Contactless efficient two-stage solar concentrator for tubular absorber

Area of Science:

• Solar energy engineering
• Optical engineering
• Thermal sciences

Background:

• Two-stage solar concentrators are crucial for efficient solar thermal energy conversion.
• Existing designs often face limitations in achieving high concentration ratios and collection efficiencies simultaneously.
• The placement of secondary mirrors within evacuated tubes can complicate maintenance and design.

Purpose of the Study:

• To introduce a novel two-mirror solar concentrator design, termed the XX concentrator.
• To demonstrate the XX concentrator's ability to achieve high solar flux concentration and collection efficiency.
• To highlight the unique design feature of a sizable gap between the secondary mirror and the absorber.

Main Methods:

• The study presents the design and performance analysis of the XX concentrator.
• Concentration ratios and collection efficiencies were evaluated based on optical simulations and potentially experimental validation (details not fully specified in abstract).
• Key design parameters, including mirror geometry and gap size, were optimized.

Main Results:

• The XX concentrator achieves concentration ratios close to the thermodynamic limit with high collection efficiencies.
• One design variant reached 91.1% of the thermodynamic limit with 96.8% collection efficiency.
• Another variant achieved 92.5% efficiency and captured 95.1% of maximum concentration, with significant gaps between mirrors.

Conclusions:

• The XX concentrator represents a significant advancement in solar thermal energy collection technology.
• Its unique design, allowing the secondary mirror to be placed outside the evacuated tube, offers practical advantages.
• The achieved performance metrics are among the highest reported for practical solar concentrators, indicating strong potential for solar energy applications.