Improving energy efficiency of a Plant Factory

Can plant growth be sustained under high temperatures when exposed to specific light spectra?
Plant Factory Cornwall
Title: Improving energy efficiency of a Plant Factory
Funding: Seale-Hayne Educational Trust
Duration: 2020
University of Plymouth staff: Dr Sophie Fauset (Co-PI); Dr Hail Rihan 
At the University of Plymouth’s Plant Factory, it has already been shown that using LED lighting matched to the absorption spectra of a plant can increase growth. However, within controlled environments considerable heat is generated by the lighting equipment and cooling the facility is a large component of the running costs. As leaf temperature is dependent on light radiation, as well as air temperature and humidity, specific 'light recipes’ could also help to reduce the amount of cooling required.
By eliminating wavelengths outside of the photosynthetically active band, we can enable plants to tolerate higher temperatures than expected. If plants can be grown in warmer environments, then the energy efficiency of the units increases, resulting in improved sustainability and cheaper costs. This project will measure plant temperature and growth under differing light spectra within a Plant Factory, compared with natural conditions outdoors.
A shelf of plants in the Plant factory

Objectives of the project

  • Assess the response of plant temperature of basil and lettuce to different combinations of light spectra within the Plant Factory.
  • Determine the relationship between light spectra, plant temperature and photosynthesis, and physiological parameters of the target species.
  • Quantify the relationship between plant temperature and yield.
  • Compare relationship between air temperature and plant temperature under equivalent photosynthetic conditions in both the Plant Factory and open field conditions.

Impacts of our research

*Updated following project completion
The outcomes of this research will have implications for the economics and sustainability of vertical farming facilities globally. By improving the efficiency of Plant Factory systems we have helped businesses interested in building and setting up these systems in response to food security concerns.
Combining renewable energy, vertical farming and LED technology will have a great impact on tackling issues related to climate change, carbon footprint and the environment. Learnings from our Plant Factory research is contributing to training the next generation of controlled environment scientists.
Image of a plant in the Plant Factory
 
 

Experiments in the Plant Factory

In this project, we ran a series of experiments where plants were exposed to differing light spectra, including a full white spectrum, spectra that match the requirements of basil and lettuce, and an industry standard. We monitored plant temperature (using hand-held infra-red cameras), stomatal conductance and yield, and investigated varying leaf sizes. In addition, we carried out a field trial growing target species under ambient conditions outdoors during the summer, to compare plant temperatures under solar radiation with those in the Plant Factory.
Throughout the experiments we monitored Plant Factory energy use. From these data, we are able to determine under which conditions plants produce the greatest yield, and what operating temperatures are able to balance yield against energy efficiency. The research provides a better understanding of how plant leaf temperature responds to various light spectra and this, in turn, will help to optimise growing conditions in order to minimize electrical consumption in controlled environment agriculture systems.

More research from the Plant Factory

Our Plant Factory uses novel LED technology to grow crops in controlled hydroponic systems, providing solutions for health, food and water security.

Lettuces growing in the Plant Factory

Plant Factory Cornwall
Prototyping automated, programmable ‘light recipes’ to accurately deliver the necessary requirements for plants during their differing growth stages.

Close up of a plant in the Plant Factory with LEDs

Towards the development of Plant Factories
Producing a standardised LED light system that can be readily adapted to grow high-value crops, including salads, herbs and medicinal plants.

multi pipette research of cancer stem cells

Optimisation of Plant Factory systems
The production of clean pharmaceutical plant species with a stable, consistent concentration of important secondary metabolic products.

 
 

Controlled Environment Agriculture Research Group

Our Controlled Environment Agriculture (CEA) team includes researchers and technical staff from both the Faculty of Science and Engineering and the Faculty of Health, working together on transdisciplinary projects advancing the use of dynamic lighting technology to grow food and medical crops.
Much of our research is carried out on-site in our bespoke Plant Factory unit. Projects focus on the development of sensors, LED lighting, control systems and precision horticulture techniques to optimise the energy efficiency of indoor growing and improve the yield and quality of target pharmaceutical compounds.
 
Wide shot of Plant Factory with LED lights on