Tuesday, November 20, 2012


With green house facilities becoming important for producing many plants of economic importance. billions of dollars are being invested world over in establishing huge facilities, especially for high value plant crops including herbs. Since sun light is available only for limited time each day, it was but logical for the green house set ups to use artificial lighting using electricity. During the last few years the lighting industry has seen a dramatic shift from incandescent lighting to LED system because of many positive reasons, the most important benefit being energy saving. World over there are concerted efforts to wean away energy consumers from traditional light sources to LED system through a variety of incentives. The percolating effect of LED lighting has touched the green house facilities also and thanks to recent innovations, LED lighting in green house plant production facilities have been found to have dramatic advantages, especially in terms of energy saving and improved plant growth benefits. Here is a take on this new development which may revolutionize the economics of green house production system in coming years.

"Traditional growth chambers use power-hungry fluorescent and incandescent lighting or high-pressure sodium and metal-halide. Bulbs often have to be replaced yearly at a high cost. The excess heat from these less-efficient sources has to be removed from the chamber by built-in compressors, and research data was often lost if this equipment turned off for even an hour. Industrial light sources for growth chambers are pretty standardized, and this study examined a totally new approach. The experimental protocol was straightforward. The team retrofitted a growth chamber with LED lighting and ran growth tests with a second "stock" chamber as a control. All aspects of the chamber performance were evaluated, including electricity, heat, cooling, watering, humidity, maintenance and plant growth. The team anticipated and found great potential savings for both Penn State operations and research. LEDs not only provided substantial lighting savings but also reduced the need for compressor cooling, associated maintenance and watering. Since the chamber lighting runs cooler, there is less evaporation and less stress on the plants. LEDs also will last five to 10 years and need far fewer replacements than the old high-intensity fluorescent and incandescent bulbs. Even though plants evolved in full sunlight, they don't actually utilize all the wavelengths that sunlight provides. Depending on the plant species, they like blue, medium-red and far-red wavelengths. LEDs can focus the spectrum energy and intensity where it is most beneficial to plant growth. Conventional lighting provides a full spectrum and generates a lot of excess heat, especially in a small growth chamber. Since LEDs can supply only the wavelengths needed, the excess heat is minimized. Additionally, LEDs are ideal for research purposes because each wavelength can be controlled independently".

The debate about the economics of LED lighting system is still going on with the consumers resisting large scale adoption because of the fact that LED bulbs are far more expensive than the conventional incandescent or CLF counterparts. But technological break through happening at a frenetic pace can certainly bring down the cost dramatically within this decade. As far as its use for green house gardens, the cost may not be a barrier considering the enormous versatility inherent in using LED technology. If the results are confirmed, LED lighting may find faster use in the agriculture sector than at domestic level.


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