Lighting Device Fan Placement for Thermal Management
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Solution Overview
Problem
Solid state lighting (SSL) devices, such as LED-based lighting, face challenges in thermal management, leading to variations in light color and reduced customer satisfaction due to insufficient heat dissipation, especially in high-power applications where scaling up heat sinks is impractical, and the integration of cooling fans can increase noise and reduce fan lifetime.
Innovation Solution
A lighting device design featuring a slanted support structure with a fan positioned closer to the air inlet than the outlet, maximizing fan diameter for improved airflow and reduced noise, while thermally decoupling the fan from SSL elements, and incorporating a conduit with fins and air guide members to enhance heat dissipation without overheating the fan.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If the capacity of the fan is increased to cool the SSL elements, then the cooling effectiveness is improved, but the noise levels of the fan increase
Solution Approach 1:
The fan is mounted slanted relative to the support structure section, changing the spatial orientation from a conventional axial position to an inclined position. This dimensional change allows the fan to draw cool air from the air inlet more effectively while directing it across the SSL elements, improving cooling performance without requiring increased fan capacity that would generate more noise
Solution Approach 2:
The conduit acts as an intermediary structure that guides and directs air flow from the air inlet to the air outlet, passing over the support structure. The conduit with its integrated fins creates a controlled air path that enhances heat dissipation efficiency, allowing the fan to operate at lower capacity while maintaining effective cooling
2Temperature
If the heat sink is scaled up to dissipate heat from high-power SSL elements, then the heat dissipation capability is improved, but the device volume increases making it impractical for standard light bulb sizes
Solution Approach 1:
The heat sink fins are merged with the conduit structure, creating an integrated assembly where the conduit serves both as an air guidance channel and as a heat dissipation structure. This combination eliminates the need for a separate large heat sink, achieving effective heat dissipation within a compact volume suitable for standard light bulb applications
Solution Approach 2:
The conduit structure performs multiple functions simultaneously: it guides air flow from the inlet to the outlet, provides a mounting structure for the fan, and incorporates fins for heat dissipation. This multi-functionality allows the same structural element to address cooling requirements without increasing overall device volume
3Temperature
If the fan is placed in the direct vicinity of the SSL elements, then the cooling efficiency is improved, but the heat generated by the SSL elements reduces the lifetime of the fan
Solution Approach 1:
The fan is extracted from direct contact with the hottest regions near the SSL elements and positioned within the conduit structure at an optimized location. This separation allows the fan to cool the SSL elements effectively through the guided air flow while being protected from the most extreme thermal conditions that would reduce its lifetime
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This design improves airflow and heat dissipation, reduces noise, and extends the lifetime of the lighting device by optimizing fan placement and heat sink configuration, ensuring effective cooling even in closed luminaires.
Implementation Method 1
a cooling fan is integrated in the design of the lighting device to force air over the SSL element, thereby reducing the heat dissipation requirement of heat sinks
Implementation Method 2
a conduit from said air inlet to said air outlet such that the conduit extends over the support structure
Data Source
AI summary
Disclosed is a lighting device (1) comprising a housing (80), an air inlet (22) and an air outlet (24); a support structure (30) in said housing extending in between said air inlet and said air outlet, said support structure including a section (32) carrying at least one solid state lighting element (10); a conduit (20) from said air inlet to said air outlet such that the conduit extends over the support structure; and a fan (40) mounted in said conduit, wherein the fan is located closer to the air inlet than to the air outlet. A luminaire including such a lighting device is also disclosed.