a question

[Lc_shi]

Hi dear sir
Two container linked with pipe and all system are sealed. If the T2>T1,the media is water or others, how about the heat transfer? the heat can flow from T2 to T1 side? pls advise. thx!

attached drawing

regards
LC

[Brian_UK]

Assuming that the pipe connections are on the top and at the bottom of the containers then convection current will move the fluid from T2 into T1 until the temperature equalizes when movement will stop.

[Abby Normal]

Elevate the hotter tank by about 2 feet and you have a thermosiphon similar to a gravity solar water heater

it would require external heat added to the upper tank to keep it going

[Peter_1]

LCShi, I agree with Brian.
This principle was used by Mitsubishi Electric in AC's they specially made for telecom switching cabines like we see many times along highways.
They sometimes publish new things in a newspaper and this article was in one of them some years ago.
It is something they mass produce already but it isn't available here...;)yet.
Just like their small CO2 heat pumps.

[chemi-cool]

The heat will flow but will take a loooooooooong time.

[Lc_shi]

Ya,Chemi ,
But what to do to make it quick? This is the question!

regards
LC

[chemi-cool]

A pump.......

[Lc_shi]

abosolutely right.

Maybe the heat pipe can meet this purpose. Without phase change,the pump is necessary. who knows something about heat pipe? I need a teacher:)

[chemi-cool]

Read and learn.....

http://www.cheresources.com/htpipes.shtml

I will test you later..............

[GXMPLX]

Yes, if there is no work or heat exchanged to the surroundings the second law of thermodynamics states that energy will flow from container at T2 to T1 and not the other way until a state of equilibrium is reached (lower T2 higher T1). This is independent of the fluid.

[Peter_1]

Heat pipes are used also in return ducts http://ee.emsd.gov.hk/english/air/air_technology/air_tech_air.html
Heatpipes are widely used here on roofs to heat domestic water