is completely surrounded by the second conduit. Furthermore, more than one first conduit can be provided within the second conduit. For example, in such an embodiment a plurality of first conduits may form a plurality of different reaction chambers in which different reaction mixtures can be provided and irradiated by the lighting devices arranged within the second conduit surrounding the plurality of first conduits.

[0085] Although in the above described embodiments the dielectric liquid is described as a silicone or mineral oil, in other embodiments the dielectric liquid can be another dielectric substance comprising a respective transparency, wherein it is preferred that the dielectric liquid comprises a ignition temperature above 150° C. for applications as described above.

[0086] Other variations to the disclosed embodiments can be understood and effected by those skilled in the art in practicing the claimed invention, from a study of the drawings, the disclosure, and the appended claims.

[0087] In the claims, the word “comprising” does not exclude other elements or steps, and the indefinite article “a” or “an” does not exclude a plurality.

[0088] A single unit or device may fulfill the functions of several items recited in the claims. 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.

[0089] Any reference signs in the claims should not be construed as limiting the scope.

[0090] The invention relates to a lighting device, to the use of the lighting device in a photochemical reaction, to a photochemical reactor and to a method used by the lighting device. The lighting device comprises an LED unit configured to emit light to be used in the photochemical reaction, a housing configured to house the LED unit, wherein at least a part of the housing is transparent for light to be used in the photochemical reaction, wherein the housing is configured to contain a dielectric liquid transparent for light generated by the LED unit such that it is in direct contact with at least a part of the light emitting side of the LED unit, and a liquid movement arrangement configured to support a movement of the dielectric liquid such that the dielectric liquid transports heat produced by the LED unit away from the LED unit.