SAN FRANCISCO—As part of its Solid-State Lighting Technology Demonstration GATEWAY Program, the U.S. Department of Energy recently released the results of a Light-Emitting Diode (LED) Retrofit Lamp study conducted at the InterContinental San Francisco. The study was prepared by Pacific Northwest National Laboratory. At the hotel, multi-lamp linear wall-grazing luminaires, mono-point track lights, and recessed adjustable downlights, all using either 20W or 30W halogen MR16 lamps, were retrofitted with 6W LED MR16 replacement lamps by CRS Electronics. In addition, two kinds of recessed downlights using 75W halogen PAR30 lamps were retrofitted with 11W LED PAR30 replacement lamps by Philips Lighting.
The LED MR16 and PAR30 products were installed in several areas of the hotel where luminaires are in continuous operation 24/7, where ceiling heights are 9’ or lower, where dimming was not absolutely essential, and where lower output lamps were desirable or acceptable. These included the first floor registration desk area and elevator lobby, the third and fourth floor conference room emergency-circuit downlights, and the seventh through ninth floor elevator lobbies and the guestroom corridor artwork accent lighting. On the first five floors, all lighting is controlled by a multi-space architectural dimming control system, except for luminaires on emergency circuits which operate at full output at all times. On higher floors, light output is fixed at full output.
LED replacement lamps have the potential of saving substantial energy, but at this point are challenged in their light output and color quality. The lamps for the InterContinental Hotel were selected through a multi-step process for color quality, lumen output and candela distribution, beam appearance, color consistency, flicker, and compatibility with the different transformers in the existing downlights and track heads. The hotel’s strict standards for quality made this a critical process. The selected 6W LED MR16 (avg. 285 lumens, 44 LPW) delivers lumens, color, and candela distribution similar to that of a 20W premium halogen MR16. The 11W LED PAR30 (avg. 440 lumens, 45 LPW) is approximately equivalent to a 40W PAR30 halogen lamp at full output.
Fast Payback on Investment
The capital and energy costs of the retrofit were projected over a three year period. The initial cost of the LED lighting replacements was $19,396 for lamps and group relamping labor. Energy cost, at $0.13 per kWh melded rate, for the retrofitted areas of the hotel is $1,975 annually (16,136 kWh), compared to $6,361 annually (51,975 kWh) for the original halogen lamping. The present value life-cycle cost of the LED installation is $28,294, compared to $48,992 for the halogen lamping. This equates to a payback of 1.1 years, with an adjusted internal rate of return of 39.67 percent.
A complication to the financial and illuminance calculations is that the public areas of the first floor and conference floors were controlled with a large architectural dimming system, and output levels for the halogen lighting had been set to low levels when the system was commissioned. In many cases these levels were lower than the staff or owners would have liked, but they were unaware that the levels could be changed, and the facilities staff was hesitant to reprogram the settings. (Note that throughout the study, comparisons were made to the dimmed halogen setting for these floors.)
The LED replacement lamps yielded mixed results when compared to the illuminance levels produced by the original halogen lamps. The 11W PAR30 LED lamps used at full output in the conference rooms delivered half the illuminance of the original 75W halogen lamps. However, when used on the main floor in areas where halogen lamp circuits were consistently dimmed to lower output, the LED PAR30 lamps delivered higher illuminance levels than the dimmed halogen counterparts. Similarly, the LED MR16 lamps delivered dramatically more light than the dimmed 20W lamps used in the wall-grazing lights behind the registration desk, but in elevator lobbies and guest corridors, the LED MR16 lamps delivered approximately 50 percent less light than the original undimmed 30W halogen lamps. (The dimming system levels were set to full output after the LED lamps were installed because the LED lamps were not dimmable.)
For high-end hospitality applications, illuminance levels and efficacy are not the primary considerations in selecting lighting sources and luminaires. Image, luxury, service, visual interest, and attractive materials and objects are the reason patrons choose this hotel. The hotel operates 24 hours a day and generally, maintenance must be performed at night at high cost. For this reason, reduced relamping frequency is of high value to the hotel to reduce labor costs. The hotel is going beyond the norm by pursuing LEED EBOM (Leadership in Energy and Environmental Design—Existing Buildings Operations and Maintenance) certification, and it prides itself on progressive environmental measures. Consequently, reducing energy use is paramount, but it must be done without sacrificing the aesthetics and functionality of the designed spaces. The LED lamp solutions have received high aesthetic praise and acceptability or they would not have remained in their sockets.
Positive Response to LEDs
The registration desk staff, original lighting designer, hotel owners, facility engineers, security staff, and owners have all provided very positive feedback. The one criticism of the retrofit project is that late at night, the registration desk area space looks and feels “too bright,” as the LED retrofit lamps do not dim well and are set at full output. However, they are pleased with the additional visibility that comes with higher light levels on desk areas where reading and writing tasks are performed, and happy that guest faces are easier to see in person and through security cameras.
This successful installation of LED products did not occur without some disappointments, hiccups and surprises. Dozens of products initially evaluated for use exhibited poor color, flicker, abnormally low output or no output at all, or other unexpected behavior, such as fire-alarm-type strobing when dimmed during the initial install of the retrofit project. In spite of preliminary screening, and an extensive mockup phase, there were still lessons to be learned in the final installation. In summary, LEDs can perform great in retrofit applications if located wisely, but at the moment require additional homework and testing of potential lamps with the actual installed luminaires and control systems.
As of the study’s publication date in November 2010, the replacement lamps had operated for approximately 3,000 hours without incident. Sample lamps are scheduled to be removed from the installation and sent for photometric testing after 1,000 hours, 3,000 hours, 6,000 hours, and 9,000 hours of operation, to document color and light output performance over time. Results from these tests will be added to the study as they become available.
To access the complete Light-Emitting Diode (LED) Retrofit Lamp study, click here.
