Construction of environmentally friendly street lamps in a new university in Tianjin

According to a special survey conducted by the China Green Lighting Project Promotion Project Office, China's lighting power consumption is more than 300 billion kWh per year. By replacing all incandescent lamps with LEDs or partially replacing fluorescent lamps, it can save 1/3 of lighting power, which means It can save 100 billion kilowatt hours of electricity. LED as an emerging industry, China's LED market will reach 150 billion yuan in 2010. LEDs are used in a wide range of applications, including communications, automotive, lighting, and signal lights. In recent years, the LED light efficiency and high-power integration technology have been greatly improved, laying a foundation for the large-scale application of high-power LED in the field of lighting.

The 1300-inch, 40-W semiconductor energy-saving street lamps (LEDs), which were built in the new campus of Tianjin Polytechnic University, have been successfully applied. Its main functions and parameters are as follows: Use: Main road lighting; Input voltage: 180V-260V; Total power: 50W; Output luminous flux: 1600lm; Color temperature: 5500K; Color rendering index: >85; Uniformity: 0.4; Service life: 3000 In hours, the light decay is less than 15%.

The engineering scheme selects high-power LED as the light source, solves the problems of the street lamp in terms of optics, heat dissipation, power supply and drive circuit and reliability design, and formulates the production process and inspection and maintenance plan of the semiconductor street lamp. The first phase of the semiconductor lighting demonstration project of the new campus of Tianjin Polytechnic University, designed and produced two kinds of high-power â–¡ Tianjin University of Technology Information and Communication Engineering Mao Borian Niu Pingjuan Guo Yixiang â–¡ British Thorn Lighting Tianjin Yuan Jingyu's new semiconductor energy-saving street lamps, respectively 40W, 20W, of which 40W street lamps are used for trunk road lighting, and 20W street lamps are used for trunk road auxiliary road lighting. The input voltage of the luminaire design is 220V. The luminous output of the three street lamps is 1600lm and 800lm respectively. The method of double-sided lighting is adopted. The distance between the poles is 25 meters, the height of the pole is 7 meters, and the inclination of the lamp head is 15 degrees. The main structure of the luminaire consists of three parts, the light source, the power supply and the heat sink.

The semiconductor light source belongs to a point light source, and the light divergence angle is generally between 120 degrees and 140 degrees. Therefore, the secondary optical design of the semiconductor street lamp is required.

The project adjusts the light distribution of the semiconductor street lamp by two methods: 1. Adjusting the main optical axis angle of each sub-light source in the semiconductor street light source.

2. Strengthen the light intensity on both sides of the semiconductor street light source by adding a reflector cup. After these two measures, the light distribution of the new semiconductor energy-saving street light source has been greatly improved. LED driver generally adopts two methods: constant voltage driving mode and constant current driving mode. Since the driving method of constant voltage is relatively simple, the previous LED light source adopts constant voltage mode. By comparison, it is found that the voltage of the LED and its relative luminous flux are also exponential. Therefore, the constant current driving method can stabilize the light output of the LED more than the constant voltage driving method. Therefore, the constant current drive method was chosen. Therefore, the constant current power supply is used to supply 10W LEDs, and the LED constant current

1. Exterior lighting of buildings. Projecting a certain area of ​​the building is nothing more than using a round head and a square-headed floodlight that controls the beam angle, which is exactly the same as the traditional floodlighting concept. However, due to the small and thin LED light source, the development of linear projection lamps has undoubtedly become a highlight of LED projection lamps. It is easy to install, can be installed vertically, better integrated with the building's surface, and has an impact on the lighting of modern and historic buildings.

2. Landscape lighting. Since LEDs are not glass bulbs like traditional luminaires, they can be well integrated with cities and streets. It can be illuminated in the city's leisure spaces such as paths, stairs, decks, waterfronts, and gardening. For flowers or low shrubs, LEDs can be used as a light source for illumination. LED recessed floodlights are particularly popular. The fixed end can be designed as a plug-in type, which is easy to adjust depending on the height of the plant.

3. Marking and indicative lighting. Spaces where space limitation and guidance are required, such as separation display of road pavement, local illumination of stair steps, and indication lighting of emergency exits, LED self-illuminating buried lights with appropriate surface brightness or lamps embedded in vertical wall surfaces, such as The ground guide light in the auditorium of the theater or the indicator light on the side of the seat, and the guide light on the floor inside the shopping mall. In addition, compared with neon lights, LEDs are low-pressure, have no fragile glass, and do not increase the cost due to bending during production. It is worthy of being promoted in logo design.

4, indoor space display lighting. As far as the lighting quality is concerned, since the LED light source has no heat, ultraviolet and infrared radiation, it does not cause damage to the exhibit or the product. Compared with the conventional light source, the lamp does not need an additional filter device, the lighting system is simple, the cost is low, and the installation is easy. Its precise lighting can be used as a substitute for museum fiber optic lighting. The commercial lighting metropolis uses colored LEDs, and the interior white LEDs combined with the interior decoration provide auxiliary lighting for the interior.

The power supply is made by the principle of PWM switching power supply. The power supply product should be aging for 24 hours before leaving the factory. The waterproof rating: IP66 standard requires encapsulation of epoxy resin. LED is a kind of semiconductor solid-state light source. Its performance and lifetime are inversely related to the operating junction temperature of the semiconductor light source. Therefore, the semiconductor light source needs a good heat dissipation design. The main method is to dissipate this heat to the external environment through the heat sink. The street lamp works outdoors, and the outdoor lighting conditions require good airtightness to ensure the normal operation of the internal light source and electrical appliances of the street lamp. This airtightness affects the heat dissipation of the semiconductor light source, thus affecting the energy saving of the semiconductor. The performance of street lights. Therefore, a new overall heat dissipation structure is proposed in this solution, which solves this problem well. It will not damage the sealing characteristics of the lamp housing, and can achieve good heat dissipation effect. Actually, in the environment of 35 degrees and no convection, the junction temperature of the LED is less than 75 degrees, which meets the design requirements.

In summary, this paper designs a new type of semiconductor energy-saving street lamp, which uses the advantages of energy saving, environmental protection and safety of semiconductor lighting source to produce a high-efficiency, green and long-life lighting device. It has very important practical significance. The use of semiconductor lighting devices to replace traditional lighting devices, its advantages: first, improve energy efficiency, save a lot of lighting power; second, reduce the use of various toxic heavy metals needed to manufacture traditional light sources, protect the environment; third, white light The illumination of LED street lamps is better for identifying objects such as plants and faces, and the color reproduction is true. Fourth, it has accumulated knowledge and experience for the development of semiconductor lighting fixtures in the future.

Compared with the traditional energy-saving light source sodium lamp and metal halide lamp used in the current street lamp, the LED has high safety. The low-voltage power supply is used, and the power supply voltage is between 6-24V, which is especially suitable for public places, and the LED is small in size and strong in appearance. It is also resistant to vibration and can be prepared into various shapes of light-emitting devices for a wide range of applications.