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Jonathan_hodgkins's avatar

Using water as a construction material?

Asked by Jonathan_hodgkins (403 points ) November 7th, 2012

I need to design a sustainable house for a family of four in New England for my engineering design class. I was curious what the R value was of water. Would there be any benefit to building a wall out of glass / plastic that would be filled with water? wold it retain and insulate heat? Any other ideas about sustainable / green ideas?

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17 Answers

Judi's avatar

Solar thermal for water and heating, digging the dwelling into a mountain side for insulation, hay bail houses are supposed to be insulated well, hydro electric is the cheapest if you build your hydro by a year round stream, (since this is hypothetical anyway)

gorillapaws's avatar

Don’t forget about expanding/contracting of water when it freezes. Plus it would be difficult to run electrical, plumbing, hvac stuff in a house with water walls. Also if there ever was a leak, you’re looking at major mold issues which is very expensive to clean up, and also the possibility of electric shock with submerged wires.

On the plus side, your house would be pretty fireproof.

Jonathan_hodgkins's avatar

I was thinking about the south facing wall, not the entire house.

jrpowell's avatar

I would probably go with tire bales first.

RocketGuy's avatar

I went to a “green” house that had dozens of 1 gallon cans, filled with water and painted black, embedded in the S wall. The professor would open the outer wall during the day to allow the sun to warm the water. When he came home in the evening, he would close the outer wall and open the inner wall to let the water heat his living room. His heating bill in the winter was just over $30. (I live in the same city, but my heating bill averages >$200).

LuckyGuy's avatar

Water is great for storing heat energy. However, it is also a very good conductor of heat. Putting it between glass or plastic panels would be a bad idea. Your heat loss would be tremendous. Also consider the pressure the water will exert on the glass. Gas or vacuum filled windows are the best for good R values.

dabbler's avatar

@LuckyGuy is correct. Water is a good conductor of heat and can store heat well, but it is not a very good insulator at all.

However there is an architectural concept called the Trombe Wall that puts a high-heat-capacity mass (e.g. water), painted black, inside the living space so it will catch sunlight power and store it for later when it cools down in the night.

Seek's avatar

If you’re going for sustainable, two layers of 8-inch thick plexiglass that will be strong enough to hold a wall’s worth of water probably isn’t the most green-friendly way to go. I LOVE that paint can idea!

I hear recycled shredded blue jeans make great insulation. I am a big fan of repurposed wood floors – for example, paneling from old houses used as floorboards.

gasman's avatar

@dabbler Large containers of water, owing to their high thermal mass, help keep an interior space at constant temperature, once heated or cooled to the desired point, even without solar heating – purely passive.Thick concrete walls act similarly.

If water weren’t a good conductor of heat (very low R value) then water-cooled devices would overheat!

jerv's avatar

@LuckyGuy Figuring 62.5 lbs/ft^3, and stipulating a wall 10 feet high, I shudder to think what a “tank” thick enough to have a usable surface area/volume ratio would weigh. Without doing the math, I can already see the need for serious structural reinforcement.

rooeytoo's avatar

I recently watched a show where the house was partially constructed of rammed earth walls. It was a modern house and I loved the look of the walls when they were finished. They mix in some binding agents and when finished it was shiny and very textural. In the center of Australia many houses are built underground to keep them cool and warm too. Coober Pedy a large opal mining community is famous for them.

LuckyGuy's avatar

@jerv The pressure at the bottom of a 10 ft high window will exceed 4 psi and there a lot of square inches near the bottom! A one inch high strip, one foot long would need to resist 50 pounds. Now think of how many there are! That is why windows are filled with gas or vacuum..

Seek's avatar

@rooeytoo Oh! That reminds me of the Hobbit House! There’s a house down the road from my uncle’s place in Kentucky that’s built into the side of a hill. It’s always about 65–70 degrees (Fahrenheit) inside, and their power bill is just about nothing, even though they have to use almost 100% artificial light.

jerv's avatar

@LuckyGuy Maybe I’m just over-engineering, but I think one inch would absorb/dissipate heat too quickly to be useful; I was thinking no less than 4, and probably closer to 6. Multiply weight accordingly. And I used to have no end of fun opening/closing a watertight door with a pressure differential of <0.01 psi, so far more pressure over far more area….yeesh!

RocketGuy's avatar

That must be why the professor I visited used 1 gal containers – no significant water pressure on the bottom row of cans.

LuckyGuy's avatar

@jerv I used that as an example to show the force easily exceed a ton in no time. Not practical.

dabbler's avatar

Something like a wall of water or a trombe wall has to be considered a substantial architectural component of the structure and foundations built accordingly.
Otherwise you’ll suddenly one day have a swimming pool in the basement.

Take a look at the Zion National Park Visitors’ Center where they not only have provided support for the trombe wall but insulated it from the ground too.

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