Dr. Fraas has been active in the development of Solar Cells and Solar Electric Power Systems for space and terrestrial applications since 1975. In 1978, he published a pioneering paper proposing the InGaP/GaInAs/Ge triple junction solar cell predicting a cell terrestrial conversion efficiency of 40% at 300 suns concentration. He then led the research team at Boeing that demonstrated the first over 30% GaAs/GaSb tandem concentrator solar cell in 1989. He joined JX Crystals in 1993, where he has pioneered the development of various thermophotovoltaic (TPV) systems based on the GaSb infrared PV cell. Dr Fraas holds degrees from Caltech, Harvard, and USC. He has written over 350 technical papers, over 60 patents, and two books. His most recent book is a Springer 2014 book entitled Low Cost Solar Electric Power.
Zinc diffused P on N GaSb cells are typically used in TPV systems. However, there are three poten... more Zinc diffused P on N GaSb cells are typically used in TPV systems. However, there are three potential advantages for developing N on P GaSb cells. First, because the minority electron carrier diffusion length in the P type wafer is longer than the hole minority carrier diffusion length in N type wafers, the quantum efficiency near the GaSb band edge will be higher for N on P cells. This is important for TPV systems and demonstrated herein in the first fabricated diffused junction N on P cells. A second potential advantage could be a much simpler fabrication process if a transparent conductive oxide (TCO) N+ layer is used instead. A third advantage could be a built in long wavelength reflecting filter associated with the TCO which would be an efficiency advantage for a TPV system. The development of N on P GaSb cells is described herein.
A lot of coal is burned in the fabrication of steel. Steel is melted at a very high temperature a... more A lot of coal is burned in the fabrication of steel. Steel is melted at a very high temperature and steel billets glow white hot. Modified infrared sensitive solar modules can be mounted adjacent to the glowing steel billets to recover the wasted radiant energy and generate electricity. Herein, we propose to fabricate the world’s first infrared converter modules for the steel industry. We plan to install infrared converter modules at a Steel mill. This application has two cost advantages over solar. The first is the high power density, a factor of 100 over solar modules. The second distinct advantage over solar is the 24 hours of operation vs. just 8 hours / day for solar. The CO2 emissions per unit of electricity are estimated to be approximately 1 kg/kWh for a coal fired power plant. This means that a 1 GW coal fired electric power plant generates approximately 1000 metric tons of CO2 every hour. This means that if the waste heat from steel production worldwide were used to generate 10 GW of electricity, the CO2 emission rate could be reduced by 10,000 MT every hour or by 90 million MT per year. This effect would be worldwide but primarily in China and India.
Solar cells have now entered the main stream for electric power production. By the end of 2015, w... more Solar cells have now entered the main stream for electric power production. By the end of 2015, world wide cumulative solar cell electric power installed capacity will exceed 200 GW. This has surprised the main stream energy community. This has been accomplished mainly by using silicon module technology with cell efficiencies of approximately 15%. There are now more opportunities and challenges with exciting potential solutions. One of the challenges that solar energy faces is associated with the fact that solar energy is limited to daytime hours. A Space Power Satellite capable of providing solar electric power economically for 24 hours per day has been a dream for decades. Herein, an alternative will be described. A 10 km diameter constellation of mirror satellites in a sun synchronous orbit at an altitude of 1000 km deflecting sunbeams down to terrestrial solar power fields at dawn and dusk can provide 3 additional hours in the morning and another 3 additional hours in the evening. The key is that larger and larger terrestrial solar fields, photovoltaic or trough concentrated solar power, are already being built all around the world. Mirrors deflecting sunbeams down to earth is a much simpler concept. A surprising convergence of two technologies under development is now possible, i.e. lower cost access to space and the ongoing construction of larger and larger solar power fields. Further analysis of mirrors in space in a dawn dusk orbit combined with future solar power fields has shown this idea to be actually a potentially viable economical proposition [1, 2]. However, while this idea is very intriguing, the magnitude of its implementation is daunting. Nevertheless, the idea is intriguing enough to proceed with a first order design for the required mirror satellites. A mirror satellite development road-map will be presented here. It builds from mirror technology for solar sails as well as technology developed for the International Space Station. It appears that the technology is available to implement this mirror satellite design and at least go to a detailed design and test stage. If this concept is implemented in the future, the hours of solar electricity production in sunny PV fields around the world can be potentially increased to 14 hours per day with an increase in solar field capacity factor to 58% and a reduction in the cost of renewable pollution free solar electricity to below 6 cents per kWh. A first step in a development road-map could be the construction of a 20 m diameter space mirror to demonstrate full moon intensity illumination in Disney Parks in the evenings. [1] L. Fraas, “Mirrors in Space for Low Cost Terrestrial Solar Electric Power at Night", 38th IEEE PVSC, (June 3-8 2012). [2] L. Fraas, A. Palisoc, B. Derbes, “Mirrors in Dawn Dusk Orbit for Low Cost Solar Electric Power in the Evening", AIAA ASM Technical Conference, January 10. 2013.
Light Weight Fuel-Fired TPV Battery Replacement L Fraas1, J Avery1, L Minkin1, H She1, L Ferguson... more Light Weight Fuel-Fired TPV Battery Replacement L Fraas1, J Avery1, L Minkin1, H She1, L Ferguson2 1 JX Crystals Inc, Issaquah, WA, USA 2 C12 Advanced Technologies LLC, Everett, WA, USA PVSEC-26 Singapore Oct 2016 Both solar cells and batteries generate quiet DC electric power and solar cells are light weight but conventional solar cells only operate when the sun is shining. However, JX Crystals Inc (JXC) has invented and fabricates infrared (IR) sensitive solar cells that can convert energy from a combustion heated glowing ceramic IR emitter into electricity. The result is a lightweight thermophotovoltaic (TPV) battery replacement that operates day and night. We present here the design and operation of a first stand alone TPV generator complete with a photovoltaic converter array and a burner / emitter recuperator assembly and support components. The package dimensions are: L = 300 mm (12”), H = 131 mm (5.2”), W = 96 mm (3.8”). Its target performance is 25 W with a fuel burn rate of 500 W for an efficiency of 5%. This unit is designed to operate with 465g propane or propane/butane fuel cylinders.
It is well known that solar energy can be converted into heat or electrical energy and that these... more It is well known that solar energy can be converted into heat or electrical energy and that these forms have value. It is also well known that the sun’s light energy can be used directly for illumination. However, the economic value of sunlight is not generally appreciated.
While monolithic multi-junction cells are preferred for flat plate arrays, mechanically stacked m... more While monolithic multi-junction cells are preferred for flat plate arrays, mechanically stacked multi-junction cells are superior for solar concentrator applications. Reasons for this are that the mechanical stacked configuration with high efficiency Gallium Antimonide ...
Both solar cells and batteries generate quiet DC electric power. Infrared (IR) sensitive GaSb pho... more Both solar cells and batteries generate quiet DC electric power. Infrared (IR) sensitive GaSb photovoltaic cells can convert energy from a combustion heated glowing ceramic IR emitter into electricity. The result is a lightweight thermophotovoltaic (TPV) battery replacement that operates day and night. We present here the design and operation of a first stand alone TPV generator. Test results on this unit have allowed us to design a scale-up hand-held 10% efficient 50 W TPV generator weighing 1.5 kg. The 50 W scale-up TPV power supply along with 1.5 kg of fuel has a projected weight specific energy density of 645 Wh/kg. This is 4 times larger than for a Li ion battery.
Gallium Antimonide (GaSb) infrared photovoltaic cells are light weight whereas batteries are heav... more Gallium Antimonide (GaSb) infrared photovoltaic cells are light weight whereas batteries are heavy. The specific energy in a hydrocarbon fuel is high at 12,900 W-hr per kg but a lithium ion rechargeable battery has a specific energy of only 145 W-hr per kg. A 10% efficient portable lightweight thermophotovoltaic (TPV) cylindrical generator when compared with a battery can have 6.5 times higher specific energy, operates 7 times longer, and be quickly refueled. The key is the 10% efficiency goal. This efficiency goal depends on matching the spectrum from a combustion heated ceramic IR emitter to the response band of the IR PV cell. Herein, spectral measurements are presented for a propane burner and ceramic IR emitter assembly surrounded by a fused silica glass envelope. The cylindrical IR ceramic emitter consists of an array of NiO doped MgO rods or slats. The Ni ion emission line is centered at 1.6 microns and it matches the GaSb IR response band extending out to 1.8 microns. The ceramic IR emitter is combustion heated to approximately 1200 C. The fuel and air combustion efficiency and hot gas coupling efficiency to the IR emitter are also important parameters.
2018 IEEE 7th World Conference on Photovoltaic Energy Conversion (WCPEC) (A Joint Conference of 45th IEEE PVSC, 28th PVSEC & 34th EU PVSEC), 2018
An optimized design of a Heterojunction N+ on P GaSb thermophotovoltaic (TPV) cell with hydrogena... more An optimized design of a Heterojunction N+ on P GaSb thermophotovoltaic (TPV) cell with hydrogenated amorphous silicon interface passivation is presented. The N+ layer is a transparent conductive oxide (TCO). The interface recombination rate between the p-GaSb and a-Si:H(i) layers is found to have an important effect on cell performance. If this recombination rate can be reduced to 105cm/s, the internal quantum efficiency in the wave range of 600 1700 nm surpasses 95% and the output power density reaches 2W/cm2 under a given blackbody radiation of 1500K. The high minority carrier electron mobility and diffusion length in the p-GaSb leads to the high internal quantum efficiency. A potential advantage of this cell is its simple cell fabrication process for low cost in high volume manufacturing. Another advantage for this cell for TPV systems is a built in short pass plasma filter with a high reflectivity at longer wavelengths.
It has been previously noted that GaSb infrared-sensitive cells can be stacked behind transparent... more It has been previously noted that GaSb infrared-sensitive cells can be stacked behind transparent GaAs cells to boost solar cell energy conversion efficiencies to well over 30% for space and terrestrial applications. Verified spectral response and current versus voltage data for both GaAs and GaSb cells along with Sandia National Laboratories clear-day solar spectral data for Albuquerque, US, are used
A Space Power Satellite capable of providing solar electric power economically for 24 hours per d... more A Space Power Satellite capable of providing solar electric power economically for 24 hours per day has been a dream for decades. Herein, an alternative will be described. Mirrors deflecting sunbeams down to earth is a much simpler concept. While this idea is very intriguing, the magnitude of its implementation is daunting. Nevertheless, the idea is intriguing enough to proceed with a first order design for the required space mirror satellites. A first step in a development road-map could be the construction of a 12 square meter space mirror to demonstrate full moon intensity illumination in Disney Parks in the evenings. This first small space mirror could potentially be deployed on the International Space Station for testing and proof of concept experiments.
Extrapolations of `Swanson's Law' (a learning curve) and its replot project that solar ce... more Extrapolations of `Swanson's Law' (a learning curve) and its replot project that solar cells (predominately crystalline Si so far) can match the world's current power generating capacity at lower costs than fossil fuels and with a net gain in jobs - all by 2032. Existing wind and solar cell resources are sufficient for this transition. If wind and solar variability can be accommodated, greenhouse gas emissions (from burning fossil fuels) can be eliminated 18 years earlier than others propose. This is probably necessary to avoid disastrous climate change, which is likely irreversible over a 1000's-of-years-time-frame, if all fossil fuels are burned.
Zinc diffused P on N GaSb cells are typically used in TPV systems. However, there are three poten... more Zinc diffused P on N GaSb cells are typically used in TPV systems. However, there are three potential advantages for developing N on P GaSb cells. First, because the minority electron carrier diffusion length in the P type wafer is longer than the hole minority carrier diffusion length in N type wafers, the quantum efficiency near the GaSb band edge will be higher for N on P cells. This is important for TPV systems and demonstrated herein in the first fabricated diffused junction N on P cells. A second potential advantage could be a much simpler fabrication process if a transparent conductive oxide (TCO) N+ layer is used instead. A third advantage could be a built in long wavelength reflecting filter associated with the TCO which would be an efficiency advantage for a TPV system. The development of N on P GaSb cells is described herein.
A lot of coal is burned in the fabrication of steel. Steel is melted at a very high temperature a... more A lot of coal is burned in the fabrication of steel. Steel is melted at a very high temperature and steel billets glow white hot. Modified infrared sensitive solar modules can be mounted adjacent to the glowing steel billets to recover the wasted radiant energy and generate electricity. Herein, we propose to fabricate the world’s first infrared converter modules for the steel industry. We plan to install infrared converter modules at a Steel mill. This application has two cost advantages over solar. The first is the high power density, a factor of 100 over solar modules. The second distinct advantage over solar is the 24 hours of operation vs. just 8 hours / day for solar. The CO2 emissions per unit of electricity are estimated to be approximately 1 kg/kWh for a coal fired power plant. This means that a 1 GW coal fired electric power plant generates approximately 1000 metric tons of CO2 every hour. This means that if the waste heat from steel production worldwide were used to generate 10 GW of electricity, the CO2 emission rate could be reduced by 10,000 MT every hour or by 90 million MT per year. This effect would be worldwide but primarily in China and India.
Solar cells have now entered the main stream for electric power production. By the end of 2015, w... more Solar cells have now entered the main stream for electric power production. By the end of 2015, world wide cumulative solar cell electric power installed capacity will exceed 200 GW. This has surprised the main stream energy community. This has been accomplished mainly by using silicon module technology with cell efficiencies of approximately 15%. There are now more opportunities and challenges with exciting potential solutions. One of the challenges that solar energy faces is associated with the fact that solar energy is limited to daytime hours. A Space Power Satellite capable of providing solar electric power economically for 24 hours per day has been a dream for decades. Herein, an alternative will be described. A 10 km diameter constellation of mirror satellites in a sun synchronous orbit at an altitude of 1000 km deflecting sunbeams down to terrestrial solar power fields at dawn and dusk can provide 3 additional hours in the morning and another 3 additional hours in the evening. The key is that larger and larger terrestrial solar fields, photovoltaic or trough concentrated solar power, are already being built all around the world. Mirrors deflecting sunbeams down to earth is a much simpler concept. A surprising convergence of two technologies under development is now possible, i.e. lower cost access to space and the ongoing construction of larger and larger solar power fields. Further analysis of mirrors in space in a dawn dusk orbit combined with future solar power fields has shown this idea to be actually a potentially viable economical proposition [1, 2]. However, while this idea is very intriguing, the magnitude of its implementation is daunting. Nevertheless, the idea is intriguing enough to proceed with a first order design for the required mirror satellites. A mirror satellite development road-map will be presented here. It builds from mirror technology for solar sails as well as technology developed for the International Space Station. It appears that the technology is available to implement this mirror satellite design and at least go to a detailed design and test stage. If this concept is implemented in the future, the hours of solar electricity production in sunny PV fields around the world can be potentially increased to 14 hours per day with an increase in solar field capacity factor to 58% and a reduction in the cost of renewable pollution free solar electricity to below 6 cents per kWh. A first step in a development road-map could be the construction of a 20 m diameter space mirror to demonstrate full moon intensity illumination in Disney Parks in the evenings. [1] L. Fraas, “Mirrors in Space for Low Cost Terrestrial Solar Electric Power at Night", 38th IEEE PVSC, (June 3-8 2012). [2] L. Fraas, A. Palisoc, B. Derbes, “Mirrors in Dawn Dusk Orbit for Low Cost Solar Electric Power in the Evening", AIAA ASM Technical Conference, January 10. 2013.
Light Weight Fuel-Fired TPV Battery Replacement L Fraas1, J Avery1, L Minkin1, H She1, L Ferguson... more Light Weight Fuel-Fired TPV Battery Replacement L Fraas1, J Avery1, L Minkin1, H She1, L Ferguson2 1 JX Crystals Inc, Issaquah, WA, USA 2 C12 Advanced Technologies LLC, Everett, WA, USA PVSEC-26 Singapore Oct 2016 Both solar cells and batteries generate quiet DC electric power and solar cells are light weight but conventional solar cells only operate when the sun is shining. However, JX Crystals Inc (JXC) has invented and fabricates infrared (IR) sensitive solar cells that can convert energy from a combustion heated glowing ceramic IR emitter into electricity. The result is a lightweight thermophotovoltaic (TPV) battery replacement that operates day and night. We present here the design and operation of a first stand alone TPV generator complete with a photovoltaic converter array and a burner / emitter recuperator assembly and support components. The package dimensions are: L = 300 mm (12”), H = 131 mm (5.2”), W = 96 mm (3.8”). Its target performance is 25 W with a fuel burn rate of 500 W for an efficiency of 5%. This unit is designed to operate with 465g propane or propane/butane fuel cylinders.
It is well known that solar energy can be converted into heat or electrical energy and that these... more It is well known that solar energy can be converted into heat or electrical energy and that these forms have value. It is also well known that the sun’s light energy can be used directly for illumination. However, the economic value of sunlight is not generally appreciated.
While monolithic multi-junction cells are preferred for flat plate arrays, mechanically stacked m... more While monolithic multi-junction cells are preferred for flat plate arrays, mechanically stacked multi-junction cells are superior for solar concentrator applications. Reasons for this are that the mechanical stacked configuration with high efficiency Gallium Antimonide ...
Both solar cells and batteries generate quiet DC electric power. Infrared (IR) sensitive GaSb pho... more Both solar cells and batteries generate quiet DC electric power. Infrared (IR) sensitive GaSb photovoltaic cells can convert energy from a combustion heated glowing ceramic IR emitter into electricity. The result is a lightweight thermophotovoltaic (TPV) battery replacement that operates day and night. We present here the design and operation of a first stand alone TPV generator. Test results on this unit have allowed us to design a scale-up hand-held 10% efficient 50 W TPV generator weighing 1.5 kg. The 50 W scale-up TPV power supply along with 1.5 kg of fuel has a projected weight specific energy density of 645 Wh/kg. This is 4 times larger than for a Li ion battery.
Gallium Antimonide (GaSb) infrared photovoltaic cells are light weight whereas batteries are heav... more Gallium Antimonide (GaSb) infrared photovoltaic cells are light weight whereas batteries are heavy. The specific energy in a hydrocarbon fuel is high at 12,900 W-hr per kg but a lithium ion rechargeable battery has a specific energy of only 145 W-hr per kg. A 10% efficient portable lightweight thermophotovoltaic (TPV) cylindrical generator when compared with a battery can have 6.5 times higher specific energy, operates 7 times longer, and be quickly refueled. The key is the 10% efficiency goal. This efficiency goal depends on matching the spectrum from a combustion heated ceramic IR emitter to the response band of the IR PV cell. Herein, spectral measurements are presented for a propane burner and ceramic IR emitter assembly surrounded by a fused silica glass envelope. The cylindrical IR ceramic emitter consists of an array of NiO doped MgO rods or slats. The Ni ion emission line is centered at 1.6 microns and it matches the GaSb IR response band extending out to 1.8 microns. The ceramic IR emitter is combustion heated to approximately 1200 C. The fuel and air combustion efficiency and hot gas coupling efficiency to the IR emitter are also important parameters.
2018 IEEE 7th World Conference on Photovoltaic Energy Conversion (WCPEC) (A Joint Conference of 45th IEEE PVSC, 28th PVSEC & 34th EU PVSEC), 2018
An optimized design of a Heterojunction N+ on P GaSb thermophotovoltaic (TPV) cell with hydrogena... more An optimized design of a Heterojunction N+ on P GaSb thermophotovoltaic (TPV) cell with hydrogenated amorphous silicon interface passivation is presented. The N+ layer is a transparent conductive oxide (TCO). The interface recombination rate between the p-GaSb and a-Si:H(i) layers is found to have an important effect on cell performance. If this recombination rate can be reduced to 105cm/s, the internal quantum efficiency in the wave range of 600 1700 nm surpasses 95% and the output power density reaches 2W/cm2 under a given blackbody radiation of 1500K. The high minority carrier electron mobility and diffusion length in the p-GaSb leads to the high internal quantum efficiency. A potential advantage of this cell is its simple cell fabrication process for low cost in high volume manufacturing. Another advantage for this cell for TPV systems is a built in short pass plasma filter with a high reflectivity at longer wavelengths.
It has been previously noted that GaSb infrared-sensitive cells can be stacked behind transparent... more It has been previously noted that GaSb infrared-sensitive cells can be stacked behind transparent GaAs cells to boost solar cell energy conversion efficiencies to well over 30% for space and terrestrial applications. Verified spectral response and current versus voltage data for both GaAs and GaSb cells along with Sandia National Laboratories clear-day solar spectral data for Albuquerque, US, are used
A Space Power Satellite capable of providing solar electric power economically for 24 hours per d... more A Space Power Satellite capable of providing solar electric power economically for 24 hours per day has been a dream for decades. Herein, an alternative will be described. Mirrors deflecting sunbeams down to earth is a much simpler concept. While this idea is very intriguing, the magnitude of its implementation is daunting. Nevertheless, the idea is intriguing enough to proceed with a first order design for the required space mirror satellites. A first step in a development road-map could be the construction of a 12 square meter space mirror to demonstrate full moon intensity illumination in Disney Parks in the evenings. This first small space mirror could potentially be deployed on the International Space Station for testing and proof of concept experiments.
Extrapolations of `Swanson's Law' (a learning curve) and its replot project that solar ce... more Extrapolations of `Swanson's Law' (a learning curve) and its replot project that solar cells (predominately crystalline Si so far) can match the world's current power generating capacity at lower costs than fossil fuels and with a net gain in jobs - all by 2032. Existing wind and solar cell resources are sufficient for this transition. If wind and solar variability can be accommodated, greenhouse gas emissions (from burning fossil fuels) can be eliminated 18 years earlier than others propose. This is probably necessary to avoid disastrous climate change, which is likely irreversible over a 1000's-of-years-time-frame, if all fossil fuels are burned.
— A Space Power Satellite capable of providing solar electric power economically for 24 hours per... more — A Space Power Satellite capable of providing solar electric power economically for 24 hours per day has been a dream for decades. Herein, an alternative will be described. Mirrors deflecting sunbeams down to earth is a much simpler concept. While this idea is very intriguing, the magnitude of its implementation is daunting. Nevertheless, the idea is intriguing enough to proceed with a first order design for the required space mirror satellites. A first step in a development road-map could be the construction of a 12 square meter space mirror to demonstrate full moon intensity illumination in Disney Parks in the evenings. This first small space mirror could potentially be deployed on the International Space Station for testing and proof of concept experiments.
— Gallium Antimonide (GaSb) infrared photovoltaic cells are light weight whereas batteries are he... more — Gallium Antimonide (GaSb) infrared photovoltaic cells are light weight whereas batteries are heavy. The specific energy in a hydrocarbon fuel is high at 12,900 W-hr per kg but a lithium ion rechargeable battery has a specific energy of only 145 W-hr per kg. A 10% efficient portable lightweight thermophotovoltaic (TPV) cylindrical generator when compared with a battery can have 6.5 times higher specific energy, operates 7 times longer, and be quickly refueled. The key is the 10% efficiency goal. This efficiency goal depends on matching the spectrum from a combustion heated ceramic IR emitter to the response band of the IR PV cell. Herein, spectral measurements are presented for a propane burner and ceramic IR emitter assembly surrounded by a fused silica glass envelope. The cylindrical IR ceramic emitter consists of NiO doped MgO rods or slats. The Ni ion emission line is centered at 1.6 microns and it matches the GaSb IR response band extending out to 1.8 microns. The ceramic IR emitter is combustion heated to approximately 1200 C.
— An optimized design of a Heterojunction N+ on P GaSb thermophotovoltaic (TPV) cell with hydroge... more — An optimized design of a Heterojunction N+ on P GaSb thermophotovoltaic (TPV) cell with hydrogenated amorphous silicon interface passivation is presented. The N+ layer is a transparent conductive oxide (TCO). The interface recombination rate between the p-GaSb and a-Si:H(i) layers is found to have an important effect on cell performance. If this recombination rate can be reduced to 10 5 cm/s, the internal quantum efficiency in the wave range of 600~1700 nm surpasses 95% and the output power density reaches 2W/cm 2 under a given blackbody radiation of 1500K. The high minority carrier electron mobility and diffusion length in the p-GaSb leads to the high internal quantum efficiency. A potential advantage of this cell is its simple cell fabrication process for low cost in high volume manufacturing. Another advantage for this cell for TPV systems is a built in short pass plasma filter with a high reflectivity at longer wavelengths.
Thermophotovoltaics (TPV) is complimentary to Solar Photovoltaics but it operates at night and in... more Thermophotovoltaics (TPV) is complimentary to Solar Photovoltaics but it operates at night and in cold climates TPV is ideal for small and large scale Combined Heat & Power and it uses natural gas TPV is lightweight and can be used as a battery replacement or in UAVs TPV can be used in steel mills to convert waste heat into electricity 24 hrs per day 7 days a week and this is a huge market JX Crystals IR cells in quantity are key to a large number of new applications
GaSb Cells and IR Power Beaming
Lewis M. Fraas & Han Xiang Huang
JX Crystals Inc, Issaquah, WA
... more GaSb Cells and IR Power Beaming
Lewis M. Fraas & Han Xiang Huang JX Crystals Inc, Issaquah, WA
TPV-8, Palm Desert, CA November 2008
IR Power Beaming is an application where the system development is straight forward. Eye-safe IR lasers are already available. GaSb PV cells are ideal for low cost IR power conversion at power densities as high as 10 W/cm2 and at costs as low as 50 cents per W. However, cost is controlled by production volume with high volume required (>5000 wafers per year). Material costs are not important until production volumes approach 10 MW per year.
Light Weight Fuel-Fired TPV Battery Replacement
L Fraas1, J Avery1, L Minkin1, H She1, L Ferguso... more Light Weight Fuel-Fired TPV Battery Replacement
L Fraas1, J Avery1, L Minkin1, H She1, L Ferguson2 1 JX Crystals Inc, Issaquah, WA, USA 2 C12 Advanced Technologies LLC, Everett, WA, USA
PVSEC-26 Singapore Oct 2016
Both solar cells and batteries generate quiet DC electric power and solar cells are light weight but conventional solar cells only operate when the sun is shining. However, JX Crystals Inc (JXC) has invented and fabricates infrared (IR) sensitive solar cells that can convert energy from a combustion heated glowing ceramic IR emitter into electricity. The result is a lightweight thermophotovoltaic (TPV) battery replacement that operates day and night. We present here the design and operation of a first stand alone TPV generator complete with a photovoltaic converter array and a burner / emitter recuperator assembly and support components. The package dimensions are: L = 300 mm (12”), H = 131 mm (5.2”), W = 96 mm (3.8”). Its target performance is 25 W with a fuel burn rate of 500 W for an efficiency of 5%. This unit is designed to operate with 465g propane or propane/butane fuel cylinders.
Lightweight mirrors have been proposed in geosynchronous orbit for the generation of Space Solar ... more Lightweight mirrors have been proposed in geosynchronous orbit for the generation of Space Solar Power 24 hours per day [1]. Alternatively, lightweight space mirrors have been proposed in sun-synchronous polar orbits for illuminating terrestrial solar fields at dawn and dusk for additional terrestrial solar electric power in the early morning and evening hours [2]. In any case, the trade offs between lightweight, stiffness, and optical quality for low cost space mirrors need to be explored. These trade-offs can be explored by developing and demonstrating a lightweight mirror on the International Space Station. The astronauts on the ISS will see dawn and dusk 15 times per day. Herein, it is noted that a first step in a space mirror development road-map could be the construction of a 12 square meter space mirror to demonstrate full moon intensity illumination in Disney Parks in the evenings. The 400 km altitude of the ISS is an advantage in that a small 12 sq m mirror can produce full-moon intensity on a 4 km diameter spot on the ground provided that the mirror is flat to within 0.5 degrees, i.e. the sun disc size. There are multiple websites to allow one to locate the ISS in the evening [3] demonstrating that the ISS is visible for up to 6 minutes routinely in the evenings at any ground location between +/- 52 degrees latitude. Demonstrating a flat pointing moonbeam space mirror on the ISS would be a significant accomplishment. A challenge for engineering students could be to design, build and ground test a 12 sq m space mirror prototype. [1] J. Mankins, The Case for Space Solar Power, Virginia Edition Publishing; First Edition (January 5, 2014), Amazon Digital Services, ASIN: B00HNZ0Z96 [2] L. Fraas, Low Cost Solar Electric Power Chapter 12, Springer (2014). [3] ISS sightings over your city | Spot The Station | NASA
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Papers by Lewis Fraas
TPV is ideal for small and large scale Combined Heat & Power and it uses natural gas
TPV is lightweight and can be used as a battery replacement or in UAVs
TPV can be used in steel mills to convert waste heat into electricity 24 hrs per day 7 days a week and this is a huge market
JX Crystals IR cells in quantity are key to a large number of new applications
Lewis M. Fraas & Han Xiang Huang
JX Crystals Inc, Issaquah, WA
TPV-8, Palm Desert, CA
November 2008
IR Power Beaming is an application where the system development is straight forward. Eye-safe IR lasers are already available. GaSb PV cells are ideal for low cost IR power conversion at power densities as high as 10 W/cm2 and at costs as low as 50 cents per W. However, cost is controlled by production volume with high volume required (>5000 wafers per year). Material costs are not important until production volumes approach 10 MW per year.
L Fraas1, J Avery1, L Minkin1, H She1, L Ferguson2
1 JX Crystals Inc, Issaquah, WA, USA
2 C12 Advanced Technologies LLC, Everett, WA, USA
PVSEC-26 Singapore Oct 2016
Both solar cells and batteries generate quiet DC electric power and solar cells are light weight but conventional solar cells only operate when the sun is shining. However, JX Crystals Inc (JXC) has invented and fabricates infrared (IR) sensitive solar cells that can convert energy from a combustion heated glowing ceramic IR emitter into electricity. The result is a lightweight thermophotovoltaic (TPV) battery replacement that operates day and night.
We present here the design and operation of a first stand alone TPV generator complete with a photovoltaic converter array and a burner / emitter recuperator assembly and support components. The package dimensions are: L = 300 mm (12”), H = 131 mm (5.2”), W = 96 mm (3.8”). Its target performance is 25 W with a fuel burn rate of 500 W for an efficiency of 5%. This unit is designed to operate with 465g propane or propane/butane fuel cylinders.
[1] J. Mankins, The Case for Space Solar Power, Virginia Edition Publishing; First Edition (January 5, 2014), Amazon Digital Services, ASIN: B00HNZ0Z96
[2] L. Fraas, Low Cost Solar Electric Power Chapter 12, Springer (2014).
[3] ISS sightings over your city | Spot The Station | NASA