High Performance Lighting Terry Egnor Senior Consultant NBI
Design Issues Energy Efficiency is not difficult Lighting Quality is not difficult Together, it is a challenge GOAL: Energy Effective Lighting Illuminating Engineering Society of North America, Lighting Handbook, 9th Edition.
Basic Lighting Strategies Use high efficiency fixtures Use task lighting for primary visual task if possible Don t over light for ambient conditions Offices general lighting: 30-40 fc average, not 50+. Classrooms general lighting: 30-50 fc average, not 50+ Use light colored finishes Light colored space (Reflectivity: 80% ceiling, 70% walls) Incorporate Daylighting Fenestration design and glazing performance Light level sensors Controls Occupancy control or vacancy control Coupled to plug load, daylighting and HVAC
Intelligent Lighting in Offices Workspace-specific, suspended Separate up-down for layered controls Personal control for dimming downlight Research shows 20% improvement in worker comfort and improved motivations 60-80% energy savings! Light Right Consortium research project, Albany, NY. www.lightright.org for findings
High Performance T8 Savings Technology Light Output (MLPW) % Efficacy Improvement Over Generic T8 Generic T8 32-watt 700 series with rapid-start electronic ballast Super T8 32-watt 800+ series with program-start electronic ballast Super T8 32-watt 800+ series with instant-start electronic ballast 75 N/A 92 23% 98 31%
Task and Ambient Lighting Task/Ambient Promotes using lower ambient lighting and better-than-normal task lighting. Relies heavily on good task lighting. Only appropriate for projects that allow for extra attention to this detail. Don t rely on furniture supplier task lights to do the job. One solution: 1 lamp T5 or LED task lights over tables and desks
Integrated Daylight Controls Potential savings of 10% to 50%
Lighting Control Requirements Automatic Lighting Reduction Offices 300 s.f. automatic occupancy sensor All other spaces, automatic occupancy sensor or time device Bi-level or Continuous Control In Daylit Areas Reduce connected load uniformly by at least 50% Skylights - photocells for 50% reduction in load
Controls and Energy Savings Advanced Lighting Controls Tested Savings of occupancy sensors vs. dimming was dependent on occupant behavior Control Strategy Energy Saved Single Level Switching 0% Bi-Level Switching 23% Occupancy Sensors 20-26% Dimming - Photo Sensors 27% Occupancy and Photo Sensors 46% Dimming - Task Tuning 23% Office building, 7 months, 5 controls scenarios, April 2000, http://eetd.lbl.gov/btp/pub/lgpub.html
Occupancy Sensors Available in Passive-Infrared & Ultrasonic Most common problem is mis-application
Occupancy Sensors Range of Effectiveness Sensitivity Infrared - covers areas in beams - smaller range - lower sensitivity Ultrasonic - covers area evenly - larger range - highly sensitive (can be susceptible to false triggering from air currents)
Time clock vs. Occupancy Sensors
Outdoor Lighting Efficacy 60 lumens/watt or better Motion Sensor control Exceptions (monuments, safety, pools, LED, etc) Controls-photosensors or timeclocks Cutoff Fixtures
ABSIC / CBPD Guidelines for High Performance Lighting Provide daylighting as a dominant light source Separate task from ambient lighting Introduce direct-indirect lighting to reduce shadowing and create spatial dynamics Maximize lighting quality with high performance luminaires Provide for re-configurability by design for continuous change in zones and technologies Pursue innovative lighting system integration for thermal and air quality, resource conservation & environmental health. Advanced Building Systems Integration Consortium / Center for Building Performance and Diagnostics Carnegie Mellon University
ALG Online Advanced Lighting Guidelines Online Comprehensive coverage Detailed examples Design tools Continuous updates Available this Fall: http://www.advancedbuildings.net/algonline.htm