A Manchester, NH T.J.Maxx shopping plaza parking lot has been retrofitted with BetaLED luminaires. CBT Development of Greenland, NH was incurring high costs for parking lot maintenance from frequent lamp replacement in high pressure sodium (HPS) and metal halide (MH) fixtures. While poor power quality was causing the premature lamp failure, the developer was ready to replace the 25-year old luminaires with new, efficient technology. The parking lot covers approximately 151,000 square feet and has 385 parking spaces.
The Woburn, MA-based property manager CW Companies teamed with CBT Development consultants, BetaLED, and the U.S. Department of Energy (DOE) to design the shopping center's lighting system. Using the 13 existing poles and pole locations, the parking lot was retrofitted with 25 of BetaLED's THE EDGE® area square luminaires — replacing 28 HPS and six MH luminaires, both 400-watt. The new luminaires feature a low-profile modular design, type III optics, a direct arm mount, and 6 light bars totaling 120 light-emitting diodes (LEDs).
The area luminaires include BetaLED's optional integrated occupancy sensors to provide the flexibility of reducing energy consumption when the lot is unoccupied during nighttime hours and raising the illumination levels when occupants are present. Use of the integrated option, which reduces the level of lighting from a 525 mA high output to a 175 mA low output, is estimated to reduce energy costs by approximately 58 percent compared to the previously installed fixtures.
The estimated energy reduction is over 44,000 kWh with savings of $6,000 annually. Another cost benefit is that the LEDs have a projected life of about 150,000 hours of operation (about 15- 20 years of normal use), which means virtually eliminating the $10,000 in previous annual maintenance costs. The calculation assumes that the BetaLED luminaires will operate for 12 hours per day (high mode for five hours and low mode for seven hours) and previous high maintenance costs will be significantly reduced.
The estimated payback period for the installation is three years, based on the current electric rate of $0.14 /kWh, provided by the Public Service of New Hampshire, and maintenance costs incurred at the property for the previously installed fixtures. The energy savings is achieved from a combination of a higher efficacy luminaire solution that provides more precise target illumination compared to the HPS solution.