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Nick,<div>Your detailed contributions are hampered by the, um.. demanding font in which they appear.</div><div>Is it possible to zoom it a notch for readability?<br><div> <span class="Apple-style-span" style="border-collapse: separate; color: rgb(0, 0, 0); font-family: Helvetica; font-size: 12px; font-style: normal; font-variant: normal; font-weight: normal; letter-spacing: normal; line-height: normal; orphans: 2; text-align: auto; text-indent: 0px; text-transform: none; white-space: normal; widows: 2; word-spacing: 0px; -webkit-border-horizontal-spacing: 0px; -webkit-border-vertical-spacing: 0px; -webkit-text-decorations-in-effect: none; -webkit-text-size-adjust: auto; -webkit-text-stroke-width: 0; "><span class="Apple-style-span" style="border-collapse: separate; color: rgb(0, 0, 0); font-family: Helvetica; font-size: 12px; font-style: normal; font-variant: normal; font-weight: normal; letter-spacing: normal; line-height: normal; orphans: 2; text-indent: 0px; text-transform: none; white-space: normal; widows: 2; word-spacing: 0px; -webkit-border-horizontal-spacing: 0px; -webkit-border-vertical-spacing: 0px; -webkit-text-decorations-in-effect: none; -webkit-text-size-adjust: auto; -webkit-text-stroke-width: 0px; "><span class="Apple-style-span" style="border-collapse: separate; color: rgb(0, 0, 0); font-family: Helvetica; font-size: 12px; font-style: normal; font-variant: normal; font-weight: normal; letter-spacing: normal; line-height: normal; orphans: 2; text-indent: 0px; text-transform: none; white-space: normal; widows: 2; word-spacing: 0px; -webkit-border-horizontal-spacing: 0px; -webkit-border-vertical-spacing: 0px; -webkit-text-decorations-in-effect: none; -webkit-text-size-adjust: auto; -webkit-text-stroke-width: 0px; "><div>Clarke Olsen</div><div>373 route 203</div><div>Spencertown, NY 12165 </div><div>USA</div><div>518-392-4640</div><div><a href="mailto:colsen@fairpoint.net">colsen@fairpoint.net</a></div><div><br></div></span><br class="Apple-interchange-newline"></span><br class="Apple-interchange-newline"></span> </div><br><div><div>On Jan 11, 2011, at 4:04 PM, nick pine wrote:</div><br class="Apple-interchange-newline"><blockquote type="cite"> <div><strong><font size="2" face="Courier New">RT <</font></strong><a href="mailto:ArchiLogic@yahoo.ca"><strong><font size="2" face="Courier New">ArchiLogic@yahoo.ca</font></strong></a><strong><font size="2" face="Courier New">> writes:</font></strong></div><strong><font size="2" face="Courier New"></font></strong><strong><font size="2" face="Courier New"></font></strong><strong><font size="2" face="Courier New"></font></strong><strong><font size="2" face="Courier New"></font></strong><strong><font size="2" face="Courier New"></font></strong><strong><font size="2" face="Courier New"></font></strong><strong><font size="2" face="Courier New"></font></strong> <div><br><strong><font size="2" face="Courier New">> Once a house is well insulated/air-sealed and its massing, orientation and <br>> landscaping have been reasonably well considered, the building heat load <br>> will be so minimal that occupancy gains and solar gains should provide <br>> most of it (speaking "typical"-sized houses, say 1600 - 2800 sf) in Cold <br>> Climate Regions, say, > 7500 HDD/yr)</font></strong></div> <div><strong><font size="2" face="Courier New"></font></strong> </div> <div><strong><font size="2" face="Courier New">Bullshit.</font></strong></div> <div><strong><font size="2" face="Courier New"></font></strong> </div> <div><strong><font size="2" face="Courier New">Then again, Sustainable Building Industry Council ma</font></strong><strong><font size="2" face="Courier New">sonry </font></strong><strong><font size="2" face="Courier New">salesmen </font></strong><strong><font size="2" face="Courier New">say</font></strong></div> <div><strong><font size="2" face="Courier New">reasonably well considered lukewarm sunspaces </font></strong><strong><font size="2" face="Courier New">with </font></strong><strong><font size="2" face="Courier New">LOTS of </font></strong><strong><font size="2" face="Courier New">thermal mass</font></strong></div> <div><strong><font size="2" face="Courier New">(</font></strong><strong><font size="2" face="Courier New">bricks, </font></strong><strong><font size="2" face="Courier New">according to SBIC</font></strong><strong><font size="2" face="Courier New"> Brick Institute </font></strong><strong><font size="2" face="Courier New">of America </font></strong><strong><font size="2" face="Courier New">members :-) can </font></strong><strong><font size="2" face="Courier New">give</font></strong></div> <div><strong><font size="2" face="Courier New">a max 60% </font></strong><strong><font size="2" face="Courier New">solar heating </font></strong><strong><font size="2" face="Courier New">fraction, even here </font></strong><strong><font size="2" face="Courier New">in PA, </font></strong><strong><font size="2" face="Courier New">with a mere 4954 FHDD.</font></strong> </div> <div><strong><font size="2" face="Courier New"></font></strong> </div> <div><strong><font size="2" face="Courier New">Then again, "most" can leave a lot. If a department store sells </font></strong><strong><font size="2" face="Courier New">a $1000 </font></strong><strong><font size="2" face="Courier New">shirt</font></strong></div> <div><strong><font size="2" face="Courier New">with a 60% discount, it's still </font></strong><strong><font size="2" face="Courier New">a $400 shirt. Direct </font></strong><strong><font size="2" face="Courier New">gain </font></strong><strong><font size="2" face="Courier New">houses </font></strong><strong><font size="2" face="Courier New">with minimal</font></strong></div> <div><strong><font size="2" face="Courier New">fuel bills in cold climates cost a lot, because windows </font></strong><strong><font size="2" face="Courier New">on living </font></strong><strong><font size="2" face="Courier New">spaces lose</font></strong></div> <div><strong><font size="2" face="Courier New">heat on cloudy days. It's better to focus on absolute </font></strong><strong><font size="2" face="Courier New">fuel consumption than</font></strong></div> <div><strong><font size="2" face="Courier New">fractional </font></strong><strong><font size="2" face="Courier New">savings.</font></strong></div> <div><strong><font size="2" face="Courier New"></font></strong> </div> <div><strong><font size="2" face="Courier New">If cloudy days are like coin flips (a reasonable assumption, according to my</font></strong></div> <div><strong><font size="2" face="Courier New">TMY2 simulations) </font></strong><strong><font size="2" face="Courier New">a house that can keep itself warm for </font></strong><strong><font size="2" face="Courier New">N </font></strong><strong><font size="2" face="Courier New">cloudy </font></strong><strong><font size="2" face="Courier New">days in a row</font></strong></div> <div><strong><font size="2" face="Courier New">has a 1-2^-N solar heating fraction, eg 50% for 1 day, </font></strong><strong><font size="2" face="Courier New">75% for 2, </font></strong><strong><font size="2" face="Courier New">and so on... </font></strong></div> <div><strong><font size="2" face="Courier New">90% requires -ln(1-0.9)/ln(2) = 3.3 days, 95% </font></strong><strong><font size="2" face="Courier New">requires </font></strong><strong><font size="2" face="Courier New">4.3...</font></strong></div> <div><strong><font size="2" face="Courier New"></font></strong> </div> <div><strong><font size="2" face="Courier New">A direct gain house in Minneapolis (7981 FHDD) in December will cool from</font></strong></div> <div><strong><font size="2" face="Courier New">70 to 60 F in </font></strong><strong><font size="2" face="Courier New">-RCln((60-17.9)/(70-17.9)) </font></strong><strong><font size="2" face="Courier New">= 0.213RC cloudy hours, wh</font></strong><strong><font size="2" face="Courier New">ere </font></strong><strong><font size="2" face="Courier New">RC</font></strong></div> <div><strong><font size="2" face="Courier New">is the house time </font></strong><strong><font size="2" face="Courier New">constant in hours, so a 95% solar fraction requires </font></strong><strong><font size="2" face="Courier New">RC</font></strong></div> <div><strong><font size="2" face="Courier New">= 4.3x24h/0.213 </font></strong><strong><font size="2" face="Courier New">= 484 </font></strong><strong><font size="2" face="Courier New">hours = C/G, where C is the house thermal mass </font></strong><strong><font size="2" face="Courier New">in</font></strong></div> <div><strong><font size="2" face="Courier New">Btu/F and G is </font></strong><strong><font size="2" face="Courier New">the house </font></strong><strong><font size="2" face="Courier New">conductance in Btu/h-F (with nicely cancelling</font></strong></div> <div><strong><font size="2" face="Courier New">units: C/G = (Btu/F)/(Btu/h-F) = h.) </font></strong></div> <div><strong><font size="2" face="Courier New"> </font></strong> </div> <div><strong><font size="2" face="Courier New">A 40'x60' house fully-loaded with room temperature thermal mass might </font></strong><strong><font size="2" face="Courier New">have</font></strong></div> <div><strong><font size="2" face="Courier New">a 6" </font></strong><strong><font size="2" face="Courier New">floorslab with 6"/12"x40x60x25 = 30K Btu/F plus 2(40+60)x8x5 = 8K Btu/F</font></strong></div> <div><strong><font size="2" face="Courier New">hollow concrete block walls, with C = 38K Btu/F and G = C/484 = 78 Btu/h-F.</font></strong></div> <div><strong><font size="2" face="Courier New"></font></strong> </div> <div><strong><font size="2" face="Courier New">With A ft^2 of U0.25 south </font></strong><strong><font size="2" face="Courier New">windows with 50% solar transmission (a low U-value</font></strong></div> <div><strong><font size="2" face="Courier New">to maximize cloudy </font></strong><strong><font size="2" face="Courier New">day heat storage) </font></strong><strong><font size="2" face="Courier New">and </font></strong><strong><font size="2" face="Courier New">820 Btu/ft^2 of sun on the south wall,</font></strong></div> <div><strong><font size="2" face="Courier New">24h(70-17.9)(0.25A+Gmax) = 410A makes A = 12.8Gmax, where Gmax only includes</font></strong></div> <div><strong><font size="2" face="Courier New">the ceiling and wall and ventilation conductances and 0.25A+Gmax < 78, which</font></strong></div> <div><strong><font size="2" face="Courier New">makes Gmax < 5.7 Btu/h-F, with A = 72 ft^2 of south windows.</font></strong><strong><font size="2" face="Courier New"> <strong><font size="2" face="Courier New">In a perfectly </font></strong></font></strong></div> <div><strong><font size="2" face="Courier New"><strong><font size="2" face="Courier New">airtight </font></strong></font></strong><strong><font size="2" face="Courier New"><strong><font size="2" face="Courier New">house, </font></strong></font></strong><strong><font size="2" face="Courier New"><strong><font size="2" face="Courier New">a 30 cfm 90% ERV adds about </font></strong></font></strong><strong><font size="2" face="Courier New"><strong><font size="2" face="Courier New">0.1x30 = 3 to </font></strong><strong><font size="2" face="Courier New">Gmax, </font></strong><strong><font size="2" face="Courier New">leaving 2.7</font></strong></font></strong></div> <div><strong><font size="2" face="Courier New"><strong><font size="2" face="Courier New">for walls </font></strong></font></strong><strong><font size="2" face="Courier New"><strong><font size="2" face="Courier New">and ceiling, eg 5928 ft^2 of 5928/2.7 = R2196 walls and ceiling,</font></strong></font></strong></div> <div><strong><font size="2" face="Courier New"><strong><font size="2" face="Courier New">eg R5/inch </font></strong></font></strong><strong><font size="2" face="Courier New"><strong><font size="2" face="Courier New">Styrofoam walls and ceiling, 36.6 feet thick :-)</font></strong></font></strong></div> <div><strong><font size="2" face="Courier New"><strong><font size="2" face="Courier New"></font></strong></font></strong> </div> <div><strong><font size="2" face="Courier New">> the remaining auxiliary heating requirement will be so small that</font></strong></div> <div><strong><font size="2" face="Courier New">> a wee woodstove is quite adequate as the auxiliary heat source.</font></strong></div><strong><font size="2" face="Courier New"> <div> </div> <div>After a few cloudy days, the wee woodstove needs to supply all the house heat.</div> <div>How much wood do you have to feed it over a 7981 FHDD Minniapolis winter, if</div> <div>the house walls are less than 36 feet thick? :-)</div> <div><br>> True, one could probably get close to 100% of the building's heat load <br>> from occupancy/solar gains by making the house look like one of Nick <br>> Pine's wet dreams, but curiously enough, most people seem to like having <br>> windows on their homes and have their houses look like houses rather than <br>> Grade 6 science experiments gone awry.</div> <div> </div> <div>It's fun to live in science experiments gone awry :-)</div> <div> </div> <div>Nick</div></font></strong><div style="margin-top: 0px; margin-right: 0px; margin-bottom: 0px; margin-left: 0px; ">_______________________________________________</div><div style="margin-top: 0px; margin-right: 0px; margin-bottom: 0px; margin-left: 0px; ">Greenbuilding mailing list</div><div style="margin-top: 0px; margin-right: 0px; margin-bottom: 0px; margin-left: 0px; ">to Send a Message to the list, use the email address</div><div style="margin-top: 0px; margin-right: 0px; margin-bottom: 0px; margin-left: 0px; "><a href="mailto:Greenbuilding@bioenergylists.org">Greenbuilding@bioenergylists.org</a></div><div style="margin-top: 0px; margin-right: 0px; margin-bottom: 0px; margin-left: 0px; min-height: 14px; "><br></div><div style="margin-top: 0px; margin-right: 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