Articles
´INVERSIM´: A SIMULATION MODEL FOR A GREENHOUSE
Article number
719_30
Pages
271 – 278
Language
English
Abstract
The central region of Argentina is characterized by a temperate climate with a sudden increase of maximum temperature after winter that brings outstanding problems in the yield and quality of most greenhouse crops during the warm season.
The prediction of the greenhouse climate is essential to improve the design of these structures and their environmental control. ´InverSim´ is a mathematical model that simulates the hourly evolution of the air temperature and humidity inside the greenhouse during the whole day.
It is based on two equations describing the balances of sensible heat and water vapour, from which the unknown variables (inside air temperature and humidity) are derived.
The model accounts for (i) the greenhouse air exchange by ventilation and (ii) the influence of a fogging system, allowing the amount of water required to maintain the air temperature below a given threshold to be calculated.
However, in this work the effect of fogging system was not validated. The crop transpiration was considered as a linear function of solar radiation and vapour pressure deficit.
For the validation of this model, climate data collected over a 12-day period outside and inside a greenhouse with a metal structure, were used as input for the model.
There was good overall agreement between the observed and predicted values of temperature and relative humidity, with values of R2 higher than 0.88 for the air temperature and 0.70 for the relative humidity.
The root mean square error (RMSE) used to test the average differences between the predicted and the observed values of air temperature and humidity was 3.9° C and 11.8 %, respectively.
The results achieved with the model are discussed and their applicability addressed.
The prediction of the greenhouse climate is essential to improve the design of these structures and their environmental control. ´InverSim´ is a mathematical model that simulates the hourly evolution of the air temperature and humidity inside the greenhouse during the whole day.
It is based on two equations describing the balances of sensible heat and water vapour, from which the unknown variables (inside air temperature and humidity) are derived.
The model accounts for (i) the greenhouse air exchange by ventilation and (ii) the influence of a fogging system, allowing the amount of water required to maintain the air temperature below a given threshold to be calculated.
However, in this work the effect of fogging system was not validated. The crop transpiration was considered as a linear function of solar radiation and vapour pressure deficit.
For the validation of this model, climate data collected over a 12-day period outside and inside a greenhouse with a metal structure, were used as input for the model.
There was good overall agreement between the observed and predicted values of temperature and relative humidity, with values of R2 higher than 0.88 for the air temperature and 0.70 for the relative humidity.
The root mean square error (RMSE) used to test the average differences between the predicted and the observed values of air temperature and humidity was 3.9° C and 11.8 %, respectively.
The results achieved with the model are discussed and their applicability addressed.
Publication
Authors
C.A. Bouzo, N.F. Gariglio, R.A. Pilatti, D.A. Grenon, J.C. Favaro, E.R. Bouchet, C. Freyre
Keywords
mathematical model, greenhouse climate, air temperature, relative humidity
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