INTERNATIONAL JOURNAL OF ADVANCED RESEARCH IN ENGINEERING AND TECHNOLOGY (IJARET)

INTERNATIONAL JOURNAL OF ADVANCED RESEARCH IN ENGINEERING AND TECHNOLOGY (IJARET) International Journal of Advanced Research in Engineering and Technology (IJARET), ISSN 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 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 178

I INTRODUCTION India falls in the hot zone therefore the comfort air-conditioning has always been felt to be a 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 refrigeration. 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 units, the more commonly used one is Room Air- till 50Ton. conditioners, and then comes the Packaged systems which are used for higher tonnages Ever since the invention of Air Conditioning as one of Refrigeration application by W H Carrier in US in earlier 19 th 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 consistss 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 o C to 55 o C. While indoor side has either 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 method. These two rooms are separated by an opening in to which the non-ducted equipment (test air conditioner) is mounted which the non-ducted equipment (test air conditioner) is mounted. The equipments associated with air conditioner test room as follows: (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 Fig.2 Split AC Indoor Unit Installation 179

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 o C WBT o C DBT o C WBT o C 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. 180

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 o C Outdoor side conditions o C 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 =C i *A i *Y i * 2D p /p*3600*0.5885 Where ρ=density of air at the air sampling condition kg/m 3. C i = Discharge co-efficient of its nozzle dimensionless. Ai=Area of the nozzle in m 2. Yi=expansion factor, dimensionless. Dp=pressure drop across the nozzle in Pa. C i, Y i can be calculated from ASHRAE 41 FORMULAE FOR COOLING CAPACITY CALCULATIONS: Volume Flow rate of air Q va (m 3 /sec)= Cfm/2118.88 Enthalpy difference D h = Enthalpy of moist air entering - Enthalpy of moist air leaving Mass flow rate of air M a (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 o C Ambient: Entering air conditions: DBT-27.11 o C,WBT-19.27 o C 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 181

Saturation pr. at WBT, P l = 610.78*EXP(WBT/(WBT+238.3)*17.2694)/1000 v = 610.78*EXP(19.27/(19.27+238.3)*17.2694)/1000 = 2.2232 kpa Actual vapour pressure, l l P v = P v -(((P t - P v )*(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) Density of moist air, Den = 1/Ven = 1/0.8653 = 1.1556 kg/m 3 = 0.8654 m 3 /kg Leaving air conditions: DBT-13.78 o C,WBT-12.25 o C 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 182

Specific volume of air, Vle = (287.3*(273+DBT))/((Pt-Pv)*1000) = (287.3*(273+13.78))/((101.325-1.3199)*1000) = 0.8238 m 3 /kg Density of moist air, Dle = 1/Vle = 1/0.8238 =1.2138 kg/m 3 Calculations for Cooling capacity : Area, Ai = ((22/7*4)*SQRT(48.66/1000))+((22/7*4)*SQRT(99.43/1000)) = 0.00962 m 2 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 Enthalpy difference, Dh = hen-hle = 54.3878-34.5613 = 19.8265 kj/kg = 0.2562 m 3 /sec 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 183

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 o C WBT o C DBT o C WBT o C 27 19 35 24 CALCULATIONS Power Consumption Test of AC at 35 o C 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 46 o C 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. 184

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 DBT27 o C, WBT-19 o C and Outdoor side room DBT-35 o C, WBT-24 o C. After reaching the stable conditions and optimizing for 3 to 4 hours record the data of pressures (standard suction 70±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 (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 Discharge line 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 35 o 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 o C ambient. Similarly cooling capacity at 46 o C and 54 o C 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 35 o C Ambient. At 46 o C Ambient it is found that it consumes 24.5 Kwhr units of power i.e 1.021 kw/hr in Air conditioner test room. 185

10 8 6 4 EER 2 0 35 46 54 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. 186