Performance evaluation of a air conditioner according to different test standards

International Journal of Advanced Research in Engineering and Technology (IJARET), ISSN

0976 – 6480(Print), ISSN 0976 – 6499(Online) Volume 4, Issue 3, April (2013), © IAEME

178

PERFORMANCE EVALUATION OF A AIR CONDITIONER

ACCORDING TO DIFFERENT TEST STANDARDS

K. Ravi Kumar,

Asst Prof., Department of Mechanical Engineering,

AHCET, Chevella, Ranga Reddy – 515002(A.P.), India.

K. Ganesh Babu Asst Prof., Department of Mechanical Engineering,

SITECH, Chevella, Ranga Reddy – 515002(A.P.), India

S. Udaya Bhaskar Asso Prof., Department of Mechanical Engineering,

AHCET, Chevella, Ranga Reddy – 515002(A.P.), India.

ABSTRACT

The Paper reports on the performance of Air Conditioner at different test standards. The

future design of air conditioners is being driven primarily by (a) increased energy efficiency standards

and (b) the need to eliminate ozone-depleting working fluids. Various national and international

agencies continue to impose more stringent requirements for energy efficiency. In addition, consumer

pressure to select units with lower operating costs further drives the need for improved performance.

The main objective of this paper is to give wide understand of the standards and to maintain the

standard conditions in Psychrometric room (Air conditioner test room), which has been constructed to

test the air conditioners and to establish different test procedures. The tests that should be performed

in Air conditioner test room are cooling capacity test, power consumption test. The main objective of

the manufacturers is to produce the systems according to requirements of customers which can give

more cooling, low power consumption, high EER to with stand competition in the market. In every

country, the manufacturers follow some standards according to the climatic conditions to test the

appliances.

Keywords: Psychrometric room; EER; cooling capacity test; power consumption test; climatic

conditions

INTERNATIONAL JOURNAL OF ADVANCED RESEARCH IN

ENGINEERING AND TECHNOLOGY (IJARET)

ISSN 0976 - 6480 (Print) ISSN 0976 - 6499 (Online) Volume 4, Issue 3, April 2013, pp. 178-186 © IAEME: www.iaeme.com/ijaret.asp Journal Impact Factor (2013): 5.8376 (Calculated by GISI) www.jifactor.com

IJARET

© I A E M E

International Journal of Advanced Research in Engineering and


I INTRODUCTION

India falls in the hot zone therefore the comfort air

necessity for mankind. To achieve comfort, heat is extracted from the comfort region and transferred

to the environment, which is at a higher temperature. This is done with the help of r

Though there are many methods to achieve cooling, one process that is predominantly applied in

refrigeration equipment and its application is vapor compression cycle. One of the applications of

vapor compression system is in Air conditioning

conditioners, and then comes the Packaged systems which are used for higher tonnages till 50Ton.

Ever since the invention of Air Conditioning as one of Refrigeration application by W H Carrier in

US in earlier 19th Century, there has been a radical change in the methods and process used in

manufacturing air-conditioning equipment but there is no change in the principle i.e. Vapor

compression system used in the cycle.

II.EXPERIMENTAL SETUP

Air conditioner test room is constructed according to ASHREA standards. It consists of two rooms

made of adiabatic material of rigid polyurethane, one is indoor side room and another is outdoor side

room. The outside room ambient is controlled from 25

temperature control or load control. For testing or air conditioner, maintaining of temperatures is

important so these two rooms are made of adiabatic material. The method use in air conditioner test

room for finding capacity is air enthalpy

which the non-ducted equipment (test air conditioner) is mounted which the non

(test air conditioner) is mounted.

The equipments associated with air conditioner test room as follo

(a) Panel Boards

(b) Split AC Indoor Unit Installation

(c) Split AC Outdoor Unit Installation

(d) Packaged Air conditioners

(e) Humidifiers

(f) Code Tester

(g) Temperature measuring instrument

(h) Heaters

(g) Sampling device

Fig.1. Psychrometric Laboratory view


6499(Online) Volume 4, Issue 3, April (2013), © IAEME

179

therefore the comfort air-conditioning has always been felt to be a


to the environment, which is at a higher temperature. This is done with the help of r



vapor compression system is in Air conditioning units, the more commonly used one is Room Air



Century, there has been a radical change in the methods and process used in

conditioning equipment but there is no change in the principle i.e. Vapor

compression system used in the cycle.

room is constructed according to ASHREA standards. It consists of two rooms


room. The outside room ambient is controlled from 25oC to 55

oC. While indoor s



room for finding capacity is air enthalpy method. These two rooms are separated by an opening in to

ducted equipment (test air conditioner) is mounted which the non-ducted equipment

The equipments associated with air conditioner test room as follows:

Split AC Indoor Unit Installation

Split AC Outdoor Unit Installation

Temperature measuring instrument

sychrometric Laboratory view Fig.2 Split AC Indoor Unit Installation

Technology (IJARET), ISSN


conditioning has always been felt to be a


to the environment, which is at a higher temperature. This is done with the help of refrigeration.



units, the more commonly used one is Room Air-



Century, there has been a radical change in the methods and process used in

conditioning equipment but there is no change in the principle i.e. Vapor

room is constructed according to ASHREA standards. It consists of two rooms


C. While indoor side has either



method. These two rooms are separated by an opening in to

ducted equipment

Split AC Indoor Unit Installation



180

Fig.3 Split AC Outdoor Unit Installation Fig.4. Code Tester

Fig.5. Temperature Measuring Device

III. COOLING CAPACITY TEST AND CALCULATIONS

TEST CONDITIONS: The test conditions that should be maintained are as follows:

ISO 5151 standard

Indoor side Outdoor side

DBT oC WBT

oC DBT

oC WBT

oC

27 19 35 24

PROCEDURE

Out let of air conditioner (which is going to be tested) is attached to the receiving chamber of

the code tester through the proper ducting. Before starting the main switch, ensure that all the

switches of panel Board are in disable or not. Before starting the test, clean all the sensors and fill

water in all sampling devices. Set the temperatures values, which are going, to be maintained in PID’S

of the panel boards Switch on the test unit by adjusting dimmer to 230 volts.



181

For example: we are maintaining DBT–35°C, WBT-24°c in outdoor side and DBT-27°C, WBT-

19°C indoor side (according to ISO standard) When temperature is stabilized there arithmetic mean

value should have

Outdoor side conditions oC Outdoor side conditions

oC

DBT 35±0.3 DBT 27±0.3

WBT 24±0.2 WBT 19±0.2

After stabilization, to maintain the test conditions for 4 hours, and record the data after 30 minutes so

that there are 7 set of readings for every 5 min.

During this 30 min duration, record the code tester nozzle pressure drop. When receiving

chamber pressure shows 0.0 and record code tester DBT and WBT readings also.

The sensor temperature that should be recorded are:

102 Indoors side DBT

103 Indoors side WBT

104 Outdoors side DBT

105 Outdoors side WBT

106 Indoor side Code tester DBT

107 Indoor side Code tester WBT

Average the recorded data. So that we can get more appropriate one value.

For convenience not indoor side room temperature from 102 and 103 sensors and leaving air

condition from 106 and 107 sensors.

For calculation of CFM:

Cfm =Ci*Ai*Yi*√2Dp/p*3600*0.5885

Where

ρ=density of air at the air sampling condition kg/m3.

Ci= Discharge co-efficient of its nozzle dimensionless.

Ai=Area of the nozzle in m2.

Yi=expansion factor, dimensionless.

Dp=pressure drop across the nozzle in Pa.

Ci, Yi can be calculated from ASHRAE 41

FORMULAE FOR COOLING CAPACITY CALCULATIONS:

Volume Flow rate of air Qva(m3/sec)= Cfm/2118.88

Enthalpy difference Dh = Enthalpy of moist air entering - Enthalpy of moist air leaving

Mass flow rate of air Ma(kg/s) =Volume flow rate of air/Specific volume of air

Cooling capacity in KW =Mass flow rate of air*Enthalpy difference

Cooling capacity in Btu/hr=Cooling capacity in KW*3412.14

Cooling capacity in Ton of refrigeration=Cooling capacity in KW/3.5167

CALCULATIONS

Calculations at 35 oC Ambient:

Entering air conditions: DBT-27.11oC,WBT-19.27

oC

Saturation pr.at DBT,

Ps= 610.78*EXP(DBT/(DBT+238.3)*17.2694)/1000

= 610.78*EXP(27.11/(27.11+238.3)*17.2694)/1000

= 3.5642 kpa



182

v

Saturation pr. at WBT, P l

= 610.78*EXP(WBT/(WBT+238.3)*17.2694)/1000

= 610.78*EXP(19.27/(19.27+238.3)*17.2694)/1000

= 2.2232 kpa

Actual vapour pressure, l l

Pv = Pv -(((Pt- Pv )*(DBT-WBT)*(1.8))/(2800-1.3((1.8*DBT)+32))

= 2.2232-(((101.325-2.2232)*(27.11-19.27)*(1.8))/(2800-1.3((1.8*27.11)+32))

= 1.7042 kpa

Humidity ratio, W = 0.622*(Pv/(Pt-Pv))

= 0.622*(1.7042/(101.325-1.7042))

= 0.01064

Enthalpy of moist air, hen = (1.005*DBT) + (W*(2500+(1.88*DBT)))

= (1.005*27.11) + (0.01064*(2500+(1.88*27.11)))

= 54.3878 kj/kg

Specific volume of air, Ven = (287.3*(273+DBT))/((Pt-Pv)*1000)

= (287.3*(273+27.11))/((101.325-1.7042)*1000)

= 0.8654 m3/kg

Density of moist air, Den = 1/Ven

= 1/0.8653

= 1.1556 kg/m3

Leaving air conditions: DBT-13.78o

C,WBT-12.25oC

Saturation pr. at DBT,

Ps = 610.78*EXP(DBT/(DBT+238.3)*17.2694)/1000

= 610.78*EXP(13.78/(13.78+238.3)*17.2694)/1000

= 1.5699 kpa

Saturation pr. At WBT,

P = 610.78*EXP(WBT/(WBT+238.3)*17.2694)/1000

= 610.78*EXP(12.25/(12.25+238.3)*17.2694)/1000

= 1.4209 kpa40

Actual vapour pressure,

l

Pv = Pv -(((Pt- Pv )*(DBT-WBT)*(1.8))/(2800-1.3((1.8*DBT)+32))

= 1.4209-(((101.325-1.4209)*(13.78-12.25)*(1.8))/(2800-1.3((1.8*13.78)+32))

= 1.3199 kpa

Humidity ratio, W = 0.622*(Pv/(Pt-Pv))

= 0.622*(1.3199/(101.325-1.3199))

= 0.0082

Enthalpy of moist air, hle = (1.005*DBT) + (W*(2500+(1.88*DBT)))

= (1.005*13.78) + (0.0082*(2500+(1.88*13.78)))

= 34.5613 kj/kg



183

Specific volume of air, Vle = (287.3*(273+DBT))/((Pt-Pv)*1000)

= (287.3*(273+13.78))/((101.325-1.3199)*1000)

= 0.8238 m3/kg

Density of moist air, Dle = 1/Vle

= 1/0.8238

=1.2138 kg/m3

Calculations for Cooling capacity :

Area, Ai = ((22/7*4)*SQRT(48.66/1000))+((22/7*4)*SQRT(99.43/1000))

= 0.00962 m2

Cubic flow per minute,

Cfm = Ci*Yi*Ai*SQRT((2*Dp)/Dle)*3600*0.5885

=0.985*0.998*0.00962*SQRT((2*445)/1.2138)*3600* 0.5885

= 542.56 or 543

Volume flow rate,Qva= Cfm/2118.88

= 543/2118.88

= 0.2562 m3/sec

Enthalpy difference, Dh = hen-hle

= 54.3878 - 34.5613

= 19.8265 kj/kg

Mass flow rate, Ma = Volume flow rate (Qva)/Specific volume of leaving air (Vle)

= 0.2562/0.8238

= 0.3109 kg/sec

Cooling capacity in KW = Mass flow rate (Ma)*Enthalpy difference (Dh)

= 0.3109*19.8265

= 6.1640 kw

Cooling capacity in Btu/hr = cooling capacity in kw*3412.14

= 6.1640*3412.14

= 21032.43 Btu/hr

Cooling capacity in TON of refrigeration = cooling capacity in kw / 3.516

= 6.1640 / 3.516

= 1.7531 Ton

Energy efficiency ratio,EER = (cooling capacity in Btu/hr) / (Input power in watts)

= 21032/2240

= 9.389 Btu/W-hr



184

POWER CONSUMPTION TEST

Test conditions: The various test conditions that should be maintained for Power consumption test are as

Follows:ISO 5151 Standard

Indoor side Outdoor side

DBT oC WBT oC DBT oC WBT oC

27 19 35 24

CALCULATIONS

Power Consumption Test of AC at 35oC Ambient

Power consumed by air conditioner for 24hr = Final Energy meter reading –

Initial Energy meter reading

=5332.7 – 5316.2

= 16.5 Kw-hr

Power consumed of 1hr = 16.5/24

=0.687 Kw/hr

Power Consumption Test of AC at 46oC Ambient

Power consumed by air conditioner for 24hr = Final Energy meter reading –

Initial Energy meter reading

=5358.5 – 5334

= 24.5 Kw-hr

Power consumed of 1hr = 24.5/24

=1.021 Kw/hr

STARTABILITY TEST

Test conditions: -

The various test conditions that should be maintained are given below:

(a) BIS 1391:1992

Indoor side room °C Outdoor side room °C Voltage

DBT WBT DBT WBT V

35 24 46 27 90% &110% of rated voltage.

(b) BIS 1391:1992(For Export A &B)

Indoor side room °C Outdoor side room °C Voltage

DBT WBT DBT WBT V

32 23 43 26 90% &110% of rated voltage.

32

23

52

31

95% minimum voltage&110%

of maximum voltage with dual

rated voltage.

International Journal of Advanced Research in Engineering and


Procedure for Down Trip:

(1) Take the cold resistance of the system (i.e. Main, Auxiliary and Total resistances) before

starting the system.

(2) Start the appliance at 220/230V according to the request by maintaining Indoor sideroom

DBT27oC, WBT-19

oC and Outdoor side room DBT

stable conditions and optimizing for 3 to 4 hours record the data of pressures (standard

suction 70±5 psig anddischarge 300

placed at different places in the applian

(a) Indoor side room DBT and WBT

(b) Outdoor side room DBT and WBT

(c) Top shell and bottom shell

(d) Condenser in and condenser out

(e) Evaporator in an evaporator out

(f) Suction line and Dischar

IV RESULTS AND CONCLUSIONS

Every product that is manufactured is tested to know how it works and up to what level it can

satisfy the requirements of customers. The main objective of this project is testing the Air conditioner

appliance according to different standards by maintaining different climatic conditions in Air

conditioner test room. The testing includes cooling test, power consumption test.

From capacity test, cooling capacity of system at different temperatures is known. Cooling

capacity test is done on air conditioner appliance. The specification given by manufacturer for cooling

capacity of Air Conditioner at 35oC ambient is 21200 Btu/hr, by conducting capacity test in the Air

conditioner test room it is found that its capacity is lower

Similarly cooling capacity at 46oC and 54

Figure

Power consumption test is done on air conditioner and found that it

16.5 Kwhr units power i.e 0.687 kw/hr at 35

24.5 Kwhr units of power i.e 1.021 kw/hr in Air conditioner test room.



185

Take the cold resistance of the system (i.e. Main, Auxiliary and Total resistances) before

Start the appliance at 220/230V according to the request by maintaining Indoor sideroom

C and Outdoor side room DBT-35 o

C, WBT-24 o

C. After reaching the


5 psig anddischarge 300±10 psig), temperatures, current and power. Sensors are

placed at different places in the appliance to record the temperatures of the following

Indoor side room DBT and WBT

Outdoor side room DBT and WBT

Top shell and bottom shell

Condenser in and condenser out

Evaporator in an evaporator out

Suction line and Discharge line

IV RESULTS AND CONCLUSIONS



to different standards by maintaining different climatic conditions in Air

conditioner test room. The testing includes cooling test, power consumption test.


test is done on air conditioner appliance. The specification given by manufacturer for cooling

C ambient is 21200 Btu/hr, by conducting capacity test in the Air

conditioner test room it is found that its capacity is lower by 1.4% i.e 20908 Btu/hr at 35

C and 54oC ambient is found as 19332Btu/hr and 5582 Btu/hr.

Figure 6 EER Vs Temperature

Power consumption test is done on air conditioner and found that it consumes when operated for 24 hr

16.5 Kwhr units power i.e 0.687 kw/hr at 35oC Ambient. At 46oC Ambient it is found that it consumes

24.5 Kwhr units of power i.e 1.021 kw/hr in Air conditioner test room.

Technology (IJARET), ISSN


Take the cold resistance of the system (i.e. Main, Auxiliary and Total resistances) before

Start the appliance at 220/230V according to the request by maintaining Indoor sideroom

C. After reaching the


10 psig), temperatures, current and power. Sensors are

ce to record the temperatures of the following



to different standards by maintaining different climatic conditions in Air


test is done on air conditioner appliance. The specification given by manufacturer for cooling

C ambient is 21200 Btu/hr, by conducting capacity test in the Air

by 1.4% i.e 20908 Btu/hr at 35oC ambient.

C ambient is found as 19332Btu/hr and 5582 Btu/hr.

consumes when operated for 24 hr

C Ambient it is found that it consumes



186

Figure 7 Power(Units) Vs Temperature

The various factors observed amidst the testing were, amount of charge of refrigerant,

pressure drop, suction and discharge pressures, power, current etc. From these work different

procedures for testing air conditioners are established. The test results will give awareness to the

customers and manufacturers. Useful data is generated for the air conditioning engineers.

REFERENCES

[1] Akintunde, M.A. 2004b. Experimental Investigation of The performance of Vapor

Compression Refrigeration Systems. Federal University of Technology, Akure, Nigeria

[2] American Society Heating Refrigeration and Air Conditioning. ASHRAE Hand Book. 2001

[3] Wernick, B.J. “Effectiveness method”, RACA journal 2004.

[4]. C.P Arora, Refrigeration and Air conditioning. Tata McGraw-Hill Book Company

[5]. Stoecker, W.F. and Jones J.W. (1982), Refrigeration & Air Conditioning. McGraw-Hill Book

Company, Singapore

[6] Analytical expressions for optimum flow rates in evaporators and condensers of heat pumping

systems International Journal of Refrigeration, Volume 33, Issue 7, November 2010,

Pages 1211-1220 Granryd, E.

[7] Yumrutas R, kunduz M, Kanoglu M. Exergy analysis of vapor compression refrigeration

systems. Exergy, An international journal 2002;2(4);266-72.

[8] Dr.S.S. Banwait and Dr.S.C. Laroiya, “Properties of refrigerant and psychometric tables

and charts

[9] “Technical Manual Air-conditioning application, Tecumseh”. Tecumseh Products India Pvt.

Ltd., Hyderabad.

[10] Calorimeter Test Facility Lab manual (CTFLM) Tecumseh Products India Pvt. Ltd.

[11] Eckert, E.R.G.; Goldstein, R.J.; Ibele, W.E.; Patankar, S.V.; Simon, T.W.; Strykowski, P.J.;

Tamma, K.K.; Kuehn, T.H.; Bar-Cohen, A.; Heberlein, J.V.R.; (Sep 1997), Heat transfer--a

review of 1994 literature, International Journal of Heat and Mass Transfer 40-16, 3729-3804.

[12] N. Thangadurai and Dr. R. Dhanasekaran, “Effective Power Consumption Model for a

Network With Uniform Traffic Pattern”, International Journal of Computer Engineering &

Technology (IJCET), Volume 3, Issue 2, 2012, pp. 561 - 570, ISSN Print: 0976 – 6367, ISSN

Online: 0976 – 6375.

[13] Kapil Chopra, Dinesh Jain, Tushar Chandana and Anil Sharma, “Evaluation of Existing

Cooling Systems for Reducing Cooling Power Consumption”, International Journal of

Mechanical Engineering & Technology (IJMET), Volume 3, Issue 2, 2012, pp. 210 - 216,

ISSN Print: 0976 – 6340, ISSN Online: 0976 – 6359.

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Performance evaluation of a air conditioner according to different test standards

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