Roofing Flashings With Return Hems For PV Integration
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing photovoltaic roofing systems face challenges in integrating specialized roof-mounted structures like photovoltaic devices with conventional roofing materials, particularly in ensuring weather-resistant performance and aesthetic appeal, especially on steep surfaces and in transition zones.
Innovation Solution
The development of flashing elements with specific cross-sectional shapes featuring laterally-extending flanges, return hems, and edgewalls that nest together when overlapping, eliminating potential leak points and providing continuous water protection by ensuring proper alignment and interlocking of photovoltaic and conventional roofing elements.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If photovoltaic roofing elements are integrated with conventional roofing products, then aesthetic effect and weather-resistant performance are improved, but installation difficulty increases particularly on steep surfaces
Solution Approach 1:
The roofing system is divided into separate photovoltaic roofing elements and conventional roofing products that can be installed independently. The photovoltaic elements are installed first as a base layer, followed by conventional roofing products overlaid on top, allowing each component to be installed using its own optimal methods without requiring complex integrated installation procedures.
Solution Approach 2:
The conventional roofing products are nested over the photovoltaic roofing elements, with the photovoltaic elements serving as an underlying layer. This nesting arrangement allows the conventional roofing to provide weather protection while the photovoltaic elements remain functional underneath, eliminating the need for specialized integrated flashing components.
2Productivity
If photovoltaic roofing elements are installed to cover a portion of the roof surface, then photovoltaic power generation is achieved, but aesthetic effect in the transition zone deteriorates
Solution Approach 1:
Different roofing products are used in different zones of the roof: photovoltaic roofing elements are installed in areas where power generation is desired, while conventional roofing products are used in transition zones and areas where aesthetic continuity is prioritized. This local differentiation allows the system to simultaneously achieve photovoltaic functionality and aesthetic appeal in different locations.
3Shape
If conventional roofing products are used alongside photovoltaic roofing elements, then aesthetic effect is maintained, but weather-resistant performance at transition zones deteriorates
Solution Approach 1:
The conventional roofing products themselves provide the weather-resistant function at transition zones by being overlaid over the photovoltaic elements. The overlapping installation configuration allows the conventional roofing to self-seal and protect the transition areas without requiring additional specialized flashing components, as the conventional roofing material's own properties provide the necessary weather protection.
Data Source
AI summary
The present invention relates more particularly to improved flashings for use in integrating specialized roof-mounted structures, such as photovoltaic devices for the generation of electrical energy, with conventional roofing materials on a roof. In one aspect, the invention provides a flashing element having a cross-sectional shape comprising a laterally-extending flange, the flange having an edge, a first end and a second end, the side flashing element comprising a return hem disposed at the edge and comprising a folded-over strip of material disposed over the top surface of the flange at the edge, the return hem having a first end disposed toward the first end of the edge, and a second end disposed toward the second end of the edge, wherein the total thickness of the return hem at its second end is no greater than the interior thickness of the return hem at its first end.