Comparison Research On The Performance Of LED And High Pressure Sodium Lamp In Road Lighting

At present,common light sources for road lighting are high-pressure sodium lamp and LED light source.Under the premise of meeting the design standards of road lighting,there are still disputes over their energy saving and transmissivity in fog.Therefore,the energy efficiency and transmissivity in fog of high-pressure sodium lamp and LED light source are studied and it is significant for choosing the suitable lamps and designing the road lighting.In this paper,DIAlux evo lighting simulation software is used.The road lightings of high-pressure sodium lamp and LED light source are simulated on the fast road,trunk road,secondary roads,tributaries and other different road types with different lighting layout.Under the condition of satisfying the design standard of road lighting,power density,luminous flux and other lighting evaluation indexes of high-pressure sodium lamp and LED light source are analyzed and compared.In addition,based on MODTRAN atmospheric transmission model,the influence of visible wavelength on the light transmittance of street lamps under different typical atmospheric conditions is studied.The influence of different atmospheric particle components on the transmittance is discussed and analyzed.Meanwhile,taking full consideration of the emission spectrum of street lamps with different color temperature,their transmissivity in fog is compared and the difference of the transmissivity in fog between the high-pressure sodium lamp and the LED street lamp is discussed.The results show that,in terms of energy-saving efficiency:1)as for the lighting power density,the average theoretical power density of the 4-lane expressway is more than that of the high-pressure sodium lamp.For the 6-lane and 8-lane expressway,trunk road,secondary roads and tributaries,their average theoretical power value of the LED lamps is less than that of the high-pressure sodium lamp.2)As for the light flux,for the 4-lane expressway,4-lane trunk road,4-lane main road,2-lane and 3-lane branch,the light flux of LED light source is greater than that of the high-pressure sodium lamp.For other road type,the light flux of LED light source is less than that of the high-pressure sodium lamp.In terms of transmissivity in fog:1)the wavelength of visible light has a certain influence on its transmittance.When there is no fog in the atmosphere,the visible light transmittance increases with the increase of the wavelength;when the atmosphere is fog,the visible light transmissivity in fog decreases with the increase of the wavelength.2)The CO2 and H2O in the atmosphere have a strong absorption effect on the long-band part of the visible light.3)The type of light source and the change of color temperature have certain influence on transmittance,but this effect is very small in engineering.