ISHS Acta Horticulturae 456: II Modelling Plant Growth, Environmental Control and Farm Management in Protected Cultivation
FORMULATION AND SENSITIVITY ANALYSIS OF A DYNAMIC MODEL OF THE GREENHOUSE CLIMATE VALIDATION FOR A MILD MEDITERRANEAN CLIMATE |
| Authors: | L.M. Navas, S. de la Plaza, J.L. García, L. Luna, R. Benavente, J.M. Durán, N. Retamal |
| Keywords: | Energy transfer, Computer simulation, Numerical methods, Greenhouse Climate Simulation |
| Abstract:
In the present study the structure of a dynamic model of the greenhouse climate is described. The system in the model is divided into five components: growing medium, soil, crop, cover and inside air. By formulating the balance equations of energy and mass of each component, a set of differential equations is obtained. The equations are solved numerically by means of a computer programme. In order to predict the climate of a specific greenhouse, the programme asks the user for the physical characteristics of the system and the initial values of the simulated variables (temperatures of the growing medium and soil, temperature of the crop and cover, temperature and humidity of the inside air). The simulation interval lasts 1 min., therefore the values of the boundary variables (outside temperature and humidity, solar radiation, etc.) have to be supplied with the same frequency. The sensitivity analysis of the model as regards the boundary variables was achieved by means of the ex-post prediction of the environment of a greenhouse in Madrid (Spain). There the conditions were those of a mild Mediterranean climate. Results obtained show that the simulation is good. In addition, the predicted dynamics of all the simulated variables is correct. The sensitivity analysis as regards the initial prediction conditions shows that the model is practically insensitive to the errors in the measurement of the initial values of the simulated variables and consequently also indifferent to the moment when the predictions begin. | |
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