Listed below are a few factors that we consider when designing outdoor LED lighting systems in outdoor lighting applications.
Working Environment of Outdoor LED Floodlights
Due to the complex working environment of LED outdoor lighting, it is affected by natural conditions such as temperature, ultraviolet rays, humidity, rain, sand, chemical gases. Over time, it will cause serious LED light degradation problems. Therefore, finally, outdoor lighting designers should consider the impact of these external environmental factors on LED outdoor lighting fixtures when designing.
Considerations in Selecting Heat Dissipation Materials for LED Lamps
The material and heat sink materials used are designed as a whole to solve the heating problem of the LED. Generally, aluminum or aluminum alloy, copper or copper alloy and other alloys with good heat conductivity are used. The heat dissipation includes air convection convection convection, strong wind chilled convection, and heat pipe convection. (Air jet cooling is also a type of heat dissipation similar to heat pipe heat dissipation, but the structure is more complex.)
The choice of heat dissipation method directly affects the cost of the lamp. It should be considered comprehensively and the best solution should be chosen together with the designed product.
The design and selection of the LED projector is also very important. At present, transparent plexiglass materials, etc. The conventional LED projector used is a clear glass product. Material selection for LED projector is all about product quality and positioning of design.Generally speaking, the exterior of outdoor LED floodlights is made of traditional glass products, which is the best choice for the production of long-lasting, high-quality lamps. LED floodlights made of clear plastic, plexiglass and other materials are better for indoor lighting, but they have a limited lifespan when used outdoors. Factors such as outdoor exposure to sunlight, ultraviolet rays, sand and dust, chemical gases and temperature changes between day and night shorten the aging life of the lampshade. Second, if the material used is dirty and difficult to clean, this reduces the transparency of the projector and affects the light output. Therefore, the material used for outdoor LED projectors should be selected and designed according to these considerations.
Storage of Outdoor LED Chips
Currently, most of the internationally produced LED lamps are produced by mounting multiple 1W LEDs in series and in parallel. 30W, 50W or larger modules must be used to obtain the required power. The inner materials of these LEDs are made with epoxy resin and cased with silicon. The difference between the two is that the projector combined with epoxy resin has low temperature resistance and is easy to age over time. Combining with silicone has better temperature resistance, so when using it, care should be taken with the selection.
It is better to use multi-chip and heat sink integrated case, or use aluminum substrate multi-chip system, and then connect to the heat sink with phase change material or heat dissipation silicon grease and thermal resistance. For lamps using LED modules, the module substrate is usually a copper substrate, and the connection between it and the external radiator should use a good phase change material or a good heat dissipating silicone grease to ensure that the heat on the copper substrate can be transferred. If the external radiator is not well taken care of in time, it is easy to accumulate heat and cause the temperature of the module chip to rise too high, which affects the normal operation of the LED chip. We believe that the multi-chip package is suitable for the production of general lighting lamps, and the module package is suitable for the production of compact LED lamps (such as headlights of the main lighting of cars) where space is limited.
On the Design of Airflow Radiators of Outdoor LED Projectors
The radiator is a very critical component of the LED lamp. Its shape, volume and heat dissipation surface area must be properly designed. If the radiator is too small and the operating temperature of the LED lamp is too high, this will affect the luminous efficiency and lifetime. If the radiator is larger than necessary, this will increase the material consumption, that is, the cost and weight of the product, and this will reduce the competitiveness of the product. It is essential to design an LED projector radiator that fits the design. The design of the radiator is shaped by the following steps:
- The power that the LED lamp must dissipate should be clarified
- Some parameters for the design of the heatsink: the specific heat of the metal, the thermal conductivity of the metal, the thermal resistance of the chip, the thermal resistance of the radiator, the thermal resistance of the surrounding air, etc. must be determined
- The type of heat dissipation should be determined (natural convection heat dissipation, strong wind cooling, heat pipe heat dissipation and other methods of heat dissipation) From the cost comparison: natural convection heat dissipation is the lowest cost, strong wind cooling is moderate. , heat pipe heat dissipation is relatively expensive, and air-jet cooling is the most expensive.
- Determine the maximum allowable operating temperature of the LED lamps (ambient temperature plus the maximum allowable temperature rise of the lamps)
- Calculate the volume and heat dissipation area of the radiator and determine the shape of the radiator
- After combining the radiator and LED lamps to create the projector, the lighting system must be activated for more than eight hours. To verify that the calculation is correct, the temperature of the lamp should be checked at 39℃-40℃ room temperature to see if it meets the heat dissipation requirements. If the conditions of use are not met, the parameters must be recalculated and adjusted.
- The gasket between the radiator and the LED projector must be waterproof and dustproof. Anti-aging rubber pad or silicone rubber pad should be placed between the LED projector and the radiator, and stainless steel bolts should be used to fix it, to ensure that the gasket is waterproof and dustproof.
Contact us for our exterior lighting designs and applications, which we carry out in accordance with the latest technical specifications for outdoor lighting LED projectors, as well as urban road lighting design standards.