Ribbed Roof Panel Shading Reduction for Photovoltaic Integration

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Solution Overview

Problem

Existing ribbed panels for building roofs with photovoltaic cells often result in some cells being shaded by the panel's ribs, reducing the performance of the photovoltaic device due to inadequate sunlight exposure.

Innovation Solution

A ribbed panel design with specific geometric configurations, including angled and proportioned ribs and protruding parts, ensures that photovoltaic cells are not shaded by the ribs under various lighting conditions, allowing for maximum sunlight exposure and efficient energy production.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Use of energy by moving object

If photovoltaic modules are added to the roofing surface, then energy production is improved, but shading by ribs reduces the performance

Engineering Contradiction:
Improveenergy productionVSAvoidenergy loss due to shading
Core Design Contradiction:
Use of energy by moving objectVSLoss of energy

Solution Approach 1:

The patent applies local quality by creating protruding parts with specific geometric characteristics (width L7, height H7, angles β) at specific locations on the panel. These protruding parts have different dimensions than the standard ribs, specifically designed to minimize shading while supporting photovoltaic cells. The ratio L7/L4≥5 and L7/L11≥5 ensures that the protruding parts are significantly wider than the rib widths, creating adequate spacing to prevent shading of photovoltaic cells while maintaining structural integrity.

Inventive Principle:
Principle #3Local quality

2Reliability

If the panel profile is modified to reduce shading, then photovoltaic performance is improved, but structural integrity may be compromised

Engineering Contradiction:
Improvephotovoltaic performanceVSAvoidstructural integrity
Core Design Contradiction:
ReliabilityVSStrength

Solution Approach 1:

The patent applies parameter changes by carefully controlling the geometric parameters of the protruding parts and ribs. The height H7 is constrained by the relationships H7/H4≥0.4 and H7/H4≤0.6, ensuring the protruding parts are neither too tall (which would cause shading) nor too short (which would compromise structural support). Similarly, H7/H11≥0.4 and H7/H11≤0.6 maintain appropriate proportions. The angles α, β, and γ are all defined as acute angles, optimizing both structural strength and shading reduction.

Inventive Principle:
Principle #35Parameter changes

3Productivity

If the panel design is optimized for photovoltaic cell placement, then energy efficiency is improved, but manufacturing complexity increases

Engineering Contradiction:
Improveenergy efficiencyVSAvoidpanel profile complexity
Core Design Contradiction:
ProductivityVSDevice complexity

Solution Approach 1:

The patent applies segmentation by dividing the panel profile into distinct functional elements: standard ribs (with width L4 or L11 and height H4 or H11) and protruding parts (with width L7 and height H7). This segmentation allows each element to be optimized independently - the standard ribs provide structural support while the protruding parts provide optimized support for photovoltaic cells with minimal shading. The clear geometric definitions and ratio relationships (L7/L4≥5, L7/L11≥5) simplify manufacturing by providing explicit dimensional guidelines.

Inventive Principle:
Principle #1Segmentation

Data Source

PatentEP3074578B1Panel, panel assembly, and related roofing
Publication Date: 2018.11.14 ARCELORMITTAL SA
  • EP3074578B1 patent drawingFigure 1~2
  • EP3074578B1 patent drawingFigure 3~4
  • EP3074578B1 patent drawingFigure 5

AI summary

The invention relates to a panel having a profile which has a width L1, and which includes: a first longitudinal edge that consecutively includes a first longitudinal rib including a top central portion having a height H4 and a width L4, two side flanges extending the top central portion on either sides thereof and toward the bottom, and a first sole plate having a width L3 and located within a plane P, the two side flanges forming an angle α with the plane P; at least one projecting portion extending away from the first sole plate and including a top plate, having a height H7 and a width L7, and two side web plates extending the top plate on either sides thereof and toward the bottom, thereby forming an angle β with the plan P; and a second longitudinal edge aligned with one of the projecting portions and consecutively including a second sole plate having width L9 and located within the plan P, a second longitudinal rib including a top central portion having H11 and width L11, and two side flanges extending the top central portion on either side thereof and toward the bottom, thus forming an angle γ with the plan P. The first longitudinal rib and the second longitudinal rib have shapes which enable each respective rib to be covered. The widths L1, L3, L4, L7, L9, and L11, the heights H4, H7, and H11, and the angles α, β, and γ observe the following relations: L7/L4 > 5, L7/L11 > 5, H7/H4 > 0.4, H7 ≥ ((H4 x (ab-be) - L3 x abe)/(ae + ab)), and H7 ≥ ((H11 x (cb-be) - L9 x cbe)/(ce + cb)), with a = tan α, b = tan β, c = tan γ, and e = tan 20°.