New possible clean Energy?

[Wallesteino]

I share with you this idea that came to my mind wandering on the world map years ago, and that I havn`t been able to challenge in the correct way as the people I interact with during my daily routine aren`t the most recommended to help me out.

 

Have anyone ever considered using the natural temperature gap that occurs in some part of the planet during the day-night transition?

 

what came to my mind at first was a system of "containers filled with a liquid that weight more during the temperature transition" connected through a pulley to a counterweight and an electricity generator connected to the pulley: when the temperature changes the container with the liquid will weight more and drop to the ground spinning the pulley and producing energy?

[swansont]

On a macroscopic level, things don't change weight when they are hot or cold.

[npts2020]

That temperature gap is what causes wind. There are many schemes for using wind to power something. Having said that, it is likely possible to use the temperature differences between say the Arctic and a tropical region but it would almost certainly be cost prohibitive because it would require some means of moving air on a global scale. Something like a wind tunnel could work but you are talking about building one a couple of thousand miles long (outrageously expensive) and not having a great deal of energy to extract when it is all said and done. There are probably other ways of doing such a thing but I can't imagine one that is going to give enough energy to make it worth the cost of construction when there are so many other ways of going about getting power.

[Enthalpy]

The day/night temperature swing has been studied in the hope to exploit its energy (...sorry, inventor's daily life) but it's seriously difficult.

 

First, it needs a huge heat storage, because you accept to waste perhaps 2K from 20K swing. This storage is much easier at a Solar thermal power plant, where heat is available at 800K for instance.

 

Second, heat from air isn't very concentrated, so you must move much air which costs energy. This is already a BIG difficulty for the heat dump of gas/petrol/coal/nuclear power plants; if no Ocean nor big river is available, only water evaporation achieves it at affordable volume and power. Now accept to waste 2K and evaporate no water, and the very difficult cooling tower gets completely impossible.

 

I'd make one more comparison. The temperature gradient in the Ocean is like 20K between the surface and -100m, similar to air swing. Water stores more heat per volume unit, and its temperature is available all the day. Though, nobody has made a breakthrough in this easier case. Some modest units exist (Hawaii), and their economics is rather to provide cold seawater for fish farms or make sweet water than energy.

Edited November 9, 2013 by Enthalpy

[EdEarl]

Have anyone ever considered using the natural temperature gap that occurs in some part of the planet during the day-night transition?

Temperature difference determines thermal efficiency, and 20C allows a small maximum efficiency of about seven percent, which means the amount of heat used is vast to power small things. Friction will further reduce efficiency. The low efficiency tends to increase the expense of machinery needed to capture and use the low temperatures and to generate mechanical power or electricity. See: https://en.wikipedia.org/wiki/Engine_efficiency#Mathematical_definition

 

Sources and sinks of heat that provide higher temperatures differences than 20C are preferred for power generation. The higher the temperature difference the better, but low enough not to melt an engine.