From http://www.sciencedirect.com/science/article/pii/S1364032113008460 http://www.sciencedirect.com/science/article/pii/S1364032113... 6.4. Super chimney The s

From http://www.sciencedirect.com/science/article/pii/S1364032113008460 http://www.sciencedirect.com/science/article/pii/S1364032113... 6.4. Super chimney The super-chimney imagined by Pesochinsky [150,154] consists in a huge vertical open duct at both ends, which works as a giant vacuum cleaner, transferring hot air from the sea level to the atmosphere 5 km higher, where temperature is 30 1C. The principle consists in the chimney effect based on the fact that hot air rises by buoyancy above cold air, because hot air is less dense and therefore lighter than cold air. But the process can be made more intense preventing the mixing of warm and cool air, so a chimney prevents inside air from mixing with the outside air until the air exits. The chimney stack effect needs a differential of temperature between the air inside and outside to run correctly. Moreover, the higher the chimney is, the more efficient it is. It is a similar concept to previously described SCPP [148], except that there is no solar collector at the bottom of the tower, which usually couples the GH effect to the sucking effect of the chimney. According to Pesochinsky the temperature difference between the bottom and the top of the tower is sufficient. Another difference with conventional SCPPs concerns the size, 5–10 times bigger: up to 10 km high with a diameter of up to 1 km. Even if these heights have never been reached by human buildings, some GE / CE projects reported in the initial part of this review envisioned similar heights [59–65]. Furthermore, some authors reported, with such a large duct and in certain atmospheric conditions, that a cold air inflow could occur at the top and as a result a layer of cold air could get out at the bottom of the chimney, the hotter air surface being just pushed up, with the creation of a thermal inversion. In terms of heat transfer the result is nearly the same: cold air down and hoIndeed, on some Pesochinskys designs, the tower is alongside a mountain slope or drilled inside a mountain (which seems too expensive) and numerous air pipes are connected on the sides. Di Bella [155] suggested a similar concept by using giant open pit-mines and also recycling waste-heat from power plants. This heat input could be useful to prevent cold inflow entering these large diameter chimneys. To illustrate the potential of these devices, according to Pesochinskys calculations [156] only 10 super chim-neys 5 km high can offset the heat surplus in the Earth atmo- sphere, which causes current global warming. This would mean that all the atmospheric circulation would be completely reorga-nized from only 10 points on the Earth’s surface: the climate induced perturbations could be much worse than what we want toavoid. Hopefully with smaller, cheaper and more numerous superchimneys, better distributed on the surface of the planet, thisdeleterious effect can be avoided. The calculations done are rather simple, and were confirmed by Mudde [157] from Delft Universityof Technology. They are based on a difference of temperature of 50 1C and as the super-chimney will facilitate air convection bybringing masses of warm air up to 5 km, then when the heat from the air radiates out, as it will be already at high altitude, lessenergy will be reabsorbed by the atmosphere, due to a thinner layer of atmosphere to go through. Therefore, more heat will beleaving the atmosphere, thus reducing the global atmospherictemperature. The authors believe that more scientific studies areneeded to prove the concept, and that the techology still fairly mature to build 5 km high chimneys.Constructional generalities are given by Pesochinsky with no real details: tall skyscrapers already exist; unlike chimneys, build-ings entail much heavier construction because there are floors, ceilings, several fluids and lifts going up and down, and all otherelements within buildings which are necessary to make it useful for humans. A chimney is just a cylinder, thus is a much lighterstructure and can be build a lot taller than any building with new “super-strong”materials, not even described by Pesochinsky