`
`Evaluation of Retrofit
`Variable-Speed Furnace
`Fan Motors
`R. Aldrich and J. Williamson
`Consortium for Advanced Residential Buildings
`
`January 2014
`
`Nidec Motor Corporation
`IPR2014-01121
`
`Exhibit 2021 - 1
`
`

`

`
`
`NOTICE
`
`This report was prepared as an account of work sponsored by an agency of the United States government.
`Neither the United States government nor any agency thereof, nor any of their employees, subcontractors, or
`affiliated partners makes any warranty, express or implied, or assumes any legal liability or responsibility for the
`accuracy, completeness, or usefulness of any information, apparatus, product, or process disclosed, or
`represents that its use would not infringe privately owned rights. Reference herein to any specific commercial
`product, process, or service by trade name, trademark, manufacturer, or otherwise does not necessarily
`constitute or imply its endorsement, recommendation, or favoring by the United States government or any agency
`thereof. The views and opinions of authors expressed herein do not necessarily state or reflect those of the
`United States government or any agency thereof.
`
`Available electronically at http://www.osti.gov/bridge
`
`Available for a processing fee to U.S. Department of Energy
`and its contractors, in paper, from:
`U.S. Department of Energy
`Office of Scientific and Technical Information
`P.O. Box 62
`Oak Ridge, TN 37831-0062
`phone: 865.576.8401
`fax: 865.576.5728
`email: mailto:reports@adonis.osti.gov
`
`Available for sale to the public, in paper, from:
`U.S. Department of Commerce
`National Technical Information Service
`5285 Port Royal Road
`Springfield, VA 22161
`phone: 800.553.6847
`fax: 703.605.6900
`email: orders@ntis.fedworld.gov
`online ordering: http://www.ntis.gov/ordering.htm
`
`Printed on paper containing at least 50% wastepaper, including 20% postconsumer waste
`
`
`
`Nidec Motor Corporation
`IPR2014-01121
`
`Exhibit 2021 - 2
`
`

`

`
`
`
`
`
`
`Technical Report:
`Evaluation of Retrofit Variable-Speed Furnace Fan Motors
`
`Prepared for:
`
`The National Renewable Energy Laboratory
`
`On behalf of the U.S. Department of Energy’s Building America Program
`
`Office of Energy Efficiency and Renewable Energy
`
`15013 Denver West Parkway
`
`Golden, CO 80401
`
`NREL Contract No. DE-AC36-08GO28308
`
`Prepared by:
`
`Robb Aldrich and Jim Williamson
`
`Steven Winter Associates, Inc.
`
`of the
`
`Consortium for Advanced Residential Buildings (CARB)
`
`61 Washington Street
`
`Norwalk, CT 06854
`
`
`
`NREL Technical Monitor: Cheryn Metzger
`
`Prepared under Subcontract No. KNDJ-0-40342-03
`
`
`
`January 2014
`
`iii
`
`Nidec Motor Corporation
`IPR2014-01121
`
`Exhibit 2021 - 3
`
`

`

`
`
`
`
`[This page left blank]
`
`iv
`
`Nidec Motor Corporation
`IPR2014-01121
`
`Exhibit 2021 - 4
`
`

`

`
`
`Contents
`List of Figures ............................................................................................................................................ vi
`List of Tables .............................................................................................................................................. vi
`Definitions .................................................................................................................................................. vii
`Acknowledgments ................................................................................................................................... viii
`Executive Summary ................................................................................................................................... ix
`1
`Introduction and Background ............................................................................................................. 1
`1.1 Concept 3 Motor Controls and Airflow ...............................................................................1
`1.2 Installation............................................................................................................................2
`2 Research/Experimental Methods ........................................................................................................ 4
`2.1 Research Questions ..............................................................................................................4
`2.2 Technical Approach .............................................................................................................4
`2.3 Measurements ......................................................................................................................5
`2.4 Monitoring Equipment .........................................................................................................6
`2.5 Analysis................................................................................................................................6
`2.6 Identifying Sites ...................................................................................................................7
`3 Results ................................................................................................................................................... 9
`3.1 Motor Replacement ..............................................................................................................9
`3.2 Initial Test Results .............................................................................................................10
`3.3 Long-Term Monitoring Results .........................................................................................14
`3.3.1 Heating ...................................................................................................................14
`3.3.2 Cooling ...................................................................................................................17
`3.4 Fan-Only Operation ...........................................................................................................19
`3.5 Homeowner Feedback .......................................................................................................20
`3.6 Site No. 1: Customer Satisfaction Challenges ...................................................................20
`3.7 Site No. 4: Flow Rate Challenges and Evergreen IM Motor .............................................21
`4 Discussion ........................................................................................................................................... 23
`4.1 Duct Leakage and Static Pressure ......................................................................................23
`4.2 Concept 3 Versus Evergreen IM ........................................................................................25
`4.3 Achieving Proper Flow Rates ............................................................................................25
`4.4 Noise 26
`4.5 Older Equipment ................................................................................................................26
`4.6 System Compatibility.........................................................................................................27
`4.7 Cost Effectiveness ..............................................................................................................27
`5 Conclusions ........................................................................................................................................ 28
`References ................................................................................................................................................. 30
`Appendix A: Air Handling Unit Electricity Versus Heat Delivered ....................................................... 31
`Appendix B: Air Handling Unit Electricity Versus Sensible Cooling ................................................... 33
`Appendix C: Furnace Runtime Versus Average Outdoor Air Temperature ........................................ 36
`Appendix D: Installation Questionnaire .................................................................................................. 40
`
`
`v
`
`Nidec Motor Corporation
`IPR2014-01121
`
`Exhibit 2021 - 5
`
`

`

`
`
`List of Figures
`Figure 1. Wiring diagram from the Concept 3 Installation Manual ........................................................ 2
`Figure 2. BPM motor with retrofit belly band being replaced in a Rheem furnace at site no. 3 ......... 9
`Figure 3. (Left): Original PSC motor at site no. 7 with mounting brackets; (Right): Concept 3 motor
`installed with retrofit belly band kit. ................................................................................................. 10
`Figure 4. Flow/power during heating operation ..................................................................................... 13
`Figure 5. Flow/power during cooling operation ..................................................................................... 13
`Figure 6. Flow/power during fan only operation .................................................................................... 14
`Figure 7. Relationship of furnace electricity (with different motors) to heat delivered at site 2 ...... 15
`Figure 8. Heating runtime regression for site no. 4 ............................................................................... 16
`Figure 9. Poor correlation between fan energy and outdoor air temperature at site 5 ..................... 17
`Figure 10. Relationship of air handler electricity (with different motors) to sensible cooling at site
`2. ........................................................................................................................................................... 19
`Figure 11. Angle bracket installed on the return trunk to prevent the duct from “popping” in and
`out on fan startup and shutdown ...................................................................................................... 21
`Figure 12. Power reduction in cooling mode versus differential static pressure .............................. 24
`
`Unless otherwise noted, all figures were created by CARB.
`
`List of Tables
`Table 1. Summary of Equipment Used for Testing and Monitoring....................................................... 6
`Table 2. Summary of Installer Feedback. ............................................................................................... 11
`Table 3. Flow and Power Measurements of Furnaces During Heating Operation ............................. 12
`Table 4. Flow and Power Measurements of Air Handlers During Cooling Operation ........................ 12
`Table 5. Flow and Power Measurements of Air Handlers During Fan Only Operation ...................... 12
`Table 6. Estimated Annual Furnace Runtime and BPM Motor Savings During Heating Operation . 16
`Table 7. Estimated Additional Gas Costs. .............................................................................................. 17
`Table 8. Estimates of Annual Cooling Run Time and Fan Energy Savings. ....................................... 18
`Table 9. Estimated Savings (Both Heating and Cooling) at Each Site from BPM Motor. .................. 18
`Table 10. Estimated Savings (Fan-Only) at Each Site From BPM Motor ............................................. 19
`Table 11. Power and Flow Measurements at Site 4 ............................................................................... 22
`Table 12. Pressure, Leakage, and Power Savings During Cooling Operation ................................... 24
`
`Unless otherwise noted, all tables were created by CARB.
`
`vi
`
`Nidec Motor Corporation
`IPR2014-01121
`
`Exhibit 2021 - 6
`
`

`

`
`
`Definitions
`AHU
`
`BPM
`
`CARB
`
`CFM
`
`ECM
`
`HVAC
`
`NREL
`
`Air handling unit
`
`Brushless, permanent magnet (motor)
`
`Consortium for Advanced Residential Buildings
`
`Cubic feet per minute
`
`Electronically commutated motor
`
`Heating, ventilation, and air conditioning
`
`National Renewable Energy Laboratory
`
`NYSERDA
`
`New York State Energy Research and Development Authority
`
`PEG
`
`PSC
`
`SIR
`
`Proctor Engineering Group
`
`Permanent split capacitor (motor)
`
`Savings-to-investment ratio
`
`TrueFlow
`
`Device used to measure AHU’s airflow rate
`
`
`
`
`
`vii
`
`Nidec Motor Corporation
`IPR2014-01121
`
`Exhibit 2021 - 7
`
`

`

`
`
`Acknowledgments
`This project was co-funded by the New York State Research and Development Authority
`(NYSERDA) and the U.S. Department of Energy Building America Program. The Consortium
`for Advanced Residential Buildings (CARB) would also like to thank Proctor Engineering Group
`(PEG), the developer of the Concept 3 motor, Tag Mechanical, and all of the homeowners
`
`participating in the evaluation.
`
`viii
`
`Nidec Motor Corporation
`IPR2014-01121
`
`Exhibit 2021 - 8
`
`

`

`
`
`Executive Summary
`In conjunction with NYSERDA and PEG, CARB has evaluated the Concept 3 replacement
`motors for residential furnaces. These brushless, permanent magnet (BPM) motors can use much
`less electricity than their PSC (permanent split capacitor) predecessors. These motors have been
`primarily developed for and used in cooling-dominated climates. This evaluation focuses on the
`heating-dominated climate of upstate New York. Previous studies have been based largely on
`modeling, laboratory testing, and/or benefits of BPM motors in new furnaces. This study
`specifically focuses on replacement BPM motors in cold-climate homes to characterize field
`performance and cost effectiveness. The results of this study are intended to be useful to home
`performance contractors, heating, ventilation, and air conditioning (HVAC) contractors, and
`home efficiency program stakeholders.
`
`The project includes eight homes in and near Syracuse, New York. During initial site visits,
`baseline tests were performed (pressures, flows, and power consumption) and monitoring
`equipment was installed. The monitoring equipment ran for approximately 6 months, recording
`portions of both heating and cooling seasons. After this stage, CARB returned to the home with a
`technician from Tag Mechanical (the HVAC contractor), replaced the motor, repeated the tests,
`and reset the monitoring equipment for another 6 months.
`
`Not surprisingly, results indicate that BPM replacement motors will be most cost effective in
`homes with right-sized HVAC equipment (with longer run times) and proper ductwork (i.e., low
`static pressures). Additionally, more dramatic savings can be realized if the occupants use fan-
`only operation to circulate air when there is no thermal load. There are millions of cold-climate,
`U.S. homes that meet these criteria, but the savings in most homes tested in this study were
`modest.
`
`There were certainly substantial electric power reductions with the new motors. Average fan
`power reductions were approximately 126 Watts during heating and 220 Watts during cooling
`operation. Over the course of entire heating and cooling seasons, these translate into modest
`average electric energy savings of 163 kWh. Average cost savings were $20/year. Homes where
`the fan was used outside of heating and cooling modes saved an additional $42/year on average.
`
`In the homes tested, heating and cooling savings alone would not usually justify the installed cost
`of approximately $475. Installed costs would need to be less than $300 to achieve a savings-to-
`investment ratio of at least 1.0. However, in the homes where the air handler fan was used in
`“fan-only” mode (in addition to heating and cooling), average savings-to-investment ratio was
`1.3 with an internal rate of return of 7.5% at an installed cost of $475. This replacement motor
`measure, therefore, should be used selectively in homes where several of the following
`conditions apply:
`
`• The furnace likely has at least 10 years of useful life remaining.
`• Heating and cooling equipment is right-sized (thus operates longer and more frequently).
`• Operating pressures are relatively low (no constrictive ducts).
`• The furnace fan is frequently used outside of heating and cooling operation.
`
`ix
`
`Nidec Motor Corporation
`IPR2014-01121
`
`Exhibit 2021 - 9
`
`

`

`
`
`Introduction and Background
`1
`Most existing residential furnaces use permanent split capacitor (PSC) motors. A few of these
`motors have multiple speeds (sometimes accomplished by using multiple sets of coils), but most
`PSC motors vary speed by changing the slip which has a small effect on the power draw. Higher
`efficiency motors have been available for a number of years and have been used as replacements
`for refrigeration evaporator fan motors. Since 1985, furnace manufacturers have used higher
`efficiency, variable-speed BPM fan motors (also known as electronically commutated motors or
`ECMs) in some high-end residential furnaces. In recent years, new furnaces with BPM motors
`have gained market share. Instead of single- or multi-speed PSC motors, most new two-stage
`furnaces employ BPM motors to achieve a wider performance range with lower power
`consumption. The vast majority of existing residential furnaces, however, employ relatively
`inefficient PSC motors.
`
`The benefits of BPM blower motors have been well documented in studies such as the Energy
`Center of Wisconsin 2003 study of field performance of new residential furnaces, which found
`50% electric energy savings in heating, 31% savings in cooling, and 80% savings for continuous
`fan operation (Pigg 2003). Other studies have shown the savings depend dramatically on heating,
`ventilation, and air conditioning (HVAC) system characteristics, especially static pressure
`differentials (Lutz et al. 2006; Walker 2007).
`
`Until recently, BPM motors were quite expensive. Incremental costs for BPM motors in a new
`furnace were typically $800–$1,200. While this incremental cost has come down for new
`furnaces, BPM motors have been impractical to retrofit into existing furnaces due to
`incompatible control requirements. In 2008, the Concept 3 BPM motor became commercially
`available (the motor is now sold as the Fieldpiece LER motor). The Concept 3 is designed
`specifically for retrofit into existing furnaces as a replacement for the standard PSC motors. Cost
`to the installing HVAC contractor is less than $200, which is competitive with PSC replacement
`motors. This reduced cost could make installation of these motors more practical and cost
`effective. The goal of this project was to evaluate exactly this: the practicality and cost
`effectiveness of the Concept 3 drop-in replacement ECM motors in cold climates.
`
`1.1 Concept 3 Motor Controls and Airflow
`The Concept 3 motor is designed to interface with a typical 24-Volt thermostat that allows for
`heating, cooling, and fan-only operation. The configuration and controls of the Concept 3 are
`simple. This streamlines installation, but it may also limit the savings functionality of the system.
`For cooling operation, there are two possible configurations:
`
`• Dry climate. The fan motor runs at 100% speed during a call for cooling. After the
`thermostat is satisfied, the motor runs for an additional 4–10 minutes at 25% speed to
`take advantage of the cold coil.
`• Humid climate. The fan motor runs at 85% of full speed during a call for cooling. The
`fan shuts off immediately at the end of the call to prevent drying the coil. If fan-only
`operation is called for, the fan will not operate for 20 minutes after a cooling cycle. If
`another cooling call occurs within this period, the system will turn on.
`
`1
`
`Nidec Motor Corporation
`IPR2014-01121
`
`Exhibit 2021 - 10
`
`

`

`
`
`The cooling mode is determined by the connection of a single wire on the Concept 3 motor (see
`Figure 1). Regardless of the cooling setting, during a call for heating the fan motor runs at 85%
`of full speed beginning 30 seconds after the call begins. After the call ends, the fan runs for an
`additional 3 minutes. During a call for fan-only, the motor will run at approximately 50% of full
`speed.
`
`In New York State, the humid setting was obviously chosen for cooling operation. There are two
`potential limitations associated with this:
`
`• Motor speed is limited to 85%. Matching existing flow rates can be challenging.
`• Motor speed is the same for both heating and cooling operation; airflow rates are
`therefore nearly identical.
`
`Installation
`1.2
`While the control configuration (discussed above) can be limiting, wiring and configuring the
`motor are very straightforward. Figure 1 shows the wiring diagram from the Concept 3
`installation manual. The connection that can differ is the orange wire—used to determine humid
`or dry cooling modes.
`
`
`Figure 1. Wiring diagram from the Concept 3 Installation Manual (PEG 2010)
`
`
`The physical installation of the motor is straightforward as well—provided that the motor being
`replaced also uses a belly band. Rheem and Ruud furnaces typically use bracket mounts to secure
`
`2
`
`Nidec Motor Corporation
`IPR2014-01121
`
`Exhibit 2021 - 11
`
`

`

`
`
`the motors in the fans. At the two sites where original motors used bracket mounts, the motor
`replacement required twice as much time. At other sites, switching the motor took an average of
`
`2 hours.
`
`3
`
`Nidec Motor Corporation
`IPR2014-01121
`
`Exhibit 2021 - 12
`
`

`

`
`
`2 Research/Experimental Methods
`2.1 Research Questions
`The key questions that this research and evaluation project set out to answer are:
`
`• What are the electric power and energy implications (during both cooling and heating) of
`the new BPM motor in these test homes when compared to the original PSC motor?
`• How do the savings vary with different system characteristics, including flow rate, static
`pressure difference, and duct leakage?
`• How difficult is it to install the replacement motor? What are typical installed costs?
`In what systems are these motors most practical and cost effective?
`•
`• What simple tests can be performed on systems to accurately assess potential benefits of
`the replacement motors and identify cost-effective candidates for the retrofit?
`
`As the project progressed, it was clear that one additional question is very important:
`
`• How many furnaces are compatible with the Concept 3 motor? Can furnaces be upgraded
`on a wide scale?
`
`2.2 Technical Approach
`CARB worked with Tag Mechanical, an HVAC contractor in Syracuse, New York, to identify
`10 residential forced-air systems that meet these general requirements:
`
`•
`
`• Homes must be in New York State—a requirement associated with the NYSERDA
`cofunding.
`In order to evaluate savings under all operating conditions, homes must have central,
`forced-air heating and cooling systems.
`• To streamline monitoring systems, each AHU must not serve multiple zones (i.e., no
`zone dampers—homes that achieve zoning with multiple AHUs may still be good
`candidates).
`• To be compatible with the Concept 3 motor, AHUs must use ½-hp (or smaller) PSC
`motors.
`• Some furnaces have brackets mounted to their motors and are poor candidates. Any
`furnace with a motor mount other than a belly band poses some challenges.
`• Units must use 24-Volt thermostats.
`• The existing motor should rotate clockwise (viewed from the shaft end).
`• The furnace cabinet width must be 17 in. or greater.
`• Owners must agree to participate in the study and sign the participation agreement.
`Owners receive an efficient fan motor installed at no cost to them.
`
`4
`
`Nidec Motor Corporation
`IPR2014-01121
`
`Exhibit 2021 - 13
`
`

`

`
`
`After a customer signed the agreement and after verifying that the furnace appears to be
`compatible with the Concept 3 motor, CARB and Tag scheduled a preliminary visit to the home.
`After verifying that the system was compatible with the Concept 3 motor, the following tests
`were performed:
`
`• Combustion safety tests to ensure systems are operating safely
`• Recording of make, model, and configuration of all system components
`• Duct leakage tests
`• Under steady-state conditions, measurement of power, voltage, current, power factor,
`supply plenum static pressure, and return plenum static pressure at each operating
`condition (heating, cooling, and fan-only)
`• Replacing the furnace filter with a TrueFlow pitot array plate and repeating the above
`measurements along with velocity pressure and airflow rate at each operating condition
`Installation of monitoring equipment (described below)
`•
`• Verification that the system was operating properly before leaving.
`
`Long-term monitoring covered part of a cooling season and part of a heating season. After
`approximately 6 months, each site was revisited and the motor was replaced. Each of the
`measurements listed above was repeated with the new motor in place.
`
`CARB worked closely with installers of each new motor to determine how much time the
`replacement process took, how much this installation would cost, if there were any unforeseen
`challenges with this particular system, etc.
`
`2.3 Measurements
`The first step in evaluations was safety testing. CARB checked for gas leaks and performed
`combustion safety tests at all homes. Duct leakage measurement was generally the next step in
`the process. The overall procedure for duct blaster tests was as follows:
`
`1. Turn HVAC systems off.
`2. Using tape or other material, block or mask all supply and return registers.
`3. Remove filter.
`4. Attach the blower to the duct system—typically at the AHU.
`5. Insert a static pressure reference tap, typically in the supply plenum.
`6. Turn on the duct blaster fan and pressurize the duct system to 25 Pa.
`7. Measure the flow rate through the fan; this is the total duct leakage.
`
`Power measurements were taken with a Fluke 43B power quality analyzer with an i30s current
`probe. During short-term tests, CARB recorded one-time measurements of voltage, current,
`power, and power factor of the furnace under each operating condition (heating, cooling, and fan
`only). During heating, these measurements were taken after the burner had ignited and the igniter
`
`5
`
`Nidec Motor Corporation
`IPR2014-01121
`
`Exhibit 2021 - 14
`
`

`

`
`
`had turned off. During cooling, similar electrical measurements were taken on the condensing
`unit.
`
`Long-term monitoring was accomplished using Onset Computer Hobo data loggers. Loggers
`recorded data at 2-minute intervals for 30 days during the cooling season and 60 days during the
`heating season. Monitored parameters were:
`
`• Outdoor temperature and relative humidity
`• Supply plenum air temperature
`• Return plenum air temperature and relative humidity
`• Current draw of the AHU
`• Current draw of the condensing unit (during cooling).
`
`2.4 Monitoring Equipment
`The key equipment used in the project is outlined in Table 1.
`
`Table 1. Summary of Equipment Used for Testing and Monitoring
`Measurement
`Equipment Needed
`Carbon Monoxide Concentrations and
`Bacharach Fyrite Pro
`Draft Pressure
`Energy Conservatory Series B Duct Blaster
`Duct Leakage
`Pressure Measurements (Other Than
`Energy Conservatory DG 700 manometer
`Combustion Draft Pressures)
`Energy Conservatory TrueFlow Pitot array
`Airflow Rate
`plate
`Fluke 43B power quality analyzer with i30s
`current sensor
`Onset Hobo U12-011
`Onset Hobo U12-006 with TMC20-HD
`Onset Hobo U23-001
`Onset Hobo U12-006 with CTV-A current
`transducer
`
`Electrical Power, Current, and Voltage
`Return Plenum Air Temperature and
`Relative Humidity
`Supply Plenum Air Temperature
`Outdoor Air Temperature
`AHU and Condensing Unit Current
`
`
`2.5 Analysis
`As the short-term test methodology describes, CARB measured the power consumption and flow
`characteristics of each motor under steady state at each operating condition. The somewhat
`simplified long-term monitoring protocol (utilizing current sensors) was primarily meant to
`document runtime of the system during each operating mode.
`
`When analyzing heating performance, it was determined that the furnace was in heating mode
`when the furnace current was above a threshold (approximately 3 Amps) and when there was a
`large temperature rise (usually 10°–20°F) across the furnace. These thresholds varied a small
`amount from system to system. This runtime, in conjunction with the steady-state power
`
`6
`
`Nidec Motor Corporation
`IPR2014-01121
`
`Exhibit 2021 - 15
`
`

`

`
`
`measurements, provided estimates for electrical energy consumed for space heating. A very
`similar approach was used for cooling (with current and temperature drop thresholds).
`
`Ideally, real electrical energy consumed by each system over each monitoring period would have
`been measured. The primary reason that such a strategy was not pursued was the added time,
`equipment, and intrusiveness to set up such monitoring equipment. Initial site visits typically
`required 4–5 hours. Installing more rigorous electrical monitoring equipment would have
`required more time—possibly the installation of an additional electrical box and requiring
`services of an electrician. While project budgets would have been stretched too thinly with this
`approach, the added time required—from the homeowners’ perspective—was the key limitation.
`Finding participants to the study was by far the largest hurdle encountered, and longer, more
`intrusive, and more frequent site visits would not have been acceptable to many participants.
`
`Approximate thermal energy delivered to the home was calculated based on flow rates measured
`during short-term tests and measured temperature differentials. As with electrical energy
`consumption, less uncertainty would be achieved with more rigorous monitoring. For example,
`heat calculations assume flow is constant as measured during short-term tests. Flow rates will
`vary based on filter status, wet coils, etc. In addition, supply temperature values are from single-
`point measurements. As with more rigorous electrical monitoring, installing flow arrays and
`averaging temperature sensors would have increased the installation time and would not have
`been acceptable to many participants. These uncertainties are relatively modest, and conclusions
`would not be different with more rigorous measurement protocols.
`
`Knowing system runtime in each mode, indoor air conditions, outdoor air conditions, and supply
`air temperatures allow for apples-to-apples comparisons of system performance with the two
`types of motors. Using local climate data (NREL 2005) in conjunction with the outdoor
`temperature and humidity conditions recorded at the sites, results from the relatively short
`monitoring period (1–2 months for each season for each motor) were extrapolated to annual
`energy consumption.
`
`Identifying Sites
`2.6
`One unexpected finding was the limited number of systems that were compatible with the
`Concept 3 motor. Syracuse, New York is obviously in a heating-dominated climate. As such,
`there are many homes that do not have central air conditioning (this was a requirement of
`NYSERDA for the evaluation—that both heating and cooling performance be monitored). It is
`estimated that 60%–80% of people contacted or considered for this study were not considered
`further because they did not have forced-air systems that provide both heating and air
`conditioning.
`
`Among sites that did have central furnaces and air conditioning, many people were simply not
`interested in participating in the study. Researchers reached out to hundreds of contacts in the
`Syracuse area, but interested responses were rare. It is very hard to quantify this aspect of sample
`selection, as non-responses can mean many different things.
`
`Finally, among homeowners contacted who both had air conditioning and were interested in
`participating in the study, a majority of systems were not compatible with the Concept 3 motor.
`The key reasons for this:
`
`7
`
`Nidec Motor Corporation
`IPR2014-01121
`
`Exhibit 2021 - 16
`
`

`

`
`
`• Many furnaces encountered had ¾-hp motors. The Concept 3 can replace only ½-hp
`and smaller motors. At least 50% of interested candidates with air conditioning were
`ruled out because of large furnace motors.
`• Rheem and Ruud furnaces. The vast majority of furnace motors have belly bands.
`Rheem and Ruud furnaces, on the other hand, have motors that use bracket mounts.
`While retrofitting a Rheem/Ruud furnace with a belly band is possible, PEG recommends
`against it (as does a Tag Mechanical technician after replacing one such motor in the
`study).
`• Small cabinets. In order for the new motors to be installed with proper clearance, furnace
`cabinets must be at least 17 in. wide. Approximately five systems that did have smaller
`motors (1/5 to 1/2 hp) were encountered, but with narrow cabinets (~14 in.).
`Because of these challenges, project participation goals (10 sites) were not fully met. CARB
`ultimately found 12 sites, but two were disqualified because of combustion safety concerns and
`two occupants mo