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CHAPTER 4. SCREENING ANALYSIS

TABLE OF CONTENTS

4.1 INTRODUCTION .............................................................................................................. 4-1

4.2 SCREENED-OUT TECHNOLGIES .................................................................................. 4-2

4.2.1 Compressor Part Load Operation............................................................................ 4-2

4.2.2 Increased Surface Area for Condensers in Water-Cooled Batch Ice Makers ......... 4-2

4.2.3 Enhanced Fin Surfaces ............................................................................................ 4-3

4.2.4 Increased Condenser Water Flow ........................................................................... 4-3

4.2.5 Brazed Plate Condenser for Water-Cooled Condensers ......................................... 4-4

4.2.6 Increased Evaporator Surface Area (Batch Ice Makers) ......................................... 4-4

4.2.7 Technology Options to Reduce Evaporator Thermal Cycling ................................ 4-4

4.2.8 Technology Options that Reduce Harvest Meltage or Reduce Harvest Time ........ 4-4

4.2.9 Improved or Thicker Insulation .............................................................................. 4-5

4.2.10 Larger Diameter Suction Line (Remote Compressor Equipment) ......................... 4-5

4.2.11 Reduced Potable Water Flow.................................................................................. 4-5

4.2.12 Drain Water Thermal Exchange ............................................................................. 4-5

4.2.13 Technology Options Requiring Ice-Making Head or Self-Contained Unit Size 

Increase ............................................................................................................................... 4-6

4.3 REMAINING TECHNOLOGIES ...................................................................................... 4-8

LIST OF TABLES

Table 4.2.1 Screening Justification .............................................................................................. 4-7

LIST OF FIGURES

Figure 4.2.1 Ice Maker Showing External Installation of Drain Water Heat Exchanger ............ 4-6
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CHAPTER 4. SCREENING ANALYSIS

4.1 INTRODUCTION

This chapter details the screening analysis that the U.S. Department of Energy (DOE) 

conducted in support of the ongoing energy conservation standards rulemaking for automatic 

commercial ice-making (ACIM) equipment. 

In the market and technology assessment (chapter 3 of the preliminary technical support 

document (preliminary TSD)), DOE presents an initial list of technologies that can improve the 

energy efficiency of automatic commercial ice makers. The purpose of the screening analysis is 

to evaluate the technologies that improve equipment efficiency to determine which technologies 

to consider further and which to screen out. DOE consulted with a range of parties, including 

ACIM industry representatives, technical experts, and others, to develop a list of technologies for 

consideration. DOE evaluated the technologies pursuant to the criteria set out in the Energy 

Policy and Conservation Act (EPCA), as amended. (42 U.S.C. 6311–6317) 

EPCA establishes criteria for prescribing new or amended standards designed to achieve 

the maximum improvement in energy efficiency. Further, EPCA directs the Secretary of Energy 

to determine whether a standard is technologically feasible and economically justified. (42 

U.S.C. 6295(o)(2)(A)–(B) and 6313(d)(4)) 

Appendix A to subpart C of 10 CFR part 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 equipment 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 amending an energy conservation standard. In particular, 

sections 4(b)(4) and 5(b) of the Process Rule guide DOE in determining whether to eliminate 

from consideration any technology that presents unacceptable problems with respect to the 

following criteria. To fulfill statutory criteria for prescribing energy standards for automatic 

commercial ice makers as established in 42 U.S.C. 6295(o) and 6313(d)(4), DOE applied the 

provisions in the Process Rule in its screening analysis for this rulemaking. 

Technological feasibility. Technologies incorporated in commercial equipment or in 

working prototypes will be considered technologically feasible. 

Practicability to manufacture, install, and service. If mass production of a technology 

in commercial equipment and reliable installation and servicing of the technology could be 

achieved on the scale necessary to serve the relevant market at the time of the effective date of 

the standard, then that technology will be considered practicable to manufacture, install, and 

service.

Impacts on equipment utility or equipment availability. If a technology is determined 

to have a significant adverse impact on the utility of the equipment to significant subgroups of 

customers, or result in the unavailability of any covered equipment type with performance 

characteristics (including reliability), features, sizes, capacities, and volumes that are 
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substantially the same as equipment generally available in the United States at the time, it will 

not be considered further. 

Adverse impacts on health or safety. If it is determined that a technology will have 

significant adverse impacts on health or safety, it will not be considered further. 

In sum, if DOE determines that a technology, or a combination of technologies, has 

unacceptable impacts on the policies stated in section 5(b) of the Process Rule, it will be 

eliminated from consideration. If a technology fails to meet one or more of the four criteria, it 

will be screened out. Section 4.2 documents the reasons for eliminating the technologies that 

were screened out. 

4.2 SCREENED-OUT TECHNOLGIES

This section describes the technologies that DOE eliminated for failure to meet one of the 

following four criteria: (1) technological feasibility; (2) practicability to manufacture, install, and 

service; (3) impacts on equipment utility or equipment availability; and (4) adverse impacts on 

health or safety. The discussion also points out which technologies have not been analyzed in the 

engineering and downstream analyses for other reasons, including that they don’t save energy, 

their energy savings are not captured in the test procedure, or they are proprietary. 

However, DOE intends to consider reversing the screening decisions on some of the 

technologies in the notice of proposed rulemaking (NOPR) phase, depending on comments and 

information received on the preliminary analysis. This applies to the following technologies: 

• potable water use reduction

• condenser water use increase

• technology options to reduce evaporator thermal cycling

• drain water thermal exchange

• technology options requiring size increase 

4.2.1 Compressor Part Load Operation

While there may be benefits associated with operation of an ice maker compressor at part 

load when ice demand is moderate or low, DOE is not aware of any commercialized product or 

prototype that has been constructed and tested to illustrate the benefits and/or reliability of this 

technology option. Hence, this technology option must be screened out based on the technical 

feasibility criterion. 

4.2.2 Increased Surface Area for Condensers in Water-Cooled Batch Ice Makers

Increased condenser surface area has been screened out in the preliminary analysis for 

water-cooled batch ice makers. Condenser water flow in water-cooled condensers is controlled 

using water flow control valves that adjust the flow to maintain a constant condensing pressure. 

DOE test data show that the condensing temperature of a typical water-cooled batch ice maker 

stays relatively constant, demonstrating that the condensers are sized well for their peak loads, 

which occur near the start of the freeze cycle. Because of the water valve control, larger 
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condensers would not significantly reduce condensing temperature. The valve setting would also 

have to be adjusted to reduce the condensing temperature and thereby achieve significant energy 

savings. 

Based on discussions with manufacturers during the preliminary analysis phase, a 

significant reduction in condensing temperature to reduce freeze cycle energy use would 

compromise harvest performance, leading to potential reliability concerns and/or increasing 

harvest cycle energy use such that overall energy use would not decrease. Specifically, a 

reduction in condensing temperature would reduce the amount of heat available in the 

compressor to achieve harvest, because the compressor power input during the freeze cycle 

would be reduced. During the harvest cycle, the compressor heat is rapidly transferred to the 

evaporator. As the amount of heat available is reduced (i.e., as a result of lower condensing 

temperature during the freeze cycle), at some point the harvest cycle impacts would likely negate 

any further energy use benefits. The appropriate typical freeze cycle condensing temperatures 

used by manufacturers have presumably been selected based on testing. The condensing pressure 

or temperature setpoints of condenser water control valves are very consistent across the industry 

(based on manufacturer interviews and ice maker testing). Hence, DOE believes that the industry 

has optimized water-cooled condenser design and operating parameters and that the potential for 

improvement through condenser size increase is limited. This design option has been screened 

out based on reliability concerns associated with avoidance of freeze-ups as well as insignificant 

potential for energy savings. 

Note that stakeholders have commented that condenser water flow rate could be reduced 

through use of larger water-cooled condensers. (Scotsman, No. 22 at p. 5a

) In the NOPR phase, 

DOE may consider use of this design option in combination with condenser water flow reduction 

to allow consideration of other energy saving design options within a given life-cycle cost target. 

See chapter 2 of the preliminary TSD for further discussion of integrating reduction of condenser 

water use into the analysis. 

4.2.3 Enhanced Fin Surfaces

DOE is not aware of any enhanced fin surfaces available for air-cooled condensers that 

would significantly improve heat transfer and efficiency in automatic commercial ice makers that 

are not already used extensively in the industry for air-cooled models. Hence, DOE is screening 

out this option because it is already in use and does not represent an option for improved 

efficiency.

4.2.4 Increased Condenser Water Flow

DOE did not consider condenser water flow increase as a design option in the preliminary 

analysis because ice makers covered under the current DOE regulations have standards 

specifying maximum allowable condenser water use. For other ice makers, in the preliminary 

 

a A notation in this form provides a reference for information that is in the docket of DOE’s rulemaking to develop 

energy conservation standards for automatic commercial ice makers (Docket No. EERE-2010-BT-STD-0037), 

which is maintained at www.regulations.gov. This notation indicates that the statement preceding the reference is 

document number 22 in the docket for the ACIM energy conservation standards rulemaking, and appears at page 5 

of that document.
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analysis DOE expected that condenser water use standard levels would be set that would 

preclude consideration of technologies that increase condenser water flow. Also, as described in 

section 4.2.2, condensing temperature reductions can degrade harvest performance, which could 

affect reliability. However, as part of the NOPR phase analyses DOE intends to consider 

condenser water flow increase, depending on comments and input received on the preliminary 

analysis. Condenser water flow increase is discussed in chapter 2 of the preliminary TSD. 

4.2.5 Brazed Plate Condenser for Water-Cooled Condensers 

DOE has concluded that use of brazed plate condensers does not represent a viable design 

option for batch ice makers because (1) most ice makers using water-cooled condensers have 

space for condenser surface area growth rather than requiring use of more expensive condenser 

technology such as brazed plate; and (2) for batch ice makers, as described in section 4.2.2

reduction of condensing temperature reduces the effectiveness of harvest and is not expected to 

significantly reduce energy use. 

4.2.6 Increased Evaporator Surface Area (Batch Ice Makers)

DOE has determined that an increase in the size of batch ice maker evaporators would 

generally require an increase in the size of the ice-making head of the ice maker, or, for selfcontained ice makers, would either reduce ice storage capacity or require an increase in the size

of the ice maker. These impacts represent reductions in utility; hence, this design option was not 

considered in the preliminary analysis. See also the discussion of size increase in section 4.2.13. 

4.2.7 Technology Options to Reduce Evaporator Thermal Cycling 

Although there are numerous patents identifying evaporator design concepts that would 

reduce thermal mass and thus reduce evaporator thermal cycling, DOE was able to identify only 

one such technology, used in ice makers sold by Hoshizaki America, Inc., that has demonstrated 

technical feasibility (i.e., is commercially available or for which prototype test data are publicly 

available). The Hoshizaki evaporator design has significantly less thermal mass than the 

evaporator designs of most other ice maker manufacturers. While some patents associated with 

this evaporator design have expired or are at their end of their applicable life, others are not. 

DOE has not determined conclusively whether the Hoshizaki design is proprietary. However, 

DOE did not include reduced evaporator thermal cycling as a design option in its preliminary 

analysis. DOE requests information on the status of this technology in the preliminary TSD 

executive summary. Depending on the information obtained, DOE may consider this technology 

option in the NOPR engineering analysis. 

4.2.8 Technology Options that Reduce Harvest Meltage or Reduce Harvest Time

As discussed in chapter 3, manufacturers have implemented design changes to reduce 

harvest meltage and reduce harvest time in batch ice makers. DOE has been unable to identify 

additional design changes that are not already in use in the industry to further improve harvest 

cycle efficiency. Hence, for most batch ice makers, this technology option is screened out 

because it does not save additional energy. However, some ice makers do not incorporate all of 

the available techniques used by manufacturers to improve harvest, so DOE has considered this 
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option selectively in the engineering analysis (chapter 5 of the preliminary TSD), based on 

specific equipment characteristics.

4.2.9 Improved or Thicker Insulation

Insulation used in ice makers may reduce thermal loss, but, as indicated by stakeholders 

in comments (see chapter 2 of the preliminary TSD), it is primarily used to prevent condensation 

of water on cold surfaces. A small amount of additional thermal loss could be prevented through 

the use of improved or thicker insulation. However, the impact of this efficiency improvement is 

small enough to be nearly immeasurable. Hence, this technology option has been screened out. 

4.2.10 Larger Diameter Suction Line (Remote Compressor Equipment)

Increasing the suction line diameter could be considered to reduce suction line pressure 

drop for remote condenser equipment with remote compressors. However, the reduced suction 

vapor velocity associated with the approach can degrade oil return effectiveness. Remote ice 

maker line sets can be installed in the field so that suction line refrigerant runs up, down, or 

horizontally to the compressor; hence, they are conservatively sized to provide adequate oil 

return for a wide range of installation conditions. DOE has not considered increase in suction 

line size in the preliminary analysis due to reliability concerns associated with potential oil holdup and compressor failure associated with larger-diameter line sets.

4.2.11 Reduced Potable Water Flow

Stakeholders have commented regarding the potential pitfalls of reducing potable water 

flow (see chapter 2 of the preliminary TSD). DOE did not consider this design option in the 

preliminary analysis due to concerns about reliability and increased maintenance costs associated 

with the potential for scaling (i.e., dissolved solids in the water coming out of solution on 

icemaker surfaces). DOE may consider this design option in the NOPR phase analyses, and 

requests quantitative information regarding acceptable lower limits on potable water use for 

batch ice makers.

4.2.12 Drain Water Thermal Exchange 

DOE is aware that suppliers have offered heat exchangers for use in ice makers for drain 

water thermal exchange. However, because DOE initially was not able to identify any suppliers 

currently offering such components, DOE could not properly assess the efficiency/cost 

relationships. For this reason, this technology was not considered in the preliminary analysis. 

Subsequently, DOE was able to identify one available product that appears to be sold 

only for aftermarket installation, Chill Ice.

b This product is installed external to the ice maker, 

and both drain water and supply water are piped through the device, as illustrated in Figure 4.2.1. 

DOE has considered whether such a component could be part of an ice maker as defined in 

EPCA. The EPCA definition for automatic commercial ice makers states that the ice maker 

consists of a condensing unit and ice-making section operating as an integral unit, with means for 

making and harvesting ice. The definition allows that the ice maker may include means for 

 

b www.ajantunes.com/Vizion/CategoryFood.aspx?CategoryId=8#anchor71.
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storing ice, dispensing ice, or storing and dispensing ice. None of the subcomponents of the ice 

maker listed in the definition could be interpreted as referring to heat exchangers for drain water 

thermal exchange. DOE notes that an ice maker can still make ice without a drain water heat 

exchanger; hence, the heat exchanger cannot be considered an essential part of the equipment. 

For these reasons, DOE has concluded that such a component would not be part of the ice maker 

and therefore could not, in this configuration, be considered as a design option. 

If the drain water heat exchanger were integrated into the ice-making head package, a 

possible alternative design configuration, the conclusion would be different. However, in such an 

embodiment, space would have to be made for the heat exchanger, and the ice-making head 

package size would have to increase. DOE did not consider such size increases in the preliminary 

analysis due to concerns about the associated consumer utility impact (see further discussion of 

size increase in section 4.2.13). In addition, DOE was not able to identify any information 

showing the performance characteristics of such a drain water heat exchanger. Depending on 

stakeholder input, consideration of the impacts of ice maker head size increase, and availability 

of relevant technical information regarding performance of an integrated drain water heat 

exchanger, DOE may consider this technology in the engineering analysis as part of the NOPR 

phase.

Figure 4.2.1 Ice Maker Showing External Installation of Drain Water Heat Exchanger 

4.2.13 Technology Options Requiring Ice-Making Head or Self-Contained Unit Size 

Increase

For the preliminary analysis, DOE has screened out design options that require an 

increase in equipment size. These design options include an increase in surface area for air-
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cooled condensers and batch ice maker evaporators and a potential configuration for drain water 

thermal exchange. DOE has taken this approach in the preliminary analysis due to the equipment 

utility reduction associated with an increase in equipment size. Limited space is available in 

kitchens for larger ice-making heads or self-contained unit cabinets. In addition, a large 

percentage of the market involves replacement of old products at the end of their useful life—

allowing size increases would force use of lower-capacity machines in replacement applications, 

a clear reduction in equipment utility. DOE’s analysis makes an exception for remote 

condensers, for which DOE believes installers have more flexibility to find space. 

Not allowing an increase in equipment size affects some design options more than others. 

DOE determined in the preliminary analysis that a limited increase in air-cooled condenser size 

is possible within the confines of some ice maker products, but this was not true for all air-cooled 

products analyzed. However, DOE has not considered an increase in the size of batch product 

evaporators because of the impacts associated with increased size.

DOE may reconsider screening out this design option, and specifically requests comment 

on this issue in the preliminary TSD executive summary.

Table 4.2.1 summarizes the technologies that were screened out for the preliminary 

analysis or were not considered in the engineering analysis for other reasons. 

Table 4.2.1 Screening Justification

Design Option

EPCA Criteria for Screening Not Considered in the Analysis 

for Other Reasons

Technological 

Feasibility

Practicability to 

Manufacture, Install, 

and Service

Adverse Impacts on 

Product Utility

Adverse Impacts on 

Health and Safety

No 

Energy 

Savings or 

Savings not 

Measurable

Test 

Procedure 

Efficiency 

Metric 

Does 

Not 

Capture 

Savings

Proprietary 

Technology

Compressor Part Load Operation √ √

Increased Surface Area for WaterCooled Condensers in Batch Ice Makers√ √

Enhanced Fin Surfaces √

Increased Condenser Water Flow √

Brazed Plate Condenser √

Increased Evaporator Surface Area 

(Batch Ice Makers)

√

Technology Options to Reduce 

Evaporator Thermal Cycling

√

Technology Options Which Reduce 

Harvest Meltage or Reduce Harvest 

Time

√

Improved or Thicker Insulation √

Larger Diameter Suction Line √

Reduced Potable Water Flow √

Drain Water Thermal Exchange √
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4.3 REMAINING TECHNOLOGIES

After eliminating those technologies that are proprietary, have no significant effect, or do 

not reduce energy use as measured by the test procedure, and screening out those technologies 

that do not meet the requirements of sections 4(a)(4) and 5(b) of the Process Rule, DOE 

considered the following technologies in the preliminary analysis: 

• improved compressor efficiency 

• increased condenser surface area (except for water-cooled batch ice makers)

• increased condenser air flow

• higher efficiency condenser fans and fan motors 

• improved auger motor efficiency 

• improved pump motor efficiency 

• increased evaporator surface area (continuous ice makers only) 

• design options which reduce harvest meltage or reduce harvest time (limited 

consideration depending on existing equipment characteristics)