Agenda - 10-19-1993 - VII-B - Laserfiche WebLink

Browse Search

"637 °4111' DAVIE HALL BLDG # 013 Case Study 36% Reduction in Annual Kilowatt Demand from 122 to 78 Davie Hall, located on the campus of the University of North Carolina at Chapel Hill, is currently illuminated by fluorescent fixtures with T-12 lamps and standard core and coil ballasts, and some incandescent fixtures. The current lighting system requires 468,593 kilowatt hours per year and costs $44,294 to operate. The Energy Office presented a proposal to save energy while maintaining or improving upon current lighting levels. The proposal includes replacing all existing 4X4 fixtures with standard core and coil ballasts and up to eight 34 watt T-12 lamps, with 2X4 fixtures with four 32 watt T-8 lamps and electronic ballasts. All other existing fixtures with T-12 lamps and standard ballasts will be retrofitted to have T-8 lamps and electronic ballasts. These changes increase lumens per watt from 66 to 100 in those fixtures. In addition, incandescent fixtures will be replaced with fluorescent fixtures. The proposal also includes the installation of motion detectors in all offices, classrooms, lounges, and meeting rooms, resulting in a one-third reduction in annual kilowatt hours in those rooms. The new lighting system reduces overall watts per square foot by 35%, from 1.7 to 1.1, while increasing lumens per watt from 62 to 95. Annual kilowatt demand reduces by 36%, from 122 to 78. This system costs $80,912 to implement with a payback of 4.1 years. Original System New System Cost per KWH $.084 $.084 Annual Maintenance Cost $4,932 $4,192 Annual Energy Cost $39,362 $23,347 Annual Operating Cost $44,294 $27,540 Total KWD 122 78 Annual KWH 468,593 277,946 COST ANALYSIS Implementation Cost $80,912 Net Operating Savings $16,754 Cooling Savings $3,203 Total Annual Savings $19,957 Payback 4.11 Internal Rate of Return 24% Prepared by Lynne G. Yellin 08/19/92