Lighting : Lighting April 2016 - Vol 36 Issue 2
30 LIGHTING MAGAZINE | April/May 2016 PROCUREMENT PROCESS The Council expressed an early interest in adopting an LED lighting solution, however, with the availability LED floodlights at the time (that could compete in output and upward light spill control), it was doubtful that LED would be a cost-effective solution, given the relatively limited hours of use proposed. Xyst prepared a project brief for supplier-led design and supply that would enable a range of design solutions to be presented to Council at various price points and include a whole-of-life cost analysis. The lighting design brief required compliance with AS 2560.2.3:2007 and FIFA Lighting Guidelines for Football. As is commonplace in sports facilities, operating hours are relatively low when compared to run-times for luminaires such as streetlights. A typical provincial rugby club trains under lights for only about 45 hours a season, so putting an argument for LED, based on energy savings and reduced lamp changes, may be viewed as somewhat disingenuous. However, consultation with the main user, Selwyn United Football Club, showed that an estimated 435 hours of training would occur after civil twilight per annum. While ten times lower than the annual operating hours for typical streetlighting, the proposed operating hours proved critical in the whole-of-life cost evaluation. Five leading suppliers were invited to submit proposals, including HID and LED options, with four HID schemes and two LED schemes being submitted. EVALUATION Evaluation focused on: z Light quality (light technical parameters, CRI, Glare Rating) z Luminaire quality (photometric performance, materials, durability, controls) z Environmental quality (ULOR, spill light, energy efficiency) and z Whole-of-life cost (20 year design life) HID and LED proposals were evaluated separately, with the highest scoring of each category compared against each other. SELECTED SYSTEM Musco’s asymmetrical LED floodlight was selected for the project along with their proprietary Green Light Pole system. The selected luminaire has a system wattage of 630 W producing 67,500 luminaire lumens with an efficacy of 107 lm/W compared with a luminaire efficacy of 77lm/W for a conventional 2 kW metal halide sports floodlight. Table 1 shows the comparison. Given the relatively low lumen output, an additional 52 luminaires were required to provide the required illuminance, however, three fewer poles were needed than for the equivalent HID design. Capital cost for the LED design was approximately 2.3 times higher than the HID equivalent. Concern regarding the lower available flux from the LED solution was mitigated by the manufacturer’s 10-year warranty on maintaining the stated illuminances. The LED luminaire’s higher utilisation factor produced required illuminances with less flux. The whole of life cost saving was calculated at $168,000 over the 20-year project life. This excludes savings on electrical design which were considerable given the LED system requires only 145 amps for start up for the entire system. Table 1: Comparing the selected LED solution with and HID alternative Criterion Selected LED HID metal halide 2 kW System power 630 W 2075 W Luminaire flux 67,500 lm 159,775 lm Efficacy (lm/W) 107 77 Luminaires/Poles needed for compliance 128/20 76/23 Total luminaire flux 8,640,000 lm 12,142,900 lm 2016 Year annual energy cost $6,139 $19,221 Re-lamping cost1 nil $41,268 Note: 1 Cleaning and ballast/driver replacement assumed cost neutral Figure 3. Completed lantern and pole assembly. Figure 4. Pre-wired and pre-aimed cross arms ready for installation.
Lighting February 2016 - Vol 36 Issue 1
Lighting June 2016 - Vol 36 Issue 3