Page 12 RAIN April 1979 The warm air which rises in central areas from heated mass would normally rise to the ceiling and then along the ceiling to stratify at thc top of the building. The down-draft from the windows falls across thc full width of the building, forming a momentum curtain which effectively blocks the normal passage of warm air from under the lower adjacent roof level. This blocking is made more effective by the next lower window seerion, which draws from the blocked warm air flow both to supply the down-draft and by pulling along some of the turbulent drag of the down-draft. Thus, each window section supports the draft action of each successive window section. The conflict of warm and cool drafts not only tends to distribute cooling action equally throughout and effectively resists the net upward flow of warm air but also diffuses the cold draft so that when standing directly under the windows no cold wind on the shoulders is felt . The back wall of the house is generally the warmest surface in the housc and because of its uninterrupted expanse forms a strong pull on the air mass, drawing large amounts of lower air upward vigorously supplying the down-draft on the first set of windows. It seems, fo r a variety of not altogether too conclusive reasons, that this is the action which tips the balance and causes a gentle net uphill flow of cookI' air. Th e total net effect, though much heat is lost by supplying the coldest surfaces with the warmest air, is a gentle feeling living space free of strong drafts and a tOp level to bottOm level nighttime temperature stratification of around five degrees, where I would have guessed there would be a fifteen- to twenty-degree difference. At night there is a pulsating aspect to this fluw as described in figures 8, 9 and 10. 1 know of no particular advantage this behavior results in except in helping makc sense of other observations and to give me the opportunity to describe clearly one of the morc extraordinary of the common behaviors I have observed. All sorts of air current patterns involve oscillating interactions composed of many transient flows. In general terms I find it intriguing to look for the rotating circle implied by any steady self-regulating cyclic action and for the cncrgy which steadil y supports its turning. In this case the circle lics on a piece of Aif CUnertt ~1<jefJ ~rer1 ~>r'y'~ youse fll~ ~(LGd0 'V 10 to 1.5 m en.; f:l\ dy rtLfJIQr graph paper rclating the prcssure in thc warm pool with the pressure in the cool current. Projecting either of these pressures onto a pressure-time graph gives the sine wave (rising, failing, rising, failing, etc.). In three dimensions, pressure, pressure and time, the curve is a helix powered IJy the steady convective cooling of the house. The cooling by convection is steady; the falling of cold and the rising of warm arc furced to alternate by the geometry. (Note: The reference hnc is not necessarily to perfect circles, sine waves nor s((:ady cooli ng.) First Village Unit No.1 (Santa Fe, NM, designed by Bill Lumpkins, fig. 12) Unit No.1 is a greenhouse-mass wall and fan-supplied roek storage type solar house. The two-story, south fac ing grl"l~nhouse is triangular, set between diagonally oriented twostory Iiving spaces. It also serves as circulation space to all rooms. The living space exterior walls arc very well insulated (7-112") and cement plastered both inside and out. There arc many nice things one can say about this extraurdinary building; there's the playfulness with which it was made and its playfulness with the sun. The thing I find most significant, however, is not its essentially 100 percent passive heating and cooling behavior, but the way in which architect Lumpkins re-interprets the normally drab meaning uf hallway lU become the central inviting gesture to both peuple and the climate. For me this focuses directly on one of the great architectural opportunities brought by the advent of passive solar design. The climate dynamics of the house are highly ordered but also highly complex. There arc several discrete individual behaviOrs nested within each other, each taking up where some other has left off. My description is limited to one series of such events having to do with the way this housc handles energy after primary gain, its odd habit of sending the warmest air currents into the safest places. This, combined with the factors which produce remarkably uniform nighttime temperatures seems to be the essential bonus factors which make this house so climatically successful; only two rooms received backup heating last winter. NU)ht-ti.n?C , Wl.n ler CeDI LI19 CDndd:.cot1'5 effected temp5. 5/"PW .":>U1 v\'()YC k~~ va nai:wrl'7 @) ~~ ® @ ~~, ~~ Vilrm Dtlft? ) l~drtl"',"9'" Q("C vlt!;~ ~r'GIc.(cl" 1 ~ t'.il:1~ .e~ntd:Lon .of trr.e CL!m!n(IX&>!!l CO A..." the \lIJ::n/m yr.:d (S 00 The mrm a l( faa I d. Re f!>e""~'!> o~ N::l(rtl aLf t;;>oild ovcr ~ ~ oc-h::Jut)tex:i. the ~i.ll up ceol ~Io~, bkxklr1,'f 4". ~law\n9 t-he Op 01 a V\Ot111 au--' pool behcnd ~ c air tt -es/::c:J~~c;.. t.bec.col L.OOI mrt-QLI\., ~r<:in.q a w,ldov a tJtro (lC) ceo! aU-- CUdbLrt. X u ax' GUd:Clln . of eGOI a;'- rc§:.servc-'? .~ ~ L-__________________________~__________________________~~________________________~I~ fig. 8,9,10
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