Big Grower January 2020 - 9

To achieve consistent lighting conditions, a control algorithm was
GLASE researchers are working to learn more about how growers can take
advantage of greenhouse lighting spectrum control.
created that can predict the total solar (natural) DLI. Based on this
information, supplemental lights and movable shades can be adjusted via
the algorithm to achieve the optimal DLI every day. This control algorithm
was developed at Cornell University and is called LASSI, for Light and
Shade System Implementation.
In addition to providing consistent, predictable year-round production,
LASSI also has been proven to reduce the energy use of a greenhouse
when compared to other supplemental light control strategies such
as threshold control (turning the lights on/off when natural light is
below/above set targets). LASSI was implemented in two commercial
greenhouses in New York serving as GLASE pilots. A baseline will be
established and the energy efficiency improvements provided by LASSI
will be demonstrated.
Spectrum Control - The question of how the solar spectrum changes
over time is important for providing the best light environment for crop
production. Light is the energy source in photosynthesis and light also
serves as an important cue for developmental responses.
GLASE researchers at the Center for Lighting Enabled Systems and
Applications (LESA) at RPI have built a Spectral Acquisition Sensor
System (SASSy) that can measure variations in the composition of the
solar spectrum over the course of the day. Once we understand how
the spectrum of sunlight changes over time, GLASE researchers will
use tunable LED fixtures developed at LESA to study the benefits of
supplemental lighting spectrum control. The SASSy unit is currently
recording data in a greenhouse at Cornell University. It is one of the first
robust spectrometer systems created for recording solar spectrum in a
greenhouse over long time periods.
and Lighting control - In high density production CEA
operations, CO2 supplementation is often used to increase biomass
Researchers, growers and manufacturers are working together to accelerate
the implementation of new energy efficient technologies
production. GLASE researchers at Cornell University are studying
lettuce, tomato and strawberry biomass responses to light levels and CO2
concentration. The findings from the CO2
existing LASSI control software to simultaneously control CO2
and supplemental lighting. The new " CO2
LASSI " will allow growers to
optimize crop production management to help reduce supplemental
lighting requirements.
Integrated Controls - Lighting is often controlled in conjunction with
other environmental factors using climate control systems. Replacing a
lighting system (e.g., replacing HPS bulbs with LED fixtures) or modifying
the lighting control strategy (e.g., DLI control vs. threshold or timer
control) will affect other production factors. For example, a semi-closed
greenhouse uses a small mechanical cooling system at certain times of
the year to remove latent heat, thereby reducing ventilation and waste of
supplemental CO2
To determine the impacts of new energy efficient technologies,
GLASE researchers are improving existing energy modeling software to
accommodate the use of integrated climate management strategies. The
new software will allow CEA growers to simulate complicated heating,
ventilation, and air conditioning (HVAC) systems that can account for the
impacts of heat load differences between LED and HPS lighting systems
and the use of integrated CO2
enrichment systems.
The Spectral Acquisition Sensor System (SASSy) measures the variations in the
composition of the solar spectrum over the course a a day.
efficiency. Following are some of the new technologies being developed
at GLASE to improve lighting management and climate control in CEA
Supplemental Lighting System Control - More than any other
environmental variable, the total sum of light received by the plants
in a 24-hour period determines the rate that the plants grow and thus
the amount of product available for sale. The total amount of incident
light is measured as the daily light integral (DLI), the number of
photosynthetically active photons reaching the plant per day. Due to
weather variability, growers often experience decreased crop production
in the winter due to low natural lighting conditions, whereas produce
damage can be experienced during the summer due to excess light.
To help facilitate technology implementation, GLASE has developed an
outreach program to support technology manufacturers and CEA growers
by providing scientific based information and industry insights with the
goal of getting new technologies quickly to the market.
The outreach program is designed to bridge the gap between academia
and industry, in this way keeping growers and manufacturers informed
about the latest technologies through a series of webinars featuring
new scientific and technological innovations and best practices in
the CEA industry. In addition to the opportunity to work with other
GLASE members to develop new opportunities for all, GLASE members
participate in the consortium Industrial Advisory Board meetings, which
are held on a quarterly basis.
To find out more about the consortium activities and how to get involved
please visit
Erico Mattos is executive director of GLASE. He can be reached at em796@
JANUARY 2020 9
trials will be integrated into the

Big Grower January 2020

Table of Contents for the Digital Edition of Big Grower January 2020

Big Grower January 2020 - 1
Big Grower January 2020 - 2
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