Passive cooled house in the tropics
 

A very interesting design that incorporates not only a double roof, but also double walls to allow airflow between the surface absorbing the suns radiated heat. Sounds pretty smart to me!

Build-It-Solar Blog: A Unique, Passively Cooled Home in the Tropics

Kotaro Nishiki - Passive Solar House in Tropical Areas, Rain Harvesting System, and Great Ideas


http://ecorenovator.org/forum/attach...1&d=1382123440

http://ecorenovator.org/forum/attach...1&d=1382123440

http://ecorenovator.org/forum/attach...1&d=1382123482

That is a very interesting (and smart) concept. I don't really see that working like somewhere in Wisconsin, unless the air was trapped in between the double wall and double roof. Here in California, I would need an operable opening, either manual or automatic, to trap the air or let it flow, depending on the season.

:thumbup:

Haha, I think it would work in Wisconsin, but really isn't necessary in this climate. Just make sure your overhangs are good and you're in pretty decent shape here.

Would a closed double wall not help keep the house warm during winters? I would think it would help alleviate some heater on time.

Oh definitely. A family friend has this kind of setup in their house in Wisconsin. He added a ~6ft wide I guess you'd call it a hallway on the south side of his house. It has a bunch of windows in it, and the 'inner' wall also has windows to get natural light. Expensive, but efficient and pretty cool even.

I agree with the concepts. The ventilation will remove much of the solar energy hitting the roof and east/west walls. But not all, so some btu will move from the double wall cavity into the house. Thermal mass of the interior may be enough to absorb these btus and maintain the interior at a temperature below daytime ambient. Especially if the inner wall is insulated.

I'd add an additional feature in climates with moderate humidity - misters. Water mist injected into the double wall cavity will remove btus without adding to the interior humidity.

Trees and vines are other techniques for providing shade and a limited amount of evaporative cooling.

Good ideas Jonr. And, welcome to the site!

I have a book I bought several years ago on a similar subject. Basically you were building a house inside a house (both insulated, both with windows). The basement was used as a heating/cooling source, the south side was a greenhouse, and the house it's self was normally quite small giving air an opportunity to flow up the greenhouse, over the interior house, into the basement, exchange some thermal energy, and back into the greenhouse. When it is cold out, the cycle is reversed. The idea was that you could normally use the greenhouse as a part of the house. They found that in order to have enough heating in the winters they needed a lot of glass on the greenhouse, and in order to not roast in the summer they needed a lot of ventilation (top, sides, the more the merrier). Lots of the homes built (decades ago) use supplemental thermal mass in the basement in the form of stacked brick/cinder blocks, gallon jugs of water, or something else. I'll see if I can find that book and report back with the name.

I made a 3rd grade-level drawing to illustrate the principals. The vent could be opened or closed according to temps in the greenhouse and/or house. Normally large doors were installed on the greenhouse to give ventilation from the bottom, and were propped open all summer.

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Daox,
Thanks for the post. I think this is a topic that does not get enough air play.
I tried to post a link to some pertinent info but I can't cause I am a newbe.
I suggest you google:
https://www.thenaturalhome.com/passivesolar.html
The double wall is a good idea for circulation but you need an insulation layer between the outside environment and the structure itself.
Here is a great example of how this idea works:
BIOMIMETIC ARCHITECTURE: Green Building in Zimbabwe Modeled After Termite Mounds | Inhabitat - Sustainable Design Innovation, Eco Architecture, Green Building
It is a great lesson on thermal mass and ventilation for natural living.
Those termites are awfully damn smart!
The thermal mass of the structure allows for the storage and transfer of energy (heat/cold) when the outside is not an ideal temperature whether that difference is hot or cold.
Here is a slightly upscale design I am working on for Jamaica employing these ideas:
http://greenearthstructures.com/1553vedaville.pdf
Here is one that is designed with rising water as a potential issue:
http://greenearthstructures.com/1612raised.pdf
I am thinking more and more that the idea of a basement rather than slab on grade is a good idea and might re-design the vedaville model to include this.
These designs are engineered to withstand regional earthquake and hurricane loads.
Both models incorporate rainwater harvesting.
The materials used are (pretty much) readily available anywhere.
Here is a design for a 4 season greenhouse I am working on using the same principals:
http://greenearthstructures.com/hatfieldgrnhouse.pdf
If I were to build in northern climes I would add a sunspace as Wyatt suggests. Adding radiant heat to the space as I moved farther north. As Jonr suggests humidification is a good option in dry climates.
The idea also works quite well for a re-model. Simply put an insulation layer of whatever works in your area on the outside and WaLa you have a super efficient remodel.