Thermodynamic analysis of thermophotovoltaic efficiency and power density tradeoffs

Baldasaro, P.F.; Raynolds, James E.; Charache, G.W.; DePoy, D.M.; Ballinger, C.T.; Donovan, Timothy J.; Borrego, J.M.

doi:10.1063/1.1344580

Cited by 85 publications

(51 citation statements)

References 14 publications

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“…Because of it, the system has a very low electric power density (Fig. 7), which reveals the existence of a trade-off between efficiency and power density (already identified [7]) and represents one of the fundamental barriers to reaching high efficiency in these kinds of STPV systems: the maximum efficiency is obtained when the electric power density approaches zero.…”

Section: The Ideal Stpv Systemmentioning

confidence: 99%

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Detailed balance analysis of solar thermophotovoltaic systems made up of single junction photovoltaic cells and broadband thermal emitters

Datas

Algora

2010

Solar Energy Materials and Solar Cells

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Keywords:Solar thermophotovoltaic system Concentration Optical cavity Spectral control Selective absorber This paper presents a detailed balance analysis of a solar thermophotovoltaic system comprising an optical concentrator, a cut-off broad band absorber and emitter, and single junction photovoltaic cells working at the radiative limit with an integrated back-side reflector in a configuration in which the cells enclose the emitter to form an optical cavity. The analysis includes the effect of multiple variables on the system performance (efficiency and electrical power density), such as the concentration factor, the emitter-to-absorber area ratio, the absorber and emitter cut-off energies, the semiconductor band-gap energy and the voltage of the cells. Furthermore, the effect of optical losses within the cavity such as those attributed to a back-side reflector with reflectivity lower than one or to a semi-open optical cavity is also included. One of our main conclusions is that for a planar system configuration (the emitter, the cells and the absorber have the same area) the combination of low concentration and a spectrally selective absorber provides the highest system efficiencies. The efficiency limit of this kind of systems is 45.3%, which exceeds the Shockley-Queisser limit of 40.8% (obtained for a single junction solar cell, directly illuminated by the sun, working under maximum concentration and with an optimized band-gap). This system also has the great benefit of requiring a very low concentration factor of 4.4 suns.

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Section: The Ideal Stpv Systemmentioning

confidence: 99%

“…Nevertheless, at very low band-gap energies, V mpp shows an unexpected increase, which must be attributed to a sharp increase in the open-circuit voltage (Fig. 14) that appears due to the increase in the carriers generation rate at low band-gap energies [7].…”

Section: Pv Cells Voltagementioning

confidence: 99%

Detailed balance analysis of solar thermophotovoltaic systems made up of single junction photovoltaic cells and broadband thermal emitters

Datas

Algora

2010

Solar Energy Materials and Solar Cells

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“…In addition, these figures of merit are valid for any spectral control method or combination of methods and have been shown to correlate with the measured in-cavity efficiency and power density of a combined TPV cell and spectral control configuration [3,4]. Examination of Eq.…”

Section: Figures Of Merit For Tpv Spectral Controlmentioning

confidence: 99%

Thermophotovoltaic Spectral Control

DePoy¹,

Fourspring²,

Brown³

et al. 2004

2nd International Energy Conversion Engineering Conference

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Spectral control is a key technology for thermophotovoltaic (TPV) direct energy conversion systems because only a fraction (typically less than 25%) of the incident thermal radiation has energy exceeding the diode bandgap energy, E g , and can thus be converted to electricity. The goal for TPV spectral control in most applications is twofold:1. Maximize TPV efficiency by minimizing transfer of low energy, below bandgap photons from the radiator to the TPV diode. 2. Maximize TPV surface power density by maximizing transfer of high energy, above bandgap photons from the radiator to the TPV diode.TPV spectral control options include: front surface filters (e.g. interference filters, plasma filters, interference/plasma tandem filters, and frequency selective surfaces), back surface reflectors, and wavelength selective radiators. System analysis shows that spectral performance dominates diode performance in any practical TPV system, and that low bandgap diodes enable both higher efficiency and power density when spectral control limitations are considered. Lockheed Martin has focused its efforts on front surface tandem filters which have achieved spectral efficiencies of ~83% for E g = 0.52 eV and ~76% for E g = 0.60 eV for a 950 o C radiator temperature.

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“…This fact indicates that PV diodes with low band gap energy (<1 eV) should be used in STPV systems to ensure good overlap between diode absorption band edge and a selective emission spectrum. Combined with concentrated sunlight, STPV systems may exceed the Shockley-Queisser limit [28,29,117].…”

Section: Pv Diodes Options and Performancementioning

confidence: 99%

Solar thermophotovoltaics: reshaping the solar spectrum

et al. 2016

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Abstract:Recently, there has been increasing interest in utilizing solar thermophotovoltaics (STPV) to convert sunlight into electricity, given their potential to exceed the Shockley-Queisser limit. Encouragingly, there have also been several recent demonstrations of improved systemlevel efficiency as high as 6.2%. In this work, we review prior work in the field, with particular emphasis on the role of several key principles in their experimental operation, performance, and reliability. In particular, for the problem of designing selective solar absorbers, we consider the trade-off between solar absorption and thermal losses, particularly radiative and convective mechanisms. For the selective thermal emitters, we consider the tradeoff between emission at critical wavelengths and parasitic losses. Then for the thermophotovoltaic (TPV) diodes, we consider the trade-off between increasing the potential short-circuit current, and maintaining a reasonable opencircuit voltage. This treatment parallels the historic development of the field, but also connects early insights with recent developments in adjacent fields. With these various components connecting in multiple ways, a system-level end-to-end modeling approach is necessary for a comprehensive understanding and appropriate improvement of STPV systems. This approach will ultimately allow researchers to design STPV systems capable of exceeding recently demonstrated efficiency values.

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Thermodynamic analysis of thermophotovoltaic efficiency and power density tradeoffs

Cited by 85 publications

References 14 publications

Detailed balance analysis of solar thermophotovoltaic systems made up of single junction photovoltaic cells and broadband thermal emitters

Detailed balance analysis of solar thermophotovoltaic systems made up of single junction photovoltaic cells and broadband thermal emitters

Thermophotovoltaic Spectral Control

Solar thermophotovoltaics: reshaping the solar spectrum

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