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I live in Louisiana these days, in an area that is known for its numerous antebellum plantation homes (circa early 1800s). While touring one of these homes it was clear that almost everything about the house was designed around keeping cool in the summer. Some examples:

  • 4-meter-high ceilings to allow hot air to rise to the ceiling.
  • Floor-to-ceiling windows to allow hot air at the top to escape and cool air to be drawn in at the bottom.
  • Porches on the sunny sides of the house to prevent sunlight from entering the windows.
  • Large central staircases to allow hot air to rise to the second floor, drawing cool air in on the bottom floor.
  • Some have a cupola, a central observation room at the top of the house, again to allow hot air to escape at the top of the house and draw air in from the bottom.

My question is: Given our modern understanding of thermodynamics, how could one design a home today to be cooled passively? Could we do any better than the plantation owners of the 1800s?

Let's define cooling as making the house more comfortable for humans. This means that it is not only important to reduce the temperature, but also to block sunlight and maintain airflow. Also, if possible, it would be very beneficial to extract moisture from the air.

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In dry/arid areas a wind catcher tower in conjunction with a qanat is a great way to keep buildings cool. The underground water stays cool and cools the air passing over it that is drawn in through the wind catcher.

However, in a humid climate you would want to isolate the incoming warm/moist air from the cool underground water. You could pass pipes through a large underground water tank and draw the air through those, this may also condense some of the moisture out of the air and you'd need drainage outlets from the air-pipe that come outside of the water tank.

Passive house cooling system

Obviously you'd use a much better heat exchange method than I drew in this rather crude picture, but hopefully it explains the basic idea.

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  • $\begingroup$ A nice idea, but I was wondering how much water would be required to be effective for a 20,000 cu ft house. In other words, how big does the heat sink need to be and how good is the thermal conductivity between the water and the earth. It would seem the water would warm rather quickly. $\endgroup$
    – user5108_Dan
    Commented Jul 20, 2015 at 13:17

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