# IMA**C TEA M 2 A**  **PPENDIX I** 

**Procedure for measuring system COP [Coeffi cient of Performance] of a mobile air condtioning**  **system on a test bench DRAFT** 

SAE Technical Standards Board Rules provide that: “This report is published by SAE to advance the state of technical and engi neering sciences. The use of this report is ent irely voluntary, and its applicability and suitability for any particular use, including any patent infringement arising therefrom, is the sole responsibility of the user.” SAE reviews each technical report at least every five years at which time it may be reaffirmed, revised, or cancelled. SAE invites your written comments and suggestions. Copyright © 2003 SAE International All rights reserved. No part of this publication may b e reproduced, stored in a retrieval system or transmitted, in any form or by an y means, electronic, mechanical, photocopying, recording, or otherwise, without the prior written permission of SAE. **TO PLACE A DOCUMENT ORDER: Tel: 877**  **- 606**  **- 7323 (inside USA and Canada)**  **Tel: 724 -**  **776 -** **4970 (outside USA) Fax: 724**  **- 776**  **- 0790**  **Email: custsvc@sae.org SAE WEB ADDRESS:**  **http://www.sae.org PropDft**  **J276 5** 

**1.0 Purpose**  **1.1** This Standard provides a method of testing the capacity (performance) and efficiency (COP) of mobile air conditioning refrigerant systems under steady state conditions. **1.2** The procedure proposed is designed to give maximum repeatability and minimu m error in determining cooling capacity (Q) and efficiency

(COP

– Coefficient of Performance) of the refrigeration system of the mobile air conditioner. For that reason a “breadboard” ty pe facility is proposed in which components are assembled into a syst em and exposed to operating conditions in individual, separately controlled chambers. The facility should allow for three methods to determine system performance: refrigerant side, airside, and calorimetric chambers. Each side y ields its own energy balan ce calculation to find the capacity of the system. W ith the three methods used, instead of two as ty pically required, redundancy

will be m aintained even when the evaporator refrigerant exit is two phase, or operation is unstable. In this case only the ai rside balance is available. The design should be made so that two independent methods could provide agreement of less than within 6.0% between two independent balances. **2.0 Scope**  **2.1** This Standard applies to motor driven mobile air conditioning systems consisti ng of one in
- car air coil (evaporator), a compressor, an expansion device, and one under
- hood air coil (condenser). **2.1.1** This standard can also be used for measuring systems that use electrically driven compressor if measurement of input power to compressor i s carefully considered. **2.1.2** This standard can also be used for measuring systems that include the entire air handling system if air side pressure drop for the entire vehicle system is carefully considered. **2.1.3** This standard can also be used for measuring systems t hat include the entire front end cooling module if air side pressure drop for the entire vehicle system is carefully considered. **2.1.4** This standard can also be used for measuring systems that include a secondary cooling loop if the power to drive the pumps in t his system is carefully considered. **2.2** This Standard specifies procedures, apparatus, and instrumentation that will produce accurate steady

state capacity and efficiency data for refrigerant components

.**SA E J276**  **5 Issued Proposed Draft 23MA**  **R2006**

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- **2.3** This Standard does not: **2.3.1** Specify

tests for dual evaporato r systems, **2.3.2** Specify

transient test methods, **2.3.3** Make recommendations for safety **2.3.4** Specify

tests for production, specification compliance, or field testing of mobile air conditioning systems. **3.0 Definitions**  **3.1 air, standard:**  dry air having a m ass density of 1.204 kg/ m 3 (0.075 lb/ft 3 ). **3.2 apparatus:**  as used in this standard, this term refers exclusively to test room facilities and instrumentation. **3.3 capacity, total cooling:**  the rate, expressed in watts (Btu/hr), at which the equipment removes heat from the air passing through it under specified conditions of operation. **3.4 COP, coefficient of performance:**  a measure of the efficiency of an air conditioning system, defined as the average heat removed through the evaporator divided by the average work input to the compressor **3.4.1** A djustments to this calculation may be necessary

for electrically

driven compressors, in case the air handling system is used, in the case of front end cooling module is used, and for secondary cooling loop systems. **3.5 equipment:**  as used in this standard, this term refers exclusively to the mobile air conditioning equipm ent to be tested. **3.6 pressure, standard barometric:**  101.325 kPa (14.696 psi). **3.7 refrigerant, :**  a refrigerant that changes from the liquid to the vapor state in the process of absorbing heat. **3.8 shall**  or **shall not** is used to indicate a provision that is mandatory if compliance with the standard is claimed. **3.9 should, recommended**  or **it is recommended** is used to indicate provisions which are not mandatory

but which are desirable as good practice. **4.0 Instrumenta**  **tion 4.1**  **Temperature Measuring Instruments 4.1.1**  All tem perature measurements (with the exception of dew point temperature) shall be made in accordance with ANSI/ASHRAE Standard 41.1
- 1986 (RA 2001). 1 **4.1.2** If used in determining the water vapor content of the air, dew poi nt hygrometers shall be applied as specified in ANSI/ASHRAE Standard 41.6
- 1994 (RA 2001) 2 and shall be accurate to within ±0.2 °C (0.4 °F). **4.1.3** Inlet air temperature measurements are to be taken upstream of static pressure taps on the inlet duct (if installe d). Outlet air temperature measurements shall be taken downstream of the static pressure taps on the outlet. **4.2 Pressure M**  **easuring Instruments SA**  **E J276 5**  **Issued Proposed Draft 23MA R2006** 

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- **4.2.1** Pressure measurements shall be made with any device meeting the requirements of ASHRAE 41.3
- 1989. 3 **4.2.2** The accuracy

of pressure measuring instruments shall permit measurement to within ±2.5% of the reading. **4.3 Ai**  **r Differential Pressure and A irflow Measurements**  **4 4.3.1**  The static pressure difference across nozzles and velocity pressures at nozzle throats shall be measured with mano me ters or electronic pressure transducers that have been calibrated against a pressure standard to within ±1.0% of the reading. The resolution of the device shall be equal to or less than 2.0% of the reading. **4.3.2** Areas of nozzles shall be determined by measu ring their diameters to within ±0.20% in four places approximately equally spaced around the nozzle in each of two planes through the nozzle throat, one at the outlet and the other in the straight section near the radius. **4.4 Electrical Instruments**  **4.4.1** Electrical me asurements shall be made with indicating or integrating instruments. **4.4.2** Instruments used for measuring the electrical power input to fan motors or other equipm ent accessories shall be accurate to within ±2.0% of the reading. **4.4.3** Voltages shall be measured at the equipm ent terminals. Instruments used for me asuring voltage shall be accurate to within ±1.0% of the reading. **4.5 Refrigerant Flow Measurement**  **4.5.1** Ref rigerant flow shall be measured with an integrating flow measuring system that is accurate to within ±1.0% of the reading **4.6 Condensate**  **Quantity Me**  **asurement 4.6.1**  Condensate collection rates shall be determined using a liquid quantity meter that is accurate to within ±1.0% of the reading. **4.7 Speed Measuring Instruments**  **4.7.1** Speed m easurements shall be made with a revolution counter, tachometer, stroboscope, or oscilloscope that is accurate to within ±1.0% of the reading. **4.8 Time and Mass Measurements**  **4.8.1** Time interval measurements shall be made with an instrument that is accurate to within ±0.2% of reading. **4.8.2** Mass Measurement shall be made with an apparatus that is accurate to within ±1.0% of reading. **4.9 Torque Measurements**  **4.9.1** Torque measurements shall be made with an instrument that is accurate to within ±2.0% of reading. **4.10** R efrigerant mass composition measurements for refrigerant mi xtu res shall be made using an instrument that is in accordance with ARI Standard 700
- 2004. 5**SA E J276**  **5 Issued Proposed Draft 23MA**  **R2006**

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- **5.0 Test Facility and**  **Me asuring A**  **pparatus 5.1**  **Test Facility** (Figure 1) Recommended configurations for the test facility are provided below. In all cases, suitable means fo r determining the dry
- bulb tem perature and water vapor content of the air entering and leaving the heat exchangers shall be provided.

**B** - Blower, **CP** - Compressor, **CC** - Cooling Coil, **CH** - Glycol Chiller, **Cond** -Condenser, **Dp** - Differential Pressure Transducer, **Ev ap**  - Evaporator, **FS** - Flow Straightener, **H** - Heater, **Hu** - Humidifier, **mg** - Glycol Mass Flow Meter, **mr** - Refrigerant mass Flow Meter, **Mtr** - Motor, **N** - Nozzle, **P** -Pres sur e Transducer, **RH** - Relative Humidity Probe, **Sc** - Condensate Scale, **Sp** - Speed Controller and Tachometer, **T** - Thermocouple, **TC** - Temperature Controller, **TG** - Thermocouple Grid, **Tor**- Torque Transducer, **W**- Watt Transducer, **TXV** - Thermal Expansion Valve Ind ic es : **a** - air, **c**-condenser, **cp** - comp ressor, **e** -evaporator, **g** - glycol, **I** - inlet, **n** -no zzle, **o** -outlet, **r** - refrigerant, **Evaporat or**  **Chamber Condenser**  **Chamber Tgo** 

**Sc Tgi**  **Gly col**  **Chiller**

**m r**  **R&D Tx**  **ri Te**  **ro CP** 

**Tc pr**  **i, Pcpri T**  **c p**  **r o**  **, P**  **c p**  **r o**  **M t**  **r**

**Tor T** **X V** 

**TC**

**W H**  **B Te**  **ai TG**

**Hu N** 

**Ten 1 Tdpen**  **Tdpei RH** 

**Peri** Dper Sp

**FS**

**Teao TG**

**Steam M**  **mg**

**TH Co**  **mpr essor**  **Ch amber** 

**B H**  **CC N**  **T c**  **n 1** 

**TC Tc**  **ai TG**

**Sp**

**Dpcn**

**W Tcro,**  **Pcro Tcri**  Dpcr **Tcao TG M**  **T**

**Te n 2** 

**Dpea Dpen**  **Dpca T**  **c n**  **2**

**DPc d**  **Co nd**  **. Evap** 

**Figure 1**  **Sample Test Facility 5.2**  **Test Room Requirements 5.2.1**  Ty pically , two test rooms are required; an in car room and an under
- hood room. If desired, a third room may be used for the compressor to simulate under
- hood conditions. **5.2.2** An in car condition test room is required. This may be any room or space in which the desired test conditions can be main tained within the tolerances given in Table 1.**SA E J276**  **5 Issued Proposed Draft 23MA**  **R2006**

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- **5.2.3** An under
- hood test room is required. This may be any room or space in which the desired test conditions can be maintained within the tolerances given in Table 1. A condenser wind tunnel may be substituted for the under
- hood test room provided it is capable of maintaining the conditions given in Table 1.

**Table 1**  **Permissible Variations in Test Conditions** Test Operating Tolerance (1) Test Condition Tolerance (2) Evaporator dry
- bulb t emperature (°C) 1.0 0.3 Evaporator wet
- bulb temperature (C) 0.5
-- Condenser dry
- bulb temperature (°C) 1.0 0.3 Condenser wet
- bulb temperature (°C) 0.5
-- Saturated refrigerant temperature (°C) 1.7 0.3 Liquid temperature if not otherwise specified ( °C) 0.3 0.1 External resistance to airflow (Pa) 12.5
-- Electrical voltage (% of reading) 2.0
-- Condensate flow (% of reading) 2.0
-- Nozzle pressure drop (% of reading) 2.0
-- High Side Refrigerant Pressure [kPa] Low side Refrigerant Pressure [k Pa] Refrigerant Flow [g/s] Refrigerant Differential Pressure [kPa] (1) Test Operating Tolerance is the maximum permissible range of any measurement. (2) Test Condition Tolerance is the maximum permissible variation of the average value of the meas urement from the specified test condition. **5.3 Wind tunnels for heat exchangers**  **5.3.1** To produce repeatable and comparable results, it is recommended to control the inlet air tem perature and velocity profile across the face of the test heat exchangers . **5.3.2** Below is an example of one setup that has been used to accomplish this end. **5.3.2.1** Each test heat exchanger shall be mounted in a wind tunnel inside the ir respective test room. The wind tunnel may be constructed from any suitable duct material. The illustration of a duct s ections for the test heat exchanger in a wind tunnel are shown in Figure 2.**SA E J276**  **5 Issued Proposed Draft 23MA**  **R2006**

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- **5.3.2.2** Air enters over the flow stra ight e ner (1) and inlet thermocouple grid (2) to the test heat exchanger (evaporator , condenser , or gas cooler). At the exit of the test heat ex changer is the outlet thermocouple grid (3) before the flow measuring devices

– nozzles (4). After the nozzles, average air stream temperature is measured by a thermocouple or other appropriate thermometer (5). Reconditioning of the air (cooling or heating) is done in the conditioning test facility heat exchanger (6). For control purposes, an electrical heater is rec om me nded. The test facility Blower (7) provides air circulation for the test heat exchanger

.

**Figure 2**  **Possible A ir Loop**  **[re -**  **draw to show straightener and identify necessary insulation] 5.4**  Airflow Measuring Apparatus **5.4.1** A suitable means of measuring heat exchanger air flow shall be provided. One such method is given in ANSI/ASHRAE Standard 41.2
- 1987 (RA 92). 6 As shown in Figure 4, the nozzle airflow m easuring apparatus consists of a receiving chamber and a discharge chamber separated by a partition in which one or more nozzles are located. **5.4.2** The nozzles used to measure air flow shall comply with ANS I/ASHRAE Standard 41.2
- 1987 (RA 92) 5 or suitable alternative (ASME, ISO, JIS, etc.). The discharge coefficient shall be calculated and evaluated as given in ANSI/ASHRAE Standard 51
- 1999 7 or ASME Fluid Meters. **4**
**Ad d references to figure 3? Do we need A** **SHR AE**  **approval to use ?** **SA E J276**  **5 Issued Proposed Draft 23MA**  **R2006**

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- **Figure 3**  **Nozzle A irflow Measuring A**  **pparatus (A NSI/A** **SHRA E Standard**  **37 -**  **2005 8**  **)**

**Figure 4**  **Flow Nozzle Construction (A NSI/A** **SHRA E**  **Standard 37**  **- 2005**  **)**

**5.4.3** The velocity

profile when measured at no t less than nine (9) grid points should be within ± 10% . Additional m eans shall be used when needed to improve uniformity of the air velocity

profile. Consult ANSI/ASHRAE Standard 41.2
- 1987 (RA 92) 6 for methods of flow straightening to achieve the desired velocity profile. **5.4.4** Temperature measurements shall be made at not less than the same nine (9) locations as in 5.4.3. at the center of equal segments of cross
- sectional area throughout the duct. Inlet air temperature should be uniform within ± 0.5 °C. Consul t ANSI/ASHRAE Standard 41.1
- 1986 (RA 2001) 1 for methods of mixing the air stream to achieve the desired uniformity of temperature.**SA E J276**  **5 Issued Proposed Draft 23MA**  **R2006**

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- **5.5** Refrigerant loop (Figure 5) **5.5.1** The refrigerant loop should mimic as much as possible conditions encountered in the reference vehicle environm ent. The components used in the vehicle should be used in the test loop if possible. Alteration of the piping (lines, hoses, and fittings) from the real application should be fully documented. **5.5.1.1** Suction line pressure drop should be +/
- 10 % of the reference vehicle application **5.5.1.2** If a Internal Heat Exchanger [IHX] or suction line heat exchanger is used in the system, it should be located in the same ambient environment as the compressor. **5.5.1.3** Relative height of the components should be located with in +/
- 25 mm of the reference vehicle system. If no reference vehicle is defined, the bottom of compressor should be located at bottom of condenser and bottom of evaporator shall be located at top of condenser. [Figure 5a] **5.5.1.4** System refrigerant charge amount should not be greater than 125 % of the reference vehicle system. **5.5.1.5** Oil amount should be revised based on charge amount to approximate the same ratio of refrigerant to oil ratio as the reference vehicle system. **5.5.1.6** Oil in circulation shall meet the compressor ma nufacturer’s requirements. **5.5.2** Instrumentation shall be installed so as to minimize their effect on system operation or performance.
Add nozzle tem peratures, additional instrumentation, show 2 nd view that illustrates height of components

TM

Air in Air in

SG Mr MF IRD Cond. Evap. Evaporator Chamber Wall Condenser Chamber Wall

Dpen Comp. Compressor Chamber

Motor Tor

Tcao

Tcai Dpcn Teai

Teao Sp

Pcpro Pcpri Tcpri Tcpro Tcri Tcro

Pcro

TG

TG TG

TG

DPcr Tero Pero

DPer

Ten 1 NZ

Ten 2 NZ Tcn1 Tcn2

Tcph
Teri

EXV

Pxri Txri **Figure 5**  **Ty pical Refrigerant Loop** **SA E J276**  **5 Issued Proposed Draft 23MA**  **R2006**

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- **Figure 5a Illustration of component heights.**
**5.5.3** Compressor Test Stand and Chamber **5.5.3.1** The compressor is placed inside a third chamber that provides and controls specified conditions. The temperature should be ma intained within  2 o C. **5.5.3.2** The torque meter should be located between the compressor and the clutch in order to measure compressor power at the shaft.



## Dr ive Mo to r Be lt Id le r Pu lle y Com pr es so r Cl utc h To rq ue

Me te r A/ C

Com pr es so r Sh af t Co up le r

**Figure 5b Torque meter location** **SA E J276**  **5 Issued Proposed Draft 23MA**  **R2006**

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- **6.0 Test Conditions**  **6.1** T o allow for variation of spec ified compressor speeds for different drive ratios or compressor ty pes RPM of compressor should be adjusted as necessary based to match the system capacity

at L35 test conditions

. **6.2** The test matrix is shown in Table 2. The conditions cover a significant ran ge of ty pical vehicle air conditioning operation. **6.3** Performance can be determined with the system operating at full capacity or at a reduced capacity to lim it evaporator air outlet temperature (measured at the outlet of the airflow nozzles). Lim iting evaporator air outlet temperature allows comparisons at approximately equal capacity , allows sim ulation of smart variable temperature control, and can provide evaporator icing prevention. Depending on the compressor, capacity can be controlled by vary ing displa cement, cycling rates/temperature swings, etc. Precisely achieving a target temperature can sometimes be difficult due to resolution in the controls. Specification of the target temperature should be consistent across systems to be compared.**SA E J276**  **5 Issued Proposed Draft 23MA**  **R2006**

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- **Table 2**  **Test Matrix** Ambient temp. [ o C] Comp

speed [rpm] Condenser Conditions Evaporator Conditions Dew point [°C] Inlet air temp [ o C] Face velocity

[m/s] Inlet air temp

[ o C] Face velocity

[m/s] 45 900 60 1.5 35 2.0 12
“ 900 45 1.5 “ 2. 0 “
“ 1500 “ 3.0 “ 2.5 “
“ 2500 “ 4.5 “ 2.5 “
“ 4000 “ 4.5 “ 2.5 “ 35 900 50 1.5 35 2.0 19.4
“ 900 35 1.5 “ 2.0 “
“ 1500 “ 3.0 “ 2.5 “
“ 2500 “ 4.5 “ 2.5 “
“ 4000 “ 4.5 “ 2.5 “ 35 900 35 1.5 35 1.5 19.4
“ 1500 “ 3.0 “ 1.0 “
“ 2500 “ 4.5 “ 1.0 “
“ 4000 “ 4.5 “ 1.0 “ 25 900 40 1.5 25 1.5 21.3
“ 900 25 1.5 “ 1.5 “
“ 1500 “ 3.0 “ 1.0 “
“ 2500 “ 4.5 “ 1.0 “
“ 4000 “ 4.5 “ 1.0 “ 25 900 40 1.5 25 1.5 13.9
“ 900 25 1.5 “ 1.5 “
“ 1500 “ 3.0 “ 1.0 “
“ 2500 “ 4.5 “ 1.0 “
“ 4000 “ 4.5 “ 1.0 “ 25 900 25 1.5 25 1.0 13.9
“ 1500 “ 3.0 “ 0.7 “
“ 2500 “ 4.5 “ 0.7 “
“ 4000 “ 4.5 “ 0.7 “ 15 900 30 1.5 15 1.0 11.6
“ 900 15 1.5 “ 1.0 “
“ 1500 “ 3.0 “ 0.7 “
“ 2500 “ 4.5 “ 0.7 “
“ 4000 “ 4.5 “ 0.7 “**SA E J276**  **5 Issued Proposed Draft 23MA**  **R2006**

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- **6.4** System setup tests **6.4.1** A ty pical Refrigerant charge determination procedure is shown below. Other procedures may

be used based on user preferences. **6.4.1.1** A charge determination shall be performed at the following conditions: **6.4.1.1.1** T he charging condition should be: compressor speed 2000 rpm, full displacement, **6.4.1.1.2** C om pre ssor chamber temperature 70oC; **6.4.1.1.3** A ir temperature inlet to the gas cooler/condenser 40oC, **6.4.1.1.4** A ir velocity through the gas cooler/condenser 3.7 m/s **6.4.1.1.5** air temperature inlet to evaporator 40oC, **6.4.1.1.6** A ir velocity through the evaporator 2.5 m/s **6.4.1.1.7** R elative hum idity at evapo rator inlet of 40%. **6.4.1.1.8** Other conditions in adddition to this are permited. **6.4.1.1.9** Compressor RPM may be adjusted based on equalizing capacity

. **6.4.1.2** The system shall be operated for a minimum of ten (10) minutes at the above conditions before starting the charge determ ination. This is to insure stable operation during the charge determination. **6.4.1.3** Select the initial am ount of refrigerant based on system size. In no case should be system be operated with less than 1/2 the expected total charge. **6.4.1.4** After allowing system to stabilize, record data for ten (10 ) minutes. Average the data to obtain average readings. **6.4.1.5** Add refrigerant in increments of no more than 50 g. **6.4.1.6** The system shall be allowed to stabilize for a minimum of ten (10) mi nutes after adding charge and before re cording data. **6.4.1.7** Figure 8 shows a ty pical charge determination result for a non
- subcooled condenser R134a system. The recommended criteria for R134a is : [other fluids may

have different criteria] **6.4.1.7.1** M inim um of 5 K subcool **6.4.1.7.2** Compressor out pressure not to exce ed 1800 kPa**SA E J276**  **5 Issued Proposed Draft 23MA**  **R2006**

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- **SAE R134a charge determination test Note:**  evaporator exit DTsuperheat kept = 6~8 K

0 5 10 15 20 25 30 35 40

400 500 600 700 800 900 1000 1100 1200 1300 **Charge [g] C** **O P** **[ -** **] /** **Q e** **[ k** **W ]** **/ D** **T [** **K ]** **/ T** **[ C** **]**

0 500 1000 1500 2000**P r** **c p** **o [** **k P** **a ]** **/ P** **r c** **p i** **[ k** **P a** **]**

COP_av g Q_av g DTsubcool Teao_at_nozzle DTsuperheat Proper Charge 1125g Prcpo Prcpi

**Figure 6**  **Sample Charge Determination Legend:**  COP_avg

– Coefficient Of Performance (average), Q_avg

– Refrigeration capacity at evaporator (average), Teao
- Temperature of evaporator air out measured at nozzle, DTsubc ool

– Condenser outlet subcool, DTsuperheat

– Evaporator outlet superheat, Prcpo

– Compressor outlet (discharge) pressure, Prcpi

– Compressor inlet (suction) pressure

**6.4.2** Oil in circulation rat e **6.4.2.1** Using test conditions as specified in Table 2 at 45oC and 900 RPM and 45oC and 2500 RPM , a sample of the circulating refrigerant and oil mi xture should be taken from the equipment and the percentage of oil me asured in accordance with ANSI/ASHRAE Standard 41.4
- 1996. 9 [Except sample amount is 30 grams.] The total indica ted flow rate should then be corrected for the amount of circulating oil. Adjust oil amount to obtain compressor supplier recommended oil in circulation

. [Other me thods are acceptable based on user preferences] **6.4.3** Temperature and air velocity uniformity **6.4.3.1** To provide equal conditions for all systems to be tested and insure reproducibility

of the test results, u n iformity of air velocity

and temperature at the inlet to the heat exchangers must be verified prior to starting the refrigeration system performance tes t. Each test should be performed for both heat exchangers (condenser/gas cooler and evaporator) and over a relevant range of air velocities and inlet air temperatures.**SA E J276**  **5 Issued Proposed Draft 23MA**  **R2006**

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- **6.4.4** Air side pressure drop [dry ] **6.4.4.1** At room temperature, change airflow rate to cover the ra nge of operation in Table 2 and record the pressure drop from inlet to outlet of each heat exchanger with the compressor turned off. **6.4.5** Suction line pressure drop **6.4.5.1** Check refrigerant pressure drop from evaporator out to compressor inlet and verify

that the requ irements in 5.5.1.1 are met. **6.4.6** Refrigerant control strategies **6.4.6.1** Verify

that all control strategies that would normally be used in the refrigerant system are duplicated per the reference vehicle that is being simulated. [For example: superheat control, compres sor out pressure control] **6.5** Operating procedure **6.5.1** The facility

operating procedures for the steady state tests procedure elements are: **6.5.1.1** Pre
- set test condition parameters. **6.5.1.2** Wa rm up or cool down the test chambers and adjust the parameters as needed until a stable condition is reached

. **6.5.2** Establish and maintain stable conditions for at least twenty [20] mi nutes prior to taking data. Steady

state conditions are characterized by no more than +/
- 0. 2 o C variation of heat exchanger inlet air and +/
- 0.1 o C for dew point te mp eratures recorded at the beginning and after ten (10) minutes. Trend in temperatures shall not be downward or upward by greater than 0.2oC. **6.5.3** Once stable conditions are achieved, d ata shall be collected for a minimum of 10 additional mi nutes with a m ini mu m frequency of 0.1 Hz

. [In the case of cycling system operation, measurements should be taken with a minimum frequency of 10Hz for compressor torque and speed. Torque will be time averaged.] **7.0 Calculations**  **7.1** Evaporator Capacity shall be me asured using three independent m ethods [See Figure 7] **7.1.1** Air Capacity

= dry air mass flow rate * air enthalpy difference

– condensate enthalpy (small) : Additional factors should be added to compensate for any heat loss in the duct from the heat exchanger outlet to the nozzle outlet. Q i n d o o r a i r = Ma i n d o o r , d ry · ( h e a i

– h e a n ) + Q l e a k d u ct – Ma i n d o o r , d ry · ( W e i

– W e n ) · **h** ( ' S te a m N B S ' , T = T e n , x = 0 ) **7.1.2** Refrigerant capacity shall be calculated using the following: Refrigerant Capacity

= refrigerant mass flow rate * refrigerant enthalpy difference

Q i n d o o r re f = M r · ( 1

– X o i l ) · h e ro – h e r i

1 0 0 0 + M r · X o i l 1 0 0 0 · 2

. 0 4 9 9 · ( T e ro – T e r i s a t ) + 0

. 0 0 2 2 6 1 2 · ( T e ro 2

– T e r i s a t 2 )**SA E J276**  **5 Issued Proposed Draft 23MA**  **R2006**

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- **7.1.3** Chamber capacity = electric heat + steam supplied energy +/
- heat gain/loss through the chamber walls (small). 

### Q h x 

### : = Q s te a m 

### + Q s te a m 2 

### + W 1 0 0 0 – Q t ra n s

**Figure 7**  **Capacity Measurement Schematic for all three methods**  **7.1.4** Properties of refrigerants shall be obtained from 2001 ASHRAE Handbook
Fundamentals 1 0 or from an established refrigeran t property database. 10 **7.1.5** Air enthalpies shall be determined in accordance with ANSI/ASHRAE Standard 41.6
- 1994 (RA 2001). 2 or other established database. **7.2** Reported Capacity Calculation **7.2.1** The reported capacity is used to calculate COP. At least two of these inde pendent capacities measurements shall be within 5% and the reported capacity shall be the average of these two values. **7.3** Compressor Power Calculation **7.3.1** Compressor power is calculated as given below: 

### T 60 2 π rpm W com p 

###    **7.3.2** In the case of cycling compressors, t he a verage compressor power is calculated by integrating the power over complete cycles during the stabilized ten minute me asurement. **7.3.3** For variable compressors, the average power over the stabilized ten minute me asurement is used. **7.4** Refrigerant system Coeffic ient of Performance (COP) Calculation **7.4.1** Coefficient of performance shall be calculated as follows:



### C O P i n d o o r , a v

g 

### = Q i n d o o r a v

g 

### W c o m p**SA E J276**  **5 Issued Proposed Draft 23MA**  **R2006**

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- **7.4.2** Condenser/gas cooler fan and evaporator blower power is not included in th is COP calculation. This calculation shall be modified if configurations described in paragraph 2.1 are being evaluated. **8.0 Data to be Recorded**  **8.1** System description **8.1.1** The system and test conditions should be described, as far as possible, specify ing: **8.1.1.1** Size and weight of com ponents. **8.1.1.2** Air pressure drop through the evaporator and condenser/gas coo ler. **8.1.1.3** Uniformity

of airflow velocity

and inlet air temperature to the evaporator and condenser. **8.1.1.4** Line lengths (should be similar in length and diameters to real system). **8.1.1.5** Charge determination criteria. **8.1.1.6** Oil ty pe, charge, and concentration in circulation. **8.1.1.7** Expan sion device. **8.1.2** Control of evaporator air outlet temperature should be described. Some systems use variable displacement compressors whose capacity is controlled to maintain the desired air outlet temperature (if the system could reach that temperature), som e are clutch cycling, some have other ways of reducing capacity . All systems ty pically exhibit some oscillation at very low loads and these should be reported.**SA E J276**  **5 Issued Proposed Draft 23MA**  **R2006**

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- **9.0 Symbols used in Equations**  A nozzle throat area (m 2 ) C nozzle discharge coefficient (dimension less) E i power input, evaporator side (W ) h a1 enthalpy , air entering evaporator (J/kg dry air) h a2 enthalpy , air leaving evaporator side (J/kg dry air) h r1 enthalpy , refrigerant entering evaporator (J/kg) h r2 enthalpy , refrigerant leaving evaporator (J/kg) P comp power, compressor (W ) P v pressure drop across the nozzle (Pa) q tci total cooling capacity , evaporator (W ) Q s air flow, standard air (m 3 /s) Q v airflow rate (m 3 /s) rpm revolutions per minute T torque, compressor (N
- m) v n specific volum e of the dry a ir portion of the mi xture evaluated at the dry
- bulb temperature and barometric pressure at the nozzle exit, and vapor content evaluated at the leaving conditions (m 3 /kg dry

air) v’ n specific volume of air at nozzle (m 3 /kg) v nsp specific volum e of the dry a ir portion of the mi xture evaluated at the dry
- bulb temperature at the nozzle exit and vapor content evaluated at the leaving conditions but at standard barometric pressure (m 3 /kg dry air) W n hum idity ratio at the nozzle (kg water vapor/kg dry air) w ro ma ss flow rate, refrigerant oil mixture (kg/s) x ma ss ratio, refrigerant to refrigerant oil mixture (deminsionless)  density of refrigerant (kg/m 3 )**SA E J276**  **5 Issued Proposed Draft 23MA**  **R2006**

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- **Ap pendix XXX Examples of calibration records**  1. The UA value for calorimetric chambers

. 2. Pressure calibration 3. Torque transducer calibration,... **Ap pendix FFF**  **– supporting data**  1. Uniformity

of velocity

profiles 2. Uniformity

of temperature profiles 3. Air side Pressure drops**SA E J276**  **5 Issued Proposed Draft 23MA**  **R2006**

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- **10.0 References**  **Table 3**  **List of Variable Names** AFR_scfm_indoor Total volumetric air flow rate, indoor [scfm] AFR_scfm_outdoor Total volumetric air flow rate, outdoor [scfm] COP_indoor_air Coefficient of performance based on air balance, indoor chamber COP_indoor_chamber Coefficient of performance based on chamber balance, indoor chamber COP_indoor_ref Coef ficient of performance based on refrigerant balance, indoor chamber COP_outdoor_air Coefficient of performance based on air balance, outdoor chamber COP_outdoor_chamber Coefficient of performance based on chamber balance, outdoor chamber COP_outdoor_ref Coefficient of performance based on refrigerant balance, outdoor chamber DPca Air pressure difference across gas cooler/condenser DPcd Air pressure difference between condenser air inlet and nozzle air inlet, for flow restriction simulation test DPcn Air pressure difference across condenser nozzle DPcr Refrigerant pressure drop across condenser DPea Airside pressure drop across evaporator DPen Air pressure drop across evaporator nozzle DPer Refrigerant pressure drop across evaporator DP ersl Refrigerant pressure drop across evaporator and suction line, DPersl=DPer+DPsl Dslope Slope of condensate for evaporator, condensate rate [lbm/s] Dslope2 Slope of condensed steam after entering indoor chamber [lbm/s] DT_desup_cp_out Desuperhea t compressor outlet [degC] DT_sub Subcooling condenser out [degC] DT_sup Superheat evap out [degC] DT_sup_cp_in Superheat compressor inlet [degC] ErrIndoor_air Percent difference between air and indoor chamber energy balances ErrIndoor_ref Percen t difference between refrigerant and indoor chamber energy balances ErrOutdoor_air Percent difference between air and outdoor chamber energy balances ErrOutdoor_ref Percent difference between refrigerant and outdoor chamber energy balances eta_c Isen tropic efficiency eta_v Volum etric efficiency Fc Torque of compressor [N
- m / lbf
- in] hcai Moist air enthalpy at condenser inlet hcan Moist air enthalpy at condenser nozzle hcri Refrigerant enthalpy at condenser inlet hcro Refrigerant enthalpy a t condenser outlet heai Air enthalpy at evaporator inlet heai_dry Dry air enthalpy

at evaporator inlet hean Air enthalpy at evaporator nozzle hean_dry Dry air enthalpy

at evaporator nozzle heri Refrigerant enthalpy at evaporator inlet hero Refr igerant enthalpy at evaporator outlet hvin Wa ter vapor inlet enthalpy**SA E J276**  **5 Issued Proposed Draft 23MA**  **R2006**

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- hvout Wa ter vapor nozzle enthalpy h_compin Refrigerant enthalpy at compressor inlet h_compout Refrigerant enthalpy at compressor outlet h_fg Latent heat of vaporization h_liq_ in Saturated liquid enthalpy at inlet state h_liq_out Saturated liquid enthalpy at outlet state h_vap_in Saturated vapor enthalpy at inlet state h_vap_out Saturated vapor enthalpy at outlet state Ma_indoor_dry Dry air mass flow rate across evapora tor Ma_indoor_wet Det air mass flow rate across evaporator Ma_outdoor Det air mass flow rate across condenser Ma_outdoor_dry Dry air mass flow rate across condenser Mr Refrigerant flow [g/s] Mw_kgps Condensate rate [kg/s] Mw_kgps2 Condensate ra te from steam line inside evaporator duct [kg/s] Patm Atm ospheric air pressure Pcn Pressure at condenser nozzles Pcri Refrigerant pressure at condenser inlet Pcro Refrigerant pressure at condenser out Pen Air pressure at nozzle entrance Peri Re frigerant pressure at evaporator inlet Pero Refrigerant pressure at evaporator out Prcpi Refrigerant pressure at compressor inlet Prcpo Refrigerant pressure at compressor out P_ratio Compression ratio [Prcpo/Prcpi] Qindoor_air Indoor cooling capa city based on air balance Qindoor_chamber Indoor cooling capacity based on chamber balance Qindoor_latent_cond Indoor chamber latent heat based on condensate rate calc. Qindoor_latent_psych Indoor chamber latent heat based on psychrometric calc. Qin door_ref Indoor cooling capacity based on refrigerant balance Qindoor_sensible_cond Indoor chamber sensible heat based on condensate rate calc. Qindoor_sensible_psych Indoor chamber sensible heat based on psychrometric calc. Qoutdoor_air Outdoor capa city based on air balance Qoutdoor_chamber Outdoor capacity based on chamber balance Qoutdoor_ref Outdoor capacity based on refrigerant balance Rhci Relative hum idity at condenser inlet Rhei Relative hum idity at evaporator inlet Rhen Relative hum idity after nozzle in evaporator Tcai Air inlet tem perature at condenser Tcao Air outlet temperature at condenser Tcic Temperature condenser chamber inside ceiling Tcif Temperature condenser chamber inside floor Tciw Temperature condenser chamb er inside wall Tcn Average nozzle tem perature in condenser Tcn1 Air temperature at condenser nozzle 1 Tcn2 Air temperature at condenser nozzle 2**SA E J276**  **5 Issued Proposed Draft 23MA**  **R2006**

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- Tcoc Temperature condenser chamber outside ceiling Tcof Temperature condenser chamber outside floor Tcow Temperature condenser chamber outside wall Tcpc Air temperature of compressor chamber, sometimes Tcph Tcri Refrigerant inlet temperature at condenser Tcro Refrigerant outlet temperature at condenser Tdpei Dew point tem perature at evaporator i nlet Tdpen Dew point tem perature at evaporator nozzle Teai Air temperature at evaporator inlet Teao1 Average of the first row of the matrix Teao11 Matrix indices (row, column) Teao12 Matrix indices (row, column) Teao13 Matrix indices (row, colu mn ) Teao14 Matrix indices (row, column) Teao2 Average of the second row of the matrix Teao21 Matrix indices (row, column) Teao22 Matrix indices (row, column) Teao23 Matrix indices (row, column) Teao24 Matrix indices (row, column) Teao3 Averag e of the third row of the matrix Teao31 Matrix indices (row, column) Teao32 Matrix indices (row, column) Teao33 Matrix indices (row, column) Teao34 Matrix indices (row, column) Teao4 Average of the fourth row of the matrix Teao41 Matrix indices (row, column) Teao42 Matrix indices (row, column) Teao43 Matrix indices (row, column) Teao44 Matrix indices (row, column) Teao_avg Average temperature of evaporator air out Teic Temperature evaporator chamber inside ceiling Teif Temperature ev aporator chamber inside floor Teiw Temperature evaporator chamber inside wall Ten Average nozzle tem perature Ten1 Temp of evaporator air nozzle 1 Ten2 Temp of evaporator air nozzle 2 Teoc Temperature evaporator chamber outside ceiling Teof Temp erature evaporator chamber outside floor Teow Temperature evaporator chamber outside wall Teri Temperature of refrigerant at evaporator inlet Tero Temperature of refrigerant at evaporator outlet Tgi Outdoor glycol temp in Tgi2 Indoor glycol temp in Tgo Outdoor glycol temp out Tgo2 Indoor glycol temp out Tori Temperature before the expansion device**SA E J276**  **5 Issued Proposed Draft 23MA**  **R2006**

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- Trcpi Temperature of refrigerant at compressor inlet Trcpo Temperature of refrigerant at compressor outlet Ts Temperature of steam in indoor chamber Tw Temperature of condensate (out of evaporator) T_cond Condensing temperature T_evap_in Evaporating tem perature at inlet state T_evap_out Evaporating tem perature at outlet state Vc Compressor speed [rpm] Vn_c1 Specific volume at conde nser nozzle 1 Vn_c2 Specific volume at condenser nozzle 2 Vn_e1 Specific volume at evaporator nozzle 1 Vn_e2 Specific volume at evaporator nozzle 2 Wc Power for 1st blower plus heaters
- outdoor chamber [W ] Wc 2 Power for 2nd blower
- outdoor cham ber [W ] Wc i Humidity ratio at condenser inlet We Power for blower and heater
- indoor chamber [W ] We i Evaporator inlet humidity ratio We n Humidity ratio after evaporator nozzles W_comp Compressor power [W ] Xoil Oil circulation rate x_in Evapo rator inlet quality x_out Evaporator exit quality**SA E J276**  **5 Issued Proposed Draft 23MA**  **R2006**

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- **11. Standard References**

1 ANSI/ASHRAE Standard 41.1
- 1986 (RA 2001), Standard Method for Temperature Measurement,

Am erican Society

of Heating, Refrigerating, and Air
- Conditioning Engineers. 2 ANSI/ASHRAE Standard 41. 6
- 1994 (RA 2001), Standard Method for Measurement of Moist Air

Properties, American Society of Heating, Refrigerating, and Air
- Conditioning Engineers. 3 ASHRAE Standard 41.3
- 1989, Standard Method for Pressure Measurement, American Society of Heating, Refr igerating, and Air
- Conditioning Engineers. 4 Fluid Meters
- Their Theory and Application
- Sixth Edition, 1971. Am erican Society of Mechanical Engineers, New York, NY. 5 ARI Standard 700
- 2004, Specifications for fluorocarbon refrigerants. Air
- Conditioning and Refrigeration

Institute. 6 ASHRAE Standard 41.2
- 1987 (RA 92), Standard Methods for Laboratory Airflow Measurement, Am erican Society

of Heating, Refrigerating, and Air
- Conditioning Engineers. 7 ANSI/ASHRAE Standard 51
- 1999
- Laboratory Methods of Testing F ans for Aerody nam ic Performance Rating (AMCA Standard 210
- 99), American Society of Heating, Refrigerating, and Air
Conditioning Engineers. 8 ANSI/ASHRAE Standard 37
- 2005, Methods of Testing for Rating Electrically Driven Unitary

Air
Conditioning and Heat P um p Equipm ent, American Society of Heating, Refrigerating, and Air
- Conditioning Engineers. 9 ANSI/ASHRAE Standard 41.4
- 1996, Standard Method for Measurement of Proportion of Lubricant in

Liquid Refrigerant, American Society of Heating, Refrigerating, and A ir
- Conditioning Engineers. 10 NIST Standard Reference Database 23, NIST Thermody nam ic and Transport Properties of Refrigerants

and Refrigerants and Refrigerant Mixtures

– REFPROP 6. National Institute of Standards and Technology , Gaithersburg, MD