Comment Thermodynamics vs Photovoltaics (Score 1) 720
I've done quite a bit of research comparing Solar Stirlings to Photovoltaics. It may be surprising, but under most circumstances, the Stirlings are more efficient. The downside is the huge outlay for the giant dish and engine. Not to mention maintenance costs... you know... moving parts...
However, from those of you who remember your physics classes, consider the thermodynamic efficiency of an engine set between 3000K on one end and around 450K on the other. If you do the math, you get well more than 30% input efficiency. Naturally, no engine is perfect, however these Solar Stirlings are very nice. The only friction on the "plunger" is with the working gas.
Compare this to photovoltaics. Under laboratory conditions, the best photovoltaic designs at best only equal thermodynamic efficiency. On the plus side, the outlay is much less, with the caveat that they all wear out in 20-25 years.
The important point here is that theoretical PV efficiency is 100%. In fact, if you look at nature, you'll find deep-ocean organisms that convert light at efficiencies well above that of current PV technology.
So for now, thermodynamics. However, assuming PV keeps getting better (quantum dots?), the future will belong to PV.
However, from those of you who remember your physics classes, consider the thermodynamic efficiency of an engine set between 3000K on one end and around 450K on the other. If you do the math, you get well more than 30% input efficiency. Naturally, no engine is perfect, however these Solar Stirlings are very nice. The only friction on the "plunger" is with the working gas.
Compare this to photovoltaics. Under laboratory conditions, the best photovoltaic designs at best only equal thermodynamic efficiency. On the plus side, the outlay is much less, with the caveat that they all wear out in 20-25 years.
The important point here is that theoretical PV efficiency is 100%. In fact, if you look at nature, you'll find deep-ocean organisms that convert light at efficiencies well above that of current PV technology.
So for now, thermodynamics. However, assuming PV keeps getting better (quantum dots?), the future will belong to PV.
