A detailed Simulink simulation of a mechanical ventilator including a realistic model of a breath... more A detailed Simulink simulation of a mechanical ventilator including a realistic model of a breathing patient
Renewable fuel generation is essential for a low carbon footprint economy. Thus, over the last fi... more Renewable fuel generation is essential for a low carbon footprint economy. Thus, over the last five decades, a significant effort has been dedicated towards increasing the performance of solar fuels generating devices. Specifically, the solar to hydrogen efficiency of photoelectrochemical cells has progressed steadily towards its fundamental limit, and the faradaic efficiency towards valuable products in CO2 reduction systems has increased dramatically. However, there are still numerous scientific and engineering challenges that must be overcame in order to turn solar fuels into a viable technology. At the electrode and device level, the conversion efficiency, stability and products selectivity must be increased significantly. Meanwhile, these performance metrics must be maintained when scaling up devices and systems while maintaining an acceptable cost and carbon footprint. This roadmap surveys different aspects of this endeavor: system benchmarking, device scaling, various approaches for photoelectrodes design, materials discovery, and catalysis. Each of the sections in the roadmap focuses on a single topic, discussing the state of the art, the key challenges and advancements required to meet them. The roadmap can be used as a guide for researchers and funding agencies highlighting the most pressing needs of the field.
High concentration PV systems usually prefer tandem III-V cells to Si cells, due to the much lowe... more High concentration PV systems usually prefer tandem III-V cells to Si cells, due to the much lower conversion efficiency of the latter. We re-examine the efficiency achievable with Si Vertical Multi-Junction (VMJ) cells consisting of series-connected vertical p-n junctions within a single cell. A comprehensive 2D numerical analysis of a Si vertical junction has been performed, over a wide range of design parameters and concentration levels. The results show outstanding performance potential under high concentration of 1,000 suns and higher, with efficiencies above 29% under realistic (non-ideal) assumptions. This compares to reported efficiencies of about 20% for both real cells and previous simulations using realistic assumptions. This difference may be attributed to two effects: a better representation of the active layer photoconductivity, which lowers drastically the cell's series resistance under high concentration; and optimization of the junction dimensions without restriction due to the accepted fabrication process.
2012 IEEE 27th Convention of Electrical and Electronics Engineers in Israel, 2012
A new class of solar energy converters is described, based on photon-enhanced thermionic emission... more A new class of solar energy converters is described, based on photon-enhanced thermionic emission of electrons into a vacuum region between two electrodes. In contrast to conventional thermionic converters, the two electrodes are at the same temperature, and the cathode is side-illuminated rather than front-illuminated. This configuration leads to several advantages: close coupling of multiple units in a series connection high-voltage configuration; higher area for electron emission; and recovery of waste heat at a higher temperature compared to heat recovery from the anode of a conventional thermionic converter. The conversion efficiency from solar radiation to electricity of the new photo-thermionic device may be in the range of 30-40% at moderate operation temperatures and moderate concentration of the incident sunlight.
2012 IEEE 27th Convention of Electrical and Electronics Engineers in Israel, 2012
A new class of solar energy converters is described, based on photon-enhanced thermionic emission... more A new class of solar energy converters is described, based on photon-enhanced thermionic emission of electrons into a vacuum region between two electrodes. In contrast to conventional thermionic converters, the two electrodes are at the same temperature, and the cathode is side-illuminated rather than front-illuminated. This configuration leads to several advantages: close coupling of multiple units in a series connection high-voltage configuration; higher area for electron emission; and recovery of waste heat at a higher temperature compared to heat recovery from the anode of a conventional thermionic converter. The conversion efficiency from solar radiation to electricity of the new photo-thermionic device may be in the range of 30-40% at moderate operation temperatures and moderate concentration of the incident sunlight.
2010 IEEE 26-th Convention of Electrical and Electronics Engineers in Israel, 2010
Abstract High concentration PV systems usually prefer tandem III-V cells to Si cells, due to the ... more Abstract High concentration PV systems usually prefer tandem III-V cells to Si cells, due to the much lower conversion efficiency of the latter. We re-examine the efficiency achievable with Si Vertical Multi-Junction (VMJ) cells consisting of series-connected vertical pn ...
A detailed Simulink simulation of a mechanical ventilator including a realistic model of a breath... more A detailed Simulink simulation of a mechanical ventilator including a realistic model of a breathing patient
Renewable fuel generation is essential for a low carbon footprint economy. Thus, over the last fi... more Renewable fuel generation is essential for a low carbon footprint economy. Thus, over the last five decades, a significant effort has been dedicated towards increasing the performance of solar fuels generating devices. Specifically, the solar to hydrogen efficiency of photoelectrochemical cells has progressed steadily towards its fundamental limit, and the faradaic efficiency towards valuable products in CO2 reduction systems has increased dramatically. However, there are still numerous scientific and engineering challenges that must be overcame in order to turn solar fuels into a viable technology. At the electrode and device level, the conversion efficiency, stability and products selectivity must be increased significantly. Meanwhile, these performance metrics must be maintained when scaling up devices and systems while maintaining an acceptable cost and carbon footprint. This roadmap surveys different aspects of this endeavor: system benchmarking, device scaling, various approaches for photoelectrodes design, materials discovery, and catalysis. Each of the sections in the roadmap focuses on a single topic, discussing the state of the art, the key challenges and advancements required to meet them. The roadmap can be used as a guide for researchers and funding agencies highlighting the most pressing needs of the field.
High concentration PV systems usually prefer tandem III-V cells to Si cells, due to the much lowe... more High concentration PV systems usually prefer tandem III-V cells to Si cells, due to the much lower conversion efficiency of the latter. We re-examine the efficiency achievable with Si Vertical Multi-Junction (VMJ) cells consisting of series-connected vertical p-n junctions within a single cell. A comprehensive 2D numerical analysis of a Si vertical junction has been performed, over a wide range of design parameters and concentration levels. The results show outstanding performance potential under high concentration of 1,000 suns and higher, with efficiencies above 29% under realistic (non-ideal) assumptions. This compares to reported efficiencies of about 20% for both real cells and previous simulations using realistic assumptions. This difference may be attributed to two effects: a better representation of the active layer photoconductivity, which lowers drastically the cell's series resistance under high concentration; and optimization of the junction dimensions without restriction due to the accepted fabrication process.
2012 IEEE 27th Convention of Electrical and Electronics Engineers in Israel, 2012
A new class of solar energy converters is described, based on photon-enhanced thermionic emission... more A new class of solar energy converters is described, based on photon-enhanced thermionic emission of electrons into a vacuum region between two electrodes. In contrast to conventional thermionic converters, the two electrodes are at the same temperature, and the cathode is side-illuminated rather than front-illuminated. This configuration leads to several advantages: close coupling of multiple units in a series connection high-voltage configuration; higher area for electron emission; and recovery of waste heat at a higher temperature compared to heat recovery from the anode of a conventional thermionic converter. The conversion efficiency from solar radiation to electricity of the new photo-thermionic device may be in the range of 30-40% at moderate operation temperatures and moderate concentration of the incident sunlight.
2012 IEEE 27th Convention of Electrical and Electronics Engineers in Israel, 2012
A new class of solar energy converters is described, based on photon-enhanced thermionic emission... more A new class of solar energy converters is described, based on photon-enhanced thermionic emission of electrons into a vacuum region between two electrodes. In contrast to conventional thermionic converters, the two electrodes are at the same temperature, and the cathode is side-illuminated rather than front-illuminated. This configuration leads to several advantages: close coupling of multiple units in a series connection high-voltage configuration; higher area for electron emission; and recovery of waste heat at a higher temperature compared to heat recovery from the anode of a conventional thermionic converter. The conversion efficiency from solar radiation to electricity of the new photo-thermionic device may be in the range of 30-40% at moderate operation temperatures and moderate concentration of the incident sunlight.
2010 IEEE 26-th Convention of Electrical and Electronics Engineers in Israel, 2010
Abstract High concentration PV systems usually prefer tandem III-V cells to Si cells, due to the ... more Abstract High concentration PV systems usually prefer tandem III-V cells to Si cells, due to the much lower conversion efficiency of the latter. We re-examine the efficiency achievable with Si Vertical Multi-Junction (VMJ) cells consisting of series-connected vertical pn ...
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