A Light and CO2 Controller to Optimize Energy Efficiency in Commercial Greenhouses

This project is to develop a marketable environmental controller to improve the productivity, energy-efficiency and cost-effectiveness of locally produced fresh vegetables and other crops in greenhouses. Plant growth requires light but, in many regions of the U.S., winter cloudiness (or a more northerly latitude) limits greenhouse productivity. Supplementing carbon dioxide makes light more effective and less is required. However, ventilation for temperature control wastes CO2 and supplemental lighting becomes the less expensive alternative. Real-time, adaptive, control that optimizes the combination, yet provides identical plant productivity, has significant value. Our first goal is to validate an algorithm to control the daily light integral and CO2 concentration in a greenhouse where the algorithm will control CO2 concentration and the daily light integral target in the most effective and efficient way. Previous work, based on computer simulations using the algorithm, predict supplemental lighting cost can be reduced by approximately half in cold and cloudy regions such as upstate NY. The project outcome will be a stand-alone controller that permits real time, adaptive, control of the daily light integral and CO2 concentration in commercial greenhouses to grow crops of consistent high quality and size, while significantly reducing electricity required for supplemental lighting.