1.
R Peibst; M Rienäcker; Y Larionova; N Folchert; F Haase; C Hollemann; S Wolter; J Krügener; P Bayerl; J Bayer; M Dzinnik; R J Haug; R Brendel
Towards 28 %-efficient Si single-junction solar cells with better passivating POLO junctions and photonic crystals Artikel Geplante Veröffentlichung
In: Solar Energy Materials and Solar Cells, S. 111560, Geplante Veröffentlichung, ISSN: 0927-0248.
@article{Peibst2022,
title = {Towards 28 %-efficient Si single-junction solar cells with better passivating POLO junctions and photonic crystals},
author = {R Peibst and M Rienäcker and Y Larionova and N Folchert and F Haase and C Hollemann and S Wolter and J Krügener and P Bayerl and J Bayer and M Dzinnik and R J Haug and R Brendel},
doi = {10.1016/j.solmat.2021.111560},
issn = {0927-0248},
year = {2022},
date = {2022-01-20},
urldate = {2022-01-01},
journal = {Solar Energy Materials and Solar Cells},
pages = {111560},
abstract = {We conduct numerical device simulations to study to what extend poly-Si on oxide (POLO)2 IBC solar cells can be optimized. In particular, we evaluate the benefit of the concept of photonic crystals (PCs) for “standard” cell thicknesses compatible with industrial wafer handling. We find that for our current surface passivation quality, implementing PCs and decreasing the wafer thickness down to 15 μm would increase the efficiency by „only“ 1% absolute due to limiting surface recombination losses. We deduce a high c-Si/SiOx interface state density Dit of 2.9 × 1012 eV−1cm−2 by analyzing special two-terminal IV measurements on small pads that contact the intact interfacial oxide between pinholes with our MarcoPOLO model. Consequently, we improve the hydrogenation process of our POLO junctions by an Al2O3/SiNx/Al2O3 rear-side dielectric layer stack. For n-type POLO (p-type POLO) J0 is reduced from 4 (10) fA/cm2 down to 0.5 ± 0.3 (3.3 ± 0.7) fA/cm2. For this improved surface passivation, our numerical device simulations predict an efficiency potential of 29.1% (27.8%) for POLO2 IBC cells with (without) PCs for a standard thickness of 150 μm. This shows that the “practical limit” for Si solar cells with poly-Si on oxide-based passivating contact schemes is above 27%, and, in general, that the efficiency potential of Si single-junction cells is still far from being exhausted. The first implementation of the improved POLO junctions into cell precursors confirms the predicted improvement on the level of suns - implied open-circuit voltage curves.},
keywords = {},
pubstate = {forthcoming},
tppubtype = {article}
}
We conduct numerical device simulations to study to what extend poly-Si on oxide (POLO)2 IBC solar cells can be optimized. In particular, we evaluate the benefit of the concept of photonic crystals (PCs) for “standard” cell thicknesses compatible with industrial wafer handling. We find that for our current surface passivation quality, implementing PCs and decreasing the wafer thickness down to 15 μm would increase the efficiency by „only“ 1% absolute due to limiting surface recombination losses. We deduce a high c-Si/SiOx interface state density Dit of 2.9 × 1012 eV−1cm−2 by analyzing special two-terminal IV measurements on small pads that contact the intact interfacial oxide between pinholes with our MarcoPOLO model. Consequently, we improve the hydrogenation process of our POLO junctions by an Al2O3/SiNx/Al2O3 rear-side dielectric layer stack. For n-type POLO (p-type POLO) J0 is reduced from 4 (10) fA/cm2 down to 0.5 ± 0.3 (3.3 ± 0.7) fA/cm2. For this improved surface passivation, our numerical device simulations predict an efficiency potential of 29.1% (27.8%) for POLO2 IBC cells with (without) PCs for a standard thickness of 150 μm. This shows that the “practical limit” for Si solar cells with poly-Si on oxide-based passivating contact schemes is above 27%, and, in general, that the efficiency potential of Si single-junction cells is still far from being exhausted. The first implementation of the improved POLO junctions into cell precursors confirms the predicted improvement on the level of suns - implied open-circuit voltage curves.
2.
L Helmich; D C Walter; T Pernau; J Schmidt
In: IEEE Journal of Photovoltaics, 12 (1), S. 198-203, 2022.
@article{Helmich2022,
title = {Carrier Lifetime Stability of Boron-Doped Czochralski-Grown Silicon Materials for Years After Regeneration in an Industrial Belt Furnace},
author = {L Helmich and D C Walter and T Pernau and J Schmidt},
doi = {10.1109/JPHOTOV.2021.3116019},
year = {2022},
date = {2022-01-01},
urldate = {2021-10-26},
journal = {IEEE Journal of Photovoltaics},
volume = {12},
number = {1},
pages = {198-203},
abstract = {We examine the long-term stability of the carrier lifetime in boron-doped Czochralski-grown silicon materials with different boron and oxygen concentrations, which were regenerated in an industrial belt furnace. After firing and subsequent regeneration in an industrial conveyor-belt furnace, the silicon samples are exposed to long-term illumination at an intensity of 0.1 suns and a sample temperature of about 30 °C for more than two years. After regeneration, we observe a minor re-degradation (30–72% reduced compared to the degradation observed without regeneration step). We attribute this re-degradation to a non-completed regeneration within the belt furnace due to the short regeneration period. Our results show that the industrial process consisting of firing with subsequent regeneration in the same unit is very effective for industrially relevant silicon materials. Typical industrial silicon wafers with a resistivity of (1.75 ± 0.03) Ωcm and an interstitial oxygen concentration of (6.9 ± 0.3) × 1017 cm–3 show lifetimes larger than 2 ms after regeneration and two years of light exposure.},
keywords = {},
pubstate = {published},
tppubtype = {article}
}
We examine the long-term stability of the carrier lifetime in boron-doped Czochralski-grown silicon materials with different boron and oxygen concentrations, which were regenerated in an industrial belt furnace. After firing and subsequent regeneration in an industrial conveyor-belt furnace, the silicon samples are exposed to long-term illumination at an intensity of 0.1 suns and a sample temperature of about 30 °C for more than two years. After regeneration, we observe a minor re-degradation (30–72% reduced compared to the degradation observed without regeneration step). We attribute this re-degradation to a non-completed regeneration within the belt furnace due to the short regeneration period. Our results show that the industrial process consisting of firing with subsequent regeneration in the same unit is very effective for industrially relevant silicon materials. Typical industrial silicon wafers with a resistivity of (1.75 ± 0.03) Ωcm and an interstitial oxygen concentration of (6.9 ± 0.3) × 1017 cm–3 show lifetimes larger than 2 ms after regeneration and two years of light exposure.
3.
P Leibbrandt; F Giovannetti; T Schabbach; U Jordan
Improved calculation approach of the heat transfer in inclined insulating gas layers Artikel
In: Solar Energy, 231 , S. 252-261, 2022, ISSN: 0038-092X.
@article{Leibbrandt2022b,
title = {Improved calculation approach of the heat transfer in inclined insulating gas layers},
author = {P Leibbrandt and F Giovannetti and T Schabbach and U Jordan},
doi = {10.1016/j.solener.2021.10.052},
issn = {0038-092X},
year = {2022},
date = {2022-01-01},
journal = {Solar Energy},
volume = {231},
pages = {252-261},
abstract = {Known calculation approaches for the determination of internal natural convection in inclined plane-parallel insulating gas layers have been developed above the critical Rayleigh number in the post-conductive regime. The most well-known correlation function which is used in solar thermal collector design assumes pure conduction below the critical Rayleigh number. However, recent measurements on insulating gas layers in standard flat-plate and insulating glass solar collectors show that this assumption leads to an underestimation of the heat transfer between the absorber and the front cover of the solar collector. In the presented study measurements on insulating glazing were carried out. A correction function is proposed which characterizes the heat transport processes below the critical Rayleigh number taking into account for convective heat transfer. The dependent variable of the correction function is the aspect ratio of the insulating gas layer, which has a significant influence on the flow regimes and thus the heat transport phenomena that occur.},
keywords = {},
pubstate = {published},
tppubtype = {article}
}
Known calculation approaches for the determination of internal natural convection in inclined plane-parallel insulating gas layers have been developed above the critical Rayleigh number in the post-conductive regime. The most well-known correlation function which is used in solar thermal collector design assumes pure conduction below the critical Rayleigh number. However, recent measurements on insulating gas layers in standard flat-plate and insulating glass solar collectors show that this assumption leads to an underestimation of the heat transfer between the absorber and the front cover of the solar collector. In the presented study measurements on insulating glazing were carried out. A correction function is proposed which characterizes the heat transport processes below the critical Rayleigh number taking into account for convective heat transfer. The dependent variable of the correction function is the aspect ratio of the insulating gas layer, which has a significant influence on the flow regimes and thus the heat transport phenomena that occur.
4.
T Niewelt; B Steinhauser; A Richter; B Veith-Wolf; A Fell; B Hammann; N E Grant; L Black; J Tan; A Youssef; J D Murphy; J Schmidt; M C Schubert; S W Glunz
Reassessment of the intrinsic bulk recombination in crystalline silicon Artikel
In: Solar Energy Materials and Solar Cells, 235 , S. 111467, 2022, ISSN: 0927-0248.
@article{Niewelt2022b,
title = {Reassessment of the intrinsic bulk recombination in crystalline silicon},
author = {T Niewelt and B Steinhauser and A Richter and B Veith-Wolf and A Fell and B Hammann and N E Grant and L Black and J Tan and A Youssef and J D Murphy and J Schmidt and M C Schubert and S W Glunz},
doi = {10.1016/j.solmat.2021.111467},
issn = {0927-0248},
year = {2022},
date = {2022-01-01},
journal = {Solar Energy Materials and Solar Cells},
volume = {235},
pages = {111467},
abstract = {Characterisation and optimization of next-generation silicon solar cell concepts rely on an accurate knowledge of intrinsic charge carrier recombination in crystalline silicon. Reports of measured lifetimes exceeding the previous accepted parameterisation of intrinsic recombination indicate an overestimation of this recombination in certain injection regimes and hence the need for revision. In this work, twelve high-quality silicon sample sets covering a wide doping range are fabricated using state-of-the-art processing routes in order to permit an accurate assessment of intrinsic recombination based on wafer thickness variation. Special care is taken to mitigate extrinsic recombination due to bulk contamination or at the wafer surfaces. The combination of the high-quality samples with refined sample characterisation and lifetime measurements enables a much higher level of accuracy to be achieved compared to previous studies. We observe that reabsorption of luminescence photons inside the sample must be accounted for to achieve a precise description of radiative recombination. With this effect taken into account, we extract the lifetime limitation due to Auger recombination. We find that the extracted Auger recombination rate can accurately be parameterized using a physically motivated equation based on Coulomb-enhanced Auger recombination for all doping and injection conditions relevant for silicon-based photovoltaics. The improved accuracy of data description obtained with the model suggests that our new parameterisation is more consistent with the actual recombination process than previous models. Due to notable changes in Auger recombination predicted for moderate injection, we further revise the fundamental limiting power conversion efficiency for a single-junction crystalline silicon solar cell to 29.4%, which is within 0.1%abs compared to other recent assessments.},
keywords = {},
pubstate = {published},
tppubtype = {article}
}
Characterisation and optimization of next-generation silicon solar cell concepts rely on an accurate knowledge of intrinsic charge carrier recombination in crystalline silicon. Reports of measured lifetimes exceeding the previous accepted parameterisation of intrinsic recombination indicate an overestimation of this recombination in certain injection regimes and hence the need for revision. In this work, twelve high-quality silicon sample sets covering a wide doping range are fabricated using state-of-the-art processing routes in order to permit an accurate assessment of intrinsic recombination based on wafer thickness variation. Special care is taken to mitigate extrinsic recombination due to bulk contamination or at the wafer surfaces. The combination of the high-quality samples with refined sample characterisation and lifetime measurements enables a much higher level of accuracy to be achieved compared to previous studies. We observe that reabsorption of luminescence photons inside the sample must be accounted for to achieve a precise description of radiative recombination. With this effect taken into account, we extract the lifetime limitation due to Auger recombination. We find that the extracted Auger recombination rate can accurately be parameterized using a physically motivated equation based on Coulomb-enhanced Auger recombination for all doping and injection conditions relevant for silicon-based photovoltaics. The improved accuracy of data description obtained with the model suggests that our new parameterisation is more consistent with the actual recombination process than previous models. Due to notable changes in Auger recombination predicted for moderate injection, we further revise the fundamental limiting power conversion efficiency for a single-junction crystalline silicon solar cell to 29.4%, which is within 0.1%abs compared to other recent assessments.
5.
C Hollemann; M Rienäcker; A Soeriyadi; C Madumelu; F Haase; J Krügener; B Hallam; R Brendel; R Peibst
Firing stability of tube furnace-annealed n-type poly-Si on oxide junctions Artikel
In: Progress in Photovoltaics: Research and Applications, 30 (1), S. 49-64, 2022.
@article{Hollemann2022,
title = {Firing stability of tube furnace-annealed n-type poly-Si on oxide junctions},
author = {C Hollemann and M Rienäcker and A Soeriyadi and C Madumelu and F Haase and J Krügener and B Hallam and R Brendel and R Peibst},
doi = {10.1002/pip.3459},
year = {2022},
date = {2022-01-01},
journal = {Progress in Photovoltaics: Research and Applications},
volume = {30},
number = {1},
pages = {49-64},
abstract = {Stability of the passivation quality of poly-Si on oxide junctions against the conventional mainstream high-temperature screen-print firing processes is highly desirable and also expected since the poly-Si on oxide preparation occurs at higher temperatures and for longer durations than firing. We measure recombination current densities (J0) and interface state densities (Dit) of symmetrical samples with n-type poly-Si contacts before and after firing. Samples without a capping dielectric layer show a significant deterioration of the passivation quality during firing. The Dit values are (3 ± 0.2) × 1011 and (8 ± 2) × 1011 eV/cm2 when fired at 620°C and 900°C, respectively. The activation energy in an Arrhenius fit of Dit versus the firing temperature is 0.30 ± 0.03 eV. This indicates that thermally induced desorption of hydrogen from SiH bonds at the poly-Si/SiOx interface is not the root cause of depassivation. Postfiring annealing at 425°C can improve the passivation again. Samples with SiNx capping layers show an increase in J0 up to about 100 fA/cm2 by firing, which can be attributed to blistering and is not reversed by annealing at 425°C. On the other hand, blistering does not occur in poly-Si samples capped with AlOx layers or AlOx/SiNy stacks, and J0 values of 2–5 fA/cm2 can be achieved after firing. Those findings suggest that a combination of two effects might be the root cause of the increase in J0 and Dit: thermal stress at the SiOz interface during firing and blistering. Blistering is presumed to occur when the hydrogen concentration in the capping layers exceeds a certain level.},
keywords = {},
pubstate = {published},
tppubtype = {article}
}
Stability of the passivation quality of poly-Si on oxide junctions against the conventional mainstream high-temperature screen-print firing processes is highly desirable and also expected since the poly-Si on oxide preparation occurs at higher temperatures and for longer durations than firing. We measure recombination current densities (J0) and interface state densities (Dit) of symmetrical samples with n-type poly-Si contacts before and after firing. Samples without a capping dielectric layer show a significant deterioration of the passivation quality during firing. The Dit values are (3 ± 0.2) × 1011 and (8 ± 2) × 1011 eV/cm2 when fired at 620°C and 900°C, respectively. The activation energy in an Arrhenius fit of Dit versus the firing temperature is 0.30 ± 0.03 eV. This indicates that thermally induced desorption of hydrogen from SiH bonds at the poly-Si/SiOx interface is not the root cause of depassivation. Postfiring annealing at 425°C can improve the passivation again. Samples with SiNx capping layers show an increase in J0 up to about 100 fA/cm2 by firing, which can be attributed to blistering and is not reversed by annealing at 425°C. On the other hand, blistering does not occur in poly-Si samples capped with AlOx layers or AlOx/SiNy stacks, and J0 values of 2–5 fA/cm2 can be achieved after firing. Those findings suggest that a combination of two effects might be the root cause of the increase in J0 and Dit: thermal stress at the SiOz interface during firing and blistering. Blistering is presumed to occur when the hydrogen concentration in the capping layers exceeds a certain level.
6.
John F. Geisz; William E. McMahon; Jeronimo Buencuerpo; Michelle S. Young; Michael Rienäcker; Adele C. Tamboli; Emily L. Warren
Characterization of multiterminal tandem photovoltaic devices and their subcell coupling Artikel
In: Cell Reports Physical Science, 2 (12), S. 100677, 2021, ISSN: 2666-3864.
@article{Geisz2021,
title = {Characterization of multiterminal tandem photovoltaic devices and their subcell coupling},
author = {John F. Geisz and William E. McMahon and Jeronimo Buencuerpo and Michelle S. Young and Michael Rienäcker and Adele C. Tamboli and Emily L. Warren},
doi = {10.1016/j.xcrp.2021.100677},
issn = {2666-3864},
year = {2021},
date = {2021-12-22},
urldate = {2021-01-01},
journal = {Cell Reports Physical Science},
volume = {2},
number = {12},
pages = {100677},
abstract = {Three-terminal (3T) and four-terminal (4T) tandem photovoltaic (PV) devices using various materials have been increasingly reported in the literature, but measurement standards are lacking. Here, multiterminal devices measured as functions of two load variables are characterized unambiguously as functions of three device voltages or currents on hexagonal plots. We demonstrate these measurement techniques using two GaInP/GaAs tandem solar cells, with a middle contact between the two subcells, as example 3T devices with both series-connected and reverse-connected subcells. Coupling mechanisms between the subcells are quantified within the context of a simple equivalent optoelectronic circuit. Electrical and optical coupling mechanisms are most clearly revealed using coupled dark measurements. These measurements are sensitive enough to observe very small luminescent coupling from the bottom subcell to the top subcell in the prototype 3T device. Quick simplified measurement techniques are also discussed within the context of the complete characterization.},
keywords = {},
pubstate = {published},
tppubtype = {article}
}
Three-terminal (3T) and four-terminal (4T) tandem photovoltaic (PV) devices using various materials have been increasingly reported in the literature, but measurement standards are lacking. Here, multiterminal devices measured as functions of two load variables are characterized unambiguously as functions of three device voltages or currents on hexagonal plots. We demonstrate these measurement techniques using two GaInP/GaAs tandem solar cells, with a middle contact between the two subcells, as example 3T devices with both series-connected and reverse-connected subcells. Coupling mechanisms between the subcells are quantified within the context of a simple equivalent optoelectronic circuit. Electrical and optical coupling mechanisms are most clearly revealed using coupled dark measurements. These measurements are sensitive enough to observe very small luminescent coupling from the bottom subcell to the top subcell in the prototype 3T device. Quick simplified measurement techniques are also discussed within the context of the complete characterization.
7.
G Wetzel; L Salomon; J Krügener; D Bredemeier; R Peibst
High time resolution measurement of solar irradiance onto driving car body for vehicle integrated photovoltaics Artikel Geplante Veröffentlichung
In: Progress in Photovoltaics: Research and Applications, Geplante Veröffentlichung.
@article{Wetzel2021,
title = {High time resolution measurement of solar irradiance onto driving car body for vehicle integrated photovoltaics},
author = {G Wetzel and L Salomon and J Krügener and D Bredemeier and R Peibst},
doi = {10.1002/pip.3526},
year = {2021},
date = {2021-12-20},
journal = {Progress in Photovoltaics: Research and Applications},
abstract = {Abstract Vehicle integrated photovoltaic (VIPV) systems have much different requirements on maximum power tracking compared to stationary setups. The occurrence of fast changes between full irradiance and shading are demanding. To evaluate the specific impact of these conditions on the specifications of VIPV systems, we conduct high resolution measurements of the incident irradiance onto a car body while driving. We investigate the influence of environmental conditions like weather, season and building density in an urban environment on measured irradiance on the roof and the sides of a vehicle. We find that weather conditions have the highest impact on the measured irradiance on the roof, while the relative irradiance on the side depends more heavily on the season. We also find that changes in irradiance occur predominantly at frequencies below 1 Hz, but changes with 100 Hz or more can occur in certain situations, with a tendency toward higher frequencies for sunny weather. This must be considered in maximum power point tracker design.},
keywords = {},
pubstate = {forthcoming},
tppubtype = {article}
}
Abstract Vehicle integrated photovoltaic (VIPV) systems have much different requirements on maximum power tracking compared to stationary setups. The occurrence of fast changes between full irradiance and shading are demanding. To evaluate the specific impact of these conditions on the specifications of VIPV systems, we conduct high resolution measurements of the incident irradiance onto a car body while driving. We investigate the influence of environmental conditions like weather, season and building density in an urban environment on measured irradiance on the roof and the sides of a vehicle. We find that weather conditions have the highest impact on the measured irradiance on the roof, while the relative irradiance on the side depends more heavily on the season. We also find that changes in irradiance occur predominantly at frequencies below 1 Hz, but changes with 100 Hz or more can occur in certain situations, with a tendency toward higher frequencies for sunny weather. This must be considered in maximum power point tracker design.
8.
F Hüsing
Einrohrzirkulation in Wärmepumpensystemen Vortrag
Holzminden, Germany, 17.12.2021, (Sachverständigen-Forum des VSHK (Verein der Vereidigten Sachverständigen der SHK-Handwerke Niedersachsen e.V.)).
@misc{Hüsing2021d,
title = {Einrohrzirkulation in Wärmepumpensystemen},
author = {F Hüsing},
year = {2021},
date = {2021-12-17},
address = {Holzminden, Germany},
note = {Sachverständigen-Forum des VSHK (Verein der Vereidigten Sachverständigen der SHK-Handwerke Niedersachsen e.V.)},
keywords = {},
pubstate = {published},
tppubtype = {presentation}
}
9.
M Rienäcker; Y Larionova; J Krügener; S Wolter; R Brendel; R Peibst
In: EPJ Photovoltaics, 12 , S. 6, 2021.
@article{Rienäcker2021d,
title = {Rear side dielectrics on interdigitating p+-(i)-n+ back-contact solar cells - hydrogenation vs. charge effects},
author = {M Rienäcker and Y Larionova and J Krügener and S Wolter and R Brendel and R Peibst},
doi = {10.1051/epjpv/2021007},
year = {2021},
date = {2021-12-15},
urldate = {2021-01-01},
journal = {EPJ Photovoltaics},
volume = {12},
pages = {6},
abstract = {Polysilicon-on-oxide (POLO) passivating contacts and interdigitated back-contact (IBC) cell technologies have recently attracted a lot of interest as candidates for the implementation in the next generation of solar cells. An IBC cell with POLO junctions for both polarities − a POLO2-IBC cell − has to electrically isolate the highly defective p+ and n+ poly-Si regions on the rear side of the cell to avoid parasitic recombination. Inserting an initially undoped, intrinsic (i) region between the p+ and n+ poly-Si regions was demonstrated to successfully prevent the parasitic recombination in the transition region of ISFH's 26.1%-efficient POLO2-IBC cell. In order to further improve the conversion efficiency towards 27%, we apply hydrogen-donating dielectric layer stacks to the p+-(i)-n+ POLO interdigitating rear side to enhance the passivation quality of the POLO junctions. We indeed show a significant improvement of POLO junctions on symmetrical full-area homogenously doped reference samples, but when we apply a hydrogen-donating layer stack on the p+-(i)-n+ POLO interdigitating rear side, we observe a strong degradation in the performance of the POLO2-IBC cell. We attribute this to the formation of a conductive channel between the p+ and n+ poly-Si regions due to the strong negative charge density of the hydrogen-donating layer stack.},
keywords = {},
pubstate = {published},
tppubtype = {article}
}
Polysilicon-on-oxide (POLO) passivating contacts and interdigitated back-contact (IBC) cell technologies have recently attracted a lot of interest as candidates for the implementation in the next generation of solar cells. An IBC cell with POLO junctions for both polarities − a POLO2-IBC cell − has to electrically isolate the highly defective p+ and n+ poly-Si regions on the rear side of the cell to avoid parasitic recombination. Inserting an initially undoped, intrinsic (i) region between the p+ and n+ poly-Si regions was demonstrated to successfully prevent the parasitic recombination in the transition region of ISFH's 26.1%-efficient POLO2-IBC cell. In order to further improve the conversion efficiency towards 27%, we apply hydrogen-donating dielectric layer stacks to the p+-(i)-n+ POLO interdigitating rear side to enhance the passivation quality of the POLO junctions. We indeed show a significant improvement of POLO junctions on symmetrical full-area homogenously doped reference samples, but when we apply a hydrogen-donating layer stack on the p+-(i)-n+ POLO interdigitating rear side, we observe a strong degradation in the performance of the POLO2-IBC cell. We attribute this to the formation of a conductive channel between the p+ and n+ poly-Si regions due to the strong negative charge density of the hydrogen-donating layer stack.
10.
H Fischer; R Peibst
VIPV demonstration for light commercial vehicles: Test drives and energy flow analysis Vortrag
Online Event, 15.12.2021, (31st International PV Science and Engineering Conference (PVSEC-31)).
@misc{Fischer2021b,
title = {VIPV demonstration for light commercial vehicles: Test drives and energy flow analysis},
author = {H Fischer and R Peibst},
year = {2021},
date = {2021-12-15},
address = {Online Event},
note = {31st International PV Science and Engineering Conference (PVSEC-31)},
keywords = {},
pubstate = {published},
tppubtype = {presentation}
}
11.
H Fischer; R Peibst
Test drives with an electrically driven VIPV LCV demonstrator vehicle: Range extension and energy flow analysis from low to high voltage level Vortrag
Online Event, 08.12.2021, (PVinMotion 2021).
@misc{Fischer2021,
title = {Test drives with an electrically driven VIPV LCV demonstrator vehicle: Range extension and energy flow analysis from low to high voltage level},
author = {H Fischer and R Peibst},
year = {2021},
date = {2021-12-08},
address = {Online Event},
note = {PVinMotion 2021},
keywords = {},
pubstate = {published},
tppubtype = {presentation}
}
12.
M Rienäcker; V Titova; J Schmidt; R Peibst; R Brendel
Selectivity and extraction efficiency of solar cell contacts: Comparing Different Definitions and Their Experimental Quantification Vortrag
Online Event, 07.12.2021, (MRS Fall Meeting 2021).
@misc{Rienäcker2021e,
title = {Selectivity and extraction efficiency of solar cell contacts: Comparing Different Definitions and Their Experimental Quantification},
author = {M Rienäcker and V Titova and J Schmidt and R Peibst and R Brendel},
year = {2021},
date = {2021-12-07},
address = {Online Event},
note = {MRS Fall Meeting 2021},
keywords = {},
pubstate = {published},
tppubtype = {presentation}
}
13.
J Schumann; B Schiebler; F Giovannetti
Performance Evaluation of an Evacuated Tube Collector with a Low-Cost Diffuse Reflector Artikel
In: Energies, 14 (24), 2021, ISSN: 1996-1073.
@article{Schumann2021,
title = {Performance Evaluation of an Evacuated Tube Collector with a Low-Cost Diffuse Reflector},
author = {J Schumann and B Schiebler and F Giovannetti},
doi = {10.3390/en14248209},
issn = {1996-1073},
year = {2021},
date = {2021-12-01},
journal = {Energies},
volume = {14},
number = {24},
abstract = {In order to increase the overall solar energy gain of evacuated tube collectors, rear-side reflectors are used. In this way, the otherwise unused incident radiation between the tubes can be reflected back to the absorber, and the performance of the collector can be improved. In this paper, the use of a low-cost, diffusely reflecting, trapezoidal roof covering made from a galvanized metal sheet is investigated and compared to a high-quality, specularly reflecting plane reflector made of aluminum. For this purpose, ray-tracing analysis and TRNSYS simulations were carried out. In the ray-tracing analysis, the experimentally determined zero-loss collector efficiency η0 as well as the incident angle modifiers for each reflector can be reproduced with an error lower than 7.5%. Thermal system simulations show that the performance of both reflectors is comparable. The use of the low-cost reflector leads to an increase in annual collector output of around 30% compared to an increase with the specular reflector of around 33%. Considering a typical domestic hot water system, both reflectors enable an increase in the solar annual yield of approx. 11%.},
keywords = {},
pubstate = {published},
tppubtype = {article}
}
In order to increase the overall solar energy gain of evacuated tube collectors, rear-side reflectors are used. In this way, the otherwise unused incident radiation between the tubes can be reflected back to the absorber, and the performance of the collector can be improved. In this paper, the use of a low-cost, diffusely reflecting, trapezoidal roof covering made from a galvanized metal sheet is investigated and compared to a high-quality, specularly reflecting plane reflector made of aluminum. For this purpose, ray-tracing analysis and TRNSYS simulations were carried out. In the ray-tracing analysis, the experimentally determined zero-loss collector efficiency η0 as well as the incident angle modifiers for each reflector can be reproduced with an error lower than 7.5%. Thermal system simulations show that the performance of both reflectors is comparable. The use of the low-cost reflector leads to an increase in annual collector output of around 30% compared to an increase with the specular reflector of around 33%. Considering a typical domestic hot water system, both reflectors enable an increase in the solar annual yield of approx. 11%.
14.
J Krügener; M Rienäcker; S Schäfer; M Sanchez; S Wolter; R Brendel; S John; H J Osten; R Peibst
Photonic crystals for highly efficient silicon single junction solar cells Artikel
In: Solar Energy Materials and Solar Cells, 233 , S. 111337, 2021, ISSN: 0927-0248.
@article{Krügener2021b,
title = {Photonic crystals for highly efficient silicon single junction solar cells},
author = {J Krügener and M Rienäcker and S Schäfer and M Sanchez and S Wolter and R Brendel and S John and H J Osten and R Peibst},
doi = {10.1016/j.solmat.2021.111337},
issn = {0927-0248},
year = {2021},
date = {2021-12-01},
journal = {Solar Energy Materials and Solar Cells},
volume = {233},
pages = {111337},
abstract = {The maximum achievable silicon single junction solar cell efficiency is limited by intrinsic recombination and by its limited capability of absorbing sun light. For Lambertian light trapping the maximum theoretical solar cell efficiency is around 29.5%. Recently a new approach for light trapping has been proposed for silicon photovoltaics. Highly regular structures with a size in the range of the wavelengths of the incident light act as so-called photonic crystals. Such structures allow wave-interference light trapping beyond the Lambertian limit. Applying these photonic crystals to silicon solar cells can help to reduce the absorber thickness and thus to minimizing the unavoidable intrinsic recombination. From a simulation study, we can conclude that 31.6% is the maximum possible single junction solar cell efficiency for a 15 μm-thin substrate. Furthermore, we present a process flow for the preparation of regular inverted pyramid structure, that acts as photonic crystal. Finally, regular inverted pyramid structures are prepared on polished and shiny-etched, i. e. on surfaces with a certain roughness, substrates. Surface passivation of these structured surfaces shows as good lifetimes as on conventional randomly pyramid textured surface. Excellent total saturation current densities on asymmetric samples of 4 ± 2 fA/cm2 for n-type and of 4.5 ± 2.2 fA/cm2 on p-type substrates are obtained.},
keywords = {},
pubstate = {published},
tppubtype = {article}
}
The maximum achievable silicon single junction solar cell efficiency is limited by intrinsic recombination and by its limited capability of absorbing sun light. For Lambertian light trapping the maximum theoretical solar cell efficiency is around 29.5%. Recently a new approach for light trapping has been proposed for silicon photovoltaics. Highly regular structures with a size in the range of the wavelengths of the incident light act as so-called photonic crystals. Such structures allow wave-interference light trapping beyond the Lambertian limit. Applying these photonic crystals to silicon solar cells can help to reduce the absorber thickness and thus to minimizing the unavoidable intrinsic recombination. From a simulation study, we can conclude that 31.6% is the maximum possible single junction solar cell efficiency for a 15 μm-thin substrate. Furthermore, we present a process flow for the preparation of regular inverted pyramid structure, that acts as photonic crystal. Finally, regular inverted pyramid structures are prepared on polished and shiny-etched, i. e. on surfaces with a certain roughness, substrates. Surface passivation of these structured surfaces shows as good lifetimes as on conventional randomly pyramid textured surface. Excellent total saturation current densities on asymmetric samples of 4 ± 2 fA/cm2 for n-type and of 4.5 ± 2.2 fA/cm2 on p-type substrates are obtained.
15.
R Niepelt; B Engel; F Giovannetti; N Gräfer; M Henke; S Holler; L Holstenkamp; F Hüsing; N Langmaack; N Lemke; F Lippold; J Köhler; L Kühl; R Mallwitz; L Meyer; P Schönfeldt; W Tegethoff; J z Hingst; S Kabelac
Wärmepumpenforschung als Motor der Energiewende Vortrag
Berlin, Germany, 30.11.2021, (7. Dialogplattform Power-to-Heat).
@misc{Niepelt2021d,
title = {Wärmepumpenforschung als Motor der Energiewende},
author = {R Niepelt and B Engel and F Giovannetti and N Gräfer and M Henke and S Holler and L Holstenkamp and F Hüsing and N Langmaack and N Lemke and F Lippold and J Köhler and L Kühl and R Mallwitz and L Meyer and P Schönfeldt and W Tegethoff and J z Hingst and S Kabelac},
year = {2021},
date = {2021-11-30},
address = {Berlin, Germany},
note = {7. Dialogplattform Power-to-Heat},
keywords = {},
pubstate = {published},
tppubtype = {presentation}
}
16.
U Hansen-Röbbel; D Eggert
Warm ja, aber auch effizient? - Anlagenanalyse für den Handwerker Vortrag
Online Event, 25.11.2021, (Zukunftsfähige Gebäudeheizzentralen – Effiziente und CO2-minimierte Heizzentralen).
@misc{Hansen-Röbbel2021,
title = {Warm ja, aber auch effizient? - Anlagenanalyse für den Handwerker},
author = {U Hansen-Röbbel and D Eggert},
year = {2021},
date = {2021-11-25},
address = {Online Event},
note = {Zukunftsfähige Gebäudeheizzentralen – Effiziente und CO2-minimierte Heizzentralen},
keywords = {},
pubstate = {published},
tppubtype = {presentation}
}
17.
D Eggert
Verbundvorhaben FeBOp-MFH Vortrag
Online Event, 23.11.2021, (10. Projektleitungstreffen ENERGIEWENDEBAUEN „Gemeinsam auf dem Weg zur Klimaneutralität - Lösungen für eine zügige Transformation“).
@misc{Eggert2021,
title = {Verbundvorhaben FeBOp-MFH},
author = {D Eggert},
year = {2021},
date = {2021-11-23},
address = {Online Event},
note = {10. Projektleitungstreffen ENERGIEWENDEBAUEN „Gemeinsam auf dem Weg zur Klimaneutralität - Lösungen für eine zügige Transformation“},
keywords = {},
pubstate = {published},
tppubtype = {presentation}
}
18.
M Yasin
Permanente und automatisierte Betriebsanalyse von Wärmezentralen in Mehrfamilienhäusern Vortrag
Online Event, 16.11.2021, (Eversol Workshop „Regenerative Energieversorgung von Mehrfamilienhäusern – Umsetzung und Hürden“).
@misc{Yasin2021b,
title = {Permanente und automatisierte Betriebsanalyse von Wärmezentralen in Mehrfamilienhäusern},
author = {M Yasin},
year = {2021},
date = {2021-11-16},
address = {Online Event},
note = {Eversol Workshop „Regenerative Energieversorgung von Mehrfamilienhäusern – Umsetzung und Hürden“},
keywords = {},
pubstate = {published},
tppubtype = {presentation}
}
19.
J Govaerts; K Moliya; B Luo; T Borgers; R Van Dyck; A S H Heide; L Tous; A Morlier; F Lisco; L Cerasti; M Galiazzo; J Poortmans
The Potential of Glass-Fibre-Reinforcement: (Thermo-)Mechanical Testing of Light-Weight PV Modules Konferenzbeitrag
In: WIP, (Hrsg.): Proceedings of the 38th European Photovoltaic Solar Energy Conference and Exhibition, S. 24-27, Online Event, 2021, ISBN: 3-936338-78-7.
@inproceedings{Govaerts2021b,
title = {The Potential of Glass-Fibre-Reinforcement: (Thermo-)Mechanical Testing of Light-Weight PV Modules},
author = {J Govaerts and K Moliya and B Luo and T Borgers and R Van Dyck and A S H Heide and L Tous and A Morlier and F Lisco and L Cerasti and M Galiazzo and J Poortmans},
editor = {WIP},
doi = {10.4229/EUPVSEC20212021-1AO.3.1},
isbn = {3-936338-78-7},
year = {2021},
date = {2021-11-16},
booktitle = {Proceedings of the 38th European Photovoltaic Solar Energy Conference and Exhibition},
pages = {24-27},
address = {Online Event},
abstract = {In this work we report on our approach on integrating c-Si PV into lightweight structures, in particular towards vehicle integration. To this end we want to get rid of the (bulk weight of the) glass but seek a suitable replacement in terms of mechanical stability. First we elaborate on the most basic standards and norms that VIPV products should relate to in terms of (thermo-)mechanical testing. Then, for the experimental part, 2 concepts are investigated. In a first approach, we reinforced the encapsulant with glass fibre material, while in a second one we applied a dedicated glass-fibre-reinforced sheet as a replacement of the backsheet. In both cases we stay as close as possible to using commercially available material. Extending our previously reported work, we then elaborate for each approach the testing that has been carried out so far, and what is still ongoing and being planned in the short-term future (before the conference): indicating the promising results so far on thermal cycling and vibration testing, the hail impact testing is a challenge to be tackled still},
keywords = {},
pubstate = {published},
tppubtype = {inproceedings}
}
In this work we report on our approach on integrating c-Si PV into lightweight structures, in particular towards vehicle integration. To this end we want to get rid of the (bulk weight of the) glass but seek a suitable replacement in terms of mechanical stability. First we elaborate on the most basic standards and norms that VIPV products should relate to in terms of (thermo-)mechanical testing. Then, for the experimental part, 2 concepts are investigated. In a first approach, we reinforced the encapsulant with glass fibre material, while in a second one we applied a dedicated glass-fibre-reinforced sheet as a replacement of the backsheet. In both cases we stay as close as possible to using commercially available material. Extending our previously reported work, we then elaborate for each approach the testing that has been carried out so far, and what is still ongoing and being planned in the short-term future (before the conference): indicating the promising results so far on thermal cycling and vibration testing, the hail impact testing is a challenge to be tackled still
20.
S Wendlandt; S Heller; J Govaerts; A S H Heide; J Kaakkunen; T Savisalo; A Morlier; D Raine; D Röder
Angle of Incidence Study at Photovoltaic Modules with Polymer Front Sheet Konferenzbeitrag
In: WIP, (Hrsg.): Proceedings of the 38th European Photovoltaic Solar Energy Conference and Exhibition, S. 814-819, Online Event, 2021, ISBN: 3-936338-78-7.
@inproceedings{Wendlandt2021b,
title = {Angle of Incidence Study at Photovoltaic Modules with Polymer Front Sheet},
author = {S Wendlandt and S Heller and J Govaerts and A S H Heide and J Kaakkunen and T Savisalo and A Morlier and D Raine and D Röder},
editor = {WIP},
doi = {10.4229/EUPVSEC20212021-4AV.2.13},
isbn = {3-936338-78-7},
year = {2021},
date = {2021-11-16},
booktitle = {Proceedings of the 38th European Photovoltaic Solar Energy Conference and Exhibition},
pages = {814-819},
address = {Online Event},
abstract = {For years, photovoltaic systems have been successfully installed on a large scale on open spaces as well as on (BAPV) and on buildings (BIPV). For the applications, PV modules in the classic glass-backsheet or glass-glass design are mostly used because their properties are well known. For BIPV and further on for automotive applications (VIPV) it makes sense to reduce the weight of the modules in order not to overload the building’s loadbearing capacity statics as well as for vehicles to minimize their energy consumption. One approach for weight reduction is by replacing glass with polymer materials. The light coupling on typical PV modules is largely optimized by means of an anti-reflective coating (ARC) on the front glass. This has not yet been done for polymer front sheets, but this paper will take the first step and characterize different lightweight approaches based on polymer front sheets with different solar cell types (SHJ, IBC) for their skewing behavior and then give an evaluation of the electrical yield for angle-dependent installation as well as for different locations.},
keywords = {},
pubstate = {published},
tppubtype = {inproceedings}
}
For years, photovoltaic systems have been successfully installed on a large scale on open spaces as well as on (BAPV) and on buildings (BIPV). For the applications, PV modules in the classic glass-backsheet or glass-glass design are mostly used because their properties are well known. For BIPV and further on for automotive applications (VIPV) it makes sense to reduce the weight of the modules in order not to overload the building’s loadbearing capacity statics as well as for vehicles to minimize their energy consumption. One approach for weight reduction is by replacing glass with polymer materials. The light coupling on typical PV modules is largely optimized by means of an anti-reflective coating (ARC) on the front glass. This has not yet been done for polymer front sheets, but this paper will take the first step and characterize different lightweight approaches based on polymer front sheets with different solar cell types (SHJ, IBC) for their skewing behavior and then give an evaluation of the electrical yield for angle-dependent installation as well as for different locations.