Effect of material ageing and dirt on the behaviour of greenhouse insect-proof screens
Abstract
The present work examines the variations in the aerodynamic characteristics of four insect-proof screens by means of wind tunnel tests and digital image processing. The tested insect-proof screens were examined in three different conditions: (i) in their new, unused state; (ii) under conditions of accumulated dust and dirt after a period of 3 to 4 years of use; and (iii) under clean conditions after a period of 3 to 4 years of use and a cleaning treatment with high-pressure water. The deterioration of the screens caused the mesh to become less tense, therefore increasing its thickness and improving its aerodynamic behaviour despite a slight increase of the thread diameter and a subsequent decrease of the 2-dimensional porosity. The pressure drop coefficient, Fφ, of the used but clean screens was 1.5% to 8.8% lower (for u=1.0 m/s) than that of the new ones, thus increasing the discharge coefficient, Cd,φ, by between 0.8% and 4.8% as a result of the presence of the screens. On the other hand, comparison of the used screens in their clean and unclean states showed that the accumulation of dirt has a major bearing on their aerodynamic characteristics: Fφ increased by between 16.5% and 61.2% (for u=1.0 m/s) for the unclean screens, resulting in a Cd,φ reduction of between 7.5% and 21.3% and therefore a lower natural ventilation capacity of the greenhouse. A regular cleaning treatment of the insect-proof screens is a simple measure that improves the natural ventilation capacity of the greenhouse.
Downloads
References
Álvarez AJ, Oliva RM, Valera DL, 2012. Software for the geometric characterisation of insect-proof screens. Comput Electron Agr 82: 134-144. https://doi.org/10.1016/j.compag.2012.01.001
Baker JR, Jones RK, 1989. Screening as part of insect and disease management in the greenhouse. NC Flower Growers' Bulletin 34: 1-9. https://hortscans.ces.ncsu.edu/uploads/s/c/screenin_53e4f3cf4132a.pdf [10 April 2017]
Baker JR, Shearin EA, 1994. An update on screening for the exclusion of insect pests. NC Flower Growers' Bulletin 39 (2): 6-11. http://hortscans.ces.ncsu.edu/library/floriculture/doc_id/3625/An-Update-on-Screening-for-the-Exclusion-of-Insect-Pests.pdf [10 April 2017]
Chu CR, Lan TW, Tasi RK, Wu TR, Yang CK, 2017. Wind-driven natural ventilation of greenhouses with vegetation. Biosyst Eng 164: 221-234. https://doi.org/10.1016/j.biosystemseng.2017.10.008
Dierickx IE, 1998. Flow reduction of synthetic screens obtained with both a water and airflow apparatus. J Agr Eng Res 71: 67-73. https://doi.org/10.1006/jaer.1998.0299
Espinoza K, Valera DL, Torres JA, López A, Molina-Aiz FD, 2015. An auto-tuning PI control system for an open-circuit low-speed wind tunnel designed for greenhouse technology. Sensors 15: 19723-19749. https://doi.org/10.3390/s150819723
Fatnassi H, Boulard T, Demrati H, Bouirden L, Sappe G, 2002. Ventilation performance of a large Canarian-type greenhouse equipped with insect-proof nets. Biosyst Eng 82 (1): 97-105. https://doi.org/10.1006/bioe.2001.0056
Forchheimer P, 1901. Wasserbewegung durch Boden [Water movement from ground]. Z Ver Dtsch Ing 45: 1782-1788.
Kitta E, Baille AD, Katsoulas N, Rigakis N, González-Real MM, 2014. Effects of cover optical properties on screenhouse radiative environment and sweet pepper productivity. Biosyst Eng 122: 115-126. https://doi.org/10.1016/j.biosystemseng.2014.04.001
Kittas C, Katsoulas N, Bartzanas T, Mermier M, Boulard T, 2008. The impact of insect screens and ventilation openings on the greenhouse microclimate. T ASABE 51 (6): 2151-2165. https://doi.org/10.13031/2013.25396
Kosmos SR, Riskowski GL, Christianson LL, 1993. Force and static pressure resulting from airflow through screens. T ASAE 36 (5): 1467-1472. https://doi.org/10.13031/2013.28487
Linker R, Tarnopolsky M, Seginer I, 2002. Increased resistance to flow and temperature-rise resulting from dust accumulation on greenhouse insect-proof screens. Proc ASAE Annu Int Meet, Jun 28-31; Chicago (USA); Paper 024040; 9 pp.
López A, Valera DL, Molina-Aiz FD, Peña A, 2012. Sonic anemometry measurements to determine airflow patterns in multi-tunnel greenhouse. Span J Agric Res 10 (3): 631-642. https://doi.org/10.5424/sjar/2012103-660-11
López A, Valera DL, Molina-Aiz FD, Peña A, Marín P, 2013. Field analysis of the deterioration after some years of use of four insect-proof screens utilized in Mediterranean greenhouses. Span J Agric Res 11 (4): 958-967. https://doi.org/10.5424/sjar/2013114-4093
López A, Valera DL, Molina-Aiz FD, Peña A, Marín P, 2014. Microclimate evaluation of a new design of insect-proof screens in a Mediterranean greenhouse. Span J Agric Res 12 (2): 338-352. https://doi.org/10.5424/sjar/2014122-4956
López A, Molina-Aiz FD, Valera DL, Peña A, 2016. Wind tunnel analysis of the airflow through insect-proof screens and comparison of their effect when installed in a Mediterranean greenhouse. Sensors 16: 690. https://doi.org/10.3390/s16050690
Miguel AF, Van de Braak NJ, Bot GPA, 1997. Analysis of the airflow characteristics of greenhouse screening materials. J Agr Eng Res 67: 105-112. https://doi.org/10.1006/jaer.1997.0157
Molina-Aiz FD, Valera DL, Peña AA, Gil JA, 2005. Optimisation of Almería-type greenhouse ventilation performance with computational fluid dynamics. Acta Hortic 691: 433-440. https://doi.org/10.17660/ActaHortic.2005.691.52
Molina-Aiz FD, Valera DL, Álvarez AJ, Madueño A, 2006. A wind tunnel study of airflow through horticultural crops: determination of the drag coefficient. Biosyst Eng 93 (4): 447-457. https://doi.org/10.1016/j.biosystemseng.2006.01.016
Molina-Aiz FD, Valera DL, Peña AA, Gil JA, López A, 2009. A study of natural ventilation in an Almería-type greenhouse with insect screens by means of tri-sonic anemometry. Biosyst Eng 104: 224-242. https://doi.org/10.1016/j.biosystemseng.2009.06.013
Montero JI, Muñoz P, Antón A, 1997. Discharge coefficients of greenhouse windows with insect-proof screens. Acta Hortic 443: 71-77. https://doi.org/10.17660/ActaHortic.1997.443.8
Muñoz P, Montero JI, Antón A, Giuffrida F, 1999. Effect of insect-proof screens and roof openings on greenhouse ventilation. J Agr Eng Res 73: 171-178. https://doi.org/10.1006/jaer.1998.0404
Nield DA, Bejan A, 1998. Convection in porous media. Springer, NY, USA.
Sangpradit K, 2014. Study of the solar transmissivity of plastic cladding materials and influence of dust and dirt on greenhouse cultivations. Energy Procedia 56: 566-573. https://doi.org/10.1016/j.egypro.2014.07.194
Soni P, Salokhe VM, Tantau HJ, 2005. Effect of screen mesh size on vertical temperature distribution in naturally ventilated tropical greenhouses. Biosyst Eng 92 (4): 469-482. https://doi.org/10.1016/j.biosystemseng.2005.08.005
Reyes-Rosas A, Molina-Aiz FD, Valera DL, López A, Khamkure S, 2017. Development of a single energy balance model for prediction of temperatures inside a naturally ventilated greenhouse with polypropylene soil mulch. Comput Electron Agr 142: 9-28. https://doi.org/10.1016/j.compag.2017.08.020
Teitel M, 2001. The effect of insect-proof screens in roof openings on greenhouse microclimate. Agr Forest Meteorol 110: 13-25. https://doi.org/10.1016/S0168-1923(01)00280-5
Teitel M, 2007. The effect of screened openings on greenhouse microclimate. Agr Forest Meteorol 143 (3-4): 159-175. https://doi.org/10.1016/j.agrformet.2007.01.005
Teitel M, 2010. Using computational fluid dynamics simulations to determine pressure drops on woven screens. Biosyst Eng 105: 172-179. https://doi.org/10.1016/j.biosystemseng.2009.10.005
Teitel M, Shklyar A, 1998. Pressure drop across insect-proof screens. T ASAE 41 (6): 1829-1834. https://doi.org/10.13031/2013.17336
Valera DL, Molina FD, Álvarez AJ, López JA, Terrés-Nicoli JM, Madueño A, 2005. Contribution to characterization of insect-proof screens: experimental measurements in wind tunnel and CFD simulation. Acta Hortic 691: 441-448. https://doi.org/10.17660/ActaHortic.2005.691.53
Valera DL, Álvarez AJ, Molina FD, 2006. Aerodynamic analysis of several insect-proof screens used in greenhouses. Span J Agric Res 4 (4): 273-279. https://doi.org/10.5424/sjar/2006044-204
Valera DL, Belmonte LJ, Molina-Aiz FD, López A, 2016. Greenhouse agriculture in Almería. A comprehensive techno-economic analysis, Cajamar Caja Rural, Almería, Spain. http://www.publicacionescajamar.es/series-tematicas/economia/greenhouse-agriculture-in-almeria-a-comprehensive-techno-economic-analysis/ [10 April 2017]
Wang Q, Mazé B, Tafreshi HV, Pourdeyhimi B, 2007. On the pressure drop modeling of monofilament-woven fabrics. Chem Eng Sci 62 (17): 4817-4821. https://doi.org/10.1016/j.ces.2007.06.001
© CSIC. Manuscripts published in both the printed and online versions of this Journal are the property of Consejo Superior de Investigaciones Científicas, and quoting this source is a requirement for any partial or full reproduction.
All contents of this electronic edition, except where otherwise noted, are distributed under a “Creative Commons Attribution 4.0 International” (CC BY 4.0) License. You may read here the basic information and the legal text of the license. The indication of the CC BY 4.0 License must be expressly stated in this way when necessary.
Self-archiving in repositories, personal webpages or similar, of any version other than the published by the Editor, is not allowed.
