X-Message-Number: 21074
Date: Thu, 06 Feb 2003 23:34:11 +0100
From: Henri Kluytmans <>
Subject: Energy costs of MNT made objects

Thomas Donaldson wrote :

>The energy used to make an object is not the same as the energy
>which may be stored in the object. 

Yes, but in this case the chemical energy stored in the object 
accounts for the bulk of the energy required to make the object, 
and I did mention that somewhere. 

Quote :
"I did not include the cooling part of the device, but on the other hand, 
I took the chemical energy for a volume-equivalent mass of diamond, 
which should make more than good for the omission of the cooling part.
Also the energy cost for transportation of molecules, inefficiencies, 
computation and entropy reduction together are almost ten times less 
than the chemical energy."

(Although I made a mistake here, entropy reduction is not an energy 
cost...)

>You discuss diamonds as materials for nanotech devices. Fine. 

I did use diamond for simplicity, because a solid block of diamond 
will certainly require more energy to make than a diamondoid nanodevice 
of the same volume.

>What chemical (and other) energies are used in making those 
>diamonds, remembering that some of that energy will be lost 
>and not recoverable from the diamonds themselves?

I'll try to give a more complete list of energies involved in 
every part of the manufacturing process in another posting. 
(Because it will take some time.)

Of course you could gather that information yourself by 
obtaining the book Nanosystems and looking it up.

>You do not cite any work which looks at this question. To be fair, we

The book "Nanosystems" of course !!!!  ( See chapter 13 & 14 )

>have no nanotech devices of the kind you envision which would let
>us use experiments to work out this energy. 

Indeed, there are no functioning devices yet. But theoretical 
calculations should result in good estimations, because the 
science behind the processes is all very well known. 

>A valid argument for nanotech substitutes for red blood cells 
>would calculate the energy needed to make them, not just the 
>energy that remains with them after they're made.

The total energy required for all other operational steps is about 
a factor 10 less (and this could probably be improved, for example 
by slowing down the process).

Even if these other manufacturing operations would take a 100 times 
more energy then assumed, the MNT devices would still cost much less 
energy to make then their functional biological equivalents !
Remember that the manufacturing energy cost was 10^4 (respirocytes) 
to 10^7-10^10 (computing device) times better for MNT devices.

Furthermore the human body uses biological feedstock molecules 
(almost completely produced directly or indirectly by plantlife). 
When MNT devices use organic feedstock molecules they can be 
net-energy producers! So maybe, this whole discussion is going a 
little far. Especially concerning the fact that energycosts in 
the MNT era will be negligible compared to now.

But nevertheless I will dig into Nanosystems and try to make a 
more complete list of all the energy costs involved.

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