3 strategies to maximize the effect of agricultural lighting

The introduction of intelligent lighting plants which can fill according to the different growth periods, plant, remote, closed, the whole process of intelligent monitoring and operation, the realization of agricultural industrialization, automation, intelligent.

1 intelligent control to promote the new development of agricultural lighting

Although the plants can absorb and use the light with a wide spectral range, but also has a specific spectral response curve. As shown in Figure 1, and visual spectral luminous efficiency curve V (lambda) is similar to that of different plants may have different spectral response curve, can be seen from the figure, in the 400~500 nm between the 1 peaks in the 600~700 nm, there are 1 peaks, it is commonly believed in far red light and blue here it is of positive significance for plant growth.

In recent years some agricultural lighting is not a new thing, the traditional plant growth existed early in the LED before large-scale application, the light source usually adopts xenon lamp, fluorescent lamp, high pressure sodium lamp and metal halide lamp. Although intended to increase the spectral lines in the absorption peak of the plant, but the efficiency is still not high, plant growth light or artificial light plant requires a large amount of lighting electricity consumption, and too much light radiation or light radiation cannot be utilized by plants are a waste of energy.

LED intelligent lighting system to promote the promotion of the two development of agricultural lighting. In recent years, a large number of LED plant growth lamp to the market, careful analysis of the spectral difference is not large, no matter which products are theoretically more efficient than traditional light source system. The classic demonstration project is completed, the flowers and applause but not for last order, reason is that the LED plant growth system cost is too high, how to make ordinary farmers can afford the initial investment, let the promotion of plant growth system of primary agricultural sector's enthusiasm such as the promotion of quality of fertilizer and seeds, and must pay attention to the lighting industry to solve the.

2 improved traditional light source to reduce system costs

LED plant light source usually according to the needs of different plants, using different proportion of blue light and red light and a combination of LED LED. The spectrum is shown in Figure 2, and the dimming mode is reduced or increased by the proportion of red and blue light. The fluorescent lamp is composed of 253.7 nm UV excited phosphor, therefore the initial ratio to determine the spectral distribution, dimming is only proportional dimming, but according to figure 1 photosynthesis curve matching fluorescent powder proportion and dosage, the fluorescent spectrum and the spectrum required for the growth of the plants close, such as the solid line in Figure 2 shown.

Compared with figure 2 and figure 1, it can be found that the spectral distribution of the fluorescent lamp is closer to the spectral response curve of photosynthesis, which is more efficient in theory. In theory, LED can be well matched to plants but the LED spectrum, good monochromaticity and narrow spectrum here become its weakness, only 430 nm blue light and red light of 630 nm can not meet the actual demand but the increase of spectral modulation, some of the other band LED and improve system cost, while the fluorescent spectrum can to a certain extent on broadening, improve the utilization efficiency.

The system efficiency is concerned, the most simple and direct way is to compare the power of radiation, fluorescent light radiation power Figure 2 measured 40.4 W for 11.1 W, the conversion efficiency is 27.5%, the measured 13.4 W LED radiation power is 1.7 W and the conversion efficiency is 12.7%. From the point of view of the optical radiation power, the following table shows that the conversion efficiency of the fluorescent lamp is higher.

The use of previously proposed photosynthetically active radiation flux (PARflux) can more accurately describe plant growth lamp light quality, as shown in (1).

The Bp (lambda) spectral response curve for plant growth, KBp and the corresponding Km is 1, and the normalized correlation photometry parameters, the numerical size and Bp (lambda) on the peak.

At the same time, in order to reflect the influence of photoperiod on the growth of plants, in the actual evaluation of the lighting environment should be the introduction of time parameter t, namely the use of photosynthetic effective radiation dose (PARenergy) characterized by dimensionless equivalent Joule energy (J) as shown in formula (2).

At the same time as the reflected spectrum distribution, illumination time and light intensity of the 3 variables, the type (2) - (3), adapted by light synthesis of effective radiation dose density to authentically express plants in different growth stages for light aggregate. In plant lighting system or can be used as plant growth refinement lighting system of pure artificial light planting in the reference, so as to improve the efficiency of the system.

3 dimming strategy is the core of agricultural intelligent lighting

For remote, closed, the whole process of intelligent plant lighting system, according to equation (3) can be easily variable set, there are 3 variables need to be set, namely P (lambda) plant light spectrum, Bp (lambda) plant spectral response curve, t time. Among them, P (lambda) can be completely solved by the existing technical means, that is, to adjust the spectrum and intensity of plant growth light source, the key lies in the design and adjustment of Bp (lambda) and t.

According to the type of plant can be preset 1 Bp (lambda) initial value, but different growth period Bp (lambda) control and the adjustment of the required exposure time of T according to the actual planting situation is different, can adopt image processing methods were compared with the preset judgment software, can also be through remote online way guided by expert control. The equipment available on the market to build 1 intelligent plant lighting system, as shown in figure 3.