What kind of heat dissipation structure does LED Bulkhead use

In the professional lighting sector, LED bulkheads (bulkheads/porthole lights) are widely used outdoors, in corridors, underground parking lots, and in industrial environments due to their ruggedness and high IP65 or higher ratings. However, their high IP65 housing design presents unique heat dissipation challenges.

The lifespan and lumen maintenance (e.g., L70 standard) of LEDs are closely related to the chip's junction temperature (Tj). Temperature is the primary factor affecting LED lifespan. Therefore, a professional LED bulkhead must have an efficient and reliable heat dissipation structure to quickly dissipate heat away from the LED chip to ensure long-term operation, especially in high ambient temperatures, while maintaining its expected lifespan of 50,000 hours or more.

Three Core Components of a Bulkhead's Heat Dissipation Structure

The LED bulkhead's heat dissipation system is a complex, multi-layered structure comprised of three key components working in tandem: heat source management, heat conduction paths, and heat convection/radiation.

1. Heat Management: LED Module Substrate Selection

The first step in heat dissipation is to transfer heat away from the bottom of the LED chip.

Metal Core Printed Circuit Board (MCPCB): High-quality LED bulkheads almost exclusively utilize MCPCB instead of traditional FR4 fiberglass boards. MCPCBs, with an aluminum substrate as their core, possess extremely high thermal conductivity. This ensures that heat generated by the LED chip during operation is transferred to the aluminum substrate surface as quickly as possible.

Highly Thermally Conductive Adhesive and Solder: Specialized highly thermally conductive solder or adhesive must be used between the LED chip and the MCPCB to minimize thermal contact resistance. The precision and material purity of this process in a professional bulkhead are key differentiators of product quality.

2. Heat Transfer Path: Integration of Housing Material and Structure

After heat is transferred from the MCPCB, it needs a reliable path to the exterior surface of the luminaire.

Die-cast Aluminum Alloy Housing: While many bulkhead housings utilize polycarbonate (PC) to meet IK impact resistance requirements, the critical heat dissipation components within are typically still die-cast aluminum alloy. Professional structural design secures the MCPCB to the aluminum alloy heat sink.

Structurally Integrated Heat Sink: In some high-performance LED bulkheads, the main housing (particularly the back) is designed as a structural heat sink with heat sink functionality. Precise fin spacing and thickness are designed to maximize the surface area in contact with ambient air.

3. Heat Convection and Radiation: Challenges in Sealed Environments

Because bulkheads are typically highly sealed (e.g., IP66), internal heat dissipation relies primarily on conduction to the housing, where it is then dissipated through convection and radiation.

Maximized Surface Area: The effective heat dissipation surface area of ​​the luminaire housing is crucial to heat dissipation efficiency. Even if the housing is made of PC, the metal heat sink within ensures even heat distribution through multiple thermal vias.

Color and Coating Effects: The color and surface coating of the housing also affect heat radiation efficiency. Dark coatings (such as black or dark gray) have higher emissivity, which facilitates heat dissipation via infrared radiation in airtight environments.

Heat Dissipation Considerations for Drivers and Power Supplies

As another major heat source in luminaires, the driver's heat dissipation design is equally crucial. Driver failure is one of the main causes of LED luminaire failure.

Physical Isolation: Professional LED bulkhead structural design ensures a certain physical distance or isolation cavity between the driver and LED module. This prevents heat generated by the LED module from being transferred back to sensitive electronic components within the driver, such as electrolytic capacitors.

Driver Potting: Bulkhead drivers with high IP ratings are typically potted with thermally conductive epoxy or silicone. This not only provides additional IP protection against moisture but also evenly distributes heat generated by the driver's internal chips to the housing, further improving reliability in humid and vibrating environments.