Fraas L.M.,JX Crystals Inc.
Proceedings of the International Astronautical Congress, IAC
A Space Power Satellite capable of providing solar electric power economically for 24 hours per day has been a dream for decades. However, the SPS concept is very complex since it assumes multiple energy conversion steps and includes specially constructed ground microwave receiver stations. The 5 km by 15 km Integrated Symmetric Concentrator SPS concept employs light weight mirrors in a GEO orbit. Herein, it is proposed to use a constellation of 10 km diameter mirror arrays in a much lower sun synchronous orbit at an altitude of 1000 km deflecting sunbeams down to terrestrial solar power fields at dawn and dusk. 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 numerous larger solar power fields. The novelty here is the idea of a constellation of mirrors in a sun-synchronous dawn/dusk orbit in combination with future multiple 5-GW solar farms distributed around the world. In this scenario, the projected payback time for the mirror constellation given the additional revenues from the multiple solar fields is approximately 2 years. The key to the attractive economics for this concept is that the mirror constellation is used continuously over a 24 hour period by multiple terrestrial fields as each field comes into view at dawn or dusk. However, while this idea is very intriguing, the magnitude of its implementation is daunting. Nevertheless, the idea is intriguing enough to proceed with an initial design for the required mirror satellites. A mirror satellite design is 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. Given all of the above, there is still another non-technical difference between this dawn dusk space mirror concept and the initial SPS concept and that difference is in perspective. The dawn dusk space mirror concept requires a global perspective and international cooperation whereas the SPS concept is based on a traditional national perspective. In this regard, the International Space Station does provide hope for future international cooperation. Copyright © 2013 by the International Astronautical Federation. All rights reserved. Source
Fraas L.M.,JX Crystals Inc. |
Qiu K.,CANMET Energy
Materials Research Society Symposium Proceedings
A high temperature ceramic selective emitter for thermophotovoltaic (TPV) electric generators is described with a spectral match to GaSb IR cells. While solar cells generate electricity quietly and are lightweight, traditional solar cells are used with sunlight and only generate electricity during the day. Workers at JX Crystals invented the GaSb IR cell as a booster cell to demonstrate a solar cell conversion efficiency of 35%. JX Crystals now makes these IR cells. In TPV, these cells can potentially be used with flame heated ceramic emitters to generate electricity quietly day and night. One of the most important requirements for TPV is a good spectral match between the ceramic IR emitted and the IR PV cells. The first problem is to find, demonstrate, and integrate a doped ceramic IR emitter with a spectral match to these GaSb cells. Recently, nickel oxide and cobalt oxide doped MgO-based ceramics have been shown experimentally and theoretically to have spectral selectivity but no attempts have been made to integrate these ceramic IR emitters into a fully operational TPV generator. Herein, we review the history of TPV and note that a key to future progress will be the integration of an appropriate ceramic emitter with cells and a burner to demonstrate an operational TPV generator. Integrating TPV into a residential boiler is discussed as a potential future large volume commercial market. © 2013 Materials Research Society. Source
Partain L.,Solar Cell Electricity |
Fraas L.,JX Crystals Inc.
2015 IEEE 42nd Photovoltaic Specialist Conference, PVSC 2015
Unsubsidized costs of solar PV and wind energy are beginning to directly compete with coal and natural gas in some locations. The time is fast approaching when firm plans for their widespread adoption will be needed, once renewable energy variability is reconciled with daily utility electricity demand profiles. A recent four-year study of the PJM regional transmission district indicated that 99.9% grid reliability could be achieved if electric vehicle-to-grid energy storage were used in tandem with solar and wind generation. Applying this to estimate the number of grid-connected electric vehicles needed to displace the coal and nuclear power generation in California gives 1.7 million vehicles (just 8% of California's 22 million passenger vehicles), when combined with 12 GW of utility solar PV and wind generation capacity. This combination offers potential solutions to greenhouse-gas-emission-driven global climate change problems. © 2015 IEEE. Source
Fraas L.M.,JX Crystals Inc.
Conference Record of the IEEE Photovoltaic Specialists Conference
A constellation of 18 mirror satellites is proposed in a polar sun synchronous dawn to dusk orbit at an altitude of approximately 1 km above the earth. Each mirror satellite contains a multitude of 2 axis tracking mirror segments that collectively direct a sun beam down at a target solar electric field site delivering a solar intensity to that terrestrial site equivalent to the normal daylight sun intensity extending the sunlight hours at that site at dawn and at dusk each day. Each mirror satellite in the constellation consists of a linear string of mirror elements and each terrestrial solar electric field site has a 10 km diameter and can produce approximately 5 GW per terrestrial site. Assuming that in 10 years, there will be approximately 40 terrestrial solar electric field sites evenly distributed in sunny locations near cities around the world, this system can produce more affordable solar electric power during the day and further into the morning and evening hours. The typical operating hours or power plant capacity factor for a terrestrial solar electric power site can thus be extended by about 30%. Assuming a launch cost of $400/kg as was assumed in a recent NASA Space Power Satellite study for future launch costs, the mirror constellation pay back time will be less than 1 year. A logical continuation of this space mirror satellite concept can potentially lead to solar electric power at a cost under 6 ¢ per kWh. © 2012 IEEE. Source
Fraas L.M.,JX Crystals Inc.
2014 IEEE 40th Photovoltaic Specialist Conference, PVSC 2014
A steel mill extrudes steel billets at temperatures above 1400 °C continuously 24 hours a day. The steel billets then go to cooling beds where they slowly cool down to below 1100 °C. JX Crystals Inc makes Gallium Antimonide (GaSb) thermophotovoltaic (TPV) cells that can generate over 1 W/cm2 when exposed to infrared radiant energy from glowing steel at temperatures above 1100 °C. There is a great opportunity to integrate GaSb TPV receivers into steel mill operations to generate electricity economically utilizing this now wasted radiant energy. © 2014 IEEE. Source