The Elements of Innovation Discovered
The Elements of Innovation Discovered
Metal Tech News - November 26, 2024
Rice University scientists drew insights from quantum physics to selectively pluck photons and control the brightness and bandwidth of light sent to a photovoltaic cell for conversion to electricity.
A thermal emitter (left) developed by Rice University engineers composed of a tungsten metal sheet, a thin layer of spacer material and a network of silicon nanocylinders promises efficiencies of over 60%. Professor Gururaj Naik (right) inspects reactor used to test thermal emitter.
Reactor (left) used to test the new thermal emitter; Prof. Gururaj Naik (right) in his lab at Rice University.
Scientists at Rice University have delved into the realm of quantum physics to develop a highly efficient thermal emitter that provides macro-world solutions for capturing and storing clean energy.
Built on a platform made of tungsten, the thermal emitter developed by the Rice research team is a key component of thermophotovoltaic (TPV) systems, which convert heat into light and light into electricity.
An efficient TPV system elevates the prospects for storing clean but intermittent renewable energy as heat, which can be converted to electricity when needed. Such a thermal storage system would offer an alternative to lithium-ion and other battery technologies for grid-scale energy storage.
A highly efficient TPV system could also be used to convert waste heat from industrial processes into clean electricity, a solution that could lower both carbon dioxide emissions and manufacturing costs. To put this potential in context, it is estimated that somewhere between 20 and 50% of heat used to upgrade raw materials into consumer goods is currently being wasted, costing the United States economy over $200 billion annually.
Traditionally, however, TPV systems with the potential to harvest this heat have fallen into two camps – inefficient or impractical.
"Using conventional design approaches limits thermal emitters' design space, and what you end up with is one of two scenarios: practical, low-performance devices or high-performance emitters that are hard to integrate in real-world applications," said Gururaj Naik, an associate professor of electrical and computer engineering at Rice.
A thermal emitter (left) developed by Rice University engineers composed of a tungsten metal sheet, a thin layer of spacer material and a network of silicon nanocylinders promises efficiencies of over 60%. Professor Gururaj Naik (right) inspects reactor used to test thermal emitter.
Naik and his team leaned into quantum physics to develop a new thermal emitter that promises efficiencies of over 60% and is ready for real-world applications.
"We essentially showed how to achieve the best possible performance for the emitter given realistic, practical design constraints," said Ciril Samuel Prasad, a former Ph.D. student of Naik's who has since earned a doctorate in electrical and computer engineering from Rice and has taken on a role as a postdoctoral research associate at Oak Ridge National Laboratory.
The emitter designed by the Rice researchers has a tungsten metal sheet base, a thin layer of spacer material, and a network of silicon nanocylinders. When heated, the base layers accumulate thermal radiation, which can be thought of as a bath of photons. The tiny resonators sitting on top "talk" to each other in a way that allows them to "pluck photon-by-photon" from this bath, controlling the brightness and bandwidth of the light sent to a photovoltaic (PV) solar cell.
The photon selectivity that makes this TPV system so efficient was achieved through insights from quantum physics.
"Instead of focusing on the performance of single-resonator systems, we instead took into account the way these resonators interact, which opened up new possibilities," Naik explained. "This gave us control over how the photons are stored and released."
Reactor (left) used to test the new thermal emitter; Prof. Gururaj Naik (right) in his lab at Rice University.
The Rice scientists believe their TPV system could be pushed above the current 60% efficiency with the use of new materials with better properties.
Higher efficiency would make thermal storage built around this system designed to be plugged into real-world applications more competitive with lithium-ion batteries and other more traditional storage technologies, particularly in scenarios where long-term energy storage is needed.
With the ability to convert a significant amount of the heat wasted by industrial processes and the production of electricity at nuclear and other power plants, the TPV system designed by the scientists at Rice could fill in a much-needed gap in the transition to net-zero emissions energy.
"Based on my own experience working with NASA and launching a startup in the renewable energy space, I think that energy conversion technologies are very much in need today," said Naik.
Beyond providing a clean energy storage and conversions system here on Earth, the Rice team believes their TPV technology could be used in space applications such as powering rovers on Mars.
"If our approach could lead to an increase in efficiency from 2% to 5% in such systems, that would represent a significant boost for missions that rely on efficient power generation in extreme environments," the Rice electrical and computer engineering professor said.
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