591 (SI)-2015

AHRI Standards 550/590 (I-P)-2015 & 551/591 (SI)-2015 Updates from 2011 Version with Addendum 3

Agenda                  

Background Purpose Learning Objectives Referenced Documents Section 1, Purpose Section 2, Scope Section 3, Definitions Section 4, Test Requirements Section 5, Rating Requirements Section 6, Minimum Data Requirements for Published Ratings Section 7, Conversions and Calculations Section 8, Symbols and Subscripts Appendix C, Method of Test Appendix D, Derivation of IPLV Appendix E, Chiller Condenser Entering Air Temperature Measurement Appendix F, Atmospheric Pressure Adjustment Appendix G, Water Pressure Drop Measurement Procedure Appendix H, Heating Capacity Test Procedure Accompanying Tools – –

2

Kadj Atmospheric Correction

Background Purpose  Background – In 2015 work was completed on updating the AHRI 550/590 (IP) and AHRI 551/591 (SI) Standards which have been released as AHRI 550/590 (IP)-2015 and AHRI 551/591 (S)-2015 – All sections except Section 4 are effective April 1, 2016 • Section 4 is effective January 1, 2017

– In addition the Operational Manuals for the ACCL and WCCL certification programs have been updated and released as of 4/1/2016

 Purpose – This presentation will focus on the changes to the Standards and a separate presentation will cover the Operational Manual changes – Review changes in the 2015 version of both standards that differ from the 2011 version

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Learning Objectives

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Learning Objectives  Learning Objective Goals – To provide and overview of the changes to the AHRI 550/590 (IP) and AHRI 551/591 (SI) standards relative to the 2011 version with addendum 3 – The intent is to provide a uniform training document that can be used by users of the standard and laboratories around the world – As there have been significant changes to testing requirements and procedures the presentation will also provide further insight into the reasons for the changes and how they are applied – The intent of this presentation is to supplement the Standards but is not intended to replace the standard and all requirements interpretations will be based on the standard documents

5

Reference Documents  Document Location – The following documents are available free of charge at the AHRI website http://www.ahrinet.org/site/686/Standards/HVACR-Industry-Standards/Search-Standards

 Reference Documents – AHRI Standard 550/590 (I-P)–2015 with Errata, Performance Rating of Water-chilling and Heat Pump Water-heating Packages Using the Vapor Compression Cycle – ANSI/AHRI Standard 550/590 (I-P)-2011 with Addendum 3 – AHRI Standard 551/591 (SI)-2015 with Errata, Performance Rating of Water-chilling and Heat Pump Water-heating Packages Using the Vapor Compression Cycle – ANSI/AHRI Standard 551/591 (SI)-2011 with Addendum 3 – Appendix G Pressure Drop Adjustments – Calibration Worksheet

 Other References – Kadj Calculation Spreadsheet Tool – ASHRAE 90.1

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Section 1, Purpose

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Section 1, Purpose  The purpose of this standard is to establish for Water-chilling and Heat Pump Water-heating Packages using the vapor compression cycle with the following areas of focus: – Definitions – Test requirements – Rating requirements – Minimum data requirements for Published Ratings – Marking and nameplate data – Conversions and calculations – Nomenclature – Conformance conditions  The standard is intended for guidance of the industry, including manufacturers, engineers, installers, efficiency regulators, contractors and users.  This standard is subject to review and amendment as technology advances. It is typically updated every 5 years but there may also be addendums

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Section 2, Scope

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Section 2, Scope  This standard applies to air-cooled and water-cooled chillers in both heating and cooling mode  These Water-chilling and Water-heating Packages include: – Water-cooled, Air-cooled, or Evaporatively-cooled Condensers – Water-cooled heat recovery condensers – Air-to-water heat pumps – Water-to-water heat pumps with a capacity greater or equal to 135,000 Btu/h. Water-to-water heat pumps with a capacity less than 135,000 Btu/h are covered by the latest edition of ASHRAE/ANSI/AHRI/ISO Standard 13256  This standard does not cover – Absorption chillers which are covered by AHRI Standard 560 – Chillers with secondary fluids other than water.

10

Section 2, Scope  The scope of the standards includes products and capacity ranges that may not be current covered under the AHRI ACCL and WCCL certification programs  Shown is the current 2016 WCCL scope for the certification program  Refer to the WCCL Presentation for more details

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Section 2, Scope  Shown is the current 2016 ACCL scope for the certification program  Refer to the ACCL Presentation for more details

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Section 3, Definitions

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Overview of Changes  Section 3: Definitions – 3.3 Capacity – Clarification – 3.3.1 Gross Heating Capacity - clarification of heat balance to energy balance – 3.3.2 Gross Refrigerating Capacity - clarification of heat balance to energy balance – 3.4 Compressor Saturated Discharge Temperature – added more detail about what should be included in measurements – 3.5.4 Water-cooled Heat Recovery Condenser – enhanced to add additional information – 3.7.1 Cooling Energy Efficiency • 3.7.1.1 Cooling Coefficient of Performance (COPR) – enhanced for clarity • 3.7.1.2 Energy Efficiency Ratio (EER) - enhanced for clarity • 3.7.1.3 Power Input per Capacity. (kw/tonR) - enhanced for clarity

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Overview of Changes  Section 3: Definitions – 3.7.2 Heating Energy Efficiency • 3.7.2.1 Heating Coefficient of Performance (COPH) - enhanced for clarity – 3.7.3 Simultaneous Cooling and Heating Energy Efficiency (new section) • 3.7.3.1 Heat Recovery Coefficient of Performance (COPHR) - enhanced for clarity • 3.7.3.2 Simultaneous Heating and Cooling Coefficient of Performance (COPSHC) – New definition added for units that are operating in a manner that uses both the net heating and refrigerating capacities generated during operation – 3.8.1 Fouling Factor Allowance – Changed the symbol to Rfoul,sp and enhanced for clarity – 3.10.2 Non-Standard Part-Load Value (NPLV) - enhanced for clarity on application specifics. – 3.11 Percent Load (%Load) - enhanced for clarity to specifically define the use of this term

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Overview of Changes  Section 3: Definitions – – – –

3.14 Significant Figure – new definition for this term 3.16 Total Input Power – revised to clarify intent 3.17 Turn Down Ratio - enhanced for clarity 3.18 Unit Type – (new section) • 3.18.1 Configurable Unit - new definition for this term • 3.18.2 Packaged Unit - new definition for this term – 3. 19 Water-chilling or Water-heating Package • 3. 19.1 Heat Recovery Water-chilling Package - new definition for this term • 3. 19.2 Heat Pump Water-heating Package - new definition for this term • 3. 19.3 Modular Chiller Package - new definition for this term • 3.19.4 Condenserless Chiller - new definition for this term – 3.20 Water Pressure Drop - enhanced for clarity and simplification

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Section 4, Test Requirements

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Impact of Significant Figures & Rounding on Pass-Fail Acceptance

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Significant Figures & Rounding Digits  Prior editions of Standard 550/590 & 551/591 were silent on rounding digits for published ratings  The following items are subject to significant figure rules: – Published ratings (capacity, efficiency, pressure drop; rating conditions) – Pass/fail limits (Tol1, Tol2, Tol3 calculated from published ratings) – Test results (final reported values of measurements and calculated results)

 Table 14 has the required number of significant figures for each value – Generally 3 or 4 sig figs, though temperature is technically 5

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Significant Figures & Rounding Digits  Definition of significant figures: (Section 3.14) Significant Figure. Each of the digits of a number that are used to express it to the required degree of accuracy, starting from the first nonzero digit (Refer to Sections 4.3 and 6.2).

 Detailed rules are in Section 4.3, a brief summary: – – – –

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All non-zero digits are considered significant Leading zeroes are not significant Trailing zeroes to the right of a decimal point are significant Trailing zeroes in a number to the left of a decimal point can be ambiguous, so several methods are defined to present such numbers without ambiguity; the easiest is many cases is to change the prefix on the units of measure (i.e. for large numbers use either W, kW, or MW to avoid trailing zeroes)

Significant Figures

π = 3.14159265359…

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Significant Figures

Rounded Value

1

3

2

3.1

3

3.14

4

3.142

5

3.1416

6

3.14159

AHRI Standards 550/590 (I-P)-2015 and 551/591 (SI)-2015 define rules for significant figures and rounding in Section 4.

Rounding Error  Rounding error can be up to ±½ digit beyond the least significant digit (last digit moving to the right)  Example: – – – –

Take the number 2.5 with two significant digits The least significant digit is “5” ±½ of the next digit is ±0.05 Result “2.5” may have come from a value ranging from 2.4500000… to 2.5499999… – The rounding error could be up to ±0.05, or (±0.05)/2.5 = ±2.0%

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Rounding Error 2 Significant Figures  Evaluating rounding error over several orders of magnitude there is a clear pattern:

With only 2 significant figures, the rounding error ranges from 0.50% to 5.0%

0.50% < 𝜖 ≤ 5.0%

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With 3 significant figures, the rounding error ranges from 0.050% to 0.50%

0.050% < 𝜖 ≤ 0.50%

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With 4 significant figures, the rounding error ranges from 0.0050% to 0.050%

0.0050% < 𝜖 ≤ 0.050%

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Acceptance Criteria Issues  If an acceptance criteria includes a tolerance on the order of magnitude of 5% (such as for a chiller with ΔT=10°F where Tol1=5.0% at full load), then a rounding error of 0.5% becomes a significant issue to consider

±0.5 = ±10% 5.0

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Examples  The next few slides walk through some examples that demonstrate the impact of rounding issues – First showing how a rating software program might calculate an efficiency value, which is then rounded to the published rating value – Next showing how the tolerance limit is calculated from the published rating, and then rounded to established the pass/fail criterion for a test – Next showing how a test result calculated from test measurements is rounded and used to determine pass/fail

 The example starts from very coarse resolution, then moving towards finer resolution that demonstrates why AHRI Standards 550/590 and 551/591 selected the required significant figures shown in Table 14 27

Example Using Efficiency (EER)  As a gross example, if rounding to the nearest integer, these are the only possible values for rated efficiency, or Tol1 tolerance limit, or for tested efficiency … 8 9 10 11 12 13 14 …

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Example Using Efficiency (EER)  Rating program calculates EER = 11.1449999  If rounding to the nearest integer (not using significant figures): full load ΔT capacity load point Tol1 tolerance

published rating rounds to 11 Tol1 calculated from 11 Min Allowed EERtested =EERrated-Tol1 Min Allowed EERtested = 10.47619048 Min Allowed EERtested result rounds to 10

12

11

RATED VALUE

10

MIN ALLOWED

9.5

9.0

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10 °F 100% 5.00%

𝑀𝑖𝑛 𝐴𝑙𝑙𝑜𝑤𝑒𝑑 𝐸𝐸𝑅𝑡𝑒𝑠𝑡𝑒𝑑 =Round

𝐸𝐸𝑅𝑟𝑎𝑡𝑒𝑑 , 0 digits 1 + 𝑇𝑜𝑙1

Example Using Efficiency (EER)  Rating program calculates EER = 11.1449999  If rounding to the nearest integer (not using significant figures):

12

11

10 9.5

9.0

30

Due to rounding the limit (minimum allowable EER), and rounding of the test result, there is a grey zone where pass-fail is not 100% clear RATED VALUE MIN ALLOWED

Example Using Efficiency (EER)  If using 2 significant figures, these are the only possible values for rated efficiency, or for tested efficiency … 9.0 9.1 9.2 9.3 9.4 9.5 9.6 9.7 9.8 9.9 10 11 12 13 14 …

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Example Using Efficiency (EER)  Rating program calculates EER = 11.1449999  If using 2 significant figures: full load ΔT capacity load point Tol1 tolerance

published rating rounds to 11 Tol1 calculated from 11 Min Allowed EERtested =EERrated-Tol1 Min Allowed EERtested = 10.47619048 Min Allowed EERtested result rounds to 10

12

11

RATED VALUE

10

MIN ALLOWED

9.5

9.0

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10 °F 100% 5.00%

𝑀𝑖𝑛 𝐴𝑙𝑙𝑜𝑤𝑒𝑑 𝐸𝐸𝑅𝑡𝑒𝑠𝑡𝑒𝑑 =Round

𝐸𝐸𝑅𝑟𝑎𝑡𝑒𝑑 , 2 sig figs 1 + 𝑇𝑜𝑙1

Example Using Efficiency (EER)  Rating program calculates EER = 11.1449999  If using 2 significant figures:

12

11

10 9.5

9.0

33

Due to rounding the limit (minimum allowable EER), and rounding of the test result, there is a grey zone where pass-fail is not 100% clear RATED VALUE MIN ALLOWED


error bars show the uncertainty due to rounding (lack of resolution)

pass 12

pass

11

RATED VALUE MIN ALLOWED

10

POSSIBLE TEST POINTS 9.5

pass (but 9% possibility it is a wrong conclusion)

9.0

fail

fail 34

10 °F 100% 5.00%



11.1

pass pass

10.8

RATED VALUE MIN ALLOWED

10.7

POSSIBLE TEST POINTS

10.6 10.5

fail

10.4

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10 °F 100% 5.00%

fail


Example Using Efficiency (EER)  Rating program calculates EER = 11.1449999  If using 3 significant figures: As in the 2 significant figure example, due to rounding the limit (minimum allowable EER), and rounding of the test result, there is a grey zone where pass-fail is not 100% clear. With 3 significant figures the grey zone is smaller, though still sizeable.

fail 36



11.14

RATED VALUE MIN ALLOWED POSSIBLE TEST POINTS

10.61

10.59

fail 37

10 °F 100% 5.00%

10.60

fail

pass

pass

10.62

10.63


Example Using Efficiency (EER)  In previous figures, note that the effective width of the tolerance band was impacted due to rounding (not always exactly equal to Tol1)

parameter units efficiency EER efficiency EER efficiency EER

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rating program published difference significant internal rating due to figures calculation (rounded) rounding 2 3 4

11.1449999 11.1449999 11.1449999

11 11.1 11.14

difference calculated rounded min due to min or max or max rounding allowable allowable for allowable for pass-fail pass-fail limit

-1.30% 10.4761905 -0.40% 10.5714286 -0.04% 10.6095238

10 10.6 10.61

-4.55% 0.27% 0.00%

compounded rounding error for tolerance zone size -115.75% -2.69% -0.81%

Tips for Implementing Significant Figures  Excel formula to round a value to a specified number of sigfigs: =ROUND(value,sigfigs-(1+INT(LOG10(ABS(value)))))

 Excel formula to display a value as text properly formatted to appear with the correct number of sigfigs : =TEXT(TEXT(value,"."&REPT("0",sigfigs)&"E+000"), "0"&REPT(".",(sigfigs-(1+INT(LOG10(ABS(value)))))>0)& REPT("0",(sigfigs-(1+INT(LOG10(ABS(value)))))*((sigfigs(1+INT(LOG10(ABS(value)))))>0))) Note 1: replace “value” and “sigfigs” with either a number or a cell reference Note 2: when “value” is zero, these formulas return an error message (#NUM ) Note 3: similar methods may be used in other programming languages

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Section 5, Rating Requirements

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Section 5.1.2 - Heating Energy Efficiency

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➢

New Efficiency Value - Simultaneous Heating and Cooling Coefficient of Performance (COPSCH)

➢

Equation 6: COPSCH = Qcd + Qev/K3∙Winput

AHRI 2011 Rating Conditions  Standard rating conditions – cooling mode IP AHRI 550/590-2011

SI AHRI 551/591-2011

fixed (specified) fixed (reference only) variable

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New AHRI 2015 Rating Conditions  Standard rating conditions – cooling mode IP AHRI 550/590-2015

SI AHRI 551/591-2015

fixed (specified) fixed (reference only) variable

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Section 5.2 - Standard Ratings and Conditions - Why the change? ➢ ➢

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An error was discovered in the implementation of the ASHRAE 90.1 Kadj formula. The calculated value for Kadj does not equal 1.00 at Standard Rating Conditions (SRC) for all cases. –

IP: At one particular efficiency level Kadj is indeed equal to 1.00, but chiller models at lower or higher efficiency levels result in values that deviate from 1.00.

–

SI: There is a small but constant error regardless of chiller efficiency due to slightly different standard rating conditions defined for SI and IP

Section 5.3 - Application Rating Conditions ➢

Full and Part-load Application Rating Conditions ➢ Table 2

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–

No changes to ranges from 2011 Standard

–

Additional notes have been added to clarify the intent of the application rating conditions

Section 5.4 – Part-Load Ratings ➢

Table 3, Part-load Conditions for Rating, Changes –

New Clarification for Note 6:

“Air-cooled and evaporatively-cooled unit ratings are at standard atmospheric condition (sea level). Measured data shall be corrected to standard atmospheric pressure of 14.696 psia per Appendix F.”

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Section 5.4 – Part-Load Ratings ➢

IPLV & NPLV Nomenclature –

It is important to identify which standard was used to determine ratings because the IP & SI Standard Rating Conditions are not exact conversions

–

IPLV or NPLV should be appended with “.SI” or “.IP”

IPLV.SI IPLV.IP –

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NPLV applies only to Water-Cooled chillers

Section 5.4.1.2 - Stepped Capacity Part Load Ratings ➢

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IPLV –

If a chiller can not operate at a defined part load point, the point may be interpolated, but not extrapolated

–

In cases where the equipment cannot unload to obtain a point, 5.4.1 and the subsections provide numerous examples of various types to calculate IPLV

Section 5.6, Table 12 - Definition of Operating Condition Tolerances and Stability Criteria ➢

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For testing, each stability criteria has been statistically defined

Section 5.6.3, Table 13 - Definition of Validity Tolerance ➢

Energy Balance (Tol4) tolerance reduced by 30% ➢ New requirement for Voltage Balance (Vbal) of ≤ 2.0% between phases

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Section 6, Minimum Data Requirements for Published Ratings

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Section 6.1 - Minimum Data Requirements for Published Ratings  Clarifies that Standard Ratings are per Section 5.1 (Standard Rating Metrics) and Section 5.2 (Standard Ratings and Conditions)  Adds direction for centrifugal chillers to use Section 5.3 (Application Rating Conditions) with the Fouling Factor Allowance per Table 1 Notes unless the specified application states a different value.

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Section 6.2 - Published Ratings  Requires all Published Ratings to be rounded to the number of significant figures shown in Table 14 (effective 1/1/17)  Rated Total Input Power to Chiller (6.2.1.4) – Explicitly includes all auxiliary power (previously only stated in testing requirements). – Include losses from starters, transformers, drives, or gearboxes (line side power measurement) when those components are provided by the chiller manufacturer (whether unit-mounted, selfcontained, free-standing, or remote-mounted). – Include losses from non-electric drive (prime mover and all driveline components) when those components are provided by the chiller manufacturer. – Excludes losses (not included in the ratings) from starters, transformers, drives, gearboxes, or prime mover when such equipment is provided by the customer or other third party. If variable speed, assume same speed control method as if provided by the chiller manufacturer.

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Section 6.2 - Published Ratings (cont’d)  Fouling Factor Allowances per Table 1 or Table 2 (either Standard or Application Rating Conditions, as applicable)  Water Cooled Condensers (6.2.2) – Requires ECWT and LCWT, or LCWT and ΔT

 Air-cooled (6.2.3) and evaporatively-cooled (6.2.4) condensers. Rated altitude for application rating conditions (defines the atmospheric pressure associated with the rating). Standard ratings are still at sea level. Fan power and spray pump power are now optional itemizations (as subsets of the total input power)

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Section 6.3 - Summary Table of Data to be Published    

55

Added column for significant figures requirement Required reporting of altitude Optional itemization notes (fan, spray pump) Temperature decimal place rounding requirements

Section 7, Conversions and Calculations

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Conversion Factors – 550/590

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Conversion Factors – 551/591

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Water Side Properties Calculation Methods  Either of the following 2 methods can be used. In both cases, the value of the water temperature or pressure to be used as input is dependent on the context of the calculation using the density and specific heat terms.

59

Method 1  Use NIST (National Institute of Standards and Technology) Refprop software (version 9.1 or later) to calculate physical properties density and specific heat, as a function of both pressure and temperature.

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Method 2  Use the following polynomial equations to calculate density and specific heat of water as a function of temperature only.

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Converting Altitude to Atmospheric Pressure  The relationship is based on the International Standard Atmosphere (ISA) and represents a mean value of typical weather variations. The ISA is defined by International Civil Aviation Organization (ICAO). The slight difference between geometric altitude (ZH) and geopotential altitude (H) is ignored for the purposes of this standard (ZH ≅ H).

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Section 8, Symbols and Subscripts

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Symbols and Subscripts  All symbols and subscripts from the standard and all appendices were compiled into a single section  All symbols and subscripts have unique usage  A few new symbols and subscripts were added

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Appendix C, Method of Testing Water-Chilling and Water-Heating Packages Using the Vapor Compression Cycle

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Test Setup

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Test Setup  Installation – No changes

 Data to be collected – Previously listed in text of Appendix C. Now organized in Tables C3, C4, and C5.

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Data to be Recorded (refer to Table C3) Type All Condenser Types

Data to be Recorded During the Test Data Item General Time of day for each data point sample

Water-cooled Condenser Water-cooled Heat Recovery Condenser

Condenser

Air-cooled Condenser

Condenser

Atmospheric pressure Tin Tout mw or Vw Δptest Tin Tout mw or Vw Δptest Spatial average dry-bulb temperature of entering air

Evaporatively-cooled Condenser

Condenser

Spatial average dry-bulb temperature of entering air

°F

Spatial average wet-bulb temperature of entering air

°F

Discharge temperature Discharge pressure Liquid refrigerant temperature entering the expansion device Liquid pressure entering the expansion device

°F psia °F

Winput (and Wrefrig if needed) Voltage for each phase If 3-phase: average voltage Frequency for one phase Refer to Standard for detailed requirements

kW V V Hz

Evaporator

Without Condenser

Compressor Liquid Line

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Units of Measure hh:mm:ss.s

Electric Drive

Chiller

Non-Electric Drive

Chiller

psia °F °F lb/h or gpm psid °F °F lb/h or gpm psid °F

psia

Data to be Recorded (refer to Tables C4 and C5) Table C4. Auxiliary Data to be Recorded Type All

Non-electric Drive

Units of Measure

Data Item Date, place, and time of test

dd-mmm-yyyy hh:mm:ss

Names of test supervisor and witnessing personnel

-

Ambient temperature at test site

°F

Nameplate data including make, model, size, serial number and refrigerant designation number, sufficient to completely identify the water chiller. Unit voltage and frequency shall be recorded.

-

Prime mover nameplate data (motor, engine or turbine).

-

Fuel specification (if applicable) and calorific value

-

Table C5. Optional Auxiliary Data to be Recorded

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Type Open-type compressor

Compressor driver rotational speed

Data Item

Units of Measure rpm

Electric Drive

Current for each phase of electrical input to chiller package

amp

Data to be Recorded – Special Notes  Pressure – Refer to Section C4.1.4 for requirements for Water Pressure Drop measurements. – Appendix G is the procedure for Water Pressure Drop Measurement. • Sections G3 and G4 detail the measurement locations and static pressure tap requirements. Many labs construct special “Appendix G Pipes” in various sizes that meet these requirements and reuse them on multiple tests. • Section G5 details the procedure for correcting for additional static pressure drop due to external piping. This procedure may not be required on every test. Some labs find it advantageous to include the correction calculations in their computerized data acquisition system so it is calculated in real time during the test. Other labs do the correction calculations on the final test results.

 Power – Refer to Section C4.1.5 – Clarified that auxiliary, condenser fan, and condenser spray pump power must be included in Winput , but are not required to be recorded separately.

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Data to be Recorded – Special Notes  Flow – Refer to Section C4.1.3 for details on the requirements for mass flow rate and how to calculate it if volumetric flow rate meters are used. – Flow meter installation location • If using volumetric type flow meter(s), consider installing the flow meter(s) on the flow entering the heat exchanger. Not a requirement but strongly preferred. This avoids the need to make small adjustments in test conditions versus rating conditions (per Section C4.1.3.1). • Also refer to Sections 5.1.3 and 5.1.4 for chiller ratings requirements being based on volumetric flow entering the evaporator or condenser (so that rated flow and test measured flow correspond to the same temperature and density). At low ΔT the adjustment is insignificant, but at higher ΔT, particularly in the condenser at higher temperatures, the adjustment is significant and can be more than 10% of the ±5% tolerance on flow rate.

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Collecting/Recording Data

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Testing Process  Section C6.2.1, General – Unit being tested shall maintain steady state operating conditions and performance for a minimum of 15 minutes. – “A minimum of 30 data point measurements shall be collected and recorded” – Data to be recorded is identified in Tables C3 and C4 – Table C5 data may be recorded but is not mandatory – Each data point measurement shall be time stamped – Time interval between data point measurements shall be uniform in duration, e.g. 30 seconds between each of the minimum 30 measurement data points on a 15 minute duration test – “Intervals between time stamps shall not vary by more than +/- 5% from the average time interval for all data points.” – This means that the time intervals for the minimum 30 measurement data points at an average time interval of 30 seconds can’t vary by more than +/- 1.5 seconds. • For example, – Data point n time stamp 10:25:25.2 (hh:mm:ss.s) – Data point n+1 time stamp shall be between 10:25:53.7 and 10:25:56.7

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Recording Data Rules  What is not allowed: – No longer recording 4 points over a 15 minute period. – No longer using tolerances only for pass/fail criteria.

 What shall be done: – Using software or other recording method to capture time stamped data. – Test must run a minimum of 15 minutes, no maximum. – A minimum of 30 data point measurements to be collected at uniform time intervals. • Intervals between time stamps shall not vary more than +/- 5% • Each data point measurement can represent either individual reading or time averaged value. • If time averaged value is used; whether in hardware or software, the time interval for averaging of the data samples shall not exceed 1/60 of the total test time period.

– Pass/Fail decisions will use a combination of tolerance and stability criteria.

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Table of Parameters using 1/60th Total Time Period

75

Time Interval 1.667% maximum time scale for averaging (sec) 15 15 15 15 15 15

number of data points 30 45 90 150 450 900

total test time (minutes) 15 15 15 15 15 15

data sample interval time (seconds) 30 20 10 6 2 1

30 45 90 150 450 900

30 30 30 30 30 30

60 40 20 12 4 2

30 30 30 30 30 30

30 45 90 150 450 900

60 60 60 60 60 60

120 80 40 24 8 4

60 60 60 60 60 60

1/60

15 Minute Trend Using Time Averaged Values Example of 15 Minute Trend- 30 Points

11

To generate point: Can only time average 15 seconds of data.

10 0

1

2

3

4

5

6

7

8

9

Time in Minutes 15 Minute Trend 7.5 Sec Sampling Rate

76

10

11

12

13

14

15

Testing Process  Section C6.2.1, General – Each measured value, such as temperature or power, may be single reading or a time averaged value from a larger number of data points. • For example, 7 measurement samples on a power meter averaged and used as the measured data point for power. • Note the time interval for averaging of data samples shall not exceed 1/60th of the total test period. For a 15 minute round, this would be 15 seconds

– Steady State or Stability Criteria. • Determination of stability shall be based upon the criteria established in Table 12. • Calculation of the Standard Deviation for each of the measurements identified in Table 12 shall be performed.

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Testing Process  Section C6.2.1, General – Determination of Steady State Operating Conditions is based upon the mean value of the 30 or more data points relative to the target value.

– Steady State Operating Conditions (i.e. Stability Criteria) • Determination of stability shall be based upon the criteria established in Table 12. • Calculation of the Standard Deviation for each of the measurements identified in Table 12 shall be performed. • The calculated standard deviation shall be used to determine if the stability criteria is meet as based upon Table 12.

– Performance • Determination of performance shall be based upon Table 11, Definition of Tolerances and Table 12, Definition of Operating Condition Tolerances and Stability Criteria

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Testing Process  Section C6.2.1, General – Performance • A Test Validity assessment shall be made per Section 5.6.3. – “Measurement values and calculation results shall not deviate more than the validity tolerance limits of Table 13” Table 13. Definition of Validity Tolerances Parameter

Limits

Energy Balance1

Ebal ≤ Tol4 × 100%

Voltage Balance2

Vbal ≤ 2.0%

Related Tolerance Equations3 Tol4 = 0.074 − 0.049 ∙ %Load +

Notes: 1. Energy balance where applicable shall be calculated in accordance with Section C3.4.1. 2. Not applicable to single phase units. Voltage unbalance calculated per Section C3.4.2. 3. %Load and Tol4 are in decimal form.

79

0.105 ∆TFL ∙%Load

26

Testing Process  Section C6.2.1, General – Performance • Section 5.6.1 requires that “tolerance limit for test results for Net Capacity, full and part load Efficiency and Water Pressure Drop shall be determined from Table 11” • All of these values shall be rounded to the number of significant figures in Table 14. • Table 11 tolerance limits are “to be used when testing a unit to verify and confirm performance”

80

Example: Operating Condition Tolerance & Stability Temperature (°F) [IP] data point 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30

81

data set 20 44.1000 44.0813 44.1112 44.1114 44.1328 44.1202 44.1314 44.1641 44.1771 44.2081 44.2049 44.2089 44.2529 44.2607 44.2786 44.2942 44.2723 44.3028 44.3270 44.2941 44.2596 44.2982 44.3087 44.3078 44.2697 44.2761 44.2449 44.2107 44.2131 44.1782

44.00 adjusted target 44.22 sample mean 0.07 sample standard deviation 44.50 tolerance limit for sample mean (upper) 43.50 tolerance limit for sample mean (lower)

0.22 mean to target tolerance limit check 0.07 stability limit check

Table 12 Limits 𝑇 − 𝑇𝑡𝑎𝑟 𝑒𝑡 ≤ 0.50 °F ≤ 0.18 °F

PASS

45.00

PASS 44.50

44.00

43.50

43.00 0

5

10

15

20

25

30


82

data set 21 44.2300 44.2064 44.1851 44.2899 44.2652 44.2305 44.3281 44.3780 44.3988 44.3539 44.3958 44.4039 44.3822 44.5030 44.4316 44.3682 44.4459 44.4444 44.4168 44.3574 44.4187 44.5242 44.4754 44.3846 44.3753 44.4774 44.5416 44.5069 44.4989 44.4357




PASS

45.00

PASS 44.50

44.00

43.50

43.00 0

5

10

15

20

25

30


83

data set 25 44.4000 44.3133 44.3274 44.3829 44.3866 44.4275 44.5461 44.5715 44.5904 44.6930 44.5946 44.7292 44.6674 44.7229 44.6287 44.5161 44.4676 44.5075 44.3936 44.4022 44.3615 44.3284 44.1864 44.1699 44.1253 44.2558 44.2032 44.2334 44.3026 44.4401




PASS

45.00

PASS 44.50

44.00

43.50

43.00 0

5

10

15

20

25

30


84

data set 24 44.0800 44.1947 44.2418 44.2749 44.2513 44.2551 44.2909 44.3965 44.3569 44.4994 44.5967 44.5135 44.6332 44.5413 44.6320 44.6478 44.6737 44.6061 44.6170 44.6478 44.6253 44.6290 44.5881 44.5825 44.6091 44.5754 44.5354 44.5219 44.5343 44.5272




PASS

45.00

PASS 44.50

44.00

43.50

43.00 0

5

10

15

20

25

30


85

data set 22 44.2582 44.3333 44.2943 44.1346 43.9783 43.9860 43.9842 43.8357 43.8367 43.9653 43.8687 43.7899 43.7401 43.6353 43.6322 43.5008 43.5933 43.6849 43.8244 43.9271 44.0006 44.1235 44.1814 44.2043 44.1954 44.2967 44.3790 44.4511 44.4855 44.4910




FAIL

45.00

FAIL 44.50

44.00

43.50

43.00 0

5

10

15

20

25

30


86

data set 19 43.8961 43.8178 43.8553 43.8747 43.9924 44.1124 44.1870 44.2367 44.2371 44.2871 44.3588 44.3161 44.2851 44.1644 44.2556 44.3114 44.4313 44.4104 44.3187 44.2660 44.2278 44.3265 44.3860 44.4641 44.4537 44.3344 44.3918 44.4928 44.3978 44.4110




FAIL

45.00

FAIL 44.50

44.00

43.50

43.00 0

5

10

15

20

25

30


87

data set 23 44.1000 44.2147 44.2618 44.2949 44.2713 44.2751 44.3109 44.4165 44.3769 44.5194 44.6167 44.5335 44.6532 44.5613 44.6520 44.6678 44.6937 44.6261 44.6370 44.6678 44.6453 44.6490 44.6081 44.6025 44.6291 44.5954 44.5554 44.5419 44.5543 44.5472




FAIL

45.00

FAIL 44.50

44.00

43.50

43.00 0

5

10

15

20

25

30

Analyzing Results

88

Section C4.5, Validation  As a part of test validation, the concept previously referred to as “heat balance” is now referred to as “energy balance” to better reflect the true purpose.  Section C4.5.3 includes new requirement to calculate voltage balance per Section C3.4.2 for units that use a multi-phase power supply. ➢ Energy Balance (Tol4) tolerance reduced by 25% ➢ New requirement for Voltage Balance (Vbal) of ≤ 2.0% between phases

89

Analyzing Results  Refer to Section C4.3, Tolerances. – Section C4.3.1 defines tolerance requirements on Operating Conditions and refers to Table 12. • Changes related to continuous data collection – Operating Condition Tolerance Limits for measured data are now based on average value for each measurement – Stability Criteria added, based on standard deviation.

– Section C4.3.2 defines requirements on performance and refers to Table 11 – Section 5.6.3 defines requirements for Test Validity and refers to Table 13

90

Analyzing Results (Air-Cooled Chillers) Test Passed

Does test meet validity tolerances in Table 13?

YES

Do air temperature tolerances meet Table E2?

YES

Do operating tolerances and stability meet Table 12?

90

VALID TEST

NO

NO

NO

NO

RE-RUN TEST

YES

Do performance tolerances meet Table 11

Test Failed

Analyzing Results (Water-Cooled Chillers) Test Passed

Does test meet validity tolerances in Table 13?

YES

Do operating tolerances and stability meet Table 12?

90

VALID TEST

Do performance tolerances meet Table 11

NO

NO

NO

RE-RUN TEST

YES

Test Failed

Table 12, Definition of Operating Condition Tolerances and Stability Criteria Table 12. Definition of Operating Condition Tolerances and Stability Criteria

Measurement or Calculation Result

Applicable Operating Mode(s)

Net Capacity, Q (Cooling or Heating)

Cooling, Heating, Heat Recovery

Values Calculated from Data Samples Operating Condition Tolerance Limits Std Mean Dev Unit with Continuous Unloading: 1 Part Load test capacity shall be within 2% of the target part-load capacity2 Q − Q target ≤ 2.000% Q100% Units with Discrete Capacity Steps: Part Load test points shall be taken as close as practical to the specified part-load rating points as stated in Table 3

Cooling Mode Evaporator Entering Water Temperature Leaving Water Temperature

93

ഥ T

sT

No Requirement

sT ≤ 0.18 °F

Only during defrost portion of cycle: sT ≤ 0.50 °F ഥ − Ttarget ≤ 2.00 °F T The target set point condenser entering temperatures (Figure 1) for continuous unloading units will be determined at the target part-load test point. The ± 2.0% tolerance shall be calculated as 2.0% of the full load rated capacity (tonR). For example, a nominal 50.0% part load point shall be tested between 48.0% and 52.0% of the full load capacity to be used directly for IPLV.IP and NPLV.IP calculations. Outside this tolerance, interpolation shall be used..

Entering Water Temperature 1. 2.


No Requirement ഥ T − Ttarget ≤ 0.50 °F Exception for heating mode only: no requirement during defrost portion.

Stability Criteria

Heating

Table 12, Definition of Operating Condition Tolerances and Stability Criteria Table 12. Definition of Operating Condition Tolerances and Stability Criteria Values Calculated from Operating Condition Tolerance Measurement or Calculation Result Applicable Operating Mode(s) Data Samples Limits Mean Std Dev Cooling Mode Heat Rejection Heat Exchanger (Condenser) Entering Water Temperature Cooling ഥ ഥ − Ttarget ≤ 0.50 °F T sT T Leaving Water or Fluid Temperature Heating, Heat Recovery

Cooling Mode Heat Rejection Heat Exchanger (Condenser) Cooling, Heating (non-frosting)

Entering Air Mean Dry Bulb Temperature3

Cooling, Heating (non-frosting)

3. 4.

94

sT ≤ 0.18 °F

ഥ − Ttarget ≤ 1.00 °F T

sT ≤ 0.75 °F

Heating portion: ഥ T − Ttarget ≤ 2.00 °F

Heating portion: sT ≤ 1.00 °F

Defrost portion: ഥ no requirement for T

Defrost portion: sT ≤ 2.50 °F

Heating (frosting)4 ഥ T

Entering Air Mean Wet Bulb Temperature3

Stability Criteria

Heating (frosting)4

sT


sT ≤ 0.50 °F

Heating portion: ഥ − Ttarget ≤ 1.50 °F T

Heating portion: sT ≤ 0.75 °F

Defrost portion: ഥ no requirement for T

No requirement

The “heat portion” shall apply when the unit is in the heating mode except for the first ten minutes after terminating a defrost cycle. The “defrost portion” shall include the defrost cycle plus the first ten minutes after terminating the defrost cycle. When computing average air temperatures for heating mode tests, omit data samples collected during the defrost portion of the cycle.




Values Calculated from Data Samples

Mean Water Flow (Volumetric, Entering) Voltage5 (if multiphase, this is the average of all phases) Frequency5 5.

95

Operating Condition Tolerance Limits

Stability Criteria

Std Dev


ഥ𝑤 V

sVw

V𝑤 − Vw,target ≤ 5.000% Vw,target

sV ≤ 0.750% 𝑉


ഥ V

sV

ഥ − Vtarget V ≤ 10.00% Vtarget

sV ≤ 0.500% 𝑉

sω ω ഥ − ωtarget ≤ 0.500% ≤ 1.000% ω ഥ ωtarget For electrically driven machines, voltage and frequency shall be maintained at the nameplate rating values within tolerance limits and stability criteria on voltage and frequency when measured at the locations specified at Appendix C. For dual nameplate voltage ratings, tests shall be performed at the lower of the two voltages. Cooling, Heating, Heat Recovery

sω




Values Calculated from Data Samples

Mean Condenserless Refrigerant Saturated Discharge Temperature Condenserless Liquid Temperature Steam Turbine

Pressure/Vacuum6

Gas Turbine Inlet Gas Pressure6 Governor Control Compressor Speed7 6. 7.

96

Operating Condition Tolerance Limits

Stability Criteria

Std Dev

Cooling

ഥ T

sT


sT ≤ 0.25 °F

Cooling

ഥ T

sT


sT ≤ 0.50 °F

Cooling, Heating, Heat Recovery Cooling, Heating, Heat Recovery

p

sp

p − prating ≤ 0.500 psid

sp ≤ 0.250 psid

p

sp

p − prating ≤ 0.500 psid

sp ≤ 0.250 psid

sn n − ntarget ≤ 0.250% ≤ 0.500% 𝑛 ntarget For steam turbine and gas turbine drive machines the pressure shall be maintained at the nameplate rating values within the tolerance limits. For speed controlled compressors the speed shall be maintained at the nameplate rating value within the tolerance limits. Cooling, Heating, Heat Recovery

n

sn

Capacity

Table 11, Definition of Tolerances Table 11. Definition of Tolerances Limits Full Load minimum: 100%- Tol1 Full Load maximum: Cooling or heating capacity for units with continuous unloading1 100%+ Tol1 Cooling or heating capacity for units with discrete capacity steps

EER kW/tonR

Efficiency

COP

Water Pressure Drop

IPLV.IP NPLV.IP EER IPLV.IP NPLV.IP kW/tonR IPLV.IP NPLV.IP COPR

Related Tolerance Equations2,3

Tol1 = 0.105 − 0.07 ∙ %Load 0.15 + 23 ∆TFL ∙ %Load

Full Load minimum: 100% - Tol1 Full load maximum: no limit (Full Load shall be at the maximum stage of capacity) Minimum of: (rated EER) / (100%+ Tol1) Maximum of: (100%+ Tol1)·(rated kW/tonR) Minimum of: (rated COP) / (100%+ Tol1) Minimum of: (rated EER) / (100%+ Tol2)

∆TFL = Difference between entering and leaving water temperature at full-load, F See Figure 3 for graphical representation of the Tol1 tolerance.

Tol2 0.35 24 ∆TFL See Figure 4 for graphical representation of the Tol2 tolerance.

= 0.065 + Maximum of: (100%+ Tol2)·(rated kW/tonR) Minimum of: (rated COPR) / (100%+ Tol2) ∆pcorrected ≤ Tol3

Tol3 = max ቊ

1.15 ∙ ∆prated ∆prated + 2 ft H2 O

Notes: 1. The target set point condenser entering temperatures (Figure 1) for continuous unloading units will be determined at the target part load test point. 2. For air-cooled units and evaporatively-cooled units, all tolerances are computed for values after the atmospheric correction is taken into account. 3. %Load, Tol1 and Tol2 are in decimal form.

97

25

Table 13, Definition of Validity Tolerances

Table 13. Definition of Validity Tolerances Parameter

Limits

Energy Balance1

Ebal ≤ Tol4 × 100%

Voltage Balance2

Vbal ≤ 2.0%

Related Tolerance Equations3 Tol4 = 0.074 − 0.049 ∙ %Load +

Notes: 1. Energy balance where applicable shall be calculated in accordance with Section C3.4.1. 2. Not applicable to single phase units. Voltage unbalance calculated per Section C3.4.2. 3. %Load and Tol4 are in decimal form.

98

0.105 ∆TFL ∙%Load

26

Tolerance and Stability Where to Find It Parameter Water Temps Flow Rates Power Voltage Average of ALL Phases Frequency Volts A Volts B Volts C Mean Air Temp Thermopiles Psychrometer Differential Pressure Wet Bulb Atmospheric Pressure Ambient Temp at Site Voltage Unbalance Capacity Efficiency Water Pressure Drop IPLV Energy Balance

99

Measured Calculated X X X X X X X X X X X X X X X

Table 11 Table 12 Table 12 Table 13 Table E2 Tol. Tol. Stab. Tol. Tol. X X X X X X

X X

X

X

X

X

X X X

X

X X X X X X

X X X X X

X

X

Test Report Requirements  A written or electronic test report shall be generated including items for each test point at a specific load and set of operating conditions. AHRI breaks this down into 3 main parts. – Data • Include mean and standard deviation for each measurement value (refer to Section C7.1)

– Calculations • Refer to Section C7.2

– Results • Refer to Section C7.3 and Table C6

 Examples of each will follow

100

Sample Water Cooled Test Report Page 1 – Cooling Mode WATER COOLED AHRI TEST REPORT DATA Date Place of Test Test Supervisor Model Number Unit Voltage Refrigerant Test Time Period Ambient Temperature

Time of Test Witness Personnel Serial Number Unit Frequency Motor Nameplate # Data Point Measurements Atmosheric Pressure(psia)

Design Evaporator Water In Evaporator Water Out Evaporator Delta T Evaporator GPM Evaporator Delta P test (psid) Condenser In Condenser Out Condenser Delta T Condenser GPM Condenser Delta P test (psid) Power (W input) Frequency Voltage A Voltage B Voltage C Voltage Average of all Phases

101

Mean

Standard Standard STDEV Tolerance STDEV

Sample Water Cooled Test Report Page 2 – Cooling Mode Caculations Design

Mean


Evaporator Capacity Gross Density Gross Specific Heat Gross Mass Flow Gross Evaporator Capacity Net Density Net Specific Heat Net Mass Flow Net Condenser Capacity Gross Density Gross Specific Heat Gross Mass Flow Gross Evaporator Delta P adjustment (ft H2O) Condenser Delta P adjustment(ft H2O) Results Design Power (W input) Evaporator Capacity Net Efficiency Evaporator Delta P Corrected(ft H2O) Condenser Delta P Corrected(ft H2O) Energy Balance Voltage Balance

102

Standard Standard Mean Total STDEV Tolerance STDEV

Sample Air Cooled Test Report Page 1 – Cooling Mode AIR COOLED AHRI TEST REPORT DATA Date Place of Test Test Supervisor Model Number Unit Voltage Refrigerant Test Time Period Ambient Temperature

Time of Test Witness Personnel Serial Number Unit Frequency Motor Nameplate # Data Point Measurements Atmosheric Pressure(psia)

Design Evaporator Water In 1 Evaporator Water In 2 AVG Evaporator Water In Evaporator Water Out 1 Evaporator Water Out 2 AVG Evaporator Water OUT Evaporator Delta T Evaporator GPM 1 Evaporator GPM 2 AVG Evaporator GPM Evaporator Delta P test (psid) Psychrometer 1 Temp Psychrometer 2 Temp Entering Air Mean Dry Bulb Thermopile 1A Thermopile 1B Thermopile 2A Thermopile 2B Air Discharge Thermocouple 1A Air Discharge Thermocouple 1B Air Discharge Thermocouple 2A Air Discharge Thermocouple 2B Power (W input) 1 Power (W input) 2 AVG Power (W input) AVG Frequency AVG Voltage A AVG Voltage B AVG Voltage C Voltage Average of all Phases

103

Mean


Sample Air Cooled Test Report Page 2 – Cooling Mode Caculations Design

Mean


Un-Corrected Evaporator Capacity Net Density Net Specific Heat Net Mass Flow Net Un-Corrected Efficiency Correction Factor CFQ Correction Factor CFN Evaporator Delta P adjustment (ft H2O) Results Design AVG Power (W input) Corrected Evaporator Capacity Net Corrected Efficiency Evaporator Delta P Corrected(ft H2O) Voltage Balance Entering Air Mean Dry Bulb Mean Dry Bulb - Psychrometer 1 Thermopile 1A - Psychrometer 1 Thermopile 1B - Psychrometer 1 Air Discharge TC 1A - Thermopile 1A Air Discharge TC 1B - Thermopile 1B Mean Dry Bulb - Psychrometer 2 Thermopile 2A - Psychrometer 2 Thermopile 2B - Psychrometer 2 Air Discharge TC 2A - Thermopile 2A Air Discharge TC 2B - Thermopile 2B Mean Dry Bulb Varation During Test Entering Water 1 - Entering Water 2 Leaving Water 1 - Leaving Water 2 Evap GPM 1 - Evap GPM 2 Power (W input) 1 - Power (Winput) 2

104

Standard Standard Mean Total STDEV Tolerance STDEV

Calculations & Results to Report Calculations (Section C7.2) Delta Padj Delta Tadj

CFQ CFN Density, specific heat capacity, and mass flow values for capacity calculations Report all values of Q used in energy balance calculations Results (Section C7.3) Net Capacity Corrected Gross Capacity (water-cooled only) Power Input (Winput and Wrefrig as applicable)

Efficiency Delta Pcorrected Energy Balance (water-cooled only) Voltage Balance Note: All values calculated using the mean value of the recorded data as per Section C6.2

105

APPENDIX D, Derivation of Integrated Part-Load Value (IPLV)

106

Appendix D 











107

Appendix D contains details on the derivation of the IPLV as defined by equation 8 and 9 including the weighting factors and ambient rebalance temperatures A single chiller’s design rating condition as defined in table 1 represents the performance at the simultaneous occurrence of both full-load and design ambient conditions which typically are the ASHRAE 1% weather conditions. The design efficiency contains no information representative of the chiller’s operating efficiency at any off-design condition (part-load, reduced ambient). The IPLV metric was developed to create a numerical rating of a single chiller as simulated by 4 distinct operating conditions, established by taking into account blended climate data to incorporate various load and ambient operating conditions. The intent was to create a metric of part-load/reduced ambient efficiency that, in addition to the design rating, can provide a useful means for regulatory bodies to specify minimum chiller efficiency levels and for Engineering firms to compare chillers of like technology. The IPLV value is not intended to be used to predict the annualized energy consumption of a chiller in any specific application or operating conditions. IPLV was intended to be a standard overall rating metric with a weighted full and part load component. NPLV was created to allow for centrifugal chillers to include a PLV metric for chillers that can not operate at full load standard rating conditions, but it has been expanded to cover all water cooled products. Currently it is not a valid metric for air cooled products

Appendix D      

  

108

There are many issues to consider when estimating the efficiency of chillers in actual use. Neither IPLV nor design rating metrics on their own can predict a building’s energy use. Additionally, chiller efficiency is only a single component of many which contribute to the total energy consumption of a chiller plant. In addition chillers are typically used in multiple configurations and are part of an overall chilled water HVAC system. It is for these reasons that AHRI recommends the use of building energy analysis programs, compliant with ASHRAE Standard 140, that are capable of modeling not only the building construction and weather data but also reflect how the building and chiller plant operate. In this way the building designer and operator will better understand the contributions that the chiller and other chiller plant components make to the total chiller plant energy use. Modeling software can also be a useful tool for evaluating different operating sequences for the purpose of obtaining the lowest possible energy usage of the entire chiller plant. To use these tools, a complete operating model of the chiller, over the intended load and operating conditions, should be used. In summary, it is best to use a comprehensive analysis that reflects the actual weather data, building load characteristics, operational hours, economizer capabilities and energy drawn by auxiliaries such as pumps and cooling towers, when calculating the chiller and system efficiency. The intended use of the IPLV (NPLV) rating is to compare the performance of similar technologies, enabling a side-by-side relative comparison, and to provide a second certifiable rating point that can be referenced by energy codes. A single metric, such as design efficiency or IPLV shall not be used to quantify energy savings.

APPENDIX E. Chiller Condenser Entering Air Temperature Measurement

109

Changes To Appendix E for 2015 Version  Table E2 verbiage changed to clarify the use of “average “ values for tolerance specification (location vs. time).  Figure E1 revised to show more detail for construction of air sampling tree.  Thermopiles or individual thermocouples averaged may be used with the air sampling trees.

 For part load test points, “Aspirating Psychrometers” positioned at non operating portions of the coil on the test chiller may be excluded from the calculations.

110

Recirculation Thermocouple

Example Air Sampling Tree Air Sampling Tree MAXIMUM 4 per “Aspirating Psychrometer”. Greater Than 50 Holes.

Thermopiles Each black strip represents a thermocouple.

MINIMUM 16

TREE PLACEMENT 6-12 inches from coil.

Insulated hose of equal lengths connecting to “Aspirating Psychrometer”

111

1 per air sampling tree. Maximum 5 degree F Delta from average air inlet of Psychrometer.

Thermopile Box Thermocouples wired in parallel to provide 1 reading per tree.

Example Aspirating Psychrometer VFD Must maintain 2.5 ft./s or greater Velocity through “Air Sampling Tree ” holes

Temperature Measurement Redundant dry and wet bulb measurements.

112

Additional Information  Mixing fans can be used to ensure adequate air distribution in test room – Rule: Must not point at coil air inlet. Fan exhaust must be 90270 degrees to that of the air inlet of coil.

 Air Sampling Trees – – – – – – –

113

Aspect ratio no greater than 2 to 1 1 main flow trunk 10-20 branch connections Greater than 50 holes Minimum of 16 temperature measurement locations per tree Tree location 6-12 inches from unit Test Setup See figures E3 and E4, Section E6

Additional Information  Aspirating Psychrometers – Fans for Psychrometer can be manual or automatic – Maximum of 4 air sampling trees per psychrometer – Redundant measurement wells for dry and/or wet bulb measurement

114

Appendix F, Atmospheric Pressure Adjustment

115

Appendix F, Atmospheric Pressure Adjustment  Purpose To prescribe a method of adjusting measured test data according to local atmospheric conditions.

 Background To ensure performance can be uniformly compared from one unit and one manufacturer to another, performance testing for air-cooled and evaporatively-cooled chillers should be corrected for air-density variations.

116

Appendix F, Atmospheric Pressure Adjustment  Correction factors based on pressure and not altitude to include effects of weather variations.  Part load correction factors are scaled between 1 and the full load correction based on percentage of full load capacity.  2015 Standard adds method to adjust test data to application conditions.  Correction factor limit changed from 12.23 psia (approx. 5,000 ft) in 2011 Standard to 11.56 psia (approx. 6,500 ft) in 2015 Standard

117

Appendix F, Atmospheric Pressure Adjustment Equations  The values for the correction factor polynomial equation coefficients (AQ, BQ, CQ, Aƞ, Bƞ, and Cƞ) are found in Table F1.  The definitions of all variables are listed in Table 16.

118

DQ = 𝐴𝑄 ∗ 𝑝2 + 𝐵𝑄 ∗ 𝑝 + 𝐶𝑄

𝐶𝐹𝑄

Dη = 𝐴𝜂 ∗ 𝑝2 + 𝐵𝜂 ∗ 𝑝 + 𝐶𝜂

𝐶𝐹𝜂

𝑃=𝑃𝑡𝑒 𝑡


=1+

𝑄𝑒𝑣 ,%𝐿𝑜𝑎 𝑑 ∗ 𝐷𝑄 − 1 ∗ 𝑒 𝑄𝑒𝑣 ,100%

−0.35∗ 𝐷𝜂 ∗𝜂 𝑡𝑒 𝑡 ,100% −9.6

=1+

𝑄𝑒𝑣 ,%𝐿𝑜𝑎 𝑑 ∗ 𝐷𝜂 − 1 ∗ 𝑒 𝑄𝑒𝑣 ,100%

−0.35∗ 𝐷𝜂 ∗𝜂 𝑡𝑒 𝑡 ,100% −9.6

Appendix F, Atmospheric Pressure Adjustment Equations  The capacity correction factor equation term (DQ) is used only in the capacity correction factor equation.  The efficiency correction factor equation term (Dƞ) is used in both correction factor equations. DQ = 𝐴𝑄 ∗ 𝑝2 + 𝐵𝑄 ∗ 𝑝 + 𝐶𝑄

𝐶𝐹𝑄


=1+

𝑄𝑒𝑣 ,%𝐿𝑜𝑎 𝑑 ∗ 𝐷𝑄 − 1 ∗ 𝑒 𝑄𝑒𝑣 ,100%

−0.35∗ 𝐷𝜂 ∗𝜂 𝑡𝑒 𝑡 ,100% −9.6

Dη = 𝐴𝜂 ∗ 𝑝2 + 𝐵𝜂 ∗ 𝑝 + 𝐶𝜂

𝐶𝐹𝜂

119


=1+

𝑄𝑒𝑣 ,%𝐿𝑜𝑎 𝑑 ∗ 𝐷𝜂 − 1 ∗ 𝑒 𝑄𝑒𝑣 ,100%

−0.35∗ 𝐷𝜂 ∗𝜂 𝑡𝑒 𝑡 ,100% −9.6

Appendix F, Atmospheric Pressure Adjustment Equations  The corrected capacity and efficiency are the tested values multiplied by the correction factors.  If efficiency is expressed in kW/tonR, then the tested efficiency should be divided by the correction factor instead of multiplying , but efficiency used in correction factor equations must be in Btu/(W*h).

120

𝑄𝑐𝑜𝑟𝑟𝑒𝑐𝑡𝑒𝑑

, 𝑡𝑎𝑛𝑑𝑎𝑟𝑑

= 𝑄𝑡𝑒

𝑡

∗ 𝐶𝐹𝑄

𝜂𝑐𝑜𝑟𝑟𝑒𝑐𝑡𝑒𝑑


= 𝜂𝑡𝑒

𝑡

∗ 𝐶𝐹𝜂

𝑃=𝑃_𝑡𝑒 𝑡


Appendix F, Atmospheric Pressure Adjustment Application Rating Conditions  To correct test data to application conditions, the data is first corrected to standard conditions then the reverse method is used to correct to the application rated atmospheric pressure (Prated).  The same equations are used for the correction factors, but with the application atmospheric pressure in place of the measured test pressure.  The application capacity and efficiency are the standard condition corrected values divided by the correction factors. 𝑄𝑐𝑜𝑟𝑟𝑒𝑐𝑡𝑒𝑑

121

,𝑎𝑝𝑝𝑙𝑖𝑐𝑎𝑡𝑖𝑜𝑛

=

𝑄𝑐𝑜𝑟𝑟𝑒𝑐𝑡𝑒𝑑 𝐶𝐹𝑄


𝑃=𝑃𝑟𝑎𝑡𝑒𝑑

𝜂𝑐𝑜𝑟𝑟𝑒𝑐𝑡𝑒𝑑,𝑎𝑝𝑝𝑙𝑖𝑐𝑎𝑡𝑖𝑜𝑛 =

𝜂𝑐𝑜𝑟𝑟𝑒𝑐𝑡𝑒𝑑,𝑠𝑡𝑎𝑛𝑑𝑎𝑟𝑑 𝐶𝐹𝜂

𝑃=𝑃𝑟𝑎𝑡𝑒𝑑

Appendix F, Atmospheric Pressure Adjustment Example – Full Load

122

Appendix F, Atmospheric Pressure Adjustment Example – Part Load

123

Appendix F, Atmospheric Pressure Adjustment Example – Application Conditions

124

Appendix G, Water Pressure Drop Measurement Procedure

125

APPENDIX G, WATER PRESSURE DROP MEASUREMENT PROCEDURE – NORMATIVE  Purpose To prescribe a measurement method for Water Pressure Drop and, when required, a correction method to compensate for friction losses associated with external piping measurement sections. The measurement method only applies to pipe of circular cross section.  Background The aim is to determine measurement uncertainties pertaining to waterside pressure drop (WPD) dictated by the requirement of a certified test point. AHRI website (www.ahrniet.org) provides an excel spreadsheet that can be used for water pressure drop adjustment calculations.

126

APPENDIX G, WATER PRESSURE DROP MEASUREMENT PROCEDURE – NORMATIVE  Static pressure (SP) taps in external upstream/downstream piping shall be used to measure chiller WPD  Adjustment factors are used to compensate/correct pressure drop measurement. However, many studies recommend the restriction of the use of external correction factors because they can be source of potential errors.  It is recommended to use straight pipe connections, with adequate length, for small connection sizes to minimize SP measurements errors 127

Appendix G, Water Pressure Drop Measurement Procedure – Normative  Larger chillers, with large connection sizes, may use elbows/reducers/ enlargers, upstream/downstream, to accommodate pipe diameter changes. It’s a compromise between measurement uncertainties and costs of test facilities.

128

Appendix G, Water Pressure Drop Measurement Procedure – Normative

129

Appendix G, Water Pressure Drop Measurement Procedure – Normative

130

Measurement Locations  SP taps may be located in the unit connections (nozzles) if long enough to meet L/D requirements of Table G1, or in external piping (test fixtures).  External piping arrangement shall use rigid pipe. Flexible hose is not allowed between the unit connections and the pressure taps.

131

Geometrical Requirements for Location of SP Pressure Taps as per Table G1:

132

Static Pressure Taps  Static pressure taps will be in a piezometer ring or piezometer manifold arrangement with a minimum of 3 taps located circumferentially around the pipe, all taps at equal angle spacing.

 To avoid introducing measurement errors from recirculating flow within the piezometer ring, each of the pipe tap holes shall have a flow resistance that is greater than or equal to 5 times the flow resistance of the piezometer ring piping connections between any pair of pressure taps.

133

Static Pressure Taps (contin.)  A “Triple-Tee” manifold arrangement using 4 pipe tap holes is the preferred arrangement, but not required if meeting the flow resistance requirement.

134

Appendix G. Water Pressure Drop Measurement Calculations Condenser

Evaporator

(only applicable to water-cooled type)

Upstream Pipe

Downstream Pipe

Inputs

Inputs

Straight Flow Pressure Drop

Expansions and Reduction Pressure Drop

Elbow Pressure Drop



Downstream Pipe

Inputs

Elbow Pressure Drop

෍

Maximum Pressure Drop correction for the Evaporator

135

Upstream Pipe



Inputs

Elbow Pressure Drop



Elbow Pressure Drop

෍

Maximum Pressure Drop correction for the Condenser

Inputs - Water Temperature

- Piping Dimensions

- Flow Rate - Flow Tube Inside Diameter at Static Pressure Measurement Location


Straight Flow Pressure Drop 𝐿 𝑉2 ℎ𝐿 = 𝑓 ∗ ∗ 𝑑 2𝑔

  

136

hL = Pressure Drop f = Darcy Friction Factor g = 32.174 ft/s2 9.80656 m/s2

Elbow Pressure Drop ℎ𝐿 = 𝐾 ∗

𝑉2 ℎ𝐿 = 𝐾 ∗ 2𝑔

  

V = Velocity K = Resistance Coefficient K factor L = Length



𝑉2 2𝑔

d = Greatest pipe inside diameter dimension

Straight Flow Pressure Drop  𝐴𝑟𝑒𝑎 = 𝑉=

𝜋∗d2 4

 𝜈(𝑰𝑷) = 7.222𝐸 −9 ∗ 𝑇 4 − 4.632𝐸 −6 ∗ 𝑇 3 + 1.138𝐸 −3 ∗ 𝑇 2 − 0.1344 ∗ 𝑇 + 7.588 [lb/ft/hr]  𝜈 𝑺𝑰 = 0.413379 ∗ 𝜈 𝑰𝑷 [mPa s]

𝐹𝑙𝑜𝑤𝑅𝑎𝑡𝑒 𝐴𝑟𝑒𝑎

 Re =

(log 𝞮 (rms) (ft)

(m)

Steel

1.8 x 10-4

5.5 x 10-5

Plastic

6.0 x 10-6

1.8 x 10-5

“Pipe roughness values shall be either actual measurements or approximations based on handbook values.” 137

0.25

𝑓=

ρ∗V ∗d ν

Commercial Pipe, New Condition

𝐿 𝑉2 ℎ𝐿 = 𝑓 ∗ ∗ 𝑑 2𝑔

ε 74 +5. 3.7∗d Re0.9

)

2

Expansions and Reduction Pressure Drop 𝑉2 ℎ𝐿 = 𝐾 ∗ 2𝑔

𝐷𝑖𝑎𝑚𝑒𝑡𝑒𝑟 𝑟𝑎𝑡𝑖𝑜 𝛽 = 𝑓(

138

𝑑1 , 𝑑 < 𝑑2 ) 𝑑2 1

Elbow Pressure Drop

𝑉2 ℎ𝐿 = 𝐾 ∗ 2𝑔

139

Accuracy and Calibration 



140

For each instrument device in a measurement system, the calibration process shall identify the range over which the required accuracy can be achieved. AHRI website [www.ahrinet.org] provides an excel spreadsheet which helps determine the range over which the calibration achieves the required accuracy by taking the following steps: 1) Data is plotted to show the residual errors versus the calibration reference standard (represented by the black dots on the example figure below). 2) Table C2 and Equations C24 to C30 explain the method of calculating the prediction interval (represented by the blue lines on the example figure below).

Appendix H, Heating Capacity Test Procedure

141

Appendix H, Heating Capacity Test Procedure – Normative  Purpose To prescribe measurement methods for water-side heating capacity for Air Source Heat Pump Water-heating Packages  General Net Heating Capacity will be determined by water-side measurements – Redundant instrumentation is to be used to check for erroneous measurements – Heat rejection flow rate shall remain constant – Heat rejection flow rate shall be at cooling mode test conditions derived from Table 1 or Table 2 of AHRI Standard 550/590 – All ice or melt must be captured and removed by drain provisions for the duration of the test

142

Appendix H, Heating Capacity Test Procedure – Normative  One of two methods of testing heating capacity shall be used to evaluate heating performance – The “T” test procedure described in Section H3 should be used if test conditions are conducive to frost accumulation – The “S” test procedure described in Section H2 may be tried first • If the “S” test requirements cannot be achieved, heating capacity test shall be conducted using the “T” test procedure

143

Appendix H, Heating Capacity Test Procedure – Normative  Overriding automatic defrost controls is prohibited – Defeating time-adaptive defrost controls shall be done during the official data collection interval. A defrost cycle shall be manually induced – Defrost cycles shall always be terminated by the heat pump’s defrost controls. • Defrost initiation is defined as occurring when the controls alter normal heating operation to eliminate possible accumulations of frost. • Defrost termination is defined as occurring when the controls actuate the first change in converting from defrost operation to normal heating operation.

 “S” Test Procedure – Data to be collected throughout preconditioning and data collection periods • Sampled at equal one minute intervals – Dry-bulb Temperature – Water Vapor content of outdoor side entering air. • Applicable Table 11 non-frosting parameters used to evaluate equilibrium sampled at equal 5 minute intervals

– All data collected, except parameters sampled between a defrost initiation and 10 minutes after defrost termination, shall be used to determine compliance as specified in Table 11 144

Appendix H, Heating Capacity Test Procedure – Normative  “S” Test Procedure – Test Room reconditioning apparatus and equipment under test shall be operated a minimum of 1 hour to attain equilibrium, even if equilibrium is achieved in less than 1 hour. – Ending the preconditioning period with a defrost cycle is recommended for heating capacity tests at low temperatures • If defrost cycle occurs heat pump shall operate for at least 10 minutes after defrost cycle before resuming or initiating data collection.

– When preconditioning is completed, data shall be sampled at equal intervals spanning 5 minutes or less. • Net Heating Capacity (Qcd) shall be evaluated at equal 5 minute intervals • Capacity evaluated at the start of the data collection period (Qcd(τ=0)) shall be saved.

145

Appendix H, Heating Capacity Test Procedure – Normative  “S” Test Procedure

– If preconditioning period ends with a defrost cycle • Suspend data collection immediately prior to completing 30 minute interval where Table 11 tolerances are satisfied if;

– Heat pump undergoes a defrost cycle – Or indoor-side water temperature delta degradation ratio exceeds 0.050 – Or one or more Table 11 non-frosting tolerances are exceeded.

• If “S” test procedure is suspended due to a defrost cycle, the “T” test procedure shall be used • If “S” test procedure is suspended due to degradation ratio exceeding 0.050, the “T” test procedure shall be used. • If one or more Table 11 tolerances is exceeded, another attempt at using the “S” test procedure shall be made as soon as steady state performance is achieved. • If the “S” test procedure is not suspended then sampling shall be terminated after 30 minutes of data collection. – The average of the seven (τ=0,1,2,3,4,5,6) samples of the reported Net Heating Capacity applies.

146

Appendix H, Heating Capacity Test Procedure – Normative  “S” Test Procedure – If preconditioning period does not end with a defrost cycle • Suspend data collection immediately prior to completing 30 minute interval where Table 11 tolerances are satisfied if; – Heat pump undergoes a defrost cycle – Or indoor-side water temperature delta degradation ratio exceeds 0.050 – Or one or more Table 11 non-frosting tolerances are exceeded. • If “S” test procedure is suspended due to a defrost cycle, then another attempt shall be made beginning 10 minutes after termination of the defrost cycle. • If “S” test procedure is suspended due to degradation ratio exceeding 0.050, a defrost cycle should be manually initiated, if possible, and the test reinitiated 10 minutes after the defrost cycle. • If one or more Table 11 tolerances is exceeded, another attempt at using the “S” test procedure shall be made as soon as steady state performance is achieved. • If the “S” test procedure is not suspended then sampling shall be terminated after 30 minutes of data collection. – The average of the seven (τ=0,1,2,3,4,5,6) samples of the reported Net Heating Capacity applies.

147

Accompanying Tools

148

Kadj Efficiency Correction Tool  In ASHRAE 90.1 section 6.4.1.2.1 there is a procedure for adjusting minimum efficiency requirements for full and part load for non-standard rating conditions  The procedure is only applicable for water cooled centrifugal chillers  It allows for equipment not designed to operate at AHRI standard ratings conditions to be tested to verify compliance with minimum efficiency requirements  This is not a requirement for AHRI ratings and certification, but is a procedure that is applicable to chillers and customer ratings and regulation compliance  The procedure is complicated and the tool provide a user friendly way to calculate the adjusted minimum efficiency requirements.  The tool allows for calculation of kadj for the 2004, 2007, 2010, 2013 and 2016 standards for both SI and IP ratings  Note that the applicable standard revision that should be used will depend on the version of ASHRAE 90.1 or IECC that has been adopted by the local building efficiency standard

149

Atmospheric Correction The Atmospheric Correction Tool is designed to assist in converting the altitude of the test location to enable adjusting the test results back to standard atmospheric pressure at sea level •

•

150

The tool implements Section F3 of Appendix F • It calculates the following values based upon the data entered into the form • Capacity Correction Factor DQ • Efficiency Correction Factor – Dƞ • Atmospheric correction factor for capacity - CF • Atmospheric correction factor for efficiency – CFƞ • The tool will calculate adjusted capacity and efficiency for the 100% load and the part load point if part load data is entered. • Corrected test capacity Qcorrected standard • Corrected test efficiency ηcorrected standard To use the tool, one enters • The altitude of the test location • The 100% load test capacity • The 100% load test efficiency • Any part load test capacity to be corrected • Any part load efficiency to be corrected