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Environmental Control Systems. Evolution, Current Systems, the Future. Click on images to go to original URL. What can be regulated?. Temperature (heat/cooling systems) Humidity Supplemental Lighting Photoperiod (day length extension or black cloth)
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Environmental Control Systems Evolution, Current Systems, the Future Click on images to go to original URL
What can be regulated? • Temperature (heat/cooling systems) • Humidity • Supplemental Lighting • Photoperiod (day length extension or black cloth) • Atmospheric composition (CO2 enrichment) • Irrigation • Nutrient Delivery (Fertilization)
Types of Controls • Manual • On/off Switches • Step Controllers • Dedicated Microprocessors • Computers (Integrated Control)
Manual Greenhouse Control • Common before 1950 to have people 24/7 to monitor temperature (winter) • Manual ventilation, heat valves • Manual pulling of shade cloth • Manual sun shades • Hand watering
On/Off Switches • Simple • For heating and cooling based on a thermostat • Problems with accuracy • May still be suitable for simple season extension houses • Many styles and manufacturers available
Step Controller • Advancement over on/off switch • Instead of just one option there are multiple stages possible (for example) • Stage 1 – louvered vent opens • Stage 2 – exhaust fan on opposite wall on low speed • Stage 3 – exhaust fan on opposite wall on high speed • Not expandable • Not good for complicated temperature control schemes • Can be difficult to ‘set up’ and ‘change’
Computers • Despite cost effectiveness and ease of use 85% of greenhouses still have some manual controls • Cost 5 to 7K and up • Very expandable • System can grow with your operation • Data can be easily made available to others for troubleshooting • Integrated record keeping
IFAC TECHNICAL BOARD AUGUST, 2003 IFAC EMERGING AREAS PROJECT CC 8: BIO & ECOLOGICAL SYSTEMS (APPLICATIONS) Keith Godfrey (for Ewart Carson)
TC 8.1 Control and Automation in Agriculture • “Speaking animals” Automated measurement of the responses of individual animals to differing feeding and climate regimes so as to optimise their management • “Speaking plants” Automated measurement of plant responses to different treatments for the purpose of automatic control of processes in the soil-substrate-plant continuum • Automation of harvesting and handling of crops Developments required due to a lack of skilled, affordable labour • Automation for tracking and tracing of products and of the production condition Stage of maturity, variability, treatments etc.