Resource Stewardship and Sustainability: Lighting Systems

The Facility Service group is taking the following actions to reduce the environmental impact of Baylor College of Medicine operations through the following lighting systems initiatives:

In large scale operations it is important that all energy delivered to a site be used efficiently as possible. The measure of power conversion efficiency within a facility is described or defined by the "Power Factor" (PF). An electric strip heater has a power factor of 1.00 because all the electricity used is converted to heat where as an electric motor may have a power factor of 0.80 because only 80 percent of the electric power consumed is converted into rotational energy. Power companies have to transport more power to consumers who have lower power factors to make up for these facility losses. This increases costs for power generation and infrastructure capacity (larger distribution wiring) and these costs are passed on to the customer. Low power factor facilities are also responsible for increased green house gas production when compared to facilities with higher power factors. A facility should strive to have a power factor between 0.96 and 0.99. At Baylor College of Medicine we have continually upgraded our capacitor systems to maintain a power factor of .97 or higher as our electrical load has changed over the years. Our first capacitor system adjustment was performed in August 1991 at a cost of $22,000 and a payback of just 5 months. This work increased our power factor from .94 to .98 and resulted in a savings of $4500 per month. The savings associated with this type of project will show up in reduced Transportation and Distribution (T&D) charges. These charges are different for each utility. So the dollar savings at a facility will vary but the positive environmental impact that increasing the power factor has as a result of reduced electrical production will be substantial for every facility.

In 2001, in response to the indoor air quality issues after Tropical Storm Alison, we installed UV lights in every air handling unit on the campus. The lights kill the bacteria and mold growing in the moist cool environment inside the air handling units and the bacteria growing on the cooling coils. These bacteria had been responsible for trapping and holding dirt on the coil which decreased the heat transfer from the chilled water to the air flowing through the unit and increased the fan power required to move the air through the cooling coil because of an increased static pressure across the coil. The UV light installation provided both an improvement in the indoor air quality at the college and an energy savings bonus. The energy savings resulting from the installation of the UV lamps was roughly five percent per unit or 475,000 KWH per year ($45,125 per year).

Lighting technology advances every year. The yearly advancements are cumulative and after roughly 12 years, the lighting system technology advances to the point where it is worth changing the whole lighting system at the college. In 1992 and in 2004 we changed out all the lighting system ballasts and lamps to improve the efficiency of the lighting system at BCM. Each time the project resulted in a savings of over 1.5 million KWH per year. Our current lighting system is more than 50 percent more efficient than and saves more than 3 million KWH when compared to the lighting system we had in 1990. The savings have been over $140,000 per year.

As lighting technology has advanced we have been able to replace almost all the incandescent lights at the college with fluorescent lights. The newest florescent lamp technology is dimmer-switch compatible and uses only 21 watts of energy to replicate the light output of a 100 watt incandescent lamp. We began using these lamps in 2002 and continue to install them throughout the college as the technology advances to meet the use requirements. We recently completed a relamping project in the president's office using these lamps that yielded a savings of 3,800 watts per hour ($1,125 / YR; one year payback).

The motion detector technology has advanced along with lighting technology. Using the current devices, it is cost effective (one year payback or less) to replace manual light switches with the motion detector switches when a room has as few as 8 light fixtures. Using the motion detector switches saves BCM over 195,000 KWH ($18,500) per year.

We utilize our energy management system to schedule hallway lighting to match occupancy. In this program, our emergency lighting systems remain on at all times to provide the life safety illumination required by NFPA, but we turn on and off our normal power light fixtures (approximately 2/3 of the total # of light fixtures) to match the hours of occupancy of the facility.