Teach you how to choose the right aquaculture LED lamps

At present, there are few studies on the effects of light on fish growth and reproduction. The use of light sources in aquaculture workshops is simple and extensive, and most breeding plants do not have secondary lighting design when they are built. With the development of semiconductor technology, people gradually realize that LED artificial light as a physical means can not only increase the growth efficiency of aquaculture, but also promote fish growth, control fish gland development, and obtain green high-quality food. LED is a safe and healthy "green light source", no pollution after disposal, environmental protection and energy saving. Nowadays, LED light sources have been used in large scale in plant factories and poultry breeding industries. Aquaculture industry will also increasingly use LED artificial light sources to achieve the functions of aquaculture on-demand production through artificial light environment, significantly improving Production efficiency and efficiency.

Current status of light source in aquaculture production workshop

For a long time, most of the artificial light sources used in aquaculture workshops are straight fluorescent lamps or compact fluorescent lamps commonly used in residential buildings. Fluorescent lamps emit light by using low-pressure mercury vapor to radiate ultraviolet rays during discharge, thereby causing the phosphor to emit visible light. The current advantage of this light source is that it is easy to purchase and easy to install. However, the use of such a light source in the aquaculture industry raises many, if not impossible, problems. First of all, the average life expectancy of this product is about 10,000 hours, but in a humid environment, the life expectancy is only a few thousand hours. Secondly, this kind of gas discharge lamp can't be dimmed, and it can't meet the light demand of fish individuals in different growth stages. Moreover, the disposal of fluorescent lamps can seriously pollute the water source. Studies have shown that the heavier the mercury pollution in the water environment, the higher the mercury content of aquatic animals. Mercury is easily absorbed and enriched by passive objects, and it is not easy to exclude passive objects, and it is not possible to decompose passive objects. It is transmitted through the food chain and can cause harm to the human body. The lamp of an energy-saving lamp contains an average of 2 to 3 mg of mercury. 1 mg of mercury can contaminate 360 ​​tons of water. If the lamp is broken in the culture pond, it will immediately pollute the aquaculture water in the entire workshop. Therefore, the traditional gas discharge source has not adapted to the requirements of environmental protection, energy saving and emission reduction and optimization of optical environment parameters.

Production workshop lighting selection

The chip wavelength, power and electronic control system of the LED luminaire can be determined according to the published literature or the experimentally obtained optimal light environment parameters of the circadian rhythm, feeding behavior, growth and reproduction performance of the fish. At the same time, according to the chip package form, lens light distribution, lamp appearance, and protection level, the whole lamp can be designed, and scientifically applicable LED lamps can be produced and used in the illumination environment of the aquaculture industry.

Where lamps have national, industrial or local standards, they shall comply with the corresponding standards; for special occasions where there is no national, industry or local standard for aquaculture applications, LED lamps shall meet at least the following requirements.

1, the choice of light color, light intensity and photoperiod

Melatonin has a regulatory effect on the hypothalamic-pituitary-gonadal axis of fish. The rhythm of melatonin synthesis and secretion in fish is mainly affected by light and temperature, and fish melatonin is involved in the regulation of reproduction, development and growth. Light, especially the photoperiod, significantly inhibits the synthesis and secretion of melatonin in the pineal gland of fish. The three important factors that artificially create a light environment are light color, light intensity, and photoperiod. Only by giving these three main parameters, the luminaire manufacturer can produce luminaires that meet the requirements.

At present, the main varieties of factory aquaculture are groupers, scorpions, squid, scorpions, squid, squid, black scorpion scorpionfish, pufferfish, American redfish and so on. Each fish grows under unique geographical conditions, including salinity, temperature, water depth, current, oxygen content, nutrient salt, elevation, topographical geology, food resources and food chain structure, as well as historical sea and land changes. In the evolution of wild life in hundreds of millions of years, fish have formed a unique physiological, behavioral, sensory adaptation, etc. The population interacts with the natural environment in the long-term evolutionary adaptation process, so that individuals can choose the fitness light with the greatest fitness. surroundings. For example, the visual pigment of seawater mid-layer fish is suitable for accepting the short spectral band of blue, and most of the visual cells are composed of rod cells. The fish that lay eggs in spring and summer are long-lighted fish, and the fish that lay eggs in autumn and winter are short-light fish.

It has been proved by experiments that by artificially adjusting the light environment, the long-lighted fish will prolong the sunshine time in advance compared with the natural state, and the short-light type fish will shorten the sunshine time in advance than the natural state, which usually enables the fish to mature in advance and spawning. Many studies have shown that this is the case with squid that lay eggs in autumn, that is, the photoperiod has the most obvious effect on fish gonads. Secondly, the factors of light color and light intensity can not be neglected. For example, European cockroaches and larvae reach the optimal development rate under the blue light conditions in line with their wild environment. The best hatching rate (83.9%) was obtained for the Chinese sturgeon at 250 lx. When configuring light color, consider the ratio of rhodopsin to rhodopsin in fish visual pigments, that is, whether the spawning ground is in fresh water or in sea water. The farmer needs to consult the relevant literature and carry out the previous light environment experiment according to the cultured fish species. According to the water depth or habitat characteristics of different types of fish in the natural environment, the required aura value can be roughly estimated, and then the appropriate lamps can be selected. Finally, the experimental data was repeatedly compared at the scene to select the optimal light environment parameters.

2, the secondary light distribution design of the lamp

Aquaculture fish ponds include nursery ponds, adult fish ponds, broodstock ponds, etc. Most of them are cement ponds, plastic ponds or glass fiber reinforced plastic pools. The shapes are round, rectangular, oblong, and ring-shaped. The length of the square fish pond is generally 6 to 7 m, and the pond of the cultured trout is 0.8 to 1.0 m deep. The swimming pools, such as the true carp, the grouper, the American redfish, etc., have a water depth of 1.8 to 2.0 m.

The lens and reflector light distribution method of traditional lamps is basically not suitable for the illumination coverage of aquarium fish ponds. The shape characteristics of circulating water fish ponds are mostly regular geometric shapes, so the lens and reflector of LED should be designed together with high refraction. The rate of the lens material is not only uniform on the surface of the water, but also covers the entire fish pond to save energy. Secondly, according to the different depth of the fish pond water, the luminous intensity of the light source should be considered and scientifically calculated using the formula.

3, protection level safety requirements

The degree of protection should meet the design requirements and comply with GB7000. 5—2007. The humidity of the aquaculture workshop is mostly above 90%, so the waterproof requirements for the lamps are relatively high, and the protection level standard should reach IP65. If the lamps are installed under the aquaculture pond for energy conservation, the IP rating should be at least IP67 or above. The installation position of the lamps in the breeding workshop is easy to contact with people. If the fastening screws touch the live circuit board and other conditions, the electric leakage in the workshop will easily cause electric shock and cause danger. Therefore, when selecting a luminaire, it is necessary to pay attention to whether the protection level IP reaches IP65 or above; the second is to use an isolated constant current power supply, leaving a minimum creepage distance, and it is better to use a centralized external power supply, and the centralized external power supply means A high-power AC / DC switching power supply is used for unified power supply.

4, color temperature and color rendering index

Architectural lighting design must have color temperature (Tc) and color rendering index (Ra) requirements. The color temperature is represented by Tc and the unit is K. When the radiation of the light source is exactly the same in the visible region and the absolute black body, the temperature of the black body is called the color temperature of the light source. The red radiation of the low color temperature source is relatively more, and the proportion of blue radiation increases after the color temperature is increased.

The color rendering index is expressed by Ra, and the color rendering index is an original color indicator of the substance. The higher the color rendering index, the closer to the original color of the substance, the value is close to 100, and the color rendering is best. In aquaculture production, these two light source indicators are generally not required. However, when a long-wavelength spectral energy distribution is required, the R9 saturated red ratio in the CIE-defined CRI can be increased, that is, the nitride red phosphor in the package is increased; when a short-wavelength spectral energy distribution is required, a white light source having a higher color temperature can be used. . Therefore, in some cases, long-wavelength monochromatic light can be replaced by white light having a low color temperature and a high color rendering index, and a short wavelength can be replaced by white light having a higher color temperature. The advantages of this design are as follows: First, white light is very beneficial to the visual health of the workshop operators; second, white light is used for functional lighting, and the cost of purchasing equipment in the breeding industry can be greatly reduced.

5, the switch of the lamp

Instantly turning on and off the lighting fixtures can cause stress reactions on fish such as Atlantic salmon, puffer fish, and grouper, as well as shrimp. When fish and shrimp are in an emergency response state, stress hormones are released, blood and tissue components change, respiratory rate and heart rate change, and immune levels decrease, leading to susceptible diseases and parasites, which are not only affected by reproductive growth, but also severely increased. rate. Therefore, the switch should be gradually brightened and gradually extinguished to eliminate the light stress on the fish. To solve this problem, LED intelligent control is required. One of the solutions considered now is to implement the real-time clock RTC and PWM waveform output by the microprocessor MCU. The RTC can be accurate to the second, and the user can set the gradient interval by himself; the brightness adjustment of the LED is achieved by adjusting the duty cycle of the PWM waveform. The duty cycle can be graded, and can generally be divided into 0 to 100 levels. This gradual change will effectively prevent the instantaneous opening and closing of the LED light source to produce a stress response to fish and shrimp.

in conclusion

The factory farming workshop is different from the natural environment and requires artificial lighting. In general, full light and full darkness are detrimental to fish growth and development. The light environment is only an important factor affecting the behavior of fish, and it should be configured together with factors such as temperature, water quality and bait. At present, there are few studies on aquaculture related to light environmental factors in China, and the illumination of the breeding workshop and the installation of lamps are more extensive and random. With the development of semiconductor technology, people have gradually realized that LED light source as a physical means can better increase aquaculture production efficiency and obtain large-scale, green and high-quality fish products. If it is possible to determine the illumination parameters affecting the circadian rhythm, feeding behavior and reproductive performance of a certain fish, a suitable LED light source can be used to make a comprehensive technical and economic analysis according to the relevant national standards and according to the efficiency, life and price of the lamps. It correctly creates a light environment suitable for aquaculture requirements, so as to promote the LED light source to play a greater role in the factory efficient aquaculture industry.