advice asked for smart ventilation without electricity

Discussion in 'Designing, building, making and powering your life' started by IngeLeonora, Feb 6, 2015.

  1. IngeLeonora

    IngeLeonora Junior Member

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    For the project I have in mind I need to know more on 'cooling'. I do not want to use electricity (airco, ventilators). I want to build (or rebuild, renovate) in such a way the tropical wind (most of the time coming from the same direction, north-eastern trade-winds) does the job!
    I have been taught (in the Netherlands) on ways to keep the heath inside the house, and I understand how I can keep the heath outdoors. But even then, some more cooling is needed, tourists visiting the place are not used to the tropical temperatures of Curaçao. (read: https://curaduracuracao.blogspot.nl/ ) 8)
     
  2. sweetpea

    sweetpea Junior Member

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    Hi, IngeLennora. I've seen use the concept of cool air near the ground being drawn up, as it's heated, through ventilation openings high on the wall between rooms. In the southern part of the US it's very hot and humid, and for generations they have used passive cooling principles in the architecture of buildings. Have you seen these?

    As long as the heat has a way out, it will draw the cool are in and up, as in this design:

    https://dnr.louisiana.gov/assets/TAD/education/ECEP/drafting/g/g.htm

    The earth is always 50 degrees F/10 C, and tapping into that from under the building brings up cool air in summer, warm air in winter. Although maybe your winters aren't that cold to bother with it.

    Cooling tubes will work, although be sure to put window screen over the intake tube so no insects or critters can get into it. You don't want mouse poop or dead mice in an air tube.

    https://www.simplesolarhomes.com/passive-cooling-and-heating-earth-tubes.html

    Although I think in a tropical climate I would be suspicious of these tubes because if moisture gets into them, and mold, it could send moldy air inside. Using an air filter might help, but that's one more maintenance thing that someone may not want. If the tubes are in the basement and it's dry under there, that might work a little better. But I would still use air filters and have a way to make sure those tubes don't get moldy.

    In all of these examples the heat has to have a way out up as high as possible, and there should be openings high on the walls between rooms to allow for the flow of air through the whole building. I can't find a photo of it right now, but in the late 1800s, early 1900s a lot of the houses in the south had about a 1/3 meter strip of open space (between the top of the wall and the ceiling, usually adorned with criss-cross lattice, along the length of the wall on the interior rooms, so heated air would rise and flow into the next room. I imagine you've seen that where you are.

    Lifting a building up on piers may be good for cool air in the summer, but it is not good for cold air and passive heating in the winter, for anyone in a nontropical climate. At least with the heating tubes you can control the input, and make sure that

    Do you mean "heat" when you say "heath"? I'm guess that's what you meant.
     
  3. sweetpea

    sweetpea Junior Member

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  4. IngeLeonora

    IngeLeonora Junior Member

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    Thank you very much, Sweetpea! I think this is information I can use. Because I do not (yet) live there (Curaçao), but in the cooler Netherlands, I still have to learn about methods for tropical climate. Many old methods are almost forgotten, because nowadays they use airco or ventilators. I saw openings in walls and I knew they were originally meant for cooling, but noone could tell me about it, how it worked.
    Sorry for my mistakes when I write in English. :(
     
  5. Brian Knight

    Brian Knight Junior Member

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    I think your english is as good as mine and its my primary language! I have modern opinions on this stuff so probably not what your looking for but.. The main reason people traveling to tropical climates feel uncomfortable is the humidity. Most of the natural cooling techniques dont address this issue like modern technology does. I would say build for natural ventilation and exclude unwanted heat gain but for ultimate comfort, use fans and heat pumps in an appropriate manner.

    Heres a blog on keeping comfortable in the summer, which is really aimed at more typical homes in our mixed climate. One of my favorite strategies there is nightime flushing, in which you open windows and interior doors at night and close everything up tight in the day. Iam not sure about the effectiveness of this strategy in a tropical climate where it doesnt get much cooler at night.

    Earthtubes is a strategy often talked about but I think its dangerous or troublesome in non-desert climates. Humid air will condense its moisture on the interior walls of the tubes which attracts pollen and dust resulting in mold and mildew. If you want to experiment with this strategy, be sure you pitch it to drain condensate and install a rope/wire with a heavy duty pig/plug to facilatate cleaning the walls of the tube. I dont think tropical ground temps offer too much of a desirable Delta T but could be wrong..

    My main advice for this climate would be to use lots of roof insulation if exposed to direct sunlight and try to design any windows to be shaded most of the day. Deep overhangs can help shade walls. Plant or use existing lanscape to help shade the house paying particular attention to the East and especially west. Low SHGC glass would be a good idea for windows that may get direct sunlight. Light colored roofing and siding is also a good idea.

    If youre planning on heating domestic water, use a heat pump water heater to get the "free" benefits of cooling with de-humidification. Using heat pumps powered with PV may be an overly techno-heavy approach to some but its tough to argue with its comfort and sustainability aspects.
     
  6. sweetpea

    sweetpea Junior Member

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    IngeLennore, that sounds exciting, quite an adventure! Are you going to be building a house, or you just want to work with an existing one? I imagine the folks in Curacao will be the most knowledgeable about how to keep the interior from being too humid and keeping cool.

    For what it's worth, not sure if you are buying or renting, but there are a lot of townhouses and condominiums these days that have many units where there are homeowner fees. The appeal is that everything is taken care of (supposedly) by these fees, maintenance of the units, insurance, pools, parking lots, a recreation area. The views from the upper balconies are often quite dramatic. These fees are forever and often go up. And if there isn't enough money accumulated to cover what's needed they can send out an extra bill to collect even more money. Sometimes, depending on how old the units are, the condominiums that are stacked on top of each other can have leaks, starting at the top (sometimes due to the homeowner, not necessarily any roof or deck issue) and leak all the way down through the lower units. Common walls are often not enough to block out loud noises from neighbors. The homeowner association minutes should be available to any potential buyer, and you should get at least 5 years worth of previous minutes to see what has been going on there as far as how well the finances are handled and if there are any structural issues, even if it involves just sidewalks, because the owners are responsible for all of the features of the whole place. A friend of mine had a townhouse in a small association of 15 unites where the person in charge stole all the money and left the country, leaving the homeowners to start from scratch, and it was a real disaster.

    I hope you'll let us know how it goes.
     
  7. IngeLeonora

    IngeLeonora Junior Member

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    Thank you for your reaction, Brian.
    Today I did some thinking on the subject. I won't even try tubes in the earth. This island has vulcanic rock underground (and partly fossilised corals). So digging deep is very difficult! And it isn't needed. The tropical 'trade winds' are blowing there (every day the wind blows, sometimes soft, sometimes hard, even stormy). So I need to use the wind to cool down the house. I combined the information Sweetpea gave with something I heard there from a lady living in an old mansion on the island. The 'less warm' air has to come from a sort of cellar or basement, under the house. From there it enters the living space (through openings in the floor). Because hot air goes up, there must be some openings in the top.

    There have to be 'shutters' too. Doors / windows without glass, but with wooden shutters to open and close. So air can flow through the shutters as much or as little as you want. When the sun shines you close the shutters on that side, so the heat of the sun won't enter. A 'veranda' (porch) prevents direct sunlight. There will be no windows with glass (what's the use of glass in a hot climate?). I think palm leaf roofs are very good isolation, as are cob walls.
    Opening the shutters at night to let the wind blow through has one problem: mosquitos! So mosquito nets are needed too.

    On the porch roof will be the solar panels, for electricity and for hot water.
    These are ome of my ideas.
     
  8. TLP

    TLP Junior Member

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    Prior to WW1 and the "Sick building syndrome" timber frame and straw-clay infill, lath and plaster, etc, hygroscopic mass envelopes that could store, regulated, release, heat, cold, moisture, was replaced with sticks and drywall introduced in 1940's that was originally over an inch thick with one inch holes drilled ~12" OC (a clear remnant that walls had to breath) now modern technology replaced with plastic barrier, sealing, and mechanically devices that are not need if you understand hygroscopicity...that take a book to explain, since it has been lost it's now an "unknown" especially to us westerners but not this and few other cowboy's :) George Swanson has a good book "Breathable Walls" if you really want to know how it works.

    I recently watched "Mankind" how we all evolved as a world on netflix. It talked about the Netherlands being the richest back in some year I forgot. Empires were torn down as fast as they were built...Good flick check it out.
     
  9. IngeLeonora

    IngeLeonora Junior Member

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    Sweetpea, sorry I did not reply on this.
    I can't answer all of it. First thing I am doing now is getting a 'project-group' together. Next week I'll be there (we'll be visiting friends and family at Curaçao, stay there for six weeks); some of the people I'll be visiting are already doing somthing like permaculture, green-building, a.a. Others may be interested in the art&culture part of my project.
    When there's a group, we can decide together how to go on. I think for this project the location is important: not too far from town and beach (and from the airport, where all tourists arrive), but also in nature, so you can have nice walks right from there. So we have to look out for a piece of land in that part of the island. If there's a house (ruin) on it, OK, we'll make use of that. If it's only a wild piece of land, then we can start building.

    What you tell about old houses with upper balconies ... could be in the part of town named Otrobanda. But I prefer to be further away from town center. Not only because of the needed land for a garden and the nearby nature for walks, but also because prices in town are much higher.
    Did you look at the information on the project here: https://curaduracuracao.blogspot.nl/ ?
    You can find a lot more information on Curaçao on the internet if you want.
     
  10. IngeLeonora

    IngeLeonora Junior Member

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    Hi TLP. I know there's a lot of information on how to build really good walls. Much of what I read already was about building in western Europe or northern America: 'getting heat in and keeping cold out'. For this project at the tropical island of Curaçao I need to know more on 'keeping heat out and cool air in'. Coming weeks, when I'll be at Curaçao again, I'll do my best to find the information that's still there on the traditional building methods of the island. There are still some old 'kunuku houses', where descendants of the African slaves lived, small houses they built themselves from local materials, with the kind of walls you describe (a frame, a woven structure and then a clay-like mixture over it). Someone I'm going to visit is busy restoring such a house.

    About the history of the Netherlands: do you know how this country became so rich in the 17th century? Colonies and slave trade mostly .... Curaçao was the place ships full of people stolen from Africa landed, the slaves were sold to America from there.
     
  11. S.O.P

    S.O.P Moderator

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