AHRI Standards 550/590 (I-P)-2015 & 551/591...

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

– Kadj– Atmospheric Correction

2

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

3

Learning Objectives

4

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 websitehttp://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

6

Section 1, Purpose

7

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

8

Section 2, Scope

9

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

11

Section 2, Scope

Shown is the current 2016 ACCL scope for the certification program

Refer to the ACCL Presentation for more details

12

Section 3, Definitions

13

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

14

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

15

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

16

Section 4, Test Requirements

17

Impact of Significant Figures & Rounding on Pass-Fail Acceptance

18

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

19

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:

– 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)

20

Significant Figures

Significant Figures Rounded Value

1 3

2 3.1

3 3.14

4 3.142

5 3.1416

6 3.14159

π = 3.14159265359…

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

21

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%

22

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%

23



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

0.050% < 𝜖 ≤ 0.50%

24



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

0.0050% < 𝜖 ≤ 0.050%

25

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

5.0= ±10%

26

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

…89

1011

12

13

14…

28

9.0

9.5

10

11

12

RATED VALUE

MIN ALLOWED


Rating program calculates EER = 11.1449999

If rounding to the nearest integer (not using significant figures):

full load ΔT 10 °F

capacity load point 100%

Tol1 tolerance 5.00%

published rating rounds to 11Tol1 calculated from 11

Min Allowed EERtested =EERrated-Tol1Min Allowed EERtested = 10.47619048

Min Allowed EERtested result rounds to 10

𝑀𝑖𝑛 𝐴𝑙𝑙𝑜𝑤𝑒𝑑 𝐸𝐸𝑅𝑡𝑒𝑠𝑡𝑒𝑑=Round𝐸𝐸𝑅𝑟𝑎𝑡𝑒𝑑1 + 𝑇𝑜𝑙1

, 0 digits

29



If rounding to the nearest integer (not using significant figures):

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

9.0

9.5

10

11

12

RATED VALUE

MIN ALLOWED

30


If using 2 significant figures, these are the only possible values for rated efficiency, or for tested efficiency

…9.09.19.29.39.49.5

9.69.79.89.910111213

14…

31



If using 2 significant figures:




9.0

9.5

10

11

12

RATED VALUE

MIN ALLOWED

𝑀𝑖𝑛 𝐴𝑙𝑙𝑜𝑤𝑒𝑑 𝐸𝐸𝑅𝑡𝑒𝑠𝑡𝑒𝑑=Round𝐸𝐸𝑅𝑟𝑎𝑡𝑒𝑑1 + 𝑇𝑜𝑙1

, 2 sig figs

32

published rating rounds to 11Tol1 calculated from 11

Min Allowed EERtested =EERrated-Tol1Min Allowed EERtested = 10.47619048

Min Allowed EERtested result rounds to 10




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

9.0

9.5

10

11

12

RATED VALUE

MIN ALLOWED

33

9.0

9.5

10

11

12

RATED VALUE

MIN ALLOWED

POSSIBLE TEST POINTS



If using 2 significant figures:full load ΔT 10 °F



pass (but 9% possibilityit is a wrong conclusion)

failfail

pass

pass

error bars show the uncertainty due to rounding (lack of

resolution)

34




10.4

10.5

10.6

10.7

10.8

11.1

RATED VALUE

MIN ALLOWED


fail

fail

pass (but 50% possibilityit is a wrong conclusion)

pass

pass





resolution)

35




fail

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.

36




10.61

11.14

RATED VALUE

MIN ALLOWED


fail failpass (but 50% possibilityit is a wrong conclusion)

pass pass10.62 10.63

10.6010.59


resolution)




37


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

significant

figures

rating

program

internal

calculation

published

rating

(rounded)

difference

due to

rounding

calculated

min or max

allowable

for pass-fail

rounded min

or max

allowable for

pass-fail

difference

due to

rounding

allowable

limit

compounded

rounding

error for

tolerance

zone size

efficiency EER 2 11.1449999 11 -1.30% 10.4761905 10 -4.55% -115.75%

efficiency EER 3 11.1449999 11.1 -0.40% 10.5714286 10.6 0.27% -2.69%

efficiency EER 4 11.1449999 11.14 -0.04% 10.6095238 10.61 0.00% -0.81%

38

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 referenceNote 2: when “value” is zero, these formulas return an error message (#NUM )Note 3: similar methods may be used in other programming languages

39

Section 5, Rating Requirements

40

Section 5.1.2 - Heating Energy Efficiency

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

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

41

AHRI 2011 Rating Conditions

Standard rating conditions – cooling mode

IPAHRI550/590-2011

SIAHRI551/591-2011

fixed (specified)fixed (reference only)variable

42

New AHRI 2015 Rating Conditions

Standard rating conditions – cooling mode

IPAHRI550/590-2015

SIAHRI551/591-2015

fixed (specified)fixed (reference only)variable

43

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

➢ 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

44

Section 5.3 - Application Rating Conditions

➢ Full and Part-load Application Rating Conditions➢ Table 2

– No changes to ranges from 2011 Standard

– Additional notes have been added to clarify the intent of the

application rating conditions

45

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.”

46

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.SIIPLV.IP

– NPLV applies only to Water-Cooled chillers

47

Section 5.4.1.2 - Stepped Capacity Part Load Ratings

➢ 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

48

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

➢ For testing, each stability criteria has been statistically defined

49

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

50

Section 6, Minimum Data Requirements for Published Ratings

51

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.

52

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, self-contained, 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.

53

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)

54

Section 6.3 - Summary Table of Data to be Published

Added column for significant figures requirement

Required reporting of altitude

Optional itemization notes (fan, spray pump)

Temperature decimal place rounding requirements

55

Section 7, Conversions and Calculations

56

Conversion Factors – 550/590

57

Conversion Factors – 551/591

58

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.

60

Method 2

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

61

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).

62

Section 8, Symbols and Subscripts

63

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

64

Appendix C, Method of Testing Water-Chilling and Water-Heating

Packages Using the Vapor Compression Cycle

65

Test Setup

66

Test Setup

Installation

– No changes

Data to be collected

– Previously listed in text of Appendix C. Now organized in Tables C3, C4, and C5.

67

Data to be Recorded (refer to Table C3)Data to be Recorded During the Test

Type Data Item Units of Measure

All Condenser Types General Time of day for each data point sample hh:mm:ss.s

Atmospheric pressure psia

Evaporator Tin °F

Tout °F

mw or Vw lb/h or gpm

Δptest psid

Water-cooled Condenser Condenser Tin °F

Water-cooled Heat Recovery Condenser Tout °F

mw or Vw lb/h or gpm

Δptest psid

Air-cooled Condenser Condenser Spatial average dry-bulb temperature of entering air °F

Evaporatively-cooled Condenser Condenser Spatial average dry-bulb temperature of entering air °F

Spatial average wet-bulb temperature of entering air °F

Without Condenser Compressor Discharge temperature °F

Discharge pressure psia

Liquid Line Liquid refrigerant temperature entering the expansion

device

°F

Liquid pressure entering the expansion device psia

Electric Drive Chiller Winput (and Wrefrig if needed) kW

Voltage for each phase V

If 3-phase: average voltage V

Frequency for one phase Hz

Non-Electric Drive Chiller Refer to Standard for detailed requirements

68

Data to be Recorded (refer to Tables C4 and C5)

Table C4. Auxiliary Data to be Recorded

Type Data ItemUnits of Measure

All 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). -

Non-electric Drive Fuel specification (if applicable) and calorific value -

Table C5. Optional Auxiliary Data to be Recorded

Type Data Item Units of Measure

Open-type compressor Compressor driver rotational speed rpm

Electric Drive Current for each phase of electrical input to chiller package amp

69

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.

70

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.

71

Collecting/Recording Data

72

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

73

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.

74

Table of Parameters using 1/60th Total Time Period

Time Interval 1/60

1.667%

number of data

points

total test time

(minutes)

data sample

interval time

(seconds)

maximum time

scale for

averaging (sec)

30 15 30 15

45 15 20 15

90 15 10 15

150 15 6 15

450 15 2 15

900 15 1 15

30 30 60 30

45 30 40 30

90 30 20 30

150 30 12 30

450 30 4 30

900 30 2 30

30 60 120 60

45 60 80 60

90 60 40 60

150 60 24 60

450 60 8 60

900 60 4 60

75

15 Minute Trend Using Time Averaged Values

10

11

0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15

Time in Minutes

Example of 15 Minute Trend- 30 Points

15 Minute Trend 7.5 Sec Sampling Rate

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

76

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.

77

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

78

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 Related Tolerance Equations3

Energy Balance1 Ebal ≤ Tol4 × 100% Tol4 = 0.074 − 0.049 ∙ %Load +0.105

∆TFL∙%Load26

Voltage Balance2Vbal ≤ 2.0%

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

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 & StabilityTemperature (°F) [IP]

data data set

point 20

1 44.1000 44.00 adjusted target2 44.0813

3 44.1112 44.22 sample mean4 44.1114 0.07 sample standard deviation

5 44.1328

6 44.1202 44.50 tolerance limit for sample mean (upper)

7 44.1314 43.50 tolerance limit for sample mean (lower)

8 44.1641

9 44.1771 Table 12 Limits

10 44.2081 0.22 mean to target tolerance limit check 0.50 °F

11 44.2049 0.07 stability limit check 0.18 °F

12 44.2089

13 44.2529 PASS

14 44.2607

15 44.2786

16 44.2942

17 44.2723

18 44.3028

19 44.3270

20 44.2941

21 44.2596

22 44.2982

23 44.3087

24 44.3078

25 44.2697

26 44.2761

27 44.2449

28 44.2107

29 44.2131

30 44.1782

43.00

43.50

44.00

44.50

45.00

0 5 10 15 20 25 30

PASS

𝑇 − 𝑇𝑡𝑎𝑟 𝑒𝑡 ≤

≤

81


data data set

point 21

1 44.2300 44.00 adjusted target2 44.2064


5 44.2652



8 44.3780




12 44.4039

13 44.3822 PASS

14 44.5030

15 44.4316

16 44.3682

17 44.4459

18 44.4444

19 44.4168

20 44.3574

21 44.4187

22 44.5242

23 44.4754

24 44.3846

25 44.3753

26 44.4774

27 44.5416

28 44.5069

29 44.4989

30 44.4357

43.00

43.50

44.00

44.50

45.00

0 5 10 15 20 25 30

PASS


≤

82


data data set

point 25

1 44.4000 44.00 adjusted target2 44.3133


5 44.3866



8 44.5715




12 44.7292

13 44.6674 PASS

14 44.7229

15 44.6287

16 44.5161

17 44.4676

18 44.5075

19 44.3936

20 44.4022

21 44.3615

22 44.3284

23 44.1864

24 44.1699

25 44.1253

26 44.2558

27 44.2032

28 44.2334

29 44.3026

30 44.4401

43.00

43.50

44.00

44.50

45.00

0 5 10 15 20 25 30

PASS


≤

83


data data set

point 24

1 44.0800 44.00 adjusted target2 44.1947


5 44.2513



8 44.3965




12 44.5135

13 44.6332 PASS

14 44.5413

15 44.6320

16 44.6478

17 44.6737

18 44.6061

19 44.6170

20 44.6478

21 44.6253

22 44.6290

23 44.5881

24 44.5825

25 44.6091

26 44.5754

27 44.5354

28 44.5219

29 44.5343

30 44.5272

43.00

43.50

44.00

44.50

45.00

0 5 10 15 20 25 30

PASS


≤

84


data data set

point 22

1 44.2582 44.00 adjusted target2 44.3333


5 43.9783



8 43.8357




12 43.7899

13 43.7401 FAIL

14 43.6353

15 43.6322

16 43.5008

17 43.5933

18 43.6849

19 43.8244

20 43.9271

21 44.0006

22 44.1235

23 44.1814

24 44.2043

25 44.1954

26 44.2967

27 44.3790

28 44.4511

29 44.4855

30 44.4910

43.00

43.50

44.00

44.50

45.00

0 5 10 15 20 25 30

FAIL


≤

85


data data set

point 19

1 43.8961 44.00 adjusted target2 43.8178


5 43.9924



8 44.2367




12 44.3161

13 44.2851 FAIL

14 44.1644

15 44.2556

16 44.3114

17 44.4313

18 44.4104

19 44.3187

20 44.2660

21 44.2278

22 44.3265

23 44.3860

24 44.4641

25 44.4537

26 44.3344

27 44.3918

28 44.4928

29 44.3978

30 44.4110

43.00

43.50

44.00

44.50

45.00

0 5 10 15 20 25 30

FAIL


≤

86


data data set

point 23

1 44.1000 44.00 adjusted target2 44.2147


5 44.2713



8 44.4165




12 44.5335

13 44.6532 FAIL

14 44.5613

15 44.6520

16 44.6678

17 44.6937

18 44.6261

19 44.6370

20 44.6678

21 44.6453

22 44.6490

23 44.6081

24 44.6025

25 44.6291

26 44.5954

27 44.5554

28 44.5419

29 44.5543

30 44.5472

43.00

43.50

44.00

44.50

45.00

0 5 10 15 20 25 30

FAIL


≤

87

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

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?

YESVALID TEST

Do performance

tolerances meet

Table 11

Test Passed

Analyzing Results (Air-Cooled Chillers)

NO

NON

O

RE-RUN TEST

90

NO

Test Failed

Does test meet validity tolerances

in Table 13?YES

Do operating tolerances and stability meet

Table 12?

YESVALID TEST

Do performance tolerances meet

Table 11

Test Passed

Analyzing Results (Water-Cooled Chillers)

NO

NO

RE-RUN TEST

90

NO

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)

Values

Calculated from

Data Samples Operating Condition Tolerance LimitsStability

Criteria

MeanStd

Dev

Net Capacity, Q

(Cooling or Heating)Cooling, Heating, Heat Recovery - -

Unit with Continuous Unloading: 1

No

Requirement

Part Load test capacity shall be

within 2% of the target part-load

capacity2

Q − Qtarget

Q100%≤ 2.000%

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

ഥT sT

Entering Water Temperature

Cooling, Heating, Heat Recovery

No Requirement

sT ≤ 0.18 °FLeaving Water Temperature

ഥT − Ttarget ≤ 0.50 °F

Exception for heating mode only: no

requirement during defrost portion.

Entering Water Temperature HeatingOnly during defrost portion of cycle:

ഥT − Ttarget ≤ 2.00 °FsT ≤ 0.50 °F

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. 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..

93



Measurement or Calculation Result Applicable Operating Mode(s)

Values Calculated

from

Data SamplesOperating Condition Tolerance

LimitsStability Criteria

Mean Std Dev

Cooling Mode Heat Rejection Heat Exchanger (Condenser)

ഥT sT ഥT − Ttarget ≤ 0.50 °F sT ≤ 0.18 °FEntering Water Temperature Cooling

Leaving Water or Fluid Temperature Heating, Heat Recovery

Cooling Mode Heat Rejection Heat Exchanger (Condenser)

ഥT sT

Entering Air Mean Dry Bulb

Temperature3

Cooling, Heating (non-frosting) ഥT − Ttarget ≤ 1.00 °F sT ≤ 0.75 °F

Heating (frosting)4

Heating portion:ഥT − Ttarget ≤ 2.00 °F

Heating portion:

sT ≤ 1.00 °F

Defrost portion:

no requirement for ഥTDefrost portion:

sT ≤ 2.50 °F

Entering Air Mean Wet Bulb

Temperature3

Cooling, Heating (non-frosting) ഥT − Ttarget ≤ 1.00 °F sT ≤ 0.50 °F

Heating (frosting)4

Heating portion:ഥT − Ttarget ≤ 1.50 °F

Heating portion:

sT ≤ 0.75 °F

Defrost portion:

no requirement for ഥTNo requirement

3. 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.

4. When computing average air temperatures for heating mode tests, omit data samples collected during the defrost portion of the cycle.

94



Measurement or Calculation ResultApplicable Operating

Mode(s)

Values Calculated from

Data Samples Operating Condition Tolerance


Mean Std Dev

Water Flow

(Volumetric, Entering)Cooling, Heating,

Heat RecoveryഥV𝑤 sVw

V𝑤 − Vw,target

Vw,target≤ 5.000%

sV 𝑉≤ 0.750%

Voltage5

(if multiphase, this is the average of

all phases)

Cooling, Heating,

Heat RecoveryഥV sV

ഥV − Vtarget

Vtarget≤ 10.00%

sV 𝑉≤ 0.500%

Frequency5Cooling, Heating,

Heat Recoverysω

ഥω − ωtarget

ωtarget≤ 1.000%

sωഥω≤ 0.500%

5. 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.

95



Measurement or Calculation ResultApplicable Operating

Mode(s)

Values Calculated from

Data Samples Operating Condition Tolerance


Mean Std Dev

Condenserless Refrigerant Saturated

Discharge Temperature Cooling ഥT sT ഥT − Ttarget ≤ 0.50 °F sT ≤ 0.25 °F

Condenserless Liquid TemperatureCooling ഥT sT ഥT − Ttarget ≤ 1.00 °F sT ≤ 0.50 °F

Steam Turbine Pressure/Vacuum6 Cooling, Heating,

Heat Recovery p sp p − prating ≤ 0.500 psid sp ≤ 0.250 psid

Gas Turbine Inlet Gas Pressure6 Cooling, Heating,

Heat Recovery p sp p − prating ≤ 0.500 psid sp ≤ 0.250 psid

Governor Control Compressor

Speed7Cooling, Heating,

Heat Recovery n sn

n − ntarget

ntarget≤ 0.500%

sn 𝑛≤ 0.250%

6. For steam turbine and gas turbine drive machines the pressure shall be maintained at the nameplate rating values within the tolerance limits.

7. For speed controlled compressors the speed shall be maintained at the nameplate rating value within the tolerance limits.

96

Table 11, Definition of TolerancesTable 11. Definition of Tolerances

Limits Related Tolerance Equations2,3

Cap

acit

y Cooling or heating capacity for units with

continuous unloading1

Full Load minimum: 100%- Tol1

Full Load maximum:

100%+ Tol1 Tol1= 0.105 − 0.07 ∙ %Load

+0.15

∆TFL ∙ %Load23

∆TFL= Difference between entering and

leaving water temperature at full-load, F

See Figure 3 for graphical representation of the Tol1 tolerance.

Cooling or heating capacity for units with

discrete capacity steps

Full Load minimum: 100% - Tol1

Full load maximum: no limit (Full Load shall

be at the maximum stage of capacity)

Eff

icie

ncy

EERMinimum of:

(rated EER) / (100%+ Tol1)

kW/tonR

Maximum of:

(100%+ Tol1)·(rated kW/tonR)

COPMinimum of:

(rated COP) / (100%+ Tol1)

IPLV.IP

NPLV.IP

EER

Minimum of:

(rated EER) / (100%+ Tol2)Tol2

= 0.065 +0.35

∆TFL24

See Figure 4 for graphical representation

of the Tol2 tolerance.

IPLV.IP

NPLV.IP

kW/tonR

Maximum of:

(100%+ Tol2)·(rated kW/tonR)

IPLV.IP

NPLV.IP

COPR

Minimum of:

(rated COPR) / (100%+ Tol2)

Water Pressure Drop ∆pcorrected≤ Tol3 Tol3 = max ቊ1.15 ∙ ∆prated

∆prated + 2 ft H2O25

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

Table 13, Definition of Validity Tolerances

Table 13. Definition of Validity Tolerances

Parameter Limits Related Tolerance Equations3

Energy Balance1 Ebal ≤ Tol4 × 100% Tol4 = 0.074 − 0.049 ∙ %Load +0.105

∆TFL∙%Load26

Voltage Balance2 Vbal ≤ 2.0%

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

Tolerance and Stability Where to Find It

Parameter Measured Calculated Table 11 Table 12 Table 12 Table 13 Table E2

Tol. Tol. Stab. Tol. Tol.

Water Temps X X X

Flow Rates X X X

Power X

Voltage Average of ALL Phases X X X

Frequency X X X

Volts A X

Volts B X

Volts C X

Mean Air Temp X X X X

Thermopiles X X

Psychrometer X X

Differential Pressure X X

Wet Bulb X X X

Atmospheric Pressure X

Ambient Temp at Site X

Voltage Unbalance X X

Capacity X X X

Efficiency X X

Water Pressure Drop X X

IPLV X X

Energy Balance X X

99

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

Date Time of Test

Place of Test

Test Supervisor Witness Personnel

Model Number Serial Number

Unit Voltage Unit Frequency

Refrigerant Motor Nameplate

Test Time Period # Data Point Measurements

Ambient Temperature Atmosheric Pressure(psia)

Standard Standard

Design Mean STDEV Tolerance STDEV

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 (Winput)

Frequency

Voltage A

Voltage B

Voltage C

Voltage Average of all Phases

DATA

WATER COOLED AHRI TEST REPORT

101

Sample Water Cooled Test Report Page 2 – Cooling Mode

Standard Standard


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)

Standard Standard

Design Mean Total STDEV Tolerance STDEV

Power (Winput)

Evaporator Capacity Net

Efficiency

Evaporator Delta P Corrected(ft H2O)

Condenser Delta P Corrected(ft H2O)

Energy Balance

Voltage Balance

Results

Caculations

102

Sample Air Cooled Test Report Page 1 – Cooling Mode

Date Time of Test

Place of Test

Test Supervisor Witness Personnel

Model Number Serial Number

Unit Voltage Unit Frequency

Refrigerant Motor Nameplate

Test Time Period # Data Point Measurements

Ambient Temperature Atmosheric Pressure(psia)

Standard Standard


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


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 (Winput) 1

Power (Winput) 2

AVG Power (Winput)

AVG Frequency

AVG Voltage A

AVG Voltage B

AVG Voltage C

Voltage Average of all Phases

AIR COOLED AHRI TEST REPORT

DATA

103

Sample Air Cooled Test Report Page 2 – Cooling Mode

Standard Standard


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)

Standard Standard

Design Mean Total STDEV Tolerance STDEV

AVG Power (Winput)

Corrected Evaporator Capacity Net

Corrected Efficiency

Evaporator Delta P Corrected(ft H2O)

Voltage Balance


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 (Winput) 1 - Power (Winput) 2

Caculations

Results

104

Calculations & Results to ReportCalculations (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

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

107

Appendix D

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.

108

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

Example Air Sampling TreeRecirculation Thermocouple1 per air sampling tree.

Maximum 5 degree F Delta from average air inlet of Psychrometer.

Air Sampling TreeMAXIMUM 4 per

“Aspirating Psychrometer”.

Greater Than 50 Holes.

ThermopilesEach black strip

represents a thermocouple.

MINIMUM 16

Thermopile BoxThermocouples wired in

parallel to provide 1 reading per tree.

Insulated hose of

equal lengths

connecting to “Aspirating

Psychrometer”

TREE PLACEMENT6-12 inches from

coil.

111

Example Aspirating Psychrometer

VFDMust 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 90-

270 degrees to that of the air inlet of coil.

Air Sampling Trees– 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

113

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


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


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 AdjustmentEquations

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.

DQ = 𝐴𝑄 ∗ 𝑝2 + 𝐵𝑄 ∗ 𝑝+ 𝐶𝑄

Dη = 𝐴𝜂 ∗ 𝑝2 + 𝐵𝜂 ∗ 𝑝 + 𝐶𝜂

𝐶𝐹𝑄 𝑃=𝑃𝑡𝑒 𝑡= 1 +

𝑄𝑒𝑣 ,%𝐿𝑜𝑎𝑑

𝑄𝑒𝑣 ,100% ∗ 𝐷𝑄 − 1 ∗ 𝑒

−0.35∗ 𝐷𝜂 ∗𝜂𝑡𝑒 𝑡 ,100% −9.6

𝐶𝐹𝜂 𝑃=𝑃𝑡𝑒 𝑡= 1 +


𝑄𝑒𝑣 ,100% ∗ 𝐷𝜂 − 1 ∗ 𝑒

−0.35∗ 𝐷𝜂 ∗𝜂𝑡𝑒 𝑡 ,100% −9.6

118

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.


𝐶𝐹𝑄 𝑃=𝑃𝑡𝑒 𝑡= 1 +


𝑄𝑒𝑣 ,100% ∗ 𝐷𝑄 − 1 ∗ 𝑒

−0.35∗ 𝐷𝜂 ∗𝜂𝑡𝑒 𝑡 ,100% −9.6

DQ = 𝐴𝑄 ∗ 𝑝2 + 𝐵𝑄 ∗ 𝑝+ 𝐶𝑄

Dη = 𝐴𝜂 ∗ 𝑝2 + 𝐵𝜂 ∗ 𝑝 + 𝐶𝜂

𝐶𝐹𝜂 𝑃=𝑃𝑡𝑒 𝑡= 1 +


𝑄𝑒𝑣 ,100% ∗ 𝐷𝜂 − 1 ∗ 𝑒

−0.35∗ 𝐷𝜂 ∗𝜂𝑡𝑒 𝑡 ,100% −9.6

119

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).


𝑄𝑐𝑜𝑟𝑟𝑒𝑐𝑡𝑒𝑑 , 𝑡𝑎𝑛𝑑𝑎𝑟𝑑 = 𝑄𝑡𝑒 𝑡 ∗ 𝐶𝐹𝑄 𝑃=𝑃_𝑡𝑒 𝑡

𝜂𝑐𝑜𝑟𝑟𝑒𝑐𝑡𝑒𝑑 , 𝑡𝑎𝑛𝑑𝑎𝑟𝑑 = 𝜂𝑡𝑒 𝑡 ∗ 𝐶𝐹𝜂 𝑃=𝑃𝑡𝑒 𝑡

120

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.

Appendix F, Atmospheric Pressure AdjustmentApplication Rating Conditions

𝑄𝑐𝑜𝑟𝑟𝑒𝑐𝑡𝑒𝑑 ,𝑎𝑝𝑝𝑙𝑖𝑐𝑎𝑡𝑖𝑜𝑛 =𝑄𝑐𝑜𝑟𝑟𝑒𝑐𝑡𝑒𝑑 , 𝑡𝑎𝑛𝑑𝑎𝑟𝑑

𝐶𝐹𝑄 𝑃=𝑃𝑟𝑎𝑡𝑒𝑑

𝜂𝑐𝑜𝑟𝑟𝑒𝑐𝑡𝑒𝑑,𝑎𝑝𝑝𝑙𝑖𝑐𝑎𝑡𝑖𝑜𝑛 =𝜂𝑐𝑜𝑟𝑟𝑒𝑐𝑡𝑒𝑑,𝑠𝑡𝑎𝑛𝑑𝑎𝑟𝑑

𝐶𝐹𝜂 𝑃=𝑃𝑟𝑎𝑡𝑒𝑑

121

Appendix F, Atmospheric Pressure AdjustmentExample – Full Load

122

Appendix F, Atmospheric Pressure AdjustmentExample – Part Load

123

Appendix F, Atmospheric Pressure AdjustmentExample – 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 water-side 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

http://www.ahrniet.org/

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


129


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 SPPressure 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

Upstream Pipe

Inputs

Straight Flow

Pressure Drop

Expansions and

Reduction Pressure

Drop

Elbow Pressure

Drop

Downstream Pipe

Maximum Pressure Drop correction

for the Evaporator

Evaporator

Inputs

Straight Flow

Pressure Drop

Expansions and

Reduction Pressure

Drop

Elbow Pressure

Drop

Inputs

Straight Flow

Pressure Drop

Expansions and

Reduction Pressure

Drop

Elbow Pressure

Drop

Downstream Pipe

Maximum Pressure Drop correction

for the Condenser

Inputs

Straight Flow

Pressure Drop

Expansions and

Reduction Pressure

Drop

Elbow Pressure

Drop

Upstream Pipe

Appendix G. Water Pressure Drop Measurement Calculations

Condenser(only applicable to water-cooled type)

135

hL = Pressure Drop

f = Darcy Friction Factor

g = 32.174 ft/s2 9.80656 m/s2

V = Velocity

K = Resistance Coefficient K factor

L = Length

d = Greatest pipe inside diameter dimension

Inputs

- Water Temperature - Piping Dimensions

- Flow Rate

- Flow Tube Inside Diameter at Static Pressure Measurement Location

Straight Flow Pressure Drop

ℎ𝐿 = 𝑓 ∗𝐿

𝑑∗𝑉2

2𝑔

Expansions and Reduction Pressure

Drop

ℎ𝐿 = 𝐾 ∗𝑉2

2𝑔

Elbow Pressure Drop


2𝑔

136

Straight Flow Pressure Drop

𝐴𝑟𝑒𝑎 =𝜋∗d2

4

𝑉 =𝐹𝑙𝑜𝑤𝑅𝑎𝑡𝑒

𝐴𝑟𝑒𝑎

Re =ρ∗V ∗d

ν

𝜈(𝑰𝑷) = 7.222𝐸−9 ∗ 𝑇4 − 4.632𝐸−6 ∗𝑇3 + 1.138𝐸−3 ∗ 𝑇2 − 0.1344 ∗ 𝑇 +7.588 [lb/ft/hr]

𝜈 𝑺𝑰 = 0.413379 ∗ 𝜈 𝑰𝑷 [mPa s]

𝑓 =0.25

(logε

3.7∗d+5.

74

Re0.9)2

ℎ𝐿 = 𝑓 ∗𝐿

𝑑∗𝑉2

2𝑔

Commercial Pipe,

New Condition

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

Expansions and Reduction Pressure Drop


2𝑔

𝐷𝑖𝑎𝑚𝑒𝑡𝑒𝑟 𝑟𝑎𝑡𝑖𝑜 𝛽 = 𝑓(𝑑1𝑑2

, 𝑑1 < 𝑑2)

138

Elbow Pressure Drop


2𝑔

139

Accuracy and Calibration

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).

140

http://www.ahrinet.org/

Appendix H, Heating Capacity Test Procedure

141

Appendix H, Heating Capacity Test Procedure –Normative

PurposeTo prescribe measurement methods for water-side heating capacity for Air Source Heat Pump Water-heating Packages

GeneralNet 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


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


“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


“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

150

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• 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

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