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Heat transfer properties of HFE and R134a based Al2O3 nano refrigerant in thermosyphon for enhancing the heat transfer
Materials Today: Proceedings xxx (xxxx) xxx
Contents lists available at ScienceDirect
Materials Today: Proceedings journal homepage: www.elsevier.com/locate/matpr
Heat transfer properties of HFE and R134a based Al2O3 nano refrigerant in thermosyphon for enhancing the heat transfer R.S. Anand a, C.P. Jawahar b,⇑, A. Brusly Solomon c, Joel Suresh Koshy a, Johan C. Jacob a, Moncy M. Tharakan a a b c
Dept. of Mechanical Engineering, Karunya Institute of Technology and Sciences, Coimbatore, India Department of Mechanical Engineering, Amity University Madhya Pradesh, Gwalior 474 005, India Centre for Research in Material Science and Thermal Management, Dept. of Mechanical Engineering, Karunya Institute of Technology and Sciences, Coimbatore, India
a r t i c l e
i n f o
Article history: Received 16 July 2019 Accepted 2 November 2019 Available online xxxx Keywords: Heat transfer coefficient Nano refrigerant Refrigerant Thermal conductivity Thermosyphon
a b s t r a c t The nanoparticle dispersion in refrigerants is popular due to the increase in heat transfer performance in the Heating, Ventilation and Airconditioning system (HVAC). In the present study, Al2O3 nanoparticle of 0.025%, 0.05% and 0.075% volume concertation with the base fluid of the HFE 7000 is utilized; the nanoparticle volume concentration of 0.5%, 1.0% and 1.5% with R134a is used as working fluid in thermosyphon. It is found that the heat transfer characteristics are increased due to the addition of nanoparticle in refrigerants. Based on the analysis in this study it reveals about the heat transfer properties with the addition of nano refrigerants in thermosyphon. Thus, it concludes that the addition of nanoparticle in refrigerants enhances the thermal conductivity, viscosity to decreases the specific heat capacity when compared to the base fluids HFE 7000 and R134a refrigerants. The augmentation of volume concentration increases the thermal conductivity; besides it gains the average difference in thermal conductivity of 0.00443 W/mK and 0.03401 W/mK for the volume concentration of 0.075% in HFE and 1.5% in R134a with base HFE and R134a for given heat input. Ó 2019 Elsevier Ltd. All rights reserved. Selection and Peer-review under responsibility of the scientific committee of the First International Conference on Recent Advances in Materials and Manufacturing 2019.
1. Introduction Nano refrigerant is a refrigerant-based uniformly dispersed solid nanoparticle. The nanoparticle addition especially metal oxides in refrigerant varies the properties and increase the heat transfer performance [1]. Nano refrigerants are mainly used for lowtemperature applications such as air conditioning system and refrigeration, Vapor compression systems [2]. The application of nanoparticle in refrigerants was summarised by Ali celen et al. [3] and it reveals that the increase of nanoparticle quantity increases the rate of heat transfer and pressure drop but the size of the nanoparticle increases inverse the effect. In Vapour compression refrigeration system the heat transfer coefficient and thermal conductivity were increased up to 101% and 4% respectively which was reported by Sharifa et al. [4]. The nanoparticle with refrigerant in the refrigerator was reviewed by Nair et al. [5] and suggest that the usage of nanoparticle with refrigerant ⇑ Corresponding author. E-mail address: [email protected] (C.P. Jawahar).
increase the Coefficient of performance. The performance of copper oxide nanoparticle in R22 was studied by Anish et al. [6] in a refrigerator. It results that the usage of R22 and copper oxide increases the heat transfer and reduce energy consumption. The experimental studies using of Al2O3-R123 nano refrigerant was conducted by Jiang et al. [7] in organic Rankine cycle, it divulges that the heat transfer increases with the increase of heat source than pure R123. The flow boiling characteristics of the AlR141b was studied by Sun and Yang [8] in an internally threaded copper tube. The average heat transfer coefficient was increased up to 20% is observed than that of pure R141b. The effective heat transfer properties ZnO nanoparticles of cubical and spherical shape were studied with R134a refrigerant by Maheshwarya et al. [9]. The thermal conductivity of 42.5% and 25.26% was increased respectively for the cubical and spherical ZnO nanoparticles in R134a. Mahbubula et al. [10] examine the thermal conductivity, density and viscosity of the 0.1 to 0.4 vol% of Al2O3 nanoparticle in R141b refrigerant. The outcome finalizes that the thermal conductivity, viscosity and density of the nano-refrigerant increase with the increase of nanoparticle volume
https://doi.org/10.1016/j.matpr.2019.11.014 2214-7853/Ó 2019 Elsevier Ltd. All rights reserved. Selection and Peer-review under responsibility of the scientific committee of the First International Conference on Recent Advances in Materials and Manufacturing 2019.
Please cite this article as: R. S. Anand, C. P. Jawahar, A. B. Solomon et al., Heat transfer properties of HFE and R134a based Al2O3 nano refrigerant in thermosyphon for enhancing the heat transfer, Materials Today: Proceedings, https://doi.org/10.1016/j.matpr.2019.11.014
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concentration. The effect of nucleate boiling heat transfer on copper nanotubes in R22 with the volume concentration of 1% was studied by Park and Jung [11]. The study reveals that the boiling heat transfer coefficient of increased up to 24.7%. The thermal properties of Al2O3/R134a nano-refrigerant were studied by Mahbubul et al. [12] with mathematical correlations in a tube. The study concludes that the increase of concentration with small particle size enhances the thermal conductivity. The effect of the copper nanotube with R134A and R123on nucleate boiling in a tube is investigated by Park et al. [13] with a concentration of 1%. The enhancement of 63.6% is attained for the lower heat flux. The nanoparticle migration characteristics of pool boiling process were studied for copper oxide nanoparticle with R113refrigerant experimentally and numerically by Dinga et al. [14]. The result showed that migration mass of nanoparticle reduces with the increase of nanoparticle volume fraction. The Nano refrigerant thermal conductivity and viscosity of Al2O3 and R141b is studied by Mahbubul et al. [15] for the volume concentration of 0.5% to 2% from 5 to 20°. The result reveals that the thermal conductivity of the nano-refrigerant increase with the increase of the particle concentration. Naphon et al. [16] study the efficiency of heat pipe using R11 refrigerant and Titanium oxide nanoparticle as working fluid; the study divulges that the efficiency increases 1.40 times more than pure refrigerant. It is evident from the above literature that most of the work analyses the effect on nanoparticle concentration in refrigerants and the effectiveness of using nanoparticle in the refrigerator, HVAC and other systems. Thus, this work experimentally concludes the enhancement of heat transfer coefficient in thermosyphon using Al2O3 nanoparticle with the refrigerants HFE7000 and R134a. Moreover, the main focus of this study is to infer the reason for the increase in heat transfer properties such as thermal conductivity, viscosity and specific heat capacity in thermosyphon of nano refrigerants with the base refrigerants. 2. Experimental procedure 2.1. Working fluid The nanoparticle Al2O3 which reflects its size less than 30 nm since it possesses significant heat transfer property and available at a reasonable price. The base fluid of HFE with the nanoparticle volume concentration of 0.025%. 0.05% and 0.075% is utilized, moreover the base fluid R134a with the nanoparticle concentration of 0.5%, 1% and 1.5% is applied [12]. The Nano-refrigerant is prepared using a two-step process which includes the addition of nanoparticle in the base fluid. There is no sign that the addition of nanoparticle in the refrigerant is well mixed without any additional process. Hence the sonication process is used to disperse the nanoparticle in the base fluid. To avoid the evaporation of a refrigerant, the nano refrigerant is placed within the ultra-low reaction bath apparatus. The experiment may be disposed within the time duration of 3–4 h, the nano-refrigerant inside the ultralow bath apparatus is found to be stable for 5 h. 2.2. Fabrication of thermosyphon A thermosyphon is made up of a copper tube which is of length 350 mm is separated into various sections which include Evaporator and adiabatic of 100 mm each; and condenser of 150 mm. End caps are used to close the ends of the copper tube. Deoxidizing solution and Deionized water have been used to extract the dust and foreign particles from the copper tubes through the process of cleaning. Brazing is undertaken to close the copper tubes with the help of end caps. Helium leak detector apparatus has been used to check for leakages if any present in the thermosyphon. With the
support of the charging tube affixed with the condenser, the working fluid is being charged. To monitor the temperature in the thermosyphon, nine thermocouples are fixed within which two thermocouples are meant for evaporator and adiabatic, three thermocouples are deputed for the condenser section. To introduce heat in the evaporator section a nichrome wire flat heater is winded around it. 2.3. Experimentation Fig. 1 shows the schematic representation of the experiments were carried out in the thermosyphon. The evaporator section and adiabatic section is covered and insulated with the involvement of glass wool. This setup is used to reduce heat loss. Fig. 1 again, describes the array for the tests comprising of chilling unit, flow meter, data acquisition unit, wattmeter and a variable transformer. Condenser gets filled with cold water which is circulated by the chilling unit. A flow meter is adopted here to monitor the flow of the water. Data acquisition unit (Agilent – 34972A) gathers the information related to various T-type thermocouples and it is stored in the memory. An uncertainty factor of ±0.2 °C arises when the thermocouple is associated with the data logger. The temperature and flow rate measurement gives the inference of ±0.2% and ±3% uncertainty. 3. Results and discussion The experimentation is conducted for the various heat inputs from the range of 30 W to 150 W for the interval of 30 W. The heat transfer coefficient is obtained by heat flux to the temperature difference for the evaporator section. Fig. 2 shows the variation in the heat transfer coefficient of R134a/Al2O3 and HFE/ Al2O3 for heat inputs ranging from 30 W to 150 W. It can be observed that the heat transfer coefficient increases with an increase in heat input and the volume concentration of the nanoparticles, the similar results are also obtained by previous researchers [17]. It can be observed that the heat transfer coefficient of HFE also in which the maximum value is noted as 27.28784 kW/m2 °C for the combination of HFE/0.05 Al2O3. It can be noted that the heat transfer coefficient for HFE/0.05 Al2O3 is still increasing for the heat input of 150 W indicating the higher heat transfer capability of the thermosyphon due to the presence of nanoparticles. Similarly, for Fig. 2 the maximum range of heat transfer coefficient is noted for the combination of R134a/1.5Al2O3 and there is an increase of 94.9% when compared to the lowest heat transfer coefficient obtained for R134a. In addition, nanoparticle addition reduces the wall temperature indicating a higher heat transfer rate from the inner wall of the evaporator to the working fluid. The nano refrigerant properties of the R134a [18] and HFE are chosen 3 M Novec 7000 Engineering fluid [19] and Rausch et al. [20] for mean evaporator vapour temperature attained by the experiments. The thermal conductivity can be calculated by the below equation [21].
knr ¼ kb ð1 þ 10:5/Þ0:1051
ð1Þ
where, Kb is the thermal conductivity of the base fluid; / is the nanoparticle volume fraction. The specific heat and density of the nano-refrigerant are obtained from the model of Pak and Cho [22].
C P;nr ¼ ð1 /ÞC p;b þ / C p;p
ð2Þ
where, Cp,b and Cp,b are the base fluid and nanoparticle specific heat capacity respectively.
qnr ¼ ð1 /Þqb þ /qp
ð3Þ
Please cite this article as: R. S. Anand, C. P. Jawahar, A. B. Solomon et al., Heat transfer properties of HFE and R134a based Al2O3 nano refrigerant in thermosyphon for enhancing the heat transfer, Materials Today: Proceedings, https://doi.org/10.1016/j.matpr.2019.11.014
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Fig. 1. Schematic of experimental setup.
Fig. 2. Variation of Heat transfer coefficient of HFE/Al2O3 and R134a/Al2O3 for different heat inputs.
where, qb and qp are the base fluid and nanoparticle density respectively. The dynamic viscosity of the nano-refrigerant is attained by the equation [21].
lnr ¼ lb 1 þ
/ 12:5
6:356
where, lb is the dynamic viscosity of the base fluid.
ð4Þ
The variation of thermal conductivity of HFE/Al2O3 and R134a/ Al2O3 nanofluids for different heat loads ranging from 30 W to 150 W is depicted in Figs. 3a and 3b. It can be observed that there is a decrease in the trend of thermal conductivity when heat input is increased. This is due to that increase in heat input causes higher evaporation of R134a refrigerant, thus causing the molecules to vibrate at higher amplitude [12]. Even though there are many research works indicating that the thermal conductivity of
Please cite this article as: R. S. Anand, C. P. Jawahar, A. B. Solomon et al., Heat transfer properties of HFE and R134a based Al2O3 nano refrigerant in thermosyphon for enhancing the heat transfer, Materials Today: Proceedings, https://doi.org/10.1016/j.matpr.2019.11.014
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Fig. 3a. Variation of thermal conductivity of HFE/Al2O3 for different heat inputs.
Fig. 3b. Variation of thermal conductivity of R134a/Al2O3 for different heat inputs.
nanofluids increases with increase in volume concentration [10]. Rather for the lower concentration, a decrease in the trend can be observed with the rise in temperature. In addition, maximum thermal conductivity is observed for the volume concentration of 1.5% Al2O3 with R134a and 0.05% Al2O3 with HFE. The average increase in the value of thermal conductivity for the higher heat input is noted as 0.01571 W/mK and 0.03617 W/mK when compared to the lowest value obtained for both R134a and HFE respectively.
Figs. 4a and 4b indicates the viscosity characteristics of both HFE/Al2O3 and R134a/Al2O3 by increasing the heat load from 30 W to 150 W. It is observed that the viscosity value is decreased with increase in heat load. The difference in the percentage of viscosity for the maximum heat input between R134a/1.5% Al2O3 and pure R134a is noted as 38.247%. Whereas the difference between HFE/0.05% Al2O3 and pure HFE is noted as 0.3573 mPa.s. Initially, by adding nanoparticles, the covalent bond between the molecules becomes high which results in higher viscosity value as noted for
Please cite this article as: R. S. Anand, C. P. Jawahar, A. B. Solomon et al., Heat transfer properties of HFE and R134a based Al2O3 nano refrigerant in thermosyphon for enhancing the heat transfer, Materials Today: Proceedings, https://doi.org/10.1016/j.matpr.2019.11.014
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Fig. 4a. Variation of viscosity of HFE/Al2O3 for different heat inputs.
Fig. 4b. Variation of Viscosity of R134a/Al2O3 for different heat inputs.
R134a/1.5% Al2O3 and HFE/0.05% Al2O3. When the temperature is increased, the adhesive property between the molecules adjacent with each other reduces leading to decrease in viscosity of nanofluids [9]. Rather for pure HFE and R134a due to the absence of nanoparticles, the adhesion property is lesser at the initial stages followed by a reduction in viscosity at higher temperatures. Figs. 5a and 5b depicts the variation of specific heat capacity of nanofluids with respect to heat input. It can be noted that the
specific heat increases with increase in heat input. From Fig. 5a of HFE/Al2O3 nanoparticle, the volume concentration of 0.05% Al2O3 nanoparticle leads to the higher specific heat capacity of 1.4074 kJ/kg K with an average decrease of 2.905%. The maximum specific heat capacity is observed for R134a/1.5% Al2O3 nanofluid is noted as 1.8102 kJ/kg K with a rise of 2.3005 kJ/kg K for the pure R134a for the last heat input. Moreover, it can be noted that the specific heat of the base fluids (R134a and HFE) is lower when compared to the solid-liquid mixture [9].
Please cite this article as: R. S. Anand, C. P. Jawahar, A. B. Solomon et al., Heat transfer properties of HFE and R134a based Al2O3 nano refrigerant in thermosyphon for enhancing the heat transfer, Materials Today: Proceedings, https://doi.org/10.1016/j.matpr.2019.11.014
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Fig. 5a. Variation of Specific heat capacity of HFE/Al2O3 for different heat inputs.
Fig. 5b. Variation of Specific heat capacity of R134a/Al2O3 for different heat inputs.
4. Conclusions The following conclusions are drawn from the experimental studies and the heat transfer properties of the HFE/Al2O3 and R134a/Al2O3 Nano refrigerants in thermosyphon are The addition of Al2O3 nanoparticle in HFE 7000 and R134a increase the heat transfer characteristics of the thermosyphon. Hence it is identified that the addition Al2O3 increase the heat transfer.
The thermal conductivity and viscosity of nano refrigerant increase with the increase of the particle concentration also for all the heat input the thermal conductivity of increases for the nano refrigerant than pure base fluid. The specific heat capacity of the reduce up to 2.905% and 11.6% for 0.05% volume concentration of HFE and 1.5% volume concentration of R134 respectively. So, it is evident that the nanoparticle increases the thermal conductivity and viscosity hence the enhancement occurs in the nano-refrigerant charged thermosyphon.
Please cite this article as: R. S. Anand, C. P. Jawahar, A. B. Solomon et al., Heat transfer properties of HFE and R134a based Al2O3 nano refrigerant in thermosyphon for enhancing the heat transfer, Materials Today: Proceedings, https://doi.org/10.1016/j.matpr.2019.11.014
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Declaration of Competing Interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper. Acknowledgements The authors sincerely express our gratitude to Mr.Jeyaseelan, Technical Staff Centre for Research in Material Science and Thermal management, Karunya Institute of Technology and Sciences for his kind help. References [1] L. Cheng, L. Liu, Boiling and two-phase flow phenomena of refrigerant-based nanofluids: fundamentals, applications and challenges, Int. J. Refrig. 36 (2013) 421–446, https://doi.org/10.1016/j.ijrefrig.2012.11.010. [2] S.S. Sanukrishna, M.J. Prakash, An overview of experimental studies on nanorefrigerants: r.ecent research, development and applications, Int. J. Refrig. 88 (2018) 552–577, https://doi.org/10.1016/j.ijrefrig.2017.12.009. [3] A. Celen, A. Çebi, M. Aktas, O. Mahian, A.S. Dalkilic, S. Wongwises, A review of nanorefrigerants: flow characteristics and applications, Int. J. Refrig. 44 (2014) 125–140, https://doi.org/10.1016/j.ijrefrig.2014.05.009. [4] M.Z. Sharif, W.H. Azmi, R. Mamat, A.I.M. Shaiful, Mechanism for improvement in refrigeration system performance by using nanorefrigerants and nanolubricants – a review, Int. Commun. Heat Mass Transf. 92 (2018) 56–63, https://doi.org/10.1016/j.icheatmasstransfer.2018.02.012. [5] V. Nair, P.R. Tailor, A.D. Parekh, Nanorefrigerants: a comprehensive review on its past, present and future, Int. J. Refrig. 67 (2016) 290–307, https://doi.org/ 10.1016/j.ijrefrig.2016.01.011. [6] M. Anish, G. Senthil Kumar, N. Beemkumar, B. Kanimozhi, T. Arunkumar, Performance study of a domestic refrigerator using CuO/Al2O3-R22 nanorefrigerant as a working fluid, Int. J. Ambient Energy 0750 (2018) 1–5, https://doi.org/10.1080/01430750.2018.1451376. [7] F. Jiang, J. Zhu, G. Xin, Experimental investigation on Al2O3-R123 nanorefrigerant heat transfer performances in evaporator based on organic Rankine cycle, Int. J. Heat Mass Transf. 127 (2018) 145–153, https://doi.org/ 10.1016/j.ijheatmasstransfer.2018.07.061. [8] B. Sun, D. Yang, Experimental study on the heat transfer characteristics of nanorefrigerants in an internal thread copper tube, Int. J. Heat Mass Transf. 64 (2013) 559–566, https://doi.org/10.1016/j.ijheatmasstransfer.2013.04.031.
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[9] P.B. Maheshwary, C.C. Handa, K.R. Nemade, Effect of shape on thermophysical and heat transfer properties of ZnO/R-134a nanorefrigerant, Mater. Today: Proc. 5 (2018) 1635–1639, https://doi.org/10.1016/j.matpr.2017.11.257. [10] I.M. Mahbubul, R. Saidur, M.A. Amalina, Thermal conductivity, viscosity and density of R141b refrigerant based nanofluid, Proc. Eng. 56 (2013) 310–315, https://doi.org/10.1016/j.proeng.2013.03.124. [11] K.J. Park, D. Jung, Enhancement of nucleate boiling heat transfer using carbon nanotubes, Int. J. Heat Mass Transf. 50 (2007) 4499–45k02, https://doi.org/ 10.1016/j.ijheatmasstransfer.2007.03.012. [12] I.M. Mahbubul, S.A. Fadhilah, R. Saidur, K.Y. Leong, M.A. Amalina, Thermophysical properties and heat transfer performance of Al2O3/R-134a nanorefrigerants, Int. J. Heat Mass Transf. 57 (2013) 100–108, https://doi.org/ 10.1016/j.ijheatmasstransfer.2012.10.007. [13] K.J. Park, D. Jung, Boiling heat transfer enhancement with carbon nanotubes for refrigerants used in building air-conditioning, Energy Build. 39 (2007) 1061–1064, https://doi.org/10.1016/j.enbuild.2006.12.001. [14] G. Ding, H. Peng, W. Jiang, Y. Gao, The migration characteristics of nanoparticles in the pool boiling process of nanorefrigerant and nanorefrigerant-oil mixture, Int. J. Refrig. 32 (2009) 114–123, https://doi.org/ 10.1016/j.ijrefrig.2008.08.007. [15] I.M. Mahbubul, R. Saidur, M.A. Amalina, Influence of particle concentration and temperature on thermal conductivity and viscosity of Al2O3/R141b nanorefrigerant, Int. Commun. Heat Mass Transf. 43 (2013) 100–104, https://doi.org/10.1016/j.icheatmasstransfer.2013.02.004. [16] P. Naphon, D. Thongkum, P. Assadamongkol, Heat pipe efficiency enhancement with refrigerant-nanoparticles mixtures, Energy Convers. Manage. 50 (2009) 772–776, https://doi.org/10.1016/j.enconman.2008.09.045. [17] A.B. Solomon, R. Roshan, W. Vincent, V.K. Karthikeyan, L.G. Asirvatham, Heat transfer performance of an anodized two-phase closed thermosyphon with refrigerant as working fluid, Int. J. Heat Mass Transf. 82 (2015) 521–529, https://doi.org/10.1016/j.ijheatmasstransfer.2014.11.034. [18] P. Chart, in: Technical Guidelines R-134a Technical Guidelines Thermodynamic Properties Of R-134a, 2010, pp. 23–24. [19] Typical Physical Properties Novec 7000 Kinematic Viscosity, 3MTM NovecTM 7000 Eng. Fluid. (n.d.) 1–6. https://multimedia.3m.com/mws/media/121372O/3mnovec-7000-engineered-fluid-tds.pdf. [20] M.H. Rausch, L. Kretschmer, S. Will, A. Leipertz, Density, surface tension, and kinematic viscosity of hydrofluoroethers HFE-7000, HFE-7100, HFE-7200, HFE7300, and HFE-7500, J. Chem. Eng. Data 60 (2015) 3759–3765, https://doi.org/ 10.1021/acs.jced.5b00691. [21] L. Syam Sundar, M.K. Singh, A.C.M. Sousa, Investigation of thermal conductivity and viscosity of Fe3O4 nanofluid for heat transfer applications, Int. Commun. Heat Mass Transf. 44 (2013) 7–14, https://doi.org/10.1016/j. icheatmasstransfer.2013.02.014. [22] B.C. Pak, I. Cho Young, Hydrodynamic and heat transfer study of dispersed fluids with submicron metallic oxide particles, Exp. Heat Transf. (2007) 37–41, https://doi.org/10.1080/08916159808946559.
Please cite this article as: R. S. Anand, C. P. Jawahar, A. B. Solomon et al., Heat transfer properties of HFE and R134a based Al2O3 nano refrigerant in thermosyphon for enhancing the heat transfer, Materials Today: Proceedings, https://doi.org/10.1016/j.matpr.2019.11.014
Contents lists available at ScienceDirect
Materials Today: Proceedings journal homepage: www.elsevier.com/locate/matpr
Heat transfer properties of HFE and R134a based Al2O3 nano refrigerant in thermosyphon for enhancing the heat transfer R.S. Anand a, C.P. Jawahar b,⇑, A. Brusly Solomon c, Joel Suresh Koshy a, Johan C. Jacob a, Moncy M. Tharakan a a b c
Dept. of Mechanical Engineering, Karunya Institute of Technology and Sciences, Coimbatore, India Department of Mechanical Engineering, Amity University Madhya Pradesh, Gwalior 474 005, India Centre for Research in Material Science and Thermal Management, Dept. of Mechanical Engineering, Karunya Institute of Technology and Sciences, Coimbatore, India
a r t i c l e
i n f o
Article history: Received 16 July 2019 Accepted 2 November 2019 Available online xxxx Keywords: Heat transfer coefficient Nano refrigerant Refrigerant Thermal conductivity Thermosyphon
a b s t r a c t The nanoparticle dispersion in refrigerants is popular due to the increase in heat transfer performance in the Heating, Ventilation and Airconditioning system (HVAC). In the present study, Al2O3 nanoparticle of 0.025%, 0.05% and 0.075% volume concertation with the base fluid of the HFE 7000 is utilized; the nanoparticle volume concentration of 0.5%, 1.0% and 1.5% with R134a is used as working fluid in thermosyphon. It is found that the heat transfer characteristics are increased due to the addition of nanoparticle in refrigerants. Based on the analysis in this study it reveals about the heat transfer properties with the addition of nano refrigerants in thermosyphon. Thus, it concludes that the addition of nanoparticle in refrigerants enhances the thermal conductivity, viscosity to decreases the specific heat capacity when compared to the base fluids HFE 7000 and R134a refrigerants. The augmentation of volume concentration increases the thermal conductivity; besides it gains the average difference in thermal conductivity of 0.00443 W/mK and 0.03401 W/mK for the volume concentration of 0.075% in HFE and 1.5% in R134a with base HFE and R134a for given heat input. Ó 2019 Elsevier Ltd. All rights reserved. Selection and Peer-review under responsibility of the scientific committee of the First International Conference on Recent Advances in Materials and Manufacturing 2019.
1. Introduction Nano refrigerant is a refrigerant-based uniformly dispersed solid nanoparticle. The nanoparticle addition especially metal oxides in refrigerant varies the properties and increase the heat transfer performance [1]. Nano refrigerants are mainly used for lowtemperature applications such as air conditioning system and refrigeration, Vapor compression systems [2]. The application of nanoparticle in refrigerants was summarised by Ali celen et al. [3] and it reveals that the increase of nanoparticle quantity increases the rate of heat transfer and pressure drop but the size of the nanoparticle increases inverse the effect. In Vapour compression refrigeration system the heat transfer coefficient and thermal conductivity were increased up to 101% and 4% respectively which was reported by Sharifa et al. [4]. The nanoparticle with refrigerant in the refrigerator was reviewed by Nair et al. [5] and suggest that the usage of nanoparticle with refrigerant ⇑ Corresponding author. E-mail address: [email protected] (C.P. Jawahar).
increase the Coefficient of performance. The performance of copper oxide nanoparticle in R22 was studied by Anish et al. [6] in a refrigerator. It results that the usage of R22 and copper oxide increases the heat transfer and reduce energy consumption. The experimental studies using of Al2O3-R123 nano refrigerant was conducted by Jiang et al. [7] in organic Rankine cycle, it divulges that the heat transfer increases with the increase of heat source than pure R123. The flow boiling characteristics of the AlR141b was studied by Sun and Yang [8] in an internally threaded copper tube. The average heat transfer coefficient was increased up to 20% is observed than that of pure R141b. The effective heat transfer properties ZnO nanoparticles of cubical and spherical shape were studied with R134a refrigerant by Maheshwarya et al. [9]. The thermal conductivity of 42.5% and 25.26% was increased respectively for the cubical and spherical ZnO nanoparticles in R134a. Mahbubula et al. [10] examine the thermal conductivity, density and viscosity of the 0.1 to 0.4 vol% of Al2O3 nanoparticle in R141b refrigerant. The outcome finalizes that the thermal conductivity, viscosity and density of the nano-refrigerant increase with the increase of nanoparticle volume
https://doi.org/10.1016/j.matpr.2019.11.014 2214-7853/Ó 2019 Elsevier Ltd. All rights reserved. Selection and Peer-review under responsibility of the scientific committee of the First International Conference on Recent Advances in Materials and Manufacturing 2019.
Please cite this article as: R. S. Anand, C. P. Jawahar, A. B. Solomon et al., Heat transfer properties of HFE and R134a based Al2O3 nano refrigerant in thermosyphon for enhancing the heat transfer, Materials Today: Proceedings, https://doi.org/10.1016/j.matpr.2019.11.014
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concentration. The effect of nucleate boiling heat transfer on copper nanotubes in R22 with the volume concentration of 1% was studied by Park and Jung [11]. The study reveals that the boiling heat transfer coefficient of increased up to 24.7%. The thermal properties of Al2O3/R134a nano-refrigerant were studied by Mahbubul et al. [12] with mathematical correlations in a tube. The study concludes that the increase of concentration with small particle size enhances the thermal conductivity. The effect of the copper nanotube with R134A and R123on nucleate boiling in a tube is investigated by Park et al. [13] with a concentration of 1%. The enhancement of 63.6% is attained for the lower heat flux. The nanoparticle migration characteristics of pool boiling process were studied for copper oxide nanoparticle with R113refrigerant experimentally and numerically by Dinga et al. [14]. The result showed that migration mass of nanoparticle reduces with the increase of nanoparticle volume fraction. The Nano refrigerant thermal conductivity and viscosity of Al2O3 and R141b is studied by Mahbubul et al. [15] for the volume concentration of 0.5% to 2% from 5 to 20°. The result reveals that the thermal conductivity of the nano-refrigerant increase with the increase of the particle concentration. Naphon et al. [16] study the efficiency of heat pipe using R11 refrigerant and Titanium oxide nanoparticle as working fluid; the study divulges that the efficiency increases 1.40 times more than pure refrigerant. It is evident from the above literature that most of the work analyses the effect on nanoparticle concentration in refrigerants and the effectiveness of using nanoparticle in the refrigerator, HVAC and other systems. Thus, this work experimentally concludes the enhancement of heat transfer coefficient in thermosyphon using Al2O3 nanoparticle with the refrigerants HFE7000 and R134a. Moreover, the main focus of this study is to infer the reason for the increase in heat transfer properties such as thermal conductivity, viscosity and specific heat capacity in thermosyphon of nano refrigerants with the base refrigerants. 2. Experimental procedure 2.1. Working fluid The nanoparticle Al2O3 which reflects its size less than 30 nm since it possesses significant heat transfer property and available at a reasonable price. The base fluid of HFE with the nanoparticle volume concentration of 0.025%. 0.05% and 0.075% is utilized, moreover the base fluid R134a with the nanoparticle concentration of 0.5%, 1% and 1.5% is applied [12]. The Nano-refrigerant is prepared using a two-step process which includes the addition of nanoparticle in the base fluid. There is no sign that the addition of nanoparticle in the refrigerant is well mixed without any additional process. Hence the sonication process is used to disperse the nanoparticle in the base fluid. To avoid the evaporation of a refrigerant, the nano refrigerant is placed within the ultra-low reaction bath apparatus. The experiment may be disposed within the time duration of 3–4 h, the nano-refrigerant inside the ultralow bath apparatus is found to be stable for 5 h. 2.2. Fabrication of thermosyphon A thermosyphon is made up of a copper tube which is of length 350 mm is separated into various sections which include Evaporator and adiabatic of 100 mm each; and condenser of 150 mm. End caps are used to close the ends of the copper tube. Deoxidizing solution and Deionized water have been used to extract the dust and foreign particles from the copper tubes through the process of cleaning. Brazing is undertaken to close the copper tubes with the help of end caps. Helium leak detector apparatus has been used to check for leakages if any present in the thermosyphon. With the
support of the charging tube affixed with the condenser, the working fluid is being charged. To monitor the temperature in the thermosyphon, nine thermocouples are fixed within which two thermocouples are meant for evaporator and adiabatic, three thermocouples are deputed for the condenser section. To introduce heat in the evaporator section a nichrome wire flat heater is winded around it. 2.3. Experimentation Fig. 1 shows the schematic representation of the experiments were carried out in the thermosyphon. The evaporator section and adiabatic section is covered and insulated with the involvement of glass wool. This setup is used to reduce heat loss. Fig. 1 again, describes the array for the tests comprising of chilling unit, flow meter, data acquisition unit, wattmeter and a variable transformer. Condenser gets filled with cold water which is circulated by the chilling unit. A flow meter is adopted here to monitor the flow of the water. Data acquisition unit (Agilent – 34972A) gathers the information related to various T-type thermocouples and it is stored in the memory. An uncertainty factor of ±0.2 °C arises when the thermocouple is associated with the data logger. The temperature and flow rate measurement gives the inference of ±0.2% and ±3% uncertainty. 3. Results and discussion The experimentation is conducted for the various heat inputs from the range of 30 W to 150 W for the interval of 30 W. The heat transfer coefficient is obtained by heat flux to the temperature difference for the evaporator section. Fig. 2 shows the variation in the heat transfer coefficient of R134a/Al2O3 and HFE/ Al2O3 for heat inputs ranging from 30 W to 150 W. It can be observed that the heat transfer coefficient increases with an increase in heat input and the volume concentration of the nanoparticles, the similar results are also obtained by previous researchers [17]. It can be observed that the heat transfer coefficient of HFE also in which the maximum value is noted as 27.28784 kW/m2 °C for the combination of HFE/0.05 Al2O3. It can be noted that the heat transfer coefficient for HFE/0.05 Al2O3 is still increasing for the heat input of 150 W indicating the higher heat transfer capability of the thermosyphon due to the presence of nanoparticles. Similarly, for Fig. 2 the maximum range of heat transfer coefficient is noted for the combination of R134a/1.5Al2O3 and there is an increase of 94.9% when compared to the lowest heat transfer coefficient obtained for R134a. In addition, nanoparticle addition reduces the wall temperature indicating a higher heat transfer rate from the inner wall of the evaporator to the working fluid. The nano refrigerant properties of the R134a [18] and HFE are chosen 3 M Novec 7000 Engineering fluid [19] and Rausch et al. [20] for mean evaporator vapour temperature attained by the experiments. The thermal conductivity can be calculated by the below equation [21].
knr ¼ kb ð1 þ 10:5/Þ0:1051
ð1Þ
where, Kb is the thermal conductivity of the base fluid; / is the nanoparticle volume fraction. The specific heat and density of the nano-refrigerant are obtained from the model of Pak and Cho [22].
C P;nr ¼ ð1 /ÞC p;b þ / C p;p
ð2Þ
where, Cp,b and Cp,b are the base fluid and nanoparticle specific heat capacity respectively.
qnr ¼ ð1 /Þqb þ /qp
ð3Þ
Please cite this article as: R. S. Anand, C. P. Jawahar, A. B. Solomon et al., Heat transfer properties of HFE and R134a based Al2O3 nano refrigerant in thermosyphon for enhancing the heat transfer, Materials Today: Proceedings, https://doi.org/10.1016/j.matpr.2019.11.014
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Fig. 1. Schematic of experimental setup.
Fig. 2. Variation of Heat transfer coefficient of HFE/Al2O3 and R134a/Al2O3 for different heat inputs.
where, qb and qp are the base fluid and nanoparticle density respectively. The dynamic viscosity of the nano-refrigerant is attained by the equation [21].
lnr ¼ lb 1 þ
/ 12:5
6:356
where, lb is the dynamic viscosity of the base fluid.
ð4Þ
The variation of thermal conductivity of HFE/Al2O3 and R134a/ Al2O3 nanofluids for different heat loads ranging from 30 W to 150 W is depicted in Figs. 3a and 3b. It can be observed that there is a decrease in the trend of thermal conductivity when heat input is increased. This is due to that increase in heat input causes higher evaporation of R134a refrigerant, thus causing the molecules to vibrate at higher amplitude [12]. Even though there are many research works indicating that the thermal conductivity of
Please cite this article as: R. S. Anand, C. P. Jawahar, A. B. Solomon et al., Heat transfer properties of HFE and R134a based Al2O3 nano refrigerant in thermosyphon for enhancing the heat transfer, Materials Today: Proceedings, https://doi.org/10.1016/j.matpr.2019.11.014
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Fig. 3a. Variation of thermal conductivity of HFE/Al2O3 for different heat inputs.
Fig. 3b. Variation of thermal conductivity of R134a/Al2O3 for different heat inputs.
nanofluids increases with increase in volume concentration [10]. Rather for the lower concentration, a decrease in the trend can be observed with the rise in temperature. In addition, maximum thermal conductivity is observed for the volume concentration of 1.5% Al2O3 with R134a and 0.05% Al2O3 with HFE. The average increase in the value of thermal conductivity for the higher heat input is noted as 0.01571 W/mK and 0.03617 W/mK when compared to the lowest value obtained for both R134a and HFE respectively.
Figs. 4a and 4b indicates the viscosity characteristics of both HFE/Al2O3 and R134a/Al2O3 by increasing the heat load from 30 W to 150 W. It is observed that the viscosity value is decreased with increase in heat load. The difference in the percentage of viscosity for the maximum heat input between R134a/1.5% Al2O3 and pure R134a is noted as 38.247%. Whereas the difference between HFE/0.05% Al2O3 and pure HFE is noted as 0.3573 mPa.s. Initially, by adding nanoparticles, the covalent bond between the molecules becomes high which results in higher viscosity value as noted for
Please cite this article as: R. S. Anand, C. P. Jawahar, A. B. Solomon et al., Heat transfer properties of HFE and R134a based Al2O3 nano refrigerant in thermosyphon for enhancing the heat transfer, Materials Today: Proceedings, https://doi.org/10.1016/j.matpr.2019.11.014
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Fig. 4a. Variation of viscosity of HFE/Al2O3 for different heat inputs.
Fig. 4b. Variation of Viscosity of R134a/Al2O3 for different heat inputs.
R134a/1.5% Al2O3 and HFE/0.05% Al2O3. When the temperature is increased, the adhesive property between the molecules adjacent with each other reduces leading to decrease in viscosity of nanofluids [9]. Rather for pure HFE and R134a due to the absence of nanoparticles, the adhesion property is lesser at the initial stages followed by a reduction in viscosity at higher temperatures. Figs. 5a and 5b depicts the variation of specific heat capacity of nanofluids with respect to heat input. It can be noted that the
specific heat increases with increase in heat input. From Fig. 5a of HFE/Al2O3 nanoparticle, the volume concentration of 0.05% Al2O3 nanoparticle leads to the higher specific heat capacity of 1.4074 kJ/kg K with an average decrease of 2.905%. The maximum specific heat capacity is observed for R134a/1.5% Al2O3 nanofluid is noted as 1.8102 kJ/kg K with a rise of 2.3005 kJ/kg K for the pure R134a for the last heat input. Moreover, it can be noted that the specific heat of the base fluids (R134a and HFE) is lower when compared to the solid-liquid mixture [9].
Please cite this article as: R. S. Anand, C. P. Jawahar, A. B. Solomon et al., Heat transfer properties of HFE and R134a based Al2O3 nano refrigerant in thermosyphon for enhancing the heat transfer, Materials Today: Proceedings, https://doi.org/10.1016/j.matpr.2019.11.014
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Fig. 5a. Variation of Specific heat capacity of HFE/Al2O3 for different heat inputs.
Fig. 5b. Variation of Specific heat capacity of R134a/Al2O3 for different heat inputs.
4. Conclusions The following conclusions are drawn from the experimental studies and the heat transfer properties of the HFE/Al2O3 and R134a/Al2O3 Nano refrigerants in thermosyphon are The addition of Al2O3 nanoparticle in HFE 7000 and R134a increase the heat transfer characteristics of the thermosyphon. Hence it is identified that the addition Al2O3 increase the heat transfer.
The thermal conductivity and viscosity of nano refrigerant increase with the increase of the particle concentration also for all the heat input the thermal conductivity of increases for the nano refrigerant than pure base fluid. The specific heat capacity of the reduce up to 2.905% and 11.6% for 0.05% volume concentration of HFE and 1.5% volume concentration of R134 respectively. So, it is evident that the nanoparticle increases the thermal conductivity and viscosity hence the enhancement occurs in the nano-refrigerant charged thermosyphon.
Please cite this article as: R. S. Anand, C. P. Jawahar, A. B. Solomon et al., Heat transfer properties of HFE and R134a based Al2O3 nano refrigerant in thermosyphon for enhancing the heat transfer, Materials Today: Proceedings, https://doi.org/10.1016/j.matpr.2019.11.014
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Declaration of Competing Interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper. Acknowledgements The authors sincerely express our gratitude to Mr.Jeyaseelan, Technical Staff Centre for Research in Material Science and Thermal management, Karunya Institute of Technology and Sciences for his kind help. References [1] L. Cheng, L. Liu, Boiling and two-phase flow phenomena of refrigerant-based nanofluids: fundamentals, applications and challenges, Int. J. Refrig. 36 (2013) 421–446, https://doi.org/10.1016/j.ijrefrig.2012.11.010. [2] S.S. Sanukrishna, M.J. Prakash, An overview of experimental studies on nanorefrigerants: r.ecent research, development and applications, Int. J. Refrig. 88 (2018) 552–577, https://doi.org/10.1016/j.ijrefrig.2017.12.009. [3] A. Celen, A. Çebi, M. Aktas, O. Mahian, A.S. Dalkilic, S. Wongwises, A review of nanorefrigerants: flow characteristics and applications, Int. J. Refrig. 44 (2014) 125–140, https://doi.org/10.1016/j.ijrefrig.2014.05.009. [4] M.Z. Sharif, W.H. Azmi, R. Mamat, A.I.M. Shaiful, Mechanism for improvement in refrigeration system performance by using nanorefrigerants and nanolubricants – a review, Int. Commun. Heat Mass Transf. 92 (2018) 56–63, https://doi.org/10.1016/j.icheatmasstransfer.2018.02.012. [5] V. Nair, P.R. Tailor, A.D. Parekh, Nanorefrigerants: a comprehensive review on its past, present and future, Int. J. Refrig. 67 (2016) 290–307, https://doi.org/ 10.1016/j.ijrefrig.2016.01.011. [6] M. Anish, G. Senthil Kumar, N. Beemkumar, B. Kanimozhi, T. Arunkumar, Performance study of a domestic refrigerator using CuO/Al2O3-R22 nanorefrigerant as a working fluid, Int. J. Ambient Energy 0750 (2018) 1–5, https://doi.org/10.1080/01430750.2018.1451376. [7] F. Jiang, J. Zhu, G. Xin, Experimental investigation on Al2O3-R123 nanorefrigerant heat transfer performances in evaporator based on organic Rankine cycle, Int. J. Heat Mass Transf. 127 (2018) 145–153, https://doi.org/ 10.1016/j.ijheatmasstransfer.2018.07.061. [8] B. Sun, D. Yang, Experimental study on the heat transfer characteristics of nanorefrigerants in an internal thread copper tube, Int. J. Heat Mass Transf. 64 (2013) 559–566, https://doi.org/10.1016/j.ijheatmasstransfer.2013.04.031.
7
[9] P.B. Maheshwary, C.C. Handa, K.R. Nemade, Effect of shape on thermophysical and heat transfer properties of ZnO/R-134a nanorefrigerant, Mater. Today: Proc. 5 (2018) 1635–1639, https://doi.org/10.1016/j.matpr.2017.11.257. [10] I.M. Mahbubul, R. Saidur, M.A. Amalina, Thermal conductivity, viscosity and density of R141b refrigerant based nanofluid, Proc. Eng. 56 (2013) 310–315, https://doi.org/10.1016/j.proeng.2013.03.124. [11] K.J. Park, D. Jung, Enhancement of nucleate boiling heat transfer using carbon nanotubes, Int. J. Heat Mass Transf. 50 (2007) 4499–45k02, https://doi.org/ 10.1016/j.ijheatmasstransfer.2007.03.012. [12] I.M. Mahbubul, S.A. Fadhilah, R. Saidur, K.Y. Leong, M.A. Amalina, Thermophysical properties and heat transfer performance of Al2O3/R-134a nanorefrigerants, Int. J. Heat Mass Transf. 57 (2013) 100–108, https://doi.org/ 10.1016/j.ijheatmasstransfer.2012.10.007. [13] K.J. Park, D. Jung, Boiling heat transfer enhancement with carbon nanotubes for refrigerants used in building air-conditioning, Energy Build. 39 (2007) 1061–1064, https://doi.org/10.1016/j.enbuild.2006.12.001. [14] G. Ding, H. Peng, W. Jiang, Y. Gao, The migration characteristics of nanoparticles in the pool boiling process of nanorefrigerant and nanorefrigerant-oil mixture, Int. J. Refrig. 32 (2009) 114–123, https://doi.org/ 10.1016/j.ijrefrig.2008.08.007. [15] I.M. Mahbubul, R. Saidur, M.A. Amalina, Influence of particle concentration and temperature on thermal conductivity and viscosity of Al2O3/R141b nanorefrigerant, Int. Commun. Heat Mass Transf. 43 (2013) 100–104, https://doi.org/10.1016/j.icheatmasstransfer.2013.02.004. [16] P. Naphon, D. Thongkum, P. Assadamongkol, Heat pipe efficiency enhancement with refrigerant-nanoparticles mixtures, Energy Convers. Manage. 50 (2009) 772–776, https://doi.org/10.1016/j.enconman.2008.09.045. [17] A.B. Solomon, R. Roshan, W. Vincent, V.K. Karthikeyan, L.G. Asirvatham, Heat transfer performance of an anodized two-phase closed thermosyphon with refrigerant as working fluid, Int. J. Heat Mass Transf. 82 (2015) 521–529, https://doi.org/10.1016/j.ijheatmasstransfer.2014.11.034. [18] P. Chart, in: Technical Guidelines R-134a Technical Guidelines Thermodynamic Properties Of R-134a, 2010, pp. 23–24. [19] Typical Physical Properties Novec 7000 Kinematic Viscosity, 3MTM NovecTM 7000 Eng. Fluid. (n.d.) 1–6. https://multimedia.3m.com/mws/media/121372O/3mnovec-7000-engineered-fluid-tds.pdf. [20] M.H. Rausch, L. Kretschmer, S. Will, A. Leipertz, Density, surface tension, and kinematic viscosity of hydrofluoroethers HFE-7000, HFE-7100, HFE-7200, HFE7300, and HFE-7500, J. Chem. Eng. Data 60 (2015) 3759–3765, https://doi.org/ 10.1021/acs.jced.5b00691. [21] L. Syam Sundar, M.K. Singh, A.C.M. Sousa, Investigation of thermal conductivity and viscosity of Fe3O4 nanofluid for heat transfer applications, Int. Commun. Heat Mass Transf. 44 (2013) 7–14, https://doi.org/10.1016/j. icheatmasstransfer.2013.02.014. [22] B.C. Pak, I. Cho Young, Hydrodynamic and heat transfer study of dispersed fluids with submicron metallic oxide particles, Exp. Heat Transf. (2007) 37–41, https://doi.org/10.1080/08916159808946559.
Please cite this article as: R. S. Anand, C. P. Jawahar, A. B. Solomon et al., Heat transfer properties of HFE and R134a based Al2O3 nano refrigerant in thermosyphon for enhancing the heat transfer, Materials Today: Proceedings, https://doi.org/10.1016/j.matpr.2019.11.014