Road lighting environmental protection research

Discussion on energy saving of road lighting

1 Optimize the luminaire design to improve the efficiency of the whole lamp. The energy-saving luminaire includes all the components needed to fix and protect the light source except the light source, and the line accessories necessary for connecting with the light source. The National Energy Certification Center issued the road lighting system energy-saving certification technical specifications (CQC 3105-2009) put forward the requirements for lighting energy-saving certification. Selecting lamps with good light distribution, high reflectivity and low maintenance workload can reduce the number of lamps and power loss on the basis of the same lighting quality, thus saving energy. According to the requirements of the Green Lighting Project Planning Outline of the Eleventh Five-Year Plan of the Ministry of Construction, by 2010, the application rate of high-efficiency energy-saving lamps with luminaire efficiency above 80% will reach more than 85%. At present, the efficiency of domestic lamps is uneven, and it can reach more than 80%.

The efficiency of the luminaire has a close relationship with the reflectivity and light distribution characteristics of the reflector, the light transmission performance of the lampshade, and the protective performance.

1 1 Design efficient, light-distributing reflector

The reflector is the core component of the luminaire. Its function is to reasonably distribute the luminous flux of the light source to meet the light distribution requirements of the environment (road) and the working surface without glare and severe light curtain reflection. The optical design of the reflector is very important. Its material and shape determine the output efficiency of the luminaire. Reasonable light distribution is beneficial to improve the average brightness of the road surface, ensuring uniformity of illumination and limiting glare to meet the standard requirements. .

At present, the road lamps and lanterns designed in China are limited by the technical level. Generally, they only pay attention to the appearance and shape, but the emphasis on the design of the reflector is not enough. The lack of research is just a copy of the imitation. It is not only unreasonable in light distribution, but also inefficient and wastes energy. This is in stark contrast to the elaborate design of foreign lighting manufacturers on the reflectors, which has become a bottleneck that hinders the development of the domestic road lighting industry.

In the face of high-end users at home and abroad, CLP Panda's lighting products began to realize the extreme importance of the performance of the reflector, and began to special research on the reflector, and achieved some results. The optical inspection data of the road luminaire reflector developed by the company at the National Lamp Quality Inspection Center is provided below. 1 is the optical curve of a road lighting fixture (400 W high pressure sodium lamp)

(1) The luminaire efficiency is 81 3%; (2) The light distribution curve: the cut-off type, the wing-shaped light distribution, the maximum light intensity angle is 57 5 , and the ratio of the maximum light intensity value to the light intensity value under the lamp is 2 5 The light distribution curve is uniform.

(3) Utilization coefficient curve: When the luminaire is installed with an elevation angle of 15 and the height ratio is 2, the utilization of the roadside light is 54%, and the light utilization rate of the house is 21%.

(4) Plane illuminance curve: light intensity is slowed down, light distribution is uniform, total uniformity and longitudinal uniformity are good.

The actual use effect shows that the illuminator of the luminaire has excellent illumination performance, which is 5% 10% higher than that of the general luminaire. Therefore, in the promotion of lighting energy saving work, it is very important to design a luminaire reflector with high efficiency and reasonable light distribution. American Lighting Technology Co., Ltd. (LT I) PHOT OPIA optical design software, suitable for the design of non-imaging optical systems in the geometry of reflectors. The design software has a database of various light source and reflector application materials for design and application.

The software can simulate the optical parameters of the reflector, analyze the traces of light emitted from various points on the light source and the distribution of the reflected light after multiple reflectors, and then combine the direct and reflected light to obtain the light distribution. Curve and reflection efficiency for reference when design improvements.

Most of the road lamps use high-pressure sodium lamps and metal halide lamps, which have higher power and higher heat generation, so the size and surface area of ​​the reflector will affect the heat dissipation of the light source. If the volume is too small, the heat dissipation will affect the service life of the light source and the optical performance of the lamp. At the same time, it will affect the color temperature and color rendering of the light source, affecting the lighting effect in places with high light color requirements. Therefore, the American Idea can be used in the thermodynamic design. s, pro e computer software, to help predict and analyze the temperature distribution of the lamp to avoid adverse consequences.

1 2 New materials and new processes are adopted to improve the surface reflection coefficient of the reflector. There are many kinds of materials for the reflector, such as ordinary aluminum plate (polishing), high-purity aluminum plate (electrochemical polishing), surface sandblasted aluminum plate, stainless steel plate, etc. The pure aluminum plate has the best reflection coefficient. It can be said that lamps of the same power and the same light source use different material reflectors, and the illumination and uniformity generated on the ground are completely different. Most of the street light reflectors are made of high-purity aluminum sheets by stretching and stamping. The surface is chemically polished and anodized. The thickness of the oxide film is 7 8 m, and the surface of the oxide layer is treated by steaming water or pure water sealing. When the purity of aluminum is 99 6%, the reflection coefficient is about 0 76 0 78; when the purity of aluminum is 99 7%, the reflection coefficient is about 0 80; when the purity of aluminum is 99 8%, the reflection coefficient is about 0 82; the purity of aluminum is 99 9%. When the reflection coefficient is about 0 85. When the oxide film is thin, the reflection coefficient is high, but its corrosion resistance is poor. Therefore, it is very important to determine the appropriate oxide film thickness and the purity of the aluminum plate.

To further improve the reflective coefficient of the reflector, vacuum coating of the multilayer dielectric film technology can be employed. The surface of the metal reflector is first coated with a high temperature resistant plastic resin as a substrate, and then vacuum coating technology is used to alternately apply low-order light TiO2 and high-order light SiO2 to the 1721 layer to obtain a high temperature resistant hard film, reflecting visible light. , transmission infrared, the composite film has a reflection coefficient greater than 0 94, good specular characteristics, can greatly improve the optical performance and efficiency of the reflector.

A new process for the sealing of aluminum reflectors and nano-composite oxidation is being recognized and accepted by leading-edge street lamp manufacturers.

It is added with sub-nanometer fine powder SiC or A l2O3 in the anodizing process of aluminum reflector, so that the porosity of the oxide film is decreased, the film formation rate is improved, and the film has high hardness, good corrosion resistance and high temperature resistance. It protects the accuracy and roughness of the reflector surface. The composite alumina film also has a certain absorption effect on infrared rays.

The reflector of the tunnel lighting fixture can be made of high-purity mirror aluminum plate processed by the rolling process, and the reflectivity is 92%, which is about 8% higher than that of the high-purity aluminum plate.

1 3 lampshade with high transmittance material

The effect of the transmittance of the transparent lampshade on the overall lamp efficiency is self-evident. Its materials and processing technology have undergone great evolution in the past decade, and its performance characteristics and application age are roughly divided as shown in Figure 1.

1 Road lighting fixtures with transparent lampshade material lampshade material light transmittance / % production process and method performance characteristics 60 milk glass transparent frosted glass 60 65 artificial blown anti-corrosion, good weather resistance, low cost, low light transmittance, easy to break The wall thickness is uneven.

70 transparent glass 86 88 artificial blown anti-corrosion, good weather resistance, low cost, high light transmittance, easy to break, uneven wall thickness.

Transparent glass hard borosilicate glass 82 85 molded light is refracted by prism, soft light, high strength and not easy to break, high price 80 high temperature resistant plexiglass plate 88 molding + air pressure high transmittance, light weight, uniform wall thickness. Poor weatherability, brittleness, temperature resistance 105 (not enough).

90 Polycarbonate (PC) 88 89 Injection molding has good weather resistance, temperature resistance of 128 (higher), impact resistance and non-breaking. The price is high, and the surface is electrostatically adsorbed and accumulated, which affects the light transmittance.

Nowadays, the floating borosilicate glass plate 90 is molded and heated to form a uniform wall thickness, safely tempered, high in light transmittance and suitable in price.

After a long period of time, the road lighting fixture will form a dust-dust phase dust film on the surface of the lampshade, which will hinder the transmission of light, causing the illumination to drop by 10% and 20%. Therefore, cleaning the dust on the surface of the lamp regularly is a common way to improve the light maintenance rate. The method, but it is not easy or realistic to do this in real life, so how to take an effective measure to reduce the rate at which soot and dust accumulate on the surface of the transparent cover is a good method with practical significance. Here, a method is described in which a film of TiO 2 is coated on the surface of a transparent lampshade, and the film undergoes a photochemical reaction after being exposed to light, and combines with an organic bond (CH) in the oil vapor on the surface of the glass to form CO 2 and H 2 O. The surface has a water protective film. Because of the good hydrophilic properties of CO 2 , soot and dust are easily washed away by rain, and the surface of the lamp cover is always kept clean and maintains good light transmittance.

1 4 Improve the protection level of the reflector system

The sealing performance of the luminaire is an important factor that directly affects the maintenance rate of the light output. The sealing performance is poor, the light source chamber is easily contaminated, the reflection coefficient of the reflector surface is lowered, and the whole lamp efficiency is drastically reduced. According to the actual situation in China, the protection level of the light source room of the luminaire must reach IP65. The light source room is sealed, that is, the reflector is sealed with the transparent lamp cover and the push-pull lamp holder. The temperature and weather resistance silicon can be used between the sealing surfaces. The rubber sealing strip or neutral silica gel is directly bonded, and the protection level of the whole lamp usually needs to reach IP43.

1 5 using a respirator to delay light attenuation

In the process of the light source switch, the temperature change in the light source chamber will cause the change of the thermal expansion and contraction of the air, forming a "breathing" phenomenon, that is, the air pressure of the light source chamber needs to rise outward when the light is turned on; the indoor expansion after the light is turned off The air will reduce the volume to form a negative pressure, causing the seal to contradict the hot and cold air exchange. The solution to this contradiction is to install an activated carbon air filter in the light source chamber to convect the air, because the activated carbon has a high-density surface area, the adsorption value to water vapor and organic vapor is 25% or more, and the iodine adsorption value is greater than or equal to 900 mg / g, pH 4 11, can effectively block the polluted air, filter it into the light source room, protect the light source and reflector from contamination, thus delaying the light attenuation.

2Using energy-efficient light source appliances to save energy

2 1 using high luminous efficiency light source

High-pressure sodium lamps and metal halide lamps are the main high-efficiency lighting products in high-pressure gas discharge lamps (HID).

The high-pressure sodium lamp is characterized by a long life of 24,000 h, a high luminous efficiency of 100 120 lm / W, and strong fog permeability. It can be widely used in road lighting, floodlighting, square lighting, etc., and replaces high-pressure mercury lamps with high-pressure sodium lamps. Under the same illumination, it can save 37%. The enhanced high-efficiency high-pressure sodium lamp has higher luminous efficiency and longer life. Taking 250 W as an example, the enhanced light efficiency is increased from 112 lm/W to 128 lm/W compared to the original normal type; the luminous flux is increased from 28000 lm to 33200 lm; the lifetime is increased from 24000 h to 32000 h. In actual use In the middle, the average brightness is increased by 14 2% and the life is extended by 33 3%. When using high-pressure sodium lamp products, the energy efficiency value should meet the requirements of GB19573-2004 high-pressure sodium lamp energy efficiency limit value and energy efficiency rating.

A metal halide lamp is a high-pressure gas discharge lamp in which a metal halide is added to a discharge tube to cause a metal atom or a molecule to participate in discharge and emit light, which is characterized by a long life (8000 20000 h) and light. High efficiency (75 95 lm / W), good color rendering, widely used in industrial lighting, urban lighting engineering lighting, commercial lighting, stadium lighting, etc., to replace high-pressure mercury lamps, under the same illumination conditions, Saving electricity by 30%.

LED (Light Emitting Diode), also known as LED, uses a solid semiconductor chip as a luminescent material. When a forward voltage is applied to both ends, carriers in the semiconductor recombine, releasing excess energy and causing photon emission to generate visible light. The advantages of LED are long life maintenance, small energy saving, low power consumption, energy saving, good directionality to avoid light pollution, small size, easy to hide lamps, fast response, easy to control changes, etc., which are widely used in landscape lighting. From point sources, MN belts, to digital light pipes, buried lights, and spotlights cover almost all areas of traditional light sources. Due to its energy-saving and energy-saving features, LEDs are increasingly being combined with solar installations to form the most energy-efficient and environmentally-friendly lighting facilities.

2 2 Energy-saving magnetic ballasts, variable rate ballasts and electronic ballasts

High-efficiency light source street lamps such as high-pressure sodium lamps and metal halide lamps. In addition to the energy consumption of the light source itself, the loss of the magnetic ballast accounts for 10% of the power of the light source. 16%. According to the requirements of the Green Lighting Project Planning Outline of the Eleventh Five-Year Plan of the Ministry of Construction, high voltage The energy efficiency index factor (BEF) of the sodium lamp ballast meets or exceeds the GB19574 2004 ballast energy efficiency limit value and energy conservation evaluation value standard. A large number of domestic magnetic ballasts are still traditional old products, and their performance is stable and cheap, but the power loss is large. Starting from China's national conditions, if the traditional magnetic ballast is updated to energy-saving, it will achieve considerable energy-saving effects.

The variable power inductor ballast utilizes the principle that the gas discharge lamp can still operate normally when the working current is appropriately reduced, and the power is automatically adjusted according to the change rule of the traffic flow. In the midnight of the vehicle shortage, the time-limited system of the preset circuit is pressed. The set time automatically converts the power, so that the HID lamp can run at a rated power of about 60% to meet the requirements of basic road lighting. The power consumption is reduced by 50% compared with the traditional ballast, the system energy efficiency is more than 30%, and the service life is more than 10 years. . For the original road lighting project, additional variable power ballasts can also be used for retrofitting, and the ballasts of the original lamps are not replaced, which is convenient for reconstruction and reduces the cost of system renovation.

2 3 use electronic ballast to regulate energy saving

The electronic ballast has the advantages of high efficiency, high power factor, no stroboscopic, no noise and energy saving. The electronic ballast can replace the traditional magnetic ballast to save 20% 30%. The electronic ballast is constant power output. It can automatically control when the power supply voltage fluctuates, protect the stability of the light, prevent the light source from working at high voltage under high voltage, and self-extinguish at low voltage, which is especially beneficial when the current grid voltage is generally high. The working current is 60% smaller than the magnetic ballast, the power consumption is low, the power saving is 30%. The power factor is 0 98, which is beneficial to ensure the life of the light source. When the line is short-circuited or broken, it can automatically cut off the power; It can automatically resume work after troubleshooting. However, due to the temperature rise of the electronic device itself, the high-power HID electronic ballast has unstable operation reliability, long life and high price, which is not conducive to popularization and application. The National Development and Reform Commission has listed electronic ballasts as "energy-saving." Focus areas and key projects", are applying micro-nano technology - nano-silicon CM OS devices and nano-circuit system design, to explore and solve the above problems, I believe that it will not be too long, reliable electronic ballasts will be universally applicable.

In the case where the voltage fluctuation is large, or when the power supply voltage is too high, that is, when the voltage of the lighting fixture exceeds 90% of the rated voltage, the device with voltage regulation and voltage regulation function is used.

This type of device collects the input voltage signal in real time and compares it with the set output voltage. Through the thyristor chopper, auto-coupled buck and microcomputer control, it detects, analyzes and calculates to find the best power point. Dynamically adjust the output voltage, improve the power factor of the lighting power system and balance the three-phase voltage output, stabilize the working voltage, save energy and protect the lamps. This kind of energy-saving mode is suitable for the occasion where the power supply voltage is high, and the adjustment range should also be moderate, otherwise it will affect the normal operation of the street lamp. The power saving rate is generally 10% and 20%, but the initial investment is high, and the volume is large, and the installation position is limited.

2 4 using compensation capacitor

The light source of reactive power compensation is mainly a gas discharge lamp, which has a large starting current and a low power factor, and is generally below 0 45, which causes a large loop current and a large loss on the line. The urban road lighting design standard requires that the gas discharge lamp should be compensated by the capacitor. The power factor after compensation should be no less than 0. 8. However, the standard does not specify whether it is concentrated compensation or single lamp dispersion compensation. Currently, two types of capacitor compensation methods are used. The author believes that since the streetlight facilities are evenly distributed on both sides of the road, the low-voltage wiring from the power supply to the streetlights is long, and the loss caused by the road lighting system mainly occurs in this section. The centralized compensation method of the streetlight power supply cannot reduce the low voltage. Power consumption of wiring. The use of single lamp dispersion compensation can undoubtedly reduce the loss generated by the street lamp power supply to the lamp, which will have a good power saving effect.

Single-lamp capacitor reactive compensation is to use a capacitor of suitable capacitance in parallel with an inductive load (inductive ballast) to achieve a power factor of 0 85 0 9, to reduce reactive power in the lighting circuit and reduce the voltage on the lighting line. And power loss, reducing line current nearly 50%, has a very far-reaching significance for saving energy, can also reduce the wire cross-section, saving investment in wiring engineering. The compensation capacitor value is commonly used for high pressure sodium lamps.

3 end

It should be emphasized that road lighting fixtures must achieve satisfactory results and are also related to the rational arrangement of the lamps. Lighting design is particularly important. The layout of the luminaire should consider the installation height of the luminaire, the length of the extension of the luminaire, the elevation angle of the luminaire, the spacing of the poles and other factors. American Lighting Technology Co., Ltd. (LT I) Simple lighting design software can introduce the optical parameters of road lighting fixtures, and adjust the above parameters to simulate the road lighting effect, which can guide the lighting design.

In the current environment of building a resource-saving society, the design of any product cannot ignore the design of energy-saving. In the case of full competition in the market, only products that are safe and reliable, have excellent performance, and are energy-saving can have vitality.

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