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U SI NG T H E A NAL Y S I S G RI D I N E COT E CT Jui nto w Li n As si st ant Prof es sor | Cal Po ly Pomo na De par tme nt of Ar chi te ctur e 3801 W. T emp le A ve | Po mona C A 91 768 | 909 869 67 74 | j ui nto wl in at csu pom ona do t e du No vemb er 4, 200 7 Day light ing The d ay li ght fa ct or ( D F ) is a very c omm on m et hod to mea sur e t he sub je ct iv e d ayl ig ht qua li ty in a r oom . I t repre sen ts th e ra ti o b et we en ind oor and ou tdo or il lu mina nc e lev el s, ex pre sse d in per cen t. The hi ghe r t he DF, the more na tur al li ght i s a vai la ble w it hin a sp ac e. E cot ect u se s th e Bu il di ng R ese arch Es tab li shm ent ( B R E) Sp li t - Fl ux met hod to c al cu lat e d ay lig ht fa ctor s. Th is meth od as sum es th at ther e are th ree se par ate comp one nt s, ig nori ng dir e ct sun li ght , o f t he na tura l l igh t t hat ca n r eac h a ny po int w ith in a bui ld ing . T he DF is sim pl y t he sum of e ach of the se thre e comp one nt s. DF = SC + E RC + IR C   

Sk y Co mpo nen t ( S C) - D ir ect ly fro m t he sk y, thr oug h an op en ing su ch a s a w i ndo w. Ex ter nal ly R ef lec ted C omp onen t ( E RC) - Re fle ct ed of f th e gr oun d, tre es or oth e r bu ild in gs . Inter na ll y Ref le cte d Com p onen t (I R C) - The i nter - r ef lec ti on of 1 a nd 2 o ff sur fa ces w it hin th e r oom.

Da yl igh t f act or va lue s a re gener al ly c al cul ate d u nde r an ov erca st s ky or in an a rtif ic ia l sk y whi ch s imu lat e s a sta ndar d CI E ove rca st s ky in ord er t o re pre sen t a W O R ST - C A S E S CE N A RI O t o be de si gne d f or. E co te ct cla im s t here i s n o poi nt to “de sig n a l ig hti ng sy st em bas ed on the br igh tes t d ay of the y ear as it ma y onl y occ ur o nc e or t wi ce dur ing the y ear and pe op le are v ery li ke ly to c los e t he bl in ds any wa y to prot ec t them se lv es from he at and glar e ”. T he y cla im th at it i s “m uch mor e sen si bl e i s t o de si gn for th e wors t - c as e sce nar io. ” Th eref ore:  The val ue s wi ll no t c han ge w ith di ffer ent d ate s or t im es and , a s t he ov erc ast s k y mo de l o nl y vari es w it h alt itu de,  Nor w il l t h ey b e a ffe cte d b y ro tat ing t he Nor th poi nt.  Thes e v al ue s ar e a pro per ty of the de si gn it se lf, no t the lo ca l e nv iron men t.  The o nl y p ara met ers th at affe ct da yl igh t f ac tor s ar e the geo metr y of the de si g n an d t he mat eri al s i t is made of . Ave r age DF Ap p ea ra n ce En e rg y im p li cation s < 2% Roo m l oo ks gl oom y. E le ctr ic li ght in g need ed mo st of the da y 2 % to 5 % Roo m a ppe ars pre dom ina n tly da yl it . Art if ic ia l l ig hti ng ma y b e r equ ired . T his v al ue str ike s a g ood bal anc e bet wee n d ay li ght ing an d t herma l fac tors . > 5% Roo m a ppe ars st ong ly d ay lit . Da yti me el ectr ic l ig hti ng is li ke ly no t need ed, bu t t her e e xi st s a pot ent ia l for t herm al pro bl ems du e t o over hea tin g in sum mer an d he at los se s in wi nte r.

Introduction to Ecotect v5.6 – Modeling © Juintow Lin 2007

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Anal ysi s G rid  Ope n t he fi le T herm al In tr o – ne w.e co fro m http:// ww w.to o lsfo rsu sta in ab i lity .com / fil es/do wnl oad/e cotect _m ode ls/ The r m al Intro - n ew .eco . ▫ Go to the pl an vi ew , se lec t th e f lo or o f Zo ne 1 Hi t o k  In t he ana ly si s gri d t ab, c l ic k “ Au to - F it Gri d t o Obj ec ts ” ▫ Se le ct W ith in T yp e o f F it ▫ Fit gri d t o Se le cte d O bj ect s ▫ Se le ct X Y A xi s wi th an A xi al Off se t o f 2 ’ ▫ Se le ct B oun dar y I nse t o f 0 .5 f or a ll a xe s 

Go to Gri d M ana gem ent ▫ Pl ay w ith th e numb er of ce ll s u nti l you ge t som eth ing tha t loo ks sq uar e. F or exam pl e, x=3 0, y= 12, z= 5. ▫ St art the C al cu lat ion Go to Ca lc ula ti ons a nd se l ect Li ght in g L eve l s → Per form Ca lc ul ati on. Wi zar d Pa ge 1 → Cho ose Nat ura l L igh t Lev el s Wi zar d Pa ge 2 → Se le ct Over th e An al ys is Gr id (do n’t ch ec k 3 D for no w) Wi zar d Pa ge 3 → Cho ose medi um r ay tra ci ng -

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Wi zar d Pa ge 4 → I npu t t h e Sk y I ll umi nan ce . I f you d on’ t k no w t he de sig n sk y, cal cu lat e it by c li ck ing on I’m not s ure – cal cu la te it for m e . T hen s el ect th e trege nz a f ormu la . ( Cho ose the C I E O ver ca st S ky C o ndi tio n – ma ke sur e t o che ck yo ur va lue s o n t he l ast s cree n ( som e t ime s th ey don ’t get up dat ed)

Go to the la s t s cree n a nd hit ok . Vi ew y our res ul ts. T he val ue s ar e r etur ned b y d efa ult i n d ay li ght fa ctor Not e t hat th e gr id da ta mi nimu m, ma xim um, an d c on tour s ar e a uto mat ic al ly se t . T ry t urn ing on th e con tour li ne s. T ry t urn ing of f t he gri d l in es.

Introduction to Ecotect v5.6 – Modeling © Juintow Lin 2007

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There should be a buffer, esp for daylight analysis, to avoid too high a reflection The grid should generally be 1’ or 2’ squares, depending on your project. The grid interpolates separate points between the intersections. Sky luminance varies with climate and cloud cover. By assigning a design sky value, it is possible to obtain illuminance levels (in Lux) for a particular location. A lux is a unit of measurement for the intensity of light. It is equal to the illumination of a surface one meter away from a single candle.

Daylight factor is the percentage of daylight coming in, including 1) sky component, 2) externally reflected component, and 3) internally reflected component (only one reflection). Radiance uses multiple reflections.

Ecotect sends rays from each point. If it hits wall, it will look at its reflectivity. If it hits a window, it knows to go to the sky.

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T ry cha ngi n g the c ont our val ue s Ref er t o t he tab le ab ov e a nd n ote th os e ar ea s t hat a re no be tw een th e r ang e o f 2- 5 % Da yl igh t F act ors . T ry cha ngi ng the m ini mum va lue t o 2 and th en ch ec k C li ck to Mi nim um .

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Cha nge to an a xon ome tri c vi ew (F8) an d tr y sho w ing va lue s in 3D .

Cha nge fro m Da yl igh t F a ct or to D ay li ght in g L eve ls to get I llu mi nan ce le ve ls. I t ju s t mult ip li es th e d ay lig ht fa ct or b y t h e de sig n sk y .

Introduction to Ecotect v5.6 – Modeling © Juintow Lin 2007

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4% daylight factor is adequate for most residential buildings.

Cl ic k Sh ow Aver ag e Va lue . N ote th e a ver age l ux va l ue. Ref er t o t he S zo ko lay ta bl e for i ll umi nan ce l eve ls . Find th e i l lum ina nc e v al ue s y ou sh oul d a im to de si g n for . Ad d s ome w in do ws to ac hi eve a sat is fa ctor y day li ght fa ctor as w el l as sa ti sfa ct ory il lum ina nc e l ev el s. Vi ew re su lts i n t he V is ual i se too lbar . Us e t he S ect io n Pla ne (z ax is) to ol in Vi su al is ati on S ett ing s. ▫ ▫ ▫ ▫

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Try cha ngi ng the i nter na l r efl ect iv it y o n t he mat eri al prope rti es Al so ch an g e the refr ac ti ve in dex of g las s ( tran sp are ncy fro m 0 .8 – 0 .3) Ad d a w al l, i.e . acro ss t he str eet , l it tl e s ky c omp one nt, more e xter na ll y re fl ect ed

Introduction to Ecotect v5.6 – Modeling © Juintow Lin 2007

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Com puta tion a l F l u id Dyn am ics ( CF D)  Ins tal l W in Air  Us e t he T herm al In tro Mod el.  Se le ct al l wi ndo ws an d ch ange th em to vo id s.  Ca lcu la te pre vai li ng w ind s (sh ow per ce nta ges an d le gend , cho ose a ll ye ar)

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Ad d a w ind ow to th e lee wa rd s ide of t he bui ld ing , i.e one w ind ow (8’ w x 4’ h wit h 3 ’ s il l) on t he we st en d o f t he nor th wa ll. T ur n t he wi nd di ag ram o ff by c li ck ing D is pl ay → Mode l. Go to the A na ly si s Gri d T a b – di sp lay th e a na ly si s gr id Ad ju st gri d e xte nt s a nd pu t a gri d o n . S ele ct Aut o - Fi t Gr id to Ob je ct s a nd se le ct: Aro und Al l Vi si bl e O bj ec ts , XY Ax is , s et a bou ndar y ins et of - 25 . Ma ke s ure th at t he z boun dar y i s zer o. T hen ma nua ll y c han ge it s hei ght . T ry t o m ake e ver yth ing c lo s e to cub es. Cha nge gr id man age men t so tha t x =30 , y=26 , a nd z =24

Introduction to Ecotect v5.6 – Modeling © Juintow Lin 2007

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Se le ct CF D Ce ll B lo ck age s a nd hit Perf orm Ca lc ul at ion s, se le ct bou ndar ie s Go to the E xp ort Man ager (righ t t ab) an d c li ck on Wi nA ir 4 , t hen c li ck on th e Sa ve ic on ▫ Sa ve the f il e a s Si mp le Ho use ▫ Se t t he S pee d /d ire ct ion Us e Wea t her T o ol to det er mine th e spe ed/ dir ec tio n , as we ll as te mper atu re . Us e a w ebs it e s uc h a s h tt p ://w ww .ook ingdom . com / m etr ic/ vel ocit y t o con vert mph to mps an d h ttp :// ww w.onl inec onve r sion. com / tem pe ratu r e.htm to con vert fr om Ce ls iu s t o F a hrenh ei t.

Pre vailing W inds

Introduction to Ecotect v5.6 – Modeling © Juintow Lin 2007

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Che ck on ly th e h ori zo nta l air flo w on ly bo x.

Ope n Wi nA ir. (C : \ W ina ir \ b i n \w in air4 .e xe) ▫ Load th e . geo f ile . ▫ Load th e con tro l f il e . CO N ( do th is ri ght a wa y) ▫ Se le ct out put f ile ( Sim pl e Hou se) ▫ Run th e d ata . Se t t he num ber o f iter at ion s. (20 0) ▫ Impor t t he CF D o utp ut . DA T fi le. F ile → Im por t → G ener al Dat a F ile s Se le ct CF D Out put D ata F i les a s t he fi le ty pe Loc ate yo ur S imp le Hou se . dat fi le. Wh en prom pte d, se lec t th e ne w form at ▫ Ex am ine th e An al ys is Gr id F lo w Ve ctor Und er g rid da ta and s ca le, sh ow fl ow v ect or Un che ck S ho w Gri dl ine s Che ck Gr id S qua res Un che ck S ho w con tour l in es

Introduction to Ecotect v5.6 – Modeling © Juintow Lin 2007

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F l ow R ate Und er g rid da ta and s ca le, se le ct air fl ow rat e Che ck Sho w Gri dl ine s Che ck Sha de Gri d Sq uare s Che ck Sho w Co nto ur L in e s

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Cl ic k o n t he arro w nex t t o con tour s, se le ct 3D v olu m etri c r end er, se le ct cub es, fa ded to m ini mum val ue s. P la y ar oun d wit h t he m in imu m v al ue unt il you ge t s ome re sul ts .

Introduction to Ecotect v5.6 – Modeling © Juintow Lin 2007

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T ry t o m in imi ze th e wi nd s peed s in the w in ter. Try a ddi ng tree s T ry t o m ax imi ze th e e ffe ct s o f n atur al ve nt ila ti on. Tr y a ddi ng ano the r win do w on t he nort h wa ll . See w hi ch lo cat ion w ork s bes t. U s e v ie ws (ca mer a) t o s ta y con si ste nt. F or y our ac tua l proj ec t, yo u s hou ld ti ght en up the gr i d mor e, so th at you c an see mor e a cc ura cy in th e f lo w v ec tors , etc .

T ry t o vie w the w in d f lo w v ect ors in 3d . u se th e s ec ti on p la ne and th e gr id ax es and off se ts to ana ly ze th e wi nd ve ctor s.

Introduction to Ecotect v5.6 – Modeling © Juintow Lin 2007

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So me inf orma ti on on wi nd spe eds .

Introduction to Ecotect v5.6 – Modeling © Juintow Lin 2007

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