<div dir="ltr"><div style="font-family:arial,sans-serif;font-size:12.666666984558105px">Don't know the details of it's construction. But it looks like a nice space.</div><a href="http://www.offgridworld.com/ugly-duckling-shipping-container-home-built-by-artist-is-a-beautiful-swan-on-the-inside/" target="_blank" style="font-family:arial,sans-serif;font-size:12.666666984558105px">http://www.offgridworld.com/ugly-duckling-shipping-container-home-built-by-artist-is-a-beautiful-swan-on-the-inside/</a><br>
<div class="gmail_extra"><br><br><div class="gmail_quote">On Tue, Nov 19, 2013 at 7:26 AM, nick pine <span dir="ltr"><<a href="mailto:nick@early.com" target="_blank">nick@early.com</a>></span> wrote:<br><blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex">
Sean Rauch wrote:<br>
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-We live in Manitoba Canada and plan to build just outside of Winnipeg<br>
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<a href="http://rredc.nrel.gov/solar/calculators/PVWATTS/version1/International/pvwattsv1_intl.cgi" target="_blank">http://rredc.nrel.gov/solar/<u></u>calculators/PVWATTS/version1/<u></u>International/pvwattsv1_intl.<u></u>cgi</a> says 3.13 kWh/m^2 (992 Btu/ft^2) of sun falls on a south wall on an average December day in Winnipeg.<br>
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The stat file at <a href="http://apps1.eere.energy.gov/buildings/energyplus/cfm/weather_data3.cfm/region=4_north_and_central_america_wmo_region_4/country=3_canada/cname=CANADA" target="_blank">http://apps1.eere.energy.gov/<u></u>buildings/energyplus/cfm/<u></u>weather_data3.cfm/region=4_<u></u>north_and_central_america_wmo_<u></u>region_4/country=3_canada/<u></u>cname=CANADA</a> says the average December temp is -14.1 C (6.6 F) with a -12.1 high.<br>
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-I'm working with a model right now that has 2000 square feet of living space spread out over two floors<br>
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... eg 32'x32'x16'-tall, with a 1024 ft^2 ceiling and 2048 ft^2 of walls.<br>
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-We're planning the basic south facing windows with thermal mass inside to collect as much winter sun as possible.<br>
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That could work. If the house has no internal heat gains and it's 75 F on an average day and 65 after 5 cloudy days in a row (with a 2^-5 probability), 65 = 6.6 + (75-6.6)e^(-5x24/RC) makes time constant RC = 759 hours. With US R30 walls and an R60 ceiling and R30 night- and cloudy-day window insulation and a 1/R = G = 1024/60+2048/30 = 85 Btu/h-F cloudy-day conductance, it would need C = 759hx85Btu/h-F = 64.8K Btu/F of room temp thermal mass, eg 64.8K/25 = 2591 ft^3 of concrete or 4048 ft^3 of cylindrical rock gabions, about 25% of the house volume, or more, with less night window insulation.<br>
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-The house wont be off grid but I don't want to rely on the grid for any of the climate control demands of the house.<br>
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It might have a shiny massy ceiling heated by passive air heaters, with a thermostat and a slow low-power ceiling fan to mix down hot ceiling air as needed to keep the house exactly 70 F for 5 cloudy days, or 70 F during the day and 60 at night. Here's a nice air heater: <a href="http://www.builditsolar.com/Projects/SpaceHeating/solar_barn_project.htm" target="_blank">http://www.builditsolar.com/<u></u>Projects/SpaceHeating/solar_<u></u>barn_project.htm</a> With hot ceiling air and colder air outdoors, you might use R2 twinwall polycarbonate with 80% solar transmission instead of a single layer in balmy Montana. Gary Reysa and I tried this scheme in 2010, with one big mistake, an uninsulated partition wall that turned the air heater into an air cooler at night... <a href="http://www.builditsolar.com/Experimental/dCube/Barra/BaraBox.htm" target="_blank">http://www.builditsolar.com/<u></u>Experimental/dCube/Barra/<u></u>BaraBox.htm</a><br>
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With no windows (use flat screen TVs and outdoor cameras), the house would need about (65-6.6)85 = 5K Btu/h or 119K Btu/day (collect 20K Btu/h for 6 hours) or 596K Btu for 5 cloudy days in a row. At (say) 160 F, a 1 ft^2 twinwall air heater would gain 0.8x992-6h(160-6.6)1ft^2/R2 = 460 Btu on an average day, so the house could have 119K/460 = 260 ft^2 of air heater glazing, eg an 8'x32' south wall. A 1024 ft^2 ceiling with a 3 Btu/h-F-ft^2 slow 2-sided airfilm conductance would be about 20KBtu/h/3KBtu/h-F = 7 F cooler than the hot air around it when collecting heat on an average day, and a 5.5"x32' air heater flow path with A = 14.7 ft^2 and H = 8' would make the air heater air (20K/(16.6x14.7sqrt(8)))^(2/3) = 9.4 F warmer than the air near the ceiling, so the ceiling would be 160-9.4-7 = 144 F on an average day.<br>
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A 1000 cfm ceiling fan could keep the house 70 F with a 70+5KBtu/h(1/3K+1/1K) = 77 F ceiling, and (144-77)C = 596K makes C = 4.3K Btu/F for 5 cloudy days in a row, ie 4.2 psf, eg 0.8 inches of water, or deeper water in trays that cover less ceiling surface.<br>
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Have fun :-)<br>
<br>
Nick <br>
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</blockquote></div><br><br clear="all"><div><br></div>-- <br><br><br>b e n j a m i n p r a t t<br> <br>professor art+design<br>the university of wisconsin stout
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