Comparison-based optical study on a point-line-coupling-focus system with linear Fresnel heliostats

Area of Science:

• Solar Energy Engineering
• Optical Physics
• Renewable Energy Systems

Background:

• Concentrated solar power (CSP) systems require efficient light collection.
• Beam-down solar towers offer advantages in receiver placement and optical efficiency.
• Linear Fresnel heliostats provide a cost-effective alternative to parabolic dishes.

Purpose of the Study:

• To investigate the optical characteristics of a beam-down solar tower with a parabolic linear Fresnel heliostat (PLCF).
• To compare the optical performance of the PLCF system against conventional beam-down solar tower systems.
• To determine the optimal heliostat facet design for enhanced system efficiency.

Main Methods:

• Theoretical analysis of optical characteristics for a PLCF system with a hyperboloid reflector.
• Development of a Monte Carlo ray-tracing (MCRT) model accounting for solar position and optical surface errors.
• Comparative study of optical performance between PLCF and conventional systems (flat/spherical heliostats).

Main Results:

• The PLCF system demonstrates potential for reduced spot size and improved optical efficiency.
• The MCRT model provides a robust method for evaluating optical performance under realistic conditions.
• Optimal square facets for linear Fresnel heliostats were proposed for 3D-CPC receivers.

Conclusions:

• The PLCF beam-down solar tower is a promising CSP technology with enhanced optical performance.
• Accurate modeling, including solar position and surface errors, is crucial for system optimization.
• The proposed heliostat design and receiver matching can further boost solar energy concentration.