Effect of wind direction on greenhouse ventilation rate, airflow patterns and temperature distributions

The effect of wind direction, relative to a multi-span naturally ventilated greenhouse, on the airflow patterns and air temperature distribution inside the house and at the openings is investigated in the present study, in a greenhouse with vertical roof openings. Experiments in a full-scale greenhouse, CFD (Computational Fluid Dynamics) full-scale simulations and wind tunnel tests on a small-scale model were carried out. The results showed a significant effect of the wind direction on the flow patterns both inside the house and at the roof openings. Furthermore, wind direction significantly affected the ventilation rate and the air and crop temperature distributions. A reasonable qualitative agreement was achieved between the experiments, numerical simulations and wind tunnel tests with respect to flow patterns through the openings. Quantitatively, the numerically predicted ventilation rates are in reasonable agreement with estimates of ventilation rates obtained by a model given in the literature. However, numerically predicted air velocities at the greenhouse openings differ from the measured values and possible reasons for the differences are highlighted and discussed.

[1]  J. Tanny,et al.  Natural ventilation of greenhouses: experiments and model , 1999 .

[2]  B. Launder,et al.  The numerical computation of turbulent flows , 1990 .

[3]  J. C. Roy,et al.  CFD PREDICTION OF THE NATURAL VENTILATION IN A TUNNEL-TYPE GREENHOUSE: INFLUENCE OF WIND DIRECTION AND SENSIBILITY TO TURBULENCE MODELS , 2005 .

[4]  Thierry Boulard,et al.  Effect of Roof and Side Opening Combinations on the Ventilation of a Greenhouse Using Computer Simulation , 2007 .

[5]  Shaojin Wang,et al.  AIRFLOW PATTERNS AND ASSOCIATED VENTILATION FUNCTION IN LARGE-SCALE MULTI-SPAN GREENHOUSES , 1999 .

[6]  Pietro Picuno,et al.  Analysis of the efficiency of greenhouse ventilation using computational fluid dynamics , 1997 .

[7]  Shaojin Wang,et al.  Experimental and numerical studies on the heterogeneity of crop transpiration in a plastic tunnel , 2002 .

[8]  T. Takakura,et al.  Wind tunnel testing on airflow and temperature distribution of a naturally ventilated greenhouse. , 1984 .

[9]  P. Linden.  THE FLUID MECHANICS OF NATURAL VENTILATION , 1999 .

[10]  Thierry Boulard,et al.  Greenhouse natural ventilation by wind forces. , 2000 .

[11]  J. B Campen,et al.  Determination of greenhouse-specific aspects of ventilation using three-dimensional Computational Fluid Dynamics , 2003 .

[12]  Diego L. Valera,et al.  A Wind Tunnel Study of Airflow through Horticultural Crops: Determination of the Drag Coefficient , 2006 .

[13]  Thierry Boulard,et al.  Analysis of Greenhouse Ventilation Efficiency based on Computational Fluid Dynamics , 2006 .

[14]  J. Tanny,et al.  Airflow Patterns through Roof Openings of a Naturally Ventilated Greenhouse and their Effect on Insect Penetration , 2005 .

[15]  J. B. Campen.  Ventilation of small multispan greenhouse in relation to the window openings calculated with CFD , 2006 .

[16]  Thierry Boulard,et al.  Air-flow patterns and heat fluxes in roof-ventilated multi-span greenhouse with insect-proof screens , 2004 .

[17]  Gennady Ziskind,et al.  Induced ventilation of a one-story real-size building , 2004 .

[18]  Juan Ignacio Montero,et al.  DISCHARGE COEFFICIENTS OF GREENHOUSE WINDOWS WITH INSECT-PROOF SCREENS , 1997 .

[19]  Da-Wen Sun,et al.  Applications of computational fluid dynamics (CFD) in the modelling and design of ventilation systems in the agricultural industry: a review. , 2007, Bioresource technology.

[20]  Shaojin Wang,et al.  Air speed profiles in a naturally ventilated greenhouse with a tomato crop , 1999 .

[21]  Shaojin Wang,et al.  Lee-side Ventilation-induced Air Movement in a Large-scale Multi-span Greenhouse , 1999 .

[22]  THE INFLUENCE OF WIND DIRECTION ON GREENHOUSE VENTILATION , 2004 .

[23]  G. Ziskind,et al.  Experimental Verification of Induced Ventilation , 2005 .

[24]  T. W. Davies,et al.  Using CFD to model the internal climate of greenhouses: past, present and future , 2002 .

[25]  Thierry Boulard,et al.  Optimisation of Greenhouse Insect Screening with Computational Fluid Dynamics , 2006 .

[26]  Diego L. Valera,et al.  Measurement and simulation of climate inside Almerı́a-type greenhouses using computational fluid dynamics , 2004 .

[27]  In-Bok Lee,et al.  Prediction of natural ventilation of multi-span greenhouses using CFD techniques and its verification with wind tunnel test. , 2000 .

[28]  Juan Ignacio Montero,et al.  COMPUTATIONAL FLUID DYNAMIC MODELING TO IMPROVE THE DESIGN OF THE SPANISH PARRAL STYLE GREENHOUSE , 2005 .

[29]  C. Kittas,et al.  Air flow and associated sensible heat exchanges in a naturally ventilated greenhouse , 1997 .

[30]  A. Shklyar,et al.  Numerical model of the three-dimensional isothermal flow patterns and mass fluxes in a pitched-roof greenhouse , 2004 .

[31]  P. Richards,et al.  Appropriate boundary conditions for computational wind engineering models using the k-ε turbulence model , 1993 .

[32]  Thierry Boulard,et al.  Simulation of climatic conditions in full-scale greenhouse fitted with insect-proof screens , 2003 .

[33]  Thierry Boulard,et al.  Effect of Vent Arrangement on Windward Ventilation of a Tunnel Greenhouse , 2004 .

[34]  M. Teitel,et al.  INSECT-PROOF SCREENS IN GREENHOUSES: THEIR EFFECT ON ROOF VENTILATION AND INSECT PENETRATION , 1999 .

[35]  G. Papadakis,et al.  The mechanisms involved in the natural ventilation of greenhouses , 1996 .

[36]  Shaojin Wang,et al.  SE—Structures and Environment: Convective and Ventilation Transfers in Greenhouses, Part 2: Determination of the Distributed Greenhouse Climate , 2002 .

[37]  Gennady Ziskind,et al.  Ventilation by natural convection of a one-story building , 2002 .