1992

STANDARD

for

N TO

1cF KHARY

TCPC/E6%

A II

ABSORPTION

WATER

CHILLING AN])

WATER HEATING

PACKAGES

4301 NORTH FAIRFAX DRIVE ARLINGTON, ViRGINIA 22203

PBPEBT1 F

U.S. UVERNMENT
• Pnce 22..oO

PrtIC4IO U.S.A.

• ... 4.b

®Copyright 1992, by Air-Conditioning and Refngeration Institute

Registered United States Patent and Trademark Office

.

.

IMPORTANT

SAFETY RECOMMENDATIONS

It is strongly recommended that the system be designed, constructed, assembled and

installed in accordance with nationally recognized safety requirements appropriate for

systems covered by this standard.

ARI, as a manufacturer’s trade association, uses its best efforts to develop standards,

employing state-of-the-art and accepted industry practices. However, ARI does not certify

or guarantee safety of any products, components or systems designed, tested, rated,

installed or operated in accordance with these standards or that any tests conducted under

its standards will be non-hazardous or free from risk.
/

j7

\\ \\ TABLE OFkNTENTS RETURN TO

ICF KH-LJBRARY

TCPC/E6-13

SECTION PAGE

Section 1. Purpose 1

Section 2. Scope 1

Section 3. Definitions 1

Section 4. Standard Equipment 3

Section 5. Rating Requirement 4

Section 6. Voluntary Conformance 9

Tables and Figures

Table 1. Part Load Conditions for Rating 3

Figure 1. Allowable Tolerance Curve for Full and Part Load 10

Figure 2. IPLV and APLV Tolerance Curve 10

Appendix A

Standard Requirements For Testing Absorption Water Chilling and Water

Heating Packages

Section Al. Purpose 11

SectionA2. Scope 11

Section A3. Definitions 11

Section A4. Test Method 11

Section A5. Instruments 12

Section A6. Measurements 12

Section A7. Test Procedure 14

Appendix B

Derivation of Integrated Part Load Values (IPLV and APLV)

SectionBi. Purpose 18

Section B2. Scope 18

Section B3. Equation and Definition of Terms 18

Figure Bi. Atlanta ASHRAE Weather Data Bin Hours ... • 20

Figure B2. Atlanta Office Building Cooling Operating Hours 21

Figure B3. Atlanta Office Building Cooling Load Profile 22

Figure B4. IPLV Bin Mechanical Cooling Hours 23

Table Bi. Atlanta Office Building Summary 24

PBIIPERTI F

u.S. ERMT
ARI STANDARD 560-92

ABSORPTION WATER CHILLING AND WATER

HEATING PACKAGES

Section 1. Purpose

1.1. Purpose. The purpose of this

standard is to establish, for absorption

water-chilling and water-heating packages;

definitions, classifications, requirements for

rating, and a description of what

constitutes standard equipment.

1.1.1 Intent. This standard is intended

for the guidance of the industry,

including manufacturers, engineers,

installers, contractors, and users.

1.2. Review. This standard is subject to

review and amendment as the technology

advances.

Section 2. Scope

2.1. Scope. This standard applies to

single-effect steam and hot water operated

water chilling units, double-effect steam

and hot water operated water chilling units,

and double-effect direct-fired (natural gas,

oil, LP gas) water chilling! heating units.

Also included are multiple-effect and

multi-loop cycle absorption water

chiller/heating units. Water is the

refrigerant and LIBR (lithium bromide) the

absorbent. See definitions in Section 3.

2.2 Exclusions. Not included in this

standard are heat pump applications,

exhaust gas fired applications, and nonproduct units especially constructed for

field assembly for co-generation

application.

Section 3. Definitions

3.1 Absorption Water Chilling Package.

A factory designed and prefabricated

single-effect low pressure steam or hot

water operated assembly, or a double-effect

high pressure steam operated dr hot water

operated assembly not necessarily shipped

as a single package, consisting of an

evaporator, absorber, condenser, one or

more generators, one or more solution heat

exchangers, with interconnections and

accessories, used for chilling water.

3.2 Absorption Water Chilling and Hot

Water Heating Package. A factory

designed and prefabricated double-effect

direct-fired assembly, not necessarily

shipped as a single package. Consisting of

an evaporator, absorber, condenser, two

generators, one or more solution heat

exchangers, with interconnections and

accessories, used for chilling or heating

water. Hot water may be provided through

a separate hot water heat exchanger to

provide simultaneous heating and cooling

operation.

3.3 Coefficient of Peiformance (COP). A

ratio calculated by dividing the net cooling

capacity by the heat input rate, both

expressed in consistent units.

3.4 Single-Effect Cycle. Dilute LIBR

(lithium bromide) solution in the generator

is concentrated when water vapor is boiled

off. The water vapor is condensed in the

condenser and returned to the evaporator.

The concentrated LIBR is returned to the

absorber where it can absorb water vapor

flashed off in the evaporator.

3.5 Double Effect Cycle. A high stage

generator using high pressure steam, hot

water, gas or oil as the energy means

1
ARI STANDARD 560-92

releases low pressure water vapor which

operates a low stage generator. Dilute

LIBR solution in both low and high stage

generators is concentrated when water

vapor is boiled off. The water vapor is

condensed in the condenser and returned to

the evaporator. The concentrated LIBR is

returned to the absorber where it can

absorb water vapor flashed off in the

evaporator.

3.6 Fouling Factor. The thermal

resistance due to fouling accumulated on

the water side of the heat transfer surface.

3.6.1 Field Fouling Allowance.

Provision for anticipated fouling during

use.

3.7 High Pressure Steam. Steam

pressures above 15 psig but below 150

psig.

3.8 Low Pressure Steam. Steam pressures

15 psig and below.

3.9 Net Cooling/Heating Capacity. The

net cooling/heating capacity is considered

as the usable capacity to the user’s system.

3.10 Integrated Part Load Value (IPLV).

A single number part-load efficiency figure

of merit calculated per the conditions

described in 5.1.4 referenced to Standard

Rating Conditions.

3.11 Application Part Load Value

(APLV). A single number part-load

efficiency figure of merit calculated per the

conditions described in 5.1.4 referenced to

Selected Application Rating Conditions.

3.12 Published Rating. A statement in the

form of catalogs or computer output of the

assigned values of those performance

characteristics, under stated rating

conditions, by which a unit may be chosen

to fit its application. These values apply to

all units of like nominal size and type

(identification) produced by the same

manufacturer.

3.12.1 Standard Rating. A rating

based on tests performed at Standard

Rating Conditions.

312.2 Application Rating. A rating

based on tests performed at

application rating conditions (other

than Standard Rating Conditions).

3.13 “Shall,” “Should,”

“Recommended,” or “It Is

Recommended.”

3.13.1 Shall. Where “shall” or “shall

not” is used for a provision specified,

that provision is mandatory if

compliance with the standard is

claimed.

3.13.2 Should, Recommended, or It is

Recommended. “Should,”

“Recommended,” or “It Is

Recommended” is used to indicate

provisions which are not mandatory,

but which are desirable as good

practice.

3.14 Water Heating Unit. Hot water can

be provided from either of three circuits.

3.14.1 Through the evaporator

circuit.

3.14.2 Through the absorbercondenser circuit.

3.14.3 Through a separate hot water

heat exchanger.

O

.

2
ARI STANDARD 560-92

Section 4. Standard Equipment

4.1 An absorption water chilling or water

chilling-heating package shall include the

following standard equipment:

1. Absorber

2. Condenser

3. Evaporator

4. Generator - Low stage generator for

single-effect units and low and high

stage generator for double-effect

units.

5. Solution Heat Exchangers

6. Pumps for solution and refrigerant

recirculation

7. Controls

a. Low temperature cut-out

b. Provisions for interlocks to

prevent or stop operation of the

chiller package upon failure of

chilled water flow.

c. Means for electrically protecting

pump motors included in the

package against thermal overload.

Table 1. Part Load Conditions for Rating

TPLV APLV

Cooler (All Types) * 44 F [6.7°C]

100% load LWT 44 F [6.7°C] * Selected LWT

0% load LWT ** 2.4 gpm/ton Same as 100% load

Flow rate (gpm) [0.043 L/s per kW] ** Selected gpni/ton

Field fouling 0.00025

allowance (FFA) As specified

Condenser

(Water-Cooled)

100% load EWT * 85 F [29.4°C] * Selected EWT

0% load EWT *** 60 F [15.6°C] *** 60 F [15.6°C]

Flow rate (gpm) [L/S] ** Refer to Section 5.1 ** Selected gpm/ton

[0.054 L/s per kW] [L/s per kWj

0.00025

FFA As specified

Corrected for field fouling allowance by using the calculation method described in

A7.3

The flow rates (gpm) are to be held constant at full load values for all part load

conditions.

Condenser entering fluid temperature varies linearly from 100% load values to 0%

load values.

LWT, leaving water (liquid) temperature.

EWT, entering water (liquid) temperature.

FFA, field fouling allowance in hr• ft F/Btu [m2• °C/W1

3
ARI STANDARD 560-92

d. Chilled water/heating temperature

controller.

e. Instrument panel.

f. Burner controls and gas/oil train

safeties per U.L. Standards 795

Commercial-Industrial GasHeating Equipment and 726 011

for Direct-Fired Water ChillingHeating Units.

8. Miscellaneous

a. Absorbent charge.

b. Means for removal of non

condensables from chiller.

c. Installation and operating

instructions.

d. Nameplate.

Section 5. Rating Requirement

5.1 Published Ratings. Published ratings

consist of Standard Ratings and application

ratings, whether published in catalogs or as

computer output.

5.1.1 Standard Ratings. All Standard

Ratings shall be expressed in tons [kW]

of refrigeration for water chilling units

and Btuh [kW] for water heating and

direct-fired chiller/heaters and shall be at

the following Standard Rating

Conditions:

Leaving chilled-water temperature -

44 F [6.7°C]

Entering absorber/condenser (cooling)

water temperature - 85 F [29.4°C]

Absorber/condenser water side field

fouling allowance - 0.00025 hr sq ft

F/Thai [0.000044 m2• °C/W]

Cooler (evaporator) water-side field

fouling allowance - 0.00025 hr sq ft

FfBtu [0.000044 m2 °C/W]

Heating (hot water) water-side field

fouling allowance - 0.00025 hr sq ft

F/Btu [0.000044 m2• °C/W]

Chilled water evaporator circuit flow

rate - 2.4 gpm/ton [0.43 L/s per kWj

Absorber/condenser water flow rate,

single effect - 3.6 gpm/ton [.065 L/s per

kWj

Absorber/condenser water flow rate,

double effect - 4.0 gpm [.072 L/s per

kW]

Absorber/condenser water flow rate,

double effect direct-fired - 4.5 gpm/ton,

[.081 L/s per kW]

Heating water flow rate - Manufacturer’s

Choice

Heating water entering temperature -

130 F [54.4°C]

Leaving temperature - 140 F [60.0°C]

Entering gas pressure at burner inlet gas

pressure specified based on type of test

gas as defined in Tables VII and Vifi of

Gas-Fired Central Furnaces (except

Direct Vent Central Furnaces) ANSI

Z21.47-1989.

Entering oil -Manufacturer’s Choice

Heating Value of Fuel - value to be

specified in ratings and must be the

higher heating value.

Heating Value - No 2 oil - 140,000

Btu/gal. [38,971 KJ/L]

5.1.2 Application Ratings. It is .)

4
ART STANDARD 560-92

recommended that application ratings

(ratings determined at other than

Standard Rating Conditions) include

ratings at the following range of

conditions:

Leaving chilled water temperature - 40 to

48 F (increments 2 F or less) [4.4 to 8.9

°C, increments 1°C or less]

Entering condensing (cooling) water - 80

to 90 F (increments 5 F or less) [26.7 to

32.2 °C, increments 3 °C or less]

Condensing (cooling) and absorber water

flow rate limit - 2.8 to 4.5 gpm/ton

[0.05 to 0.081 L/s kW]

Heating water flow rate (double effect

heating cycle) - manufacturer’s standard

gprn/ton [L/s kW]

S team pressure (at steam inlet header

single stage unit) - 0 to 12 psig

(increments 2 psi or less) - [0 to 82.7

kPa gauge, increments 14 kPa or less]

Steam pressure (at steam gauge, inlet

header high stage generator) -

Manufacturer’s standard (increments 15

psi or less)

Entering hot water temperature for hot

water operated units - 240 to 400 F [115

to 204°C]

5.1.2.1 Field Fouling Allowance.

When application ratings are

published, they shall include those

with field fouling allowance as

specified in 5.1.1. Additional

application ratings, or means of

determining these ratings, at other

fouling allowances may also be

published (see 5.2).

5.1.3 Determination ofRatings.

Published ratings shall be determined

from test results in accordance with the

following:

a. Evaporator, condenser, absorber,

and hot water heat exchanger

water-side transfer surfaces shall

be considered clean for testing.

Test will be assumed to reflect a

fouling factor of 0.0000 hr sq ft

FfBtu [0.0000m 2 C/WJ.

b. To determine published rating at

any field allowance from test data

at a fouling factor of 0.0000 hr ft

FfBtu [0.0000 m2 C/W] the

calculations for fouling

adjustments described in

Appendix A shall be used.

5.1.4 Part Load Ratings. Part load

ratings of an absorption water-chilling

package, when presented as typical, shall

be calculated on the basis that:

a. Leaving chilled water temperature V

remains constant at the full load

rating value.

b. Leaving heating water

temperature remains constant at

the full load rating value.

c. Chilled evaporator water flow

rate remains constant at the full

load rating value.

d. Entering absorber/condenser

water temperature varies linearly

with load, decreasing from the

value at the rating condition to 60

F [15.6°C] or minimum

acceptable temperature at zero

load, whichever is greater.

5
ART STANDARD 560-92

e. Condenser and absorber water

flow rate remains constant at the

full load rated value.

f. Cooler and condenser field

fouling allowance remain constant

at the full load rated value.

g. Heating waterflow rate remains

constant at the same full load

rated value.

5.1.4.1 Part load performance of an

absorption water-chilling package

may be presented in three ways:

a. Integrated Part Load Value

(IPLV) which is based on a

Standard Rating Condition.

b. Application Part Load Value

(APLV) which is based on a

Selected Application Rating

Condition.

•c. Separate part load data point(s).

5.1.4.2 IPLV and APLV values shall

be determined by test at the

conditions prescribed in 5.1.4.

5.1.4.3 For water-chilling packages

covered by this standard, part load

values (IPLV or APLV) shall be

calculated as follows:

a. Determine the COP at 100

percent; 75 percent, 50 percent

and 25 percent load points at

the conditions specified in

5.1.4.

b. Use the following equation to

calculate IPLV or APLV:

IPLV or APLV =

.17A+.39B+.33C+.11.D (1)

where A=CO.P at 100%

.B=COP at 75%

COP at 50%

- D=COP at 25%

For derivation of equation (1), see

Appendix B.

5.1.4.4 If the package cannot be

operated at the 25% load point,

operate it at minimum capacity with

the condenser entering water (liquid)

temperature (EWT) corresponding to

25% capacity conditions. Then

calculate COP at the measured kW

divided by 25% of the 100% load•

capacity obtained by test.

5.1.5 Minimum Published Rating Data.

Minimum published rating data shall

include package designation(s), including

pass or baffle arrangements and rated

water flow in gpm [L/sJ.

Each package shall be rated at the

Standard Rating conditions and at any

additional application rating conditions

selected, and the rating at any condition

shall include:

a. Capacity, tons of refrigeration

[kW] and/or heat output, MBH

[kcal/hr].

b. Steam input requirement

(pressure and flow rate) or

equivalent hot water requirements

(entering temperature,

temperature difference, and water

flow rate).

6
ART STANDARD 560-92

c. Leaving chified water

temperature, F [°CJ.

d. Entering condensing (cooling)

water temperature, F [°Cj.

e. Evaporator (cooler) water

pressure drop (inlet to outlet), psi

or ft of water [kPa].

f. Absorber/condenser (cooling)

water pressure drop (inlet to

outlet), psi or ft of water [kPa]

including the cross connecting

piping.

g. Hot water pressure drop through

generator (concentrator), psi or ft

of water [kPa}.

h. Statement of fouling factor

allowances on absorber/condenser

(cooling) water-side, evaporator

(cooler) water-side; and on

heating water-side (direct-fired

units)

i. Leaving heating water

temperature, F [°C] (Direct-fired

units).

j. Heating value of gas, Btu/ft 3

[kcal/m 3J(Direct-fired units).

k. Heating value of oil, Btu/gal

{kcal/L] (Direct-fired units).

1. Consumption rate for gas, MBH

[m3/hr} (Direct-fired units).

m. Consumption rate for oil, GPH

{L/hr] (Direct-fired units).

n. Average electrical power

consumption for all auxiliary

components including solution

and refrigerant pumps, purge,

control panel, burner fan, burner

controls, etc. Power required by

system water pumps shall be

excluded.

5.2 Water-Side Fouling.

5.2.1 Fouling at Standard Rating

Conditions. The choice of a field

fouling allowance of 0.00025 hr sq ft

F/Btu [.000044m 2°CiW] for

evaporators and condensers for the

Standard Rating Condition is the basis

for published rating conditions (see 5.1.1

and 5.1.2.1) and which provide the

selections which anticipate the effect of

typical fouling in evaporators and

absorber/condenser (cooling) water

circuits. Fouling tends to reduce

capacity and increase energy

consumption. An application will remain

wfthin the limits of the field fouling

allowance if acceptable water quality is

maintained by treatment, and the heat

exchanger surfaces are periodically

cleaned.

5.2.2 Additional Fouling. Conditions

such as water hardness, organic material,

suspended solids and/or water velocity

• may necessitate the use of a greater field

• fouling allowance than that provided in

the Standard Rating of equipment.

5.2.3 Adjust,nentsfor Additional

Fouling. Published ratings may include

the effects of additional field fouling

allowance. Suàh ratings shall be

determined by using the method

described in paragraph 5.l.3b.

5.3 Verification of Capacity and Power

Requirements. Where verification of

capacity and power requirements is

required, it shall be by test in accordance

7
ART STANDARD 560-92

with the method set forth in Appendix A to

this standard.

5.4 Publication ofRatings. Wherever

application ratings are published or printed,

they shall include, or be accompanied by,

the Standard Rating, clearly designated as

such, and shall include a statement of the

conditions at which the ratings apply.

5.5 Tolerances.

5.5.1 Allowable Tolerance. The

allowable test tolerance on capacity

(tons) [kW], COP, and heat balance shall

be determined from the following

equation:

Tolerance in percent tons {kWj, COP

or percent heat balance

(U.S. Standard Units DT in F.)

=lO.5%-(0.07x%FL)+

(1500/(DT x % FL))

[SI units DT) in °C]

= 10.5% - (0.07 x % FL) +

(833.3tDT x % FL))

Where FL = Full Load

DT = Difference between entering

and leaving chilled water temperature

at full load, F [°C].

See Figure 1. Allowable Tolerance

Curves for Full and Part Load for

graphical representation only.

5.5.2 Full Load. Published ART ratings

shall be such that any production

package shall, upon test have a full load

capacity not less than 100 percent of its

rated capacity less the allowable

tolerance and a full load COP not less

than 100 percent of its rated COP minus

the allowable tolerance. The allowable

tolerance shall be determined by the

equation specified in 5.5.1.

Water pressure drop in the cooler

absorber and absorber/condenser shall

not exceed 115 percent of rated pressure

drop at rated gpm, [L/s} in those vessels.

The tested total auxiliary power shall be

no more than 5% of the rated auxiliary

power.

Example (Full load): (in U.S. Standard

Units only for clarity)

Rated Full Load Performance

Rated capacity = 100 tons

Rated heat input = 1237 MBH

Cooling DT = IOF

COP=boo X12,000.. 097

1,237,000

Allowable Test Performance:

Tolerance = 10.5 - (.07 x 100) +

(1500)

(lOx l00)=10.5-7÷1.5=5%

Min. allowable capacity = (100 -5) x 100

= 95 tons

Mm. allowable COP =

(100 - 5) x .97 = 0.92

100

Max. heat input at mm. capacity =

95 tons x 12,000 = 1239 MBH

.92 COP 1,000

5.5.3 Part Load. The tolerance on part

load power COP shall be the tolerance

e

e

8
ARI STANDARD 560-92

for COP determined by the equation equation:

specified in 5.5.1.

Allowable Tolerance (percent)

Example (Part Load) (in U.S. Standard = 6.5 + 35tDT DT in F

Units only for clarify) [= 6.5 + 19.4/DTJ DT in °C

Rated Part Load Performance DT as specified in 5.5.1

50% capacity = 50 tons See Figure 2. IPLV and APLV Tolerance

50% heat rate = 700 MBH Curve for graphical representation only.

COP =0.86

Full Load DTp.r = 1OF The single number IPLV and APLV,

calculated for the part load conditions

Allowable Test Performance: which apply, shall not exceed the rated

IPLV or APLV by more than the

Tolerance = 10.5 - (.07 x 50) + (1500) allowed tolerance.

(10 x 50)

= 10.5 - 3.5 + 3 = 10% Section 6. Volimtary Conformance

Mm. allowable COP = (100-10) x 0.86 6.1 Conformance. While conformance

100 with this standard is voluntary,

= 0.82 conformance shall not be claimed or

implied for products or equipment within

5.5.4 IPLV AND APLV Tolerance. The its Purpose (Section 1) and Scope (Section

allowable tolerance on IPLV and APLV 2) unless such claims meet all the

shall be determined by the following requirements of the Standard.

9
ART STANDARD 560-92

I—

z

w 30

w

a

w

C.)

z

a:

Iii

-J

0

I—

15

16

[4

10

z

a: 8 w

-J

0

‘ 6

4.

2

Figure 1. Allowable Tolerance Curves For Full And Part Load

DT (SEE 5.5.1)

Figure 2. LPLV and APLV Tolerance Curve

PERCENT FULL LOAD

01 2 34 5 67 8 9101112

DT1.(SEE 5.5.1) COOLER DTFLAT FULL LOAD. F

10
ARI STANDARD 560-92

Appendix A: Standard Requirements for Testing Absorption Water

Chilling and Water Heating Packages

Section Al. Purpose

Al.l Purpose. The purpose of this

appendix is to prescribe a method of

testing absorption water chilling and water

heating packages to verify capacity and

heat energy requirements at a specific set

of conditions.

It is intended that this testing will occur

where instrumentation and load stability

can be provided.

It is not the intent of this standard to

provide for testing in typical field

installations where steady state conditions

are often difficult to achieve and provisions

for measurement are not made.

Section A2. Scope

A2.l Scope. This appendix applies to

absorption water chilling packages used to

chill or heat water, as defined in Section 3

of this standard.

Section A3. Definitions

A3.l Definitions. Definitions of this

appendix are identical with those in

Section 3 of this standard.

Section A4. Test Method

A4.1 Test Method.

A4.1.l The test will measure net

cooling capacity (tons of refrigeration)

[kWj or net heating capacity (MBH of

heating) [kW] and heat energy input

requirements, at a specific set of

conditions.

A4.l.2 After steady-state conditions

have been established at the specific

set of conditions and within the

tolerance set forth in A7.2, three sets

of data shall be taken, at a minimum of

5-minute intervals. To minimize the

effects of transient conditions, test

readings should be taken as

simultaneously as possible.

A4.1.3 The test shall include a

measurement of the net heat removed

from the water as it passes through the

chilled water or heating water circuit

by determination of the following:

a. Water flow rate.

b. Temperature difference between

entering and leaving water.

A4.l.4 The heat removed from the

chilled water is equal to the product of

the chilled water or heating water flow

rate, the water temperature difference,

the specific heat of water, and the

specific gravity of the water.

A4.1.5 The test shall include the

determination of the absorption chilling

and water heating package heat input

energy. This heat energy shall be

determined by a measurement as

outlined in the test procedure (see A7).

A4.l.6 In addition to the

determination of net heat removed and

heat energy input required, data shall

be taken to prepare a heat balance to

substantiate the validity of the test.

A4.2 Conditions ofHeat Transfer

Surfaces.

11
ARI STANDARD 560-92

A4.2.1 Tests conducted in accordance

with this standard may require cleaning

(in accordance with manufacturer’s

instructions) of the heat transfer

surfaces. The “as-tested 11 water-side

fouling factors shall then be assumed

to be 0.000 hr sq ft F/Btu

[0.0000m 2.°C/WJ.

Section AS. Instruments

A5.1 Instruments shall be selected from

the types listed in ASHRAE Standard 14-

80 Methods of Testing for Rating Positive

Displacement Condensing Units (American

Society of Heating, Refrigerating and AirConditioning Engineers, Inc.).

A5.L1 Accuracy of instruments

selected shall be in accordance with

that specified in ASHRAE Standard

14-80.

A5.l.2 Temperature measurements

shall be made in accordance with

ASHRAE Standard 41-86 Standard

Method for Temperature Measurement

(American Society of Heating,

Refrigerating and Air-Conditioning

Engineers, Inc.).

A5.1.3 Flowmeters shall be

constructed and installed in accordance

with the applicable portion of the latest

edition ASME Fluid Meters--Their

Theory and Applications. Turbine flow

meters may also be used in accordance

with Instrument Society of America

Standard ISA RP31.1977

Specflcation, Installation, and

Calibration of Turbine Flow Meters.

A5.1.4 Electrical instruments scales

should be such that readings will be at

least one-half of full scale deflection,

and other instruments, such as gages

and thermometers should be calibrated

over the range of test readings.

A5.l.5 Flow meters for the

measurement of fuel gas shall conform

to one of the three following standards;

ANSI B109.l-1986, Diaphragm Type

Gas Displacement Meters (500 Cubic

Foot per Hour Capacity and Under),

ANSI B109.2-1986, Diaphragm Type

Gas Displacement Meters (Over 500

Cubic Feet per Hour Capacity), and

ANSI Bl09.3-1986, Rotary Type Gas

Displacement Meters. Flow meters for

fuel oil should be timed weight or the

timed volume method when

instruments should be traced to the

American Society of Mechanical

Engineers (ASME).

A5.1.6 Steam mass flow measurement

should be done by measuring steam

condensate flow. If condensate flow is

measured in an open tank, then a

condensate cooler is recommended to

prevent flashing.

Section A6. Measurements

A6.l Data to be recorded after steadystate conditions have been established:

A6.1.1 Test Data

a. Temperature of water entering

cooler (evaporator), F [°C].

b. Temperature of water leaving

cooler (evaporator), F [°CJ.

c. Temperature of water entering

absorber F [°CJ.

d. Temperature of water leaving

condenser, F [°CJ.

e. Temperature of water entering

absorber/condenser if applicable

(heating cycle) F [°Cj.

.

0

12
ART STANDARD 560-92

f. Temperature of water leaving

absorber/condenser if applicable

(heating cycle) F [°C].

g. Cooler (evaporator) water flow

rate, gpm or lb/hr [L/s].

h. Absorber/condenser flow rate,

gpm or lb/hr [L/sj.

i. Heat Energy Input from one of

the following:

1. Steam consumption, lb/hr

[kg/si. Steam supply

pressure, psig [kPa].

Steam supply temperature, F

[°CJ. Steam condensate

temperature, F [°CJ.

2. Hot water flow rate, gpm

[Us]. Hot water supply

temperature, F [°C]. Hot

water leaving temperature, F

[°C].

3. Gas consumption, ft3/hr

[M3/hrj. Higher gas heating

value (HHV), BtuIFt 3[J/M3].

Gas pressure entering gas

train, in. 1120 or psig [mm

AqJ.

4. Oil consumption, gph L/s.

Higher oil heating value

(HHV), Btu/gal [JIL]. Oil

classification (for example,

Class A Heavy Oil).

j. Electrical power consumption

for components, kW [kW].

k. Temperature of water entering

heating circuit, F [°C]. (Direct

fired heating units.)

Temperature of water leaving

heating circuit, F [°C]. (Directfired heating units.)

m. Flow rate of hot water, gpm,

[L/sJ. (Direct-fired heating

units.)

A6.1.2 if chilled water is used for

some incidental functional use, the

temperature and flow measurements of

chilled water must be made at points

beyond such take-offs and returns, so

that the measured rise reflects net

cooling capacity.

A6.1.3 If absorber/condenser water is

used for some incidental use, the

temperature and flow measurements of

condensing water must be made at

points ahead of such take-offs and

returns, so that the measured rise

reflects gross condensing heat rejection.

A6.1.4 if steam condensate is used for

some incidental functional use, the heat

content used must be added to the heat

input for heat balance purposes.

A6.2 Auxiliary data to be recorded. for

general information.

A6.2.1 Nameplate data, including

make and model, sufficient to

completely identify the water-chilling

package.

A6.2.2 Evaporator (cooler) water

pressure drop (inlet to outlet), psi or ft

of water [kPaj.

A6.2..3 Absorber/condenser water

pressure drop (inlet to outlet), psi or ft

of water [kPa].

A6.2.4 Heating water pressure drop

(inlet to outlet) psi or ft of water [kPa].

A6.2.5 Ambient temperature at test

site, F {°.

A6..3 Record Data

A6.3.1 Date, place and time of test.

13
ART STANDARD 560-92

A6.3.2 Name of test supervisor and

witnessing personnel.

Section A7. Test Procedure

A7.1 Preparation for Test

A7.1.1 The absorption water-chilling

package, which has been completely

installed in accordance with the

manufacturer’s instructions and is

ready for normal operation, shall be

provided with the necessary

instruments.

A7.1.2 The test shall not be started

until non-condensables have been

removed from the system.

A71.3 At the manufacturer’s option,

tubes in the absorber, condenser,

evaporator, and separate heat exchanger

(if used for heating) may be cleaned as

provided in A4.2.

A7.2 Operation and Limits

14

A7.2.1 Start the system and establish

the testing conditions in accordance

with the following tolerances and

instructions:

a. Individual readings of water

temperature leaving the

evaporator (cooler) shall not

vary from the specified values

by more than 0.5

F [0.3°C].

Individual readings entering the

absorber/condenser water circuit

shall not vary by more than 0.5 F (0.3°C). Individual readings

leaving the hot water (heating)

exchanger shall not vary by

more than 0.5

F [0.3°C]. Care

must be taken so that these

water temperatures are the

average bulk stream

temperatures.

b. The chilled water, cooling

water, and heating water flow

rates (if applicable) shall not

deviate more than

±

5 percent

from that specified.

c. The leaving chilled water.

temperature shall be decreased

by an increment calculated per

A7.3 corresponding to the

specified field fouling

allowance.

d. The entering absorber water

temperature shall be increased

by an increment calculated per

A7.3 corresponding to the

specified field fouling

allowance.

e. The leaving hot water

temperature shall be increased

by an increment calculated per

A7.3 corresponding to the

specified field fouling

allowance. (Direct-fired heating

units)

f. Steam supply pressure shall be

maintained within ±0.2 psig

[1.4 kPa] of the specffied

pressure and shall be furnished

dry or within the superheat

range specified by the chiller

manufacturer.

g. Gas heating values to be used

for testing are specified in

ANSI Z21.47 Furnaces, GasFired Central (except Direct

Vent Central Furnaces). Flue

gas back pressure shall be

maintained within range

specified by the manufacturer.

h. Hot water supply temperature to

single-stage generators shall be

maintained within

±

5

F [±

3°C] of the specified

temperature and the hot water

o

9)
ARI STANDARD 560-92

flow rate shall be maintained

within ± 5 percent of the

specified flow rate.

i. Electric motors furnished as

part of the chiller package shall

be supplied with nameplate

voltage and frequency at the

motor terminals.

j. For direct-fired absorption

chiller- heaters, the CO value in

the combustion gas analysis is

specified as less than 0.02%.

When oil is used as an energy

source, the smoke density

measured by calorimetric filter

paper, is specified as No. 3 or

below.

A7.3 Methodfor Simulating Field Fouling

Allowance at Full and Part Load

Conditions

A7.3.1 Obtain the log mean

temperature difference (LMTD) for the

cooler and/or absorber/condenser using

the following equation at the specified

field fouling allowance (ff).

Due to the complexity of analyzing the

fouling effect in the condenser and

absorber separately, the two heat

exchangers have been combined in an

approximate calculation for

convenience.

LMT.D R (Al) in (1 + R/S)

A7.32 Derivation ofLMTD:

LJYITD (ts — t9) — (t3 — t1)

in — twi

The Incremental LMTD (ILMTD) is

determined using the following

equations:

ILM’ID = ff8

(-i) (A2)

A7.3.3 The water temperature

difference TDa needed to simulate the

additional fouling, TDa can be

calculated:

TDa = - S, (A3a)

zv=se-1 (A3b)

Where:

S5, = small temperature difference as

specified

S, = small temperature difference as

tested in cleaned condition

The water temperature difference, TDa

is then added to the absorber/condenser

entering water temperature or

subtracted from the cooler leaving

water temperature to simulate the

additional fouling factor.

A7.3.4 Example-Absorber/Condenser

Fouling Inside Tubes (in U.S. Standard

(t

— — t1)

tg

t9)

+ (t1— t9)

— twi

Where:

R -

LMTJJ - ILMTD

R c ez_1

15
AM STANDARD 560-92

units only, for clarity), m6 = —

Specified field fouling allowance

if, = 0.00025 hr sq ft F/Btu

6 SP ez_1

Absorber/condenser load, q =

13,000,000 Btuh

Absorber/condenser leaving water R

temp,t 1- [ . C] LMTD-ILMTD

Specified absorber/condenser entering

water temp. t = 85F [29.4°C]

TDa=5.0 3.25

Absorber/condenser inside* tube = 1.75F

surface

*

area, A = 1500 sq ft [139.4M 2]

(Since fouling is inside tubes in this example) The entering absorber/condenser water

temperature for testing is then raised

Saturated condensing temperature 1.92 F to simulate the field fouling

allowance of 0.00025 hr sq ft FfBtu.

= 106F [41.0°C] The entering condenser water

R=t 1

S,, t, - ti 106 - 101 5F temperature will be 85 + 1.75 or 86.8

-t=101-85=16F F.

= in (1 ÷ R/S ) A7.3.5 Symbols and Subscripts. The

symbols and subscripts used in

Equations Al through A3b are as

follows:

= in 1616/5) = 11 . 15 A = Total heat transfer surface,

sq ft [m j for cooler or

absorber and condenser

ff, 1,= 0.00025 hr. sq. ft. F/Btu A = A1 for fouling inside tubes

A = A0 for fouling outside tubes

ILI4TD = ffI ..c ‘ (A2) e = Base for natural logarithm

A 1 q = Total heat rejection rate or

net refrigerant capacity of

cooler, Btuh [Wj

0. 00025 ( 13, 000, 000 R = Water temperature range = 1, 500 / absolute value (t, - t)

S, = Small temperature difference

as specified

= 2 .16 F t = Temperature, F [°C]

ff, = Specified field fouling

allowance

16.
ARI STANDARD 560-92

Subscripts:

a = additional fouling

e = entering

c cleaned

f = fouled or fouling

i =inside

o = outside

1 = leaving

s = saturated vapor

w = water

sp = specified

A7.4 Heat Balance - Substantiating Test

A7.4.1 Basic. Total Heat In-Total

Heat Out. In most cases for singleeffect absorption units, heat losses or

heat gain caused by radiation,

convection, etc., are relatively small

and may not be considered in the

overall heat balance, but may be

compensated for in the heat balance

closure allowance (see A7.4.3).

A7.4.2 For double-effect machines the

high stage generator heat loss may be

significant for an uninsulated surface.

Since this surface is normally insulated

on the job site, the heat loss due to an

uninsulated high stage generator

surface can be subtracted from the

measured value. The heat loss can be

determined by radiant heat transfer

equations or verification by tests.

A7.4.3 Omission of the small heat

losses and gains mentioned in A7.4.1

results in a heat balance equation as

follows:

HB hS’1 9VC100

DC

where:

= input from heat source

= net cooling capacity

= heat reject to

condensing circuit

Any consistent system of heat units

may be used in the above equation.

For any test of a liquid cooled chiller

to be acceptable, the heat balance

(percent) shall be within the allowable

tolerance calculated per 5.5.1 for the

applicable conditions.

ev

q

17
ARI STANDARD 560-92

APPENDIX B

DERIVATION OF INTEGRATED

PART LOAD VALUES (IPLY AN]) APLV)

Section Bi. Purpose

B1.l Purpose. This appendL is intended to show

the derivation and an example of the calculation of

the Integrated Part Load Value (IPLV) or Application

Part Load Value (APLV).

Section B2. Scope

B2.l Scope. This appendix is for equipment covered

by this standard. The basic equations and procedures

are intended to provide a consistent procedure for

calculating a single number part load performance

number for water chilling products.

The basic equations (la) and (ib) as shown in section

B3.1 were developed based on a typical office

building located in Atlanta. The weather data used

for this building was obtained from ASHRAE weather

data for the city of Atlanta. A typical office building

profile was assumed with 2125 hours of mechanical

cooling per year, which was determined based on

operation from 7 a.m. to 6 p.m. 5 days per week, and

from 7 a.m. to 1 p.m. on Saturdays. The building

was equipped with an air side economizer. A single

chiller was used for this building and was sized to be

at full capacity at the design full load conditions. The

design conditions for the building are;

Summer Design Dry Bulb Temperature 94 F

Summer Design Wet Bulb Temperature 74 F

Zero Load Dry Bulb Temperature 35 F

The building load was assumed to vaiy linearly with

the ambient temperature.

The details for the building are summarized in Figures

Bi to BA and in Table Bi.

It should be stressed that the equation derived from

the above data is intended to be a typical building

model, but because of wide variations actual buildings

we strong recommend that actual energy analysis be

used to determine the part load performance and

energy use for the chiller and building. The

following are some items that can affect the chiller

operation at part load;

• Ambient Temperature Profile

• Building Load Proffle

• Water Temperature Setpoints

• Cooling Tower Size and Control

• Number of Chillers

• Control of chillers

For example, the four IPLV weighing factors for the

same building in Atlanta with two chillers vs the one

chiller would be:

CHILLER WEIGHING FACTOR

LOAD 1 CHILLER 2 CHILLERS

100% 0.17 0.29

75% 0.39 0.50

50% 0.33 0.21

25% 0.11 0.0

Section B3. Equation and Definition of Terms

B3.1 General Equation The following equation

should be used when the efficiency is expressed in

capacity divided by unit input power. An efficiency

expressed as COP should use this equation.

LPLV

or = O.17A + O.39B + O.33C + 0.11D (1)

APLV

where: A = COP at 100% capacity

B = COP at 75% capacity

C = COP at 50% capacity

D = COP at 25% capacity

The IPLV and APLV rating requires that the unit

efficiency be determined at 100%, 75%, 50% and

18
AR! STANDARD 560-92

25% at the conditions as specified in Table Bi. If the CHILLER PERFORMANCE DATA

unit cannot be operated at the 25% capacity point, the

25% point should be determined with the entering % LOAD CAPACiTY INPUT

absorber/condenser entering water (liquid) fluid (Tons) (MBtuh)

temperature corresponding to the 25% capacity

conditions. The efficiency should be calculated by 100% 400 685

using the measured power at these conditions and 75% 300 600

25% of the full load capacity. 50% 200 400

33%* 132 330

133.2 Equation Constants The constants 0.17, 0.39, * Minimum possible unit capacity

0.33, and 0.25 are based on the typical office building

in Atlanta. To reduce the number of machine data Using the above data the part load kw/ton values can

points the ASNRAE based bin data was reduced to 4 be calculated.

bins as shown below;

POINT LOAD CAP INPUT COP

BIN LOAD RANGE (TONS) (MBtuh)

1 100%-75% A 100% 400 685 0.70

2 75%-50% B 75% 300 600 0.60

3 50%-25% C 50% 200 400 0.50

4 25%-0% D 25% 100 330 0.40

Using the ASHRAE data for mechanical cooling JPLV = 0.17 x 0.70 + 0.39 x 0.60 + 0.33 x 0.50

hours of operation and the average chiller + 0.11 x 0.40 = 0.59 COP

performance for the load bin the following equation

can be used to calculate a weighted part load

performance rating.

LPLV A B B C or = O.3421x + + 0.431tx • +

A.PLV 2 2

+ D) + 0.OOx(D)

The above equation can be siinplilied by eliminating

the division by 2 which results in the following

equation;

LPLV

or = 0.17A + 0.39.8 + 0.33 C + 0.11D (1)

APLV

B3.3 Sample Calculation The following is an

example of a kw/ton IPLV based calculation;

19
ARI STANDARD 560-92

20

ATLANTA ASHRAE WEATHER DATA BIN HOURS

FIGURE Bi

U,

0

=

z

1,400

TOTAL HOURS — 8760 HRS

1,201

1,200 1

986]

846

800 709

666 —

608

600 1

400

305

200 .1.3.5.]

oiI

0 - - - -

II a a e a e a a e a a a •

• - Cd Cl in in a a i— a a a • I I I I I I I I I I I

o in 0 10 0 10 0 10 0 10 0 10 0 10 0 10 0 ,.- (14 (14 t q io II) in€D - a a a

OUTSIDE AIR TEMPERATURE BIN (F)

811
____________________________________

ART STANDARD 560-92

ATLANTA OFFICE BUILDING COOLING OPERATING HOURS

400

00

U,

2

9 200

100

FIGURE 82

QJTSIOE AIR TBdPERATUR BIN ()

0 hEQIAN I CAL CL I oiz ctOLIG

0 , 1• ci ci ci ci r. ci ci ci (•1 c,I 1• 1

C., Ui Ifl W Ia ci ci ci

21
ARI STANDARD 560-92

______________

ATLANTA OFFICE BUILDING COOLING LOAD PROFILE

FIGURE 63

120.0

100.0

eo .0

‘-I

60.0

40.0

20.0

MECI-ANICAL COOL FG COOLING

0.0 m ‘ UI UI 1- Ui UI Ci 1 UI 1

cJ c..I Ii O Ifl CD CD I 1 Ci Ci Ci

I I I I I I I I I I I I I I I I Ifl D U C In C In C Wi C Ifl C In C — (V (V fl Ci 1 1 In In CU ID ? I CD CD UI

OUTSIDE AIR T9.4PERATUR 61N CP)

22
ART STANDARD 560-92

4

I

IPLV BIN MECHANICAL COOLING HOURS

FIGURE 84

TOTAL OPERATING HOURS = 2125 HRS

1,200.0

43.1%

1,000.0 916.0

800.0

600.0 22% -

400.0

200.0

0.0

0-25%

OUTSIDE AIR TEMPERATURE BIN (9

25-50% 50-75% 75-100%

23
ARI STANDARD 560-92

TABLE Bi. ATLANTA OFFICE BUILDING SUMMARY

OUTSIDE AVG DB. TOTAL BiN TOTAL COOLING 0-25% BIN 25-50% BIN 50-75% BIN 75-100% BiN

TEMP. HOURS COOLING LOAD (%) HOURS HOURS HOURS HOURS

(F) (F) HOURS

100-105 102.5 0 0 100.00 0 0 0 0

95-99 97.5 0 0 100.00 0 0 0 0

90-94 92.5 156 103 M 97.56 0 0 0 103

85-89 87.5 367 254 M 88.96 0 0 0 254

80-84 82.5 611 370 M 80.51 0 0 0 370

75-79 77.5 838 353 M 72.03 0 0 353 0

70-74 72.5 1201 301 M 63.56 0 0 301 0

65-69 67.5 986 262 M 55.08 0 0 262 0

60-64 62.5 846 248 M 46.61 0 248 0 0

55-59 57.5 773 234 M 38.14 0 234 0 0

50-54 52.5 709 213 E 29.66 0 0 0 0

45-49 47.5 666 200 E 21.19 0 0 0 0

40-44 42.5 608 158 E 12.71 0 0 0 0

35-39 37.5 471 108 E 4.24 0 0 0 0

30-34 32.5 305 0 0 0 0 0 0

25-29 27.5 135 0 0 0 0 0 0

20-24 22.5 53 0 0 0 0 0 0

15-19 17.5 35 0 0 0 0 0 0

10-14 12.5 0 0 0 0 0 0 0

TOTAL 8760 2125M 0 482 M 916 M 727 M

% TOTAL 0 22.68% 43.11% 34.21%

E - Economizer operation

M - Mechanical refrigeration cooling

24