Graphene heat pipe...

[Carl]

Researchers have constructed a heat pipe made from graphene that dissipates
about 3.5 times more heat than commercial copper heat pipes. It\'s also much
lighter and waaaay more expensive . It uses a plasma etched layer of
carbon fibers as the internal wicking surface and a mix of water/ethanol as
the working fluid. See:
https://onlinelibrary.wiley.com/doi/10.1002/nano.202000195 for the full
paper.

--
Regards,
Carl Ijames

 

[Liz Tuddenham]

Carl <carl.ijamesXYZ@ZYXverizon.net> wrote:

Researchers have constructed a heat pipe made from graphene that dissipates
about 3.5 times more heat than commercial copper heat pipes.

Does it actually claim to dissipate heat? I thought heat pipes just
conducted heat to be dissipated elsewhere.


--
~ Liz Tuddenham ~
(Remove the \".invalid\"s and add \".co.uk\" to reply)
www.poppyrecords.co.uk

 

[Rick C]

On Tuesday, December 8, 2020 at 6:20:36 AM UTC-5, Liz Tuddenham wrote:

Carl <carl.ij...@ZYXverizon.net> wrote:

Researchers have constructed a heat pipe made from graphene that dissipates
about 3.5 times more heat than commercial copper heat pipes.
Does it actually claim to dissipate heat? I thought heat pipes just
conducted heat to be dissipated elsewhere.

I\'m a bit puzzled by the claims. They talk about the working fluid just like in any other heat pipe. In those pipes it is the working fluid that carries the heat. So why does anyone care about the pipe casing? Is this heat pipe just a thermal conductor with a working fluid to lubricate the non-moving parts? How is the graphene actually helping the thermal properties, by adding to the working fluid?

--

Rick C.

- Get 1,000 miles of free Supercharging
- Tesla referral code - https://ts.la/richard11209

 

[Rick C]

On Tuesday, December 8, 2020 at 6:20:36 AM UTC-5, Liz Tuddenham wrote:

Carl <carl.ij...@ZYXverizon.net> wrote:

Researchers have constructed a heat pipe made from graphene that dissipates
about 3.5 times more heat than commercial copper heat pipes.
Does it actually claim to dissipate heat? I thought heat pipes just
conducted heat to be dissipated elsewhere.

I\'m a bit puzzled by the claims. They talk about the working fluid just like in any other heat pipe. In those pipes it is the working fluid that carries the heat. So why does anyone care about the pipe casing? Is this heat pipe just a thermal conductor with a working fluid to lubricate the non-moving parts? How is the graphene actually helping the thermal properties, by adding to the working fluid?

--

Rick C.

- Get 1,000 miles of free Supercharging
- Tesla referral code - https://ts.la/richard11209

 

[George Herold]

On Monday, December 7, 2020 at 5:33:06 PM UTC-5, Carl wrote:

Researchers have constructed a heat pipe made from graphene that dissipates
about 3.5 times more heat than commercial copper heat pipes. It\'s also much
lighter and waaaay more expensive . It uses a plasma etched layer of
carbon fibers as the internal wicking surface and a mix of water/ethanol as
the working fluid. See:
https://onlinelibrary.wiley.com/doi/10.1002/nano.202000195 for the full
paper.

--
Regards,
Carl Ijames

I didn\'t read all of it, but it looks like the 3.5 times better is in terms of weight.
It\'s only \'better\' \'cause it\'s lighter.

George H.

 

[George Herold]

On Monday, December 7, 2020 at 5:33:06 PM UTC-5, Carl wrote:

Researchers have constructed a heat pipe made from graphene that dissipates
about 3.5 times more heat than commercial copper heat pipes. It\'s also much
lighter and waaaay more expensive . It uses a plasma etched layer of
carbon fibers as the internal wicking surface and a mix of water/ethanol as
the working fluid. See:
https://onlinelibrary.wiley.com/doi/10.1002/nano.202000195 for the full
paper.

--
Regards,
Carl Ijames

I didn\'t read all of it, but it looks like the 3.5 times better is in terms of weight.
It\'s only \'better\' \'cause it\'s lighter.

George H.

 

[server]

On Tue, 8 Dec 2020 11:18:22 +0000, liz@poppyrecords.invalid.invalid
(Liz Tuddenham) wrote:

Carl <carl.ijamesXYZ@ZYXverizon.net> wrote:

Researchers have constructed a heat pipe made from graphene that dissipates
about 3.5 times more heat than commercial copper heat pipes.

Does it actually claim to dissipate heat?

Many times.

I thought heat pipes just
conducted heat to be dissipated elsewhere.

Exactly. And the mechanism isn\'t thermal conduction, it\'s vapor
transport.

Heat pipes are usually skinny, so the radial heat flux is large at
their active surface. Graphene only conducts heat well in-plane, and
the planes are microns thick.





--

John Larkin Highland Technology, Inc

The best designs are necessarily accidental.

 

[server]

On Tue, 8 Dec 2020 11:18:22 +0000, liz@poppyrecords.invalid.invalid
(Liz Tuddenham) wrote:

Carl <carl.ijamesXYZ@ZYXverizon.net> wrote:

Researchers have constructed a heat pipe made from graphene that dissipates
about 3.5 times more heat than commercial copper heat pipes.

Does it actually claim to dissipate heat?

Many times.

I thought heat pipes just
conducted heat to be dissipated elsewhere.

Exactly. And the mechanism isn\'t thermal conduction, it\'s vapor
transport.

Heat pipes are usually skinny, so the radial heat flux is large at
their active surface. Graphene only conducts heat well in-plane, and
the planes are microns thick.





--

John Larkin Highland Technology, Inc

The best designs are necessarily accidental.

 

[Carl]

wrote in message news:ebavsflo7nnlgflitjffo33icdp3ckup0t@4ax.com...

On Tue, 8 Dec 2020 11:18:22 +0000, liz@poppyrecords.invalid.invalid
(Liz Tuddenham) wrote:

Carl <carl.ijamesXYZ@ZYXverizon.net> wrote:

Researchers have constructed a heat pipe made from graphene that
dissipates
about 3.5 times more heat than commercial copper heat pipes.

Does it actually claim to dissipate heat?

Many times.

I thought heat pipes just
conducted heat to be dissipated elsewhere.

Exactly. And the mechanism isn\'t thermal conduction, it\'s vapor
transport.

Heat pipes are usually skinny, so the radial heat flux is large at
their active surface. Graphene only conducts heat well in-plane, and
the planes are microns thick.

They also talk about allowing a higher power density, so my impression was
that the gains came both from better conduction of heat from the outside
wall to the fluid inside, and perhaps better conduction of heat up the wall
until it could get transferred to the inside. I\'m no expert on this, I just
thought it was interesting. It\'s graphene, it has to be better . I\'m
sure some PC overclocker will be bragging about upgrading from water cooling
to them within a year . Think how much lighter your laptop could be - at
least a couple of grams.

--
Regards,
Carl Ijames

 

[server]

On Tue, 8 Dec 2020 12:07:17 -0500, \"Carl\"
<carl.ijamesXYZ@ZYXverizon.net> wrote:

wrote in message news:ebavsflo7nnlgflitjffo33icdp3ckup0t@4ax.com...

On Tue, 8 Dec 2020 11:18:22 +0000, liz@poppyrecords.invalid.invalid
(Liz Tuddenham) wrote:

Carl <carl.ijamesXYZ@ZYXverizon.net> wrote:

Researchers have constructed a heat pipe made from graphene that
dissipates
about 3.5 times more heat than commercial copper heat pipes.

Does it actually claim to dissipate heat?

Many times.

I thought heat pipes just
conducted heat to be dissipated elsewhere.

Exactly. And the mechanism isn\'t thermal conduction, it\'s vapor
transport.

Heat pipes are usually skinny, so the radial heat flux is large at
their active surface. Graphene only conducts heat well in-plane, and
the planes are microns thick.

They also talk about allowing a higher power density, so my impression was
that the gains came both from better conduction of heat from the outside
wall to the fluid inside, and perhaps better conduction of heat up the wall
until it could get transferred to the inside. I\'m no expert on this, I just
thought it was interesting. It\'s graphene, it has to be better . I\'m
sure some PC overclocker will be bragging about upgrading from water cooling
to them within a year . Think how much lighter your laptop could be - at
least a couple of grams.

You can buy pyrolytic graphite sheets from Digikey. They have high
thermal conductivity, but only in the plane axis, and are thin, so are
basically useless.



--

John Larkin Highland Technology, Inc

The best designs are necessarily accidental.

 

[server]

On Tue, 8 Dec 2020 12:07:17 -0500, \"Carl\"
<carl.ijamesXYZ@ZYXverizon.net> wrote:

wrote in message news:ebavsflo7nnlgflitjffo33icdp3ckup0t@4ax.com...

On Tue, 8 Dec 2020 11:18:22 +0000, liz@poppyrecords.invalid.invalid
(Liz Tuddenham) wrote:

Carl <carl.ijamesXYZ@ZYXverizon.net> wrote:

Researchers have constructed a heat pipe made from graphene that
dissipates
about 3.5 times more heat than commercial copper heat pipes.

Does it actually claim to dissipate heat?

Many times.

I thought heat pipes just
conducted heat to be dissipated elsewhere.

Exactly. And the mechanism isn\'t thermal conduction, it\'s vapor
transport.

Heat pipes are usually skinny, so the radial heat flux is large at
their active surface. Graphene only conducts heat well in-plane, and
the planes are microns thick.

They also talk about allowing a higher power density, so my impression was
that the gains came both from better conduction of heat from the outside
wall to the fluid inside, and perhaps better conduction of heat up the wall
until it could get transferred to the inside. I\'m no expert on this, I just
thought it was interesting. It\'s graphene, it has to be better . I\'m
sure some PC overclocker will be bragging about upgrading from water cooling
to them within a year . Think how much lighter your laptop could be - at
least a couple of grams.

You can buy pyrolytic graphite sheets from Digikey. They have high
thermal conductivity, but only in the plane axis, and are thin, so are
basically useless.



--

John Larkin Highland Technology, Inc

The best designs are necessarily accidental.

 

[Clifford Heath]

On 8/12/20 10:18 pm, Liz Tuddenham wrote:

Carl <carl.ijamesXYZ@ZYXverizon.net> wrote:

Researchers have constructed a heat pipe made from graphene that dissipates
about 3.5 times more heat than commercial copper heat pipes.

Does it actually claim to dissipate heat? I thought heat pipes just
conducted heat to be dissipated elsewhere.

The rules of thermodynamics don\'t allow heat to be conducted elsewhere
without dissipating it. There has to be a thermal gradient or there\'s no
conduction, and that\'s what dissipation is.

 

[John Larkin]

On Wed, 9 Dec 2020 09:10:55 +1100, Clifford Heath <no.spam@please.net>
wrote:

On 8/12/20 10:18 pm, Liz Tuddenham wrote:
Carl <carl.ijamesXYZ@ZYXverizon.net> wrote:

Researchers have constructed a heat pipe made from graphene that dissipates
about 3.5 times more heat than commercial copper heat pipes.

Does it actually claim to dissipate heat? I thought heat pipes just
conducted heat to be dissipated elsewhere.

The rules of thermodynamics don\'t allow heat to be conducted elsewhere
without dissipating it. There has to be a thermal gradient or there\'s no
conduction, and that\'s what dissipation is.

If heat is transported in a highly conductive rod that is well
insulated, where is it dissipated?

Dissipated, to me, means dispersal into the ambient environment.
That\'s what heat sinks do. Transport doesn\'t do that.

 

[Lasse Langwadt Christensen]

tirsdag den 8. december 2020 kl. 23.11.03 UTC+1 skrev Clifford Heath:

On 8/12/20 10:18 pm, Liz Tuddenham wrote:
Carl <carl.ij...@ZYXverizon.net> wrote:

Researchers have constructed a heat pipe made from graphene that dissipates
about 3.5 times more heat than commercial copper heat pipes.

Does it actually claim to dissipate heat? I thought heat pipes just
conducted heat to be dissipated elsewhere.
The rules of thermodynamics don\'t allow heat to be conducted elsewhere
without dissipating it. There has to be a thermal gradient or there\'s no
conduction, and that\'s what dissipation is.

but the heat is not dissipated in heat pipe (ideally) it is dissipated in the sink on the other end

 

[Clifford Heath]

On 9/12/20 9:26 am, Lasse Langwadt Christensen wrote:

tirsdag den 8. december 2020 kl. 23.11.03 UTC+1 skrev Clifford Heath:
On 8/12/20 10:18 pm, Liz Tuddenham wrote:
Carl <carl.ij...@ZYXverizon.net> wrote:

Researchers have constructed a heat pipe made from graphene that dissipates
about 3.5 times more heat than commercial copper heat pipes.

Does it actually claim to dissipate heat? I thought heat pipes just
conducted heat to be dissipated elsewhere.
The rules of thermodynamics don\'t allow heat to be conducted elsewhere
without dissipating it. There has to be a thermal gradient or there\'s no
conduction, and that\'s what dissipation is.

but the heat is not dissipated in heat pipe (ideally) it is dissipated in the sink on the other end

What part of the Second Law do you (and JL) have difficulty understanding?

Heat surely is dissipated in the heat pipe, or it could not be
conducted. There is no thermal superconductor, last time I looked. Even
the carbon nanotubes that are touted for the role aren\'t so \"super\".

So it comes down to non-zero thermal resistivities and time constants.
Of course.

 

[John Larkin]

On Wed, 9 Dec 2020 09:10:55 +1100, Clifford Heath <no.spam@please.net>
wrote:

On 8/12/20 10:18 pm, Liz Tuddenham wrote:
Carl <carl.ijamesXYZ@ZYXverizon.net> wrote:

Researchers have constructed a heat pipe made from graphene that dissipates
about 3.5 times more heat than commercial copper heat pipes.

Does it actually claim to dissipate heat? I thought heat pipes just
conducted heat to be dissipated elsewhere.

The rules of thermodynamics don\'t allow heat to be conducted elsewhere
without dissipating it.

What happens if I carry a thermos of hot coffee upstairs? Does that
create dissipation?

Heat pipes transport heated mass.

There has to be a thermal gradient or there\'s no
>conduction, and that\'s what dissipation is.

Transportation doesn\'t need a gradient. It can work against a
gradient.

 

[John Larkin]

On Wed, 9 Dec 2020 09:10:55 +1100, Clifford Heath <no.spam@please.net>
wrote:

On 8/12/20 10:18 pm, Liz Tuddenham wrote:
Carl <carl.ijamesXYZ@ZYXverizon.net> wrote:

Researchers have constructed a heat pipe made from graphene that dissipates
about 3.5 times more heat than commercial copper heat pipes.

Does it actually claim to dissipate heat? I thought heat pipes just
conducted heat to be dissipated elsewhere.

The rules of thermodynamics don\'t allow heat to be conducted elsewhere
without dissipating it. There has to be a thermal gradient or there\'s no
conduction, and that\'s what dissipation is.

If heat is transported in a highly conductive rod that is well
insulated, where is it dissipated?

Dissipated, to me, means dispersal into the ambient environment.
That\'s what heat sinks do. Transport doesn\'t do that.

 

[John Larkin]

On Wed, 9 Dec 2020 09:33:25 +1100, Clifford Heath <no.spam@please.net>
wrote:

On 9/12/20 9:26 am, Lasse Langwadt Christensen wrote:
tirsdag den 8. december 2020 kl. 23.11.03 UTC+1 skrev Clifford Heath:
On 8/12/20 10:18 pm, Liz Tuddenham wrote:
Carl <carl.ij...@ZYXverizon.net> wrote:

Researchers have constructed a heat pipe made from graphene that dissipates
about 3.5 times more heat than commercial copper heat pipes.

Does it actually claim to dissipate heat? I thought heat pipes just
conducted heat to be dissipated elsewhere.
The rules of thermodynamics don\'t allow heat to be conducted elsewhere
without dissipating it. There has to be a thermal gradient or there\'s no
conduction, and that\'s what dissipation is.

but the heat is not dissipated in heat pipe (ideally) it is dissipated in the sink on the other end

What part of the Second Law do you (and JL) have difficulty understanding?

Heat surely is dissipated in the heat pipe, or it could not be
conducted. There is no thermal superconductor, last time I looked. Even
the carbon nanotubes that are touted for the role aren\'t so \"super\".

So it comes down to non-zero thermal resistivities and time constants.
Of course.

We seem to have different definitions of \"dissipated.\"

An insulated truck carrying a load of hot tar at 75 MPH: is that
transportation dissipation?

 

[John Larkin]

On Wed, 9 Dec 2020 09:33:25 +1100, Clifford Heath <no.spam@please.net>
wrote:

On 9/12/20 9:26 am, Lasse Langwadt Christensen wrote:
tirsdag den 8. december 2020 kl. 23.11.03 UTC+1 skrev Clifford Heath:
On 8/12/20 10:18 pm, Liz Tuddenham wrote:
Carl <carl.ij...@ZYXverizon.net> wrote:

Researchers have constructed a heat pipe made from graphene that dissipates
about 3.5 times more heat than commercial copper heat pipes.

Does it actually claim to dissipate heat? I thought heat pipes just
conducted heat to be dissipated elsewhere.
The rules of thermodynamics don\'t allow heat to be conducted elsewhere
without dissipating it. There has to be a thermal gradient or there\'s no
conduction, and that\'s what dissipation is.

but the heat is not dissipated in heat pipe (ideally) it is dissipated in the sink on the other end

What part of the Second Law do you (and JL) have difficulty understanding?

Heat surely is dissipated in the heat pipe, or it could not be
conducted. There is no thermal superconductor, last time I looked. Even
the carbon nanotubes that are touted for the role aren\'t so \"super\".

So it comes down to non-zero thermal resistivities and time constants.
Of course.

We seem to have different definitions of \"dissipated.\"

An insulated truck carrying a load of hot tar at 75 MPH: is that
transportation dissipation?

 

[Clifford Heath]

On 9/12/20 9:35 am, John Larkin wrote:

On Wed, 9 Dec 2020 09:10:55 +1100, Clifford Heath <no.spam@please.net
wrote:

On 8/12/20 10:18 pm, Liz Tuddenham wrote:
Carl <carl.ijamesXYZ@ZYXverizon.net> wrote:

Researchers have constructed a heat pipe made from graphene that dissipates
about 3.5 times more heat than commercial copper heat pipes.

Does it actually claim to dissipate heat? I thought heat pipes just
conducted heat to be dissipated elsewhere.

The rules of thermodynamics don\'t allow heat to be conducted elsewhere
without dissipating it.

What happens if I carry a thermos of hot coffee upstairs? Does that
create dissipation?

Heat pipes transport heated mass.

There has to be a thermal gradient or there\'s no
conduction, and that\'s what dissipation is.

Transportation doesn\'t need a gradient. It can work against a
gradient.

A heat pump requires dissipation elsewhere.

All thermal flow requires dissipation, because that\'s what dissipation is.