Reducing Energy Consumption: The Role of Lighting
A key component of Sustainability in any setting is to reduce energy consumption (fuels and electrical). Recall that power-generating plants consume carbon fuels to operate, contributing to greenhouse gas (GHG) emissions. It is estimated that lighting accounts for approximately 12% of electrical use nationwide and 18% in New York City-owned buildings. Reducing energy consumption by lighting has significant impact in terms of energy costs and GHG emissions.
Reduction of electrical usage is accomplished by a variety of means, which can be grouped into three primary types of approaches: replacing existing equipment with more energy-efficient lighting, using lighting only when occupants are present in a space, and Daylight Harvesting.
Installation of energy-efficient lighting. Different types of lamps (i.e. light bulbs) require vastly different amounts of wattage to produce the same amount of illumination. Electrical energy supplied to the lamp is used by the lamp to generate light - and heat, as a by-product. The more energy-efficient the lamp, the more light and less heat it generates. Click here for a comparison of energy consumption by incandescent, fluorescent, Light Emitting Diode (LED), and halogen lamps.
Campus lighting projects take into account specific use and maintenance considerations of each location and application. Replacing existing lighting with LED lamps require that the LED perform (in terms of providing proper illumination for the application) equally or better than the lights they are replacing. Selection and installation was accomplished through a joint effort between Campus Planning & Facilities, Buildings & Grounds, campus electricians and end users. Lighting projects to date (March 2016) are listed here.
Motion-activated sensors to turn on/off lights. In many campus locations, lights are normally left on until they are manually turned off by the occupants of the space upon leaving. For this reason, spaces that are occupied sporadically throughout the day can be equipped with motion-activated controls that automatically turn on and off lights. Sensors have been installed in all restrooms, classrooms and offices in all buildings at Lehman College. Campus buildings typically shut down at 11 pm, non-essential lighting can be automatically shut down as well, leaving on emergency lighting only. This approach is planned for the hallways in Carman Hall.
By making an adjustment to the cleaning schedule from after hours to evening hours, we have been able to completely turn off lights overnight (midnight to 6 am) in the Library, Old Gym and Student Life Buildings.
Daylight Harvesting. This approach uses natural daylight to supplement artificial lighting, and is used throughout Science Hall. Sensors are installed that regulate the amount of light supplied by electrical lighting, so that lighting near the windows is dimmed, or shut off completely, and lighting that is further away from the windows is brighter. Spaces with “window walls” are good candidates for daylight harvesting. This approach has to be balanced against strong outdoor sunlight overheating a space; heat-resistant window shades that allow light through, but block direct sunlight have been installed as well (Carman 3rd floor classrooms). Daylight sensors for daylight harvesting have been installed in Apex 200-level corridor, and in the basement/1st/2nd floor window-wall transition space between Music and Speech & Theater buildings.
- The Nobel Prize in Physics 2014 awarded to Isamu Akasaki, Hiroshi Amano, Shuji Nakamura for having invented a new energy-efficient and environment-friendly light source – the blue Light-Emitting Diode (LED).
- Revolution Lighting Technologies' Tri-State LED Completes LED Lighting Retrofit Throughout Lehman College Campus. Yahoo Finance news, 02/16/2016.