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1 J. Korean. Soc. Living. Environ. Sys. Vol. 15, No. 2, pp 145~154(2008) w y y w z 15 «2 y 2008 ³ l w sm ½ Á yáy * w y w, ** w w Recommended Sensitivity of a Fully-shielded Photosensor for a Daylight Dimming Control System in a Small Office Soo-Young Kim, Yong-Ho Jung and Bong-Jae Hong *Dept. of Housing and Interior Design, Yonsei University, Seoul, Korea **Dept. of Building Service Engineering & Fire Protection System, Chungwoon Univ., Chungnam, Korea Abstract : This study investigate the control performance of a photoelectric dimming control system to recommend better photosensor sensitivity. Computer simulations were performed for an office space with a double skin envelope system. Various daylight conditions were applied to the space. Standard three sky conditions by CIE was used. A photosensor with a full shielding condition was assumed to be positioned at the center of the ceiling. Three sensitivity conditions were applied to the photosensor. Overall, desktop was overshot when the photosensor had the least sensitiveness level to daylight. In general, the dimming amount controlled by most sensitive level was too less to provide target illuminance. In some cases, the least sensitiveness level achieved the target illumiance with good energy savings. The coefficient of determination for the desktop illuminance due to daylight and photosensor illuminance due to daylight ranged from 0.74 to Key words : Daylight, Photoelectric dimming control, Sensitivity, Shielding, Energy savings 1. ü ü» l w œ. w» œ ³ w s w ö w. üy y w š (Ne'eman et al., 1984). ƒ w wš Ÿ» w w p l(daylight dimming system). ù l s š (Love, 1993).» yw : ½ ( ) 134, w y w y y: sooyoung@yonsei.ac.kr 145 Ÿ» w ü ƒ yw». w w» w sm e (Rubinstein et al., 1989; Mistrick et al., 1997; Kim et al., 2001). ù, sm e w e w»ƒ š, e z. sm w» q(controller setting) yw t œ w. sm q w» w w Ÿ w ful. 2. ful 2.1. v w ful

2 146 ½ Á yáy j (Lawrence Berkeley National Laboratory) v (Desktop Radiance Version 1.02) w. v v w w (modeling) ƒ w (Lawrence Berkeley National Laboratory, 2000). w, le (Monte Carlo) w Ÿ» (Ray-tracing techniques), Ÿ»» w d œw. w e, y (illuminance), { (luminous) d ƒ w. Ÿ d v w» (turbidity) p ùkü š ƒ» v w, x x w e w œw ùkû (Ranasinghe et al., 2003)., Ÿ» w sm (photosensor) y, l w Ÿ w» e dw œ Ÿ vƒ e ³ ƒ w w. j» s 3.0 m, ¾ 3.6 m, 2.7 m, ü v v 0.9 m. v e p(cavity)ƒ. üá v 100% ƒ, n e p n 0% ƒ üœ w w (overhang) w. e pd n 0.6 ƒ. üt 0.8( ), 0.5( ), 0.2( ). j» ƒ 1.5 m, 0.75 m, 0.75 m, t 0.3 ƒ. ü v 2.02 m e, üœ û d ƒ. e p wš v (Venetian) ƒ s e v w ƒ. ƒ (blind slat) 2.54 cm t üœ w yy wz w ü v w eƒ ƒ. ü v ó l 0%, 25%, 50% w, e n 0.1 ƒ. w vƒ e ûd d ww ƒ. œ e e Fig. 1, 2 ùkù. v œ ew œ (Michigan) (Ann Arbor) ƒ ( : 42 o 14', : 83 o 32'). t 0.1 ƒ, v ƒ w ƒ œ (Clear, Intermediate, Overcast sky). 12, 3, 6 ƒ 21, ƒ w. Ÿ k š, ƒ Table 1, 2. Fig. 1. Layout of the room. Fig. 2. Shading condition.

3 ³ l w sm 147 Table 1. Daylight condition Orientation Day Time South North 12/21 08:00 3/21-6/21 17:00 12/21 08:00 3/21-6/21 17:00 Shading on window Internal 0% 25% 50% 0% External Horizontal Blind Horizontal Blind Sky Clear Intermediate Overcast Table 2. Altitude and azimuth Altitude Azimuth Time 12/21 1/21 2/21 3/21 4/21 5/21 6/21 8 ** ** ** ** » e»»» s 60 cm(2ft), ¼ 60 cm(2ft) x ƒ cm U xÿ vƒ ƒ»» 2. v w w 7.6 cm ¾ s xk ƒ e s(intensity) w (parabolic fluorescent troffer).»» t ƒ w 3 w 4 ww.»» w 1236 cd, w» w l 67.5 v l.»» w w sš Fig. 3. 4»» w t 760 lx(70 fc) ƒ. sm (photosensor) (fullyshielded) e z ww ƒ. sm e e Fig. 1 Fig. 4 ùkù. sm (photosensor) w w» w (fully-shielded) ƒ., s 360 œ ww ƒ 67.2 w 15 «2 y 2008

4 148 ½ Á yáy Fig. 3. Power distribution of luminaire (Lighting Technology. Inc., 2006). Fig. 4. Shielding condition. Fig. 5. Control setting (Control Algorithm). w yy wz ƒ, x sm y w ƒ. ƒ w Ÿ» y sm. s m w»» w»(controller) x w ƒ. š (control algorithm) Fig. 5 ù kù. 7 q x w d ù kù sm ƒ w y» š 100% 10% w. 7 3 (#4, #6, #11).» Ÿ» w. ƒ l sƒw» w, ƒ yw Ÿ» w t œ v w». Ÿ w w (SSE: Error Sum of Squares) yw x z, ƒ w v w t 760 lx(70 fc) œ w. 3. š 3.1. sm ew, ƒ œ w»(controller) w ƒ q Fig. 6-Fig. 9 ùkù. v ƒ l» l w, ƒ q (dimming) ùkü.»» Ÿ ww t œ w. ùkù t œ w» w v w»»» (optimum dimming) w. yw Ÿ, l sƒw» w q».

5 ³ l w sm 149 Fig. 6. System performance (North-facing, 0% fabricshading, Top: December 21, Middle: March 21, Bottom: June 21). ƒ l w l sƒ. t 40%ƒ Ÿ œ w l» w 5ƒ (Kim et al., 2001; Kim et al., 2007). Ÿ w t œ w 40%~90% ƒ w (best) sƒ. w, 15% ü Fig. 7. System performance (South-facing, 0% fabricshading, Top: December 21, Middle: March 21, Bottom: June 21). (good) sƒ. 30% w ùkü l q(fail) sƒ. 30% w» ùkü «w(not recommended). ó, 10% ü w ù, 30% l Ÿ w w w q w Ÿ (insufficient daylight) w. t, 15 «2 y 2008

6 150 ½ Á yáy Fig. 8. System performance (South-facing, 25% fabricshading, Top: December 21, Middle: March 21, Bottom: June 21). w l z z sƒ. Fig. 6-Fig. 9 ùkù ƒ œ w l q Table 3.» q»»» l yw. wš w w, ƒ q»» w t œ w ùkû., sm w ƒ (viewing angle)ƒ 67.2 w w yy wz Fig. 9. System performance (South-facing, 50% fabricshading, Top: December 21, Middle: March 21, Bottom: June 21)., ü Ÿ y ƒw sm y w ü yw q. Ÿ w sm w» q yw. ƒ ƒ û #4 w» w t œ w., sm q w Ÿ y w w» q

7 ³ l w sm 151 Table 3. Dimming control performance Date Dec.21 Mar.21 June.21 Performance North facing South facing 0% shading 0% shading 25% shading 50% shading Sky Setting Sky Setting Sky Setting Sky Setting Best * * * * * * * * Good * * * * * * C, I # 6 Fail C, I, O # 11 C, I, O # 11 C, I, O # 11 C, I, O # 11 N/R I/D. ƒ ƒ q #11, w ƒ t 760 lx w qw. ù, t 15% ww w 650 lx w, ƒ w z w q (Kim et al., 2001). w q #6 yw ùkû. ƒ û t w ùkû. sm l ü w, ü Ÿ ƒw»» l œ w. ù,» q * * C, I # 4 C, I # 4 * * C # 6 C, I # 6 C, I, O # 4 O # 4 O # 4 C, I, O # 4 C, I, O # 6 I, O # 6 O # 6 O # 6 Best * * * * I # 6 * * Good Fail N/R I/D * * C # 6 C # 6 * * C # 11 C # 11 C, I, O # 11 C, I # 11 I, O # 11 C, I, O # 11 C # 6 C, I, O # 4 C, I, O # 4 C, I # 4 * * C, I, O # 6 I, O # 6 I, O # 6 * * * * O # 4 * * O # 6 Best * * C # 11 C # 6 * * Good C # 11 I, O # 11 I # 6 * * Fail I, O # 11 * * C, I, O # 11 C, I, O # 11 N/R C, I, O # 4 C, I, O # 4 C, I, O # 4 * * C, I, O # 6 C, I, O # 6 * * * * O # 6 C, I, O # 4 I/D C, I, O # 6 where, C: Clear sky, I: Intermediate Sky, O: Overcast Sky, N/R: Not recommended, I/D: Insufficient Daylight. yw. w q sm w w ƒ sm ƒ»»» l w., w, sm ƒ w w, Ÿ w q w w t z q. vƒ ³ œ sm w l e, Fig. 5 ùkù q #6 y (%) sm ƒ w y (lx) 0.25~0.30 w w œ 15 «2 y 2008

8 152 ½ Á yáy w q. yw ƒ ƒ œ, œ(clear sky) ùk û. œ yw Ÿ sƒ yw q. ù, sm ƒ e» ùkù e w ù, e w w ùkû (Rubinstein et al., 1989; Mistrick et al., 1997). k œ t (Sky surface) l v m w ü Ÿ sm w œ q. w z l œ ü Ÿ y w w w w ùkù q Ÿ w sm sm l, Ÿ y w sm y w» y. sm Ÿ y yw Ÿ y t œ w w w., Ÿ y w Ÿ y sm Ÿ y xz (linear regression) w w. z z, 5% (significance level) w ANOVA l p w w. ùk ü (r 2 ) Fig. 10-Fig. 11. k l w d ww ùkù q. Ÿ ƒ š, sm r (variation of photosensor illuminance) 93.5% j w. k w ûd ww, sm w ùkù d w 18.9%. Ÿ ƒ z š, sm r ƒ d w sw w yy wz Fig. 10. Correlation between desktop illuminance and photosensor illuminance due to daylight (North-facing). Fig. 11. Correlation between desktop illuminance and photosensor illuminance due to daylight (South-facing). w. k l w ƒ. ûd, y ƒw sm y w ƒ w ƒ ƒ û w. d, k w š sm ƒ w ûd w ùkù ƒ. 3.3.» s³» ƒ q» w. Table 4 ùkù. œ ƒ t ƒ s³ 33.36% 90.42% yw. ûd d w

9 ³ l w sm 153 Table 4. Lighting energy savings (%) Date 12/21 3/21 6/21 Sky North, 0% shading South, 0% shading South, 25% shading South, 50% shading # 4 # 6 # 11 # 4 # 6 # 11 # 4 # 6 # 11 # 4 # 6 # 11 C I O C I O C I O z. ƒ w sm ( q #4), ƒ z. z w t 15-18% w œ w. t ƒ ƒ w ww 600 lx~650 lx w z q. û d k š ƒ ƒw», œ œ z.» ew (Rubinstein et al., 1989; Mistrick et al., 1997; Kim et al., 2001). 4. sm l, sm q wš. w. 1. sm ƒ e l,»» y (%) s m ƒ w y (lx) 0.25~0.3 ü» q w œ w d., 0.3 t 650 lx w z w q. 2. yw œ(clear sky) ùkû. œ yw Ÿ sƒ l v w Ÿ ü q. œ(overcast sky) w Ÿ œ z z q. sm w w ƒ œ. 3. Ÿ w sm xz, d ûd ùkù y q. ù, z»»( Ÿ y/sm Ÿ y)ƒ ƒ sm w z w d. 4. ƒ z w w s³ 33.3% z. t ƒ 600 lx~650 lx š,»» y (%) sm ƒ w y (lx) 0.25~0.3» q, w t œ wì z d. 5. w wz w Ÿ w p w š ƒ v w w. p ƒ š w ùký. sm p w xxk w» w w ƒ ƒ v w q. x d w z 15 «2 y 2008

10 154 ½ Á yáy ƒ. x Ne'eman, E., Sweitzer, G. and Vine, E. (1984). Office worker response to lighting and daylighting issues in workspace environment: a pilot study. Energy and Buildings, 6, Love, J. (1993). Field performance of daylighting system with photoelectric controls. The Proceeding of the IESNA, Huston TX, USA, Rubinstein, F., Ward, G. and Verderber, R. (1989). Improving the performance of photo-electrically controlled lighting systems. The Journal of IESNA, 18, Mistrick, R. and Thongitipaya, J. (2002). Analysis of daylight photocell placement and view in a small office. The Journal of IESNA, 31, Kim, S. and Mistrick, R. (2001). Recommended daylight conditions for photosensor system calibration in a small office. The Journal of IESNA, 30, Lawrence Berkeley National Laboratory (2000). Desktop Radiance User Manual, Ranasinghe, S. and Mistrcik, R. (2003). A study of photosensor configuration and performance in a daylighted classroom space. The Journal of IESNA, 32, Kim, S. and Song, K. (2007). Determining photosensor condition of a daylighting dimming control system using different double-skin envelope system configuration. Indoor and Built Environment, 16, Kim, S. and Yum, S. (2005). Optimum control of a photoelectric dimming system in a small office with a double skin envelope. Architectural Research, 7, n š : : : w yy wz