I wrote:
The algae converts waste heat back into carbon compounds, recovering
some of the lost energy.
That is stupid way to express the idea. It should be:
The algae uses IR from the waste heat to synthesize carbon compounds,
converting some waste heat back into high-grade potential chemical energy.
It is unclear to me what the overall efficiency of this conversion
process is. For plants using white sunlight, it is on the order of 1%
or 2% as I said. For lettuce provided with only PAR in ideal growing
conditions at the Japanese food factory, it can go up to ~15%, but
you have to convert all of the light into the right wavelength.
One source says: "The chlorosome of vent-dwelling green sulfur
bacteria makes them the world champions at garnering photons." I
assume that means it is somewhere up around 5% or 10%, but I do not
know. Looking up green-sulfur bacteria energy efficiency, I found
some sources that say:
"The efficiency of energy transfer from carotenoid to
bacteriochlorophyll a in the RC core complex was 23% at 6 K, and from
the FMO-protein to the core it was 35%. . . ." I assume this
describes a multi-stage process with 8% efficiency overall.
In 1952, someone concluded: "These results are considered as support
for the view that also in the bacterial photosyntheses the primary
photochemical reaction consists in the photolysis of H2O, and that
the chemical energy released during the oxidation of the electron
donor is not utilized for CO2 assimilation. Hence the photosynthetic
processes of the green sulfur bacteria are thermodynamically less
efficient than is green plant photosynthesis."
By the way, the initial "excitron" capture phase for any
photosynthetic process is astoundingly efficient. If only we could
make thermoelectric generators this good!
These bacteria tolerate remarkably high temperatures.
- Jed
