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Thread: Solar passive block house

  1. #11
    Senior Member zagam's Avatar
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    Solar passive house is heated during the day by sun in winter from properly shaded equator facing windows or cooled during the night by opening the windows. Passive solar buildings are passive and have no active heating or cooling.

    Concrete is bad as it has low thermal insulation or R value.

    In addition to R value you need thermal capacitance C.

    The product of these has the dimensions of time and is proportional to how long the building takes to respond to temperature changes.

    This thermal capacitance actually contains latent heat of air which is significant unlike "thermal mass" which is the small specific heat of solids which would result in a time constant too short to be useful. For R value to work the building must be sealed when windows are closed to prevent loss of this conditioned air.

    See my web site http://www.acima.asn.au/ for info on thermal insulation which provides the R part of this equation. See also http://www.cellulose.org/

  2. #12
    Senior Member zagam's Avatar
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    Window shading calculations for southern hemisphere

    My calcs http://www.acima.asn.au/solar.cgi with the required source code http://www.acima.asn.au/solar.ksh does solar calcs for southern hemisphere. Refs in the code do calcs for northern hemisphere.

    It important that sun dues not strike window when heating is not desired and important that it does when heating is desired.

    http://www.usc.edu/dept/architecture..._concepts.html

  3. #13
    Moderator jody's Avatar
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    I lived in two block houses. cold and damp.

    rammed earth is warm in winter cool in summer.

    I was looking at cob houses, and cordwood construction is really interesting.

  4. #14
    Moderator jody's Avatar
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    .......

  5. #15
    Moderator jody's Avatar
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    the center space is filled with sawdust for insulation.

  6. #16
    http://www.sips.org/

    seal your thermal envelope well.

    if you want to go green, try the already mentioned cordwood house. straw bail construction. if you want super crunchy look up "earthships"

    heating, pellet or wood stove. or cheat and just get a standard electric heatpump and buy green energy.
    c5/6 complete

    wait, what?

  7. #17
    Senior Member beecee's Avatar
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    you could also look into insulated concrete forms
    part of building green has to do with building with readily available material
    not trucking exotic materials to the jobsite

  8. #18
    Senior Member zagam's Avatar
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    There was a myth of thermal mass. In reality mass holds some heat and called heat capacity. However, its effect on the buildings response to temperature variation is too short to be useful.

    Cavity filled walls filled with insulation will work with latent heat within the building air.

    The only thing that stores heat better than air is water and phase change materials. Putting a water tank inside or under the floor could hold a lot of heat.

    You can move heat opening windows or retain it by closing them. You can use the air to store solar gain in winter.

    For those who can't operate shading and ventilation some thing like air-conditioning without the energy use could be used.

    I am not sure what you mean by blockhouse if its not a small, isolated fort in the form of a single building.

    You need to have winter sun unimpeded. You also need to be able to ventilate it when desired. In Mexican houses they have courtyard and patio for shade. They use courtyard for stack effect to change air. In a temperate climate you would angle the patio above the winter solstice to ensure full sun in winter.

    My company manufactures insulating blocks (for use in Australia), but we have still not killed the "thermal mass" myth. See Mud walls give poor insulation: CSIRO

  9. #19
    Thanks for all the replies, but when reality stuck we found we didn't have enough green to go green. We did purchase a house, still waiting for the closing. I didn't realize that it took so long, worried about having it ready before winter. Needs a lot of work.

  10. #20
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    Here in CA. R-value was given such a level of importance that title 24 efficiency compliance was mandated. However, they soon realized that the houses have become too tight in that they didn't breath enough and were having issues and have enacted a mandate for WHV (whole house ventilation) requirements were you are expected to have a dedicated fan, operating 24/7, drawing outside air into the conditioned space. Makes sense. Especially here in the Mojave Desert where ambient temps. are +110 in summertime. So, add +110 outside temp air to inside air conditioned space to make up an over-reliance on R-values which really are only important in wintertime while the heater is running. Here the winter lasts all of two months.

    For my location, an 18" thick rammed earth wall house would be a world of a difference to a 2 x 6 stick framed wall with an R-19 value. Passive heating/cooling doesn't mean zero heating or cooling systems. They are still installed but are only necessary to create the small difference in temps. to maintain a comfortable temp., over time enabling a greater savings in energy costs due to a smaller amount of energy used to make up this temp. difference.

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