| The high-energy consumption of plant factory is the biggest issue for its rapidly expanding,lighting electricity consumption accounted for the largest. Light-emitting diodes(LED) gradually be researched in plant factory as an electricity-efficient light source both at home and abroad. However,LED merely solve the high energy consumption of equipment,the type of light in plant factory is still scattering, the emission angle is 180°. Most of the light ray scatters to the cultivated space where no plants are,the optical energy were not utilized by plants. The efficiency for light energy utilization was still at a low. The new way of lighting type what has more effective is of great significance to plant factory. An optical system applied just below LED was designed. The optical block is consist of multi-LED,convex lenses and Fresnel lenses,which can focus the light and form an orbicular spectrum spots. According to the size of plants,we adjust the size of spectrum spot and achieve the goal of improving light distribution. The effects of the light system on growth and photosynthesis of butterhead lettuce(Lactuca sativa L.) were examined,and the performances of the light system on energy saving was evaluated by comparison with the traditional LED illumination system. The experimental results showed that:(1)Adjustable orbicular spectrum spots LED consist of convex lenses and Fresnel lenses,put the light together to improve the light distribution. Through the theoretical energy saving calculation,the minimum energy saving value is 41.2%. The system has a high value of researching.(2)The test system has remarkable energy saving effect: The electricity consumption of new type light source reduced 52.06%. Meanwhile,the light use efficiency(LUE) increased 55.64%. As well as,the photosynthetic parameters are also significantly decreased as the plant yield. Nevertheless,the morphological parameters(leaf length, leaf width,leaf number,leaf area) have no significant difference between the two lighting system.(3)The influence of leaf temperature,solution temperature and the temperature of plant cultivation between the two lighting system: On account of improving the LED output power,the light that was focus can significantly increase leaf temperature and nutrient solution temperature,which can raise 1 ℃ and 2 ℃ respectively. At the same time,due to the cultivation of plate of the test system was not below light ray,its temperature of cultivation blank temperature has been at a stable state of relatively low level. Temperature has certain influence on photosynthesis,physiological and biochemical index of lettuce cultivation.(4) The author introduced industrial machine vision and computer control technology,combined with adjustable orbicular spectrum spots LED lighting source,built the accurate lighting system,realized the lettuce planting daily monitoring and changed light spot with intelligent controlling daily. The new type LED lighting system change the distribution of light ray,and the light energy saving effect is obvious. We raise a new idea which is focused irradiation. The multi-LED, convex lens and Fresnel lens were employed in the new LED lighting system. It can change light emission angle and achieve electricity saving. The precision lighting system also provided technical support for the development of intelligent control technology in plant factory. |
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