Experimental Analysis Of Vapour Compression Refrigeration .
Special Issue - 2015International Journal of Engineering Research & Technology (IJERT)ISSN: 2278-0181TITCON-2015 Conference ProceedingsExperimental Analysis of Vapour CompressionRefrigeration System using Al2O3/CuO-R134aNano Fluid as Refrigerant1T. Coumaressin., 2K. Palaniradja., 3R. Prakash., 4V. Vinoth Kumar1Research Scholar, Department of Mechanical Engineering, Pondicherry Engineering College2Professor, Department of Mechanical Engineering, Pondicherry Engineering College3,4Department of Mechanical Engineering, Sri Manakula Vinayagar Engineering CollegePondicherry, INDIAAbstract –The objective of this paper is to investigate theinfluence of Al2O3/CuO nano particles on the heat transfercharacteristics and performance of refrigerant basednanofluid flow through the vapour compression refrigerationsystem. As a replacement to CFC’s and HFC’s, R134arefrigerant is being widely used in current refrigeration andair-conditioning systems. But they consume more power andhas high global warming potential. By addition of thenanoparticles to the refrigerant results in improvements inthe thermo physical properties and heat transfercharacteristics of the refrigerant, thereby improving theperformance of the refrigeration system. An experimentalapparatus was build according to the national standards ofIndia. Aluminium oxide and copper oxide nano fluids areused with R134a refrigerant in vapour compressionrefrigeration system and the heat transfer coefficient andperformance of the system were evaluated by using TKSolver, using nano concentration 0 to 1%.The experimentalresults shows that the heat transfer coefficient of refrigerantbased nanofluid is higher than that of pure refrigerant andalso coefficient of performance is higher than the existing.Index terms - Aluminium oxide, COP, Copper oxide, heattransfer coefficient, nano refrigerant, R134a, TK solver.1 predominantly used for refrigeration and air-conditioningsystems nowadays. R134a refrigerant has replaced theCFC’s and HFC’s as they were said to have high ozonedepleting potential. R134a has its own negatives like globalwarming potential, high power consumption and so on. Inorder to overcome current power scarcity, energy efficientrefrigeration system with high heat transfer coefficient hasto be developed. Nanofluids are thermal fluids prepared bysuspending nano sized particles in conventional base fluids(water, ethylene glycol, refrigerant). Nanofluids are said tohave higher thermal conductivity when compared to thebase fluids and hence are said to improve the heat transfercharacteristics of the base fluids. These thermo physicalproperties of nano fluids make it possible to be used inrefrigeration systems. Eed Abdel Hafez et al [1] hadperformed heat transfer analysis of vapour compressionVolume 3, Issue 16refrigeration system using CuO – R134a and found thatheat transfer co-efficient of refrigerant increases with 0.1 to0.55% of CuO and 15 to 25 nm size of CuO Nano investigation of R152a/R134a mixture in refrigerationsystem using hydrocarbon mixtures of R152a and R134aand concluded that the system worked safely and themaximum cop value 5.26 has obtained. HaoPeng et al [5]studied heat transfer characteristics of refrigerant basednano fluid flow boiling inside a horizontal smooth tubeusing CuO R113 and observed that heat transfercoefficient R113 CuO mixture is larger than that of purerefrigerant and 29.7 % of maximum heat transfercoefficient. T.Coumaressin et al [7] had conductedperformance analysis of a refrigeration system using Nanofluid and concluded that evaporator heat transfer coefficient increases with usage of Nano CuO-R134a. Juancarlos et al [9] studied applications of nano fluid inrefrigeration system and found greater reduction ofevaporator area with usage of Cu H2O nano fluid.D.Senthilkumar and Dr.R.Elansezhian [10] conductedexperimental study on Al2O3-R134a nano refrigerant inrefrigeration system with 0.2% nano concentration andobtained increase of COP as 3.5 for capillary length of10.5m. N.Subramani and M.J.Prakash [11] conducted anexperimental study on vapour compression refrigerationsystem using nano refrigerants with Al2O3 and foundincrease of Co-efficient of heat transfer by 58%, reductionof power consumption by 18% and increase in COP by33%.The main objectives of the paper are (i) To improve theheat transfer characteristics in refrigerator system byadding Al2O3/CuO nano particles to the R134a refrigerant.(ii) To perform the heat transfer analysis and performanceanalysis in a vapour compression refrigeration systemusing a nanofluid as refrigerant. (iii) To develop amathematical model for such a system. (iv) To performheat transfer and performance analysis using TK Solversoftware. (v) To evaluate the heat transfer coefficients andCoefficient of performance for different concentrations ofAl2O3/CuO nano particles and to come up with anoptimized Al2O3/CuO concentration to maximize the heatPublished by, www.ijert.org1
Special Issue - 2015International Journal of Engineering Research & Technology (IJERT)ISSN: 2278-0181TITCON-2015 Conference Proceedingstransfer coefficient, Coefficient of performance andrefrigeration effect.Table 1. Observations from the refrigeration test rig2 EXPERIMENTAL SETUPObservationEvaporator, Reciprocating Compressor, Condenser,Expansion valve – solenoid Valve, Refrigerant – R134aEvaporator vessel diameter, D 295mm 0.295mEnergy meter constant,E 750 rev/kWh2.1 WorkingThe vapour – compression uses a circulating liquidrefrigerant as a medium which absorbs and removes heatfrom the space to be cooled and subsequently rejects thatheat elsewhere. Figure 1 depicts the typical, single – stagevapour – compression system. All such systems have 4components: A compressor, a condenser, a thermalexpansion valve and an evaporator. Circulating refrigerantenters the compressor in the thermodynamic state known asa saturated vapour and is compressed to a higher pressure,resulting in a higher temperature as well. The hot vapour isrouted through a condenser where it is cooled andcondensed into a liquid by flowing through a coil or tubeswith cool air flowing across the coil or tubes.The condensed liquid refrigerant, in the thermodynamicstate known as a saturated liquid, is next routed through anexpansion valve where it undergoes an abrupt reduction inpressure. That pressure reduction results in the adiabaticflash evaporation of a part of the liquid refrigerant. Thecold mixture is then routed through the coil or tubes in theevaporator. A fan circulates the warm air in the enclosedspace across the coil or tubes carrying the cold refrigerantliquid and vapour mixture. That warm air evaporates theliquid part of the cold refrigerant mixtures. At the sametime, the circulating air is cooled and thus lowers thetemperature of enclosed space to the desired temperature.Experiment was conducted using the above setup usingR134a pure refrigerant and the actual and theoretical COPof solenoid valve and expansion valve expansion arecalculated and the following results are obtained.Initial temp of water (ºC)Final temp of water (ºC)Pressure at comp. Inlet (bar)Pressure at comp. Outlet (bar)Pressure before throttling (bar)Pressure after throttling (bar)Temp. at compressor inlet (ºC)Temp. at compressor outlet(ºC)Temp. before throttling (ºC)Temp. after throttling (ºC)Mass of water 610.92462.226130.0876.2441216.395Table2. Performance of VCRS using pure R134a.Sl.NoCOPSolenoidValveExpansionValve12COP actualCOP theoretical0.78472.97471.11273.89513Refrigeration effect(kJ/Kg)0.25860.47342.2 ConclusionsThe conclusions from the experiment were:Expansion valve can be preferred over solenoid valve asan expansion device. Refrigeration effect can be enhancedin the evaporator. To enhance the refrigeration effect, weshould use a better refrigerant. Nano particles-Al2O3/CuOcan be used as refrigerant. We can improve the heat transfercoefficient, Coefficient of performance in a designedevaporator section.3 MATHEMATICAL MODELLINGRefrigerant to be usedNanofluid: R134a: Al2O3, CuO3.1 Thermophysical properties of Nano refrigerantThe thermal conductivity of refrigerant based nanofluidis calculated by Hamilton – Crosser equation [16]K 2K 2φ(Kr Kn )K rn K r ( n r)Kn 2Kr φ(Kr Kn )(1)Where,Krn– Thermal conductivity of nano refrigerantKr - Thermal conductivity of pure refrigerant (R134a)Kn - Thermal conductivity of nano particleφ - Particle volume fraction of nano particleThe dynamic viscosity of nano refrigerant is calculatedby Brinkman equation [18]. The Dynamic viscosity of nanorefrigerant is as given below,1μrn μr (1 φ)2.5Figure 1. VCRS experimental setupVolume 3, Issue 16(2)Where,μr– Viscosity of pure refrigerantφ– Particle volume fractionPublished by, www.ijert.org2
Special Issue - 2015International Journal of Engineering Research & Technology (IJERT)ISSN: 2278-0181TITCON-2015 Conference ProceedingsThe specific heat capacity of nano refrigerant iscalculated by Pak-cho equation (Pak and Cho, 1998). Thespecific heat of nano refrigerant is as given below.Cp rn (1 φ)Cp r φCp n(3)Where,φ – Particle volume fractionCp-r – Specific heat of refrigerantCp-n – Specific heat of nano particleThe Reynolds’s number of nano refrigerant can becalculated from the equation given below [16]G DiRern μrn(4)Where,G - mass flux 100 Kg/m2sDi - Inner diameter of tubeμrn - Viscosity of nano refrigerantThe Prandtl number of nano refrigerant can becalculated from the equation given below [16]Prrn Cp rn μrn3.3 Coefficient of performanceActual COP of a vapour compression refrigerationsystem is given byhA TCOPAct (13)V ICoefficient of performance of the refrigeration(COP)actualRefrigerationeffectCOP actual (14)WorkdoneTheoretical COP of a vapour compression refrigerationsystem is given byH HCOPTheo 2 1(15)H4 H2Krn(5)The Nusselt number of nano refrigerant can becalculated from the equation given below [16]Nu 0.023Rern0.8Prrn0.4(6)The volume fraction of nano particles used in the abovegiven equations can be obtained using the below relation[5]ωρrϕ ωρr (1 ω)ρn(7)Where,ω - Mass fraction of nano particleρr - Density of pure refrigerant R134aρn - Density of nano particleThe relation for mass fraction of nano particle is given below [5]Mnω (8)Mn MrWhere,Mn – Mass of nano particlesMn – Mass of pure refrigerant (R134a)Convective heat transfer coefficient of nano refrigerantis given by the following relation [16]1hc rn 0.023 [Tf – Final temperature of waterCp – Specific heat of water 4.186 KJ/Kg KdT – Duration of experiment in secWork done by the compressor360010Work done KW(12)EtWhere,E – Energy meter constant 750 rev/ kWhT – Time taken for 10 revolution of the energy meter discG4 Cp rn 2 krn 3 5Di μrn 2]3.2 Formula for Experimental calculationMass of water in the evaporator vesselm Density of water Volume of waterπm ρ D2 hKg/sec4Where,ρ - Density of waterD – Diameter of vessel 295 mm 0.295 mh – Height of water in vesselHeat absorbed from evaporator water,mcp (Ti Tf )Refrigeration effect J/secdTWhere,Ti – initial temperature of waterVolume 3, Issue 16(9)(10)(11)Where,H1 – Enthalpy of refrigerant at the inlet of evaporator.H2 – Enthalpy of refrigerant at the outlet of evaporator.H4 – Enthalpy of refrigerant at the outlet of compressor.Table 3. Properties of Nano fluids and R134a.DensitySpecific heat(J/kgK)1432729535.6FluidR134aAl2O3CuOThermal conductivity(W/mK0.08034020(kg/m3)1199.7388065004 RESULTS AND DISCUSSION4.1 Analysis and comparison of thermo physical propertiesof nano refrigerantsThe thermo physical properties such as heat transfercoefficient, thermal conductivity, specific heat capacity anddynamic viscosity of Al2O3/CuO – R134a nano refrigerantare calculated using TK Solver and their properties foroptimized nano concentration are tabulated below.Table 4. Thermo physical properties of Al2O3-R134a 20.17061239.19212280.0395Table 5. Thermo physical properties of CuO-R134a 14601237.63811884.6961*Where 𝜔 Mass fraction of nano particles, hrn Heattransfer coefficient of nano refrigerant, Krn Thermalconductivity of nano refrigerant, Cprn Specific heatcapacity of nano refrigerant, and 𝜇𝑟𝑛 Dynamic viscosityPublished by, www.ijert.org3
Special Issue - 2015International Journal of Engineering Research & Technology (IJERT)ISSN: 2278-0181TITCON-2015 Conference Proceedingsof nano refrigerant respectively.Heat transfer coefficient of Al2O3 and CuO nanorefrigerants are compared below. The curve rises graduallyand then decreases as shown in the below figure. The peakvalue is achieved at 0.55% concentration of Al2O3 and at0.6% concentration of CuO nano refrigerant.Figure 5. Dynamic viscosity of Al2O3 and CuO4.2 Comparison of performance of Al2O3&CuOThe parameters obtained from the experiment conductedon vapour compression refrigeration system using pureR134a refrigerant are used to calculate the performance ofthe system with nano refrigerant of various compositionand the coefficient of performance for different nanorefrigerant combinations with solenoid as well expansionvalve are calculated using TK solver and are tabulatedbelow.Figure 2. Heat transfer coefficient of Al2O3 and CuOThe curves of thermal conductivity of Al2O3 and CuOnano refrigerants are compared in the below figure. Thecurve seems to rise gradually as shown below.Table 6. Performance of Nano R134a refrigerant inVCRSCoefficient Of PerformanceAl2O3SolenoidValve2.6911Figure 3. Thermal conductivity of Al2O3 and CuOThe characteristics curve for specific heat capacity ofAl2O3 and CuO nano refrigerant decreases gradually asshown ansionValve3.703The performance of vapour compression refrigerationsystem (solenoid valve) using Al2O3 and CuO nanorefrigerants are calculated and compared below. The peakCOP is obtained at 0.55% concentration of Al2O3(COP 2.6911) and 0.6% concentration of CuO nanorefrigerant (COP 2.643)Figure 6. COP of Al2O3 and CuO –R134a nano refrigerants using solenoidvalveFigure 4. Specific heat capacity of Al2O3 and CuOThe curve for dynamic viscosity of Al 2O3 and CuO nanorefrigerants are compared below and seem to be increasinggradually.Volume 3, Issue 16The performance of vapour compression refrigerationsystem (expansion valve) using Al2O3 and CuO nanorefrigerants are calculated and compared below. The peakCOP is obtained at 0.55% concentration of Al2O3(COP 3.7699) and 0.6% concentration of CuO nanorefrigerant (COP 3.703)Published by, www.ijert.org4
Special Issue - 2015International Journal of Engineering Research & Technology (IJERT)ISSN: 2278-0181TITCON-2015 Conference ProceedingsREFERENCE[1][2]Figure 7. COP of Al2O3 and CuO –R134a nano refrigerants usingexpansion valve[3][4][5][6][7]Figure 8. Comparison of experimental average COP and peak nano COPThe above figure shows the comparison between theexperimental average actual COP of vapour compressionrefrigeration system using R134a and the peak actual COPof nano refrigerant at optimized nano concentrations. It isinferred from the above graph, that the COP of vapourcompression refrigeration system increases with optimizedmixing of nanofluids and Al2O3 is found to produce highCOP when compared to other three nano refrigerants takeninto account.5 CONCLUSION[9][10][11][12]Al2O3/CuO nano particles with R134a refrigerant can beused as an excellent refrigerant to improve the heat transfercharacteristics and performance in a refrigeration system. Asuccessful model has been designed and the basictheoretical heat transfer analysis and performance analysisof the refrigeration system has been done. Heat transfer andperformance analysis for the designed section has beensuccessfully performed using TK Solver software. Theobtained evaporating heat transfer coefficient andcoefficient of performance result have been optimized at itsmaximum value for the best Al2O3/CuO nano particlesconcentration in R134a refrigerant. From the analysis it canbe concluded that the heat transfer and performancecharacteristics of the system is higher with the usage ofAl2O3 nano particles with R134a refrigerant compared toCuO nano particles.Volume 3, Issue 16[8][13][14][15][16][17][18]Eed Abdel- Hafez, Abdel- Haddi, SherifHady Taker, Abdel HamidMohammed Tork, Sameer SabryHamad, “Heat transfer analysis of vapourcompression refrigeration system using CuO-R134a,” Internationalconference on Advanced materials engineering IPCSIT Vol. 15 (2011)TeshomeBekele, kotu&K.Reji Kumar, “Comparison of Heat transferperformance in domestic refrigerator using Nano Refrigerant and Double pipeheat exchanger”, School of mechanical & industrial engineering, BahirdarUniversity.R.Reji Kumar, K.Sridhar, M.Narasimha, “Heat transfer enhancement indomestic refrigerator using R600a/ mineral oil/ Nano-Al2O3 as working fluid,”International journal of computational engineering research, Vol. 03, issue. 4.D.Senthil Kumar, Dr.R.Elansezhian, “Investigation of R152a/ R134a mixturein refrigeration system,” International journal of Engineering and InnovativeTecchnology, Volume 2, issue 6, December 2012.HaoPeng, Gualiang Ding, Weitingjiang, Haitao Hi, Yifengao, “Heat transfercharacteristics of refrigerant based Nano fluid flow boiling inside a horizontalsmooth tube,” International journal of refrigeration 32 (2009) 1259-1270R.Krishnasabareesh, N.Gobinath, V.sajith, Sumitesh Das and C.B.Sobhan,“Application of TiO2 Nano particles as a lubricant additive for Vapourcompression refrigeration system – An experimental investigation,”International journal of refrigeration (2012), doi: 10.1016T.Coumaressin and K.Palaniradja, “Performance analysis of a refrigerationsystem using Nano fluid,” International journal of Advanced Mechanicalengineering, Research India publications. 2014. ISSN 2250-3234 Vol(4),Number(4) PP 459-470.Prof(Dr) R.S.Mishra, “Methods of improving thermodynamic performance ofvapour compression refrigeration system using twelve ecofriendly refrigerantsin primary circuit and Nano fluid (water based) in secondary circuit,”International journal of Engineering and Technology and AdvancedEngineering. ISSN 2250-2459 Vol. 4, Issue 6. June 2014.Juan Carlos-ValdeyLoaiza, Frank chaviano - purzaesky, Jose Alberto—ReisParise, “A Numerical Study on the applications of Nano fluids in refrigerationsystems,” International refrigeration and air conditioning conference, 2010Purdue University, Paper 1145D.Senthilkumar, Dr.R.Elansezhian, “Experimental study on Al2O3 – R134anano refrigerant in refrigeration system,” International journal of modernengineering research (IJMER), Vol.2, PP : 3927 – 3929 ISSN : 2249 – 6645.2012.N.Subramani, M.J.Prakash, “Experimental study on vapour compressionrefrigeration system using nano refrigerants,” Journal of engineering scienceand technology Vol.3, No.9, PP : 95-102. 2011.Shanmugasundaram, R.ShanthiandVelrajramalingam, “Heat transferenhancements using nano fluids,” Thermal science Vol: 16, No. 2, PP : 423 –444. 2012.Subramani.N, Ashwinmohan and Dr.M.Joseprakash, “Performance studies ona vapour compression refrigeration system using nanolubricant,” Internationaljournal of Innovative Research in Science, Engineering and Technology,Volume 2, Special issue 1, December 2013, ISSN 2347-6710N.Subramani and M.J.Prakash, “Experimental studies of vapour compressionrefrigeration system using nano refrigerant,” International journal ofengineering science and Technology, Vol. 3, No. 9, 2011, pp. 95-102Rahulkumarjaiswal and R.S.Mishra, “Performance evaluation of Vapourcompression refrigeration system using eco-friendly refrigerants 1o circuit and2o circuit (Nano particle),” International research journal of sustainablescience & engineering. Vol. 2, Issue – 5. May 2014R.Saidure et al,
Experimental Analysis of Vapour Compression Refrigeration System using Al 2 O 3 /CuO-R134a Nano Fluid as Refrigerant 1T. Coumaressin., 2K. Palaniradja., 3R. Prakash., 4V. Vinoth Kumar 1Research Scholar, Department of Mechanical Engineering, Pondicherry Engineering College 2Professor, Department of Mechanical Engineering, Pondicherry Engineering College
Performance (COP) of refrigeration cycle is developed. The investigations shows that various results are obtained for the effect of evaporating temperatures, condensing temperatures, degree of subcooling and effectiveness of liquid-vapour heat exchanger on COP, exergetic efficiency and EDR of theoretical vapour compression refrigeration cycle.
2. Cycle with wet vapor after compression, 3. Cycle with superheated vapor after compression, 4. Cycle with superheated vapor before compression, and 5. Cycle with under cooling or sub cooling of refrigerant, Advantages of Vapour Compression System : It has a smaller size for the given capacity of refrigeration. It has less running cost.
used refrigeration systems, and each system employs a compressor. Basic vapour compression refrigeration cycle consists of four major thermal processes; evaporation, compression, condensation and expansion. There are many applications where refrigeration plant is required to meet the v
Introduction Lossless Compression Algorithms There will be no data loss in this type of compression as it is defined by the name. Both original data and the compressed data are the same in this compression. The algorithms for the compression and decompression are exact inverse of each other in the Lossless Compression. The main mechanism in
4 COMPRESSION THERAPY BANDAGES Comprilan – Short Stretch Compression Bandage 24 JOBST Compri2 – 2-Layer Bandage System 25 JOBST Comprifore LF – Multi-Layer Compression Bandage 25 Tensopress – Long Stretch Compression Bandage 26 Gelocast – Zinc Paste Compression Bandage (Unna Boot) 26 COMPRESSION SYSTEMS JOBST UlcerCARE – Ready
Image Compression Model Image compression reduces the amount of data from the original image representation. There are two approaches to compress an image. These are: (a) Lossless compression (b) Lossy compression Fig.2.2 shows a general image compression model. Image data representation has redundancy (also called pixel
The mechanical sub-cooling of main VCR cycle has been carried out through the subcooler or evaporator of another simple VCR cycle designated as subcooler VCR cycle. (a) (b) Figure 2. (a) Schematic diagram of dedicated mechanically subcooled vapour compression refrigeration cycle, (b) P-h diagram of dedicated sub-cooled vapour compression cycle
AUTOMOTIVEEMC SAFETY&EMC2011 Table3ISO11452-2severitylevels SeverityLevel Field/(V/m) I25 II50 III75 IV100 V(opentotheusersofthestandard) Figure10Typicalbiconicalantenna
