Liquid Crystal Research Partnership
Frequently Asked Questions
What is liquid crystal technology?
A liquid crystal is a tiny organic substance derived from numerous biological materials. The original liquid crystals were a derivative of cholesterol. Today, highly purified forms of liquid crystals are manufactured by pharmaceutical companies. Basically, liquid crystal glazing technology is like an electronically controlled fog. In nature, air is the carrier of tiny water particles. With this technology, a polyresin polymer is the carrier and the particles are liquid crystals. This very thin matrix of polyresin and liquid crystals is then sandwiched between two pieces of glass forming a (PDLC) panel. The panel is wired to allow a very low voltage to pass through the matrix. When the power is off, the liquid crystal particles are randomly oriented. When visible light passes through the panel, it is randomly reflected and scattered creating a grey translucent fog. When electricity is applied to the panel, the liquid crystal molecules line up in parallel fashion allowing all the light to pass uninterrupted creating a clear transparent window. Varying the amount of voltage varies the amount of light scattered, allowing PDLC panels to have fully adjustable levels of transparency. It is this ability to manipulate and control the intensity of light coming through the panel that is the basis for studying the PDLC panel for its use as a greenhouse glazing.
Why are Cleveland Botanical Garden and Kent State University’s Liquid Crystal Institute collaborating on this project?
Cleveland Botanical Garden (the Garden) and the Liquid Crystal Institute (LCI) are collaborating on this project because both have expertise in different, but essential, aspects of the project. LCI is the leader in liquid crystal research and technology and has the desire, knowledge and resources necessary to adapt liquid crystals for new applications. The Garden, on the other hand, has expertise in growing plants under glass and botanical research. Using an iterative experimental approach the Garden and LCI will provide information to one another in order to develop liquid crystal glazing that will optimize the growing environment. Working together the Garden and LCI could create a fully automated “smart” greenhouse that is easily programmed to provide the ideal growing environment for a wide variety of plants.
What is the potential impact of this research on sustainability practices?
Heating and cooling are the most energy intensive aspects of growing plants under glass. Sunlight, essential for plant growth, also raises the temperature in a greenhouse. High temperatures are both directly detrimental to plant health and increase the amount of water needed by the plant. Shading helps lower greenhouse temperatures, reducing the need for cooling and water, but also affects plant growth, delaying flower development and leading to tall, thin plants. Liquid crystal technology could help a grower maximize plant growth and minimize cooling needs by varying the amount of shading in the greenhouse to optimize the environment inside the green house based on outdoor conditions. For example, the level of shading would be directly related to the intensity of sunlight. Shading would be maximized under mid-day sun, and reduced as the sun moves lower in the sky or when a cloud covers it.
The next generation of liquid crystal greenhouse glazing has the potential to control the wavelength of light as well as the intensity resulting in selective shading. Wavelengths of light that fuel photosynthesis would be allowed through while those more associated with heat (infrared wavelengths) would be shaded. As with the uniform shading described above, selective shading would be variable such that infrared rays could be shaded during summer days, to reduce heat from coming in, and winter nights, to reduce heat from going out. Both uniform and selective shading have the potential to reduce the amount of energy needed to heat and cool greenhouses, making them more sustainable than a traditionally glazed greenhouse.
What is the potential impact of this research on the greenhouse industry?
As energy costs climb and the reliance on fossil fuels becomes less desirable, it is increasingly important to identify advancements in energy efficient greenhouse design and its environmental control systems. For years greenhouse engineers have wrestled with this challenge and have designed various reflective and insulating materials for use on the greenhouse roof in an attempt to keep the excessive heat out during the summer and allow it to enter and remain inside during the winter. However, many of these solutions are often inefficient, temporary, labor intensive and require ongoing manual adjustment to maintain the desired conditions. Liquid crystal panels may provide a cost effective, energy efficient solution for maximizing plant growth and reducing the consumption of fossil fuels.
When will the research begin?
The Garden will be conducting a series of experiments using liquid crystal glass in greenhouse glazing applications. Phase 1 of the research is currently underway and includes project preparation and design of the 8 x 10’ test greenhouses. The greenhouses will be constructed in March 2008 and research data collected throughout 2008 and 2009. Phase 2 will begin in the summer of 2008 as data becomes available. Phase 2 will research and develop the next generation of exterior weather resistant PDLC panels with wavelength governing properties. These panels will control the light spectrum as well as light intensity.
Who are the key players in this research?
Cleveland Botanical Garden:
Natalie Ronayne, executive director, Cleveland Botanical Garden
Mark Druckenbrod, greenhouse research project manager
Dr. Christin DeJong, urban botanist
Brian Casteel, facilities manager
Kent State University Liquid Crystal Institute:
Dr. Oleg Lavrentovich, director, Liquid Crystal Institute
Dr. John West, vice president of Research & Development
Deng-Ke Yang, LCI professor, researcher, inventor