AIR TREATMENT UNIT AND METHOD FOR TREATMENT OF AIR

Abstract

An air treatment unit (100) arranged for an intake of a first flow (110) of air into a space (120) in communication with the air treatment unit, and arranged for a discharge of a second flow (130) of air from the space. The air treatment unit comprises a heat-exchanging unit (140) arranged for thermal exchange between the second flow of air and the first flow of air, and a catalyst (150) configured to capture at least one impurity of the first flow of air. The catalyst is provided on at least a portion (160) of the heat-exchanging unit arranged to come into contact with the first flow of air during operation of the air treatment unit.

Claims

1.-16. (canceled)

17. An air treatment unit arranged for an intake of a first flow of air into a space in communication with the air treatment unit, and arranged for a discharge of a second flow of air from the space, the air treatment unit comprising: a heat-exchanging unit arranged for thermal exchange between the second flow of air and the first flow of air, and a catalyst configured to capture at least one impurity of at least one of the first flow of air and the second flow of air, wherein the catalyst is provided on at least a portion of the heat-exchanging unit arranged to come into contact with at least one of the first flow and the second flow of air during operation of the air treatment unit, wherein the catalyst comprises from 1-50 weight-%, based on the total weight of the catalyst, of a noble metal selected from the group consisting of platinum, palladium, gold, silver, and rhodium, which has been dispersed on from 50-99 weight-%, based on the total weight of the catalyst, of a metal oxide which possesses more than one stable oxidation state including at least tin oxide, and wherein the first flow of air is ambient outdoor air.

18. The air treatment unit of claim 17, wherein the catalyst comprises a coating provided on the at least a portion of the heat-exchanging unit.

19. The air treatment unit of claim 17, wherein the catalyst comprises an immersion coating arranged for coating the at least a portion of the heat-exchanging unit by immersion of the at least a portion of the heat-exchanging unit into the immersion coating.

20. The air treatment unit of claim 17, wherein the catalyst comprises a spray provided on the at least a portion of the heat-exchanging unit.

21. The air treatment unit of claim 17, wherein the heat-exchanging unit comprises an element which upon rotation is arranged to come into contact with the second flow of air and the first flow of air for thermal exchange between the second flow of air and the first flow of air, and wherein the catalyst is provided on at least a portion of the element.

22. The air treatment unit of claim 21, wherein the element is shaped as a disc, and wherein the catalyst is provided on at least a portion of at least one of the sides of the disc.

23. The air treatment unit of claim 21, wherein the element is shaped as a disc of concentrically arranged layers, and wherein the catalyst is provided on at least a portion of an edge of at least one of the layers of the element.

24. The air treatment unit of claim 17, wherein the heat-exchanging unit comprises at least one tube for guiding at least one of the first flow of air and the second flow of air, wherein the catalyst is provided on at least a portion of the inside of the at least one tube.

25. The air treatment unit of claim 17, wherein the heat-exchanging unit comprises at least one first passage for guiding the first flow, at least one second passage for guiding the second flow, and at least one plate arranged to separate the at least one first passage and the at least one second passage and arranged for thermal exchange between the second flow of air and the first flow of air, wherein the catalyst is provided on at least a portion of the at least one plate.

26. The air treatment unit of claim 17, wherein the heat-exchanging unit comprises at least one material selected from the group consisting of aluminum, copper, and zinc.

27. An air handling system comprising: an air treatment unit arranged for an intake of a first flow of air into a space in communication with the air treatment unit, and arranged for a discharge of a second flow of air from the space, the air treatment unit comprising: a heat-exchanging unit arranged for thermal exchange between the second flow of air and the first flow of air, and a catalyst configured to capture at least one impurity of at least one of the first flow of air and the second flow of air, wherein the catalyst is provided on at least a portion of the heat-exchanging unit arranged to come into contact with at least one of the first flow and the second flow of air during operation of the air treatment unit, wherein the catalyst comprises from 1-50 weight-%, based on the total weight of the catalyst, of a noble metal selected from the group consisting of platinum, palladium, gold, silver, and rhodium, which has been dispersed on from 50-99 weight-%, based on the total weight of the catalyst, of a metal oxide which possesses more than one stable oxidation state including at least tin oxide, and wherein the first flow of air is ambient outdoor air, p1 an inlet arranged for an intake of a first flow of air into a space of the air handling system, wherein the inlet is in communication with the space via the air treatment unit, and an outlet arranged for a discharge of a second flow of air from the space, wherein the space is in communication with the outlet via the air treatment unit.

28. The air handling system of claim 27, wherein the air handling system further comprises at least one filter arranged for filtering at least one of the first flow of air and the second flow of air, wherein the catalyst is provided on at least a portion of the at least one filter.

29. The air handling system of claim 27, wherein the air handling arrangement further comprises at least one fan arranged for generating at least one of the first flow of air and the second flow of air, wherein the catalyst is provided on at least a portion of the at least one fan.

30. A method for treatment of air by an air treatment unit arranged for an intake of a first flow of air into a space in communication with the air treatment unit, and arranged for a discharge of a second flow of air from the space, wherein the air treatment unit comprises a heat-exchanging unit arranged for thermal exchange between the second flow of air and the first flow of air, the method comprising the steps of: providing a thermal exchange between the second flow of air and the first flow of air by the heat-exchanging unit, providing a catalyst on at least a portion of the heat-exchanging unit, wherein the catalyst is configured to capture at least one impurity of at least one of the first flow of air and the second flow of air, and wherein the catalyst comprises from 1-50 weight-%, based on the total weight of the catalyst, of a noble metal selected from the group consisting of platinum, palladium, gold, silver, and rhodium, which has been dispersed on from 50-99 weight-%, based on the total weight of the catalyst, of a metal oxide which possesses more than one stable oxidation state including at least tin oxide, and guiding at least one of the first flow of air and the second flow of air to come into contact with the at least one portion of the heat-exchanging unit, wherein the first flow of air is ambient outdoor air.

31. The method of claim 30, wherein the step of providing the catalyst comprises coating the at least one portion of the heat-exchanging unit with the catalyst.

32. The method of claim 30, wherein the step of providing the catalyst comprises spraying the at least one portion of the heat-exchanging unit with the catalyst.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0044] This and other aspects of the present invention will now be described in more detail, with reference to the appended drawings showing embodiment(s) of the invention.

[0045] FIG. 1 is a schematic view of a system for the treatment of air according to the prior art,

[0046] FIG. 2 is a schematic view in cross-section of an air treatment unit according to an exemplifying embodiment of the present invention,

[0047] FIGS. 3-5 are schematic views of portions of a heat-exchanging unit of an air treatment unit according to an exemplifying embodiment of the present invention.

[0048] FIG. 6 is a schematic view of an air handling system according to exemplifying embodiment of the present invention, and

[0049] FIGS. 7-8 are schematic views of catalysts according to exemplifying embodiments of the present invention.

DETAILED DESCRIPTION

[0050] FIG. 1 shows a system 10 for the treatment of air according to the prior art. The system 10 utilizes a combination of adsorption and catalytic or thermal technologies to concentrate volatile organic compounds (VOCs) for destruction in a catalytic or thermal oxidizer. A main air flow 20 passes through a concentrator wheel 30 of the system 10 for a concentration of the VOCs. At the same time, a second air flow 40 is passed through the concentrator wheel 30 in the opposite direction. The second air flow 40 desorbs the VOCs from the concentrator wheel 30 and the VOCs are destroyed in a catalytic or thermal oxidizer 50. The system 10 comprising a concentrator wheel 30 of this kind may be useful for VOC concentrations that are too high for a cost-effective use of sacrificial systems and too low for a cost-effective use of thermal or catalytic oxidisers. However, systems of this kind according to the prior art are associated with numerous problems and/or deficiencies. First, these systems are usually bulky, and are often too large to be fit into and/or connected to commercial and residential air handling units (AHUs). Second, the prior art systems are associated with a relatively high costs. Furthermore, during an operation of systems of this kind, the VOC concentrator wheel 30 may require frequent refurbishments of the thermal oxidizer (depending on the VOC concentration to be concentrated) and a heating of the air for the thermal oxidizer to desorb the VOCs. Moreover, since the VOC concentrator wheel 30 may comprise zeolite or regenerable carbon, the system may experience a considerable pressure drop. Consequently, the flow rates of fans in the system 10 need to be increased, leading to an increase of the overall energy consumption of the system 10. Furthermore, the cleaning of exhaust air, which is required for systems of this kind, requires a relatively large piping construction. Apart from an increasing cost associated with this, the construction may increase the system complexity and volume, which is especially problematic in case the space is limited.

[0051] FIG. 2 is a schematic view in cross-section of an air treatment unit 100 according to an exemplifying embodiment of the present invention. The air treatment unit 100 comprises an inlet 105, e.g. in the form of a first tubing, for the intake and guiding of a first flow 110 of air. It will be appreciated that the air of the first flow 110 of air may be ambient, outdoor air. The first flow 110 of air may be further distributed by the air treatment unit 100 into a space 120 which is in (fluid) communication with the air treatment unit 100. The space 120 may, for example, be a room, building, office, or the like. The air treatment unit 100 is further in (fluid) communication with the space 120 and arranged for a discharge and guiding of a second flow 130 of air from the space 120 via an outlet 115, e.g. in the form of a second tubing, of the air treatment unit 100. The air treatment unit 100 further comprises a heat-exchanging unit 140 which is arranged for thermal exchange between the second flow 130 of air and the first flow 110 of air. It will be appreciated that the heat-exchanging unit 140 may be of substantially of any type suitable for thermal exchange between the second flow 130 of air and the first flow 110 of air. For example, the heat-exchanging unit 140 may be of a so called rotary heat exchanger type, a shell and tube heat exchanger type or a plate heat exchanger type.

[0052] The air treatment unit 100 further comprises a catalyst 150 which is configured to capture, adsorb and/or absorb, and to convert, at least one impurity of the first flow 110 of air and/or the second flow 130 of air. More specifically, the catalyst 150 may capture, adsorb and/or adsorb the impurity/impurities of the first flow 110 of air and/or the second flow 130 of air, enable a reaction between the impurity/impurities and an oxidizing agent, and desorb the oxidation products, thereby freeing sites for subsequent absorptions and reactions. Hence, the catalyst 150 may capture one or more impurities such as benzene, nitrogen oxide (NO.sub.x), sulphur dioxide, carbon monoxide, benzo(a)pyrene, radon, ozone, etc., and convert (oxidize) one or more of these impurities into non-toxic components such as CO.sub.2, H.sub.2O, etc. The catalyst 150 may be particularly suitable, configured and/or adapted for capturing or absorbing volatile organic compounds (VOC) e.g. including hydrocarbons (HC), formaldehyde, alcohols, etc., and convert (oxidize) one or more of these impurities.

[0053] The catalyst 150 of the air treatment unit 100 may comprise or constitute (platinum coated) tin dioxide (SaO.sub.2). For example, the weight percent of the platinum in platinum coated tin dioxide may be in the range of 3-20%. Particles of platinum-coated SnO.sub.2 may be fabricated in a size-range that is comparable to the pigments of paint products that can be brushed or sprayed onto portion(s) of the heat-exchanging unit 140. For example, the particles may have diameters in the order of 10 μm or less.

[0054] Alternatively, the catalyst 150 of the air treatment unit 100 may comprise at least two precious metals with at least two different metal-oxides (for example, tin oxide plus one or more promoters) in a layered matrix. Precious metals can together comprise about 0.1-15 weight-% of the catalyst 150. The at least one promoter metal oxide may be chosen from metal oxide species from the transition series of the periodic table which are known to adsorb NO.sub.x species, namely, Fe.sub.2O.sub.3, NiO, Co.sub.2O.sub.3 and WO.sub.3. The composition of the promoter oxide(s) can vary from about 1-15 weight-% of the total catalyst 150 material. Specifically, about 10 weight-% of the catalyst may be Fe.sub.2O, NiO, Co—O, combined with about 1.25 weight-% of the catalyst 150 being platinum and ruthenium, with the balance being tin oxide. For example, the catalyst 150 may comprise 70-99 weight-% of a metal oxide possessing more than one oxidation state (e.g. tin oxide), 0.1-15 weight-% of at least two precious metals of which one is Ru and the other is chosen from the group consisting of platinum (Pt), palladium (Pd), gold (Au), rhodium (Rh) and silver (Ag). The catalyst 150 may further comprise 1-15 weight-% of at least one promoter selected from the group consisting of Fe.sub.2O.sub.3, NiO, Co.sub.2O.sub.3 and WO.sub.3. It will be appreciated that the catalyst 150 as exemplified is associated with numerous advantages. For example, the relatively low light-off temperatures for CO and HC may enable an even more efficient catalytic conversion to CO.sub.2 at a lower cost. The precious metal coatings may be applied to the top surface of the catalyst 150 and are enabled to be more efficiently used. Consequently, less precious metals may be required resulting in lower costs. Moreover, the mixed precious metals may result in a more efficient oxidation/reduction catalyst 150 and may be applied in one step.

[0055] As yet another alternative, the catalyst 150 of the air treatment unit 100 may comprise 1-50 weight-% of a noble metal selected from the group consisiting of platinum (Pt), palladium (Pd), gold (Au), rhodium (Rh) and silver (Ag). The noble metal may have been dispersed on from about 50-99 weight-% of a metal oxide which possesses more than one stable oxidation state including at least tin oxide. The preparation of such a platinum-tin oxide-based catalyst 150 may be accomplished by successive layering of the desired components, as follows: (1) a clean, dry substrate may be deaerated in a solution containing tin (H) 2-ethylhexanoate (SnEH, hereafter). The substrate is removed from the solution, and excess solution is removed from the substrate. Residual solution components are evaporated leaving an SnEH layer on the substrate which is thermally decomposed in air to tin oxide at 300° C. Several layers may be applied in the same manner to achieve the desired loading of tin oxide. (2) If desired, a promoter is added to the catalyst matrix in a similar fashion. For example, an iron oxide promoter may be added to an existing tin oxide-coated substrate by dearating in an iron nitrate solution, removing excess solution, evaporating the solvent, and finally thermally decomposing the nitrate to oxide, (3) Platinum may be added to the coated, substrate as above using an aqueous solution of tetraamine platinum (II) dihydroxide or other platinum salt, with chloride-fee salts being preferred, and then thermally decomposing the salt. Instead of the thermal decomposition, a reductive decomposition can be used. For example, the catalyst coated substrate is heated in an atmosphere containing a reducing gas such as carbon monoxide or hydrogen to induce reduction of the platinum salt to platinum.

[0056] The active temperature of the catalyst 150 of the air handling unit 100 may be −10° C.-500° C. For example, for conversion of formaldehyde (CH.sub.2O), the temperature of the catalyst 150 may be 0° C.-25° C., or even somewhat lower. For hydrocarbons (HC), desorption may take place from an initial temperature of the catalyst 150 of about 35° C., and oxidation may be performed at an active temperature of the catalyst 150 at 80° C.-120° C. The light-off temperature may be about 150° C. for hexane (C.sub.6H.sub.14) and about 220° C. for methane (CHS). A complete oxidation may occur at an active temperature of the catalyst 150 well below the autoignition temperature of each hydrocarbon, e.g. 309° C. for pentane (C.sub.5H.sub.12) and 537° C. for methane. As yet another example, the temperature of the catalyst 150 for oxidation of ethanol (C.sub.2H.sub.5OH) may be about 30° C., and complete oxidization may be achieved at 125° C. Analogously, for propanol (C.sub.3H.sub.7OH), the respective temperatures of the catalyst may be 50° C. and 120° C. For the oxidation of carbon monoxide (CO) and the reduction of nitrogen oxides (NO.sub.x), the active temperature of the catalyst 150 may be 200° C. -500° C. The catalyst 150 is provided on at least a portion 160 of the heat-exchanging unit 140, which portion(s) 160 is (are) arranged to come into contact with the first flow 110 of air and/or the second flow 130 of air during operation of the air treatment unit 100. It will be appreciated that the arrangement of the catalyst portion 150 on the portion(s) 160 of the heat-exchanging unit 140, as well as the portion(s) 160 itself, are schematically indicated for an increased understanding of the concept of the present invention. In other words, the portion 160 of the heat-exchanging unit 140 of the air treatment unit 100 is schematically shown for illustrative purposes only, and it should be noted that the portion(s) 160 may take on substantially any form on and/or of the heat-exchanging unit 140 of the air treatment unit 100.

[0057] FIG. 3a is a schematic view of a portion of a heat-exchanging unit 140 of an air treatment unit 100 according to an exemplifying embodiment of the present invention. In this example, the heat-exchanging unit 140 is of a so called rotary heat exchanger type, and comprises a disc-shaped element 500 which is configured to rotate upon operation of the heat-exchanging unit 140. More specifically, the element 500 is arranged to come into contact with the second flow 130 of air and the first flow 110 of air upon rotation of the element 500, for thermal exchange between the second flow 130 of air and the first flow 110 of air. The catalyst 150 is provided on at least one of the sides 610a, 610h of the element 500 for capturing at least one impurity of the first flow 110 of air and/or the second flow 130 of air. FIG. 3b is a schematic view of a portion of a heat-exchanging unit 140 of an air treatment unit 100 according to an exemplifying embodiment of the present invention. Analogously with the example of FIG. 3a, the heat-exchanging unit 140 is of a so called rotary heat exchanger type. The heat-exchanging unit 140 comprises a disc-shaped element 500 which is configured to rotate upon operation of the heat-exchanging unit 140 and is arranged to come into contact with the second flow 130 of air and the first flow 110 of air upon rotation of the element 500. The element 500 is shaped as a disc of concentrically arranged layers 710. and the catalyst 150 is provided on at least a portion of an edge 720 of at least one of the layers of the element 500 for capturing at least one impurity of the first flow 110 of air and/or the second flow 130 of air.

[0058] It should be noted that a combination of the examples of FIG. 3a and FIG. 3b is also feasible. More specifically, the catalyst 150 may be provided on at least one of the sides 610a, 610b of the element 500, as shown in FIG. 3a, as well as on the on at least a portion of an edge 720 of at least one of the layers of the element 500, as shown in FIG. 3b.

[0059] FIG. 4 is a schematic view of a portion of a heat-exchanging unit 140 of an air treatment unit according to an exemplifying embodiment of the present invention The heat-exchanging unit comprises at least one first tube or tubing 800a for guiding the first flow 110 of air into a space (not shown), and at least one second tube or tubing 800a for discharging and guiding the second flow 130 of air away from the space. The first tube(s) or tubing(s) 800a and the second tube(s) or tubing(s) 800a are arranged adjacently and are in thermal connection. The second flow 130 of air is arranged to flow through the second tube(s) or tubing(s) 800b to transfer heat between the second flow 130 of air and the first flow 110 of air arranged to flow through the first tube(s) or tubing(s) 800a. The catalyst 150 of the air treatment unit is provided on at least a portion of the inside of the first tube(s) or tubing(s) 800a and/or the second tube(s) or tubing(s) 800b for capturing at least one impurity of the first flow 110 of air and the second flow 130 of air. It will be appreciated that the catalyst 150 may be arranged on different portion(s) than those indicated in FIG. 4, which is provided for an illustrative purpose only. Furthermore, it should be noted that the first tube(s) or tubing(s) 800a and/or the second tube(s) or tubing(s) 800b of the heat-exchanging unit 140 may be arranged differently than disclosed in FIG. 4.

[0060] FIG. 5 is another schematic view of a portion of a heat-exchanging unit 140 of an air treatment unit according to an exemplifying embodiment of the present invention. The heal-exchanging unit 140 comprises at least one first passage 910 for guiding the first flow 110 of air. Analogously, the heat-exchanging unit 140 comprises at least one second passage 920 for guiding the second flow 130 of air. The heat-exchanging unit 140 further comprises at least one plate 930 arranged to separate the first passage(s) 910 and the second passage(s) 920. The plate(s) 930 is (are) arranged for a thermal exchange between the second flow 130 of air and the first flow 110 of air. The catalyst 150 of the air treatment unit is provided on at least a portion of the plate(s) 930 for capturing impurities of the first flow 110 of air and/or the second flow 130 of air. It will be appreciated that the catalyst 150 may be arranged on different portion(s) of the plate(s) 930 and/or on different plate(s) 930 than that (those) indicated in FIG. 5, which is provided for an illustrative purpose only.

[0061] FIG. 6 is a schematic view of an air handling system 1000 according to an exemplifying embodiment of the present invention. The air handling system 1000 comprises an air treatment unit 100 as exemplified in FIG. 2. The air handling system 1000 further comprises an inlet 105 arranged for an intake of a first flow 110 of air into a space 120 of the air handling system 1000. The inlet 105, which is exemplified as a tubing, is in communication with the space 120 via the air treatment unit 100. The air handling system 1000 further comprises an outlet 115, exemplified as a tubing, which is arranged for a discharge of a second flow 130 of air from the space 120. The space 120 is in communication with the outlet 115 via the air treatment unit 100. The air treatment unit 100 comprises a heat-exchanging unit 140 which is arranged for thermal exchange between the second flow 130 of air and the first flow 110 of air as described according to one or more of the previous embodiments. The air treatment unit 100 further comprises a catalyst 150 which is configured to capture at least one impurity of the first flow 110 of air and/or the second flow 130 of air. The catalyst 150 is provided on at least a portion 160 of the heat-exchanging unit 140, which portion(s) is (are) arranged to come into contact with the first flow 110 of air and/or the second flow 130 of air during operation of the air treatment unit 100 of the air handling system 1000. Similar to FIG. 2, it will be appreciated that the arrangement of the catalyst portion 150 on the portion(s) 160 of the heat-exchanging unit 140, as well as the porn on(s) 160 itself, are schematically indicated for an increased understanding of the concept of the present invention.

[0062] The air handling system 1000 in FIG. 6 further comprises a first filter 1110a arranged in the inlet 105 and upstream of the air treatment unit 100 in the direction of the first flow 110 of air. The first filter 1110a is arranged for filtering the first flow 110 of air before entering the space 120 of the air handling system 1000. The air handling system 1000 further comprises a second filter 1110b arranged in the outlet 115 and upstream of the air treatment unit 100 in the direction of the second flow 130 of air, for filtering the second flow 130 of air. The first filter 1110a and/or the second filter 1110b may, for example, constitute one or more coarse filters for filtering debris of the air, such as leaves, relatively large particles, dust, pollen, etc. The catalyst 150 of the air treatment unit 100 of the air handling system 1000 may be provided on at least a portion of the first filter 1110a and/or the second filter 1110b for capturing impurities of the first flow 110 of air and/or the second flow 130 of air.

[0063] The air handling system 1000 further comprises a first fan 1210a arranged for generating the first flow 110 of air towards the space 120 of the air handling system 1000, The first fan 1210a is arranged in the inlet 105 and downstream of the air treatment unit 100 in the direction of the first flow 110 of air. Analogously, the air handling system 1000 further comprises a second fan 1210b arranged for generating the second flow 130 of air from the space 120 of the air handling system 1000. The second fan 1210b is arranged in the outlet 105 and downstream of the air treatment unit 100 in the direction of the second flow 110 of air, The catalyst 150 of the air treatment unit 100 of the air handling system 1000 may be provided on at least a portion of the first fan 1210a and/or the second fan 1210b for capturing impurities of the first flow 110 of air and/or the second flow 130 of air arranged to pass the first fan 1210a and/or the second fan 1210b.

[0064] FIG. 7a is a schematic view of a catalyst coating 200 according to an exemplifying embodiment of the present invention. A portion 160 of the heat-exchanging unit of the air treatment unit is schematically shown for illustrative purposes only, and it should be noted that the portion 160 may take on substantially any form and/or be part of one or more elements and/or units of the air treatment unit. For example, the portion 160 may be a portion 160 of a heat-exchanging unit, a filter, a fan, a passage, a duct, a tubing, or the like, according to one or more of the above-mentioned examples. The catalyst 150 comprises a coating 200 provided on the portion 160. Wherein the coating 200 is arranged for capturing impurities of an air flow. FIG. 7b schematically shows the provision of the catalyst on the portion 160 according to a method of the present invention. Here, the method comprises an immersion coating 300 of the portion 160, i.e. immersion or dipping of the portion 160 into a solution of the catalyst.

[0065] FIG. 8a is a schematic view of a provision of a catalyst 150 on a portion 160 of a heat-exchanging unit according to an exemplifying embodiment of the present invention. Analogously with FIG. 7a, the portion 160 of the heat-exchanging unit of the air treatment unit is schematically shown for illustrative purposes only, and it should be noted that the portion may take on substantially any form. Here, the catalyst 150 is provided in the form of a spray 400 (i.e. liquid particles) on the portion 160, wherein the catalyst 150 is arranged for capturing impurities of an air flow. The catalyst 150 may be dispersed in a porous sol-gel binder, and be applied in the form of a spray 400 while the sol-gel binder is in its solution state. FIG. 8b schematically shows the associated provision of the catalyst 150 on the portion 160 of a heat-exchanging unit according to a method of the present invention. Here, the catalyst 150 is sprayed on the portion 160 of the heat exchanging unit, such that the spray 400 of liquid particles are provided on the portion 160.

[0066] The person skilled in the art realizes that the present invention by no means is limited to the preferred embodiments described above. On the contrary, many modifications and variations are possible within the scope of the appended claims. For example, it will be appreciated that the figures are merely schematic views of printer units according to embodiments of the present invention. Hence, any elements/components of the air treatment unit 100 and/or the air treatment system 1000 such as the heat exchanging unit 140, the inlet 105, the outlet 115, the first filter 1110a, the second filter 1110b, the first fan 1210a, the second fan 1210b, etc., may have different dimensions, shapes and/or sizes than those depicted and/or described.