Near-field thermophotonic system for power generation and electroluminescent refrigeration

Abstract

Near-field thermophotonic (TPX) systems that replace the high-temperature emitter in the thermophotovoltaic systems with a light-emitting diode (LED) have been reported to achieve low-grade heat harvesting and electroluminescent cooling, respectively. Nevertheless, the requirements for the two functionalities are different, leading to challenges to coordinate them. In our work, we propose a near-field TPX system composed of the CdTe LED and InP photovoltaic (PV) cell to realize two such functionalities with high performance. With wide-bandgap and high-quality semiconductors, the proposed system achieves a bandgap alignment at various temperatures and has low nonradiative recombination rates, thus enabling the functionality integration. Without changing the structures and materials, the system can switch functionality from power generation to electroluminescent refrigeration by tuning the LED temperature from 800 to 260 K while the PV temperature is maintained at 300 K. In addition, we suggest an additional layer of a thin Pt film on the PV cell to suppress phonon-polaritons parasitic heat transfer and further improve the system efficiency of both functionalities. This work theoretically demonstrates the possible integration of multiple functionalities and triggers further explorations of practical TPX systems.

Overcoming non-radiative losses with AlGaAs PIN junctions for near-field thermophotonic energy harvesting

“…Then, the device cannot produce power anymore: this is what happens between 0.1 and 0.4 V. Such feature was not observed in previous papers. For the ones using 0D models 18,20 , SRH recombination lifetimes considered were high, Yang et al even stating that SRH recombinations were negligible in their case. In our previous paper 19 , the high doping levels limited the SRH recombination rate.…”

“…S3). While these values are low, it should be possible to partially suppress the below-bandgap resonances, for instance with the use of Pt thin films 20 . This would help to come closer to the above-bandgap efficiency, and limit the heat extraction issue.…”

“…It can be used both as a heat engine and a heat pump/refrigerator. NF effects allowing to reach ELC more easily, it has been combined with the EL enhancement into a NF-TPX device [18][19][20] . Compared to TPV and NF-TPV, it can be competitive at much lower hot source temperature, down to 450-500 K, and could therefore have applications for low-grade waste heat recovery, as shown in Sec.…”

Machine learning enabled rational design for dynamic thermal emitters with phase change materials

“…Dynamic thermal emission control has attracted considerable attention in the fields of radiative cooling, 1 , 2 , 3 , 4 adaptive camouflage, 5 , 6 , 7 , 8 , 9 thermostats, 10 , 11 thermochromic smart windows, 12 , 13 , 14 spacecraft thermal control 15 , 16 and thermophotovoltaic cells. 17 , 18 , 19 Among various dynamic thermal emission devices, the VO 2 -based dynamic emitter is a promising representative, which undergoes a reversible metal-to-insulator transition (MIT) at a critical temperature T c (68°C for intrinsic VO 2 ). 20 , 21 The occurrence of MIT is always accompanied by a dramatic change in the optical properties, which transforms the phase-change material from an infrared lossless “insulator state” ( T < T c ) to an infrared lossy “metallic state” ( T > T c ).…”

New insight into piezoelectric energy harvesting with mechanical and electrical nonlinearities

“…In decades' developments, regarding these three parts, different system enhancement strategies have been proposed. Firstly, the frequency-tuning technique [2], multi-modal configuration [3], frequency-up conversion [4,5] and nonlinear design [6,7] have been employed to amplify the mechanical excitation input. It was shown that the nonlinear piezoelectric energy harvester with a purely resistive load offers a broader bandwidth [7].…”