LED Display Case Retrofit ET09SDGE0015

Transcription

1 LED Display Case Retrofit October 1, 2008 Prepared for: Prepared by: Managed by:

2 Preface PROJECT TEAM This project is sponsored by San Diego Gas & Electric s (SDG&E ) Emerging Technologies Program (ETP) with Jerine Ahmed as the project manager. Malcolm Koll of Charles Koll Jewelers (Charles Koll) was the contact and project manager. Emerging Technologies Associates, Inc. (ETA) provided the overall coordination of all parties involved and California Lighting Technology Center (CLTC) prepared the report. DISCLAIMER This report was prepared as an account of work sponsored by San Diego Gas & Electric Company. While this document is believed to contain correct information, neither SDG&E, CLTC, ETA nor Charles Koll, nor any employees, associates, makes any warranty, expressed or implied, or assumes any legal responsibility for the accuracy, completeness, or usefulness of any information, apparatus, product, or process disclosed, or represents that its use would not infringe privately owned rights. References herein to any specific commercial product, process or service by its trade name, trademark, manufacturer, or otherwise, does not necessarily constitute or imply its endorsement, recommendation, or favoring by SDG&E, CLTC, ETA nor Charles Koll, their employees, associates, officers and members. The ideas, views, opinions or findings of authors expressed herein do not necessarily state or reflect those of SDG&E, CLTC, ETA or Charles Koll. Such ideas, views, opinions or findings should not be construed as an endorsement to the exclusion of others that may be suitable. The contents, in whole or part, shall not be used for advertising or product endorsement purposes. Any reference to an external hyperlink does not constitute an endorsement. Although efforts have been made to provide complete and accurate information, the information should always be verified before it is used in any way. ACKNOWLEDGEMENTS SDG&E, CLTC and ETA would like to acknowledge Malcolm Koll of Charles Koll Jewelers for assisting in reviewing the products and installation of the LED fixtures. Without his participation, this assessment project would not have been possible. Page 2

3 Table of Contents Executive Summary... 6 Project Background Introduction Pre Installation Measurements Illuminance and CCT Display Case Temperature Luminance Post-Installation Measurements Illuminance and CCT Display Case Temperature Luminance Analysis Conclusion Page 3

4 Abbreviations and Acronyms CCT Correlated Color Temperature CLTC California Lighting Technology Center ETA Emerging Technologies Associates, Inc. ETP Emerging Technologies Program FC Foot Candle FT Foot/Feet K Kelvin kwh Kilowatt hours LED Light Emitting Diode ROI Return on Investment SDG&E San Diego Gas & Electric W Watts Page 4

5 List of Figures Figure 1: General view of the display case... 8 Figure 2: View of the inside of the display case from the back Figure 3: Illuminance measurement point layout (unit of measure = inch)... 9 Figure 3: Luminance map of the empty case with the ambient lighting on Figure 4: Luminance map of the empty case with the ambient lighting off Figure 5: Luminance map of the full case with the ambient lighting on Figure 6: General view of the display case Figure 7: View of the inside of the display case from the back Figure 8: Illuminance measurement point layout (unit of measure = inch) Figure 9: Luminance map of the empty case with the ambient lighting on Figure 10: Luminance map of the empty case with the ambient lighting off List of Tables Table 1: Illuminance Levels... 6 Table 2: Energy and Demand Savings... 6 Table 3: Estimated Simple Payback... 7 Table 4: Estimated Return on Investment (ROI)... 7 Table 5: Case Illuminance and Correlated Color Temperature Table 6: Display Case Temperature Table 7: Case Illuminance and Correlated Color Temperature Table 8: Display Case Temperature Page 5

6 Executive Summary The linear LED Display Case Retrofit project studied the applicability of LED fixtures in a jewelry display case installation. Pin-based halogen lighting systems were replaced with new linear LED light bar fixtures in 14 jewelry cases located at Charles Koll Jewelers in San Diego. The store operated 14 hours per day, 7 days a week (except Christmas Day), equating to 364 days per year. The linear LED fixtures commercially available were installed to determine if they provided equivalent light quality and intensity. Qualitative and quantitative power and light measurements were taken. Economic costs were calculated. Each lighting systems power requirement was based upon readings obtained by using WattsUp? PRO power analyzer and data logger. The average CCT for the linear LED was 3,600 K and 2,700 K for the pin-based halogen. This resulted in the perception that the LED lighting provided a more robust lighting for the product displayed. The average illuminance level dramatically increased after the installation of the LED fixtures. The maximum uniformity ratio (a ratio of the maximum illuminance to the minimum illuminance) increased, suggesting a less uniform light spread. Table 1: Illuminance Levels Measured Lighting Demonstration Case Illuminance (fc) Avg Max Min Pre-Installation Post-Installation The linear LED fixture drew W/ft, 9.85 W/ft less than pin based halogen fixture which drew 27.1 W/ft. This application had 60 total of linear lighting. A linear LED fixture replaced a pin-based linear halogen lamp fixture. Fixture Type Table 2: Energy and Demand Savings Avg Power (W) Power Savings (W) Annual Energy Savings (kwh) Pin-based Halogen lamp fixture (per ft) Linear LED Light Bar Fixture ( per ft) LED full store (14 display cases 60 ft total) 1, ,012 LED fixtures are expected to require no maintenance over their predicted useful life (50,000 hours or 9.8 years for this application). Considering maintenance and replacement for the pin-based halogen fixtures combined with energy costs ($0.14/kWh), the LED fixture per foot costs $22.97 less per year to operate Page 6

7 than the pin-based Halogens. In a new construction project, installing the LED fixtures in place of the pin based halogen fixtures, the total incremental cost is $75 per foot replaced. In a retrofit project, the cost is $125 per foot replaced. The calculations below DO NOT include labor to install the product since the customer performed the installation. Table 3: Estimated Simple Payback Annual Energy Savings ($) Incremental Cost - New Construction ($) Simple Payback New Construction (Years) Cost Retrofit ($) Simple Payback Retrofit (Years) Pin-based Halogen lamp fixture (per ft) LED (per ft) LED full store (14 display cases 60 ft) , , Table 4: Estimated Return on Investment (ROI) Annual Energy Savings ($) Annual Maintenance Costs ($) Annual Savings ($) Incremental Cost - New Construction ($) Simple Payback New Construction (Years) Cost Retrofit ($) Pin-based Halogen lamp fixture (per ft) Simple Payback Retrofit (Years) LED (per ft) * LED full store (14 display cases 60 ft) ,457 4, , *Based upon 50,000 hour life, annual maintenance cost of LED is calculated using $125/9.8 year life expectancy in this scenario. Using the LED fixtures over the traditional pin based halogen fixtures produces energy savings, yet the simple payback and ROI in both scenarios exceed the desired 2 to 3 year standard used by most companies. When considering the maintenance savings, the ROI is more favorable. However, LED technology is advancing at such a rate that the payback will become more acceptable in the future. This is supported by current trends in LED fixture pricing. There is evidence to support that pricing will be reduced by a factor 10 over the next ten year period. (Steele, Robert V 2006, The Story of a New Light Source Nature Photonics 1, 25-26, /nphoton ). Page 7

8 Project Background 1. INTRODUCTION Lighting and temperature measurements were performed at Charles Koll Jewelers, UTC, to evaluate the performance of a solid-state (LED) lighting system for display cases. The same measurements were performed on December 19, 2007 and on January 10, To determine the power requirements of the lighting systems, a WattsUp? PRO power analyzer and data logger was used. 2. PRE INSTALLATION MEASUREMENTS Existing case lighting was provided by halogen pin-based lamps (Figures 1 and 2). Figure 1: General view of the display case Page 8

9 Figure 2: View of the inside of the display case from the back. To minimize the interference of daylight, the display case used for the measurements was the one placed the furthest away from the windows. The store windows are small and the measurements were performed in the morning (8:30 9:30 am) of a dark overcast day so that the effect of daylight on the measurements is assumed to be insignificant. The display case is 48 long, 24 deep and 9 high. 2.1 Illuminance and CCT The measurement points for illuminance are shown in the picture below. Back 7 a b c d e f Customer Figure 3: Illuminance measurement point layout (unit of measure=inch) Page 9

10 Illuminance and CCT were measured, both with the ambient lighting on and off, with a Minolta CL-200 chroma meter. The results are shown below. Table 5: Case Illuminance and Correlated Color Temperature Case & Ambient Lights Case Lights only Point Illuminance (fc) CCT (K) Illuminance (fc) a 90 3, ,785 b 71 3, ,701 c 75 3, ,680 d 138 3, ,735 e 123 3, ,626 f 122 3, ,646 CCT (K) 2.2 Display Case Temperature Display case temperatures of a congruent display case were measured with a multi-meter with a temperature probe inserted through a slit access point in the rear of the case. Using an alternate case was necessary due to the sample case s construction/setup. The case used for lighting measurements was not fully closed which allowed for convection cooling of the inside of the case and therefore an atypical temperature distribution. The display case lighting had been on for approximately 45 minutes when the measurements were taken. Measurements were taken along the center of the case, on the outside surface of the glass and inside the case approximately an inch below the glass (the measurement on the customer side was directly below the lamp). Results are shown as follows: Table 6: Display Case Temperature Position Temperature ( C) Outside (glass) back center customer Inside (air) Page 10

11 2.3 Luminance Luminance maps were taken with the Photolux system for the empty case (ambient lighting on and off) and for the case with merchandise (ambient lighting on). The camera sensor was placed approximately 54 in above the floor and the camera tilted 30 degrees downward from horizontal. The center of the tripod was placed approximately 14 in away from the center of the edge of the display case on the customer side. Results are shown below. Please note that the scale is not the same in all images. Figure 3: Luminance map of the empty case with the ambient lighting on. Page 11

12 Figure 4: Luminance map of the empty case with the ambient lighting off. Page 12

13 Figure 5: Luminance map of the full case with the ambient lighting on. Page 13

14 3. POST-INSTALLATION MEASUREMENTS These measurements were taken after the installation of the LED system (Figures 6 and 7). Figure 6: General view of the display case Figure 7: View of the inside of the display case from the back. Page 14

15 The display case used for lighting measurements was the same as before the one placed the farthest from the store windows. Measurements were performed approximately at the same time in the morning (8:30 9:30 am). Although the day was sunny, the small windows and the fact that the display case measured was the furthest away from natural light mitigated this effect. The display case is 48 long, 24 deep and 9 high. 3.1 Illuminance and CCT The measurement points for illuminance were the same as for the pre-retrofit measurements and are shown in the picture below. Back 7 a b c d e f Customer Figure 8: Illuminance measurement point layout (unit of measure=inch) Illuminance and CCT were measured, both with the ambient lighting on and off, with a Minolta CL-200 chroma meter. The results are shown below. Page 15

16 Table 7: Case Illuminance and Correlated Color Temperature Case & Ambient Lights Case Lights only Point Illuminance (fc) CCT (K) Illuminance (fc) a 187 3, ,688 b 183 3, ,599 c 162 3, ,576 d 408 3, ,648 e 421 3, ,597 f 397 3, ,592 CCT (K) 3.2 Display Case Temperature The temperature of a similar display case was measured with a multimeter with a temperature probe inserted through a slit in the opening at the back of the case. The same display case that had been used in the pre-retrofit temperature measurements was used here. Similarly to pre-retrofit, temperature measurements were taken after the display case lighting had been on for approximately 45 minutes. The case had been closed for approximately 15 minutes at the time of measurements. Measurements were taken along the center of the case, on the outside surface of the glass and inside the case approximately an inch below the glass. Due to difficulties with sensor placement, customer-side measurements for the inside of the case were taken about 1 inch further (horizontally, away from the customer) from the lamp than in for the pre-retrofit measurement. Results are shown below. Table 8: Display Case Temperature Position Temperature ( C) Outside (glass) back center customer Inside (air) 3.3 Luminance Analysis Luminance maps were taken with the Photolux system for the empty case (ambient lighting on and off) and for the case with merchandise (ambient lighting on). The positions of the equipment were the same as in the pre-retrofit measurements. The camera sensor was placed approximately roughly 54 above the floor and the camera tilted 30 downwards from Page 16

17 horizontal. The center of the tripod was placed approximately 14 away from the center of the edge of the display case on the customer side. Results are shown below. Please note that the scale is not the same in both images. Figure 9: Luminance map of the empty case with the ambient lighting on Page 17

18 Figure 10: Luminance map of the empty case with the ambient lighting off Page 18

19 Conclusion As demonstrated in this project, LED lighting for the jewelry display case lighting has potential for energy savings. Both illuminance and luminance measurements indicate that the LED lighting system provides substantially higher light levels throughout the display case (comparing Table 5 and Table 7. This was also the qualitative assessment of the store staff. The measured color temperature was higher for the LED source, which was in accordance with information supplied by the manufacturer. The temperature of the case was lower when lit by the LED source, making the experience more comfortable to the customer. Although the specific fixtures assessed in this project exceeded typical customer expectations for ROI, the economics of LED fixtures are improving as the technology advances. A utility incentive program can contribute to making LED s a more viable economic solution for the customer. Additionally, bulk purchase commitments typically reduce fixture cost as well. It is recommended that additional assessments be conducted to include linear and small fluorescent lamps, such as the PL13, as the baseline case. This would allow for knowledge to be gained regarding the energy savings potential for the jewelry case market. Page 19