# Presentation: 233791

## Central Air Conditioner Test Procedure Public Workshop:

***Central Air Conditioner Test Procedure Public Workshop:***

***A Technical Discussion On New Defaults for***

## Slide 2

## Key Issue:

***Key Issue:***
***Balance the two main effects from lowering the Cooling***

***Mode Cyclic Degradation Coefficient, ***

**Reduced testing burden**
**Higher SEER ratings for some models**

## NIST’s Goal:

***NIST’s Goal:***

## OUTLINE

**Background***** ***
**Data**
**Influential Hardware Features**
**Possible Sets of Default       Values**
**Manufacturer’s Rating Decisions and ARI Certification Requirement**

**Predicted Reduction in Test Burden**

**Impact on Raising SEER Ratings**

## OUTLINE

**Background**
**What is       ?**
**How does       affect SEER?**
**How burdensome is the testing?**
**Data**
**Influential Hardware Features**
**Possible Sets of Default       Values**
**Manufacturer’s Rating Decisions and ARI Certification Requirement**
**Predicted Reduction in Test Burden**
**Impact on Raising SEER Ratings**

## What is       ? 

**Used in quantifying part load performance**
**        ****is the **_**[slope](slide78.xml)**__** (linear fit) of the PLF (=                      )            versus CLF curve***_
**Used to calculate SEER,**
**For single-speed systems, use a **_**[short-cut calculation](slide80.xml)**__**:**_
**For two-capacity and variable-speed systems, use a “bin” calculation: **
***         ***

***An exponential fit was considered but not adopted in the 1988 revision.**

## Cooling Load Factor (-)

**Cooling Load Factor (-)**

**Part Load Factor (EER****cyc ****/ EER****ss****)**

**Press for an Additional Plot**

##      = 0.25 versus:  0.20      0.15      0.10      0.05      0.00

***         *****has a bigger effect on single-speed units versus two-capacity and variable-speed units**
**SEER Gain for single-speed systems**
***     *****= 0.25 versus:  **_**0.20**_**      **_**0.15**_**      **_**0.10**_**      **_**0.05**_**      **_**0.00**_
**SEER Improvement    2.9%      5.7%       8.6%      11.4%     14.3%**
**SEER Gain for modulating systems depends on the degree of unloading (****Below example: 47% unloading at 82****°F****)**
*** ******	******	*****= 0.25 versus:  **_**0.20**_**      **_**0.15**_**      **_**0.10**_**      **_**0.05**_**      **_**0.00**_
**SEER Improvement    0.9%      1.9%       2.7%      3.6%       4.4%**

## How Burdensome is the Testing?

***       *****determined from two dry coil tests**
- One Steady-State Test (the C Test)
- One Cyclic Test (the D Test)
**“****. . . takes approximately 40% of all laboratory testing time” (York written comments)**
**C & D testing “simply confirms what is already known and wastes valuable time” (Carrier oral statement)**
**Extra test time:  6 to 12 hours**
- Extra set-up and tear down
- Time to dry indoor room
- C Test longer if using outdoor air enthalpy as check
- Depends on the number of cycles run for the D Test

## How Burdensome is the Testing?

**ARI Certification:  Process and Costs **
**ITS sets up for cyclic testing (DOE damper boxes)**
**The wet-coil A and B tests are conducted**
**Check:  Is SEER w/ default > 0.95 ******** Certified SEER**
**Manufacturer may elect for ITS not to do C& D tests if the unit passes using the        default**
**Manufacturer saves $750 if C & D Tests are not conducted**

## OUTLINE

**Background**
**Data**
**Data Sources Used by NIST**
**Is the Sample Biased?**
**Influential Hardware Features**
**Possible Sets of Default       Values**
**Manufacturer’s Rating Decisions and ARI Certification Requirement**
**Predicted Reduction in Test Burden**
**Impact on Raising SEER Ratings**

## Hardware Features That May Affect 

**Type of expansion device**
**With or without indoor fan OFF delay**
**Air conditioner versus heat pump**
**With or without a liquid line solenoid valve**
**Size/capacity of unit**
**Type of compressor (scroll versus reciprocating)**
**Internal volume of indoor/outdoor coils**
**Parasitic power**
**With or without an accumulator**
**Quantity of refrigerant charge**
**Type of refrigerant**

**Not Included in final data set**

**Included in final data set**

## Factors Included in ARI-Provided Data Set

**Lab measured (at ITS)**
**Rated cooling capacity**
**Unit Type**
**Packaged (blower coil)**
**Split blower coil**
**Split coil only**
**Rated SEER**
**Indoor fan delay (Y/N)**
**Liquid line solenoid (Y/N)**
**Type of expansion Device**
**Fixed orifice**
**TXV bleed**
**TXV non-bleed**
**AC or HP**
**Compressor Speed (1 or 2)**
**Niche products**

**Off Cycle Equalization (Y/N)**

**Affected Final Data Set used by NIST**

## Data Sources Used by NIST

**ARI Certification Data from Year 2000**
**Basis for evaluating alternative      defaults**
**CEC Appliance Certification Database**
**Used in evaluating the distribution of               **
**Used in evaluating the distribution of SEER decimal**
**Large sample:  6787       entries; 7218 for SEER decimal**
**ARI Primenet Database**
**Used in evaluating the distribution of SEER decimal**
**Very large sample: 55935 system manufacturer ratings**
**	****	****	****	****       ****25736 independent coil manuf. ratings**

## Data Sources Used by NIST

**ARI Certification Data from Year 2000**
**All data from ITS lab testing**
**ARI-provided data set = 339 units**
**Data set used by NIST = 322 units (exclude two-capacity and niche products)**
**648 units tested as part of Year 2000 certification program**
**Assume the total sample of 648 units is representative of the overall population.**
**Question: Are the 322 units representative of the overall population?**

## Data Set Used by NIST:  322 of 339 Units

**Data Set Used by NIST:  322 of 339 Units**

**Measured**** **

## Normalized Histogram:  ARI & CEC       Data

**Frequency of Occurrence (%)**

**  ****Value**

**=> Difference Suggests Possibility that one Data Set is Slightly Biased**

## OUTLINE

**Background**
**Data**
**Influential Hardware Features**
**Industry Recommendations**
**NIST Analysis**
**Possible Sets of Default       Values**
**Manufacturer’s Rating Decisions and ARI Certification Requirement**
**Predicted Reduction in Test Burden**
**Impact on Raising SEER Ratings**

## Industry Recommendations

**Written comments from ARI and Trane**
**Both support 3 categories:  A, B, and C**
**A:  equalizing without indoor fan delay**
**B:  non-equalizing without indoor fan delay and**
**	**
**C:  non-equalizing with indoor fan delay**
**Both acknowledge significant data scatter**
**“****OEMs have data showing scrolls provide ********0.015 lower       than recips” (Copeland)**

**equalizing with indoor fan delay**

**(****Standard deviations from 0.036 to 0.055)**

## NIST Analysis

## Exploratory Data Analysis:

***Screen to Find Primary Factors***

**Graphical data analysis**
- Scatter Plots (Is a factor important?)
- Mean Plots (Is a factor important?)
- Box Plots (Is a factor important?)
- DEX Median/Mean Plots (Most important factors?)
- Multi and Subset Plotting (Interactions?)
- Block Plot (Is a factor “robustly” important?)
**Classical data analysis**
**Regression (Capacity)**
**ANOVA (one-way and two-way)**
**t-test**

## Design of Experiment (DEX) Mean Plot

**Nominal**
**Capacity**

**Design of Experiment (DEX) Mean Plot**

**TDR**
**(N / Y)**

**Exp Valve**

**AC / HP**

**Split / Packaged**

**Coil-Only / Blower Coil**

**0**

**0.05**

**0.10**

**0.15**

## Box Plots

**Box Plots**

**Measured**

**Measured**

**Nominal Capacity**

**Type of Expansion Valve**

**W/O TDR**

**W/ TDR**

**FO**

**TXV-B**

**TXV-NB**

**AC**

**HP**

**SPLIT**

**SINGLE PACKAGE**

**COIL-ONLY**

**BLOWER COIL**

**1.5     2    2.5   3    3.5   4    4.5   5**

## Design of Experiment (DEX) Mean Plot

**Design of Experiment (DEX) Mean Plot**

**0**

**0.05**

**0.10**

**0.15**

**Nominal**
**Capacity**

**TDR**
**(N / Y)**

**Exp Valve**

**AC / HP**

**EQUAL /**
**NONEQUAL**

**ARI**

**ARl**
**MODIFIED**

**EQUIP**
**TYPE**

## Box Plots

**Box Plots**

**Measured**

**Measured**

**Nominal Capacity**

**Type of Expansion Valve**

**W/O TDR**

**W/ TDR**

**FO**

**TXV-B**

**TXV-NB**

**1.5  2 2.5  3  3.5  4  4.5 5**

**AC**

**HP**

**EQUAL**

**NON-EQUAL**

**ARI Equipment Category**

**A**

**C**

**B**

**ARI-Modified**

**A**

**C**

**B1**

**B2**

**Equipment Category**

**Type of Equipment**

**SP-CO**

**SP-BC**

**PACK**

## Primary Factors

**Leading candidates**
**Industry recommended equipment categories (A,B, C)**
**Provides option for more resolution**
**Category B1: non-equalizing without indoor fan delay **
**Category B2: equalizing with indoor fan delay**
**Relatively generic:  allows multiple options for qualifying as “equalizing” versus “non-equalizing”**
**Rated capacity**
**Further comparison of the leading candidates deferred until the next section **

## OUTLINE

**Background**
**Data**
**Influential Hardware Features**
**Possible Sets of Default       Values**
**Industry Recommendations**
**Based on Percentiles **
**Manufacturer’s Rating Decisions and ARI Certification Requirement**
**Predicted Reduction in Test Burden**
**Impact on Raising SEER Ratings**

## Industry Recommendations

## ARI’s Recommended       Defaults

**Rationale **
**“****The current default was set over two decades ago and the technology has advanced so drastically that the default value is now virtually useless.”**
**Scatter in the data is expected given the manufacturing and test tolerances. **
**“****The overall net effect on ratings is close to zero, as would be expected using the mean values.”**
**“****. . . with the mean values it is possible to eliminate as much as 50% of the DOE testing.”**
**“****The time and the money saved with fewer tests will help industry bring new products to the market at a faster rate.”**
**	**

***ARI’s Recommended       Defaults***

## Trane’s Recommended        Defaults

**Considered AC and HP separately**
**“****For simplification, we would favor a single set . . .”, the higher of the AC or HP        default for each equipment category (A, B, and C)**

***Trane’s Recommended        Defaults***

## Trane’s Recommended        Defaults

**Data “variability is extremely high . . .;” using the  means “would significantly degrade consumer confidence in the SEER ratings.”**
**“****. . . the confidence will be 90% that tested values will be less than or equal to the defaults.”****  **
**“****If lower        defaults are adopted, we feel they should not apply to equipment with continually energized compressor sump heaters.”**

***Trane’s Recommended        Defaults***

## Industry Recommended        Defaults

| Equipment
Category | Equalize During Off Cycle | Indoor Fan Off Delay | Proposed        Defaults* |  |
| --- | --- | --- | --- | --- |
|  |  |  | ARI | Trane |
| A | Yes | No | 0.10 | 0.18 |
| B | No | No | 0.075 | 0.14 |
|  | Yes | Yes |  |  |
| C | No | Yes | 0.055 | 0.11 |

***Proposed        defaults based on the same data set:  334 units tested in 2000 at ITS as part of the ARI Certification program.**

## Consideration of Different       Default Levels

**Chose percentiles over (upper) tolerance intervals**
**Avoid concerns over departure from a normal distribution**
**Data more choppy but most accurately reflects the data**
**9 Percentiles Levels Considered:  50% to 99%**
**More insight on equipment categories**
**Ideally want rank ordering of equipment categories not to change if considering one percentile level versus another (stratified data versus spaghetti data)**

## Percentile Trends:  Industry Recommended Equipment Categories

**Percentile Trends:  Industry Recommended Equipment Categories**

**Percentile**

## Percentile Trends:  Industry-Modified Primary Factors

**Percentile Trends:  Industry-Modified Primary Factors**

**Percentile**

## Percentile Trends: Rated Cooling Capacity

**Percentile Trends: Rated Cooling Capacity**

**Percentile**

**1.5 Ton**

**2.0 Ton**

**4.5 Ton**

**5.0 Ton**

**4.0 Ton**

**2.5 Ton**

**3.0 Ton**

**3.5 Ton**

## Equipment Category

- _[Equipment Category](slide83.xml)_

## Equipment Category

- _[Equipment Category](slide83.xml)_

## Pros and Cons:

***Using One, Three, or Four***
***       ******Default Categories***

## Pros and Cons:  Having 1       Default Category

**Pros**
**Simplest Approach**
**Maintains the original/present test procedure practice**
**Easiest to implement at the independent test lab; don’t have to figure out what features a particular unit has**
**Cons**
**Doesn’t provide any means for differentiating between hardware features**
**Greatest benefit to those units that do the poorly on the C and D Tests **

## Pros and Cons:  Having 3       Default Categories

**Pros**
**Provides differentiation between hardware features**
**The “credit” from adding a component that results in non-equalization (e.g., non-bleed TXV) is the same as adding a time delay off relay ******** 2 groups within Category B**
**Would be preferred by stakeholders who seek greater sales of non-bleed TXV units**
**If wanting to achieve Category B status, there is no       difference in the incentive for adding a TDR versus using a non-bleed TXV **

## Pros and Cons:  Having 3       Default Categories

**Cons**
**Fan delay is statistically more important than equalization / non-equalization ******** supports breaking Category B into its 2 subgroups**
**Independent lab has to additional work to verify the units’ default       equipment category**

## Pros and Cons:  Having 4       Default Categories

**Pros**
**Provides even more differentiation between  hardware features**
**Breaking Category B into its two subgroups is statistically justified **

**Cons**
**Gives a slightly greater incentive to add a TDR versus adding a component that results in non-equalization, like a non-bleed TXV**
**Independent lab has to additional work to verify the units’ default       equipment category**

## Where Are We?

***(Inhale . . . Exhale)***

**Considered:  **
**Which equipment features to base the new      defaults**
**Possible numbers for the new        defaults**
**Time To (Momentarily) Change Gears**
**Put the raw        data aside for a moment**
**Try to model rating tendencies of manufacturers and the Pass/Fail criterion of ARI certification testing**

## OUTLINE

**Background**
**Data**
**Influential Hardware Features**
**Possible Sets of Default       Values**
**Manufacturer’s Rating Decisions and ARI Certification Requirement**
**3 rating approaches plus ARI certification**
**Doesn’t depend on the data!**
**Predicted Reduction in Test Burden**
**Impact on Raising SEER Ratings**

## Consider 4 “Rating” Scenarios

**C and D Tests Conducted to Meet DOE Rating Requirements**
**Considered 3 Scenarios (Y1, Y2, and Y3)**
**Summarized on next slide**
**C and D Tests Conducted to Meet ARI Certification Requirements ******** One Scenario (Z)**
**Manufacturer projected not to test if:**

**Note:  Scenario Z is a maximum impact case because some manufacturers will choose to test at ITS even if their unit passes using the default **

## “Rating” Scenarios Y1, Y2, and Y3

**	****	****   ****Manufacturer projected to test only if:**

**Y1.  **

**or**

**Y2.  **

**Y3.**

**even if only by 0.01**

**case; best prediction of how much testing will be reduced**** **

**Middle-of-the-road => believed to be the most representative**

**More liberal => highest predicted impact**

**Most conservative => lowest predicted impact**

## ARI-Provided      Dataset:  324 Entries

**ARI-Provided      Dataset:  324 Entries**
**(Exclude Apparent Lab Measured SEER Values) **

**Decimal Portion of the Rated SEER**

**Frequency of Occurrence (%)**

## CEC Database:  7218 Entries

**CEC Database:  7218 Entries**

**Decimal Portion of the Rated SEER**

**Frequency of Occurrence (%)**

## ARI PrimeNet:  10 System Manufacturers

**ARI PrimeNet:  10 System Manufacturers**
**(55935 AC&HP Entries) **

**Decimal Portion of Rated SEER**

**Frequency of Occurrence (%)**

## ARI PrimeNet:  4 Independent Coil Manufacturers

**ARI PrimeNet:  4 Independent Coil Manufacturers**
**(25736 AC&HP Entries) **

**Decimal Portion of Rated SEER**

**Frequency of Occurrence (%)**

## Projected Test / No-Test Conditions

**Generate SEER Grid:  EER****B**** Versus**
**EER****B**** from 10.0 to 17.0 in 0.1 increments**
**       ****from 0.25 to 0.0 in 0.01 increments**
**For Each Combination of Possible Default    Level and “Rating” Scenario (Y1, Y2, Y3, & Z):**
**Consider each SEER block on grid**
**Assign to each block:  Yes/No Regarding Testing**
**Determine Percentage of “No Test” blocks for each  level and five different EER****B**** ranges**
**10.0 to 17.0**
**10.0 to 15.0 ******** **_[Best Match for Equip. Category B1](http://www.eren.doe.gov/buildings/appliance_standards/residential/docs/Data_Distr_B1.xls)_
**10.0 to 13.0 ******** Best Match for Equip. Category A**
**11.0 to 15.0 ******** Best Match for Equip. Categories B2 & C**
**11.0 to 13.0**

## Links to SEER Grid Examples

***Links to SEER Grid Examples***

**Present Situation:  Default       =0.25**
- _[Scenario Y1](http://www.eren.doe.gov/buildings/appliance_standards/residential/docs/Y1_CD_025.xls)_
- _[Scenario Y2](http://www.eren.doe.gov/buildings/appliance_standards/residential/docs/Y2_CD_025.xls)_
- _[Scenario Z](http://www.eren.doe.gov/buildings/appliance_standards/residential/docs/Z_CD_025.xls)_
**Theoretical Case #1:  Default       =0.15**
- _[Scenario Y1](http://www.eren.doe.gov/buildings/appliance_standards/residential/docs/Y1_CD_015.xls)_
- _[Scenario Y2](http://www.eren.doe.gov/buildings/appliance_standards/residential/docs/Y2_CD_015.xls)_
- _[Scenario Z](http://www.eren.doe.gov/buildings/appliance_standards/residential/docs/Z_CD_015.xls)_
**Theoretical Case #2:  Default       =0.075**
- _[Scenario Y1](http://www.eren.doe.gov/buildings/appliance_standards/residential/docs/Y1_CD_0075.xls)_
- _[Scenario Y2](http://www.eren.doe.gov/buildings/appliance_standards/residential/docs/Y2_CD_0075.xls)_
- _[Scenario Z](http://www.eren.doe.gov/buildings/appliance_standards/residential/docs/Z_CD_0075.xls)_

## End Product:Estimates of the Projected Reduction in C and D Tests Associated with different Default        Levels

**For the 4 “Rating” Scenarios**
**For the 5 EER****B**** Ranges**
**3 Examples:**
**Default       =0.20**
**Default       =0.12**
**Default       =0.05**

## Default       = 0.20

**Percent Reduction in Testing**

**Rating Scenario Y3**

**Rating Scenario Y2**

**Rating Scenario Y1**

**Rating Scenario Z**

## Default      = 0.12

***Default      = 0.12***

**Percent Reduction in Testing**

**Rating Scenario Y3 (******** ******** 0.01)**

**Rating Scenario Y2 (#.00)**

**Rating Scenario Y1 (#.00, #.50)**

**Rating Scenario Z (ARI Cert.)**

## Default       = 0.05

***Default       = 0.05***

**Percent Reduction in Testing**

**Rating Scenario Y3 (******** ******** 0.01)**

**Rating Scenario Y2 (#.00)**

**Rating Scenario Y1 (#.00, #.50)**

**Rating Scenario Z (ARI Cert.)**

## OUTLINE

**Background**
**Data**
**Influential Hardware Features**
**Possible Sets of Default       Values**
**Manufacturer’s Rating Decisions and ARI Certification Requirement**
**Predicted Reduction in Test Burden**
**Now overlay the        data**
**Tabulate all the options**
**Impact on Raising SEER Ratings**

## Now Overlay the CD Distribution Associated With Each Equipment Category

**Distributions for Each Equipment Category (A, B1, B2, and C)**
**Estimated Scatter Plot Used to Select EER****B**** Range (EER****B**** estimated from measured      and rated SEER)**
**Histogram Used to Project Reduction in Testing**
**Projected Testing Reduction for each set of       Defaults and each “Rating” Scenario **
**Percent reduction for each equipment category**
**Percent reduction for all equipment categories**

## Equipment Category C

**Equipment Category C**

**Measured**** **

**Estimated EER****B**

**Selected EER****B**** Interval**** **

## Histogram:  Equipment Category A

**Frequency of Occurrence**

**Histogram:  Equipment Category A**

## Histogram:  Equipment Categories B1 and B2

**Histogram:  Equipment Categories B1 and B2**

**Frequency of Occurrence**

## Histogram:  Equipment Category C

**Histogram:  Equipment Category C**

**Frequency of Occurrence**

## Overlay: “Rating” Scenarios for Default      = 0.20

***Overlay: “Rating” Scenarios for Default      = 0.20***
***With Equipment Category “A” Histogram***

**Percent Reduction in Testing**

**Scenario Y1**

**Scenario Y2**

**Scenario Y3**

**Frequency of Occurrence**

**Scenario Z**** **

**Eq Cat A**

## Slide 66

## Slide 67

## Slide 68

## Slide 69

## Slide 70

## Slide 71

## Slide 72

## Slide 73

## OUTLINE

**Background**
**Data**
**Influential Hardware Features**
**Possible Sets of Default       Values**
**Manufacturer’s Rating Decisions and ARI Certification Requirement**
**Predicted Reduction in Test Burden**
**Impact on Raising SEER Ratings**
**General effect**
**Relative to the NAECA minimums**

## Slides for this section will be added at a later date.

## Suggested Refinements

**Seek information that will help determine whether the       data set is representative of the overall population or biased. **
**Seek information (%) from ARI/ITS on how many units pass using the existing 0.25       default but still have the C and D Tests conducted.**
**Others?**

## Appendix

## Calculating       and Using It To Determine

***Cyclic Efficiency***

**Calculate based on 2 tests **
**Apply to estimate performance at multiple operating conditions**
***         ***

**Press to Return**

## Comparison of Two PLF Curves Corresponding to Two Different Cyclic Degradation Coefficients 

**Cooling Load Factor (-)**

**Part Load Factor (EER****cyc ****/ EER****ss****)**

**Comparison of Two PLF Curves Corresponding to Two Different Cyclic Degradation Coefficients **

**Press to Return**

## Calculating SEER for Single-Speed Systems

**SEER(Short-cut Method) ******** SEER(Bin Method)**
**	**
**Short-cut Method adopted for Single-speed systems**
**Short-cut Method Parameters**
**Only Need EER****B**** and the Part Load Factor (PLF) corresponding to a 50% load factor**
**Use       to get PLF(50%)**

***Calculating SEER for Single-Speed Systems***

## SEER For Single-Speed Systems:

**Cooling Load Factor (-)**

**Part Load Factor (EER****cyc ****/ EER****ss****)**

**SEER For Single-Speed Systems:**
**  ****The Single Point Used From the PLF vs CLF Plot**

## Calculating SEER for Single-Speed Systems

**Press to Return**

**Equation Derivation,**

## Equipment Categories

| Equipment
Category | Equalize During Off Cycle | Indoor Fan Off Delay | Equipment
Examples |
| --- | --- | --- | --- |
| A | Yes | No | Cap Tube
Orifice
Bleed TXV |
| B1 | No | No | Non-Bleed TXV
Electronic Exp Device
Liquid Line Solenoid |
| B2 | Yes | Yes | Cap Tube
Orifice
Bleed TXV |
| C | No | Yes | Non-Bleed TXV
Electronic Exp Device
Liquid Line Solenoid |

**Press to Return**