Sliding Window Sash Low Emissivity Cavity Surface
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Solution Overview
Problem
Existing sliding window and door sashes with composite profiles face challenges in reducing heat transfer through thermal radiation and convection, as the cavities within these profiles often promote heat transfer due to their design.
Innovation Solution
The implementation of a sash design featuring a low emissivity surface, either an untreated aluminum surface or a low emissivity foil, on one side of the cavity between metallic members, significantly reduces heat transfer by thermal radiation. This surface has an emissivity of less than or equal to 0.3, and is typically integrated with insulating strips and plastic profiles to maintain thermal insulation while allowing space for hardware.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If a cavity is provided in the composite profile to accommodate hardware, then hardware can be installed for locking the sliding window or door, but heat transfer caused by thermal radiation and convection is promoted
Solution Approach 1:
An insulating member is introduced as an intermediary substance within the cavity to block heat transfer pathways. This insulating member fills the space between the inner and outer metallic members, preventing direct thermal contact while still allowing the cavity to accommodate the necessary locking hardware.
Solution Approach 2:
The locking hardware is nested within the cavity structure, with the insulating member surrounding the hardware components. This nesting arrangement allows the hardware to be housed within the profile while the insulating material maintains thermal barriers around the hardware, minimizing its impact on thermal performance.
2Adaptability or versatility
If the cavity is made large enough to accommodate hardware, then locking mechanism can be installed, but thermal insulation performance deteriorates
Solution Approach 1:
The insulating member is applied locally within the cavity regions where heat transfer occurs, rather than requiring the entire cavity to be filled. This allows selective insulation of critical thermal pathways while maintaining adequate space for hardware installation in less critical areas.
Solution Approach 2:
The profile structure becomes a composite system combining metallic members for structural strength, insulating materials for thermal performance, and hardware components for functionality. This composite approach allows each material to perform its optimal function while working together as an integrated system.
3Reliability
If conventional surface treatments are applied to metallic members, then aesthetic appearance and corrosion resistance are improved, but emissivity increases and thermal insulation performance deteriorates
Solution Approach 1:
Different surface treatments are applied to different portions of the metallic members. The outer surfaces exposed to aesthetics and corrosion requirements receive conventional treatments, while the inner surfaces facing the cavity maintain untreated or low-emissivity surfaces to minimize thermal radiation.
Solution Approach 2:
The metallic members are segmented into different functional zones: outer surfaces for aesthetic and corrosion protection, and inner cavity-facing surfaces for thermal performance. This segmentation allows independent optimization of each surface for its specific function.
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 configuration effectively minimizes heat transfer caused by thermal radiation, maintaining good thermal properties while accommodating hardware within the cavity, thus enhancing the energy efficiency of sliding windows and doors.
Implementation Method 1
low heat transfer caused by thermal radiation can be achieved
Implementation Method 2
one or more insulating members connecting the metallic members
Implementation Method 3
heat transfer caused by thermal radiation and convection is promoted
Data Source
Figure 1
Figure 2A~2B
Figure 2C
AI summary
A sash (2) for a sliding window (1) or a sliding door includes at least two aluminium members (4, 5) connected by one or more insulating strips (7, 8). The two aluminium members (4, 5) and one of the insulating strips (7) at least partially confine a cavity (9) having a first side (10) in a direction (y) perpendicular to a plane (x-z) in which the sash (2) extends and a second side (11) opposite to the first side (10). A low emissivity surface (6a) is disposed along the first side (10) or the second side (11) and has an emissivity ε of less than or equal to 0.3.