Abstract:
Direct absorption solar thermal collectors have recently been
shown to be a promising technology for photothermal energy conversion but many parameters affecting the overall performance of
such systems have not been studied in depth, yet alone optimized.
Earlier work has shown that the overall magnitude of the extinction coefficient can play a drastic role, with too high of an extinction coefficient actually reducing the efficiency. This study investigates how the extinction coefficient impacts the collector
efficiency and how it can be tuned spatially to optimize the efficiency, and why this presents a unique design over conventional
solar thermal collection systems. Three specific extinction profiles
are investigated: uniform, linearly increasing, and exponentially
increasing with the exponentially increasing profile demonstrating
the largest efficiency improvement
