Articles
RECENT TRENDS IN GREENHOUSE MICROCLIMATE STUDIES AND CONTRIBUTION OF CFDS
Article number
952_93
Pages
739 – 748
Language
English
Abstract
Based on a bibliographic analysis on the recent greenhouse micro-climate studies, it is shown that the publications in that field still increase whereas Computer Fluid Dynamics (CFD) studies about greenhouses have a tendency to stagnate or slightly regress.
Since 2007, most of the published studies (57%) are based on a dual modeling plus experimental approach, the remainder concerning pure experimental studies.
The studies deal principally with questions of greenhouse cooling or screening and to a lesser extend of heating and crop transpiration.
Substantial advances have been observed in the field of experimental characterization using wireless sensors and of the exploitation of these data by means of geostatistical methods for climate and plant activity.
There are also substantial progresses in CFD assisted characterization of the phenomena occurring in greenhouses, particularly concerning (i) the characterization of the distributed climate in very large scale (1 ha or more) greenhouses, (ii) the CFD modeling of very intricate geometries such as weaved screens or cellulose evaporative cooling pads or (iii) complex phenomena involving coupled mechanisms such as fogging and ventilation or fungal spores transfer in greenhouses.
The question of radiative transfers within greenhouses prompts renewed interest.
It aims either to a revisit of the general relations for estimating the amounts of solar energy absorbed by the greenhouse components or to a numerical modeling of the radiative transfers.
The first approach highlights the considerable amount of incident radiation which is reflected to outside the greenhouse and should be considered in the thermal analysis of greenhouses, whereas the numerical approach ends at a numerical coupling of radiative and convective transfer equations for a very precise description of climate conditions at both greenhouse and crop cover levels.
Finally, the contributions of these recent progresses are examined with respect to the improvement of the climate conditions in the major production systems designed to cope with greenhouse sustainability: closed energy saving greenhouses for Northern latitudes and simple Canarian type shelters for Southern ones.
Since 2007, most of the published studies (57%) are based on a dual modeling plus experimental approach, the remainder concerning pure experimental studies.
The studies deal principally with questions of greenhouse cooling or screening and to a lesser extend of heating and crop transpiration.
Substantial advances have been observed in the field of experimental characterization using wireless sensors and of the exploitation of these data by means of geostatistical methods for climate and plant activity.
There are also substantial progresses in CFD assisted characterization of the phenomena occurring in greenhouses, particularly concerning (i) the characterization of the distributed climate in very large scale (1 ha or more) greenhouses, (ii) the CFD modeling of very intricate geometries such as weaved screens or cellulose evaporative cooling pads or (iii) complex phenomena involving coupled mechanisms such as fogging and ventilation or fungal spores transfer in greenhouses.
The question of radiative transfers within greenhouses prompts renewed interest.
It aims either to a revisit of the general relations for estimating the amounts of solar energy absorbed by the greenhouse components or to a numerical modeling of the radiative transfers.
The first approach highlights the considerable amount of incident radiation which is reflected to outside the greenhouse and should be considered in the thermal analysis of greenhouses, whereas the numerical approach ends at a numerical coupling of radiative and convective transfer equations for a very precise description of climate conditions at both greenhouse and crop cover levels.
Finally, the contributions of these recent progresses are examined with respect to the improvement of the climate conditions in the major production systems designed to cope with greenhouse sustainability: closed energy saving greenhouses for Northern latitudes and simple Canarian type shelters for Southern ones.
Authors
T. Boulard
Keywords
greenhouse, CFD, modelling, airflow, microclimate, light, temperature, humidity, CO2
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