Solar Cooling Tower, aka Solar Chimney

The solar cooling tower is a passive cooling technique which has been utilized for centuries to cool homes and other structures. A solar cooling tower is actually a sort of geothermal/solar power combination.

It consists of a long, wide, corrugated pipe laid into a trench about 5-10 feet below grade. This pipe, which will have drainage holes drilled into the bottom (on top of a gravel bed) to allow condensed water to run out, runs in a straight line away from the house. At the far end (away from the house) a 90-degree elbow shoots tube out of the ground, where a piece of mesh is mounted to keep critters out and a second elbow installed to protect against rain. Where it meets the house, a vertical section shoots up to the roof line and beyond. This is otherwise known as a convection or solar chimney.

Two intersecting sides of this tower are painted black and lined with metal to absorb solar heat. The other two sides are clear glass or plexiglass, acting as glazing to allow solar radiation to pass through. The black-painted sides need to face south in order to garner as much sunlight as possible. The cool air to run through the buried pipe should enter the house at a low point while the inside opening of the tower chimney should be at a high point inside the building.

The system works as follows: the sunlight warms the air in the chimney, creating an updraft, which pulls air out of the home. This will, at the other end of the system, draw air into the pipe that is buried underground. Temperature at this depth in the earth remains fairly constant year round. It subsequently cools the air as it passes through the pipe and into the home.

This simple cycle has been used since the ancient Romans to cool buildings. One more note, it is vital to have excellent insulation throughout the home, especially between the solar tower running up the exterior of the south-facing wall and the interior so that solar heated air cannot seep into the house.

Compressor Cooling / Swamp Cooling / Solar Misting System / Solar Cooling Tower