Reduction of radiative heat losses for solar thermal receivers

Clifford K. Ho; Joshua M. Christian; Jesus D. Ortega; Julius Yellowhair; Matthew J. Mosquera; Charles E. Andraka

doi:10.1117/12.2063152

7 October 2014 Reduction of radiative heat losses for solar thermal receivers

Clifford K. Ho, Joshua M. Christian, Jesus D. Ortega, Julius Yellowhair, Matthew J. Mosquera, Charles E. Andraka

Proceedings Volume 9175, High and Low Concentrator Systems for Solar Energy Applications IX; 917506 (2014) https://doi.org/10.1117/12.2063152
Event: SPIE Solar Energy + Technology, 2014, San Diego, California, United States

Abstract

Solar thermal receivers absorb concentrated sunlight and can operate at high temperatures exceeding 600°C for production of heat and electricity. New fractal-like designs employing light-trapping structures and geometries at multiple length scales are proposed to increase the effective solar absorptance and efficiency of these receivers. Radial and linear structures at the micro (surface coatings and depositions), meso (tube shape and geometry), and macro (total receiver geometry and configuration) scales redirect reflected solar radiation toward the interior of the receiver for increased absorptance. Hotter regions within the interior of the receiver also reduce thermal emittance due to reduced local view factors in the interior regions, and higher concentration ratios can be employed with similar surface irradiances to reduce the effective optical aperture and thermal losses. Coupled optical/fluid/thermal models have been developed to evaluate the performance of these designs relative to conventional designs. Results show that fractal-like structures and geometries can reduce total radiative losses by up to 50% and increase the thermal efficiency by up to 10%. The impact was more pronounced for materials with lower inherent solar absorptances (< 0.9). Meso-scale tests were conducted and confirmed model results that showed increased light-trapping from corrugated surfaces relative to flat surfaces.

Citation Download Citation

Clifford K. Ho, Joshua M. Christian, Jesus D. Ortega, Julius Yellowhair, Matthew J. Mosquera, and Charles E. Andraka "Reduction of radiative heat losses for solar thermal receivers", Proc. SPIE 9175, High and Low Concentrator Systems for Solar Energy Applications IX, 917506 (7 October 2014); https://doi.org/10.1117/12.2063152

ACCESS THE FULL ARTICLE

INSTITUTIONAL
Select your institution to access the SPIE Digital Library.

SELECT YOUR INSTITUTION

PERSONAL
Sign in with your SPIE account to access your personal subscriptions or to use specific features such as save to my library, sign up for alerts, save searches, etc.

PERSONAL SIGN IN

No SPIE Account? Create one

PURCHASE THIS CONTENT

SUBSCRIBE TO DIGITAL LIBRARY

50 downloads per 1-year subscription

Members: $195

Non-members: $335 ADD TO CART

25 downloads per 1 - year subscription

Members: $145

Non-members: $250 ADD TO CART

PURCHASE SINGLE ARTICLE

Includes PDF, HTML & Video, when available