lighting and shading control studies at pe trudeau airport

Motivation• The airport has several perimeter zones with very large glazedfacades, which receive significant solar gains throughout the year• They require efficient solar protection, in order to reduce coolingloads and demand and also prevent glare• These facades were shaded by motorized shades operatedmanually by the airport’s personnel• The building did not have efficient solar protection and excessiveenergy was spent for cooling

Research & demonstration project• A research project started in 2006 between Aeroports de Montreal(ADM), NRCan and SBRN• Integrated approach for shading, lighting and HVAC operation

Methodology flowchart

Phase 1 - Initial studySouth facing zone and west corner -53 m long and 7m high

Data acquisition and control system• Sensor data are read by the Delta controller– Reads light sensor signals– Input signals must be from 0-5 V or 4-20 mA– Monitor and control shade position– Monitor temperature data (14000 points)

Light sensors• Four LICOR 210 photometric sensors were used– Small size– Very light– Linear response– 10 s response time– Very accurate (5%)– Cosine corrected

Sensor positioning• Strategic location is important in order to examine the space indetail• Depend on space geometry, lights location space useBDELECTRIC LIGHTSCBASECONDFLOORCMOTORIZEDSHADESDACONTROLROOMFACADE

Measurements• The sensors’ readings were monitored under various sky conditionsand shade positions• The objective was to be able to predict interior illuminance based onthe ceiling sensors’ readings; horizontal sensors are visible andneeded to be removed after the test period• Then correlate with horizontal illuminance and control the shadesand the lights accordingly• Deciding the number of sensors and their location is a keyrequirement of the control methodology

13:28:353:44:1619:34:0110:54:161:39:0118:04:227:44:021:14:2313:49:028:24:2419:54:0315:34:241:59:0422:44:258:04:045:54:2614:09:0513:04:2620:14:0620:14:272:19:063:24:288:24:0714:29:0710:34:2820:34:0817:44:292:39:090:54:308:44:098:04:3014:49:1015:14:3120:54:1022:24:322:59:115:34:339:04:1212:44:3315:09:1219:54:3421:14:133:04:353:19:1310:14:359:24:1417:24:3615:29:150:34:3721:34:157:44:373:39:16Illuminance (lux)Illuminance (lx)Measurements and correlations180045001600400014003500120030001000250080020006001500400100020050000Sensor ASensor BSensor ASensor B

Sensor B (ceiling, lux)Correlations- low illuminances region12001000B = 0.71A - 2780060040020000 200 400 600 800 1000 1200Sensor A (horizontal illuminance, lux)

Sensor B (ceiling, lux)Correlations- high illuminance region2500B = 0.517A + 9620001500100050001000 1500 2000 2500 3000 3500 4000Sensor A (horizontal illuminance, lux)

Sensor B (ceiling)Final correlation400035003000B = 0.517×A + 96250020001500B = 0.71×A - 27100050000 500 1000 1500 2000 2500 3000 3500 4000Sensor A (horizontal illuminance)

Set points for lighting/shading control• Minimum required horizontal illuminance: 250 lux (electric lights atnight)• Lighting and shading control schemes were initially decoupled forsimplicity of operation• For lighting control, a new illuminance set point was selected forthe daytime (450 lux)• Lights turn off when ceiling sensor reads 300 lux or higher– This includes a 200 lux threshold to account for errors andinter-reflections– 15-min time interval to ensure stable conditions (after datacollection and averaging)

Set points for lighting/shading control• Shade position is modulated based on different set points• Shades will close when sunlight is present (ceiling reads 800lux with open shades =minimum 540 lux horizontal illuminance) toprevent from overheating and glare• For this value, lights will remain off; when the measured averageddata fall below the lighting set point, lights will turn on• Shades will open when the ceiling reading is less than 500 lux(>200 lux threshold)• Before implementing the control schemes in the airport, a similarexperimental setup was installed and tested and in the Solar andLighting Laboratory of Concordia University

Estimation of potential energy savings• Daylighting simulations for a full year using the ray-tracing softwareSPOT were performed in order to estimate the potential reduction inelectricity consumption for lighting due to daylight use• Calculation of average annual daylight autonomy (% of workinghours in a year during which natural light levels are adequate)• Lighting yearly energy savings:EL PL × ty× A×DA30,000 kWhrs/year (>50%)

Annual cooling energy demand (kWhrs)Estimation of potential energy savings• Thermal simulation model (finite difference) to estimate thepotential energy savings (due to reduction in cooling) from shading200000and lighting control 182000180000158000160000• Reduction140000in annual cooling energy: >13%120000• Reduction in peak cooling demand: >20%100000145000800006000040000200000No control Shading control Shading and lighting control

Phase 2: all perimeter zones• After successful implementation, the project moved to the nextphase in spring 2008• 17 large perimeter zones with different geometrical characteristicsand orientations• To avoid using a large number of sensors, only one ceiling sensor(and amplifier) was installed in each zone, and work planeilluminance was predicted using daylighting simulation models,validated with a few manual measurements

Workplane illuminance (lx)Measured vs simulated correlation data4000MeasuredSimulated3000Linear(Simulated)2000100000 200 400 600 800 1000 1200 1400 1600 1800 2000Ceiling illuminance (lx)

Fine tuning• Timed control was introduced for all west and northwest-facingzones, to control shades only in the afternoon –in the morning, theyremain open for maximizing daylight provision• Seasonal control was introduced by adjusting the lower limits ofshade position- based on measured temperature data, shades willclose no more than 75% when the outdoor temperature is higherthan 5 0 C to harness passive solar gains and reduce heatingloads

Fine tuning• The control operation was changed from “open-close” to a stepcontrol function which is enabled every 10 minutes. If theshades need to close, they move proportionally (10%)downwards. Depending on the averaged sensors readings in thenext interval, they will close another 10% if direct sunlight ispresent (higher set point limit) and so on• If the reading is between the minimum and maximum set point,they will remain in the same position for another 10 min. In thecase when the readings are below the lower set point, the shadeswill open by 10% and, after 10 min, they will move (or not)according to the next averaged signal

Conclusion• The control algorithms were successfully implemented in all airportzones in October 2008• The shades close and prevent from glare while there is still someview to the outdoors for the travelers• Lights now turn on/off based on the sensors’ readings• The airport administration will start measuring the energyconsumption in the summer for estimating the cooling energysavings due to shading/lighting control

Before and after

Acknowledgments• This work was funded by Aeroports de Montreal, NRCan(Sustainable Buildings & Communities group) and the CanadianSolar Buildings Research Network• The authors would like to especially thank Mr. Denis Boilard at ADMfor his kind help and support