APPENDIX 5D. ADVANCED IR COATINGS

TABLE O F CONTENTS

5D.1 I NTRODUCTION

........................................................................................................ 5D­1

5D.2 BACKGROUND

.......................................................................................................... 5D­1

5D.2.1 HIR Technology.......................................................................................... 5D­1

5D.2.2 Silverized reflector coating......................................................................... 5D­2

5D.2.3 Alternative method...................................................................................... 5D­2

5D.3 METHOD

..................................................................................................................... 5D­2

5D.3.1 Capsules

...................................................................................................... 5D­2

5D.3.2 Modifying voltage....................................................................................... 5D­3

5D.3.3 Reflector...................................................................................................... 5D­3

5D.4 RESULTS

..................................................................................................................... 5D­3

5D.4.1 ADLT Burners

............................................................................................ 5D­3

5D.4.2 Reflector Losses.......................................................................................... 5D­4

5D.4.2.1 Commercially Available Lamps

............................................... 5D­4

5D.4.2.2 ADLT Burners

.......................................................................... 5D­5

5D.5 LONG LIFE.................................................................................................................. 5D­5

5D.6 PRICE

........................................................................................................................... 5D­6

5D.7 CONCLUSION............................................................................................................. 5D­7

LIST O F TABLES

Table 5 D.1 Test Results for Burners with Advanced IR Coating............................................ 5D­4

Table 5D.2 Test Results for Burners with Advanced IR Coating Operating at a Reduced

Operating Te mperature

............................................................................... 5D­4

Table 5D.3 Test Results for Commercially Available HIR Lamps......................................... 5D­4

Table 5D.4 Calculated Efficacies for ADLT Burner­Reflector Assemblies

........................... 5D­5

Table 5D.5 Calculated Efficacy for a Long Life (6,000 hours) IRL using an ADLT

Advanced I R burner.................................................................................... 5D­6

5D­iAPPENDIX 5D. ADVANCED IR COATINGS

5D.1 I NTRODUCTION

Trial S tandard Level (TSL) 5 for incandescent reflector lamps (IRL) represents a halogen

infrared reflector (HIR) lamp with the most efficient infrared (IR) glass coatings, reflector

coatings, or filament designs. There currently are commercially available products that meet

TSL 5 by using a silverized reflector coating. One lamp manufacturer currently holds a patent

on this technology which will not expire until after energy conservation standards take effect. In

this chapter the Department of Energy (DOE) presents the results of testing performed on lamps

that utilize a different technology, that is potentially available to all manufacturers, and may

possibly be utilized to manufacture a lamp would comply with TSL 5 without the use of the

proprietary silver technology. In this appendix, DOE investigates not only the resulting lamp

efficacy, when employing the advanced IR coatings, but also investigates manufacturing costs

associated with this technology. Finally, DOE also explores the potential to use this technology

to manufacture high­efficacy, long­life IRL.

5D.2 B ACKGROUND

5D.2.1 H IR Technology

In c hapter 3 of the technical support document (TSD), DOE discusses IR glass coatings

as a possible design option. When containing an IR coating, the same lamp reflects more IR

radiation onto the filament, so if run at the same voltage, the lamp operates at a higher

temperature. This increase in operating temperature increases light output, which in turn

increases efficacy. DOE concluded that this technology met the required screening criteria

outlined in chapter 4 of the TSD and considered it as a design option.

HIR l amps that are commercially available today use IR coatings with alternating layers

of two materials, SiO 2 and a second material of either Ta 2 O 5 or Nb 2 O 5

. Typical layer counts

range from 45 to 75. In contrast, the most efficient HIR lamps have a coating made of three

materials, SiO 2 , Ta 2 O 5 and TiO 2 , the latter in the high ­ index rutile phase. This three material

coating, described as a Hybrid TM by Advanced Lighting Technologies Inc. (ADLT) (hereafter

referred to as advanced IR coating),has an effective IR reflectance significantly higher than that

of the two­material coatings used in the commercially available examples (described in section

5D.3.1 below), resulting in enhanced lumen per watt (lm/W) values.

This a dvanced IR coating is not a developmental product. Developed at ADLT, it has

been in production on 12 Volt, single­ended burners in Europe for more than two years.

However, the lm/W level achieved with this coating on the single­ended configuration is lower

than that realized with the double­ended burners used in the testing described below.

5D­1Neither the burner nor the coating provided to DOE requires additional development.

Both are separately in production at present, not patented, and available to all lamp

manufacturers. The additional layers lead to a slight increase in manufacturing time compared to

the coatings currently in use in the market place.

5D.2.2 S ilverized reflector coating

Though a luminum is most prevalent as a reflector coating in incandescent reflector

lamps, silver coatings can also be applied. Silver coatings are generally preferred over aluminum

due to their lower light loss (silver reflects about eight percent more light based on commercially

available lamps). One manufacturer currently holds a patent on the silverized reflector coating

technology that will not expire until December 2019 1

. Therefore DOE considered the silverized

reflector coating to be a proprietary technology. A proprietary technology could give one

manufacturer an unfair advantage over competing manufacturers. However, DOE is also aware

of possible technologies employing the use of silver that may not fall under the proprietary

restrictions and may be used to enhance reflector efficiencies. 2 However, to DOE’s knowledge,

these alternate technologies are still in development.

5D.2.3 A lternative method

DOE i nvestigated the possibility that TSL 5 could be achieved without using a silverized

reflector coating. DOE reviewed design options that met all required screening criteria (see

chapter 4 for details) and discovered the existence of a more efficient IR coating than that

currently in use in the lighting industry.

To prove t he effectiveness of this coating, ADLT obtained commercially available

capsules, applied the advanced IR coating, and sent the capsules to the Lighting Research Center

(LRC) in Rochester, NY for independent testing. The following sections describe the method the

LRC used for testing and the results.

5D.3 M ETHOD

5D.3.1 C apsules

ADLT provided the LRC with IR coated halogen burners for evaluation. ADLT informed

DOE that when used with the two­material coating for which they were originally designed,

these burners operate at 60 W, delivering 24 lm/W. The design life and temperature are 3000 hrs

and 2880 K. They are double­ended, elliptical quartz burners, with lengths of 4.5 cm, excluding

the electrodes, and minor elliptical axes of 1.0 cm.

This s hape and size readily accommodates use in most IRL, as evidenced by products now on the

market. ADLT claims that such products exist in R20, BR30, BR40 and PAR38 formats. In

5D­2addition, outside the IRL configuration, ADLT claims that a commercially­available A­line

general service incandescent lamp product, incorporates a burner of the same shape and

size. These commercially available examples operate at 120 V at various powers. The LRC

measured the lumens and watts of these capsules according to DOE’s test procedure for testing

incandescent reflector lamps (title 10 Code of Federal Regulations (CFR) part 430, subpart B,

appendix R).

5D.3.2 M odifying voltage

As m entioned in section 5D.2.1, IR coatings increase the operating temperature of an

HIR lamp, which in turn decreases the lifetime. According to ADLT, the commercially available

halogen burners with a standard IR coatings, have rated lifetimes of approximately 3,000 hours

when operated at 120V. Because the advanced IR coating reflects more IR radiation than the

standard IR coating, the lamp’s operating temperature increases, resulting in a decrease of lamp

lifetime. ADLT performed tests and determined that the burners with the advanced IR coatings

supplied by ADLT have lifetimes of approximately 1,200 hours. In order to determine the

efficacy of a 3,000 hour lamp with an advanced IR coating, DOE lowered the operating voltage

of the ADLT burners such that the measured correlated color temperature (CCT) (representative

of operating temperature) was the same as that of the commercially available lamp with the

standard IR coating. DOE assumed this modification reasonably approximated a 3,000 hour

lamp.

5D.3.3 R eflector

A burner a nd reflector combined emit less light than the burner alone due to light losses

attributable to the reflector. Because the burners provided by ADLT are not sold commercially

as a reflector lamp assemblies, DOE calculated the potential efficacy of an IRL utilizing an

advanced IR coated burner. To do this, DOE first calculated the lumen reduction due to

reflectors in commercially available lamps. DOE then applied these same percentage lumen

reductions to the burners provided by ADLT.

The L RC bought and analyzed five existing lamps from two different manufacturers to

evaluate the lumen losses due to reflectors. It tested each burner­reflector assembly and burner

(separate from the reflector) three times and averaged the measured lumens across the three tests.

Using these average lumens from the burner and the average lumens from the burner­reflector

assembly, DOE then calculated the percent lumen loss due to each lamp reflector. DOE applied

this percentage to calculate the lumen loss due to a reflector for the burners supplied by ADLT.

5D.4 R ESULTS

5D.4.1 A DLT Burners

5D­3Table 5D.1 shows the average lumens, power, and efficacy of the ADLT burners at

120V, whereas Table 5D.2 below shows the same metrics with the burners operating at reduced

temperature. As seen in the tables below, reducing the operating temperature to obtain a lifetime

of 3,000 hours instead of 1,200 hours results in a decrease in efficacy of about 5.6 lm/W.

Table 5 D.1 Test Results for Burners with Advanced IR Coating

Reflector

& Burner Burner

A verage L ight Output lumens

­ 2 116.9

A verage P ower watts

­ 5 7.0

A verage Ef ficacy lm/W

­ 3 7.1

A verage V oltage V 120V

T able 5 D.2 Test Results for Burners with Advanced IR Coating Operating at a Reduced

Operating Temperature

Reflector

& Burner Burner

A verage L ight Output lumens

­ 1 513.8

A verage P ower watts

­ 4 8.1

A verage Ef ficacy lm/W

­ 3 1.5

A verage V oltage V

­ 107

5 D.4.2 R eflector Losses

5D.4.2.1 C ommercially Available Lamps

The L RC tested each commercially available burner and burner­aluminum reflector

assembly three times for repeatability and calculated an average value. The average lumens,

watts, and efficacies for the five commercially available lamps are shown in Table 5D.3.

Table 5 D.3 Test Results for Commercially Available HIR Lamps

Reflector &

Burner Burner

M anufacturer

A Average L ight Output lumens 9 93.3 1 358.3

A verage P ower watts 6 1.3 6 1.7

A verage Ef ficacy lm/W 1 6.2 2 2.0

M anufacturer

A Average L ight Output lumens 9 78.0 1 151.7

A verage P ower watts 5 6.6 5 6.9

A verage Ef ficacy lm/W 1 7.3 2 0.2

M anufacturer

A Average L ight Output lumens 9 83.7 1 141.0

A verage P ower watts 5 3.6 5 3.7

A verage Ef ficacy lm/W 1 8.4 2 1.2

5D­4Manufacturer Average L ight Output lumens 7 80.3 9 75.9

B Average P ower watts 5 1.7 5 1.8

A verage Ef ficacy lm/W 1 5.1 1 8.9

M anufacturer A verage L ight Output lumens 1 057.0 1 349.0

B Average P ower watts 6 2.1 6 2.3

A verage Ef ficacy lm/W 1 7.0 2 1.7

A s s hown in the table above, Manufacturer A’s best reflector maintains 86.2% of the

light from the capsule alone, whereas the worse reflector maintains 73.1% of the light.

Manufacturer B’s best reflector maintains 79.9% of the light from the capsule alone, whereas the

worse reflector maintains 78.4% of the light. Using these percentages, it is possible to calculate

a best and worst case scenario. The best case scenario would use the reflector that maintains

86.2% of the light, where as the worst case scenario would use the reflector that maintains 73.1%

of the light.

5D.4.2.2 A DLT Burners

Using t he percentages described in the previous section, DOE calculated the most

efficient and least efficient burner­reflector combination that uses the ADLT burners. Table

5D.4 shows the results.

Table 5 D.4 Calculated Efficacies for ADLT Burner­Reflector Assemblies

Reflector &

Burner Burner

B est C ase

Scenario,

86.2% reflector Average L ight Output lumens 1 305 1 513.8

A verage P ower watts 4 8.1 4 8.1

A verage Ef ficacy lm/W 2 7.1 3 1.5

W orst C ase

Scenario,

73.1% reflector Average L ight Output lumens 1 107 1 513.8

A verage P ower watts 4 8.1 4 8.1

A verage Ef ficacy lm/W 2 3.0 3 1.5

A s o utlined in section VI.A.2 of the NOPR, energy conservation standards for IRL are

dependent upon the wattage of the lamp. The relevant equation that defines the minimum

efficacy standard associated with TSL 5 is 6.9P 0.27

, where P is the rated wattage. If 48W were

the rated wattage of the lamp in the table above, the corresponding efficacy level at TSL 5 would

be 19.6 lm/W. With an efficacy of at least 23.0 lm/W, the ADLT burner­reflector assembly

would meet TSL 5. As TSL 5 represents the highest efficacy levels, the ADLT burner­reflector

assembly would also meet all other TSLs.

5D.5 L ONG LIFE

As d iscussed in section 5D.2.1, HIR technology results in lamps operating at higher

temperatures. This, in turn, decreases lamp lifetime because the tungsten filament evaporates

5D­5more quickly. DOE intends to show here that using an advanced IR coating to meet TSL 5 will

not eliminate long­life HIR lamps from the market.

Using t he 9 th edition of the IESNA Lighting Handbook 3

, DOE developed a relationship

between lifetime, lumens, and wattage for two different lamps. Using the known power, lumens,

and lifetime for the 3,000 hour improved HIR lamp, DOE was able to calculate the lumens of the

HIR lamp if it had the same power but a lifetime of 6,000 hours. Table 5D.5 shows the

calculated lumens and efficacy for a 6,000 hour HIR lamp that employs an advanced IR coating.

Table 5 D.5 Calculated Efficacy for a Long Life (6,000 hours) IRL using an ADLT

Advanced IR burner

Reflector &

Burner

Best C ase

Scenario,

86.2% reflector Average L ight Output lumens 1 188

A verage P ower watts 4 8.1

A verage Ef ficacy lm/W 2 4.7

W orst C ase

Scenario,

73.1% reflector Average L ight Output lumens 1 007

A verage P ower watts 4 8.1

A verage Ef ficacy lm/W 2 1.0

A s d escribed in section 5D.4.2.2, the minimum efficacy requirement at each TSL varies

based on the rated wattage of the lamp. If the rated wattage is 48W, the corresponding

minimum efficacy requirement at TSL 5 would be 19.6 lm/W. Similarly, the minimum efficacy

requirement at TSL 4 for the same lamp would be 17.6 lm/W. As shown in Table 5D.5, both the

best case and worst case scenario meet TSL 5. Therefore, DOE believes that TSL 5 does not

eliminate long­life lamps from the market.

5D.6 P RICE

To consider t his advanced IR technology as an alternate technology pathway to achieve

TSL5, DOE also analyzed potential manufacturing cost and price impacts to this technology.

ADLT provided DOE with estimates of the cost of applying the advanced IR coating described

in section 5D.2.1 to an existing capsule. It estimated the cost to the lamp manufacturer of adding

the advanced IR coating to be $0.68 per burner if one million capsules were coated per year 4

. Lamp manufacturers have the option of paying ADLT to apply the advanced IR coating or

acquiring a machine and coating their own lamps. ADLT expects the price to decrease to $0.20

per burner if 500 million or more capsules were coated per year.

To best d etermine the price of a lamp with an advanced IR coating, DOE added the

incremental cost of the advanced IR coating to the price of a lamp at TSL 4 (see TSD chapter 7).

TSL 4 is represented by a HIR lamp with a standard IR coating and a 4,000 hour lifetime.

ADLT estimated the cost of a standard IR coating, described in section 5D.2.1, to be $0.50 per

burner if one million capsules were coated per year, decreasing to $0.15 per burner if 500 million

or more burners were coated per year. Therefore, based on these numbers, the incremental cost

5D­6to manufacturers of the advanced coating would be approximately $0.18 per burner in small

quantities or $0.05 per burner in large quantities.

In c onsideration of the current state of the technology and its production volume, a lamp

currently manufactured with this advanced IR coating technology would be subject to lower

volume cost estimates. In the manufacturer impact analysis (MIA), DOE used a multiplier of 2.3

to calculate the end­user price if given the cost to the lamp manufacturer. Using this multiplier,

the manufacturer cost differential between a standard IR coated lamp and an advanced IR coated

lamp results in an incremental cost of $0.41 to the end user. Adding this incremental cost to the

price of a lamp at TSL 4, DOE calculates the medium price of a PAR38 lamp with an advanced

IR coating at TSL 5 to be $7.91 and calculates the medium price of a PAR30 lamp to be $7.34.

5D.7 C ONCLUSION

As s hown in section 5D.4.2.2, testing indicates that it is possible to achieve TSL 5

without using silverized reflector technology. An advanced IR coating, which, to DOE

knowledge, would be available to all lamp manufacturers can likely be used to meet TSL 5. In

addition, as shown in section 5D.5, TSL 5 does not appear to eliminate long­life lamps from the

market. Using a relationship derived from the IESNA Lighting Handbook, DOE concluded that

a 6,000 lamp with an advanced IR coating can still achieve TSL 5.

In s ection 5D.6, DOE calculated the cost of a lamp with an advanced IR coating by

adding the marked up cost of the coating to the price of a lamp at TSL 4. The analysis found

these prices to be comparable with IRL that meet TSL 5 and utilize the proprietary silverized

reflector technology.

5D­7REFERENCES

1 Zhao, Tianji, et al. “Protected Coating for Energy Efficient Lamp.” U.S. Patent 6,773,141.

August 10, 2004.

2 http://www.depsci.com/Documents/SubHeading/DSIannouncesEcoWhiteFINAL.pdf (Last

A ccessed: December 10, 2008)

3 Rae, Mark S., ed. The I ESNA Lighting Handbook, Reference & Application

, 9th e dition, New

York, NY, IESNA 2000.

4 Boling, Norm. <bolingn@depsci.com> “FW: pricing” 8 December 2008. Personal email. (9

December 2008).

5D­8