ISHS Acta Horticulturae 230: Symposium on High Technology in Protected Cultivation
GREENHOUSE CLIMATE CONTROL IN THE NINETIES |
| Authors: | H. Challa, Elly M. Nederhoff, G. P.A. Bot, Nico J. van de Braak |
| Abstract:
Because the cost of operation in modern, sophisticated greenhouses is high, optimal use of their potentials is essential. Traditionally the emphasis in research has been on the development of optimal blueprints for crop production where optimalization is pursued over longer periods of time. Optimal control of greenhouse climate, however, may benefit of a more dynamic approach. In The Netherlands a research programme is in progress, where optimalization techniques will be used to improve climate control in greenhouses in a dynamic way. In this multi-disciplinary project, crop and greenhouse performance are predicted with models. A physical model of the greenhouse predicts air temperature, crop temperature, radiation above the crop and CO2 -concentration and air humidity inside the greenhouse, as a function of greenhouse-, crop-, and control characteristics and outside weather conditions. The interaction with the activities of the crop are accounted for by a crop growth model that predicts the rate of CO2 uptake and transpiration by the crop. The crop growth model uses the output of the greenhouse model to predict the rate of production. The greenhouse model in addition calculates the rate of fuel and CO2 consumption and so all information required for economic optimalization is available. A general description of the models, the interactions of the models and the principles of the optimalization and control procedures will be given. Potentials, limitations and difficulties of this approach will be discussed and some preliminary results will be given. | |
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