Issues in the thermal design of LED streetlights include: arbitrary determination of heat sink fin surface area; irrational fin layout that fails to account for the luminaire's operational orientation, thereby compromising fin performance; an overemphasis on heat conduction at the expense of convective heat dissipation; and a failure to recognize that heat must ultimately be dissipated through the luminaire's external surface area-despite the adoption of measures such as heat pipes, loop heat pipes, and thermal interface materials. Furthermore, the uniformity of heat transfer is often overlooked; significant temperature gradients across the fins can render some fins ineffective or limit their performance.
This utility model presents a high-power LED streetlight luminaire designed for convective heat dissipation. It comprises a lamp head assembly, a heat sink assembly, and a tail assembly. The heat sink assembly features an arc-chord cylindrical shell open at both ends, with vertical side faces on either side of the curved surface; these vertical faces contain arrays of through-holes. Inside the shell, 4 to 10 axially arranged vertical heat-conducting ribs are fixed to both the curved and chordal surfaces of the shell. These ribs and the vertical side faces of the shell also feature arrays of through-holes, creating 5 to 11 heat dissipation channels for hot airflow within the assembly. The advantages of this design include multiple internal airflow channels and the use of vertical ribs as additional heat dissipation surfaces, resulting in increased heat exchange area and high heat dissipation efficiency.
Heat dissipation is a critical challenge for LED streetlights. It directly impacts the actual luminous efficacy of the LEDs. Moreover, given the high brightness requirements, significant heat generation, and harsh outdoor operating environments associated with these lights, poor heat dissipation leads to rapid LED degradation and reduced stability. While outdoor streetlights require specific Ingress Protection (IP) ratings against dust and water, robust IP protection often impedes effective heat dissipation. Resolving these two contradictory yet equally pressing issues is a key aspect that should be addressed in the design of road lighting fixtures.
