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A family member shared an article about thermovoltaics being developed at MIT with support from National Renewable Energy Lab (NREL).
The article mentions that the "design can generate electricity from a heat source of between 1,900 to 2,400 degrees Celsius, or up to about 4,300 degrees Fahrenheit."
Not too many materials are solid at those temperatures. Graphite (carbon) is mentioned as the material in the hottest part. "The system would absorb excess energy from renewable sources such as the sun and store that energy in heavily insulated banks of hot graphite."
Forms of carbon are relatively inexpensive compare to exotic refractory metals and ceramics.
Otherwise, only tungsten (mp 3410°C), rhenium (3180°C), osmium (3045°C), tantalum (2996°C), or some compound, or carbide (e.g., a carbide of Ta or Hf, or both) would be capable of handling temperatures up around 2400°C. While Mo has a melting point of 2617°C, it would creep/flow at 2400°C if there were any appreciable load/stress.
Melting points of carbides are approximately: 3887°C (HfC), 3875°C (TaC), 3532-3550°C (ZrC), 3480-3500°C (NbC), 3140°C (TiC), and 2830° C (VC). Of course, one has to look at the thermochemical/thermodynamic stability of the metals or compounds at such temperatures.
A new heat engine with no moving parts is as efficient as a steam turbine
https://news.mit.edu/2022/thermal-heat-engine-0413The article mentions that the "design can generate electricity from a heat source of between 1,900 to 2,400 degrees Celsius, or up to about 4,300 degrees Fahrenheit."
Not too many materials are solid at those temperatures. Graphite (carbon) is mentioned as the material in the hottest part. "The system would absorb excess energy from renewable sources such as the sun and store that energy in heavily insulated banks of hot graphite."
Forms of carbon are relatively inexpensive compare to exotic refractory metals and ceramics.
Otherwise, only tungsten (mp 3410°C), rhenium (3180°C), osmium (3045°C), tantalum (2996°C), or some compound, or carbide (e.g., a carbide of Ta or Hf, or both) would be capable of handling temperatures up around 2400°C. While Mo has a melting point of 2617°C, it would creep/flow at 2400°C if there were any appreciable load/stress.
Melting points of carbides are approximately: 3887°C (HfC), 3875°C (TaC), 3532-3550°C (ZrC), 3480-3500°C (NbC), 3140°C (TiC), and 2830° C (VC). Of course, one has to look at the thermochemical/thermodynamic stability of the metals or compounds at such temperatures.