4

- i CHAPTER 4. SCREENING ANALYSIS

TABLE OF CONTENTS

4.1 INTRODUCTION

................................ ................................ ................................ ......... 4

- 1 4.2 DISCUSSION OF DESIGN OPTIONS

................................ ................................ ........ 4

- 2 4.3 DESIGN OPTIONS NOT S CREENED OUT OF THE A NALYSIS

........................... 4

- 3 4.3.1 Improved Core Steel

................................ ................................ ...................... 4

- 3 4.3.2 Copper Wiring

................................ ................................ ............................... 4

- 3 4.3.3 Increased Stack Height

................................ ................................ .................. 4

- 3 4.3.4 Increased Conductor Cross

- Section

................................ ............................... 4

- 4 4.3.5 Electronic Ballast

................................ ................................ ........................... 4

- 4 4.3.6 Improved Components

................................ ................................ ................... 4

- 5 4.3.7 Improved Circuit Design

................................ ................................ ................ 4

- 5 4.4 DESIGN OPTIONS SCREE NED OUT OF THE ANALY SIS

................................ .... 4

- 5

LIST OF TABLES

Table 4.2.1 Metal Halide Lamp Fixtures Design Options

................................ ............... 4

- 24

- 1 CHAPTER 4. SCREENING ANALYSIS

4.1 INTRODUCTION

This chapter discusses the U.S. Department of Energy’s (DOE ’s ) screening analysis of the technology options identified for metal halide lamp fixtures

. As discussed in chapter 3 of the preliminary technical support document ( TSD )

, DOE consults with industry, technical experts, and other interested parties to develop a list of technology options for consideration

. The purpose of the screening analysis is to determine which options to consider further and which to screen out.

Section 325(o)(2) of the Energy Policy and Conservation Act ( EPCA ) provides that any new or re vised standard must be designed to achieve the maximum improvement in energy efficiency that is determined to be technologically feasible and economically justified

. (42 U.S.C. 6295(o)(2)) In view of the EPCA requirements a ppendix A to

s ubpart C of t itle 1 0, Code of Federal Regulations (CFR)

, p art 430 (10 CFR p art 430), Procedures, Interpretations, and Policies for Consideration of New or Revised Energy Conservation Standards for Consumer Products (the Process Rule) sets forth procedures to guide DOE in its consideration and promulgation of new or revised energy conservation standards

. These procedures elaborate on the statutory criteria provided in 42 U.S.C. 6295(o) and, in part, eliminate problematic technologies early in the process of prescribing or amen ding an energy conservation standard

. In particular, sections 4(b)(4) and 5(b) of the Process Rule provide guidance to DOE for determining which design options are unsuitable for further consideration:

1. Technological feasibility

. DOE will consider technologies incorporated in commercial products or in working prototypes to be technologically feasible.

2. Practicability to manufacture, install, and service

. If mass production and reliable installation and servicing of a technology in commercial products could be achieved on the scale necessary to serve the relevant market at the time the standard comes into effect, then DOE will consider that technology practicable to manufacture, install, and service

.
3. Adverse i mpacts on product utility or product avail ability

. If DOE determines a technology would have significant adverse impact on the utility of the product to significant subgroups of consumers, or would result in the unavailability of any covered product type with performance characteristics (including reliability), features, sizes, capacities, and volumes that are substantially the same as products generally available in the United States at the time, it will not consider this technology further.

4. Adverse impacts on health or safety

. If DOE determines t hat a technology will have significant adverse impacts on health or safety, it will not consider this technology further.4

- 2 4.2 DISCUSSION OF DESIGN OPTIONS

Several well

- established engineering practices and techniques exist for improving the efficiency of a met al halide lamp ballast. Improving the construction materials ( e.g. , core steel, conductor) and modifying the ballast’s geometry ( i.e. , the stack height and conductor gauge) can make a ballast more energy efficient. Increasing core cross

- section, for instan ce, can reduce core losses but requires a greater length of conductor to encircle the larger core and thus increases resistive losses. In electronic ballasts, substituting for higher grade components (e.g., capacitor) or improving the circuit type can also increase efficiency by reducing conduction and switching losses. It takes a great degree of engineering skill to maximize the efficiency gains in the overall design, and there are multiple pathways to achieve a given efficiency level. Table 4.2

. 1 presents a general summary of the options a manufacturer may use to reduce losses in metal halide lamp ballasts.

Table 4.2

. 1 Metal Halide Lamp Fixtures Design Options

Relevant Ballast Type Technology Option Description

Magnetic Improved Core Steel Use a higher grade of electrical steel, including grain

- oriented silicon or amorphous steel, for lower core losses.

Copper Wiring Use copper wiring in place of aluminum wiring for lowered resistive losses.

Increased Stack Height To a point, adding steel laminations results in lowered core loss.

Increased Conductor Cross

- Section To a point, increasing conductor cross section results in lowered winding loss.

Electronic Ballast Use an electronic ballast in place of a magnetic ballast.

Electronic Improved Components Magnetics Use grain

- oriented or amorphous electrical steel to reduce core losses. Use optimized

- gauge copper or litz wire to reduce winding losses. To a point, adding steel laminations results in lowered core loss. To a point, increasing conductor cross section results in lowered winding loss.

Diodes Use d io des with lower losses.

Capacitors Use capacitors with a lower effective series resistance and output capacitance.

Transistors Use transistors with lower drain

- to

source resistance. Improved Circuit Design Integrated Circuits Substitute discrete components with an integrated circuit.4

- 3 4.3 DESIGN OPTIONS NOT S CREENED OUT OF THE A NALYSIS

This section discusses the technology options that DOE considers viable means of improving the efficiency of metal halide lamp fixtures.

4.3.1 Improved Core Steel

Electrical steel, placed in a time

- variant magneti c field, loses energy in two ways. Eddy currents are small, unproductive currents that dissipate energy resistively, whereas hysteresis is a nonlinearity in the magnetization of a material in response to the magnetic field applied. Electrical steels are ma de in different grades which correspond to different losses. Inexpensive magnetic ballasts typically use non

- oriented steel whose magnetic properties are isotropic. Higher grades of steel can be grain

- oriented, where the microscopic structure of the materi al is optimized for a particular field direction, or amorphous, which has no grain structure at all and the most desirable magnetic properties. Though amorphous steel has not yet been incorporated into commercially available metal halide ballasts, DOE did not screen this technology out because it has been used in similar products. These improved core steel types reduce eddy currents and hysteresis losses , and improves ballast efficiency.

Considering the four screening criteria for this technology option, DO E did not screen out improved steel as a core material. Because these materials are in commercial use today, DOE concluded that they are technologically feasible and practicable to manufacture, install, and service. DOE is not aware of any adverse impacts on consumer utility, reliability, health, or safety associated with higher grades of steel.

4.3.2 Copper Wiring

Most inexpensive magnetic ballasts use aluminum conductor, which is more resistive than copper conductor of the same gauge. Because conductor losses v ary in proportion to the resistance of the conductor, lowered resistance yields lower losses and higher ballast efficiency

. Considering the four screening criteria for this technology option, DOE did not screen out copper wiring. Because this material is i n commercial use today, DOE concluded that it is technologically feasible and practicable to manufacture, install, and service. DOE is not aware of any adverse impacts on consumer utility, reliability, health, or safety associated with copper wiring.

4.3.3 Incre ased Stack Height

Losses in electrical steel vary with magnetic flux density, with higher flux density yielding higher losses. For a given magnetic field, increasing core cross

- section will lower flux density and, therefore, lower losses. Because steel lam inations are said to be “stacked” to form a core, increasing core cross

- section is ordinarily done by adding steel laminations, or increasing the stack height. However, a dding steel also adds core losses in4

- 4 the form of eddy currents and hysteresis, and als o requires a greater length of conductor

, eventually offsetting decreased core losses from increased core cross

- section.

Considering the four screening criteria for this technology option, DOE did not screen out increased stack height. Because this practic e is in commercial use today, DOE concluded that it is technologically feasible and practical to manufacturer, install, and service. Increasing stack height could affect the overall size and form factor of the ballast, but DOE believes there is sufficient flexibility in fixtures and the space in which they are installed to accommodate these changes. DOE is not aware of any adverse impacts on consumer utility, reliability, health, or safety associated with increased stack height

.
4.3.4 Increased Conductor Cross

- Se ction

The efficiency of a magnetic ballast could be increased with the use of increased conductor cross

- sections in the windings of the magnetic choke and step

- up transformer. This can be accomplished by both using larger wire gauges (i.e., lower numeric v alues), multiple strands of wire operating in parallel. Using greater cross

- sectional area in the magnetic component windings decreases the winding resistance and associated losses. Increased c ross

- sectional area in the windings could necessitate a longer core or additional layers of wire if the core length cannot be changed to maintain the same electromagnetic properties. This design option typically corresponds to an increase in manufacturing cost.

Considering the four screening criteria for this technolo gy option, DOE did not screen out increased conductor cross

- section. Because increased conductor cross

- section is available in commercially available products today, DOE concluded that this design is technologically feasible and practicable to manufacture, install, and service. Increasing conductor cross

- section could affect the overall size and form factor of the ballast, but DOE believes there is sufficient flexibility in fixtures and the space in which they are installed to accommodate these changes. DOE is not aware of any adverse impacts on consumer utility, reliability, health, or safety associated with the u se of increased conductor cross

- section.

4.3.5 Electronic Ballast

The efficiency of a metal halide ballast can be increased through the use of an electronic ballast rather than a magnetic ballast, particularly at medium to low wattages. Electronic ballasts use m odern, solid

- state components and circuits to perform the same function as magnetic ballasts with lower electrical losses. Electronic ballasts are often more expensive than magnetic ballasts.

Considering the four screening criteria for this technology opti on, DOE did not screen out electronic ballasts. Because electronic ballasts are in commercial use today, DOE concluded that these ballasts are technologically feasible and practicable to manufacture, install, and service. DOE is not aware of any adverse im pacts on consumer utility, reliability, health, or safety associated with the use of electronic ballasts.4

- 5 4.3.6 Improved Components

The efficiency of electronic metal halide ballasts can be increased through the use of improved components. Improved components ca n have reduced electrical losses, increasing overall ballast efficiency, though generally at higher cost than standard components. DOE has not screened out improved components not currently used in metal halide ballasts, as these components are used in rel ated power electronics products.

Considering the four screening criteria for this technology option, DOE did not screen out improved components. Because high

- grade components are in commercial use today, DOE concluded that these components are technologica lly feasible and practicable to manufacture, install, and service. DOE is not aware of any adverse impacts on consumer utility, reliability, health, or safety associated with the use of improved components.

4.3.7 Improved Circuit Design

The efficiency of electro nic metal halide ballasts can be increased through the use of improved circuit designs through the use of integrated circuits. The use of integrated circuits provides for more advanced control of the operation of the ballast. The use of integrated circuits also allows for use of more advanced and higher grade components, such as improved transistors. More advanced control of the ballast makes efficiency gains possible in the overall ballast, though generally at higher cost than standard designs

.
Considerin g the four screening criteria for this technology option, DOE did not screen out improved circuit designs. Because improved circuit designs (such as the use of integrated circuits) are in commercial use today, DOE concluded that these designs are technolog ically feasible and practicable to manufacture, install, and service. DOE is not aware of any adverse impacts on consumer utility, reliability, health, or safety associated with the use of improved circuit designs.

4.4 DESIGN OPTIONS SCREE NED OUT OF THE ANALYSIS

DOE did not screen out any technology options for metal halide lamp fixtures.