5

- i CHAPTER 5

. ENGINEERING ANALYSIS

TABLE OF CO NTENTS

5.1 INTRODUCTION

................................ ................................ ................................ ........... 5

- 1 5.2 METHODOLOGY OVERVIEW

................................ ................................ .................... 5

- 2 5.2.1 Cooled Cabinets and Non

- Compressor Refrigerators

................................ ...................... 5

- 2 5.2.2 Ice Makers

................................ ................................ ................................ ........................ 5

- 3 5.3 DATA COLLECTION

................................ ................................ ................................ .... 5

- 4 5.3.1 Review of Previous Technical Support Documents and Models, Product Literature, and Product Databases

................................ ................................ ................... 5

- 4 5.3.2 Energy Tests

................................ ................................ ................................ ..................... 5

- 4 5.3.3 Manufacturer Interviews

................................ ................................ ................................ .. 5

- 5 5.3.4 Component Vendors

................................ ................................ ................................ ........ 5

- 5 5.3.5 Reverse Engineering

................................ ................................ ................................ ........ 5

- 6 5.4 MANUFACTURING COST M ODELING

................................ ................................ ..... 5

- 9 5.4.1 Generation of Bill of Materials

................................ ................................ ........................ 5

- 9 5.4.2 Cost Structure of the Spreadsheet Models

................................ ................................ ....... 5

- 9 5.4.3 Cost Model and Definitions

................................ ................................ ........................... 5

- 10 5.4.4 Cost Model Assumptions

................................ ................................ ............................... 5

- 11 5.4.5 Manufacturing Production Cost

................................ ................................ ..................... 5

- 13 5.4.6 Incremental Cost Estimates

................................ ................................ ............................ 5

- 14 5.4.7 G&A and Profit

................................ ................................ ................................ .............. 5

- 15 5.5 ENERGY MODELING

................................ ................................ ................................ . 5

- 15 5.5.1 ERA Model Overview

................................ ................................ ................................ ... 5

- 16 5. 5.2 Development and Calibration of ERA Models

................................ .............................. 5

- 17 5.6 COOLED CABINET AND N ON

- COMPRESSOR REFRIGERA TOR DESIGN OPTIONS

................................ ................................ ................................ ....................... 5

- 19 5.6.1 Brushless DC Fan Motors

................................ ................................ .............................. 5

- 19 5.6.2 Insulation Thickness

................................ ................................ ................................ ...... 5

- 20 5.6.3 Vacuum

- Insulated Panels

................................ ................................ ............................... 5

- 20 5.6.4 Improved Compressor Efficiency

................................ ................................ .................. 5

- 21 5.6.5 Variable

- Speed Compressor

................................ ................................ .......................... 5

- 21 5.6.6 Forced Convection Evaporator

................................ ................................ ...................... 5

- 22 5.6.7 Improved Glass Door Resistivity

................................ ................................ ................... 5

- 22 5.6.8 Conversion to Vapor Compression

................................ ................................ ................ 5

- 23 5.6.9 Heat Pipe

................................ ................................ ................................ ........................ 5

- 24 5.7 COOLED CABINET ANALY SIS AND RESULTS

................................ .................... 5

- 24 5.7.1 CEC

- Equivalent Efficiency Level

................................ ................................ ................. 5

- 24 5.7.2 Energy Test Results

................................ ................................ ................................ ....... 5

- 25 5.7.3 Efficiency Levels

................................ ................................ ................................ ........... 5

- 27 5.7.4 Cooled Cabinet Results

................................ ................................ ................................ .. 5

- 295

- ii 5.8 NON

- COMPRESSOR REFRIGERA TOR ANALYSIS AND RES ULTS

................... 5

- 33 5.8.1 Energy Test Results

................................ ................................ ................................ ....... 5

- 33 5.8.2 Efficiency Levels

................................ ................................ ................................ ........... 5

- 34 5.8.3 Non

- Compressor Refrigerator Results

................................ ................................ ........... 5

- 35 5.9 ICE MAKER ANALYSIS A ND RESULTS

................................ ................................ . 5

- 36 5.9.1 Energy Test Results

................................ ................................ ................................ ....... 5

- 36 5.9.2 Efficiency Levels

................................ ................................ ................................ ........... 5

- 37 5.9.3 Ice Maker Results

................................ ................................ ................................ .......... 5

- 39 5.10 HYBRID REFRIGERATION PRODUCTS ANALYSIS AN D RESULTS

................. 5

- 40 5.10.1 Comparison of Hybrid and Conventional Refrigeration Products

................................ . 5

- 40 5.10.2 Analysis Approach

................................ ................................ ................................ ......... 5

- 42 5.10.3 Results

................................ ................................ ................................ ............................ 5

- 45
REFERENCES

................................ ................................ ................................ .......................... 5

- 47

LIST OF TABLES

Table 5.1 Cost Model In

- House Manufacturing Operation Assumptions

................................ . 5

- 12 Table 5.2 Factory Parameter Assumptions

................................ ................................ ................ 5

- 12 Table 5.3 Comparison of ERA Results and Test Results for Vapor

- Compression Cooled Cabinets

................................ ................................ ................................ .............. 5

- 18 Table 5.4 Design Opt ions

................................ ................................ ................................ .......... 5

- 19 Table 5.5 Glass Door Design Options

................................ ................................ ....................... 5

- 23 Table 5.6 Cooled Cabinet CEC

- Equivalent Efficiency Level Energy Consumption

................ 5

- 25 Table 5.7 Vapor

- Compression Cooled Cabinet Energy Ratings vs. Test Results

..................... 5

- 26 Table 5.8 Non

- Compressor Cooled Cabinet Tested Energy Use

................................ .............. 5

- 26 Table 5.9 Cooled C abinet Efficiency Levels

................................ ................................ ............. 5

- 28 Table 5.10 Cooled Cabinet Efficiency Levels and Design Options

................................ .......... 5

- 29 Table 5.11 6 ft 3 Cooled Cabinet Efficiency Levels

................................ ................................ .... 5

- 30 Table 5.12 Incremental Manufacturer Selling Price (MSP) for 6 ft 3 Cooled Cabinets

.............. 5

- 30 Table 5.13 2 ft 3 C ooled Cabinets Efficiency Levels

................................ ................................ .. 5

- 32 Table 5.14 Incremental Manufacturer Selling Price (MSP) for 2 ft 3 Cooled Cabinets

.............. 5

- 32 Table 5.15 Non

- Compressor Refrigerator Energy Test Results

................................ ................ 5

- 33 Table 5.16 Baseline and Max

- Available Non

- Compressor Refrigerator Efficiency Levels

..... 5

- 34 Table 5.17 Non

- Compressor Refrigerator Efficiency Levels and Design Options

................... 5

- 35 Table 5.18 Incremental MSP for Non

- Compressor Refrigerators

................................ ............. 5

- 36 Table 5.19 Ice Maker Test Results

................................ ................................ ............................ 5

- 36 Table 5.20 Portable Ice Maker Efficiency Levels

................................ ................................ ..... 5

- 37 Table 5.21 Cooled

- Storage Ice Maker Efficiency Levels

................................ .......................... 5

- 38 Table 5.22 Uncooled

- Storage Ice Maker Efficiency Levels

................................ ...................... 5

- 38 Table 5.23 Incremental Manufacturer Selling Price Results for Portable Ice Makers

.............. 5

- 39 Table 5.24 Incremental Manufacturer Selling Price Results for Cooled

- Storage Ice Makers

................................ ................................ ................................ ................ 5

- 395

- iii Table 5.25 Incremental Manufacturer Selling Price Results for Uncooled

- Storage Ice Makers

................................ ................................ ................................ ................ 5

- 40 Table 5.26 Hybrid Product Configuration

................................ ................................ ................. 5

- 43 Table 5.27 Design Options Analyzed for Hybrid Products

................................ ....................... 5

- 43 Table 5.28 Hybrid Refrigeration Product Design Changes

................................ ....................... 5

- 46

LIST OF FIGURE S Figure 5.2.1 Flow Diagram of Engineering Analysis Methodology

................................ ........... 5

- 3 Figure 5.3.1 Vapor

- Compression Cooled Cabinets Selected for Teardown

................................ 5

- 7 Figure 5.4.1 Manufacturing Cost Assessment Stages

................................ ................................ .. 5

- 9 Figure 5.4.2 Full Production Costs

................................ ................................ ............................ 5

- 145-1 CHAPTER 5. ENGINEERING ANALYSIS

5.1 INTRODUCTION
The engineering analysis establishes the relationship between manufacturer production cost (MPC) and energy consumption for the products covered in this rulemaking. The “cost

efficiency” relationship serves as the basis for cost

- benefit calculations for in dividual customers and the Nation

. F rom these calculations, DOE determines the most economically justified and technologically feasible standard level.

The inputs to the engineering analysis include baseline unit specifications from the

mar ket and technol ogy assessment (C hapter 3 of th is preliminary technical support document (TSD)), the design option s from the screening analysis (C hapter 4 of the preliminary TSD ), as well as cost and energy use data collected from manufacturers, component vendors, reverse engineering, and energy testing. The output of the engineering analysis is the cost

- efficiency relationship for each product class, which DOE use s in the life

- cycle cos t and payback period analyses (C hapter 8 of the preliminary TSD) as well as the nationa l impact analysis (Chapter 10 of the preliminary TSD)

. DOE completed separate engineering analys e s for cooled cabinets, non

compressor refrigerators, and ice makers . For hybrid refrigeration products , DOE conducted analysis to support an approach in which the standards for these products would be based on the existing standards for refrigerators, refrigerator

- freezers, and freezers

. DOE typically structures its engineering analysis around one of three methodologies. These are: (1) the design

- option approach , which calculates the incremental costs and energy savings of adding specific design options to a baseline model; (2) the efficiency

- level approach, which calculates the costs of products which are known to have specific energy efficiency levels, without specific focus on the particular design options used to achieve those levels ; and/or (3) the reverse

- engineering or cost

- assessment approach, which involves a “bottom

- up” manufacturing cost assessment based on a detailed bill of materials derived from reve rse engineering teardowns of the product being analyzed. Deciding which methodology to use for the engineering analysis depends on the product, the design options under study, and any historical data that DOE can utilize.5-2 In its engineering analyses for co oled cabinets and non

- compressor refrigerators

, DOE adopted a combined efficiency

- level/design

- option/reverse

- engineering approach to developing
cost

- efficiency curves. For ice makers, DOE adopted an efficiency

- level approach. However, for hybrid refrigera tion products , DOE recognized that these products are substantially similar in design, construction, and operation to the refrigerators, refrigerator

- freezers, and freezers for which DOE has recently conducted a full set of rulemaking analyses, 1 except for the warmer compartments that are also part of hybrid products. Rather than conducting a full set of analyses for hybrid products, DOE conducted analysis to investigate whether the 2014 standards for equivalent refrigerator , refrigerator

- freezer, and freezer product classes could be appropriate for hybrid refrigeration products. DOE’s analysis for hybrid products is described in section 5.10

.

5.2 METHODOLOGY OV ERVIEW
This section describes the analytical methodology DOE used in the engineering analysis for cooled cabinets , non

- compressor refrigerators, and ice makers

. As mentioned above, DOE’s methodology for its analysis for hybrid refrigeration products is des cribed in section 5.10

. DOE conducts engineering analyses on the basis of its test procedures. For the products that are the subject of this rulemaking, DOE does no t have established test procedures, but has issued a Notice of Proposed Rulemaking (NOPR) for test procedures for miscellaneous refrigeration products (“ 2014 MREF TP NOPR”). The engineering analyses for these products are based on the test procedures propo sed in the 2014 MREF TP NOPR.

5.2.1 Cooled Cabinets and Non

- Compressor Refrigerators
DOE adopted a combined efficiency

- level/design

- option/reverse

- engineering approach to developing cost

- efficiency curves for cooled cabinets . DOE established efficiency levels defin ing annual energy use as a percent of the California Energy Commission ( CEC )

- equivalent
energy use

. This is the maximum allowable energy use of the CEC energy standards for wine chillers , adjusted to account for the fact that DOE’s proposed test proce dure (see the 2014 MREF TP NOPR) includes a usage adjustment factor that differs from the factor used in the CEC test procedure. DOE’s analysis is based on the efficiency improvements associated with groups of design options. Also, DOE developed manufactur ing cost models based heavily on reverse engineering of products to support calculation of the incremental costs associated with improvement of efficiency. Figure 5.2

. 1 presents the steps in the cooled cabinet analysis and illustrates how they contributed to developing the cost

- efficiency curves. The process began with data collection and ended with the incremental cost curve results.

To develop the analytically deriv ed cost

- efficiency curves, DOE collected information from various sources on the manufacturing cost and energy use reduction characteristics of each of the design options. DOE reviewed product literature, conducted testing and reverse engineering of curren t products, and interviewed component vendors. DOE also conducted5-3 interviews with cooled cabinet manufacturers. The engineering questionnaire associated with this discussion is reproduced in appendix 5A

.

Figure 5.2

. 1 Flow Diagram of Engineering Analysis Methodology

Cost information from the vendor interviews and engineering questionnaires provided input to the manufacturing cost model. DOE determined incremental costs associated with
sp ecific design options both from vendor information and using the cost model. DOE modeled energy use reduction using the Efficient Refrigerator Analysis (ERA) program developed for the 2011 residential refrigeration products rulemaking . The test results, re verse engineering, vendor interviews, and manufacturer interviews provided input for the energy analysis. The incremental cost estimates and the energy modeling results together constitute the cost

- efficiency curves for cooled cabinets and non

- compressor r efrigerators presented in this chapter.

5.2.2 Ice Makers
For ice makers, DOE utilized the efficiency

- level approach , which calculates the relative costs of achieving increases in energy efficiency levels, without focus on to the particular design options used t o achieve such increases

. D OE developed costs for designs representing different efficiency levels using information sources and processes similar to those described above for cooled cabinets and non

- compressor refrigerators

. Efficiency levels for the anal ysis were based on energy test results for representative models of ice makers using the test procedure proposed in the 2014 MREF TP NOPR.5-4 5.3 DATA COLLECTION

DOE collected data from a number of sources to support the engineering analysis. The key sources include the following:

• Review of Previous Rulemaking TSDs , Product Literature, and Product Databases

• Energy Tests

• Manufacturer Interviews

• Component Vendors

• Reverse Engineering

The data collection process is described in greater detail in the following sect ions.

5.3.1 Review of Previous Technical Support Documents and Models , Product Literature,
and Product Databases

DOE reviewed the 2011 residential refrigeration product s rulemaking TSD and its associated spreadsheet models to assess their applica bility to the cu rrent standard

- setting process for miscellaneous refrigeration products

. Th is previous rulemaking TSD served as a re source for design options and energy consumption analysis.

In collecting energy consumption information and other product characteristics , D OE reviewed product literature from the websites of miscellaneous refrigeration product manufacturers. Because wine chillers are regulated products in California and Canada, DOE also consulted the databases of products certified to the CEC 2 and Natural Res ources Canada (NRCan) 3 to obtain energy use information for wine chillers (cooled cabinets)

.

5.3.2 Energy Tests
DOE conducted energy testing on cooled cabinets , non

- compressor refrigerators, and ice makers to verify the energy use of the products obtained for reverse engineering and to provide refrigeration system data to support energy use modeling. These tests served as the only source of energy consumption information for non

- compressor refrigerators and ice makers, because DOE proposed test procedure s for t hese products that have not been used previously. The proposed test procedure for non

- compressor refrigerators is similar to the existing refrigerator test procedure

. In addition to the energy use required to produce ice, the proposed test procedure for ic e makers includes the energy use associated with idle periods when ice is being stored but not used, including the energy use associated either with keeping the ice storage bin cold or with replenishing melted ice

.
DOE contracted with an independent test l ab to have tests conducted according to the test procedures proposed in the 2014 MREF TP NOPR

. In addition to providing measurements of5-5 energy consumption , DOE requested specific temperature measurements to be made in various locations during the test to b etter understand the refrigeration system operating characteristics. Specifically, low

- mass thermocouples were mounted in good thermal contact with the surface of refrigerant tubing or thermoelectric components , insulated externally from local ambient air in order to represent key refrigeration system temperatures

.

5.3.3 Manufacturer Interviews
DOE’s contractor discussed engineering issues with manufacturers of miscellaneous refrigeration products during the preliminary analysis interviews. DOE conducted these

e n gineering discussions using an engineering questionnaire, shown in appendix 5A , which guided the interview process. Key technical topics addressed during these discussions include the following:

• Typical characteristics of components and typical design det ails ( i.e.
, insulation thicknesses) used for each product type

.

• Typical design differences between baseline and high

- efficiency products

.

• Viability and typical costs of technology options.

During the interviews, DOE also gathered information about the capital expenditures required to increase the efficiency of the baseline units to higher efficiency levels. The interviews provided information about the magnitude and the nature of the require d capital investments. DOE also requested information about the depreciation method used to expense the conversion capital.

All of these interviews were conducted under non

- disclosure agreements with the participating manufacturers. Hence, none of the indi vidual responses can be reported. However, values for many of the parameters and costs used in the engineering analysis were based on aggregate d input from these discussions. Additionally, after developing initial engineering cost
curves, DOE asked manufac turers to provide feedback on the initial results of its cooled cabinet analysis. DOE adjusted its results based on this feedback.

5.3.4 Component Vendors

DOE also contacted major suppliers of key refrigeration product components to obtain performance and cost d ata to support its design option analysis. This vendor solicitation effort consisted of phone interviews, email correspondence, and in

- person interviews. DOE considered the information collected in developing key input parameters for manufacturing cost and energy models.5-6 5.3.5 Reverse Engineering

DOE finds that development of accurate cost estimates for a product is significantly enhanced by disassembl ing the product piece

- by

- piece and estimat ing the material and labor cost of each component using a process commo nly called a physical reverse engineering teardown. DOE purchased a number of representative cooled cabinets , non

- compressor refrigerators, and ice makers as part of the engineering analysis in order to examine design and fabrication details. Data collected from the teardowns w ere used as input to the manufacturing cost model for all three product types

, and to the energy use model for cooled cabinets and non

- compressor refrigerators . This section describes the rationale behind DOE’s selection of products for reverse engineering

, as well the measurements made to support subsequent modeling. Section 5.4 more thoroughly describes the physical teardown proce ss used to support manufacturing cost modeling.

5.3.5.1 Selection of Units

In selecting units for teardown, DOE generally attempts to choose products that span the full range of efficiency levels for each product class under consideration. Typically, these product s also come from manufacturers with the largest market shares

, and have features that are generally representative of the market

. DOE selected wine chillers to serve as representative products for cooled cabinets. Because vapor

- compression wine chillers ha ve energy consumption information publicly listed in the CEC and NRCan databases, DOE used these databases to select eight units that it deemed representative of vapor compression cooled cabinets based on the above criteria. Of these eight unit s , one was a small countertop unit (storage volume of ~2 ft 3 ), five were under

- counter units (~6 ft 3 ), and two were large, standard

- sized units (~1 6 ft 3 ). All of these products featured a single glass door, and all but the two standard

- sized units had a single controlled temperature zone. The two standard

- size units each had two independently

- controlled temperature zones. Figure 5.3

. 1 plots both the CEC ratings of DOE’s selections and the ratings of the other units in the CEC and NRCan wine chiller databases. As evidenced by this plot, DOE’s selected units span a wide range of capacity ( i.e.
, storage volume) and a wide range of efficiency levels compared to the

m aximum allowable energy consumption prescribed by the CEC.5-7 Figure 5.3

. 1 Vapor

- Compression Cooled Cabinets Selected for Teardown

DOE also selected three thermoelectric wine chillers for teardown to serve as representative units for its evaluation of thermoelectric cooled cabinets . As explained in the Framework Document 4 for this rulemaking, the language of the CEC regulations suggest s that their wine chiller standards apply to thermoelectric wine chillers. However, after the Framework meeting, DOE was unable to identify any thermoelectric units in the CEC database, which contains a complete list of all the products certified by manufacturers as satisfying the CEC energy conservation standards. This suggests that thermoelectric wine chillers may not meet California’s energy conservation standards. Moreover, manufacturers noted during the framework meeting that the CEC test procedure specifically mentions compressor cycles (see chapter 2 of this TSD), which suggests that manufacturers do not consi der the CEC standards to apply these products. Additionally, because the Canadian wine chiller test procedure specifically indicates that it does not apply to thermoelectric wine chillers, the NRCan database does not include any thermoelectric units.

Howe ver, DOE select ed units from all the major thermoelectric wine chiller manufacturers for reverse engineering teardown and testing . DOE still selected units spanning a range of sizes (0.6 ft 3 , 1 ft 3 , and 2 ft 3 ) in order to best represent the breadth of prod ucts on the market

. E ach of these units featured glass doors, and the 1 ft 3 unit featured two independently

controlled temperature zones, each with its own door.

DOE was unable to find publicly

- available efficiency information for non

- compressor refrigerat ors. DOE purchased and tested six models

, including five thermoelectric refrigerators5-8 and one absorption refrigerator. DOE conducted full reverse

- engineering on three of these models (two thermoelectric units and the absorption unit) that broadly represent ed the group of products

. Additionally, DOE was unable to find publicly

- available efficiency information for most ice makers . Although some manufacturers publish energy consumption information for their ice makers, these ratings are based on the DOE test p rocedure for automatic commercial ice makers, which differs from the ice maker test proposed by DOE . Therefore

, DOE selected two units from each product class that it has proposed in Chapter 3 of this TSD: portable ice makers ( IM

- P), cooled

- storage ice makers ( IM

- C), and uncooled

- storage ice makers ( IM

- U). The two products selected for each product class had approximately the same advertised harvest rate, and the selected products spanned four manufacturers.

5.3.5.2 Collection of Cooled Cabinet Energy Modeling Data

As discussed in section 5.2.1

, DOE developed energy consumption mode ls for cooled cabinets , as well as thermal load mode ls for non

- compressor refrigerators

. DO E used measurements and information collected for the cooled cabinet s and non

- compressor refrigerator s during the reverse engineering work as input for energy modeling. The following paragraphs describe these measurements

. DOE measured component

- level pow er input for fans , where present

. For vapor

compression products, DOE also made air flow measurements for all air

- cooled condensers using a hot wire anemometer. The location of these measurements varied depending on the heat exchanger type and configuratio n. The determination of air flows based on these measurements is not very precise , so DOE used this measurement as an indication of air flow trends rather than an exact indication of air flow for the various products.

DOE measured cabinet dimensions, heat exchanger dimensions, and insulation thickness for the reverse

- engineered cooled cabinets . DOE noted condenser details including type, configuration, numbers of tubes and fins, dimensions, and other information needed for energy modeling

. DOE similarly determined t he details of evaporators and suction line heat exchangers during teardown.

Finally, DOE recorded component manufacturer and model data for key components such as compressors, fans, and controls.5-9 5.4 MANUFACTURING COST M ODELING

5.4.1 Generation of Bill o f Materials

The end result of each reverse engineering product teardown is a structured bill of materials (BOM). Structured BOMs describe each component of a unit, and its relationship to the other components , in the estimated order of assembly

. The BOMs d escribe each fabrication and assembly operation in detail, including the type of equipment needed ( e.g. , stamping presses, injection molding machines, spot

- welders, etc .) and the process cycle times. The result is a thorough and explicit model of the produ ction process.

The BOMs incorporate all materials, components, and fasteners

, classified as either raw materials or purchased parts and assemblies. The classification into raw materials or purchased parts is based on DOE’s previous industry experience, re cent information in trade publications, and discussions with high

- and low

- volume original equipment manufacturers (OEMs).

For purchased parts, the purchase price is an estimate based on volume

- variable price quotations and detailed discussions with suppl iers. For parts fabricated in

- house

, the prices of “raw” metals ( e.g. , tube, sheet metal) are estimated on the basis of 5

- year averages

. For o ther “raw” materials such as plastic resins, insulation materials, etc. , prices are estimated on a current

market basis.

5.4.2 Cost Structure of the Spreadsheet Models

The manufacturing cost assessment methodology used is a detailed, component

- focused technique for rigorously calculating the manufacturing cost of a product (direct materials, direct labor and some overhead costs). Figure 5.4

. 1 shows the three major steps in generating the manufacturing cost.

Figure 5.4

. 1 Manufacturing Cost Assessment Stages

The first step in the manufacturing cost assessment was the creation of a complete and structured BOM from the disassembly of the units selected for teardown

. The units were dismantled, and each part was characterized according to weight, manufacturing processes used,5-10 dimensions, material

, and quantity. The BOM incorporates all materials, components, and fasteners with estimates of raw material costs and purchased part costs. Assumptions on the sourcing of parts and in

- house fabrica tion were based on industry experience, information in trade publications

, and discussions with manufacturers. Interviews and plant visits were conducted with manufacturers to ensure accuracy on methodology and pricing.

The last step was to convert this information into dollar values. To perform this task, DOE collected information on labor rates, tooling costs, raw material prices, and other factors. DOE assumed values for these parameters using internal expertise and co nfidential information available to DOE contractors.

In summary, DOE assigned costs of labor, materials, and overhead to each part, whether purchased or produced in

- house. DOE then aggregated single

- part costs into major assemblies ( e.g. , heat exchanger a ssembly, packaging, controls, fan/motor assembly, refrigerant circuit, and wiring harnesses) and summarized these costs in a worksheet.

Design options used in units subject to teardown were noted in the summary sheet of each cost model and DOE estimated t heir cost s individually. Thus, various implementations of design options can be accommodated, ranging from assemblies that are entirely purchased to units that are made entirely from raw materials. Hybrid assemblies, consisting of purchased parts and parts made on site

, are thus also accommodated.

5.4.3 Cost Model and Definitions
Once DOE disassembled selected units, and identified technologies, DOE created an appropriate manufacturing cost model that could translate physical information into manufacturing produc tion costs

. The cost model is based on production activities and divides factory costs into the following categories:

• Materials: Purchased parts ( i.e.
, fan motors

, compressors , etc .), raw materials, ( i.e. , cold rolled steel, copper tube, etc .), and indirect materials that are used for processing and fabrication.

• Labor: Fabrication, assembly, indirect, and supervisor labor. Fabrication and assembly labor cost are burdened with benefits and supervisory costs.

• Overhead: Equipment, tooling, and building depreciation, as well as utilities, equipment and tooling maintenance, insurance, and property taxes.

Because there are many different accounting systems and methods to monitor costs, DOE defined the above terms as follows:

• Direct material: Purchased parts (out sourced) plus manufactured parts (made in

- house from raw materials).

• Indirect material: Material used during manufacturing ( e.g. , welding rods, adhesives).5-11 • Fabrication labor: Labor associated with in

- house piece manufacturing.

• Assembly labor: Labor as sociated with final assembly.

• Indirect labor: Labor costs that scaled with fabrication and assembly labor

. This included the cost of technicians, manufacturing engineering support, stocking, etc . that were assigned on a span basis.

• Equipment and plant depr eciation: Money allocated to pay for initial equipment installation and replacement as the production equipment is amortized

.

• Tooling depreciation: Cost for initial tooling (including non

- recurring engineering and debugging of the tools) and tooling replac ement as it wears out or is rendered obsolete

.

• Building depreciation: Money allocated to pay for the building space and the conveyors that feed and/or make up the assembly line.

• Utilities: Electricity, gas, telephones, etc

.

• Maintenance: Annual money spent on maintaining tooling and equipment.

• Insurance: Appropriated as a function of unit cost.

• Property Tax: Appropriated as a function of unit cost.

5.4.4 Cost Model Assumptions
As discussed in the previous section, assumptions about manufacturer practices and cost structure played an important role in estimating the final product cost

. In converting physical information about the product into cost information, DOE reconstructed manufacturing processes for each component using internal expertise and knowledge of the methods used by the industry

. DOE used assumptions regarding the manufacturing process parameters ( e.g. , equipment use, labor rates, tooling depreciation, and cost of purchased raw materials) to determine the value of each component

. DOE then summed the values of the components into assembly costs and, finally, the total product cost

. The product cost included the material, labor, and overhead costs associated with the manufacturing facility

. The material costs included both direct and indirect materials

. The labor costs included fabrication, assembly, indirect, direct, and supervisor labor rates, including the associated overhead. The labor costs were determined by the type of product manufactured at the factory

. Overhead costs included equipment deprecia tion, tooling depreciation, building depreciation, utilities, equipment, tooling maintenance, i nsurance, property, and taxes.

5.4.4.1 Fabrication Estimates
DOE characterized parts based on whether manufacturers purchased them from outside suppliers or fabricated them in

- house. For purchased parts, DOE estimated the purchase price. For fabricated parts, DOE estimated the price of raw materials ( e.g. , tube, sheet metal) and the cost of transforming them into finished parts. Whenever possible, DOE obtained price quot es directly from the manufacturers’ suppliers.5-12 DOE based the manufacturing operations assumptions on internal expertise, interviews with manufacturers, and manufacturing facilities sit e visits. The major manufacturing processes identified and developed fo r the spreadsheet model are listed in Table 5

. 1 . Fabrication process cycle times were estimated and entered into the BOM.

Table 5

. 1 Cost Model In

- House Manufacturing Operation Assumptions Fabrication Finishing Assembly/Joining Quality Control Fixturing Stamping/Pressing Turret Punch Tube Forming Machine Cutting & Shearing T

- Drill Tube/Wire Bending Brazing Vacuum Forming Blow Molding Washing Painting Powder Coating De

- Burring Polishing Refrigerant Charging Adhesive Bonding Spot Welding Seam Welding Packaging Inspecting & Testing

5.4.4.2 Factory Parameters Assumptions
DOE used information gathered from publicly available literature, manufacturer interviews, and analysis of common industry practices to formulate factory parameters for each type of manufacturer. DOE first made assumptions about a set of preliminary factor y parameters before the manufacturer interviews. DOE then revised the assumptions using comments and information gathered during the interviews. Table 5

. 2 lists DOE’s assumptions for cooled cabinet , non

- compressor refrigerator, and ice maker manufacturers.

Table 5

. 2 Factory Parameter Assumptions P arameter Cooled Cabinet , Non

- Compressor Refrigerator, and Ice Maker Assumption Plant Capacity (units/yr) 25,000 Actual Annual Production Volume (units/yr) 20,000 Fabrication Labor Wages ($/hr) $16 .00 Fringe Benefits Ratio 0.55-13 5.4.4.3 Material Cost Assumptions
DOE determined the cost of raw materials using publicly available information such as the American Metals Market, 5 interviews with manufacturers, and direct discussions with material suppliers. Common metals used in the fabrication of refrigeration products include cold rolled steel, stainless steel, copper tubing, and aluminum. There have been large fluctuations in metal prices over the last few years. To account for these fluctuations, DOE used a 5

- year average of metal prices from the Bureau of La bor Statistics Producer Price Indices (PPIs) spanning from 2008 to 2013 with an adjustment to 2013 dollars ( 2013 $). 6 DOE used the PPIs for copper rolling, drawing, and extruding and steel mill products, and made the adjustments to 2013 $ using the gross domestic product implicit price deflator. 7 For resins used in the fabrication of these refrigeration products, DOE used current resin prices gathered from industry research, publications such as Plastics News, 8 and interviews with manufacturers.

In order t o assure that the raw material prices DOE used in manufacturing cost estimates are representative of actual costs paid by OEMs, DOE sent a material cost questionnaire to the manufacturers that participated in the technical interviews.

5.4.4.4 Inflation Adjustment

As discussed further in section 5.6 , DOE used some cost data from the 2011 refrigeration products rulemaking in developing purchased parts cost estimates for this engineering analysis. To adjust these costs from 2011$ to 2013$, DOE multiplied the 2011 costs by a ratio of the producer price index (PPI) for each year. For fan motors, this ratio was equal to 1.07, and for compressors, it was equal to 1.26

.

5.4.5 Manufacturin g Production Cost
After finalizing the cost estimate for each teardown unit, DOE prepared a detailed summary for relevant components, subassemblies, and processes. The BOM thus details all aspects of product costs. DOE totaled the cost of materials, labor, and direct overhead used to manufacture a product in order to calculate the manufacturing production cost. Figure 5.4

. 2 shows the general breakdown of costs associat ed with manufacturing a product. a

a When viewed from the companywide perspective, the sum of all material, labor, and overhead costs equals the company’s sales cost, also referred to as the cost of goods sold.5-14 Figure 5.4

. 2 Full Production Costs

The full cost of the product is equal to the manufacturer selling price (MSP) minus profits. The full cost includes the MPC and the non

- production cost.

5.4.6 Incremental Cost Estimates
Incremental costs were determined for design options and were applied to the estimated cost of the baseline

- efficiency cooled cabinets , non

- compressor refrigerators, and ice makers

. The approach for estimatin g the incremental costs varied depending on the design option. Details in this calculation that are specific to individual design options are discussed in sectio ns 5.7, 5.8 and 5.9. Aspects of the incremental cost calculation that were generally applied to multiple design options are discussed in this section.

Many of the design options involve replacement of a current component with a higher

efficiency component. For these design options, the increased price paid by the OEM for the new component represent s the manufacturing cost increase, because other elements of product cost5-15 such as overhead and capital expenditures would be insignificantly affected by these design changes. The price increases are discussed in section 5.8 by design option.

For some desi gn changes, calculating the cost impact of the design change required direct use of the manufacturing cost model to determine changes to a number of parts. DOE subtracted
t he baseline manufacturing cost from the manufacturing cost of the modified design to determine the incremental cost of the design option. DOE used t his approach in particular for insulation thickness increases.

5.4.7 G&A and Profit
DOE estimated the further addition to the MSP associated with general and administrative costs (G&A) and profit fo r the appliance industry as percentages of MPC for each product type.

For the preliminary analysis, DOE usually develops this manufacturer markup multiplier by examining the annual reports and Securities and Exchange Commission (SEC) 10

- K filings of

sever al major manufacturers. Because the 10

- K reports do not provide gross margin information at the subsidiary or business unit level, DOE scaled the gross margin figures from the 10

- K reports by the percentage of the companies’ overall revenue that is attribu table to the particular product segment containing consumer refrigeration products.

Following preliminary interviews with manufacturers, DOE adjusted market share estimates for the industries covered in this rulemaking. Then, using the financial data of several publically

- traded manufacturers, DOE calculated separate market share

- weighted average markups for the following product categories : vapor

- compression cooled cabinets, thermoelectric cooled cabinets and non

- compressor refrigerators

, and ice makers . The markup for ice makers represents all ice maker product classes and has not been s eparately evaluated for each class . The calculated markup s are 1.26, 1.22, and 1.23, respectively for vapor

- compression cooled cabinets, thermoelectric cooled cabinets and non

- compressor refrigerators, and ice makers

. Markups are explained further in Chapt er 6 of this TSD.

5.5 ENERGY MODELING
DOE carried out energy modeling of representative cooled cabinets and on design variations of these products that included one or more of the efficiency

- improving design options considered for the engineering analysis. Thi s energy modeling work provided a basis for developing estimates of the energy savings potential associated with cooled cabinet desig n configurations for which test data were not available. Energy model input s , detailed in a ppendix 5A, were determined for these products from the data collected during the reverse engineering work, described in s ection 5.3.5.2

. Additional data, used both as input and for calibration of individual product energy models, were provided by energy testing as described in section 5.3.2

.5-16 The energy modeling results and manufacturing cost modeling results for these designs allowed DOE to develop incremental cost estimates for multiple efficiency levels based on the baseline
pr oduct analyzed.

DOE also used energy modeling as part of its engineering analyses for non

- compressor refrigerator s and for hybrid refrigeration products. The analysis methodology for non

compressor refrigerators is described in section 5.8 , and the methodology for hybrid refrigeration product s is described in section 5.10

.
DOE used the ERA simulation program to develop t he energy models for this rulemaking effort . This program has been updated since its use in the 2011 residential refrigeration products rulemaking

, to include the ability to model glass doors and warmer compartment temperatures

. Section 5.5.1 describes this model briefly. A more detailed description of the program and its recent development is presented in appendix 5B

.

5.5.1 ERA Model Overview
ERA is a steady

- state energy model that calculates heat leakage into a cabinet and determines the energy needed by the refrigeration system to maintain the interior temperatures as specified by the user. Total energy used includes the energy from the compressor, fan motor(s)

, defrost heater, and electronic control s , if applicable. See appendix 5 B for a detailed explanation of the ERA model.

ERA combined an analysis of the refrigeration load requirements of the cabinet with a simulation of the capacity and efficiency of the refrigeration cycle. The DOS version of ERA

wa s developed initially under U.S. Environmental Protection Agency ( EPA ) spon sorship during the late 1980s. 9

The program and its User’s Manual were first released to the public in 1993, after extensive review and comparison against test data, and for a few years were downloadable from the EPA website. 10 Subsequent to the 1993 final rule, DOE published updated standards for refrigerators, refrigerator

- freezers and freezers in 1997, becoming effective in 2001. 62 FR 23102 (April 28, 1997) Analysis carried out in support of the 1997 final rule involved use of the final released EPA ver sion of ERA.

The DOS version of ERA was subsequently modified as described in appendix 5B, but these revisions were not made available to the public. During the course of the 2011 rulemaking, further development of the model was carried out in order to all ow use of the model for calculation of energy use of modern consumer refrigeration products and to allow a modern version of the program to be made available to stakeholders to validate DOE analysis. Key modifications made include enhancement of the user i nterface to a Windows environment, as well as many modeling improvements that are described further in the 2011 rulemaking TSD.5-17 Additional modifications were made to ERA during the course of this rulemaking in order to make it more appropriate for modelin g wine chillers rather than just conventional refrigeration products. These modifications include the following:

• Ability to set compartment temperatures as warm as 55 °F, the standardized temperature set forth in DOE’s proposed test procedure for wine chil lers

.

• Ability to model glass doors by inputting an overall U

- value

. The development history and capabilities of the program are describ ed in more detail in appendix 5 B.

5.5.2 Development and Calibration of ERA Models

ERA cooled cabinet modeling during the engi neering analysis involved the following two phases :

• Modeling of existing baseline, medium

- efficiency , and max

- available reverse

- engineered products based on the current energy test procedure. These three units were used to generate the cost

- efficiency curv e, as described in s ection 5.6 , and were all approximately 6 ft 3 in volume.

• Iterative modeling with multiple series of adjustments to calculate the energy savings that can be achieved with different combinations of design options.

This section focuses on the first phase of the ERA modeling work: establishing models for the teardown products based on the proposed energy test procedure. DOE compared t he teardown product analysis results with energy test data to assure that t he models provide d accurate representation of product energy use. This section discusses the creation and calibration of the ERA energy models, the metrics which were compared, and the adjustments which were made in some cases in order to improve calibrati on.

DOE collected i nput data for energy modeling during the reverse engineering phase of the project , as discussed in s ection 5.3.5.2 above. T he energy tests provi ded additional information for certain model input parameters, such as the number of compressor cycles per hour

.
DOE created i nitial energy models and subsequently adjusted them to provide a best match with available data for product energy performance fr om the energy tests of the rever se

engineered units (s ection 5.3.2 ). In addition to energy use , DOE also used test data on compressor running power input, duty cycle, evaporating temperature, and condensing temperature to calibrate the models

. Because not all ERA input parameters can be determined definitively based on available information, some of the inputs were adjusted within reasonable ranges in order to pr ovide good matches between model results and other performance indicators.5-18 DOE estimated the thermal performance of the glass doors found in most cooled cabinet s using WINDOW 6 software available from Lawrence Berkeley National Laboratory. WINDOW

, whose s oftware and user manual are publicly available, 11 is a Microsoft Windows

- based computer program used to determine the thermal and optical properties of glazing and window systems for residences and buildings. WINDOW is used as part of the process by which

m anufacturers of windows, doors, and skylights certify their products to the National Fenestration Rating Council. 12 T he program has also been used successfully to model the thermal performance of glazed surfaces for refrigerat ed cabinets

. DOE input details about each cooled cabinet’s glass door, including thickness, number of panes, and presence of low

- e coating or inert gas insulation, and received the door’s overall U

- value (thermal conductance in W/m 2

- K) as an output to use directly in ERA.

In some cases, DOE concluded that ERA was not modeling particular heat exchangers

– specifically, cold

- wall evaporators

– properly

. In these cases, DOE adjusted the calculated effective surface area of the heat exchanger upwards to represent heat transfer performance di fferent than modeled to achieve more reasonable match of evaporating or condensing temperatures, as well as energy use, as measured during energy test work.

Table 5

. 3 compares t he calibrated ERA analysis results for the analyzed baseline, medium

- efficiency , and max

- available cooled cabinets with the energy test results. DOE adjusted t he modeled energy use of these units consistent with the proposed cooled cabinet test procedure by applying the 0. 55 correction factor for cooled cabinets (see section 2.3.6 of this TSD for further details on this correction factor) . The energy consumption results from ERA are within one percent of the energy test results

.
Table 5

. 3 Comparison of ERA Results and Test Results for Vapor

- Compression Cooled Cabinets

Unit Energy Use (kWh/year) Duty Cycle Av era g e On

- Cycle Compressor Power (W) Tested Modeled Tested Modeled Tested Modeled Baseline 310 311 0.701 0.650 8 7 93 Medium

- Efficiency 206 206 0.286 0.271 125 130 Max

- Available 104 103 0.193 0.219 95 865-19 5.6 COOLED CABINET AND N ON

- COMPRESSOR REFRIGERA TOR DESIGN OPTIONS
After conducting the screening analysis described in Chapter 4 of this TSD , DOE considered the remaining technologies in the design option analysis for cooled cabinets and non

compressor refrigerators. Table 5

. 4 lists the design options DOE considered for these two product types. Following the table is a description of how DOE applied each of the design options in the engineering analysis. See Chapter 3 of this TSD for background descriptions of the technologies and Chapter 4 of this TSD for an explanation of why some technologies were screened out for one product class but not for the other

.
Table 5

. 4 Design Options Design Option Considered for Cooled Cabinets Considered for Non

Compressor Refrigerators Brushless DC Condenser Fan Motor 
Conversion to Vapor Compression 
Heat Pipe  Increased Insulation Thickness   Improved Compressor Efficiency 

Forced

- Convection Evaporator  Improved Glass Door Resistivity  Variable

- Speed Compressor  Vacuum

- Insulated Panels  

5.6.1 Brushless DC Fan Motors
Brushless DC fan motors are more efficient than the shaded pole motors which are often used in medium

- efficiency cooled cabinets. Consistent with its methodology in the 2011 refrigeration TSD, DOE assumed a power reduction of 50 percent for brushless DC (BLDC)
motors as compared with shaded

- pole motors

. 1

During the 2011 residential refrigeration products rulemaking, DOE obtained incremental cost estimates for the switch to brushless DC motors

. For cooled cabinets, DOE used an incremental cost estimate of $4.40 for evaporator and condenser fans, which is the 2011 incremental cost estimate for refrigerator evaporator fans inflated to 2013 dollars. 1 DOE applied this incremental cost estimate for bo th evaporator and condenser fans.5-20 5.6.2 Insulation Thickness

Manufacturers stated during discussions that the potential for insulation thickness increases is very limited for cooled cabinets, some of which are designed as “built

- in” products, intended exclusivel y to be fastened to adjacent cabinetry upon installation. (See 10 CFR 430.2 for the definition of “built

- in” refrigeration products.) Increasing insulation thickness would decrease interior volume, increase exterior dimensions, or cause some combination of both. The maximum insulation thickness observed during teardown of under

- counter and built

- in cooled cabinets was 2 inches. This suggests that acceptable interior volumes can be maintained in an under

- counter or built

- in cabinet using 2

- inch insulation. Hence, DOE considered increase s in insulation thickness up to this level.

DOE modeled this design option by directly increasing both the insulation thickness and the overall cabinet external dimension inputs in its energy model, maintain ing interior volume. DOE directly calculated the cost increase using its manufacturing cost model.

5.6.3 Vacuum

- Insulated Panels

Vacuum

- insulated panels (VIPs) increase efficiency by significantly increasing the thermal resistivity of the cabinet walls, therefore decreasing heat penetration into the cabinet. DOE considered the addition of half

- inch thick VIPs to the walls and doors of the cabinet for all product classes, in which case the remainder of the insulation thickness would be filled with polyurethane foam. The data and approach DOE used to analyze the costs and thermal impacts of VIPs are identical to those that it had used in the 2011 rulemaking and are described in the TSD for that rulemaking.

In discussions with manufacturers d uring the 2011 refrigeration product rulemaking’s NOPR phase, DOE learned that different manufacturers had widely varying levels of success in appl ying VIPs to refrigeration products. The levels of performance benefit reported by manufacturers ranged roughly from 0 to 100 percent of the levels predicted by the ERA analysis. DOE used a performance degradation factor of 50 percent in its analysis to ac count for this variation in experience. However, DOE notes that none of this manufacturer feedback specifically addressed cooled cabinets, and that manufacturers indicated that VIPs provide less performance enhancement for fresh food compartments than they do for freezer compartments. Consequently, the information obtained regarding VIPs may not extend to compartments operated at 55  ̊F. DOE requests data showing thermal performance for such compartments using VIPs

— see the executive summary of this TSD

.
DOE used the same methodology and assumptions, with costs inflated from 2011$ to 2013$, that were used in the 2011 residential refrigeration products rulemaking to calculate the VIP costs for cooled cabinets.5-21 5.6.4 Improved Compressor Efficiency

For cooled cabinets

– most of which use compressors with capacities between 300 and 400 Btu/hr

– DOE considered the use of a higher efficiency compressor in place of the baseline
compressor . DOE acquired performance data from compressor vendors for use in the energy analysis, including capacity and power input for the applicable range of combinations of suction and discharge pressure conditions.

As an example of the potential for improvement, wine chillers typically use compressors with a rated energy efficiency ratio ( EER ) o f 3.0 to 4.0 Btu/h

- W. DOE considered an improved EER of 4.9 Btu/h

- W, the maximum efficiency available in the above capacity range. This higher efficiency compressor would reduce a cooled cabinet’s electricity consumption but still provide the same refriger ation capacity as the compressors that are typically being used in current models.

During the 2011 refrigeration products rulemaking, DOE received vendor cost estimates for higher

- efficiency low

- capacity compressors

. DOE obtained additional information dur ing discussions with manufacturers of products which use these compressors. DOE used a representative cost estimate of $10 per 1.0 Btu/h

- W efficiency improvement in the analysis for the 2011 rulemaking for compressors with capacities less than 600 Btu/h. 1 For the cooled cabinet analysis, DOE increased this cost to $12.60 per 1.0 Btu/h

- W to account for inflation.

5.6.5 Variable

- Speed Compressor

Variable

- speed compresso rs (VSCs) operate at multiple speeds to allow variation of compressor capacity. Currently

, many products containing variable

- speed technology use Embraco VSCs. DOE obtained compressor performance data for the range of sizes of Embraco VSCs and used this in formation in the energy analysis.

In order to maximize the energy benefit of a VSC, a design needs to address the potential increase in energy use associated with longer fan run time. The increase in fan energy use can negate much of the reduction in comp ressor energy use. As a result, it is often necessary to use brushless DC fan motors.

In addition, brushless DC fan motors can operate at different speeds, depending on the design configuration. DOE is not aware of brushless DC fan motors designed for 120 VAC power input at representative capacities for refrigerator duty that allow adjustment of fan speed, although such a design should be viable. Most designs incorporating fan speed control use DC

input power for the fans and require a control system which provide s the DC power

, and var ies it to adjust fan speed. DOE’s analysis did not involve optimization of fan speed and power with the VSC system.
During the 2011 residential refrigeration products rulemaking, DOE obtained from Embraco

, and from discussions with refrigeration product manufacturers

, estimates of the cost5-22 increase for switching to VSCs . An average of the estimates provided by the manufacturers

, weighted by manufacturer market share

, was near $56. 1 This include d the compressor and its motor controller, but did not include additional changes which might be required to implement a VSC . DOE inflated this to current dollar values and used a $59 cost increase in the analyses. Additional costs associated with conversion of a refrigeration system to variable

- speed operation include a switch to brushless DC fan motors

, and the use of a control system sophisticated enough to provide adequat e or optimized control.

The Embraco VSC design includes a control system that can be used with a conventional mechanical thermostat. This system has been implemented in a commercially available freezer. 13 The Embraco control adjusts speed based on the resp onse of the mechanical thermostat. For its analysis, DOE consider ed this approach suitable for cooled cabinets . DOE also considered use of brushless DC fan motors necessary when switching to VSCs. However, the DOE analysis incorporated a switch to brushles s DC fan motors as a design option earlier than VSCs in the progressive layering of design options, because brushless DC fan motors are more cost

- effective than a full conversion to variable speed. DOE also considered the additional standby power consumpti on associated with the electronic control board required for conversions to variable

speed operation. DOE attributed 1.5 W of standby power to these electronic controls. The energy model also adjusted the number of cycles per hour when applying a VSC

, to r educe the off

- cycle loss calculated for the refrigeration system

.

5.6.6 Forced Convection Evaporator
Many low

- and medium

- efficiency cooled cabinets feature a flat, vertical roll

- bond evaporator mounted on the rear cabinet wall. A forced convection evaporator can be more efficient than such a roll

- bond evaporator

, because it enables more effective heat transfer from the refrigerant to the cabinet. DOE’ s analysis of converting to a forced convection evaporator as a design option includ es the following design cha nges: the replacement of a roll

- bond or coldwall evaporator with a fin

- tube evaporator, a fan assembly, and wiring to power the fan, as well as the elimination of the roll

- bond evaporator plate. In calculating the net incremental cost for this conversion, DOE assumed the use of a brushless DC fan motor.

5.6.7 Improved Glass Door Resistivity
Heat loss through the door can account for a substantial portion of the thermal load in cooled cabinets, which typically use double

- pane glass doors. By i mproving the resistiv ity of the glass pack, which consists of the glass pane(s) and the air or gas enclosed by the panes, the heat transfer through the door can be significantly decrease d. DOE examined two different design options related to increasing glass door resistivity. The first, which DOE termed the “medium

tech” glass door, consists of a double

- pane glass door with low

- e coating on both panes and argon gas filling the gap between them. To DOE’s knowledge, this is the door technology with the highest thermal resistivity available in cooled cabinets that are currently commercially5-23 available. The second design option, which DOE termed the “max

- tech” glass door, consists of a triple

- pane glass door with low

- e coating and krypton gas filling.

DOE obtained performance metrics for these door design options by modeling them in WINDOW 6, as described in section 5.5.2 . DOE then used the U

- values output by WINDOW as a direct input for ERA. T he U

- values used for the different door designs are presented in Table 5.5. The inputs used to generate these U

- values in WINDOW are described in appendix 5A.

Table 5

. 5 Glass Door Design Options Door Design O ption Description U

- value (W/m 2

- K) Baseline 2

- pane, no coating, air filling 3.044 Medium

- Tech 2

- pane, low

- e coating, argon filling 1.709

Max

- Tech 3

- pane, low

- e coating, krypton filling 1.143

DOE consulted with glass door manufacturers to obtain cost estimates for these different door design options. Based on these discussions, DOE used for its analysis a cost of $100 for a 4.2 ft 2 baseline door, an incremental cost of $12 for the medium

- tech door, and an additional incremental cost of $18 for the max

- tech door , yielding an overall incremental cost of $30 over the cost of the baseline door for the max

- tech door.

One potential concern of proposing the replacement of a double

- pane door with a triple

pane door is that the hinges currently used by cooled ca binets may be unable to support the extra weight of the additional glass pane. Based on the teardown analysis performed by DOE, a typical glass door for a compact

- sized cooled cabinet weighs approximately 25 pounds, and the addition of a third glass pane would increase the total weight of the door to approximately 31 pounds. Moreover, based on DOE’s reverse

- engineering analyses, the hinges found on most compact cooled cabinet doors are similar in size, composition, and structure to the hinges found on the compact refrigerator doors analyzed in the 2011 residential refrigeration rulemaking

. Because compact refrigerator doors are designed to support the weight of both the door and beverages stored in the door’s shelves, DOE does not expect the modest weight a ddition for a triple

- pane door to be a significant mechanical design issue for the hinges that would have to support the additional weight . Hence, DOE did not use concerns about hinge loads as a reason to reject the triple

- pane door design option.

5.6.8 Conversi on to Vapor Compression
As discussed in Chapter 3 of this TSD, vapor compression is a more efficient refrigeration technology than thermoelectric or absorption refrigeration. While, for this rulemaking effort, DOE analyzed cooled cabinets at volumes of 2 f t 3 and 6 ft 3 , the maximum capacity of non

- compressor cooled cabinets available for sale was found to be roughly 2 ft 3

. Hence, DOE considered baseline designs using thermoelectric or absorption technology and5-24 potential conversion to vapor compression as a d esign option only for the 2 ft 3 cooled cabinet analysi s

.
DOE based the cost of converting to vapor

- compression refrigeration technology on its manufacturing cost model s for the refrigeration system in reverse

- engineered 2 ft 3 cooled cabinets

– one using t hermoelectric

, and the other vapor

- compression refrigeration technology. The calculation includ ed the costs of the heat exchangers, refrigerant tubing, and a baseline compressor. DOE estimated this incremental conversion cost as $65.

5.6.9 Heat Pipe

DOE is aware that some thermoelectric refrigerators use a heat pipe to facilitate passive heat transfer on the “hot side” of their thermoelectric modules. Therefore , DOE considered the addition of a heat pipe as a design option for thermoelectric (non

- comp ressor) refrigerators

. DOE used its manufacturing cost model to estimate the costs associated with the addition of a heat pipe. Because DOE’s reverse

- engineered unit containing a heat pipe also featured two hot

- side fans, the calculated incremental costs for the use of a heat pipe, also included the cost of a secondary hot

- side fan.

5.7 COOLED CABINET ANALY SIS AND RESULTS

As mentioned in s ection 5.2 , DO E adopted a combined efficiency

- level/design

option/reverse

- engineering approach to developing cost

- efficiency curves for cooled cabinets. DOE established efficiency levels expressed as percent of CEC

- e quivalent energy consumption (as defined in s ection 5.7.1 ) . DOE’s analysis is based on the efficiency improvements associated with groups of design options (as described in s ection 5.7.3. Also, DOE developed manufact uring cost models based heavily on reverse engineering of products to support calculation of the incremental costs associated with improvement of efficiency. The following sections describe the details and results of this analysis.

5.7.1 CEC

- Equivalent Efficienc y Level

DOE ’s proposed test procedure for cooled cabinets is almost identical to the wine chiller test procedure established by CEC as part of its Title 20 Appliance Efficiency Regulations. 14 DOE’s proposed test differs from the CEC test procedure only in the application of a usage adjustment factor of 0.55 rather than the 0.85 used by the CEC . Consequently, DOE chose to express the baseline , and subsequent efficiency level s as a percentage of the equivalent CEC regulation ( the CEC wine chiller stan dard s multiplied by 0.55 and divided by 0.85 )

. This baseline efficiency level

, express e d as annual energy consumption as a function of volume, is presented in Table 5

. 6

. As explained in Chapter 3, DOE ’s cooled cabinet analysis is focused5-25 solely on units with automatic, rather than manual, defrost. Therefore, DOE use d the CEC standard for wine chillers with automatic defrost as the basis for its cooled cabinet baseline efficiency level.

Table 5

. 6 Cooled Cabinet CEC

- Equivalent Efficiency Level Energy Consumption Appliance Baseline Efficiency Level Annual Energy Consumption (kWh)

Wine chillers with automatic defrost (0.55/0.85)*( 17.4V + 344 ) = 11.3V + 223 V = volume in cubic feet.

DOE used this efficiency level as a point of comparison for its energy test results, as described in s ection 5.7.2

. In this document, cooled cabinet efficiency is presented as a percent of CEC

- e quivalent energy consumption; in other words, a cooled cabinet which exactly meet s the CEC energy standard has an efficiency level equal to 100 percent

. This is called CEC

e quivalent because the energy use in kWh is not the same as that specified by the CEC energy standard, due to the use of a different usage adjustment factor for the proposed DOE test. Likewise, cooled cabinet s with lower energy consumpti on have efficiency levels that are less than 100 percent. DOE chose this approach rather than representing efficiency levels as percentages of energy consumption at the baseline

, because manufacturers have st ated that the CEC Standard is a de

- facto market baseline.

5.7.2 Energy Test Results

5.7.2.1 Vapor

- Compression Cooled Cabinets

DOE tested and tore down eight vapor

- compression wine chillers for its cooled cabinet analysis. Of these wine chillers, as described further in s ection 5.3.5.1

, one was a compact countertop unit (approximately 2 ft 3 of storage volume), five were under

- counter units (approximately 6 ft 3 ), and two were “standard

- sized” units (approximately 16 ft 3 ). As shown in Table 5

. 7 below, the energy use measured for most of these wine chillers was lower than their CEC ratings, although one used more energy than its rating.

Table 5

. 7 also shows the average of the rated and test energy consumption for each
vapor

- compression cooled cabinet. Because of the disparity between the CEC ratings a nd energy test results for many of these units, DOE selected energy use equal to the average of the rating and the measurement to represent most of the units for subsequent analysis. Although DOE feels that the measurements represent an indication of the p otential efficiency level of the product, DOE acknowledges that there may be variations in manufacturing and in test results, and is being conservative in its use of the average values. Note that the percent of CEC s tandard levels presented for the tested units in the table are identical to their CEC

- equivalent efficiency level representations in percentages.5-26 Table 5

. 7 Vapor

- Compression Cooled Cabinet Energy Ratings vs. Test Results Storage Volume (ft 3 ) Rated E nergy Consumption (kWh/y ea r) 1 Rated % of CEC Standard Tested Energy Consumption (kWh/y ea r) Tested % of CEC Standard Average Energy Consumption (kWh/year) Average % of CEC Standard 1.7 206 87 % 131 54 % 167 7 0% 5.9 229 8 0% 206 71 % 218 7 5% 5.7 285 99 % 310 10 8% 298 10 3% 5.4 226 8 0% 147 52 % 187 66 % 5.9 284 10 0% 173 6 0% 229 8 0% 5.9 170 6 0% 104 36 % 137 48 % 15.4 342 86 % 233 59 % 288 72 % 17.3 243 57 % 237 57 % 240 57 %

1 From the CEC database: http://www.appliances.energy.ca.gov/AdvancedSearch.aspx , adjusted to account for the usage factor difference between the CEC test procedure and the proposed DOE test procedure.

5.7.2.1 Non

- Compressor Cooled Cabinets

As described in s ection 5.3.5.1

, DOE also tested and reverse engineered three non

compressor (thermoelectric) wine chillers. DOE’s pr oposed test procedure for non

- compressor cooled cabinets differs from its proposed test procedure for vapor

- compression cooled cabinets ( and the CEC’s wine chiller test procedure ) in that it involves testing at an ambient test temperature of 72 °F

, rather than 90 °F , and a usage adjustment factor of 1.2

, to represent the impacts of door openings in field operation at 72 °F. The proposed cooled cabinet test procedures are designed to allow direct comparison of test results for vapor

- compression and

non

- compressor cooled cabinets, thus allowing use of the CEC

- e quivalent percentages to represent efficiency levels for both types of products.

DOE ’s testing shows that the energy use of thermoelectric cooled cabinets can be much highe r than the CEC

- e quivalent energy use . As shown in Table 5

. 8 , which displays these test results, the percent CEC

- e quivalent energy use of the three thermoelectric coole d cabinets tested by DOE increased with increasing volume.

Table 5

. 8 Non

- Compressor Cooled Cabinet Tested Energy Use Storage Volume (ft 3 ) Tested Energy Consumption (kWh/year) % of CEC

Equivalent Energy Consumption 0.64 142 62 % 1.08 439 187 % 2.26 663 267 %

As described in Chapter 3 of this TSD, DOE is proposing to consider vapor

- compression and non

- compressor cooled cabinets in the same product class.5-27 DOE developed cost

- efficiency curves for 2 ft 3 and 6 ft 3 cooled cabinets. Because DOE is not aware of any non

- compressor cooled cabinet products significantly larger than 2 ft 3 , the 6 ft 3 analysis does not consider efficiency levels associated with non

- compressor refrigeration technology.

5.7.2.1 Active Defros t Cooled Cabinets

DOE initially considered establishing a separate product class for cooled cabinets with active heater defrost (as opposed to passive, or off

- cycle, defrost). As mentioned in Chapter 3, DOE is not aware of many cooled cabinets that have su ch active defrost. DOE tested one such unit in order to determine the contribution of the active defrost feature to the overall energy consumption of the unit. The test results showed that the defrost heater accounted for approximately 1.5 percent of the product’s overall energy consumption. This relatively small contribution, combined with DOE’s conclusion that such units represent a very small portion of the overall cooled cabinet market, has led DOE to analyze active defrost cooled cabin ets in the same product class as passive defrost cooled cabinets, as noted in Chapter 3 of this TSD

.

5.7.3 Efficiency Levels
When proposing efficiency levels for products, DOE first selects a baseline efficiency level as a reference point , against which DOE measure s changes resulting from the implementation of energy

- saving design options

. The baseline efficiency level for each product type represents the efficiency associated with the basic characteristics of products in that category

. Typically, a baseline efficiency level is equal to the current required energy conservation standard. However, because there are currently no federal energy conservation standards for cooled cabinets, DOE selected a baseline efficiency level that reflects the least

efficient pr oduct evaluated.

DOE analyzed efficiency levels (ELs) that spanned the range of energy consumption observed from all available data, as described further in Chapter 7 of this TSD. The lowest efficiency that it observed, which DOE called EL 0, was 267 perce nt of the CEC

- equivalent

en ergy consumption as defined in s ection 5.7.1 . The highest efficiency level that it considered, which DOE called EL 11, was 32 percent of the CEC

- equivalent energy consumption. The range of ELs that DOE considered in its analysis is presented in Table 5

. 9

. In this table, all other efficiency levels are compared to EL4

– the efficiency level which represents the energy consumption equivalent to the current CEC Standard. More information on the selection of EL4 to compare other levels against can be found in Chapter 2 of this TSD.5-28 Table 5

. 9 Cooled Cabinet Efficiency Levels Efficiency Level Percent of CEC

- Equivalent Energy Consumption EL 0 267 % EL 1 200% EL 2 160% EL 3 130% EL 4 ( CEC

- Equivalent ) 100% EL 5 90% EL 6 80% EL 7 70% EL 8 60% EL 9 50% EL 10 40% EL 11 (Max

- Tech) 32%

EL 11 represents the maximum technology (max

- tech) efficiency level for cooled cabinets. DOE defines a max

- tech level to represent the theoretical maximum possible efficiency if all available design options are incorporated. The max

- tech level may not be the same as the maximum available level, which is the highest efficiency unit currently available on the market. Moreover, it is possible that products at the max

- tech level are not commercially available

, because it may not be e conomically feasible to produce them at the present time

.
DOE determined the max

- tech level for cooled cabinets using energy modeling. The energy model for the maximum technology level was based on use of all design options applicable for cooled cabinets. While this product configuration has not likely been tested as a prototype, all of the individual design options have been incorporated in available products. The design options associated with the max

- tech efficiency level for cooled cabinets are summari zed in Table 5

. 10 below , as are the design options associated with the CEC

- equivalent , medium

efficiency, and maximum

- available units . This max

- tech efficiency level is more efficient (has lower energy use) than that of the maximum available products. The costs of the max

- tech efficiency level design options are also quite high, as they are based on extensive use of high

cost design options such as vac uum insulating panels as well as all applicable lower

- cost design options. Details describing how DOE modeled the cost and efficiency impacts of these design options can be found in s ection 5.6 . Further details about each of the units used to develop the
cost

- ef ficiency curve can be found in a ppendix 5A.5-29 Table 5

. 10 Cooled Cabinet Efficiency Level s and Design Options Efficiency Level Designation CEC

Equivalent Medium

Efficiency Max

- Available Max

- Tech

Percent of CEC

Equivalent Energy Use 100% 75% 48% 32%

Condenser Fan Moto r SPM SPM SPM BLDC

Insulation Thickness 1.75” on top and rear, 1.5” on sides and bottom 1.5” on top, sides, and rear, 2” on bottom 2” on all surfaces 2” thick on all

s urfaces

Vacuum

Insulated

Panels None None None VIPs on half the cabinet’s surface

area Compressor 3.0 EER 3.2 EER 4.9 EER Variable

- speed

Evaporator Coldwall Roll

- bond Roll

- bond with fan Round

- Tube, Flat Fin, Forced

convection

Glass Door Baseline (dual

- pane, no low

- e coating

or inert gas filling) Baseline (dual

pane, no low

- e coating or inert gas filling) Medium

- tech (dual

- pane, low

- e

coating, argon

filled) Max

- tech (triple

pane, low

- e coated, krypton

- filled)

5.7.4 Cooled Cabinet Results

DOE developed cost

- efficiency curve s for both 6 ft 3 and 2 ft 3 cooled cabinets. These cost

efficiency curves are presented in the following sections.

5.7.4.1 Six Cubic Foot Cooled Cabinets

T o devel op a cost

- efficiency curve for cooled cabinets , DOE selected three of its reverse

engineered vapor

- compression units of capacity equal to 6 ft 3 and determined the costs of the groups of design options associated with the efficiency improvements of each uni t. The efficiency levels analyzed for the 6 ft 3 cooled cabinet analysis represent the CEC

- equivalent efficiency level , medium efficiency, and max

- available efficiency levels, as shown in Table 5

. 11 The first three levels represent tested and reverse

- engineered cooled cabinets. The fourth level represent s the max

- tech efficiency level described in s ection 5.7.3

. The incremental MSPs are5-30 equal to the markup factor, 1.26 for vapor

- compression cooled cabinets (see section 5.4.7), multiplied by the MPC.

Table 5

. 11 6 ft 3 Cooled Cabinet Efficiency Level s Efficiency Level Description Energy Consumption

(kWh/year) % of CEC Equivalent Energy Consumption Incremental MPC Incremental MSP

CEC

- Equivalent 298 100% $0 $0 Medium

Efficiency 229 75% $25 $31

Max

- Available 137 48% $65 $82

Max

- Tech* 93 32% $204 $258 * Note: This does not represent an actual unit.

DOE calculated its cost

- efficiency curve for 6 ft 3 cooled cabinets using these four points. For intermediate efficiency levels between those represented by these four points, DOE interpolate d the associated incremental costs . For example, the incremental MSP for EL 7 at 7 0% is equal to the incremental cost for the medium efficiency level ( i.e.
, $ 31 ) plus 5 /2 7 times the MPC increase between the medium and max

- available level s, i.e.
, $31 + (5/27)*($82

- $31) = $41. DOE believes that the selected intermediate efficiency levels should be achievable design s based on partial application of the design opt ions ( e.g. , increased insulation thickness)

. DOE did not include ELs 0 through 3 in this cost

- efficiency curve because it is not aware of any 6 ft 3 cooled cabinets at those efficiency levels. Hence, the incremental costs associated with these ELs less than EL4 are all zero. The cost

- efficiency curve for 6 ft 3 cooled

- cabinets is summarized in Table 5

. 12 below.

Table 5

. 12 Incremental Manufacturer Selling Price (MSP) for 6 ft 3 Cooled Cabinets Efficiency Level ( P ercent of CEC

- Equivalent E nergy Consumption ) Incremental MSP EL 0 (267%) $0 EL 1 (200%) $0 EL 2 (160%) $0 EL 3 (130%) $0 EL 4 (10 0%

-- CEC

- Equivalent ) $ 0 EL 5 (9 0% ) $1 5 EL 6 (8 0% ) $2 6 EL 7 (7 0% ) $ 41 EL 8 (6 0% ) $5 9 EL 9 ( 50% ) $7 8 EL 10 (4 0% ) $1 70 EL 11 (32%

-- Max

- Tech) $25 85-31 5.7.4.2 Two Cubic Foot Cooled Cabinets
DOE developed analysis for 2 ft 3 cooled cabinet s to represent lower

- capacity cooled cabinet s

. Product s of this size are available using vapor

- compression, thermoelectric, and absorption refrigeration technologies. Hence, DOE’s analysis for this capacity considered efficiency levels representing greater energy use than the CEC

- equivalent efficiency level . The least

- cost/highest energy use considered for this analysis, called “baseline thermoelectric”, represents 267 percent of the CEC

- equivalent efficiency level

The first point on the 2 ft 3 cost

- efficiency curve represents the tested energy use of a

reverse

- engineered 2 ft 3 thermoelectric unit. The second point on this curve represents a reverse

engineered 2 ft 3 vapor

- compression unit. The incremental cost associated with this second unit include the costs of increasing insulation thickness and conver ting the thermoelectric refrigeration system to a vapor

- compression refrigeration system, as described in section 5.6.8

. Finally, t he efficiency levels of the medi um

- efficiency, max

- available, and max

- tech points correspond to the equivalent levels in the 6 ft 3 curve, although the incremental costs associated with these efficiency levels a re lower due to the unit’s smaller size

. For design options affected by the ca binet size, DOE calculated the costs required to implement such design options for a smaller unit.

DOE used its manufacturing cost model to calculate the cost of increased insulation thickness and a supplemental spreadsheet model to calculate the cost of vacuum

- insulated panels for smaller units. DOE also adjusted its glass door costs to account for the smaller door area of a 2 ft 3 unit. The remaining design options are related to the refrigeration system, which is sized depending on the capacity of the co mpressor. As discussed in Chapter 3 of this TSD, compressor efficiency drops off significantly as capacity decreases. Because 6 ft 3 cooled cabinets already use the smallest

- capacity compressors available on the market today at high EERs, 2 ft 3 units would use the same compressors and thus heat exchanger and fan size would not be reduced

. Consequently, the incremental costs for improved compressors, evaporators, and condenser fan motors for the 2 ft 3 analysis are equal to the equivalent incremental costs of the 6 ft 3 analysis. The efficiency levels of 2 ft 3 cooled cabinet analysi s are presented in Table 5

. 13

. The incremental MSPs are equal to the markup factor, 1.22 for thermoelectric cooled cabinets (see section 5.4.7), multiplied by the MPC.5-32 Table 5

. 13 2 ft 3 Cooled Cabinets Efficiency Levels Efficiency Level Description Energy Consumption

(kWh/year) % of CEC

Equivalent

Energy Consumption Incremental MPC Incremental MSP

Baseline Thermoelectric 663 267% $0 $0

Low

- Efficiency Vapor Compression 167 87% $58 $71

Medium

Efficiency 145 75% $82 $100

Max

- Available 92 48% $115 $140 Max

- Tech 61 32% $225 $275

DOE calculated its cost

- efficiency curve for 2 ft 3 cooled cabinets using the five efficiency levels presented in Table 5.13 , using an interpolation approach, as discussed above for the 6 ft 3 cooled cabinets

. The incremental MSP costs for 2 ft 3 cooled

- cabinets are presented in Table 5.14 below.

Table 5

. 14 Incremental Manufacturer Selling Price (MSP) for 2 ft 3 Cooled Cabinets Efficiency Level ( P ercent of CEC

- Equivalent E nergy Consumption ) Incremental MSP

EL 0 ( 267 %) $0 EL 1 (200%) $26 EL 2 (160% $42 EL 3 (130%) $54 EL 4 (10 0%

-- CEC Equivalent ) $6 6 EL 5 (90%) $ 70 EL 6 (80%) $88 EL 7 (70%) $107 EL 8 (60%) $122 EL 9 (50%) $137 EL 10 (40%) $207 EL 11 (32%

-- Max

- Tech) $2755-33 5.8 NON

- COMPRESSOR REFRIGERA TOR ANALYSIS AND RES ULTS

DOE used a combined efficiency level/design option/reverse engineering approach to develop cost

- efficiency curves for non

- compressor refrigerators. DOE established efficiency lev els defined as percent of baseline energy consumption. DOE’s analysis is based on the efficiency improvements associated with groups of design options. Also, DOE used manufacturing cost models based on reverse engineering of products to calculat e the incre mental costs associated with efficiency improvement s. The following sections describe the details and results of this analysis.

5.8.1 Energy Test Results
DOE tested seven thermoelectric refrigerators representing five models , testing two units each of two of these models. DOE reverse

- engineered two of the models. These thermoelectric refrigerators ranged in capacity from 0.25 ft 3 to 1.7 ft 3 . DOE also tested and reverse

- engineered one 1.2 ft 3 absorption refrigerator. Not one of the tested units achieve d the 39 °F standardized temperature for fresh food compartments when tested in the 90 °F ambient temperature required by DOE’s proposed test procedure for non

- compressor refrigerators (see the 2014 MREF TP NOPR)

. DOE calculated the annual energy consumption of the products using the proposed test procedure, which would require rat ing based on their coldest temperature setting

. The results of these energy tests are presented in Table 5

. 15

.
Table 5

. 15 Non

- Compressor Refrigerator Energy Test Results

Unit Volume (ft 3 ) Compartment Temperature Measured for Cold Setting (°F) Measured Energy Use 1 (kWh/year) TE 2 1, Unit 1 1.7 55.4 578 TE 1, Unit 2 1.7 58.2 559 TE 2, Unit 1 1.7 42.8 622 TE 2, Unit 2 1.7 48.2 596 TE 3 1.6 48.6 832 TE 4 0.87 57.5 565 TE 5 0.25 61.1 451 ABS 2 1 1.2 52.6 569
1 Measured for operation in the cold temperature setting, consistent with the proposed test procedure (see 2014 MREF TP NOPR)

. 2 “TE” refers to thermoelectric refrigerators, while “ABS” refers to absorption refrigerators.5-34 5.8.2 Efficiency Levels

5.8.2.1 Efficiency Levels Corresponding to Reverse

- Engineered Units

Because there are no current federal, state, or voluntary industry energy conservation standards for non

- compressor refrigerators , and because they have no established test procedure, there is no established baseline efficiency level for these products. Therefore, DOE developed its analysis based on th e energy test results in Table 5.15 , selecting both a baseline and a max

available unit to feature in its cost

- efficiency curve.

DOE reverse

- engineered two products of 1.7 ft 3 storage volume , which DOE found to be most representative of the size of non

- compressor refrigerators on the market. Because DOE tested two models of each of these units, DOE selected for its analysis the energy test results associated with the coldest storage temperature achieved by each unit. DOE divided the energy use of the reverse

- engineered unit with the highe st energy consumption by its standard adjustment factor (discussed in Chapter 2 of this TSD) to determine the baseline efficiency level for its non

- compressor refrigerator analysis

. In order to determine efficiency le vel of any given unit, DOE multiplied th e baseline efficiency level by the standard adjustment factor for the unit
to determine the adjusted baseline energy use. The energy consumption

, coldest storage temperature , and efficiency of these two units are sho wn in Table 5

. 16

.
Table 5

. 16 Baseline and Max

- Available Non

- Compressor Refrigerator Efficiency Levels

Unit Volume (ft 3 ) Compartment Temperature Measured for Cold Setting (°F) Standard Adjustment Factor

(90

– T Test_Cold )/

(90

- 39) Measured Energy Use (kWh/year) Adjusted Baseline Energy

Use Percent of Baseline Energy Use

Baseline 1.7 55.4 0.68 578 578 100% Max

Available 1.7 42.8 0.93 622 791 79% The baseline efficiency level corresponding to 39  ̊F compartment temperature is calculated as the energy use of the baseline unit divided by the standard adjustment factor calculated for this unit, i.e.
, 578 ÷ 0.68 = 850. The adjus ted baseline energy use for a cold

- setting compartment temperature is equal to the baseline efficiency level multiplied by the standard adjustment factor.

5.8.2.2 Efficiency Levels Corresponding to Hypothetical Units

T he design of the max

- available unit differ s from that of the baseline unit in two ways

— it has thicker insulation and uses heat pipe to facilitate heat transfer from the hot side of the thermoelectric module to the ambient air . DOE developed a cost

- efficiency curve that also considered levels of ins ulation thickness different than those of the tested units. DOE used ERA5-35 to calculate the thermal load associated with each configuration considered in the analysis

. DOE also used energy modeling to determine a maximum

- technology efficiency level for non

compressor refrigerators using vacuum

- insulated panels on half of the unit’s surface area. Table 5

. 17 summarizes the efficiency levels that DOE analyzed, indicatin g which design options correspond to the different efficiency level s

. DOE analyzed incremental ELs that spanned the range of energy consumption observed from all available data, as presented in Table 5

. 17 . The lowest efficiency that it observed, which DOE called EL 0, was 100 percent of the baseline unit’s energy consumption. DOE calculated costs for efficiency levels in 5 percent increments by interpolating between th e efficiency levels of the analyzed designs. DOE believes that the intermediate ELs are possible through partial adoption of the design options.

Table 5

. 17 Non

- Compressor Refrigerator Efficiency Levels and Des ign Options

Baseline Unit Baseline with Max

- Available Insulation * Max

- Available Unit Max

Available with Added Insulation * Max

- Tech Efficiency

Level * Efficiency Level 100% 82% 79% 67% 64%

Insulation Thickness 1.25” on all sides , 1” on door 1.5” on all sides , 2.5” on door 1.5” on all sides , 2.5” on door 2” on all sides , 2.5”

on door 2” on all sides

, 2.5” on door
Heat Pipe None None Present Present Present Vacuum

Insulated

Panels None None None None VIPs on half the cabinet’s surface area * Note: These do not represent actual models.

5.8.3 Non

- Compressor Refrigerator Results

The incremental MSPs for non

- compressor refrigerators are presented in Table 5

. 18 below.5-36 Table 5

. 18 Incremental MSP for Non

- Compressor Refrigerators Efficiency Level (percent of baseline energy use) Total Added MSP EL 0 (100 %

– Baseline) $0 EL 1 (95 %) $0.27 EL 2 (9 0%) $0.53 EL 3 (85 %) $0.80 EL 4 (8 0%) $10.45 EL 5 ( 7 5%) $16.93 EL 6 (7 0%) $17.33 EL 7 (65%) $27.38 EL 8 ( 64 %

– Max

- Tech ) $35.59

5.9 ICE MAKER ANALYSIS A ND RESULTS
DOE conducted engineering analy sis for ice makers using an efficiency

- level approach

, which calculates the relative costs of achieving increases in energy efficiency levels without regard to the particular design options used to achieve such increases . The following sections describe this anal ysis.

5.9.1 Energy Test Results

DOE tested and reverse engineered two ice makers in each of its three proposed product classes : portable ice makers ( IM

- P), cooled

- storage ice makers ( IM

- C), and uncooled

- storage ice makers ( IM

- U)

. These six units were tested usin g the ice maker test procedure proposed in the 2014 MREF TP NOPR . This test measures the energy use associated with icemaking to serve a daily ice usage of 4 pounds per day and also with maintaining a full bin of ice , both in a 72  ̊F ambient temperature co ndition . For cooled

- storage ice makers, the “ice storage energy” is the energy required to maintain the ice bin temperature below freezing. For uncooled

- storage ice makers, ice storage energy is the energy required to replace ice that melt s . The results of these tests are presented in Table 5.19

.
Table 5

. 19 Ice Maker Test Results Product

Class Harvest Rate (lb/day) Icemaking Energy (kWh/yr) Ice Storage Energy (kWh/yr) Annual Energy Consumption (kWh/yr) IM

- P 27 125 131 256 IM

- P 33 54 35 89 IM

- C 10 417 135 552 IM

- C 14 312 99 411 IM

- U 42 201 875 1,075 IM

- U 25 224 448 6725-37 5.9.2 Efficiency Levels

Because there are no current F ederal, S tate, or industry energy conservation standards for ice makers, and because the proposed DOE test procedure is not consistent with an y established test procedure, there is no established baseline efficiency level for these products. Therefore, DOE developed its analysis based on the above energy test results , selecting both baseline and maximum

- efficiency units for each class based on the data

. DOE analyzed incremental ELs that spanned the range of energy consumption observed from all available data , as presented above in Table 5

. 19 . The lowest efficiency that it observed in each product class, which DOE called EL 0, was 100 percent of the baseline unit’s energy consumption. DOE considered intermediate ELs in 5 percent i ncrements (10

- percent increments for portable ice makers , which spanned a greater range of efficiency ) down to the energy consumption of the maximum

- efficiency unit in each product class. Although these incremental ELs do not represent energy use observed in the tests described above, DOE believes that these ELs are possible through partial adoption of the design differences between the baseline and maximum

- efficiency units in each product class.

DOE did not estimate costs for a maximum

- technology level tha t exceeded the maximum

- efficiency unit tested for any of its proposed ice maker product classes

. DOE observed that there would not be sufficient space to increas e the size of the heat exchangers of the

max imum

- efficiency tested units

. Also , the components ( e.g. , fans and compressors) used in the maximum

- efficiency units were generally the highest efficiency available to the manufacturers for use in ice makers ( e.g. , the maximum

- efficiency IM

- U unit uses a brushless DC condenser fan). Finally, DOE concluded that accurate prediction through the use of theoretical energy modeling of improved efficiency using other design options would be difficult

.
The range of ELs that DOE considered in its ice maker analysis is presented in Table 5

. 20

, Table 5

. 21 , and Table 5

. 22

.
Table 5

. 20 Portable Ice Maker Efficie ncy Levels Efficiency Level Energy Consumption (kWh/year) Percent of Baseline Energy Consumption EL 0 (Baseline) 256 100% EL 1 230 90% EL 2 205 80% EL 3 179 70% EL 4 154 60% EL 5 128 50% EL 6 102 40% EL 7 (Max

- Available ) 89 35%5-38 Table 5

. 21 Cooled

- Storage Ice Maker Efficiency Levels Efficiency Level Energy Consumption (kWh/year) Percent of Baseline Energy Consumption EL 0 (Baseline) 552 100% EL 1 524 95% EL 2 497 90% EL 3 469 85% EL 4 442 80% EL 5 414 75% EL 6 (Max

- Available) 411 74%

Table 5

. 22 Uncooled

- Storage Ice Maker Efficiency Levels Efficiency Level Energy Consumption (kWh/year) Percent of Baseline Energy Consumption EL 0 (Baseline) 1,075 100% EL 1 1,021 95% EL 2 968 90% EL 3 914 85% EL 4 860 80% EL 5 806 75% EL 6 753 70% EL 7 699 65% EL 8 (Max

- Available) 672 63%5-39 5.9.3 Ice Maker Results

DOE developed cost

- efficiency relationships for all three proposed product classes of ice makers based on the measured test results and the calculated cost difference s between the least

efficient (baseline) and most

- efficient (max

- available ) models that it tested in each class. The calculated cost differences focused on design details that DOE considered to influence energy use, for example, refrigeration system cost and cabinet construction. In general, DOE developed the costs for most of these design options using the same meth odology outlined in s ection 5.2

. Using the incremental cost for the maximum efficiency design, DOE calculated costs for the selected intermediate efficiency levels using interpolation. The incremental MSPs for the three ice maker product classes are presen ted in Table 5.23 through Table 5

. 25

.
Table 5

. 23 Incremental Manufacturer Selling Price Results for Portable Ice Makers Efficiency Level (percent of baseline energy use) Total Added MSP EL 0 (100%

-- Baseline) $0 EL 1 (90%) $1.30 EL 2 (80%) $2.59 EL 3 (70%) $3.89 EL 4 (60%) $5.18 EL 5 (50%) $6.48 EL 6 (40%) $7.78 EL 7 (35%

-- Max

- Available) $8.43

Table 5

. 24 Incremental Manufacturer Selling Price Results for Cooled

- Storage Ice Makers Efficiency Level (percent of baseline energy use) Total Added MSP EL 0 (100%

-- Baseline) $0 EL 1 (95%) $3 EL 2 (90%) $6 EL 3 (85%) $9 EL 4 (80%) $12 EL 5 (75%) $14 EL 6 (74%

-- Max

- Available) $165-40 Table 5

. 25 Incremental MSP Results for Uncooled

- Storage Ice Makers Efficiency Level (percent of baseline energy use) Total Added MSP EL 0 (100%

-- Baseline) $0 EL 1 (95%) $3 EL 2 (90%) $7 EL 3 (85%) $10 EL 4 (80%) $14 EL 5 (75%) $17 EL 6 (70%) $21 EL 7 (65%) $23 EL 8 (63%) $26

5.10 HYBRID REFRIGERATION PRODUCTS ANALYSIS AN D RESULTS
Hybrid refrigeration products are similar in design, construction, and operation to

consumer refrigeration products that are already covered and are subject to Federal energy conservation standards ( i.e. , refrigerators, refrigerator

- freezers, and freezers) and use identical components

- the key difference being the inclusion of one or more compart ment s operated at warmer temperatures that comprise at least half of a hybrid product’s refrigerated volume

. Because hybrid refrigeration products and conventional refrigerators, refrigerator

- freezers, and freezers are functionally and physically similar, DOE considered whether it would be appropriate
to apply the 2014 energy conservation standards for conventional refrigeration products to hybrid products , using adjustments to account for the different average compartment temperatures of hybrid products

.

T o this end, DOE conducted analysis to evaluate hybrid product energy use and whether this energy use would be compliant with an appropriate application of the 2014 energy conservation standards. The results of this analysis , presented in this section, indi cate that this standard can be applied to hybrid products if they use design options that are available and commonly used in refrigeration products

.

5.10.1 Comparison of Hybrid and Conventional Refrigeration Products
Hybrid refrigeration products are constructed using the same types of technologies as conventional refrigerator

- freezers ( e.g. , polyurethane foamed insulation cabinet construction,
vapor

- compression refrigeration systems, and the same compressor , heat exchanger, and fan options). The key differences are that (1) at least one of the compartments in a hybrid refrigeration product, representing at least half the refrigerated volume, is a cellar compartment, not designed to achieve storage temperatures lower than 39  ̊F; (2) the hybrid refrigeration produc t doors that provide access to the cellar compartment(s) are often transparent, constructed using glass layers; and (3) the usage profile of a hybrid refrigeration product is expected to more closely resemble the usage profile of a cooled cabinet ( wine chi ller ) rather than that of a5-41 refrig erator or refrigerator

- freezer. These differences are reflected in the proposed test procedure for hybrid refrigeration products, which would specify a cellar compartment st andardized temperature of 55 °F and would appl y a usage adjustment factor of 0.85 to calculate energy consumption. These differences would affect the measured energy consumption of hybrid refrigeration products, as compared to conventional refrigerator

- freezers, in the following ways:

1) Thermal load associ ated with the 50 percent or greater portion of the refrigerated volume that is not capable of maintaining compartment temperatures lower than 39  ̊F would be lower than the thermal load of a fresh food or freezer compartment . Specifically, the temperature d ifference with respect to ambient for this portion of the volume would be 35  ̊F (90  ̊F minus 55  ̊F) rather than 51  ̊F (90  ̊F minus 39  ̊F) for a fresh food compartment or 90  ̊F (90  ̊F minus 0  ̊F) for a freezer compartment

. 2) Thermal load associated with the t ransparent doors would be greater than the thermal load associated with a solid door. For doors that enclose cellar compartments, the additional load of the transparent doors would be balance d by the reduced load of the warmer compartment temperatures. For transparent doors covering the entire product, including fresh food compartments, an approach used in some hybrid refrigerator products, clearly the thermal load for a transparent fresh food door would be greater than the load of an identical compartment with a solid door.

3) The 0.85 usage adjustment factor would reduce the measured energy use.

The proposed test procedure for hybrid refrigeration products also proposes applying a volume adjustment factor of 0.69 to the measured storage volume of cellar compa rtments. Consequently, a hybrid refrigeration product would have a lower maximum allowable energy consumption compared to that of a refrigerator , refrigerator

- freezer, or freezer of the same refrigerated volume

. Ultimately this volume adjustment factor and the combined effects of the factors listed above would lead to a level of stringency when considering compliance with a given standard that may be greater or less than for a conventional refrigeration product

. DOE expects that the refrigeration system eff iciency of a hybrid product would be equivalent to that of a corresponding conventional refrigeration product. The evaporating temperatures and condensing temperatures would be similar. In order to transfer the refrigeration capacity to the cabinet, the evaporating temperature would be somewhat lower than the coolest compartment temperature, which would be identical fo r comparable hybrid and conventional refrigeration products. For example, for a hybrid refrigeration product having only fresh food and cellar compartments, the coolest compartment temperature during the test would be near 39  ̊F (generally just above or be low this temperature, depending on the control setting) . Similarly, the coolest compartment temperature for an all

- refrigerator without a freezer compartment would be near 39  ̊F. The condensing temperatures would be somewhat higher than the test

- prescribed 90  ̊F ambient temperature for both types of products. Because the evaporating and condensing temperatures of comparable hybrid and conventional refrigeration products’ refrigeration systems would be similar, and because the same compressors are available for and can be used in5-42 all of these products, the refrigeration system coefficient of performance (COP) would be equivalent for these products. This is in contrast to cooled cabinets, for which the coolest compartment temperature during testing would be ne ar 55  ̊F, and for which the refrigeration system COP could therefore be very different than for conventional refrigerators, whose standardized compartment temperature is 39  ̊F ( e.g. , for the fresh food compartments of refrigerators).

5.10.2 Analysis Approach

In o rder to evaluate the suitability of the 2014 energy conservation standard levels for hybrid refrigeration products, DOE conducted an analysis to quantify the impacts of the three key potential differences in measured energy use for hybrid refrigeration pro ducts discussed above , as well as the impact of the volume adjustment factor . DOE compared the thermal load of various configurations of hybrid refrigeration product s to the thermal loa d of a comparable all

refrigerator and evaluated whether the stringency of the 2014 energy standards would be increased or decreased for hybrid refrigeration products as compared with an all

- refrigerator.

DOE conducted this analysis using the energy modeling tools described in s ection 5.5

, including the ERA energy model and the WINDOW model for calculating the thermal resistance of the glass doors. DOE evaluate d th re e hybrid designs with characteristics as follows :
1) One single glass door covering both the cellar compartment and the fresh food compartment 2) Dual glass doors, one for each compartment 3) Dual doors: glass for the cellar compartment and solid for the fresh food compartment

For compact hybrid products, DOE considered all three sce nario s , although the first and second scenarios are most common in compact hybrid products. For standard

- sized hybrid products, DOE only considered the second and third scenarios, although the third scenario is most common in standard

- sized hybrid products

. DOE did not consider the first scenario (single glass door) for standard

- sized products because no such products currently exist on the market. To examine the sensitivity of the load to different design details, DOE modeled the products with two differen t insulation thicknesses (1.5 and 2 inches) and three different glass door designs. The glass door designs are consistent with those used for the cooled cabinet engineering analysis described in s ection 5.6 : a baseline glass door having two uncoated panes with air insulation, a medium

- tech door having two glass layers, each with low

- e coating

, and argon insulation, and a

max

- tech door design having three glass layers, each with low

- e coating

, and krypton insulation. DOE also modeled hybrid products wi th both 50

- percent and 75

- percent cellar volume to examine the effects of the volume adjustment factor. DOE performed this analysis for a 6 cubic foot product wh ich, as an all

- refrigerator, would be of class 1 3A ( compact all

- refrigerators with automatic de frost) and a 12 cubic foot product corresponding to class 3A (all

- refrigerators with automatic defrost)

. Table 5.26 summarizes the product configurations analyzed, and Table 5.275-43 summarizes the design options and combinations of design options considered t o improve efficiency.

Table 5

. 26 Hybrid Product Configuration

Size Cellar Volume (%) Doors Fresh Food Cellar

Compact: 6 ft 3 50% Solid Glass
Glass Glass Single Glass Door Covering Both Compartment s

75% Solid Glass Glass Glass Single Glass Door Covering Both Compartments

Standard: 12 ft 3 50% Solid Glass
Glass Glass

75% Solid Glass Glass Glass

Table 5

. 27 Design Options Analyzed for Hybrid Products Descriptions of Individual Design Options Insulation • Baseline: 1.5

- inch Thickness

• 2

- inch Thickness Transparent Doors • Baseline: Two uncoated glass layers, air fill

• Two low

- emissivity glass layers, argon fill

• Three low

- emissivity glass layers, krypton fill Compressor Efficiency (compact products) System COP/EER * • Baseline: 0.82 / 2.8 Btu/h

- W

• 0.94 / 3.2 Btu/h

- W Compressor Efficiency (standard

- size products) System COP/EER * • Baseline: 1.58 / 4.8 Btu/h

- W

• 1.91 / 5.8 Btu/h

- W

Descriptions of Design Option Combinations Tech 1 Baseline + 2

- inch Insulation Tech 2 Baseline + 2

- inch Insulation + Mid Tech Glass Tech 3 Baseline + 2

- inch Insulation + Mid Tech Glass + Higher Efficiency Compressor Tech 4 Baseline + 2

- inch Insulation + Max Tech Glass Tech 5 Baseline + 2" Insulation + Max Tech Glass + Higher Efficiency Compressor *System performance is the net capacity (evaporator capacity minus evaporator fan heat) divided by system power input during the compressor on

- cycle, including power input of the compressor, fans, and control components.5-44 The candidate system efficiencies can be reasonably achieved by available compressors and fan motors. For example, for standard

- size systems, an Embraco EMY60HER compressor has a nominal capacity of 610 Btu/hr and EER of 5.04 at traditional compressor rating conditions of

- 10  ̊F evaporating temperature and 130  ̊F condensing temperature

— this level of performance is far from the peak levels achieved by modern compressors. When operating with an evaporating temperatur e of 14  ̊F and a condensing temperature of 113  ̊F in a system cooling a refrigerator, using fans that draw 6 W each and a control system that draws 6 W, the system EER is 7.0 Btu/h

- W.

For the selected product configurations, DOE first calculated the range of expected thermal load s for the hybrid product and for the conventional refrigerator

. DOE then proceeded to compare the energy use of otherwise comparable refrigerators and hybrid refrigeration products. The energy use of a conventional refrigerator with one fresh food compartment would be as shown in Equation 1 , where L ff is the thermal load of the single large fresh food compartment , and COP is the unit’s coefficien t of performance:

Equation 1

E RRR = L
CCC

DOE assumed that this refrigerator is minimally compliant with the 2014 standards

— hence E Ref is identically equal to the standard for a product of the specified volume of the gi ven product class. The value of COP need for compliance with the standards can be determined based on the calculated values for E Ref and L ff . DOE only considered values of L ff for which the calculated COP can be achieved by available refrigeration systems

. The energy use of a hybrid refrigeration product would be as shown in Equation 2 , where L

h is the thermal load of the hybrid cabinet

. As mentioned above, DOE considered several hybrid configurations, so L h has a range of values. The value of COP determined for the all

- re frigerator is used to convert the term to an expression containing calculated loads and the refrigerator
energy use.
Equation 2

E HHHHHH = 0

. 85 × L h CCC = 0

. 85 × E RRR × L h L

DOE conducted this analysis for hybrid product configurations as described in Table 5

. 26 above, using design option combinations as described in Table 5

. 27 . For each product/design option combination, DOE determined the energy use and by what percentage the energy use is above or below the standard level, calculated based on product adjusted volume using the 0.69 volume adjustme nt factor for the cellar compartment

.5-45 5.10.3 Results

The results of the hybrid product analyses are presented in Table 5.28 as percentages representing by what amount the energy use of the analyzed configurations are above or below the calculated standard levels. For example, a

- 19 percent indicates that the product’s energy use is 19 percent below the calculated standard level. The analysis shows that all of the analyzed product configurations can be designed to be compliant with one of the considered grou ps of design options. Furthermore, the analysis shows that none of the product configurations require use of maximum

- technology glass doors to achieve compliance, other than the standard

- size product with 50

- percent cellar volume and separate glass doors o n both the cellar and fresh food compartments. However, as discussed above, this is not considered to be a common product configuration, and the use of a solid door on the fresh food compartment would avoid required use of maximum

- technology glass doors. T his analysis shows that the suggested approach for application of the 2014 refrigeration product standards to hybrids is achievable for hybrid refrigerators using design options that are in currently common use

.5-46 Table 5

. 28 Hybrid Refrigeration Product Design Changes

Size Cellar Percentage Volume DoorsBaselineTech 1Tech 2Tech 3Tech 4Tech 5 Cellar Fresh FoodCompact 50% Solid Solid

- 8%

- 19%

- - - -

Glass Solid 16% 4%

- 7%

- 20%

- 12%

- 24%

Glass Glass 54% 44% 12%

- 3%

- 1%

- 15%

Single Solid Door

- 17%

- 29%

- - - - Single Glass Door 45% 25% 3%

- 11%

- 10%

- 23%

75% Solid Solid

- 11%

- 22%

- - - -

Glass Solid 26% 15%

- 3%

- 17%

- 11%

- 24%

Glass Glass 45% 35% 7%

- 8%

- 5%

- 19%

Single Solid Door 21%

- 32%

- - - - Single Glass Door 36% 26%

- 3%

- 16%

- 15%

- 27%Standard 50% Solid Solid

- 5%

- 19%

- - - -

Glass Solid 27% 14%

- 2%

- 19%

- 9%

- 25%

Glass Glass 76% 37% 23% 2% 6%

- 12%

75% Solid Solid

- 10%

- 22%

- - - -

Glass Solid 41% 7% 4%

- 14%

- 7%

- 23%

Glass Glass 66% 55% 17%

- 3% 0%

- 17%5-47 REFERENCES

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