Ceiling Luminaire Free Convection Cooling Design
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Solution Overview
Problem
Ceiling-mounted lamps in suspended ceilings experience inefficient cooling due to the accumulation of heated air, leading to reduced lifespan and impaired air circulation.
Innovation Solution
The lamp employs a housing design with inlet and exhaust channels that utilize free convection and the chimney effect to circulate air, creating a pressure difference that removes heated air without the need for fans, ensuring efficient cooling by directing cold air into the inlet channel and heated air out through offset outlet openings.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If air cooling is used for the luminaire, then cooling effect is achieved, but heated air accumulates in the suspended ceiling area reducing cooling efficiency
Solution Approach 1:
The air outlet is divided into two separate outlets positioned at different heights: a first air outlet opening at a lower level and a second air outlet opening at a higher level. This segmentation allows differentiated air discharge functions - the lower outlet handles initial cooling air flow while the higher outlet expels accumulated heated air, preventing heat buildup in the suspended ceiling area and maintaining sustained cooling efficiency
Solution Approach 2:
The solution transitions from a single-plane air outlet to a vertical dimension with multiple outlets at different heights. By arranging outlets at different vertical positions, the system creates a three-dimensional air discharge pattern that effectively removes heated air from the suspended ceiling space, resolving the contradiction between cooling efficiency and service life
2Temperature
If forced convection with fans is used, then cooling performance is improved, but device complexity and cost increase
Solution Approach 1:
The luminaire utilizes natural free convection currents and the chimney effect to achieve cooling without requiring external power sources or mechanical components. The dual air outlet configuration leverages buoyancy-driven air flow, where heated air naturally rises and exits through the upper outlet while cooler air is drawn in through the lower outlet, creating a self-sustaining cooling cycle that improves performance without adding complexity
Solution Approach 2:
The invention replaces the mechanical forced convection system (fans, motors, and control circuits) with a passive thermal convection system. By strategically positioning air inlet and outlet openings, the design harnesses natural air buoyancy and temperature-driven pressure differences to achieve effective cooling, thereby eliminating mechanical components and reducing device complexity
3Device complexity
If single air outlet is used, then device simplicity is maintained, but heated air accumulates reducing cooling effectiveness
Solution Approach 1:
The air outlet function is segmented into two distinct openings at different vertical levels. The first air outlet opening serves as the primary cooling air discharge, while the second air outlet opening specifically targets the removal of heated air that accumulates in the suspended ceiling area. This segmentation maintains relative structural simplicity while dramatically improving cooling effectiveness by addressing the root cause of heat accumulation
Solution Approach 2:
Different regions of the air outlet structure are assigned different functions based on their vertical positions. The lower first outlet is optimized for general cooling air discharge, while the elevated second outlet is specifically positioned to capture and expel heated air in the suspended ceiling space. This local differentiation of outlet functions enhances cooling effectiveness without requiring complex overall restructuring
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 enhances cooling efficiency by preventing heated air buildup, improving the lamp's performance and extending its lifespan by effectively removing heat without forced convection.
Implementation Method 1
a housing (5) with at least one inlet duct (7) for cooling a light source (6) accommodated in the housing (5) by means of air flowing in the inlet duct (7) due to free convection
Implementation Method 2
The second air outlet opening (12) is offset (arranged) relative to the first air inlet opening (7) in the direction of the main flow direction... a pressure difference is created between the second air outlet opening (12) and the first air inlet opening (7)
Implementation Method 3
cooling occurs by means of free convection, or more precisely, by means of the so-called chimney effect: heating the air within the inlet channel creates density differences, causing air to flow or be drawn into the inlet channel vertically
Data Source
Figure 1a
Figure 1b
Figure 2~3
AI summary
The invention relates to a luminaire (1) for installation in a ceiling (2), in particular for installation in a suspended ceiling, comprising a housing (5) having an inlet channel for cooling a lighting means (6) accommodated in the housing by means of air flowing in the direction of a main flow direction as a result of free convection in the inlet channel, wherein the inlet channel has a first air inlet opening (7) for admitting the flowing air into the inlet channel, and a first air outlet opening (8, 81) for discharging the air flowing in the inlet channel from the inlet channel; at least one exhaust air duct (9) having a second air inlet opening (11) for admitting the air flowing out of the first air outlet opening (8, 81) into the exhaust air duct (9), and a second air outlet opening (12) for discharging the air flowing in the exhaust air duct (9) out of the exhaust air duct (9), wherein the second air outlet opening (12) is offset in the direction of the main flow direction relative to the first air inlet opening (7).