1. Joined
    26 May '08
    Moves
    2120
    02 Jun '09 14:513 edits
    I wanted to study the chemistry of bioluminescence (natures lighting in the form of chemical energy being converted to light energy in fireflies etc) to asses what hope there is of somehow using a modified version of bioluminescence in our artificial lighting to take advantage of the supposed much greater energy of bioluminescent compared with current artificial lighting.

    The current most energy efficient artificial lighting normally comes from LAD lamps that can run with an energy efficiency as high as 30% but in practice run with much lower efficiency so that means at least 70% of the energy we use for our lighting is simply wasted. But I have heard that bioluminescence typically has an energy efficiency of 96%. So my idea I want to asses is what hope there is of taking the chemistry of bioluminescence and modifying the key organic molecules involved so that instead of converting chemical energy to light energy it converts electrical energy to light energy so that you can simply put it into a lamp or bulb to make the lighting have an impressive ~96% energy efficiency.

    But the problem now is that I am worried that the usual claim that bioluminescence in nature can have an energy efficiency of 96% just might be highly misleading because I am not sure if that doesn’t take into account the energy needed to create the reactants of the chemical reaction that creates light and ONLY takes into account the efficiency of the conversion of chemical energy into light energy only AFTER those reactants have been made? -could somebody who is an expert on this clarify if this is or is not the case?

    The reason why I got that impression is because it said in:

    http://serendip.brynmawr.edu/exchange/node/1721

    “…The light that a firefly creates is the result of a combination of four different ingredients. This light is produced through a chemical reaction involving Luciferin, which is a substrate, Luciferase, an enzyme, ATP, and oxygen

    the Luciferin will then oxidize and activate the Luciferase.

    …”


    -and it said in another web site that when Luciferin oxidises it produces a molecule of CO2 and the ATP is converted to ADP.
    But here’s the problems; surely it takes not only energy to change that ADP back into ATP to then produce more light but living cells can only do that energy conversion with an energy efficiency of about 69%? (this 69% is assuming glucose is fully oxidised in aerobic respiration to convert the ADP back into ATP)
    I am not sure if I can really make the energy efficiency of 96% claim for bioluminescence make mathematical sense if that claim takes this 69% energy efficiency of ADP to ATP conversion into account -so does this claim take this into account?

    And as Luciferin is partly oxidised in the process (and produces a molecule of CO2 so it must loose a carbon atom somewhere) then that would mean a new Luciferin will have to be made up for the creature to bioluminescent again and I presume (and please will somebody correct me if I am wrong) this occurs by reducing the partly oxidised Luciferin to convert it back and recycle it ready to be used again next time? But that would surely involve the transfer of chemical energy with a limited energy efficiency -does this energy efficiency of 96% claim for bioluminescence take into account that limited energy efficiency of converting the partly oxidised Luciferin back to how it was?
  2. Cape Town
    Joined
    14 Apr '05
    Moves
    52945
    04 Jun '09 06:23
    Originally posted by Andrew Hamilton
    The current most energy efficient artificial lighting normally comes from LAD lamps that can run with an energy efficiency as high as 30% but in practice run with much lower efficiency so that means at least 70% of the energy we use for our lighting is simply wasted.
    What is a LAD lamp? If it was a typo and you meant LED, some sites claim that LEDs are no more efficient than incandescents and way less efficient than fluorescents.
  3. Joined
    26 May '08
    Moves
    2120
    04 Jun '09 10:321 edit
    Originally posted by twhitehead
    What is a LAD lamp? If it was a typo and you meant LED, some sites claim that LEDs are no more efficient than incandescents and way less efficient than fluorescents.
    …What is a LAD lamp?


    Sorry, you are right; should have been “LED”.

    …some sites claim that LEDs are no more efficient than incandescents and way less efficient than fluorescents.
    ..…


    Yes, because it depends whether or not you take into account such factors such as its operating temperature (which often has to be kept high by running the LED at higher voltage that makes it run inefficiently) when stating its energy efficiency.

    http://en.wikipedia.org/wiki/Compact_fluorescent_lamp

    “…LED lamps presently have efficiencies of 30% with higher levels attainable…”

    “…A typical CFL (compact fluorescent lamp) is in the range of 17 to 21% efficient at converting electric power to radiant power…”

    But the above doesn’t take into account of the required operating temperature etc thus that is why I said in my post:

    “…. The current most energy efficient artificial lighting normally comes from LED lamps that can run with an energy efficiency as high as 30% BUT in practice run with much lower efficiency…” (my emphasis and spelling corrected)