CSBE-SCGAB

Simulation-based control of enclosed ecosystems - a case study: determinatio 'of greenhouse heating setpor ts

Authors: R. Lacroix and R. Kok
Description: The overall objective of this study was to investigate the use ofa simulation-based approach for the control of enclosed ecosystems. To do this, a simulation-based controller was developed and implemented in a simulated greenhouse system. The role of the controller was to determine the setpoint path that would minimize the energy requirements for heating. It did this once a day, for the ensuing 24 hours, by simulating the greenhouse behavior in response to anticipated meteorological conditions. For each day a number of simulations were run for various setpoint scenarios and the most favorable scenario chosen. The greenhouse model that was used for these simulations was a neural network. The strategy used by the controller was based on the supposition that crops have a temperature integration capacity. Overall, the simulation-based controller allowed the greenhouse system to adapt itself to the anticipated disturbances and to behave more optimally than with a reference controller. It maintained high night temperatures when outside temperature and solar radiation intensity were anticipated to be low during the next day and vice-versa. This control approach reduced the average heating load by more than 7%. The results illustrate the adaptive capacity of a simulation-based controller and provides a basis for the use of this approach in various other types of enclosed ecosystems.
Citation: R. Lacroix and R. Kok 1999. SlMULATIO -BASED CONTROL OF ENCLOSED ECOSYSTEMS - A CASE STUDY:
DETERMINATIO 'OF GREENHOUSE HEATING SETPor TS. Canadian Agricultural Engineering 41(3):175-183.
Volume: 41
Issue: 3
Publisher: Canadian Society for Bioengineering
Date: 1999
Type: Text.Article
Format: PDF
Coverage: Canada
Language 1: en
Rights: Canadian Society for Bioengineering
Located in: Volume 41 (1999)