<story><title>Rice University researchers propose a way to boost solar efficiency</title><url>https://polyarch.co/rice-university-research-heat-into-light/</url></story><parent_chain></parent_chain><comment><author>apo</author><text>The title is misleading. The full title is:&lt;p&gt;&amp;gt; Researchers at Rice University developed a method to convert heat into light that could boost solar efficiency from 22% to 80%&lt;p&gt;The conditional tense signals that the researchers didn&amp;#x27;t actually do so, but that the study might enable it. The article re-iterates that this is speculation:&lt;p&gt;&amp;gt; The implications of their discovery are significant. Research from Chloe Doiron, a Rice graduate student, revealed that 20% of industrial energy consumption is wasted through heat. It could also mean an increase in the efficiency of solar cells, which are currently only 22% efficient at their peak. Recycling the thermal energy from solar cells using carbon nanotube technology could increase the efficiency to 80% according to the researchers. ...</text></comment>
<story><title>Rice University researchers propose a way to boost solar efficiency</title><url>https://polyarch.co/rice-university-research-heat-into-light/</url></story><parent_chain></parent_chain><comment><author>amluto</author><text>As far as I can tell, this is functionally just a coating with low emittance in the IR outside a narrow band. A matched PV device that is kept cool can, in principle, approach the Carnot efficiency for the temperature difference between the emitter and the PV junction.  If the emitter is the sun, then the source temperature is very high and the Carnot efficiency isn’t a major limit. If the source is a solar panel, I’m having a hard time seeing how this is useful.&lt;p&gt;I can see this being somewhat useful as a no-moving-parts heat engine for something like a solar concentrator, but there’s another relevant thermodynamic limit: even if this magic material has emissivity 1, it won’t radiate at a greater power per unit area than the blackbody spectrum predicts. At non-crazy temperatures, this is not very high, which will limit output for small things like solar concentrator targets.&lt;p&gt;So I can see this being useful to convert waste industrial heat, or maybe as a bottoming engine for a combined cycle plant, but I am having trouble understanding how it could be useful for solar.</text></comment>