Passive Cooling

Discussion in 'Homesteading Questions' started by Grandmotherbear, Apr 28, 2005.

  1. Grandmotherbear

    Grandmotherbear Well-Known Member Supporter

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    A few ? about passive cooling in a humid environment- swamp coolers WON'T work in Florida, the humidity is too high...

    As I drive around South Central Florida, I notice many older homes built with a second story room. (Sometimes 3rd story)! It is only the one room, it is usually very small- about 10 x 10 or smaller, and all 4 walls appear to be awniing crank windows.

    The smallest rooms are all "vents"- sorta like a wall of "Bahama blinds". This type has a much steeper pitched roof on it.

    Is this a passive cooling thing from the days before airconditioning? As this thought occurred to me I could see where opening such upper story windows would encourage air circulation by venting heated air- this would allow slightly cooler air to be drawn in the lower storey windows shaded by trees...and the upper stories wouldn't really need to be netted against bugs since most skeeters don't fly higher than 10- 12 feet

    I would appreciate if anyone has had any experience or knowledge to share about why there are these funny single-room "toppers" on the older homes.
    (Wish I had the ability to post a pic...)
     
  2. WanderingOak

    WanderingOak Well-Known Member

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    The 'cupola' rooms on the top of older houses are indeed for ventilation. I've seen many old houses which have air intakes in the basement, and a way for basement air to be pulled through the rest of the house. Warm air from the outside is pulled into the cool basement, and drawn through the entire house up to the cupola. Many older houses with these ventilation systems have been retrofit with whole house fans in the attic room. I'm not sure how well this would work in Florida though. I'm not sure how many houses have basements down there.
     

  3. bgak47

    bgak47 Well-Known Member

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    When I grew up in the south before air conditioning was common, many houses had attic fans. These were large fans mounted in the attic in the center of the house. They were designed to pull air in through the open windows & exhaust it through vents in the attic. That may be what you are seeing. It made sleeping bearable when it cooled off at night, but it really wasn't much use in high/temp high/humidity conditions. I can vividly remember when we got our first window-unit air conditioner in 1958. It was Heaven! Of course we all had to sleep in the living room untill we could afford more units. I still have window-unit air conditioners in my house because it was built before central air. My Great Aunt lived in a house that was built in 1901 that had an upstairs sleeping porch. It was screened & had 3 ceiling fans. I think I'll stick to air conditioning. ;)
     
  4. Grandmotherbear

    Grandmotherbear Well-Known Member Supporter

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    No basements in Florida. Water table too high. These are little rooms capped with a teensy or flat roof. It is hotter here now than in the past, since most green areas have been cut and paved over. Concrete absorbs heat and radiates it back all night...on average it is 9 degrees cooler under a large tree due to shade/transpiration.
     
  5. Cyngbaeld

    Cyngbaeld In Remembrance Supporter

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    http://www.phys.ufl.edu/~liz/hvac.html

    Here is a site you might find interesting.

    I think perhaps a cupola combined with earth tubes should really help cool and dehumidify a home that was properly set up for it. A few years ago I saw a house in a magazine that was built in the deep south with no A/c. It was up on stilts and had really high ceilings. Also had the tall windows that could be opened at the top to vent hot air and opened near the floot to admit cooler air. The house was set up near a wooded area to pull cooler air from under the trees.

    It was 1960 before we had our first a/c unit. I can remember the stores and theaters that advertised air conditioning to get customers on those hot summer days.

    It is also interesting how what seems a minor change can really affect passive cooling. When I was a child, my Granny Pearl's house was always cool downstairs and hot upstairs even with no a/c. Later mom had a garage installed on the west side. This blocked the breeze coming in the west door. From then on the downstairs was stuffy and hot.