Environmental Control SystemsEvolution, 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’

Dedicated Microprocesssors

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 AREASPROJECT

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 cropsDevelopments required due to a lack of skilled, affordable

labour• Automation for tracking and tracing of products and

of the production conditionStage of maturity, variability, treatments etc.