Xenon Lighting: Technology Evaluation & TestingDue to the potential use of xenon lamps in outdoor...

PG&E’s Emerging Technologies Program ET12PGE1262

Xenon Lighting:

Technology Evaluation & Testing

ET Project Number: ET12PGE1262

Project Manager: Philip Broaddus Pacific Gas and Electric Company Prepared By: California Lighting Technology Center University of California, Davis 633 Pena Drive Davis, California

Issued: June 2015

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ACKNOWLEDGEMENTS

Pacific Gas and Electric Company’s Emerging Technologies Program is responsible for this project. It was developed as part of Pacific Gas and Electric Company’s Emerging Technology – Technical Assessment program under internal project number ET12PGE1262. The California Lighting Technology Center conducted this technology evaluation for Pacific Gas and Electric Company with overall guidance and management from Philip Broaddus. For more information on this project, contact [email protected].

LEGAL NOTICE

This report was prepared for Pacific Gas and Electric Company for use by its employees and agents. Neither Pacific Gas and Electric Company nor any of its employees and agents:

(1) makes any written or oral warranty, expressed or implied, including, but not limited to those concerning merchantability or fitness for a particular purpose;

(2) assumes any legal liability or responsibility for the accuracy, completeness, or usefulness of any information, apparatus, product, process, method, or policy contained herein; or

(3) represents that its use would not infringe any privately owned rights, including, but not limited to, patents, trademarks, or copyrights.

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ABBREVIATIONS AND ACRONYMS

CCT Correlated Color Temperature

CIE International Commission on Illumination

CLTC California Lighting Technology Center

CMH Ceramic Metal Halide

CRI Color Rendering Index

DLC DesignLights Consortium

HPS High Pressure Sodium

IES Illuminating Engineering Society

LED Light Emitting Diode

LM Lighting Memorandum

LPW Lumen per Watt

MH Metal Halide

nm nanometers

PGE Pacific Gas and Electric Company

TM Technical Memorandum

SSL Solid-state Lighting

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FIGURES

Figure 1 – Two meter integrating sphere ......................................... 7

Figure 2 – CIE color space with black body locus .............................. 8

Figure 3 – Color rendering index (CRI Ra) color samples.................... 9

Figure 4 – CIE 1960 with blackbody locus and vectors indicating

positive and negative Duv. ........................................... 9

Figure 5 - CCT quadrangles for the Energy Star LED specification ..... 10

Figure 6 - Goniophotometer (Type C) ........................................... 11

Figure 7 - Xenon Testing Set Up, Side View ................................... 12

Figure 8 – Xenon Testing Set Up, Top View ................................... 12

Figure 9 – Light Sensor Location, Bare lamp .................................. 13

Figure 10 – Light Sensor Location, Fixture ..................................... 14

Figure 11 –Thermocouple Attachment Locations ............................. 14

Figure 12 – Luminous Flux for Manufacturer 2 - Bare Lamps

(Manufacturer Specifications in Dashed Lines) ............... 18

Figure 13 – Luminous Flux for Manufacturer 2 – In Fixtures

(Manufacturer Specifications in Dashed Lines) ............... 18

Figure 14 - CCT for Manufacturer 2 (Manufacturer Specifications in

Dashed Lines) ............................................................ 19

Figure 15– Duv for Manufacturer 2 ............................................... 20

Figure 16 – CRI for Manufacturer 2 (Manufacturer Specifications in

Dashed Lines) ............................................................ 20

Figure 17 - Bare Lamp Distribution Plot for Initial Light Output ........ 21

Figure 18 - Fixture Distribution Plot for Initial Light Output .............. 21

Figure 19 – Light Level during Life Testing for Manufacturer 2 -

Bare Lamps ............................................................... 23

Figure 20 – Light Level during Life Testing for Manufacturer 2 -

Fixtures .................................................................... 24

Figure 21 - Ballast Temperatures for Manufacturer 2 – Bare Lamps .. 25

Figure 22 – Ballast and Chamber Temperatures for Manufacturer 2

- Fixture .................................................................... 26

http://cltc-sharepoint/sites/brightwork/DEV/CLTCPO/Xenon/Project%20Documents/PGE%20Xenon%20Lighting%20ET%20Final%20Report.docx#_Toc423365424

http://cltc-sharepoint/sites/brightwork/DEV/CLTCPO/Xenon/Project%20Documents/PGE%20Xenon%20Lighting%20ET%20Final%20Report.docx#_Toc423365424

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TABLES

Table 1 – Average Luminaire Efficacy for Outdoor Lighting

Technologies ............................................................... 1

Table 2 – Average Luminaire CRI for Outdoor Lighting Technologies ... 1

Table 3 – Average Luminaire CCT for Outdoor Lighting

Technologies ............................................................... 2

Table 4 – Average Lamp Life for Outdoor Lighting Technologies ......... 2

Table 5 - Manufacturer Literature Performance Claims And Tested

Performance - Manufacturer 2 ....................................... 2

Table 6 - Performance specifications for the DesignLights

Consortium benchmark ................................................. 3

Table 7 – Installed Baseline for Outdoor Lighting Technologies in

the United States ........................................................ 5

Table 8 – Chromaticity coordinates defining CCT quadrangles for

Energy Star LED specification ..................................... 10

Table 9 – Average Luminaire Efficacy for Outdoor Lighting

Technologies ............................................................. 15

Table 10 – Average Luminaire CRI for Outdoor Lighting

Technologies ............................................................. 15

Table 11 – Average Luminaire CCT for Outdoor Lighting

Technologies ............................................................. 16

Table 12 – Average Lamp Life for Outdoor Lighting Technologies ..... 16

Table 13 - Manufacturer Performance Claims ................................. 17

Table 14 - Manufacturer Literature Performance CLAIMS AND

Tested Performance - Manufacturer 2 ........................... 27

Table 15 - Performance specifications for the DesignLights

Consortium benchmark ............................................... 27

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CONTENTS

ABBREVIATIONS AND ACRONYMS _____________________________________________ II

FIGURES _______________________________________________________________ III

TABLES ________________________________________________________________ IV

CONTENTS _____________________________________________________________ V

EXECUTIVE SUMMARY _____________________________________________________ 1

INTRODUCTION __________________________________________________________ 5

BACKGROUND __________________________________________________________ 5

EMERGING TECHNOLOGY __________________________________________________ 6

ASSESSMENT OBJECTIVES __________________________________________________ 6

TECHNICAL APPROACH ___________________________________________________ 7

Market Characterization ........................................................... 7

Photometric Testing ................................................................. 7

Life Testing .......................................................................... 11

Data Analysis ........................................................................ 14

RESULTS_______________________________________________________________ 15

Market Characterization ......................................................... 15

Photometry Results ............................................................... 17

Colorimetric Results ............................................................... 19

Distribution Results ............................................................... 21

Run-Time Results .................................................................. 21

EVALUATIONS __________________________________________________________ 27

RECOMMENDATIONS ____________________________________________________ 29

APPENDIX 1 – EQUIPMENT SPECIFICATION SHEETS _______________________________ 30

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EXECUTIVE SUMMARY

PROJECT GOAL Due to the potential use of xenon lamps in outdoor applications, CLTC in collaboration with PG&E, developed an

evaluation and testing program for xenon technology used in general illumination, outdoor applications. The

research included under this project informs utilities about the performance and reliability of xenon lamps in these

applications as compared to Light Emitting Diodes (LED), induction or other appropriate parking and area lighting

solutions. This program identified available xenon products, evaluated manufacturers’ product literature to estimate

their performance against other outdoor luminaires, and quantified photometric and electrical performance of

representative xenon products in a laboratory setting using industry-accepted test methods. Information and results

may be used to determine the viability of xenon technology for current or future incentive programs.

PROJECT DESCRIPTION This evaluation project consists of a commercially available outdoor lighting product market assessment, a

comparison of manufacturer claims regarding these products, and a laboratory evaluation of representative xenon

products marketed for use in the outdoor sector. Laboratory test results characterize xenon product performance with

respect to photometric and electrical properties over the course of 11,000 hours of run-time.

PROJECT FINDINGS Manufacturer’s claimed performance data was collected for representative examples of existing outdoor

technologies to inform a recommended minimum performance specification for general illumination, outdoor

applications. For each lighting technology, products were compared based on equivalent initial delivered light

output and binned into output ranges. The average of manufacturer’s claimed performance by output range is

provided in Table 1 – Table 4.

TABLE 1 – AVERAGE LUMINAIRE EFFICACY FOR OUTDOOR LIGHTING TECHNOLOGIES

Light Output (lm) Average Luminaire Efficacy (lm/W)

HPS Induction LED MH Ceramic Xenon

0 – 5,000 - 46.4 63.7 81.1 67.7

5,001 – 10,000 57.6 47.6 74.0 74.4 69.7

10,001 – 15,000 65.5 93.1 74.4 76.0 66.7

15,001 – 20,000 64.6 - 75.6 - 66.7

20,001 – 25,000 - - 71.6 75.6 -

TABLE 2 – AVERAGE LUMINAIRE CRI FOR OUTDOOR LIGHTING TECHNOLOGIES

Light Output (lm) Average CRI

HPS Induction LED MH Ceramic Xenon

0 – 5,000 - 83 70 70 85

5,001 – 10,000 21 85 73 70 78

10,001 – 15,000 21 80 73 70 85

15,001 – 20,000 21 - - 90 85

20,001 – 25,000 - - 70 90 -

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TABLE 3 – AVERAGE LUMINAIRE CCT FOR OUTDOOR LIGHTING TECHNOLOGIES

Light Output (lm) Average CCT (Kelvin)

HPS Induction LED MH Ceramic xenon

0 – 5,000 - 5,000 3,900 2,800 4,500

5,001 – 10,000 2,100 5,000 4,500 2,800 4,400

10,001 – 15,000 2,100 5,000 4,500 2,800 4,300

15,001 – 20,000 2,100 - - 3,000 4,300

20,001 – 25,000 - - 5,000 3,000 -

TABLE 4 – AVERAGE LAMP LIFE FOR OUTDOOR LIGHTING TECHNOLOGIES

Light Output (lm) Average Lamp Life (hours)


0 – 5,000 - 100,000 65,000 30,000 25,000

5,001 – 10,000 24,000 100,000 75,000 30,000 40,000

10,001 – 15,000 24,000 100,000 75,000 30,000 20,000

15,001 – 20,000 24,000 - - 24,000 20,000

20,001 – 25,000 - - 24,000 50,000 -

Following this work, the project team identified two, representative, xenon product manufacturers for inclusion in a

multi-year test program to evaluate their products photometric and electrical performance over time. These

manufacturers are referenced as Manufacturer 1 and Manufacturer 2. Reliability issues encountered during the lamp

burn-in with Manufacturer 1 products disqualified it from the long-term testing program. After the initial burn-in

period, testing included 16 test samples from Manufacturer 2. Seven of the samples were tested in shoe-box fixtures.

Nine samples were tested without fixtures and are referenced as ‘bare lamps’. A summary of Manufacturer 2

performance claims, initial test results and 11,000-hour test results are provided in Table 5.

TABLE 5 - MANUFACTURER LITERATURE PERFORMANCE CLAIMS AND TESTED PERFORMANCE - MANUFACTURER 2

Performance Metric

Manufacturer

Specification

Sheet

Tested Initial

Performance (Average)

Tested 11,000 Hour


Bare Lamp Bare Lamp Fixture Bare Lamp Fixture

System Power (W) 67.4 67.7 135.0 69.1 73.5

Luminous Flux – Initial (lm) 6,660 5,176.6 6,275 4,177 2,849

Luminous Flux – Mean (lm) 6,030 - - - -

Efficacy (lm/W) Up to 108 76.5 46.5 60.4 38.8

CRI >80 64.3 65.6 42.4 42.2

CCT 4,300 3,430 3,470 2,853 2,622

Lamp Life (hrs.) 30,000 - - - -

Test results were compared to manufacturer claims and industry standards available at the time of this evaluation.

One industry tool used to benchmark lighting product performance is the DesignLights Consortium (DLC). The

DLC “promotes quality, performance and energy efficient commercial sector lighting solutions through

collaboration among its federal, regional, state, utility, and energy efficiency program members, luminaire

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manufacturers, lighting designers, and other industry stakeholders throughout the US and Canada.” The current

DLC standard for retrofit kits intended for outdoor pole mounted area luminaire applications is included in Table 6.

TABLE 6 - PERFORMANCE SPECIFICATIONS FOR THE DESIGNLIGHTS CONSORTIUM BENCHMARK

DesignLights Consortium Technical Requirements - Retrofit Kits for Outdoor Pole Mounted Area Luminaires 1

Minimum Light Output 1,000 lumens

Zonal Lumen Density 100% light output: 0-90°, <10% light output: 80-90°

Minimum Luminaire Efficacy 70 lumens per Watt

Allowable CCT Less than or equal to 5,700 Kelvin (defined by ANSI C78.377-2011)

Minimum Color Rendering Index 65

L70 Lumen Maintenance 50,000 hours

Warranty 5 years

With respect to luminous output, the xenon product’s baseline and 11,000 hour run-time test results were lower than

manufacturer’s claims. However, the DLC technical specification for outdoor, pole mounted, retrofit kits requires a

minimum light output of 1,000 lumens and tested xenon products met this criteria.

With respect to light distribution, the DLC specification requires 100% of light output to be below 90 degrees with

less than 10% in the 80-90 degree zone. The initial light output distribution plots for representative product samples

showed that the bare lamp retrofit kit produced a non-cutoff distribution. When installed in a shoebox fixture, the

luminaire produced a cutoff distribution with 0.5% of its light output in the 80-90 degree zone. The xenon bare

lamp retrofit kit met the DLC requirements for zonal lumen density when installed in a typical shoebox fixture.

With respect to system efficacy, manufacturer literature claimed an initial system efficacy of 98.8 lumens per watt

(LPW). The average efficacy of the tested bare lamps resulted in an initial value of 76.5 LPW and 60.4 LPW at

11,000 hours of run-time. The average efficacy of products installed in fixtures resulted in an initial value of 46.5

LPW and 38.8 LPW at 11,000 hours of run-time. The DLC technical specification for outdoor, pole mounted

retrofit kits requires an efficacy of 70 LPW. The tested xenon products did not meet this criteria.

For outdoor retrofit kits, manufacturer literature claimed CCT performance of 4,300 K. Tested products did not meet

the manufacturer claims. See Table 5. DLC specifications allow a CCT less than or equal to 5,700 K. Over the

course of the evaluation, the tested products met this criteria with products trending towards warmer CCT over the

11,000 hours of run-time

With respect to color rendering index (CRI), manufacturer literature claimed a CRI of 80 or greater for tested

products. Test results show an average, initial CRI of 65 and a CRI of 42 at 11,000 hours of run-time. The tested

xenon products did not meet manufacturer claims for CRI. DLC specifications require a minimum of 65 CRI. The

tested xenon products did not meet DLC requirements.

Eleven of 18 bare lamps tested failed prior to the 11,000 hours of run-time. Leveraging industry standards for

similar lighting technologies where “average rated lamp life is defined as that time after which 50% of a large group

of lamps are still in operation”2, the tested xenon products did not meet manufacturer claims of a 30,000 hour

lifetime.

1 DesignLights Consortium. Technical Requirements Table v2.1. 2015. 2 Illuminating Engineering Society. The Lighting Handbook. Tenth Edition. Page 7.45. 2011.

https://www.designlights.org/content/QPL/ProductSubmit/CategorySpecifications

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For xenon lamps installed and tested in fixtures, three of seven fixtures were operational at 11,000 hours. The test

product’s configuration included redundant arc tubes. Of the total arc tubes, 3 of 14 arc tubes were operational.

Leveraging industry standards for similar lighting technologies where “average rated lamp life is defined as that

time after which 50% of a large group of lamps are still in operation”, the tested xenon product did not meet

manufacturer claims of a 30,000 hour lifetime when installed in typical shoebox fixtures.

At the time of this evaluation, the tested xenon products did not meet manufacturer claims for light output, luminaire

efficacy, CCT, CRI or lifetime.

PROJECT RECOMMENDATIONS The performance testing conducted as part of this xenon evaluation provides context regarding expected product

operation. Stakeholders considering development of incentive programs for xenon products used in the commercial

outdoor lighting sector should consider this data. The representative xenon products tested did not meet

manufacturer performance claims for light output, luminaire efficacy, CCT, CRI or lifetime. For best-practice

lighting design, each product should be evaluated individually to verify its reliability and performance before

specifying its use. In addition, it is recommended that industry accepted standards be leveraged as the performance

specification for xenon moving forward. One such standard, provided by the DLC, is available for LED outdoor,

pole mounted, retrofit kits.

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INTRODUCTION Due to the potential use of xenon lamps in outdoor applications, CLTC in collaboration with PG&E, developed an

evaluation and testing program for xenon technology used in general illumination, outdoor applications. The

research included under this project informs utilities about the performance and reliability of xenon lamps in these

applications as compared to Light Emitting Diodes (LED), induction or other appropriate parking and area lighting

solutions. This program identified available xenon products, evaluated manufacturers’ product literature to estimate

their performance against other outdoor luminaires, and quantified photometric and electrical performance of

representative xenon products in a laboratory setting using industry-accepted test methods. Information and results

may be used to determine the viability of xenon technology for current or future incentive programs.

BACKGROUND In a properly designed lighting system, application-appropriate illumination levels are provided without producing

extraneous light or glare. Luminaire pole spacing and distribution types are chosen to optimize the coefficient of

utilization or maximize the use of light where it is needed. Light pollution and light trespass, such as street lights

shining into neighboring windows, is mitigated with use of appropriate optical designs. As of 2010, high pressure

sodium (HPS) and metal halide lamps with magnetic ballasts were identified as the most common types of

luminaires used in outdoor applications. Potential replacement technologies include induction, LED, ceramic metal

halide, and xenon.

TABLE 7 – INSTALLED BASELINE FOR OUTDOOR LIGHTING TECHNOLOGIES IN THE UNITED STATES 3

Source

Type

Installed

Base

Market

Share

Incandescent 17,814,000 10%

Halogen 4,021,000 2%

Compact fluorescent 12,053,000 7%

Linear fluorescent 29,124,000 16%

Mercury vapor 4,177,000 2%

Metal halide 29,514,000 17%

High pressure sodium 57,941,000 32%

Low pressure sodium 1,455,000 1%

LED 19,219,000 11%

Miscellaneous 3,056,000 2%

3 Navigant Consulting, Inc., Building Technologies Program, U.S. Department of Energy. 2010 U.S. lighting market characterization.

January 2012.

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EMERGING TECHNOLOGY Xenon products marketed for outdoor, general illumination applications consist predominantly of retrofit kits that

include a xenon lamp and ballast. Interviews with lighting distributors established that the most common xenon

retrofit kits were targeted at shoebox-style fixtures. Therefore, the shoebox-style retrofit solution was chosen as the

representative xenon product for this evaluation.

Performance characteristics of commercially available luminaires for general outdoor applications were reviewed to

characterize this market. The project team reviewed an example of each lighting solution listed in Table 7 and for a

range of light output groups. Performance metrics collected include power, light output, CCT, CRI, and lifetime.

Power (W) – The maximum amount of power required to operate the luminaire (measured in watts).

Light Output (lm) – The amount of visible light output by a light source independent of direction, and

weighted to the sensitivity of human vision (measured in lumens).

Correlated Color Temperature (CCT), Duv – CCT correlates a luminaire’s color to the color of a black

body radiator at a given temperature and is measured in degrees kelvin (K). A tight tolerance on the color

temperature and Duv of luminaires ensures that luminaires in close spatial proximity appear to be the same

color.

Color Rendering Index – CRI compares a light source’s rendering of a set of pastel colors with that of a

blackbody radiator of the same CCT. CRI (Ra) is the most widely used standard to establish the ability of a

luminaires to render colors correctly.

Lifetime – The lifetime of each lamp, expressed in hours. For metal halide and xenon this was defined as

the number of hours that on average 50% of lamps would fail by (67% for high pressure sodium). For LED

and induction lamps, this is the point at which lumen output has reduced to 70% of its initial rated output

(L70).

These performance metrics were used to compare xenon luminaires with traditional outdoor luminaires and other

potential replacement technologies. These metrics form the foundation of the minimum performance specification

recommended for xenon products used in general illumination, outdoor applications.

ASSESSMENT OBJECTIVES The assessment objective of the xenon technology evaluation program was to characterize xenon product

performance with respect to multiple performance metrics and compare that performance to other outdoor lighting

technologies. Performance metrics were collected from manufacturer’s product literature and used as part of the

initial market characterization discussed below. The project team also conducted a laboratory evaluation of selected

xenon products to verify manufacturer’s claims and document actual product performance with respect to industry

standard technical requirements for alternative replacement technologies. Recommendations based on evaluation

results may be used to determine the xenon’s viability for current or future rebate and incentive programs.

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TECHNICAL APPROACH This evaluation program’s technical approach included a market characterization and photometric testing of selected

xenon products conducted according to industry-standard test procedures.

MARKET CHARACTERIZATION

Manufacturer performance data was collected for representative examples of traditional and emerging technologies.

Xenon manufacturers identified during the market characterization were contacted and interviews conducted to

understand how they intended xenon products to be used in outdoor applications. Products commercially available

in the United States were determined appropriate for inclusion in the evaluation.

PHOTOMETRIC TESTING

Selected products underwent photometric testing to verify initial and long-term performance. For photometric

testing, luminaires and lamps were mounted on brackets optimized for their form factor. Integrating sphere and

goniophotometer tests were completed to characterize the product’s baseline performance. Additional integrating

sphere tests were completed after each 1,000 hours of run-time to characterize performance over time.

INTEGRATING SPHERE Metrics related to light, without respect to angle, such as light output, correlated color temperature (CCT), CRI, and

chromaticity, were measured in an integrating sphere, shown in Figure 1. The sphere’s interior coating allows for

light to be distributed diffusely and evenly over sphere’s interior surface. A shielded spectrometer on the sphere’s

surface was used to collect spectral power distribution (SPD) measurements. SPD provides radiance (power in

Watts) per wavelength (nm). The spectrometer used in this testing is capable of measuring light with wavelengths

between 360 nanometers (nm) and 1,000 nm.

FIGURE 1 – TWO METER INTEGRATING SPHERE

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The procedures for collecting integrating sphere measurements are detailed in the Illuminating Engineering

Society’s (IES) Lighting Memorandums (LM), LM-51 Electrical and Photometric Measurements of HID Lamps4

and LM-79 Photometric Measurements for Solid State lighting5. Spectrometer software converts the captured SPD

data into metrics of interest such as total light output (lumens), color correlated temperature (CCT), color rendering

index (CRI) and chromaticity coordinates. A source’s total light output is determined by summing the photopically

corrected SPD over the visible light spectrum.

CCT correlates a lamp’s color to the color of a black body radiator at a given temperature and is measured in Kelvin

(K). The spectrum of color visible to the human eye is defined by the International Commission on Illumination

(CIE) color space. Figure 2 illustrates the blackbody locus, a line representing the spectrum of color that is radiated

from an ideal black body radiator.

FIGURE 2 – CIE COLOR SPACE WITH BLACK BODY LOCUS

4 LM51 Electrical and Photometric Measurements of HID. Illumination Engineering Society of North America. 2000. 5 LM79 Photometric Measurements for Solid State Lighting. Illumination Engineering Society of North America. 2008.

9


CRI compares a light source’s rendering of a set of standard colors (Figure 3) with that of a blackbody radiator of

the same CCT. Average CRI (Ra) is represented as a single number from 0-100. Ra is based on an eight standard

color samples. Six additional color pallets have been added to augment the Ra metric.

FIGURE 3 – COLOR RENDERING INDEX (CRI RA) COLOR SAMPLES

Duv is defined as the closest distance of the tested sample from the Plankian locus in the color space. Positive

signed Duv is above the Plankian locus and negative signed Duv is below the Plankian locus.6 (Figure 4)

FIGURE 4 – CIE 1960 WITH BLACKBODY LOCUS AND VECTORS INDICATING POSITIVE AND NEGATIVE DUV. 7

6 American National Standard: Specifications for the Chromaticity of Solid State Lighting Products.

ANSI C78.377-2011. 7 Thompson, M. Defining quality of Light. Voices for SSL Efficiency 2011 – DOE SSL market introduction workshop.

http://apps1.eere.energy.gov/buildings/publications/pdfs/ssl/thompson_quality_sslmiw2011.pdf.

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Chromaticity quadrangle specifications are provided in Figure 5, showing the quadrangles for the 7-step MacAdam

ellipses. MacAdam ellipses represent regions on the chromaticity chart where a portion of the population cannot

differentiate color. MacAdam steps refer to the size of the tolerance range as defined by the allowable deviation

from the target CCT. Table 3 provides the color space coordinates that define the MacAdam ellipse equivalent

quadrangles in Figure 5.

FIGURE 5 - CCT QUADRANGLES FOR THE ENERGY STAR LED SPECIFICATION8

TABLE 8 – CHROMATICITY COORDINATES DEFINING CCT QUADRANGLES FOR ENERGY STAR LED SPECIFICATION 9

8 ANSI C78.377-2011. Specifications for the Chromaticity of Solid State Lighting Products. 2011.

9 ANSI C78.377-2011. Specifications for the Chromaticity of Solid State Lighting Products. 2011.

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GONIOPHOTOMETER – TYPE C Angular light distribution is measured using a goniophotometer such as the one shown in Figure 6. For this

evaluation, a C-type goniophotometer was used. In a C-type goniophotometer, light sources are translationally fixed

in a central location and a mirror moves around the light source. The source is rotated around its vertical axis to

collect light intensity data for a spatial characterization of its light output. The light sensor used to collect data is a

photopically corrected cosine photosensor. The procedures for taking angular distribution measurements are detailed

in IES LM-51 Electrical and Photometric Measurements of HID Lamps and LM-79 Photometric Measurements for

Solid State Lighting. The output from the goniophotometer provides luminous intensity (candelas) as a function of

user-defined angular resolution in the vertical and horizontal planes.

FIGURE 6 - GONIOPHOTOMETER (TYPE C)

LIFE TESTING

Run-time data used for life testing is collected from the lamp or luminaire mounted in a test rack that allows for the

regulation of thermal conditions. Lamps are controlled through a central switch that turns all units on or off.

Photosensors are placed next to each lamp or fixture to determine how many hours each has been on and measure

relative light depreciation over time. A data acquisition and control system records temperature and voltage data,

and controls the on/off switch. Figures 7 and 8 show the laboratory run-time test chamber including the fixture

mounting apparatus and test instrumentation used in this program.

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FIGURE 7 - XENON TESTING SET UP, SIDE VIEW

FIGURE 8 – XENON TESTING SET UP, TOP VIEW

The data acquisition system was centrally located with data cables connected to sensors at each product sample. The

system consists of a desktop computer running LabVIEW software connected to a data acquisition chassis that holds

modules for communication with voltage and temperature sensors. For each light source, one voltage and two

thermocouple lead wires were connected from the chassis to the thermocouples and light sensor/amplifier. The

thermocouples were attached to the ballast at the temperature measurement point and at the base of the light source.

The light sensor was placed in a tube aimed at the lamp to restrict stray light contributions. A detailed equipment

list for the run-time testing apparatus is provided below.

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Data acquisition

National instruments compact DAQ chassis (cDAQ-9178)

o (32) Channel voltage module (NI9205)

o (6) 16-channel thermocouple modules (NI9940)

Desktop computer running LabVIEW software by National Instruments and Windows 7 operating

system

Sensors

Light

o (32) Photometric cosine corrected photo sensors LI-COR (LI-210SA)

o (32) Trans conductance LI-COR amplifiers EME Systems UTA

Temperature

o (67) 40-gauge, K-type thermocouples Omega 5TC-TT-K

Main line voltage

o Eagle 120 power analyzer

Control

Power

o Digital out (NI 6008)

o Digitally controlled multi-pole single throw relay

Light level and component temperature data were recorded at a one minute resolution. Light level data allowed for

verification of the number of hours run, while component temperature data allowed for safety monitoring and acted

as a diagnostic tool for system failure analysis. Figure 9 and Figure 10 show the location of the light sensors for the

bare lamps and fixtures. Figure 11 shows the thermocouple attachment locations with two on the center of the lamp

ballasts and a third on the housing to illustrate chamber temperature.

Time series data collected over the course of the evaluation allowed for the validation of manufacturer’s claims and

assisted with reliability assessments. Light level and component temperature trends for both bare lamps and lamps

operating in fixtures is provided in the results. Data was reduced to remove time periods when the lights were

intentionally turned off, including two daily, hour-long, off periods and lab maintenance periods.

FIGURE 9 – LIGHT SENSOR LOCATION, BARE LAMP

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FIGURE 10 – LIGHT SENSOR LOCATION, FIXTURE

FIGURE 11 –THERMOCOUPLE ATTACHMENT LOCATIONS

DATA ANALYSIS Manufacturer’s literature, industry standards and product test results collected over the course of the program are

compiled through 11,000 hours of run-time. Trend plots for product performance are provided to compare to

industry standards and manufacturer claims.

15


RESULTS Over the course of the xenon evaluation, product performance data was gathered according to the technical approach

outlined in this report. The results from the market characterization, photometric testing and life testing are

provided in this section.

MARKET CHARACTERIZATION Manufacturer’s claimed performance data was collected for representative examples of existing outdoor

technologies to inform a recommended minimum performance specification for general illumination, outdoor

applications. For each lighting technology, products were compared based on equivalent initial delivered light

output and binned into output ranges.

Within each light output range, the average manufacturer claimed luminaire efficacy is provided in Table 9.

TABLE 9 – AVERAGE LUMINAIRE EFFICACY FOR OUTDOOR LIGHTING TECHNOLOGIES

Light Output (lm) Average Luminaire Efficacy (lm/W)


0 – 5,000 - 46.4 63.7 81.1 67.7

5,001 – 10,000 57.6 47.6 74.0 74.4 69.7

10,001 – 15,000 65.5 93.1 74.4 76.0 66.7

15,001 – 20,000 64.6 - 75.6 - 66.7

20,001 – 25,000 - - 71.6 75.6 -

Within each light output range, the average manufacturer claimed luminaire CRI is provided in Table 10.

TABLE 10 – AVERAGE LUMINAIRE CRI FOR OUTDOOR LIGHTING TECHNOLOGIES

Light Output (lm) Average CRI


0 – 5,000 - 83 70 70 85

5,001 – 10,000 21 85 73 70 78

10,001 – 15,000 21 80 73 70 85

15,001 – 20,000 21 - - 90 85

20,001 – 25,000 - - 70 90 -

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Within each light output range, the average manufacturer claimed luminaire CCT is provided in Table 11.

TABLE 11 – AVERAGE LUMINAIRE CCT FOR OUTDOOR LIGHTING TECHNOLOGIES

Light Output (lm) Average CCT (Kelvin)


0 – 5,000 - 5,000 3,900 2,800 4,500

5,001 – 10,000 2,100 5,000 4,500 2,800 4,400

10,001 – 15,000 2,100 5,000 4,500 2,800 4,300

15,001 – 20,000 2,100 - - 3,000 4,300

20,001 – 25,000 - - 5,000 3,000 -

Within each light output range, the average manufacturer claimed lamp life is provided in Table 12.

TABLE 12 – AVERAGE LAMP LIFE FOR OUTDOOR LIGHTING TECHNOLOGIES

Light Output (lm) Average Lamp Life (hours)


0 – 5,000 - 100,000 65,000 30,000 25,000

5,001 – 10,000 24,000 100,000 75,000 30,000 40,000

10,001 – 15,000 24,000 100,000 75,000 30,000 20,000

15,001 – 20,000 24,000 - - 24,000 20,000

20,001 – 25,000 - - 24,000 50,000 -

Products from two US manufacturers identified at the time of product selection are included and manufacturers are

referenced as Manufacturer 1 and Manufacturer 2. All commercially available xenon products were intended as a

luminaire retrofit solution with the most common retrofit targeted at a shoebox-style fixture operating with a high

intensity discharge (HID) lamp.

The most common xenon replacement lamp identified during the market characterization was categorized as 100

Watts and operated in a horizontal orientation. Xenon retrofit offerings for lamp sizes greater than 70 Watts are

composed of arrays of smaller, standard-sized xenon lamps. Manufacturer 1 offered lamps in multiples of 35 Watts,

while Manufacturer 2 offered lamps in multiples of 60 Watts. To produce approximately a 100 Watt lamp, xenon

systems consisted of arrays of three-35 Watt lamps totaling 105 Watts, or two-60 Watt lamps totaling 120 Watts.

To account for multi-lamp arrays, and various beam distribution patterns, the array geometry was chosen by

application with options for fixture reflector modifications. Xenon product distributors were given the opportunity to

assist with the retrofit design to make the test units resemble a typical luminaire geometry found in the field. In

addition to testing 100 Watt lamp arrays installed in shoebox-style fixtures, individual bare lamps were tested to

provide performance data comparing arrays and the individual source with respect to photometric performance and

longevity.

The 100 Watt, horizontal product category was selected as the representative case for product testing. Sample size

was limited by product availability and cost. Fourteen fixtures were donated to the project allowing for a test

sample size of seven for each brand. Nine bare lamps from each distributor were included in the testing. This sample

size was selected to maximize the data acquisition channels available on the data acquisition system. The products

selected for evaluation are provided below. Detailed product performance claims are provided in Table 13.

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Test Set-up: Sterner Executive Square 19” shoebox fixture (type 3H reflector)

o (7) Manufacturer 1: 105 Watt xenon lamp array system

o (7) Manufacturer 2: 120 Watt xenon lamp array system

Test Set-up: Bare Lamp

o (9) Manufacturer 1: 35 Watt xenon lamp and ballast system

o (9) Manufacturer 2: 60 Watt xenon lamp and ballast system

TABLE 13 - MANUFACTURER PERFORMANCE CLAIMS

Performance Metric Manufacturer 1 Manufacturer 2

Power (W) 105 60

Luminous Flux - Initial (lm) 10,710 6,660

Luminous Flux - Mean (lm) - 6,030

Efficacy (lm/W) 102 Up to 108

CRI 90 >80

Working Temperature (°C) -40 to 85 -50 to 85

CCT 4,100 - 5,000 4,300

Lamp Life (hrs.) 16,000 - 18,000 30,000

After the initial burn-in period, testing included 16 test samples from Manufacturer 2. Reliability issues encountered

during the lamp burn-in with Manufacturer 1 lamps disqualified the product from the long-term testing program;

however disqualified lamps that survived the initial 100-hour burn in period were run in the test chamber. Light

level and temperature measurements for these products are not included in project reports. Data is available upon

request for limited performance metrics.

PHOTOMETRY RESULTS Light output, or luminous flux, is calculated by integrating a lamp’s SPD weighted for photopic vision. Figure 12

shows measured luminous flux, in lumens, for bare lamps and the manufacturer’s claimed initial and mean output.

Figure 13 shows luminous flux, in lumens, for the units tested in fixtures compared to manufacturer specifications.

Products that did not produce light at 1,000-hour interval testing are marked with an ‘x’ to indicate end of life. Light

level data provided in ‘Run-Time’ results provide specific time of failure. For bare lamps, six of the nine test

samples failed before the 11,000 hour test. For fixtures, four of the seven test samples failed before the 11,000 hour

test.

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FIGURE 12 – LUMINOUS FLUX FOR MANUFACTURER 2 - BARE LAMPS (MANUFACTURER SPECIFICATIONS IN DASHED LINES)

FIGURE 13 – LUMINOUS FLUX FOR MANUFACTURER 2 – IN FIXTURES (MANUFACTURER SPECIFICATIONS IN DASHED LINES)

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COLORIMETRIC RESULTS The SPD data collected by the LabSphere spectrometer and processed with TOCS software is used to derive CCT,

Duv, and CRI. Results are shown in Figure 14. Duv shown in Figure 15, and CRI shown in Figure 16.

FIGURE 14 - CCT FOR MANUFACTURER 2 (MANUFACTURER SPECIFICATIONS IN DASHED LINES)

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FIGURE 15– DUV FOR MANUFACTURER 2

FIGURE 16 – CRI FOR MANUFACTURER 2 (MANUFACTURER SPECIFICATIONS IN DASHED LINES)

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DISTRIBUTION RESULTS Initial light output distribution data is provided in Figure 17 for the bare lamp configuration and Figure 18 for the

fixture configuration. The blue line depicts the vertical plane through the horizontal angle corresponding to the

maximum candela value. The red line depicts the horizontal plane through the vertical angle corresponding to the

maximum candela value.

FIGURE 17 - BARE LAMP DISTRIBUTION PLOT FOR INITIAL LIGHT OUTPUT

FIGURE 18 - FIXTURE DISTRIBUTION PLOT FOR INITIAL LIGHT OUTPUT

RUN-TIME RESULTS Light level and component temperature data was recorded each minute during life testing for all the tested devices.

Light level data allowed for verification of the number of hours run, while component temperature data allowed for

safety monitoring and thermal analysis of the devices. Figure 19 and Figure 20 show the light level trends for the

bare lamps and fixtures, respectively, while Figure 21 and Figure 22 show the component temperature trends for the

bare lamps and fixtures, respectively. Data was reduced to remove time periods when the lights were intentionally

turned off, including the two, hour-long, off periods per day and lab maintenance periods.

22


The reduction in component temperature as shown in Figure 21 and 22 correlates to lamp failures identified in light

level data. Specific drops in ballasts temperatures are noticeable at time of failure providing detail as to which lamp

of the two-lamp system failed.

23


FIGURE 19 – LIGHT LEVEL DURING LIFE TESTING FOR MANUFACTURER 2 - BARE LAMPS

24


FIGURE 20 – LIGHT LEVEL DURING LIFE TESTING FOR MANUFACTURER 2 - FIXTURES

25


FIGURE 21 - BALLAST TEMPERATURES FOR MANUFACTURER 2 – BARE LAMPS

26


FIGURE 22 – BALLAST AND CHAMBER TEMPERATURES FOR MANUFACTURER 2 - FIXTURE

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EVALUATIONS

Xenon product test results were evaluated in comparison to manufacturer claims and industry standards available at

the time of the evaluation. Reliability issues encountered during the lamp burn-in with Manufacturer 1 lamps

disqualified it from the long-term testing program. After the initial burn-in period, testing includes 16 test samples

from Manufacturer 2. A summary of Manufacturer 2 performance claims, initial tested performance and 11,000-

hour tested performance are provided in Table 14.

TABLE 14 - MANUFACTURER LITERATURE PERFORMANCE CLAIMS AND TESTED PERFORMANCE - MANUFACTURER 2

Performance Metric

Manufacturer

Specification

Sheet

Tested Initial


Tested 11,000 Hour


Bare Lamp Bare Lamp Fixture Bare Lamp Fixture

System Power (W) 67.4 67.7 135.0 69.1 73.5

Luminous Flux – Initial (lm) 6,660 5,176.6 6,275 4,177 2,849

Luminous Flux – Mean (lm) 6,030 - - - -

Efficacy (lm/W) Up to 108 76.5 46.5 60.4 38.8

CRI >80 64.3 65.6 42.4 42.2

CCT 4,300 3,430 3,470 2,853 2,622

Lamp Life (hrs.) 30,000 - - - -

One industry tool used to benchmark lighting product performance is the DesignLights Consortium (DLC). The

DLC “promotes quality, performance and energy efficient commercial sector lighting solutions through

collaboration among its federal, regional, state, utility, and energy efficiency program members, luminaire

manufacturers, lighting designers, and other industry stakeholders throughout the US and Canada.”

The current DLC standard for retrofit kits intended for outdoor pole mounted area luminaire applications are

included as reference in Table 15.

TABLE 15 - PERFORMANCE SPECIFICATIONS FOR THE DESIGNLIGHTS CONSORTIUM BENCHMARK

DesignLights Consortium Technical Requirements - Retrofit Kits for Outdoor Pole Mounted Area Luminaires 10

Minimum Light Output 1,000 lumens

Zonal Lumen Density 100% light output: 0-90°, <10% light output: 80-90°

Minimum Luminaire Efficacy 70 lumens per Watt

Allowable CCT Less than or equal to 5,700 Kelvin (defined by ANSI C78.377-2011)

Minimum Color Rendering Index 65

L70 Lumen Maintenance 50,000 hours

Warranty 5 years

10 DesignLights Consortium. Technical Requirements Table v2.1. 2015.

https://www.designlights.org/content/QPL/ProductSubmit/CategorySpecifications

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With respect to luminous output, the xenon product’s baseline and 11,000 hour run-time test results were lower than

manufacturer’s claims. However, the DLC technical specification for outdoor, pole mounted, retrofit kits requires a

minimum light output of 1,000 lumens and tested xenon products met this criteria.

With respect to light distribution, the DLC specification requires 100% of light output to be below 90 degrees with

less than 10% in the 80-90 degree zone. The initial light output distribution plots for representative product samples

showed that the bare lamp retrofit kit produced a non-cutoff distribution. When installed in a shoebox fixture, the

luminaire produced a cutoff distribution with 0.5% of its light output in the 80-90 degree zone. The xenon bare

lamp retrofit kit met the DLC requirements for zonal lumen density when installed in a typical shoebox fixture.

With respect to system efficacy, manufacturer literature claimed an initial system efficacy of 98.8 lumens per watt

(LPW). The average efficacy of the tested bare lamps resulted in an initial value of 76.5 LPW and 60.4 LPW at

11,000 hours of run-time. The average efficacy of products installed in fixtures resulted in an initial value of 46.5

LPW and 38.8 LPW at 11,000 hours of run-time. The DLC technical specification for outdoor, pole mounted

retrofit kits requires an efficacy of 70 LPW. The tested xenon products did not meet this criteria.

For outdoor retrofit kits, manufacturer literature claimed CCT performance of 4,300 K. Tested products did not meet

the manufacturer claims. See Table 5. DLC specifications allow a CCT less than or equal to 5,700 K. Over the

course of the evaluation, the tested products met this criteria with products trending towards warmer CCT over the

11,000 hours of run-time

With respect to CRI, manufacturer literature claimed a CRI of 80 or greater for tested products. Test results show an

average, initial CRI of 65 and a CRI of 42 at 11,000 hours of run-time. The tested xenon products did not meet

manufacturer claims for CRI. DLC specifications require a minimum of 65 CRI. The tested xenon products did not

meet DLC requirements.

Eleven of 18 bare lamps tested failed prior to the 11,000 hours of run-time. Leveraging industry standards for

similar lighting technologies where “average rated lamp life is defined as that time after which 50% of a large group

of lamps are still in operation”11

, the tested xenon products did not meet manufacturer claims of a 30,000 hour

lifetime.

For xenon lamps installed and tested in fixtures, three of seven fixtures were operational at 11,000 hours. The test

product’s configuration included redundant arc tubes. Of the total arc tubes, 3 of 14 arc tubes were operational.

Leveraging industry standards for similar lighting technologies where “average rated lamp life is defined as that

time after which 50% of a large group of lamps are still in operation”, the tested xenon product did not meet

manufacturer claims of a 30,000 hour lifetime when installed in typical shoebox fixtures.

At the time of this evaluation, the tested xenon products did not meet manufacturer claims for light output, luminaire

efficacy, CCT, CRI or lifetime.

11 Illuminating Engineering Society. The Lighting Handbook. Tenth Edition. Page 7.45. 2011.

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RECOMMENDATIONS The performance testing conducted as part of this xenon evaluation provides context regarding expected product

operation. Stakeholders considering development of incentive programs for xenon products used in the commercial

outdoor lighting sector should consider this data. The representative xenon products tested did not meet

manufacturer performance claims for light output, luminaire efficacy, CCT, CRI or lifetime. For best-practice

lighting design, each product should be evaluated individually to verify its reliability and performance before

specifying its use. In addition, it is recommended that industry accepted standards be leveraged as the performance

specification for xenon moving forward. One such standard, provided by the DLC, is available for LED outdoor,

pole mounted, retrofit kits.

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APPENDIX 1 – EQUIPMENT SPECIFICATION SHEETS

Xenon Lighting: Technology Evaluation & TestingDue to the potential use of xenon lamps in outdoor...

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