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  • 1. - - 2159 & - ECOTECT

2. - (700-2300nm) - (380-700nm) 46% - (20-380nm)SOLAR ACCESS & SHADING - - 2159 3. . , . . - - 2159 4. . , . . thermal behaviour of buildingsQi+Qc+Qs+Qv = Ssolar heat gainventilation heat gain or lossconduction heat gain or loss internal heat gain - - 2159 5. Qi+Qc+Qs+Qv = SS > 0 int < TcomfQs thermal behaviour of buildings solar heat gain ventilation heat gain or loss conduction heat gain or lossinternal heat gain - - 2159 6. Qi+Qc+Qs+Qv = SS > 0 int < TcomfS < 0 int > TcomfQs thermal behaviour of buildings solar heat gain ventilation heat gain or loss conduction heat gain or lossinternal heat gain - - 2159 7. Qi+Qc+Qs+Qv = SS > 0 int < TcomfS < 0 int > TcomfS = 0 int = TcomfQs thermal behaviour of buildings solar heat gain ventilation heat gain or loss conduction heat gain or lossinternal heat gain - - 2159 8. Qs - - 2159 9. VS . - - 2159 10. d in the vertical plane, between the suns nd the horizontal; in some texts this is referred toon or profile angle ion measuredhorizontal plane of the sun , in the in a clockwise direction (thus east = 90o, south . d west = 270o, or 360o); whilst north can be 0 d to as bearing authors use 0o by some; many : northern hemisphere) and have -90o for n the (ALT), +90o for west, or the converse for the southern . 0o for north and going through east e, taking (), to d through west o. The convention here , to -180 the only one universally valid. ). ( ECOTECT Fig.6 Definition of solar position anglesmeasured between the suns direction and thementary angle of altitude: ALTesses the time of day with respect to the solarance, measured within the plane of the sunsween the suns position at the time considered. the solar meridian. (This is the longitude circlehich contains the zenith and the suns noon - - 2159 o o o 11. d in the vertical plane, between the suns nd the horizontal; in some texts this is referred toon or profile angle ion measuredhorizontal plane of the sun , in the in a clockwise direction (thus east = 90o, south . d west = 270o, or 360o); whilst north can be 0 d to as bearing authors use 0o by some; many : northern hemisphere) and have -90o for n the (ALT), +90o for west, or the converse for the southern . 0o for north and going through east e, taking (), to d through west o. The convention here , to -180 the only one universally valid. ). ( ECOTECT Fig.6 Definition of solar position anglesmeasured between the suns direction and thementary angle of altitude: ALTesses the time of day with respect to the solarance, measured within the plane of the sunsween the suns position at the time considered. the solar meridian. (This is the longitude circlehich contains the zenith and the suns noon - - 2159 o o o 12. d in the vertical plane, between the suns nd the horizontal; in some texts this is referred toon or profile angle ion measuredhorizontal plane of the sun , in the in a clockwise direction (thus east = 90o, south . d west = 270o, or 360o); whilst north can be 0 d to as bearing authors use 0o by some; many : northern hemisphere) and have -90o for n the (ALT), +90o for west, or the converse for the southern . 0o for north and going through east e, taking (), to d through west o. The convention here , to -180 the only one universally valid. ). ( ECOTECT Fig.6 Definition of solar position anglesmeasured between the suns direction and thementary angle of altitude: ALTesses the time of day with respect to the solarance, measured within the plane of the sunsween the suns position at the time considered. the solar meridian. (This is the longitude circlehich contains the zenith and the suns noon - - 2159 o o o 13. LT 21 9:00 - - 2159 14. LT 21 12:00 - - 2159 15. LT 21 16:00 - - 2159 16. 1.1 The full revolution takes 365.24 days (365 days 5 h 48 46 to be precise) and as the calendar year is 365 days, an adjustment is necessary: one The e revolv extra day every four years (the leap year). This would mean 0.25 days per earth year, which is too much. The excess 0.01 day a year is compensated by a one day adjustment per century. , . The plane of the earths revolution is referred to as the ecliptic. The earths , The fu 23 27, tilted 23.45o from the normal to the plane of the ecliptic axis of rotation is and between the plane of the earths equator and the (Fig.1). The angle .extraecliptic (or the earth - sun line) is the declination (DEC) and it variesyear,between +23.45o on June 22 (northern solstice) and -23.45o on Decemberone d22 (southern solstice, Fig.2).Fig.1 The Earths orbitThe paxis o(Fig.1ecliptbetw22 (so - - 2159 17. 21 10:00 - - 2159 18. 21 10:00 - - 2159 19. - - 2159 20. and at the pole the equinox sun-path would match the horizon circle, forpositions of the corresponding altitude circles on the horizon plane. Note the winter half-year the sun would be below the horizon and for the that the altitude circles (of equal increments) are spaced very closesummer half-year it would not set: it would spiral up to an altitude of 23.45otogether near the horizon and are widely spaced nearer the zenith.and then back to the horizon. Consequently such a graph would give a rather poor resolution for low Fig.11 Annual shifting of the sun-path planessolar positions. nadirFig.12Annual variation of the suns apparent path (drawn for 27 and -27 latitudes) 8 . - - - - .Fig.13 Equidistant chart Fig.14 Orthographic projectionFig.15 Stereographic projection9 - - 2159 21. - - 2159 22. - - 2159 23. - - 2159 24. - - 2159 25. - - 2159 26. - - 2159 27. - - 2159 28. - - 2159 29. can - horizoconsi . conta Fig.30 Vertical shading devices giving the : same horizontal shadow angle (HSA), , - - 2159 30. can - horizoconsi . conta Fig.30 Vertical shading devices giving the : same horizontal shadow angle (HSA), , - - 2159 31. can - horizocons . contaFig.30 Vertical shading devices giving the :same horizontal shadow angle (HSA), , - - 2159 32. 3 SHADING DESIGN Fig.29 Horizontal shadow angleshading mask can be constructed (traced). The shading mask will be devices employs two shadow angles: HSA and and ca given orientation VSA. - sectoral in shape (Fig.35). This shading mask, when superimposed on the (i.e. the shadow producesun-path diagram (according to the orientation of the building), will cover Solar radiation incident on a window consists of three components: beam-all the time-points (dates and hours) when the point considered will be inshade (Fig.36). 3.1 Shadow angles (direct-) radiation, diffuse-(sky-) and reflected radiation. External shading Fig.34 HSA of a pair of vertical finsHorizontal shadow angleFig.37 shows the section of a window, with a canopy over it. The line devices can eliminate the beam component (which is normally the edge of the the window sill gives the connecting the canopy to shadingShadow angles The design suns position and the ori largest) and reduce the diffuse component.express the suns position in relation , line of the protractor is the VSA HSA line. The angle between this and the horizontal VSA thisthe device. Ifof of such shadingthe corresponding arcualis traced,will give the . Fig.29 Horizontal shadow anglethe edge of the shadow devices employs two shadow angles: HSA and and can be used either to describegiven orientation VSA.shading mask of the canopy (Fig.38). Placed over the sun-path diagram itFig.37/a Horizontal devices giving the same will cover the times when the device is effective (Fig.39). superimposed on sun-path diagram VSAFig.36 as 35,(i.e. the shadow produced by) a given device or to AHSA = spBy convention, this is 3.1Shadow anglesFig.35 Shading mask of the vertical finsHorizontal shadow angle (HSA) is the difference in>aorientation (when AZIsuns position in relation to a (when AZI < ORI). When Shadow angles express the suns position and the orientation of the building face building face of Fig.29 Horizontal shadow angle is behind the facade, th given orientation and can be used either to shadow falls on the point consideredthe edge of the describe the performance ofgives two further check (i.e. the shadow produced by) a given device or to AZI - ORI device.HSA = specify aangle describes the peBy convention, this is positive when the sun isorientation (when AZI ORI) showsnegative when the Horizontal shadow angle (HSA) is the difference in>azimuth between theand that many combshading performance.oposition and the orientation of AZI < ORI). When the HSA is between +/- 90 a suns 16 (when the building face considered, wheng.29 Horizontal shadow angle the edge of Horizontal devices givingfalls on the point consideredFig.36facade is inon sun-path diagram Fig.37/a the shadow the same VSA is behind the facade, the as 35, superimposed shade, there i(Fig.29):HSA = AZI - ORI gives two further checks for The vertical shadow . an results beyond 270o Thmeasured on a plane pangle describes the performance of a vertical sha By convention, this is positive when the sun is clockwise from theonly when the HSA is be orien