Saturday 25 June 2011

Low Cost Room Cooling

All over the world, cities are becoming more and more congested with people living out of rectangular boxes that are called flats. There is no proper ventilation and the only cooling option available is installing an air conditioner. However air conditioners consume huge amounts of power making it in-affordable to the masses. A bigger problem with ACs is that they generate huge amounts of heat that is dissipated outside the buildings or rooms into the surrounding atmosphere causing an increase in the overall temperature in the vicinity. Ceiling fans provide air circulation but they circulate the same hot air over and over again. As hot air rises towards the ceiling, it is pushed down by the fan and the cycle gets repeated.

Now if the cycle of air circulation was reversed and the top half of the room was designed to cool the air, then hot air from the room gets pushed upwards, gets cooled and cold air falls to the ground, creating a cooling air current. To achieve this, the top half of the room's walls as well as the ceiling can be covered with a special material that is porous and lined with capillaries. Water is supplied into this material in a regulated manner to let it remain constantly moist. The ceiling fan's blades are designed to push the air up instead of down. The hot air from the room is now pushed upwards into the moist ceiling and wall panels and this causes a cooling effect due to evaporation. The cooler heavier air now moves downwards from the sides and provides an overall cooling comfort to the people in the room. For a better heat transfer, the cooling panels can be designed to have three dimensional extrusions to add more moist surface area and provide some resistance to trap the air as it flows over those surfaces. By covering the top half walls and ceiling with moist panels, we get a fairly large surface area for heat exchange. The water supply to the panels can be from the regular domestic pipes with special regulators to provide only a trickle flow that is just enough to keep the panels moist. Water from the wash basins and baths that generally flows down the drains, can also be filtered, cleaned and recycled to be used in these panels.

Similar moist panels placed on the outer walls of a building or bungalow and on the roof, can also help in reducing the overall temperature of the building. Automobiles fitted with these panels on the outside over the existing body will also run cooler than those with conventional metal surfaces that fully absorb the sun's heat.

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