Progress 09/01/17 to 08/31/18
Outputs
Target Audience:We have reached out to greenhouse growers and energy consultants to inform them about the smart lighting controller we have developed as part of this project. Changes/Problems:We have postponed the development of the next generation lighting controllers until Spring/Summer 2019. We in itially planned to pursue that objective at this time. However, we decided that getting input and guidance from end users is critical to the success of the next generation controllers. It is critical that the next generation controllers meet the needs of our target customers and developing the 2nd generation controllers now would like result in a product that does not meet our customers' requirements and/or preferences. What opportunities for training and professional development has the project provided?Two graduate students at the University of Georgia are involved in this project. One of them is getting training in horticultural science and plant physiology, while the other student is getting trained in electrical engineering and optical sciences. How have the results been disseminated to communities of interest?Only a small part of our work has been shared publicly. Since we are currently in product development, we are keeping the specifics of our lighting control hardware and software secret. Results from the horticultural research on the use of dynamic lighting control technology has been shared at two plant science meetings (Annual Meeting of the Committee on Controlled Environment Technology and Use and the 2018 Conference of the American Society for Horticultural Science) What do you plan to do during the next reporting period to accomplish the goals?The upcoming winter we will focus on a number of trials in commercial greenhouses to determine how well our technology performs in a commercial setting. As part of these trials, we will collect feedback and input from end-users to improve the design and performance of our controllers. This information will be used to develop the next-generation controllers with improved performance and a more intuitive user interface. The next generation controllers will be ready for commercial use in Fall 2019. In year 2, we will also integrate our next generation controllers into commercial, third party greenhouse envirionmental control systems. We expect to finalize a fully-automated, stand-alone system to determine crop-specific photochemical responses to different light levels, which can be used to develop optimal lighting strategies.
Impacts
What was accomplished under these goals?
Candidus' objective is to develop an adaptive supplemental lighting control system based on the research done in partnership with the University of Georgia to bring the benefits of the biofeedback system to CEA facilities. Our system will maintain pre-determined crop-specific optimum light levels accordingly to crops light use efficiency and local weather conditions. Our goal is to implement lighting strategies to provide all the benefits of crop production consistency, shorter crop cycles, and increased productivity provided by supplemental lighting system at lower energy consumption than current technologies. The high precision lighting control system will allow for temporal and spatial resolution of a multi-species CEA production facility by a programmable multi-fixture lighting system. By the end of Phase II, Candidus will have developed a method to determine crop specific lighting recommendation, an efficient cloud-connected adaptive lighting control system and a platform of microcontroller enabled LED lights. To reach this goal, we are working towards six different objectives: Biofeedback system:An autonomous system to determine crops' light use efficiency (LUE).We have examined and compared two detection systems to measure chlorophyll fluorescence, which can be used to determine a plant's light use efficiency: free-space optics and an optical fiber optic-based system. The fiber optic-based system is near completion and its readings showexcellent agreement with a reference instrument. We will continue to pursue both approaches, since free space optics have some practical advantages. Lighting Profiles:A method to determine lighting strategies based on a crop's LUE. We have collected photochemical LUE curves on over 10 different species, both in a greenhouseand under precisely controlled environmentalconditions. There are clear differences in how different species respond to a range of light levels, which can be used to determine crop specific lighting recommendations. For lettuce, we have conducted an in-depth greenhouse study to link short-term LUE measurements to daily photosynthesis and light levels. This has resulted in a way to determine crop-specific targets for the total amount of photochemistry we can expect from a specific crop. That in turn can be used to determine a lighting profile for that crop. Validation:Test lighting profile recommendations on long term full crop growth cycle.We have tested different lighting approaches for a range of crops. Based on the lighting profiles we developed (see previous objective), we speculated that spreading the provided light out over longer photoperiods (i.e., lower instantaneous light levels, but for longer periods, resulting in the same amount of light over the entire day) would enhance crop growth. We have indeed confirmed this withlettuce, mizuna and basil, which all produce more biomass by spreading out the DLI over longer photoperiods inside of a growth chamber under steady-state conditions. The effect of adaptive lighting has been tested in a greenhouse in multiple studies with lettuce and bedding plants. Results so far have not been entirely consistent. In some cases, we sawbetter growth with adaptive lighting control, while in other cases we did not. However, we did see in all studies that the adaptive lighting control system works very well and can provide consistent daily light levels to a crop. That consistency is important, because it eliminates uncertainty and will help growers with scheduling their crop production cycles. Adaptive Light Control:Adaptive lighting control system to maintain crops' lighting profiles. We have developeda plug & play adaptive lighting controller whichprovidesa dimming signal for LED drivers. The controller can operate on battery power (4AA) or 12-24 volt supplied power.Designed to operate in a hot, humid crop production environment, the controller is waterproof (IP67 rated enclosure). The main components of the controller include anintegrated photodiodeand processor. The controller has been tested with commercial LED lights and can successfully control such lights by sending a dimming signal to the driver of the lights. Central Control system:Cloud-connected multi-fixture light control system for multi-crops production.The light controller can set the dimming level via two different, proprietary mechanisms. This allows for the use of commercially available lighting dimming modules to control several lights using only one Candidus light controller. This simplifies large scale installations and reduces production costs. This also results in increased flexibility of lighting layouts in the greenhouse, allowing lights to be easily grouped together and programmed for different crops.A cellular device acts as gateway for data collection and monitoring the operation of the light controller. The application monitors anduploads data to a web-baseddatabase. The data is used to monitor operations and reportpower usage information to the grower. Integration:Integration with commercial CEA control systems and commercial lighting fixtures. This goal will be pursued in year two. To test the performance of these lighting controllers, we are currently setting up pilot projects in five different greenhouses. The goal is to determine how well the system performs in commercial production settings and to get feedback from end-users in needed improvements in performance and user interface.
Publications
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