Tuesday, March 6, 2018

Cooling cities and enhancing convectional rain

Method to cool hot cities, decrease air pollution and bring convectional rain. How does a city get hot? Well the sun shines on outside walls of buildings and the walls heat up and radiate heat to all objects around. How could you stop this? If you place greenhouse plastic, on the outside of buildings, a few centimetres away from the walls, then the sun shines (with high frequency radiation from the hot sun) through the greenhouse plastic onto the walls which heat up. Now the low frequency infrared radiation from the hotter walls (cooler than the sun) cannot get out through the greenhouse plastic and so will not heat up people and other objects around the walls. Instead the air is heated up between walls and greenhouse plastic and convection causes it to rise. The walls thus become air-cooled and the heat is transferred to the air. The rising air will draw in cleaner air from the air surrounding the city, the chances of convectional rain will be increased (more than just from having the urban heat island effect) and the city could become cooler because of:
1) Virtually no infrared radiation from hot walls of buildings onto objects. There will be some radiation from the greenhouse sheeting, but sun shines through greenhouse sheeting without heating it much at all.
2) Air cooling
There will also be possible cooling from:
1) Cloud formation that will shade the city
2) Rain which cools.

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