Can plants/solar panels decrease entropy?

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    decrease Entropy
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Discussion Overview

The discussion revolves around the potential for plants and solar panels to decrease entropy through the conversion of heat into usable energy, particularly in the context of refrigerators and the nature of light absorption by plants. It explores theoretical scenarios, the efficiency of energy conversion, and the implications of thermodynamic laws.

Discussion Character

  • Exploratory
  • Debate/contested
  • Technical explanation

Main Points Raised

  • Some participants propose that a highly efficient refrigerator could potentially allow plants or solar panels to convert waste heat into usable energy faster than the refrigerator consumes energy.
  • Others argue that the entropy created by the sun in producing light means that plants cannot decrease entropy in this context.
  • One participant questions the feasibility of a refrigerator's heat sink reaching temperatures that would emit light, suggesting that such a scenario would indicate a malfunction.
  • There is a discussion about the conversion of light waves into chemical energy by plants, with a focus on the limitations of infrared light absorption and the lack of a specific wavelength threshold for energy conversion.
  • A participant raises a theoretical question about whether converting heat into chemical or electrical energy could violate the second law of thermodynamics, particularly regarding temperature differences.
  • Another participant explains that plants utilize low-entropy energy from visible light for photosynthesis while emitting high-entropy energy as heat, indicating the role of energy differences in their chemical reactions.

Areas of Agreement / Disagreement

Participants express multiple competing views on the potential for plants and solar panels to decrease entropy, the nature of light absorption by plants, and the implications of thermodynamic principles. The discussion remains unresolved with no consensus reached.

Contextual Notes

Participants note the complexity of energy conversion processes and the limitations of theoretical scenarios presented, including assumptions about efficiency and the nature of heat transfer.

schiz0ai
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If in theory there was a very efficient and powerfull refrigerator.

Is it possible that a plant/solar panel could turn that heat into usuable energy, faster then what the frige uses up?
 
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The sun created a lot of entropy to makee that light, so no.
 
im not talking about the sun, i mean the refrigerators heat sink becoming hot enough to radiate light that can be converted by the plant/solarcell
 
schiz0ai said:
im not talking about the sun, i mean the refrigerators heat sink becoming hot enough to radiate light that can be converted by the plant/solarcell

If my fridge/ freezer was getting that hot that it was emitting light i would be switching it off before it burst into flames. It would have to be seriously faulty

Dave
 
schiz0ai said:
If in theory there was a very efficient and powerfull refrigerator.

Is it possible that a plant/solar panel could turn that heat into usuable energy, faster then what the frige uses up?

You could build a heat engine that uses the waste heat of a refrigerator to produce power, but it would only be a fraction of what the fridge is using.
 
So its possible for normal light waves to be converted into chemical energy by plants, but not for infra red spectrum? Where is this so called "wavelength" point where suddenly light can or can no longer be converted? Give me a number if possible, and please keep it theoretical.
 
schiz0ai said:
So its possible for normal light waves to be converted into chemical energy by plants, but not for infra red spectrum? Where is this so called "wavelength" point where suddenly light can or can no longer be converted? Give me a number if possible, and please keep it theoretical.

Not sure why it needs to be kept theoretical, this is a very real thing that happens everyday. But to answer your question, there is no single number for the wavelength that plants simply stop converting. If you were to graph the spectrum that is absorbed by the plant it would taper off gradually as you get to longer and longer wavelengths on the red end. By about 700 nanometers the absorption is "practically zero". This corrosponds with the very far end of the visible spectrum and the start of the "near infrared" section.
 
If there was a device that could convert heat into chemical/electrical energy at a decent rate, even at "relatively low" temperatures.
The heat would still flow from hot to the colder(device).
But the exact moment a bit of heat is converted into a chemical bond, the temperature difference between the room and the device wil lincrease.
Would that violate the 2nd law of thermal dynamics?
 
  • #10
Plants can direct their chemical reactions because they have a source of low-entropy energy (energetic photons, as visible light), and can emit high-entropy energy (heat, for example as infrared photons) - the difference allows them to use some fraction of the energy for photosynthesis.
If you try to use infrared radiation both as input and output, your chemical reactions will always end in some equilibrium and you cannot extract energy.
 
  • #11
Thanks for the info about plants, i didnt know exactly how they worked.
 

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