It emits a deep-red light at a wavelength of 660 nanometers, which is perfect for plant photosynthesis. With an efficiency of 37 percent — one of the highest for a light source of this color — it also yields considerable energy savings compared to conventional lamps. In a pilot project in Denmark, which used around 50,000 LEDs to illuminate a cultivation area of several thousand square meters, power consumption in the greenhouse fell by 40 percent.
Relatively little of the light used by plants for their growth is from the visible light spectrum. Chlorophyll molecules mostly absorb deep-red and blue light for the purposes of photosynthesis. Osram Opto Semiconductors has therefore developed an extremely efficient red LED with an emission curve that is very closely matched to the spectral sensitivity of chlorophyll. The new LED is based on the thin-film technology used for high power semiconductor chips.
In greenhouse cultivation, some plants are grown on several levels stacked on top of one another. For this reason, the new LED is available in two variants, each with a different beam angle. The Golden Dragon Plus has a beam angle of 170 degrees and is therefore well suited for use in reflector lamps for illuminating large areas under cultivation. By contrast, the Oslon SSL LED, with a beam angle of 80 degrees, is designed for use in multi-level applications, such as those for the cultivation of lettuce. Using LED light, it is also possible to promote different growth phases of the plant under cultivation. Red light, for example, encourages plants to grow in length, whereas blue light fosters bud formation, for example. Controlled variation of the proportion of blue light between ten and 30 percent reduces use of fertilizer and other chemicals.
Compared to conventional high-pressure sodium lamps, the luminous efficacy of the system as a whole is 60 percent higher with red and blue LEDs. And with a service life of 100,000 hours, the LEDs provide maintenance-free operation for many years. Also involved in the pilot project with Osram were Arrow Electronics and Fiona Lighting A/S, a Danish company specializing in LED lighting for commercial horticulture. Highly efficient LED lighting forms part of the Siemens environmental portfolio, which generated around €28 billion in sales for the company in fiscal year 2010.
Dr. Norbert Aschenbrenner | Siemens InnovationNews
Researchers use light to remotely control curvature of plastics
23.03.2017 | North Carolina State University
TU Graz researchers show that enzyme function inhibits battery ageing
21.03.2017 | Technische Universität Graz
Astronomers from Bonn and Tautenburg in Thuringia (Germany) used the 100-m radio telescope at Effelsberg to observe several galaxy clusters. At the edges of these large accumulations of dark matter, stellar systems (galaxies), hot gas, and charged particles, they found magnetic fields that are exceptionally ordered over distances of many million light years. This makes them the most extended magnetic fields in the universe known so far.
The results will be published on March 22 in the journal „Astronomy & Astrophysics“.
Galaxy clusters are the largest gravitationally bound structures in the universe. With a typical extent of about 10 million light years, i.e. 100 times the...
Researchers at the Goethe University Frankfurt, together with partners from the University of Tübingen in Germany and Queen Mary University as well as Francis Crick Institute from London (UK) have developed a novel technology to decipher the secret ubiquitin code.
Ubiquitin is a small protein that can be linked to other cellular proteins, thereby controlling and modulating their functions. The attachment occurs in many...
In the eternal search for next generation high-efficiency solar cells and LEDs, scientists at Los Alamos National Laboratory and their partners are creating...
Silicon nanosheets are thin, two-dimensional layers with exceptional optoelectronic properties very similar to those of graphene. Albeit, the nanosheets are less stable. Now researchers at the Technical University of Munich (TUM) have, for the first time ever, produced a composite material combining silicon nanosheets and a polymer that is both UV-resistant and easy to process. This brings the scientists a significant step closer to industrial applications like flexible displays and photosensors.
Silicon nanosheets are thin, two-dimensional layers with exceptional optoelectronic properties very similar to those of graphene. Albeit, the nanosheets are...
Enzymes behave differently in a test tube compared with the molecular scrum of a living cell. Chemists from the University of Basel have now been able to simulate these confined natural conditions in artificial vesicles for the first time. As reported in the academic journal Small, the results are offering better insight into the development of nanoreactors and artificial organelles.
Enzymes behave differently in a test tube compared with the molecular scrum of a living cell. Chemists from the University of Basel have now been able to...
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24.03.2017 | Physics and Astronomy
24.03.2017 | Physics and Astronomy