Friday, February 17, 2017

Cool Arctic with heat pipes

Heat pipes are used in the Arctic to keep the ground cold so that structures are secure. The heat pipe, used next to the structure, uses a fluid that is heated in winter by ground temperatures that are higher than the air temperatures. The fluid evaporates, moves up from the ground into the air zone and condenses into liquid, releasing the heat to the cold air. This liquid now moves downwards and the cycle starts again - see thermosyphons section at
Now part of the reason that there is little snowfall in the Arctic is that with thawing and evaporation in summer there is relatively a lot of moisture in the air, but the air is cold (so cannot hold much moisture) and does not rise far enough to cause snow to fall (it needs to be warm so it can rise and cool significantly so that a lot of water vapour condenses out). The thermosyphon warms the air and cools the ground, so there are two benefits. A solar air heater could be used above the thermosyphon so that cool air is drawn in from ground level to cool the top of the thermosyphon. This will dramatically increase the ability of the air to rise far and cause snowfall. Snowfall increases the albedo and so more cooling will occur.
If you put a 1 sq metre solar air heater above the thermosyphon on a clear day at noon on 1 July at the latitude shown on the graph, you can theoretically heat the number of cubic metres of air shown by 1 deg every second. This is for a "facing the sun" solar air heater. A horizontal solar air heater at these latitudes gets much less insolation. There are two important aspects at these latitudes: 1) the amount of air the sun shines through 2) the angle of the solar heater. Both these have been taken into consideration in the calculations.

No comments:

Post a Comment