Physics, Astronomy & Cosmology / Re: Could a town be cooled by pumping in cold air from hill country or the poles?« on: 06/02/2016 17:59:42 »
The problem with trying to cool by pumping cold air from a mountaintop into the valley is the reason why it is cold to begin with: its altitude. As the atmosphere circulates, air rises and falls. As it rises, it expands and cools; and falling, it heats. If you pump cold air from a high altitude to a lower altitude, the greater atmospheric pressure at the lower altitude will cause it to compress and heat, thereby nullifying the cooling. An alternative that might work is to transfer the temperature of the high altitude to a less-compressible medium and pump that instead. Thus, a heat exchanger on the mountain would cool water, which would then be pumped down into the valley. Undergoing very little compression, it would remain at essentially the same temperature. Then the cold water could be used to cool building, be pumped back up the mountain, discharge the heat up there, and so on. This would work, but the problem is to be able to do it at less cost than is required for other cooling methods. That might be easier said than done. If you want to keep pumping costs low, a large diameter pipe and capacious heat exchanger are needed so that little energy is lost due to viscosity. Also, the pipe needs to be well insulated, and the slower the water moves, the better the insulation must be. I don't know how the economics of all this would work out, but it is clear that a substantial infrastructure must be installed, the cost of which may make it infeasible.
Bravo! A near perfect response with solid physics.
Your engineering is sound, the idea doesn't come apart until economics are factored in.