Solar Receiver Tube Assembly With Vacuum Sealing and Bellows
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Solution Overview
Problem
Solar thermal power plants face challenges in achieving high concentration factors and reducing losses due to the low density of solar energy collection, particularly in linear concentrator systems, which limits the overall performance of the concentration plant.
Innovation Solution
An efficient assembly procedure for improved receiving tubes in linear solar concentrators, involving the integration of an expansion compensating system, evaporable and non-evaporable getters, and Kovar rings, along with detailed manufacturing steps for metal and glass tubes, bellows assemblies, and vacuum creation, to enhance the concentration factor and reduce losses.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If linear concentrators are used, then installation is easier with fewer degrees of freedom, but concentration factor is lower and temperatures reached are lower
Solution Approach 1:
The patent changes the geometric parameters of the receiving tube, specifically using a smaller inner diameter (15-25mm) to increase the concentration factor. This parameter modification allows linear concentrators to achieve higher temperatures while maintaining installation simplicity.
Solution Approach 2:
The patent employs composite construction with glass outer tube and metal inner tube, combining the optical transparency of glass with the thermal conductivity and structural strength of metal. This composite structure optimizes both the concentration capability and thermal performance of linear concentrators.
2Loss of energy
If vacuum is created between glass and metal tube, then heat losses are reduced, but assembly complexity increases with multiple components
Solution Approach 1:
The patent segments the receiving tube into distinct functional components: glass outer tube, metal inner tube, vacuum space, and various sealing elements. This segmentation allows each component to be optimized independently while maintaining the vacuum insulation benefit.
Solution Approach 2:
The patent implements a nested structure where the metal tube is placed inside the glass tube, creating a concentric arrangement. This nesting approach efficiently creates the vacuum space between layers while minimizing overall dimensions and reducing heat transfer pathways.
3Stability of the object's composition
If expansion compensating device is added, then thermal expansion is managed, but device complexity and assembly steps increase
Solution Approach 1:
The patent explicitly addresses thermal expansion by incorporating an expansion compensating device (bellows) that accommodates the differential thermal expansion between the glass and metal tubes. This device maintains the vacuum seal while allowing for dimensional changes during thermal cycling.
Solution Approach 2:
The expansion compensating device acts as an intermediary element between the glass outer tube and metal inner tube, mediating the thermal expansion differences. This mediator maintains the integrity of the vacuum space while accommodating dimensional changes without requiring complex assembly procedures.
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 described assembly procedure results in a receiving tube design that increases the concentration factor and reduces losses, thereby enhancing the performance of solar thermal power plants by optimizing the integration of components and vacuum creation within the tube.
Implementation Method 1
Creation of the vacuum in the intermediate zone, between the glass and the metal tube
Implementation Method 2
Evaporable getter with attachment clip
Implementation Method 3
Non-evaporable loop getter and closure system
Data Source
AI summary
The invention relates to a method for producing a solar power receiving tube and to the resulting tube, which is of the type that includes: an outer glass tube, an inner metal absorber through which a heat-transfer fluid flows, and an intermediate area in which the vacuum is produced. The method comprises the following steps:i. Production of the metal tubesii. Production of the glass tubes: namely a longer central glass tube and two shorter glass tubes for the ends.iii. Process for the production of the Kovar rings or glass-metal transition elementsiv. Process for the welding of the Kovar rings to the tubesv. Process for the production of the bellows or expansion compensating devices assembliesvi. Assembly of the products obtained in the preceding operationsvii. Creation of the vacuum and anodising of the welds.