Talk:Heat pipeline

From Renewable Energy Design

Text here was copied from Archimerged's user talk page.

[edit] Heat pipe question

Why can't I build a heat pipe from Death Valley up the nearby mountain and so get a fairly large delta-T at the top of the mountain? Or from the bottom of the Homestake mine to the top of the nearby mountain?

I suppose it has to do with insulation efficiency. The theoretical heat pipe is evacuated and perfectly insulated, filled with the right amount of refrigerant so that condensed liquid runs downward (perhaps in a separate small drainpipe to keep from cooling the vapor) and vapor at the hot temperature moves quickly to fill in the space vacated by condensed vapor. Condensation only occurs at the top of the mountain, not along the mile or two long pipeline leading from the hot location up the mountain.

Actually, I guess the problem would be reasonable cost insulation cannot prevent continued condensation below the top. How do I calculate this? I guess I know: look up the coefficient of heat transfer for various types of insulation, figure the actual area of pipe needing insulation, and figure how much heat will leak out along the way to the mountain top. Archimerged 02:38, 13 Jan 2006 (UTC)

First and foremost is co$t. Secondly the temperature in the mine is not all that high, and the variable low temperatures at the top of the mountain would have a considerable range. Death valley would be a better heat source but here again the temperature varies over a wide range. Heat pipes require more or less stable and limited temperatures due to HT agent requirements. An inclined mountainside H.P. might not work at all. Required pipe size for physical reasons combined with other considerations make this a financial disaster. User:NotSCarnot 17:52, 2 July 2006 (UTC)

I believe that I could write specifications for a vacuum insulated pipe line to house a heat pipe of any reasonable length to transport heat from a low lying desert location or mine depths to a nearby mountain top. I doubt that you would want to pay the cost nor could you find anyone willing to finance it for you. The ROI would be too far negative! User:NotSCarnot 02:00 4 July 2006 (UTC)

Archimerged had a discussion about this idea with the denizens of Chevron's discussion site. See some of the links on User:Archimerged, in particular, [1]. It seems that some small hope might arise because of the possibility of running a turbine in the refrigerant return pipe, which would have a very large head if filled with liquid all the way to the top.

There are Heat Pipes per <http://www.heatpipe.com/heatpipes.htm> which are described as cylinders not pipes per se. A Heat pipeline is a theoretical construct which may or not be viable as a practical matter even though possible in theory. The two ideas are first cousins not brothers and sisters. Perhaps two main topics? Or at least two sub topics!

See wikipedia:Heat pipe. This article is about the heat pipeline design project, not about heat pipes, although collecting information about heat pipes into Heat pipe would be a noble endeavor. By the way, I'm looking at http://www.apropedia.org/, which has many users (I suspect they might be wikipedians who want to write things not accepted under original research policy of wikipedia). That might be a better place for general information about heat pipes. Archimerged 00:45, 6 July 2006 (UTC)

A proposal for a 'patented' system consisting of a pipeline to bring air from a mountain top down to a valley via a large pipeline. At the bottom end a section of line was shaped to speed up the velocity to run a turbine and produce power. Seemed to be theoretically possible but was not economically feasible.

A patent merely protects the interests of the patent holder for a specific period of time. It does not warrant the usability of the patented item. User:NotSCar 13:35, 5 July 2006 (UTC)

Cold air is much less dense than liquid propane. The heat pipeline with turbine in the liquid return might be much more viable.

BTW Archimerged is very down on the "intellectual property system" which is neither intellectual nor property nor a system... See Moglen's January 1995 speech, http://emoglen.law.columbia.edu/my_pubs/nospeech.html "The technical obstacles to the digital revolution in scholarship are small compared to the oppressive deadweight of the intellectual property system, a tripartite oxymoron like Voltaire's Holy Roman Empire." (Voltaire famously said it was "neither holy, nor Roman, nor an empire").

NotSCar, What do you have in the nickname field of Special:Preferences? Do you use ~~~~? A trailing square bracket is missing somewhere... Archimerged 00:45, 6 July 2006 (UTC)

A HeatPipe 185 long burried vertically in the earth is described at: http://www.wired.com/news/technology/0,1282,48947,00.html It is intended for the generation of electric power. NotSCar 14:01, 6 July 2006 (UTC)

[edit] Turbine in the return pipe

Density considerations lead to conclusion that using propane, the upward pipe need not be more than 100 times larger than the downward pipe. Maybe a lot less would work.

Insulating the liquid filled return pipe is extremely important, or else the liquid could start boiling and lead to a blowout. Insulating the upward pipes is perhaps less important (if you aren't primarily concerned with running a heat engine at the top of the mountain): the consequence of heat flowing out of the vapor line is condensation and liquid running down the vapor line without doing any work. Less expensive insulation could be used.