Electric light source refers to light-emitting devices, such as bulbs and tubes, electrical wires, lamp holders, sockets, lampshades, compensators, controllers, etc.
Lighting energy saving is directly related to the selection, installation and use of the whole lighting fixture. Here, we focus on the electric light source, which is the main equipment for lighting energy saving.
There are two conversion mechanisms of lighting electric light source: thermal radiation light source and gas discharge light source.
4. Application of thermal radiation light source
Thermal radiation light source refers to an electric light source that emits light by heating the filament to the degree of incandescent lamp through current.
(1) incandescent lamp. Ordinary incandescent lamp is the earliest and most widely used electric light source and the most common lighting appliance.
Ordinary incandescent lamp is the most widely used lamp because of its small size, low price and convenient use. Incandescent lamps, on the other hand, have low energy conversion efficiency, most of which is converted into infrared radiation and lost, and there is not much visible light. Moreover, the life of incandescent lamps is generally only about 1000 hours.
Compared with ordinary incandescent lamps, white coated incandescent lamps, krypton lamps and infrared reflective film incandescent lamps developed in recent years have greatly improved their luminous efficiency and service life. White incandescent lamp is coated with white inorganic powder on the glass shell of the bulb, which improves the luminous efficiency by 5% compared with ordinary incandescent lamp and is softer and more comfortable than ordinary incandescent lamp. Krypton incandescent lamp uses krypton with low thermal conductivity instead of argon, nitrogen and other inert gases in ordinary incandescent lamp as filling gas, which can reduce the heat loss and vaporization rate of filament, improve luminous efficiency 10% and double the service life. An incandescent lamp with infrared reflection film is characterized in that a transparent infrared reflection film is coated on the glass surface of the bulb, and then infrared rays are reflected back, so that the temperature of the filament can be increased, the luminous efficiency can be improved, and more than 1/3 of electricity can be saved. These new incandescent lamps are gradually replacing ordinary incandescent lamps.
(2) Tungsten halogen lamps. Tungsten halogen lamp is an improved incandescent lamp with a certain proportion of halide in the bulb. When ordinary incandescent lamps are used, the tungsten evaporated from the filament is deposited on the inner wall of the bulb, which leads to the blackening of the glass shell, the gradual decrease of light transmittance and luminous efficiency, and also reduces the service life of the tungsten filament. In addition to filling inert gas into the bulb, the halogen tungsten lamp filament also fills a small amount of halogen photochromic substances, such as fluorine, chlorine, bromine, iodine or their corresponding halides, so as to form the cycle process of the halogen tungsten lamp in the bulb, prevent tungsten from depositing on the glass inner shell and slow down the aging speed of the filament. The luminous efficiency of tungsten halogen lamp is about 30% higher than that of ordinary incandescent lamp, and its service life is about 3 times that of ordinary incandescent lamp. It has been widely used in public buildings, transportation and film and television lighting.
Application of gas discharge light source
Gas discharge light source is an electric light source whose electrode emits light through one or more gases or metal vapors under the action of electric field. The arc of gas discharge light source has negative volt-ampere characteristics, that is, the greater the electro-light, the smaller the voltage. In order to make the lamp work stably, a rectifier is installed on the circuit, which consumes both active power and reactive power, and electrical accessories such as up-converter are installed for starting the lamp.
There are many kinds of gas power generation light sources, which can be divided into two categories according to the inflation pressure: one is high-pressure gas discharge lamp, and the other is high-low pressure gas discharge lamp.
High pressure gas discharge lamps are mainly high pressure mercury lamps and high pressure sodium lamps, among which fluorescent high pressure mercury lamps and metal tungsten halide lamps are the most widely used.
Low-pressure gas discharge lamps mainly include fluorescent lamps and low-pressure sodium lamps, and the most commonly used fluorescent lamps include straight tube type, ring tube type and compact fluorescent lamps. Gas discharge light source is much more efficient than thermal radiation light source, so it is widely used.
(1) fluorescent lamp. Fluorescent lamp is an electric light source that uses ultraviolet rays generated by low-pressure mercury vapor discharge to excite fluorescent powder coated on the inner wall of the lamp tube and convert it into visible light, also known as fluorescent lamp. The luminous efficiency of electricity is 3 times higher than that of ordinary incandescent lamps, and its service life is 4 times higher than that of ordinary incandescent lamps. Moreover, the temperature of the lamp wall is very low, and the light is relatively uniform and soft. The application field of fluorescent lamp is second only to incandescent lamp, and it has been widely used in houses, offices, shopping malls, hotels, workshops, hospitals, exhibition halls and many other places. It is also the main lamp to replace the inefficient incandescent lamp. There are two types of fluorescent lamps: straight tube type and compact type.
There are two kinds of straight fluorescent lamps: thick tube lamps and thin tube lamps. Generally, the inner wall of thick tube lamp is coated with halophosphate phosphor, while the inner wall of thin tube lamp is coated with tricolor phosphor, which can convert ultraviolet rays into more visible light, so the light-emitting efficiency of thin tube lamp is higher than that of thick tube lamp. A thin tube lamp with a nominal diameter of 26 mm can directly use the lamp holder of a thick tube lamp with a nominal diameter of 38 mm, and can also use an inductive rectifier or an electronic ballast. It is very convenient to replace the thick tube lamp with the thin tube lamp, which is a straight tube lamp to further improve the light efficiency.
Compact fluorescent lamp is a new type of electric light source which integrates rectifier and lamp tube, so it is named because of its compact shape and structure. Distributed inductance rectifier or electronic ballast is called electronic energy-saving lamp in China. This kind of lamp uses tricolor phosphor and has high luminous efficiency. Coupled with the low-power electronic ballast, the power-saving effect is very obvious. Its color rendering is good, the stroboscopic effect has been greatly improved, and the startup performance has also been improved. It has the advantages of incandescent lamp and fluorescent lamp. The compact fluorescent lamp can be directly installed on the incandescent lamp base, which can save electricity by 70% ~ 80% under the same luminous flux. It is ideal to replace incandescent lamps.
(2) High pressure mercury lamp. High-pressure mercury lamp is an electric light source that uses high voltage generated by mercury discharge to obtain visible light. The luminous tube is filled with mercury and argon, some inner shells are coated with fluorescent powder, and some are completely transparent. Its luminous efficiency is similar to that of ordinary lamps, but its service life is longer. Its disadvantages are poor color rendering, blue-green light and lack of red components. Except for green objects, most of them are gray and cannot be started instantly.
High-pressure mercury lamps are mostly used in public lighting places with high illumination, such as tall factories, gymnasiums and warehouses. Road streets, squares, stations, docks, parking lots, overpasses, trading markets, etc. , widely used in public places.
(3) Metal halide lamps. Metal halide lamp is an electric light source that emits a mixture of metal mercury vapor and decomposition products of metal halides such as sodium, thallium, indium, scandium, dysprosium, cesium and lithium after being electrified. It is a new type of lamp developed on the basis of high-pressure mercury lamp. The electrical structure of the high-pressure mercury lamp is very similar to that of the high-pressure mercury lamp except that metal halide is added.
Compared with high-pressure mercury lamp, metal halide lamp has higher luminous efficiency, better color rendering and longer service life, but it needs orientation in use.
Metal halide lamps can not only replace high-pressure mercury lamps, but also be used for outdoor lighting in places that require good color rendering, such as exhibition halls, art galleries, entertainment centers, large parks, hotels and restaurants. Low-power metal halide lamps can also be used for indoor lighting of houses and office buildings without starting performance requirements to replace inefficient incandescent lamps.
(4) high-pressure sodium lamp. High-pressure sodium lamp is an electric light source that uses high-pressure sodium vapor to discharge. In addition to the proper amount of mercury, argon or xenon, excessive sodium is added into the light-emitting tube. Because the excitation potential of sodium is lower than that of mercury, it mainly depends on sodium discharge to emit light, so it is also called sodium lamp.
High-pressure sodium lamp emits golden light, which has high luminous efficiency in electric light source. Its luminous efficiency and service life are better than those of high-pressure mercury lamps. Its main disadvantage is poor color rendering, but there have been improved high color rendering sodium lamps with better color rendering than ordinary high pressure mercury lamps. Ordinary high-pressure sodium lamps are mainly used in roads, tunnels, ports, docks, stations, squares, bridges and other places that do not require high light color. They are also widely used in some factories, sports and entertainment places, and their application scope is constantly expanding. In many occasions, high-pressure sodium lamp can replace high-pressure mercury lamp, saving lighting electricity.
(5) Low pressure sodium lamp. Low-pressure sodium lamp is an electric light source that uses low-pressure sodium vapor to discharge light. Its glass shell is coated with infrared reflection film, which has small light attenuation but high luminous efficiency. The light emitted by low-pressure sodium lamp is monochromatic yellow light with poor color rendering, so it is used in places where there is no requirement for light color. But objects with good fog permeability and small color difference can be seen clearly. In order to ensure the normal operation and avoid shortening the service life, the low-pressure sodium lamp should not be moved when in use, and the switching times should be reduced as much as possible. Low-pressure sodium lamp is also an efficient and energy-saving lamp to replace high-pressure mercury lamp, and its use places are also expanding.
Application of rare earth tricolor compact fluorescent lamp
Rare earth tricolor compact fluorescent lamp is an advanced compact fluorescent lamp product, which has high energy saving and shows the development trend of high and low power, plug-in and dimmable. Intelligent compact fluorescent lamps will be more and more widely used.
Among them, 2-volt, 2-watt and 2-volt, 3-watt compact fluorescent lamps have been lighting lamps in many families; With the development of high-power compact fluorescent lamp, its market will gradually expand and mercury lamp will be replaced by it. Plug-in compact fluorescent lamps will have 2 volts, 3 volts, spiral and other forms; Plug-in rectifier is already an electronic ballast plug-in rectifier and an energy-saving inductor plug-in rectifier, but the cost performance of the new product will be better. The technology of dimmable, intelligent and compact fluorescent lamp is becoming more and more mature.
The application scope of compact fluorescent lamps includes large public places, home lighting, apartments and so on.
Identification of rare earth tricolor compact fluorescent lamp
The quality appraisal method of rare earth tricolor compact fluorescent lamp is as follows:
(1) From the price point of view. For example, 2-volt energy-saving lamps, high-quality rare earth tricolor lamps are more than 20 yuan each, ordinary rare earth tricolor lamps are about 10 yuan each, and inferior halogen powder lamps can be as low as 3 ~ 5 yuan each.
(2) It is necessary to purchase compact fluorescent lamp products that have passed the two lamp standards (safety standards and performance standards) of the State Bureau of Quality and Technical Supervision 1998, 1999 and 2000.
(3) Buy lamps that have obtained the national energy-saving product certification.
(4) Check whether the product label is complete. Products that meet the sales requirements include registered trademarks, contact numbers, factory names, addresses, etc.
(5) Halogen powder lamps, which look like compact fluorescent lamps, are produced with calcium halophosphate phosphors, and the lighting effect is poor. When lit, you can see that the lamp tube is dark yellow. After a short period of use, the filament is obviously black, the brightness is reduced, and the service life is about 10 times shorter than that of high-quality rare earth energy-saving lamps. Experts have been calling for stopping the production of this kind of lamp. The production of this kind of lamp not only tarnishes the reputation of compact rare earth fluorescent lamp, but also wastes resources and causes serious mercury pollution.
Correct use of electronic ballast
In energy-saving lighting, besides selecting lamps with high efficiency and reasonable light distribution, there is also a problem that is often overlooked: the energy consumption of rectifiers using gas discharge light sources.
Rectifier is a control device used for starting and limiting current of gas discharge lamp. Because the gas discharge lamp has negative volt-ampere characteristics, it should be equipped with a rectifier to start the discharge of the lamp, limit the ionization and temperature rise of inert gas in the lamp, and make the mercury vapor pressure rise. When electrons bombard mercury vapor, ultraviolet rays generated after discharge excite fluorescence, thus emitting light. After starting, the rectifier acts as a current limiter to make the lamp start to work normally. The commonly used rectifier is inductance rectifier.
Inductive rectifier is a device with high inductance and high resistance, which is connected in series with the lamp. It consumes not only active power, but also reactive power, and the power factor is also very low, which leads to the decline of lighting efficiency.
Compared with ordinary inductance rectifier, electronic ballast has the advantages of low active power consumption, high power factor, fast ignition speed and no noise interference. The power saving rate is as high as about 75%, and the power factor can be increased from about 0.5 to above 0.9. At the same time, when the power frequency is increased from 50 Hz to 25 ~ 40 kHz, the stroboscopic effect is less, which is very beneficial to vision and production safety, and greatly reduces the chances of vision fatigue and personal injury. It is best not to use inductive rectifier in places with high requirements for vision and health or places where rotating machinery works.
It is worth noting that the products sold in the market have advantages and disadvantages. When using electronic ballasts, especially compact fluorescent lamps, we should not only pay attention to the validity period, but also prevent the pollution of higher harmonics, especially the third harmonic, to the power grid. Using too many inferior products is easy to burn out lamps, and it will also affect the safe operation of other electrical equipment.