Thermal radiation is a fundamental heat transfer process, with certain basic
aspects still not fully understood. Furthermore, tailoring its properties has potential to
affect a wide range of applications, particularly thermophotovoltaics (TPV) and radiative
cooling.
TPV converts heat into electricity using thermal radiation to illuminate a photovoltaic
diode, with no moving parts. With its realistic efficiency limit up to 50% (heat source at
1200 <sup>o</sup>C), TPV has garnered substantial interest. However, state-of-the-art TPV
demonstrations are still well below theoretical limits, because of losses from generating
and efficiently converting or recycling thermal radiation. In this thesis, tailored integrated
photonic crystal structures are numerically simulated to enhance the efficiency of solar
TPV. Next, a high-temperature thin-film Si-based selective absorber and emitter is
designed, fabricated and experimentally characterized. It exhibits great potential to open
up new applications, as it lends itself to large-scale production with substantial
mechanical flexibility and excellent spectral selectivity for extended time periods, even
when operating under high operating temperatures (600 <sup>o</sup>C) for up to 6 hours, with
partial degradation after 24 hours. To perform this high-temperature characterization, an
emittance measurement setup has been built; its performance agrees well with
numerical simulations.
Second, a unique passive cooling mechanism known as radiative cooling is developed
to reduce the operating temperature of the photovoltaic diode. The significant effect of
radiative cooling as a complement for an all-passive-cooling TPV system is proposed
and numerically analyzed under a range of conditions. Furthermore, an outdoor
experiment has been performed to demonstrate the effect of radiative cooling on a
concentrating photovoltaic system, which can potentially be applied to the thermal
management of a TPV system. In summary, this work paves the way towards the
development of reliable, quiet, lightweight, and sustainable TPV and radiatively cooled
power sources for outdoor applications.
| Identifer | oai:union.ndltd.org:purdue.edu/oai:figshare.com:article/10700309 |
| Date | 25 November 2019 |
| Creators | Zhiguang Zhou (7908800) |
| Source Sets | Purdue University |
| Detected Language | English |
| Type | Text, Thesis |
| Rights | CC BY 4.0 |
| Relation | https://figshare.com/articles/Enhancing_Thermophotovoltaics_via_Selective_Thermal_Emitters_and_Radiative_Thermal_Management/10700309 |
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