Roof Window Frame with Integral Insulation Reducing Thermal Bridging
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Solution Overview
Problem
The installation of roof windows often results in thermal bridging and significant heat loss due to high thermal transmittance U-values of the roof window frame materials, which act as a thermal bridge between the inside and outside of a building, and insufficient insulation around the frame components.
Innovation Solution
A roof window frame design featuring a reduced thickness base member with an integral insulation means, allowing the use of existing weatherproof flashings without modification, and incorporating a support member for enhanced structural strength and insulation, reducing the thermal transmittance U-value by up to 50%.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If additional insulation collars or bands are added around the roof window frame, then thermal insulation is improved, but the existing weatherproof flashings must be adapted or bent to accommodate the extra space
Solution Approach 1:
The insulation collar is merged with the window frame to form a single integrated component. The insulation material is positioned within a recess in the frame member, eliminating the need for separate insulation collars and allowing the flashings to remain unchanged. This integration resolves the contradiction by providing thermal insulation without requiring flashing adaptation.
Solution Approach 2:
The insulation is incorporated by creating a recess in the frame member, effectively using the depth dimension of the frame to accommodate insulation material. This allows the external dimensions and flashing interface to remain unchanged while adding thermal insulation within the frame's internal structure.
2Loss of energy
If wedge shaped insulation collars are used to enclose the roof window frame, then thermal insulation is improved, but the existing external weather proof flashings have to be adapted or bent
Solution Approach 1:
The insulation collar function is merged into the window frame structure itself. The frame member includes a recess that accommodates insulation material, eliminating the need for separate wedge-shaped insulation collars and the associated flashing adaptation work. This resolves the manufacturing complexity while maintaining thermal insulation performance.
3Strength
If the roof window frame material has high thermal transmittance U-value, then structural strength is maintained, but thermal bridging occurs between inside and outside of the building
Solution Approach 1:
The frame member has different properties at different locations: the outer portion maintains the original structural material for strength, while an inner recess portion accommodates insulation material with low thermal transmittance. This local differentiation allows the frame to simultaneously provide structural strength and reduce thermal bridging.
Solution Approach 2:
The window frame becomes a composite structure combining structural material (for strength) and insulation material (for thermal performance). The insulation material is positioned within a recess in the frame member, creating a composite construction that achieves both structural and thermal performance requirements.
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 solution provides improved thermal performance with the same external dimensions as an unaltered frame, reducing thermal bridging and heat loss, and maintaining the same external dimensions as the standard frame, thus addressing the aesthetic and thermal issues associated with existing insulation methods.
Implementation Method 1
the integral insulation means having a uniform thickness between these two main surfaces along the length and height of the integral insulation means
Data Source
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AI summary
A roof window frame (1) comprising at least four elongate frame members (2) joined about their ends (3) forming a quadrangular shaped frame defining a central aperture (4). Each frame member having a main aperture facing surface (5) and a main roof facing surface (6) the two main surfaces facing in opposite directions with the thickness of the frame member being defined between these main surfaces. The frame members comprising a reduced thickness base member (8) and an integral insulation means (9) carried on the main roof facing surface (6) of the reduced thickness base member (8) so that the overall size and shape of the reduced thickness base member (8) and the integral insulation means (9) is the same as an unaltered frame member for the same specification of roof window.