J. Korean. Soc. Living. Environ. Sys. Vol. 14, No. 2, pp 117~125(2007) w y y w z sm Ÿ š w œ l ³Á½ * w, **w w w Impact of Photosensor Sensitivity on the Control Performance of a Daylight Dimming System Yong-Kyu Baik and Soo-Young Kim *Department of Architecture, Seoil College, Korea **The Research Institute of Industrial Science, Hanyang University, Korea Abstract : This study examines the control performance of a photosensor dimming control system in a small office according to three different photosensor sensitivity. Computer simulations were performed for the office with a double skin envelope system under various daylight conditions. Horizontal blind was considered to be installed on the external envelope and a retractable fabric shading device was installed on the internal envelope. Three sky conditions recommended by CIE were used at different times of a day and year. A partiailly-shielded photosensor was placed at the center of ceiling. Photosensor with the most sensitive level to daylight failed to achieve target illuminance providing less light output. The sensor with the least sensitive level provided excessive light output and resulted in overshooting the target illuminance. The sensor with medium sensitive level achieved good control performance and successfully provided target illuminance with reduced light output. The correlation between destkop illuminance and photosensor illuminance due to daylight was greater than 0.79. Reasonable lighting energy savings was achieved by the partiallyshielded photosensor with medium sensitivity. Key words : Dimming control, Photosensor sensitivity, Partial-shielding, Lighting energy 1. ü t y w» w» l.» w üœ ü ³ (uniform)w ù, ø»w. w wš w sm l (Photosensor Control System) š. l Ÿ(daylight) ü w» w œ y w w. ù ü w Ÿ(daylight) : ³ ( 131-208) p 8 49-3 w y y: 02-490-7529 E-mail: ykbaik29@seoil.ac.kr» yw, v (envelope design) w y dw». yw Ÿ z w» w üœ sm e, (shielding condition), sm (photosensor Sensitivity) š w. yw Ÿ w sm e (shielding condition) l sƒ ù, sm w e q (controller setting) w w š [Mistrick and Thongtipaya, 1997; Lee et al., 1999; Kim and Mistrick, 2001]. sm l w» w sm sƒw. ³ œ w w ful. 117
118 ³Á½ w yy wz 2. ful u 2.1. v w ful j (Lawrence Berkeley National Laboratory) v (Desktop Radiance Version 1.02) w. v v w w (modeling) ƒ 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 and Mistrick, 2003]., Ÿ» w sm (photosensor) y, l w Ÿ w» e dw. 2.2. œ Ÿ vƒ e ³ œ ƒ. j» s 3.0 m, ¾ 3.6 m, 2.7 m ƒ, ü v v 0.9 m. v œ»d w e p(cavity)ƒ. ü v ƒ. w 100% ƒ. n 0.6 0.07. e p n 0% ƒ üœ w w(overhang) w. e p d 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. (blind slat) 2.54 cm t 0.71. üœ w ü v w eƒ ƒ. ü v l 0%, 25%, 50% w. n 0.1 ƒ. w vƒ e ûd d w w ƒ. œ e e Fig. 1~Fig. 2 ùk ù. v œ ew œ (Michigan) (Ann Arbor) ƒ ( : 42 o 14', : 83 o 32'). t 0.1 Fig. 1. Layout of the room. Fig. 2. Shading condition.
sm Ÿ š w œ l 119 Table 1. Daylight conditions Orientation South North Day Time Shading on Window Internal 12/21 0% 3/21 8:00-17:00 25% 6/21 50% 12/21 8:00 3/21-17:00 6/21 0% External Horizontal Blind Horizontal Blind Sky Clear Inter -mediate Overcast ƒ. v ƒ w ƒ œ (Clear, Intermediate, Overcast sky). 12, 3, 6 ƒ 21, ƒ w. Ÿ Table 1 ùkù. 2.3.» e»»» s 60 cm(2 ft), ¼ 60 cm(2 ft) x ƒ. v 2.54 cm U xÿ ƒ»» 2. v w w 7.6 cm ¾ s xk ƒ e s w (parabolic fluorescent troffer).»» t ƒ w 3 w 4 ww.»» w 1236 cd,, l 67.5. 4»» w t 760 lx(70 fc) ƒ. sm (photosensor) (partially-shielded) e z ww ƒ. s m e e Fig. 1 Fig. 3 ùkù. (partially-shielded) sm (photosensor)ƒ w y w ƒ. v ƒ ƒ œ ww, ƒ e œ û. d». w ƒƒ 90 o ( 180 o ). œ ww ƒ 157.2 o w. 0.71 ƒ, x s m y w ƒ. sm w»» w»(controller) x w ƒ. š (control algorithm) Fig. 4 ùkù. 7 q x w d ùk ù 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 Fig. 3. Shielding condition of photosensor. Fig. 4. Control settings (Linear Algorithm).
120 ³Á½ (SSE: Error Sum of Squares) y w x z, ƒ w v w t 760 lx(70 fc) œ w [Kim and Yum, 2005]. 4. š 4.1. sm ew, ƒ œ w»(controller) w ƒ q Fig. 5~Fig. 8 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 Fig. 5. System performance (North-facing, 0% fabricshading, Top: December 21, Middle: March 21, Bottom: June 21). Fig. 6. System performance (South-facing, 0% fabricshading, Top: December 21, Middle: March 21, Bottom: June 21). w yy wz
sm Ÿ š w œ l 121 Fig. 7. System performance (South-facing, 25% fabricshading, Top: December 21, Middle: March 21, Bottom: June 21)., l sƒw» w q». ƒ l w l sƒ. t 40%ƒ Ÿ œ w l 5 ƒ. Ÿ w t œ w 40%~90% ƒ w (best) sƒ, w Fig. 8. System performance (South-facing, 50% fabricshading, Top: December 21, Middle: March 21, Bottom: June 21)., 15% (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) sw.
122 ³Á½ Table 2. Dimming control performance Date Dec.21 Mar.21 June.21 Performance north 0% south 0% south 25% south 50% Sky Setting Sky Setting Sky Setting Sky Setting Best * * * * * * * * Good C # 6 C # 4 * * * * Fail C, I, O # 11 C, I, O # 11 C, I, O # 11 C, I, O # 11 N/R I, O # 6 I # 4 C, I # 4 C, I, O # 4 C, I # 6 C, I, O # 6 I, O # 6 I/D C, I, O # 4 O # 4 O # 4 O # 6 Best I, O # 6 * * I # 6 Good * * O # 6 O # 6 C # 4 C # 11 I # 6 Fail C, I, O # 11 C, I # 11 C, I, O # 11 C, O # 6 C, I, O # 11 N/R C # 6 C, I # 4 C, I # 4 * * C # 4 C, I # 6 C # 6 I/D O # 4 O # 4 O # 4 I, O # 4 I # 4 Best I # 6 * * C # 6 * * Good O # 6 I, O # 6 I, O # 6 C, I, O # 6 Fail C, I, O # 11 C, I, O # 11 C, I, O # 11 C, I, O # 11 N/R C # 6 C, I, O # 4 C # 4 * * C, I, O # 4 C # 6 I/D * * * * I, O # 4 C, I, O # 4 t,» w l z z sƒ. Fig. 5~Fig. 8 ùkù ƒ œ w l q Table 2 ù kù. sm w» q y ùkü. ƒ ƒ q #11 q q., ƒ û sm ƒ w ƒ»»» w q #4, t w» ùkû. ƒ q ùkü w yy wz q #6 w ù kü. sm w» q w š w w ùkù q. sm ƒ w ƒ»» q»»» ùkù. sm ƒ e, y w Ÿ w ü t œ w» w sm w q»»» y sm ƒ w y 0.25 w q. š yw
sm Ÿ š w œ l 123 ùkü q #6, œ w yw ùkû. œ ùkù Ÿ s w q. d w, k l w w ùkû. k w œt l (direct component) w sm w z»» w q. ûd w, ƒ k š ƒ ƒw»» ƒw. k š ƒ w ü Ÿ ƒ w q. œ t œ z ùkû. ü w z, sm w w w z q. ü v e ƒw ü Ÿ. e n 0.1 ùkù q. œ sm w sƒ» œm. v l ³ œ ü sm w ùkü [Mistrick and Thongtipaya, 1997]. 4.2. Ÿ w sm»»» sm ƒ w y, y w. Ÿ Ÿ w» w, w xz. ùkü (r 2 ) z w ANOVA l p Fig. 9 ùkù. d w, 0.98 ùkù ùkû. d Fig. 9. Correlation between desktop illuminance and photosensor illuminance due to daylight (Top: Northfacing, Bottom: South-facing). w ûd 0.19 w ùkû. k l ü w q. ûd w e l w ùkù ƒ. d k l w, œt l Ÿ s w ƒ. 4.3.» sm w»» w». z» w» w ƒ q w s³ w. ƒ Table 3 ù kù. d w w k l Ÿ ƒ ûd w z
124 ³Á½ Table 3. Lighting energy savings [%] Day 12/21 3/21 6/21 Sky north 0% south 0% south 25% south 50 % # 4 # 6 # 11 # 4 # 6 # 11 # 4 # 6 # 11 # 4 # 6 # 11 C 31.3 39.8 65.3 76.6 79.5 86.9 73.1 79.2 86.7 67.9 72.7 84.9 I 26.0 33.2 58.1 45.2 58.6 79.5 42.9 55.0 77.9 33.0 41.8 67.5 O 26.1 33.2 58.2 26.0 33.2 58.1 25.7 32.8 57.7 23.9 30.6 55.3 C 43.1 54.3 81.2 79.5 83.8 91.6 76.8 83.3 91.0 49.7 63.5 86.7 I 33.1 41.9 67.6 47.7 60.0 85.8 46.1 57.9 84.9 34.6 43.8 69.7 O 32.6 41.3 66.9 32.5 41.1 66.8 31.8 40.3 65.9 27.1 34.5 59.5 C 45.0 56.6 83.8 52.9 68.3 88.7 50.6 64.8 87.7 35.7 45.1 71.2 I 34.7 43.9 69.9 38.5 48.6 74.9 37.4 47.3 73.5 29.8 37.9 63.3 O 37.3 47.2 73.4 37.3 47.1 73.4 36.4 46.0 72.1 29.4 37.3 62.6. d 39.7%, 47.1% ùkû œw l z q. ûd w k š ƒ ƒ w ƒw, œ ƒ œ w ùkû. sm k l w w, ü ƒ ƒw sm ƒw»» l ƒw w q. w yy wz 5. ful w sm l z sƒ w. w. 1. sm ƒ e Ÿ y w l w, sm w» q(controller setting)»» y sm ƒ w y 0.25 v w t z œ w q. 2. q, Ÿ y ƒ œ(clear sky) yw ùkû. w œ (overcast sky) t z œ, w Ÿ s w z ùkû. 3. Ÿ y sm Ÿ y k l w d ûd w 0.19 ùkû. ûd 0.79, sm w k l z wš z l z w q. 4. Ÿ y w sm w» z. d 47% ùkü. œ w z. 6. w wz p w š (computation algorithm)» w v w. Ÿ e w. š ƒ v w ùký d. x, w y v point by point method w luminous flux w w w lumen method w v ù. ƒ w w w w ùkû [Cho, 1997]. ù, p w v mw ùkù w, yw ƒ w q. w x d wz x d
sm Ÿ š w œ l 125 w w ƒ. z» 2006 w w w. x Mistrick, R.G. and Thongtipaya, J. (1997) Analysis of daylight photocell placement and view in a small office. The Journal of Illuminating Engineering Society of North America, 26, 150-160. Lee, E.S., DiBartolomeo, D. and Selkowitz, S. (1999) The effect of venetian blinds on daylight photoelectric control performance. The Journal of the Illuminating Engineering Society of North America, 28, 3-23. Kim, S. and Mistrick, R. (2001) Recommended daylight conditions for photosensor system calibration in a small office. The Journal of the Illuminating Engineering Society of North America, 30, 176-188. Ranasinghe, S. and Mistrick, R. (2003) A study of photosensor configuration and performance in a daylighted classroom space. The Journal of the Illuminating Engineering Society of North America, 32, 3-20. Kim, S.Y. and Yum, S.K. (2005) Optimum control of a photoelectric dimming system in a small office with a double skin envelope. Architectural Research, 7, 47-54. ½ (2004) ³ v w sm l. w wz, 20, 197-204. Choi, A. (1997) System modeling approach to the analysis of daylight dimming systems. The Pennsylvania State University Ph.D. Dissertation, Chapter 2. n š : 2007. 1. 3 : 2007. 5. 16 : 2007. 6. 21