Air handling unit with housing for biocontrol of microbial infections

Abstract

The present invention relates to a supply-exhaust air handling unit, equipped with a housing, a counter-current heat exchanger, a fans, an exhaust air filters, a preheater, a bypass system and a control system, wherein the housing (1) consists of two fittings (1a, 1b) formed by injection method from foamed polypropylene, which are permanently joined together by means of gluing, wherein the inner surface of the fittings (1a, 1b) is covered with a coating (2) having antistatic, antibacterial and antifungal properties, wherein the housing (1) being at the same time a supporting structure to which the other elements of the equipment of the air handling unit are mounted.

Description

[0001] An object of the invention is an air handling unit for ventilation systems, especially for living and office spaces. More specifically, an object of the invention is an air handling unit whose body comprises a composition for biocontrol of microbial infections.

[0002] Commercially available air handling unit constructions are made of a metal frame to which the individual components of the unit are mounted or, for units made of foamed materials, are fitted with additional stiffening elements. This results in a high weight of the unit, the assembly of which often requires several workers, and at the same time increases the consumption of materials for production.

[0003] It has been noted that people who stay in a building for a long period of time can develop a syndrome of health complaints called sick building syndrome known as SBS, manifested, for example, by headaches and dizziness, fainting, symptoms of fatigue or irritation of the mucous membranes. SBS is caused by insufficient fresh air and / or poor air quality.

[0004] The available at the state of the art solutions to this problem focus on improving the ventilation capacity to ensure sufficient fresh air supply or on equipping the air handling unit with air filters to reduce inlet air pollutants such as particulate matter and / or volatile organic compounds.

[0005] However, this does not solve the problem of SBS, as micro-organisms can develop in the ventilation ducts and in the air handling unit due to the contact of these surfaces with moist air, which are introduced with the air current into the ventilated rooms.

[0006] In the state of the art, solutions to the problem of reducing the growth of microorganisms are available by providing compositions with antibacterial activity.

[0007] European patent application EP0972806A1 discloses a composition comprising a non-halogenated thermoplastic resin and bamboo powder in an amount of 20 to 80% by weight, which has an antibacterial effect. Articles such as an air conditioner fan, parts of the air purification chamber of the composition can be produced from the said composition by a thermoforming method. Unfortunately, this solution requires the use of bamboo powder with a low water content, with a certain fibre size, which must be subjected to additional treatment, as otherwise a strong burning smell is released during injection moulding and contamination of the mould occurs.

[0008] In the opinion of the inventors of the present invention, the invention EP0972806A1 does not provide data on mechanical resistance and resistance to variable temperatures for the structural components of an air conditioner made from the composition according to the invention. Therefore, there is a concern that such components may degrading over time and releasing resin particles and released bamboo powder into the environment, also into ventilated rooms.

[0009] Solution disclosed at the present invention have solved the technical problems presented in an alternative way.

[0010] An object of the present invention is to propose a lightweight air handling unit with a durable coating to reduce the occurrence of SBS syndrome.

[0011] The present invention provides a supply / exhaust air handling unit, having a housing, a counter-current flow heat exchanger, fans, an intake air filter, an exhaust air filter, a pre-heater, a bypass system and a control system, characterized in that the housing consist of two injection moulded fittings from foamed polypropylene which are permanently bonded to each other by adhesion, wherein an inner surface of the fittings is coated with a coating with antistatic, anti-bacterial, and anti-fungal properties, and the housing is at the same time a supporting structure to which the remaining equipment is mounted.

[0012] In the supply / exhaust air handling unit, also called air handling unit, according to the invention, the coating consist of a substrate-adhesion enhancing primer consisting of a 20% xylene-dispersed chlorinated polyolefin solution layer and a base layer consisting of at least one layer of a composition based on a two-component polyurethane solvent paint having a weight ratio of component A to B of 100:63, the quantitative and qualitative composition of components A and B being set forth in Table 1.

[0013] In the course of research and development it was found that for a substrate made of foamed polypropylene, known as expanded polypropylene EPP, the proper adhesion of the coating to the substrate was obtained by applying the primer in the form of a 20% 20% xylene-dispersed chlorinated polyolefin solution, known under the trade name Trapylen ®< 112X, which is an adhesion promoter.

[0014] In the solution according to the invention, the provision of supply / exhaust air handling unit which is durable and non-erosive during operation is very important, since the inner surface of the coated fittings is in contact with the air expelled from the rooms and supplied to the rooms. In the solution according to the invention there is no risk of introducing micro-contaminants from peeling fragments of the coating into the ventilated rooms. Tests according to PN-C / 89258-1:1997 (published 1997-05-21) have shown adhesion of the coating at the level of 2 N / 25 mm to 5 N / 25 mm.

[0015] In addition, in the solution according to the invention, the coating exhibits antibacterial activity after 6 months of aging for the strains of Escherichia coli (ATCC 8739) and Staphyloccocus aureus (ATCC 6538 P), 2. 9 and 2. 0, respectively, as determined according to ISO 22196:2011 (date of publication 2011-08).

[0016] In addition, in the solution according to the invention, the coating exhibits antifungal activity after 6 months of aging for strains of Aspergillus niger (ATCC 6275), Penicillium pinophilum (ATCC 36839), Paecilomyces variotli (ATCC 18502), Trichoderma virens (ATCC 9645), Chaetomium globosum (ATCC 6205), on a visual assessment of 0 / 1 level and on a microscopic assessment of 0 as determined by PN-ISO 846:2019 (date of publication 2019-05-10).

[0017] The air handling unit according to the invention is suitable for use in ventilation systems designed especially for servicing residential buildings and offices. Thanks to its concise and compact design and at the same time its rigidity, the air handling unit is suitable for mounting on mounting feet, on the wall using mounting pins or brackets and under the ceiling using mounting pins.

[0018] In turn, the low weight of the body constituting the housing of the air handling unit makes the weight of the whole device considerably lower and it can be assembled by one person.

[0019] In addition, thanks to making the housing of the air handling unit from EPP, the body simultaneously fulfils the function of thermal insulation, lowering the risk of water vapour condensation on the housing of the device.

[0020] The object of the invention is illustrated on the figures of the drawing, in which: Fig.1 presents the construction of the air handling unit body in an isometrics view, Figure 2 presents the air handling unit together with the equipment in an isometric view.

[0021] In the following detailed embodiment of the invention, a configuration of the air handling unit adapted to some standard elements of the unit equipment is shown. However, it is understood by those skilled in the art that the configuration of the body of the air handling unit according to the invention will always correspond to the dimensions of the equipment elements and does not affect the essence of the solution.

[0022] The elements of the exemplary body of the air handling unit forming the housing are two injection moulded fittings made of EPP, a material resistant to damage or fracture. In addition, EPP can be recycled, so the ventilation units of the invention reduce the carbon footprint in the environment. At the same time, the fittings, formed the housing of the air control unit, are joined together in a known manner, especially by means of gluing, which means that the housing does not need to be additionally sealed.

[0023] An exemplary air handling unit is equipped with a counter-current heat exchanger (3), fans (5,6), an intake air filters (7,8), an exhaust air filter (9), a preheater (4), a control system (10) and a bypass system (11).

[0024] After the body fittings (1a and 1b) have been formed from EPP, a layer of a 20% xylene-dispersed chlorinated polyolefin solution is first applied to their inner surfaces as a primer to improve adhesion to the EPP substrate, and then, after drying for about 30-40 minutes, the base layer is applied as a single layer of a composition based on a two-component polyurethane solvent paint having a weight ratio of components A to B of 100:63. The base layer, after drying, has a thickness of at least 40 micrometres.

[0025] The composition of the polyurethane solvent-based paint composition is shown in Table 1. Table 1 Composition of the polyurethane solvent-based paint compositionL.p.MaterialManufacturerNamekg / 1000 kgComponent A (100) 1Setal 168 SS-80AllnexLow branched polyester polyol with 4,3% OH290,002Disperbyk 163Byk ChemieSolution of modified polyurethane15,343BYK 354Byk ChemiePolyacrylate solution1,804BYK 410Byk ChemieModified urea solution5,005Carbon black Printex XE 2BOrion Engineered CarbonsTechnical carbon black (formless)6,586Carbon black Printex UOrion Engineered CarbonsTechnical carbon black (formless)14,517Microtalc M-15ElementisMicronised talc40,908Acematt TS-100Evonik Industries AGQuartz14,909XyleneBrenntagXylene46,4710Ethyl acetateBrenntagEthyl acetate261,3411Butyl acetateBrenntagButyl acetate185,9012Methoxypropyl acetate (PMA)BrenntagMethoxypropyl acetate (PMA)67,6313Wacker Silicone Fluid L053BrenntagPolysiloxane with functional groups + polyglycoether0,2114Kosmos 19Evonikdibutyl tin dilaurate0,7615Nanosilver Polsilver 50ANoweko sp. z o.o.Nanosilver13,9516Preventol MP 700LANXESSIodopropinyl butyl carbamate solution34,82Skfadnik B (63) 17Desmodur HLBACovestro AGAromatic / aliphatic polyisocyanate based 2,4-Toluene diisocyanate (TDI) / hexamethylene diisocyanate (HDI).500,0018Ethyl acetateBrenntagEthyl acetate500,00

[0026] The antibacterial activity and fungostatic tests were carried out and the adhesion of the coating (3) to the EPP substrate was examined. The fitting (1a, 1b) which inner side thereof is coated with a single layer of the primer and with a single layer of polyurethane solvent-based paint composition, directly upon their application and drying, is hereinafter referred to as a sample.a. Antibacterial properties

[0027] Tests were carried out in accordance with ISO 22196:2011 for reference strains of Escherichia coli (ATCC 8739) and Staphyloccocus aureus (ATCC 6538 P).

[0028] Sample after production, showed antibacterial activity for E. coli: R = 2,2 for S. aureus: R = 2,2

[0029] Sample aged (6 months), showed antibacterial activity for E. coli: R = 2,9 for S. aureus: R = 2,0 b. Fungostatic properties

[0030] Fungostatic properties were verified according to EN ISO 846:2019 for Aspergillus niger (ATCC 6275), Penicillium pinophilum (ATCC 36839), Paecilomyces variotli (ATCC 18502), Trichoderma virens (ATCC 9645), Chaetomium globosum (ATCC 6205) strains. The result of visual evaluation in accordance with PN-EN ISO 846:2019: sample after production: 2 sample after ageing (6 months): 0 / 1

[0031] Result of microscopic evaluation according to PN-EN ISO 846:2019: sample after ageing (6 months): 0

[0032] A contact test was also carried out using a PCA LAB-AGAR ®< substrate (supplier of BioMaxima) having the composition: casein peptone 5,00 g / I yeast extract 2,50 g / I glucose 1,00 g / I agar 15,00 g / l

[0033] Contact studies (Rodak test) were performed on samples after 7 days of acclimatization and 4 months of aging. For this purpose, PCA LAB AGAR ®< substrate plates were applied to the inner surface of the sample for 10 seconds, which were then sealed and labelled. The plates were incubated horizontally, with the lid upwards for 48 h, without access to light. After this time, the grown colonies were counted in an area of 25 cm 2< .

[0034] For both the sample after acclimatization and after 4 months of aging, the result was <1 cfu / cm2, indicating the high microbiological purity of the samples.c. Coating adhesion test

[0035] The adhesion of the coating was tested according to PN-C / 89258-1:1997 using a 12 mm wide strip and linear adhesion to steel ranging from 2 N / 25 mm to 5 N / 25 mm. For this purpose, tape was applied to the centre of the inner surface of the samples and pressed evenly with a finger for 3 seconds. The tape was then torn off by rapid motion at an angle of about 150°. The coating was visually assessed as adhesive / non-adhesive. To determine the correct adhesion in the visual assessment, the focus of the imprint should not change, and the coating should not pass onto the tape.

[0036] Visual evaluation result: print sharpness did not change, no coating fragments were found on the tape.

[0037] Result: The tape does not tear off the coating.

[0038] The coefficient of friction, expressed as the stripping force of the strip according to PN-EN ISO 8295, was also tested. The result was 5. 36 N.

[0039] The goniometric measurement of the surface energy of the substrate was also carried out.

[0040] The following results were obtained: water wetting angle: 85. 19° diiodomethane wetting angle: 67,40° substrate surface energy: 29,62 mN / m

[0041] Summary: Applying a durable coating to elements made of EPP is a technological difficulty due to the properties of the material. The solution according to the invention provides a coating which is permanently bonded to the substrate and exhibits tear resistance.d. Comparative mass test

[0042] There is no standardised indicator to compare the mass of a similar class of equipment.

[0043] Therefore, for the purpose of quantitative comparison of the solution according to the invention with competing solutions, a coefficient, hereinafter referred to as the mass factor, is introduced. This mass factor linking the maximum capacity of the apparatus ( also defined as the maximum volumetric flow of air exchanged by the apparatus) and the mass of the apparatus by the quotient of these values. An analysis was made taking into account 88 competing devices for which the mass factor was calculated, which ranged from 2. 8 m 3< h -1< kg -1< to 16. 8 m 3< h -1< kg -1< (Table 2). Table 2. Mass factor analysis for different devicesBrand Model Maximum capacity [m 3< / h] Mass [kg] Mass factor HeliosKWL EC 170 W160334,8MaicoWS 170 K, WS 170 KB16044,83,6SabianaENY-SP-180180473,8Prolux Solution AGAvero V180180473,8Salda UABSMARTY 2X V185257,4ValloxValloPlus 180 MV169602,8GDC Group LtdNatural Air 180 PH21819,811,0Pluggit GmbHAvent C 2002101514,0Bosch Termotechnik GmbHBosch Vent V5000C HR 140 W, Junkers Aerastar LP 140-2180365,0Zehnder Group Nederland BVComfoAir180 (V)188277,0Paulfocus 200200258,0SabianaENY-SP-280280515,5Prolux Solution AGAvero V280280535,3DanthermDantherm HCV 400-P1200405,0BauInfoCenter LijftungstechnikVentCube Fresh 200275406,9HeliosKWL EC 270270495,5Drexel und Weissaerosilent stratos300803,8Vaillant GmbHrecoVAIR 260 / 4260426,2SystemairSAVE VTC 200267475,7Waterkotte GmbHBasicVent 270270299,3Glen DimplexZL 300 VF280328,8ValloxValloPlus 270 MV320536,0Renson Ventilation nvEndura Delta 330 PH330418,0DanthermDantherm HCV 5375458,3WAFEWAFE 3503503510,0SabianaENY-SP-370370566,6WolfCWL-T-300 Excellent300506,0JABLOTRON LIVING TECHNOLOGY CZ s.r.o.Futura M250475,3P. Lemmens Company S.AHrmural UP ECO 3003002512,0Vortice ElettrosocialiVORT HR 450 AVEL D4004010,0Bosch Termotechnik GmbHBosch Vent V5000C HR 230 W30049,56,1SystemairSAVE VTR 300 (wymiennik obrotowy)367705,2SystemairSAVE VTR 250 (wymiennik obrotowy)307565,5BrinkBrink Flair 300300378,1PaulNovus 300300506,0ALDESDee Fly Cube 300300427,1BrinkRenovent Excellent 300 (Plus)300387,9ViessmannVitovent 300-F280803,5Kermix-well S360360507,2MaicoWR 310, WS 320 B, WS 320 K, WS 320 KB320674,8SystemairSAVE VTC 300300724,2BrinkBrink Flair 325325378,8ALDES AérauliqueInspirAIR Top 300 Classic3302811,8ALDES AérauliqueInspirAIR Top 300 Premium331418,1EXHAUSTO A / SVEX 40 T Classic3302811,8EXHAUSTO A / SVEX 40 T Premium331418,1ValloxValloPlus 350 MV349605,8Östberg Group ABHERU 100 T EC2 (wymiennik obrotowy)400705,7Nilan A / SComfort CT 300400596,8P. Lemmens Company S.AHrmural UP ECO 400 / Kwin4002516,0Zehnder Group Nederland BVComfoAir E 350 V350507,0JABLOTRON LIVING TECHNOLOGY CZ s.r.o.Futura L35047,57,4Renson Ventilation nvEndura Delta 380 PH380468,3Zehnder Group Nederland BVComfoAir Q350 HRV350507,0Stiebel Eltron GmbH & Co. KGLWZ 280 (Balance)350784,5Salda UABSMARTY 3X V4203910,8J.PichlerLG 350 V350566,3Vaillant GmbHrecoVAIR 360 / 4 E360428,6Blauberg Ventilatoren GmbHKomfort EC SB350 S11415666,3Waterkotte GmbHEcoVent 4004002913,8GenvexGenvex Eco 375 TL383409,6Zehnder Group Nederland BVComfoAir SL 330SV330635,2BrinkRenovent Excellent 4004003810,5Zehnder Group Nederland BVComfoAir350350399,0Titon HardwareHRV3 PH ECOaura37924,515,5HeliosKWL EC 370350526,7Ensy ASAHU-400 BV / BH (wymiennik obrotowy)47064,57,3BrinkRenovent HR Large4003212,5Spa SabianaENY SP 460460597,8Zehnder Group Nederland BVComfoAir5505504711,7REC Indovent ABBlue 4400974,1BrinkBrink Flair 4004003710,8Glen DimplexZL 400VF3803510,9Bosch Termotechnik GmbHBosch Vent V5000C HR 350W450637,1Pluggit GmbHPluggit Avent P 46045062,57,2Zehnder Group Nederland BVComfoair Q450HRV, ComfortVent Q450HRV450509,0PaulNovus 450450528,7J.PichlerLG 450 V450568,0RensonEndura Delta 450 PH450469,8ALDES AérauliqueInspirAIR Top 450 Classic4702816,8ALDES AérauliqueInspirAIR Top 450 Premium4704111,5MaicoWR410, WS470B, WS470K, WS470KB470677,0ValloxValloPlus 510 MV542886,2KlimorKCX 5005005010,0KlimorKCX + 8008006811,8Zehnder Group Nederland BVComfoAir Q600 HRV6005012,0ValloxValloPlus 850 MV9292004,6SystemairVTC 7007001514,6

[0044] For the results obtained (88 samples), a statistical analysis was carried out (Table 3), setting a 95% percentile at 13. 3 m 3< h -1< kg -1< (m 3< / h / kg). Table 3. Statistical analysispercentile00,250,50,750,90,951Mass factor [m 3< / h / kg]2,825,647,209,6311,7913,3416,79 Conclusions:

[0045] Devices with a support structure of the air handling unit made mainly of metal elements reach values below 8 m 3< h -1< kg -1< . It has been observed that the greater the proportion of foamed materials in the structure, the greater the coefficient is in principle. For the air handling unit according to the invention the mass factor value in the range of 11.9 -17.3 m 3< h -1< kg -1< was obtained.

[0046] This means that the support structure of the air handling unit made of EPP according to the invention allows to reduce the weight of the air handling unit by up to half, compared to units made in typical technology, with comparable operating parameters.References:

[0047] 1- Housing 1a, 1b - Fittings 2- Coating 3- Counter-current heat exchanger 4- Preheater 5, 6- Fans 7,8- Intake air filters 9- Exhaust air filter 10- Control system 11 - Bypass system

Claims

1. A supply-exhaust air handling unit, equipped with a housing, a counter-current heat exchanger, a fans, an exhaust air filters, a preheater, a bypass system and a control system, characterized in that the housing (1) consists of two fittings (1a, 1b) formed by injection method from foamed polypropylene, which are permanently bonded to each other by means of gluing, wherein the inner surface of the fittings (1a, 1b) is covered with a coating (2) having antistatic, antibacterial and antifungal properties, wherein the housing (1) being at the same time a supporting structure to which the other elements of the equipment of the air handling unit are mounted.

2. The air handling unit according to claim 1, wherein the coating (2) consist of a substrate-adhesion enhancing primer consisting of a 20% xylene-dispersed chlorinated polyolefin solution layer and a base layer consisting of at least one layer of a composition based on a two-component polyurethane solvent paint having a weight ratio of component A to B of 100:63, the quantitative and qualitative composition of components A and B being set forth in Table 1.

3. The air handling unit according to any one of claims 1-2, characterized in that the coating (2) exhibits adhesion to the inner surface of the fittings (1a, 1b) for testing according to PN-C / 89258-1:1997 using a self-adhesive tape having a width of 12 mm and a linear adhesion to steel of from 2 N / 25 mm to 5 N / 25 mm, as determined according to PN-C / 89258-1:1997 standard.

4. The air handling unit according to any one of claims 1-3, characterized in that the coating (2) exhibits antibacterial activity after 6 months of aging for Escherichia coli (ATCC 8739) and Staphyloccocus aureus (ATCC 6538 P) strains of 2,9 and 2,0, respectively, as determined according to ISO 22196:2011.

5. The air handling unit according to any one of claims 1-3, characterized in that the coating (2) exhibits antifungal activity after 6 months of aging for strains of Aspergillus niger (ATCC 6275), Penicillium pinophilum (ATCC 36839), Paecilomyces variotli (ATCC 18502), Trichoderma virens (ATCC 9645), Chaetomium globosum (ATCC 6205), visual assessment at level 0 / 1 and microscopic assessment at level 0, determined according to PN-EN ISO 846:2019.

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