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- i APPENDIX A. IMPROVED R20 SHORT L AMP

TABLE OF CONTENTS

A.1 INTRODUCTION

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- 1 A.2 INTERNAL DIMENSIONAL COMPATIBILITY OF HALOGEN BURNER CAPSULES

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- 1 A.3 EFFICACY OF IMPROVED DE SIGN OPTIONS

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- 1 APPENDIX A. IMPROVED R20 SHORT L AMP

A.1 INTRODUCTION
This appendix provides detailed information o n the analysis conducted to determine if the efficacy of 100 watt (W) R20 a short (having a maximum overall length (MOL) of 3 and 5/8 (or 3.625) inches) lamps (hereafter “ R20 short lamps”) could be i mproved to meet energy conservation standards. Specifically, the U.S. Department of Energy (DOE) examined the addition of halogen capsules to existing R20 short lamps. Tungsten

- halogen lamps are a specific type of incandescent reflector lamp (IRL) that con tain a small diameter fused quartz envelope filled with a halogen molecule, referred to as a capsule, that surrounds the filament. The use of halogen capsules is known to improve efficacy of IRLs.

Section A.2 of this appendix describes the teardown testing conducted by DOE to determine if halogen capsules are dimensionally compatible with R20 short lamps. S ection A.3 presents results of DOE’s analysis of whether a halogen

- based R20 short lamp would meet energy conservation standards and the special characteristic requirements of the R20 short lamp.

A.2 INTERNA L DIMENSIONAL COMPATIBILITY OF HALOGEN BURNER CAPSULES

DOE received conflicting comments regarding the feasibility of incorporating halogen capsules in R20 short lamps to improve efficacy. DOE performed teardowns to determine the dimensional compatibility of single

- ended and double

- ended halogen capsules with R20 short lamps. The h alogen capsules in tungsten

- halogen lamps are available in two designs: (1) a single

- ended burner that contains a lead wire inside the capsule and (2) a double

- ended burner that f eatures a lead wire outside the capsule. Single

- ended burners are less efficacious than double

- ended due to the presence of the lead wire inside the capsule, which prevents a certain amount of energy from reaching the capsule wall and being reflected back to the capsule filament. Single

- ended burners are also typically smaller in size.

DOE tore down two 100W R20 short lamp models, one from each of the two known manufacturers of R20 short lamps. DOE also tore down one 60W PAR b 16 model containing a single

- en ded halogen burner and one 60W PAR30 short lamp containing a double

- ended halogen burner. DOE gathered internal and external dimensions of the lamp components as well as general design information from these teardowns.

DOE first compared the dimensions of the 100W R20 short lamps to that of the 60W PAR16 model to determine if a single

- ended halogen burner could be utilized in an R20 short lamp. DOE measured the reflector length and the vertical distance from the end of the halogen capsule to the reflector wall of the PAR16 model. DOE then compared these dimensions to the reflector length of the two R20 short lamp models to determine dimensional compatibility. DOE determined that the PAR16 reflector length was 15.3 millimeters (mm) less than the reflector

a “R” denotes a reflector lamp type and “20” denotes diameter in 1/8 inch increments, which translates to 2.5 inches.
b “PAR” denotes a parabolic aluminum reflector lamp type

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- 2 le ngth of the first R20 short lamp model and 15.0 mm less than the reflector length of the second model. The vertical distance from the end of the single

- ended burner halogen capsule to the reflector wall of the PAR16 model was measured to be 6.3 mm. Therefo re, DOE expects that if the single

- ended halogen burner capsule was mounted in an R20 short lamp, there would be an additional 21.3 to 21.6 mm of vertical space between the halogen capsule and reflector wall.

It is evident from the results of the PAR16 a nd R20 short lamp teardowns that a single

ended halogen burner capsule could be incorporated into an R20 short lamp. The PAR16 lamp, which has a considerably smaller reflector length, is able to utilize a single

- ended burner. In addition, DOE was able to v erify this conclusion with the identification of R20 lamps currently available on the market that have a listed MOL of 3.54 inches and contain a single

- ended halogen burner. These R20 halogen lamps have an MOL less than that of R20 short lamps (3.625 inche s)

, which indicate s that there is sufficient space for a single

- ended halogen burner capsule in an R20 short lamp. Therefore, DOE has concluded that the use of a single

- ended halogen burner is dimensionally compatible with an R20 short lamp envelope.

Next , DOE compared the teardown results of the 60W PAR30 short lamp and 100W R20 short lamps to determine if a double

- ended halogen burner capsule could be utilized in an R20 short lamp. The 60W PAR30 and 100W R20 models are described as short lamps because th ey both have a shortened MOL of 3 and 5/8 inches. DOE measured and compared the reflector length and the vertical distance from the end of the halogen capsule to the reflector wall of the 60W PAR30 and R20 short lamp s . DOE determined that the 60W PAR30 sho rt lamp reflector length was 2.9 mm less than the reflector length of the first R20 short lamp model and 2.6 mm less than the reflector length of the second R20 short lamp model. The vertical distance from the end of the double

- ended halogen burner capsule to the reflector wall of the PAR30 short lamp model was measured to be 4.6 mm. As a result of the component dimensions, DOE expects that if the double

- ended halogen burner capsule was mounted in an R20 short lamp, there would be an additional 7.2 to 7.5 m m of vertical space between the halogen capsule and reflector wall.

The PAR30 short lamp and R20 short lamp teardowns indicate that a double

- ended halogen burner capsule could be utilized in an R20 short lamp. The PAR30 short lamp reflector length was sli ghtly less than that of the R20 short lamp which suggests there is sufficient space for a double

- ended burner. Because the PAR30 short lamp is able to accommodate the double

ended burner, DOE has concluded that a double

- ended burner is also dimensionally c ompatible with an R20 short lamp.

Through the results of the independent teardown testing discussed in this section , DOE was able to confirm that single

- ended and double

- ended halogen burners that are the appropriate size for R20 short lamps exist.

A.3 EFFIC ACY OF IMPROVED DESIGN OPTIONS
After establishing that single

- ended and double

- ended halogen burners are dimensionally compatible with R20 short lamps, DOE next performed testing to determine the potential improvement in efficacy for R20 short lamps through the use of these technologies. DOE did not identify any commercially available R20 short lamps for use in spa applications with a single

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- 3 ended or double

- ended halogen burner. Therefore, to determine the improvement in efficacy of a 100W R20 short l amp containing a halogen burner, DOE developed theoretical model s by scaling from a commercially available product . DOE developed 75W modeled R20 lamps with halogen technology, expecting manufacturers to reduce the wattage when developing more efficacious lamps.

DOE tested a 120V

, 45W halogen R20 lamp that contained a single

- ended burner to determine the lamp’s performance. DOE then used the measured lumen output and wattage with equations from the Illuminating Engineering Society of North America (IESNA) Lighting Handbook to scale to a higher wattage halogen R20 lamp with a single

- ended burner. DOE scaled the 45W lamp to determine the lumen output of a 75W R20 halogen lamp assuming constant voltage and lifetime. The equations that DOE used from th e IESNA Lighting Handbook are as follows:

d volts VOLTS
LIFE

life ) ( **=** Eq. A

. 1

k VOLTS

volts
LUMENS

lumens ) ( **=** Eq. A

. 2

n VOLTS

volts
WATTS

watts ) ( **=** Eq. A

. 3

DOE determined through this scaling calculation that the efficacy of an R20 short lamp improves with the use of a single

- ended halogen burner. The efficacy of the 100W R20 short lamp was measured to be 8.5 lumens per watt (lm/W), while t he theoretical efficacy of the 75W modeled halogen R20 with single

- ended burner was calculated to be 10.3 lm/W. However, the efficacy would not increase enough to allow the lamp to meet the current energy conservation standard of 12.5 lm/W set forth by the Energy Indepe ndence and Security Act of 2007 (EISA 2007) or the standard of 16.0 lm/W prescribed in the “ Energy Conservation Standards and Test Procedures for General Service Fluorescent Lamps and Incandescent Reflector Lamps ” final rule (hereafter “2009 Lamps Rule”) that becomes effective in July 2012.

DOE utilized a similar scaling process to determine if the incorporation of a double

ended halogen burner would successfully increase the efficacy of an R20 short lamp by a

s ufficient amount to meet the EISA 2007 standards or the 2009 Lamps Rule standards. DOE first identified a commercially available 120V

, 60W PAR30 short lamp that contained a double

ended burner and verified through teardown testing that the burner was dimen sionally compatible with an R20 short lamp (see section A.2 ). DOE acknowledges that a lamp’s reflector efficiency, which affects the overall lamp efficacy, is depe ndent on the envelope shape. During past reflector efficiency testing, DOE determined the average reflector efficiency of R20

- shaped lamps to be 62.2 percent. Therefore, in order to more accurately determine the efficacy of an R20 short lamp with a double

- ended halogen burner, DOE performed efficacy testing of the PAR30 short lamp’s halogen capsule with the PAR

- shaped reflector removed. DOE then applied theA

- 4 reflector efficiency value of 62.2 percent to the halogen capsule efficacy to determine the combined efficacy of the double

- ended burner capsule with the R

- shaped reflector.

DOE used Eq. A

. 1

, Eq. A

. 2 , and Eq. A

. 3 to scale the theoretical 60W R20 halogen lamp
to a 75W lamp. DOE calculated the lumen output of a 75W R20 halogen lamp assuming con stant voltage and lifetime. DOE determined through the scaling calculation that the efficacy of an R20 short lamp improves with the use of a double

- ended halogen burner. The efficacy of the 100W R20 was measured to be 8.5 lm/W, while the efficacy of the 75 W modeled R20 halogen lamp was calculated to be 13.8 lm/W. DOE determined that the use of a double

- ended halogen burner would likely enable the 75W modeled R20 halogen lamp to meet the EISA 2007 standard of 12.5 lm/W; however, the efficacy would not increa se enough to meet the 2009 Lamps Rule standard of 16.0 lm/W.

DOE also concluded through testing and research that R

- shaped reflector lamps are the least efficacious reflector lamps due to their blown glass shape. R

- shaped reflector lamps also contain a r eflective coating that is made by vaporizing the reflector inside the envelope and is, therefore, not guaranteed to be uniform. In comparison, PAR

- shaped reflector lamps contain an aluminum metal reflector as well as a plastic lens over the aperture of the lamp that can be optimized to control light output. This inherit deficiency of R

- shaped reflectors affects the ability to improve the efficacy of R20 short lamps despite the use of a halogen capsule.

In addition to testing, DOE interviewed manufacturers of R20 short lamps to gather supporting information on the comments DOE received that suggest improving the efficacy of R20 short lamps was not possible. DOE was particularly interested in receiving manufacturer feedback on whether single

- ended and double

- ended burners had been successfully integrated into R20 short lamps. DOE confirmed during interviews that manufacturers had attempted to improve the efficacy of R20 short lamps through the use of halogen capsules. The information shared by manufacturers s upports DOE’s findings that while some halogen capsules are dimensionally compatible with the R20 short lamp envelope, the use of halogen capsules does not improve the efficacy enough to meet the 2009 Lamps Rule standards.

DOE considered whether the 75W m odeled R20 halogen lamps successfully replicated the necessary performance specifications of lumen output and beam spread using the theoretical calculations previously described in this section. DOE determined that the 75W modeled R20 halogen lamp with single

- ended burner would have a lumen output of approximately 769 lumens, which is within the established R20 short lamp range of 637 to 1,022 lumens. DOE also determined that the 75W modeled R20 halogen lamp with double

- ended burned would have a lumen output of approximately 1,036 lumens, which is slightly higher, but comparable to the established range. DOE anticipates that the beam angle could be affected by the use of a halogen capsule; however, prototypes would need to be constructed and tes ted in order to determine to what degree. Because DOE determined that the 75W modeled R20 halogen lamp was not a viable option due to insufficient efficacy improvement, DOE did not conduct prototype testing to verify the effect on beam angle.