Cross-Flow Heat Sink Structure for Passive LED Fixture Cooling

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Solution Overview

Problem

Conventional LED fixtures in greenhouses face inefficiencies due to large heat sink fixtures that block sunlight, leading to reduced productivity and higher operational costs, as traditional linear heat sinks limit heat dissipation via convection and are prone to clogging with active cooling fans.

Innovation Solution

A cross flow heat sink with exposed fins on both sides and an upper surface is manufactured using extruded metal, allowing for increased air flow and efficient heat dissipation by drawing cooler air internally and expelling hot air, thereby enhancing heat dissipation without the need for active cooling.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of manufacture

If traditional linear heat sinks with wings parallel to the central axis are used, then heat dissipation structure is simple, but heat dissipation efficiency is limited due to minimal air movement in the middle of the fixtures

Engineering Contradiction:
Improveheat sink structure simplicityVSAvoidheat dissipation efficiency
Core Design Contradiction:
Ease of manufactureVSLoss of energy

Solution Approach 1:

The patent transitions from a traditional linear heat sink design with wings parallel to the central axis to a cross-flow heat sink design where fins extend perpendicular to the central axis. This dimensional change creates channels that facilitate air movement across the entire heat sink surface, including the middle section, thereby significantly improving heat dissipation efficiency while maintaining manufacturing simplicity through extrusion processes

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

2Loss of energy

If larger LED fixtures are used to dissipate heat, then heat dissipation capacity increases, but sunlight blocking increases causing shading on plants

Engineering Contradiction:
Improveheat dissipation capacityVSAvoidsunlight blocking
Core Design Contradiction:
Loss of energyVSObject-affected harmful factors

Solution Approach 1:

The patent changes the geometric parameters of the heat sink by extending fins perpendicular to the central axis and exposing them on both sides and the upper surface. This parameter change increases the effective heat dissipation surface area and improves air flow channels, allowing for more efficient heat removal from LED fixtures without increasing the overall fixture footprint, thereby reducing sunlight blocking while maintaining heat dissipation capacity

Inventive Principle:
Principle #35Parameter changes

3Loss of energy

If active cooling fans are used in smaller LED fixtures, then heat dissipation efficiency improves, but the fixtures quickly become inoperable due to clogging with dirt and bugs

Engineering Contradiction:
Improveheat dissipation efficiencyVSAvoidfixture operability
Core Design Contradiction:
Loss of energyVSReliability

Solution Approach 1:

The patent designs a passive cooling system where the cross-flow heat sink structure itself facilitates air movement through its geometry. The fins extending perpendicular to the central axis create natural convection channels that draw air through the heat sink without requiring active fans. This self-service approach eliminates the reliability issues associated with fan clogging while maintaining effective heat dissipation through the exposed fin surfaces

Inventive Principle:
Principle #25Self-service

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

The cross flow heat sink design significantly improves heat dissipation efficiency, allowing for higher power consumption in LED fixtures while minimizing shading and operational costs by leveraging increased surface area and air flow, thus optimizing greenhouse lighting conditions.

Implementation Method 1

Heat generated through conventional LED fixtures may dissipate based on convection, conduction or radiation. However, due to LED fixtures being suspended, there is minimal heat dissipation via conduction. Radiation is a function of the fixture temperature and may be significant, and convection is the primary method to dissipate heat.

Methodology Applied
Scientific EffectConvection: Convection

Implementation Method 2

Heat generated through conventional LED fixtures may dissipate based on convection, conduction or radiation. However, due to LED fixtures being suspended, there is minimal heat dissipation via conduction. Radiation is a function of the fixture temperature and may be significant

Methodology Applied
Scientific EffectThermal radiation: Thermal Radiation

Data Source

PatentEP3619468B1Systems and methods for a heat sink
Publication Date: 2024.09.18 FLUENCE BIOENG
  • EP3619468B1 patent drawingFigure 1
  • EP3619468B1 patent drawingFigure 2
  • EP3619468B1 patent drawingFigure 3

AI summary

Embodiments may utilize a series of exposed fins, which increase the surface area of the heat sink creating additional air flow. As hotter air rises within the system, cooler is drawn into the heatsink. The fins may be exposed on both sides of the longitudinal axis, allowing cooler air to be drawn towards the longitudinal axis above the heatsink and flow upward. This process may cool the fins. Additionally, the spacing between the fins may have to be wide enough to allow for air to freely enter the heatsink.