Open access peer-reviewed chapter

Effect of Nanoparticles on Performance Characteristics of Refrigeration Cycle

Written By

Ravinder Kumar

Submitted: July 17th, 2019 Reviewed: August 19th, 2019 Published: November 27th, 2019

DOI: 10.5772/intechopen.89236

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Since few years, researchers are introduced nanorefrigerant in the recent development of refrigeration systems. This chapter briefly summarizes the behavior of different nanoparticles in vapor compression refrigeration cycle. The nanoparticles’ infusion in refrigeration cycle affects the viscous behavior of the refrigerant. It is found that very limited studies have been done on viscosity characteristics of nanolubricants, but few reports states that viscosity increases with nanoparticles additive which improves the tribology of compressor. But inversely, the increment of viscosity promotes to the possible pressure drop in the system which eventually drops the cycle performance. The optimum contribution of nanorefrigerant with high thermal conductivity and low viscosity is the success key of system performance with nanoparticles. However, it is found that the contribution of nanoparticles on the basis of physical phenomena that are affecting the vapor compression cycle is limited in the literature. This chapter aims to make a review on the mechanism of improving vapor compression cycle by using nanorefrigerants.


  • nanorefrigerants
  • nanolubricants
  • compressor work
  • coefficient of performance
  • heat transition

1. Introduction

Nanorefrigerant was defined to complete the objective of improving thermal performance using little possible fraction of nanoparticles in the base refrigerant. An improved term of refrigerant known as “nanorefrigerant” firstly introduced and experimentally implemented by Wang et al. [1]. The addition of nanoparticles in refrigerant improves the system performance in terms of improvement in flow and pool boiling heat transfer characteristics as well as flowing pool condensation heat transfer [2, 3]. Nowadays, nanorefrigerant and nanolubricant became a great alternate to enhance the performance of cooling cycles in terms of tribology performance, heat mass transfer properties and refrigerant/oil mixture relations [4, 5, 6, 7]. Specifically, nanorefrigerant improves the heat transfer coefficient at evaporation and condensation whereas a nanolubricant improves the tribology characteristics which ultimately increase the compressor performance. The expected volume concentration of nanoparticles is calculated using Eq. (1).


where, ø is the volume fraction in percentage, ρpand ρLare the density of nanoparticles and density of the lubricant respectively; and mpand mLare the masses of nanoparticles and lubricants respectively. The formation of nanorefrigerant is possible as shown in Figure 1.

Figure 1.

Formation of nanorefrigerant in VCR cycle.

The present chapter aims to define the mechanism that steers towards improvement in overall VCR cycle performance using nanolubricants and nanorefrigerants. The authors’ hope that this paper will be useful to define the research gaps and understands the contribution of nanorefrigerants and nanolubricants in refrigeration cycle.


2. Improvement in VCR system performance

The section consists of four sub-sections. First part concerns research findings related to Al2O3 nanoparticles and the other parts deals with review studies related to CuO, TiO2 and CNT nanoparticles. The schematic diagram of refrigeration cycle is shown in Figure 2.

Figure 2.

Schematic diagram of vapor compression refrigeration cycle.

2.1 Studies related to Al2O3

Till date, researchers developed various methods to improve heat transfer characteristics of refrigerants inside the vertical and horizontal tubes. Adding nanoparticles to base refrigerant is one of the most efficient methods to enhance the thermal characteristics of refrigerant.

Jwo et al. [8] dispersed 0.1% mass fraction of Al2O3 particles in polyester oil and reported 2.4% reduction in compressor work. Mahbubul et al. [9, 10] reported significant increment in thermal conductivity and viscosity with Al2O3 nanoparticles dispersed in R141b. Later, the author observed increment in heat transfer coefficient and pressure drop up to 383 and 181%, respectively using particle volume fraction between 1 and 5% with fixed mass flux of 100 kg/m2 s. Mahbubul et al. [11] reported large frictional pressure drop of R134a/Al2O3 nanorefrigerant as compared to R113/CuO nanorefrigerant flows inside horizontal smooth tube due to higher vapor quality [12].

Sun and Yang [13] studied the effect of Alumina-R141b, Cu-R141b, Al-R141b and CuO-R141b with mass fractions 0.1–0.3 wt% in a computer aided test rig on flow boiling heat transfer in horizontal tube and reported that Cu-R141b nanorefrigerant had the highest heat transfer coefficient as compared to other mixtures. Kedzierski [14] dispersed 1.6% volume fraction of Al2O3 in R134a/POE mixture flows on a horizontal and rough flat surface and found that higher volume fraction of nanoparticles with low average diameter has greater positive effect on heat transfer characteristics of base refrigerant. Further, Kedzierski [15] investigated the effect of Al2O3 nanoparticles on the pool boiling characteristics of R134a/POE mixture inside the rectangular finned surface and reported that 3.6% nanoparticle volume fraction enhanced the boiling heat transfer performance up to 113%. Tang et al. [16] reported that using δ-Al2O3 with R141b significantly improved pool boiling heat transfer coefficient in the system but adding surfactant at higher concentration corrupted the heat transfer process.

Mahbubul et al. [17] dispersed Al2O3 in R141b refrigerant for thermal conductivity and viscosity investigation. The author reported that viscosity and thermal conductivity of R141b/Al2O3 nanorefrigerant at 2% volume fraction are 179 and 1.626 times greater than pure refrigerant. Jwo et al. [8] used 0.05–2% weight fraction of Al2O3 particles with R134a and R12, respectively and reported that R134a refrigerant replaces R12, as polyester oil replaces mineral oil. Further, 0.1 wt% fraction of nanoparticles in R134a refrigerant reduced the energy consumption by 2.4% which significantly improved the COP of refrigerator. Kumar and Elansezhian [18] experimentally investigated the effect of R134a/Al2O3/PAG blend on the overall performance of VCR cycle and observed lower energy consumption by 10.32%. Author stated that using nanoparticle in refrigeration system is a cost effective method which improve its COP and length of capillary tube is reduced.

Subramani and Prakash [19] observed 25% less energy consumption and 33% overall COP enhancement in VCR cycle using Al2O3 nanorefrigerant. The freezing capacity of the cycle was also improved. Yusof et al. [20] dispersed 0.2% Al2O3 particles in polyester (POE) lubricant and reported 7% improvement in system COP and 2.1% reduction at compressor energy consumption. Cremaschi et al. [21] studies that alumina nanoparticles did not improve the solubility between refrigerant and lubricant, while addition of nanoparticles had slightly lowered the solubility of R410a/POE.

2.2 Studies related to CuO

Kedzierski and Gong [22, 23] observed heat transfer improvement between 50 and 275% using 0.5% mass fraction of CuO particles with R134a/RL68H and R134a/POE blend. Moreover, R134a/RL68H blend shows higher heat transfer enhancement as compared to the R134a/POE blend. In Later study, the author used 2 Vol% fraction of CuO particles in R134a refrigerant and reported nanorefrigerant has higher heat flux. Bartelt et al. [24] dispersed 0.5–1% mass fraction of CuO nanoparticles in R134a/polyester blend in horizontal flow boiling conditions and found 42–82% and 50–101% heat transfer enhancement for 1 and 2% mass fraction respectively. Peng et al. [25] dispersed 0.1 and 0.5 wt% CuO nanoparticles in R113 refrigerant to study heat transfer performance inside a horizontal rough pipe and reported 29.7% HTC using nanoparticles in base refrigerant. Henderson et al. [26] reported lower heat transfer performance with 0.5 and 0.05 vol% of CuO and SiO2 nanoparticles dispersed in R134a and R134a/POE blend during boiling flow conditions in horizontal tube. Further, the author used 0.02, 0.04 and 0.08 vol% of CuO nanoparticles in R134a/POE blend and observed that nanoparticle with 0.04 and 0.08 vol% improved heat transfer performance up to 52 and 76%, respectively. Kedzierski and Gong [27] dispersed 0.5% mass fraction of CuO nanoparticles in polyester oil and observed 275% improvement in heat transfer with base refrigerant R134a.

Later, Bartelt et al. [28] extended the experiment of Kedzierski and Gong [27] and observed that 2% concentration of CuO nanoparticles gives the highest improvement up to 101% (Tables 1 and 2) [29, 46].

Nanoparticles concentration0%0.2%0.4%0.6%0.8%1.0%
Energy consumption (kW)0.1130.1120.100.1070.1050.105
Energy saving (%)0.793.375.557.317.31

Table 1.

Compressor energy consumption using distinct nanoparticle fractions [29].

Nanoparticles concentration0%0.2%0.4%0.6%0.8%1.0%
Energy consumption (kW)0.13230.12780.12500.12360.12240.1224
Energy saving (%)3.405.516.577.487.48

Table 2.

Compressor energy consumption of LPG/MO mixture using distinct nanoparticle fractions [46].

Abdel-Hadi et al. [30] experimentally found that CuO nanoparticles with average size 25 nm and concentration 0.55% is an optimum value which significantly enhanced the evaporative heat transfer coefficient. Kumar et al. [29] observed 7% reduction in compressor energy consumption and 46% enhancement in COP with dispersion of 0.2–1 wt% fraction of CuO nanoparticles in compressor lubricant. Moreover, the author reported reduction in friction and wear in compressor using nanoparticles in base lubricant. Peng et al. [31] used Cu nanoparticle in R113/VG68 (ester oil) mixture. It was observed that using Cu nanoparticles with average size of 20 nm strongly improved the heat transfer performance up to 23.8% as compared to other particles sizes of 50 and 80 nm. Akhavan-Behabadi et al. [32] found 83% increment in heat transfer rate with 1.5% mass fraction of CuO nanoparticles dispersed in R600a/polyester oil condensed inside the smooth horizontal tube (Figures 3 and 4) [29, 41, 46].

Figure 3.

Viscous behavior of mineral oil appended with CuO nanoparticles [29].

Figure 4.

COP comparison of the refrigerant cycle appended with different refrigerants/nanoparticles.

2.3 Studies related to TiO2

Wang et al. [1] performed among the first experimental study using nanorefrigerant which proves that cooling speed and COP of domestic refrigerator significantly enhanced by utilizing TiO2 nanoparticles in R134a based system. Further, Jiang et al. [33] studied the thermal conductivity using new theory and compared with the experimental data using different R22 nanorefrigerant fractions. The investigation proved that particle aggregation theory and the resistance network is a useful method to calculate the thermal conductivity properties of nanorefrigerant. Li et al. [34] observed that significant improvement at heat transfer coefficient of R11 refrigerant using TiO2 particles. Trisaksri and Wongwises [35] experimentally observed that nucleate pool boiling heat transfer coefficient (HTC) of using R141b refrigerant decreases with increment of TiO2 nanoparticle fractions at high heat fluxes.

Mahbubul et al. [36] found that pressure drop increases with the addition of TiO2 gradually in base refrigerant. Trisaksri and Wongwises [37] reported that increasing the particle volume fraction decreased the boiling heat transition rate and adding TiO2 particles in base refrigerant R141b deteriorated the heat flow. Bobbo et al. [38] experimentally investigated a study in order to define the effect of TiO2/carbon nanohorns (SWCNH) dispersion on the tribology of compressor polyester oil (SW32). The author reported better performance of TiO2/SW32 blend compared to pure SW32 and SW32/SWCNH mixtures. Bi et al. [39] dispersed TiO2 nanoparticles in R600a refrigerant through compressor lubricant and observed significant increment in freezing capacity about 9.60% by reducing energy consumption up to 5.94% using 0.1 and 0.5 g/L TiO2 nanoparticle. Sabareesh et al. [40] used 0.05–0.015 vol% TiO2 nanoparticles in compressor lubricant and observed that 0.01 vol% is optimum fraction value for better tribological properties. The author reported 17% improvement in COP and 11% reduction compressor energy consumption using nanoparticles with R12. Adelekan et al. [41] observed better COP in refrigerant cycle using TiO2/MO nanolubricant instead of R134a/MO.

2.4 Studies related to CNTs and other nanoparticles

Jiang et al. [42] reported 50–104% increment in thermal conductivity with distinct particle fractions and diameters of CNTs dispersed in R113 refrigerant. The author declared 1.0 vol% fraction of CNT as optimum value. Park and Jung [43] performed nucleate boiling heat transfer analysis for CNTs with 1 vol% fraction using R123 and R134a refrigerants. The results found that heat transfer rate was improved (up to 36.6%) at low heat fluxes while it starts decreases at large heat fluxes. Peng et al. [44] reported 61% improvement in heat transfer coefficient with CNTs dispersed in R113/oil blend. Moreover, the author found that higher length and smaller outer diameter increased the heat transfer coefficient. Jiang et al. [42] conducted an experimental study on carbon nanotubes (CNTs) based nanofluids and proposed a modified Yu-Choi model which defined a decent deviation about 5.5% from the experimental result. Henderson et al. [45] used SiO2 particles in polyester oil and reported 55% reduction in flow boiling performance due to the difficulties in nanolubricant dispersion and stability. Whereas, using Al2O3/POE nanolubricant results the great heat transfer improvement.

Kumar and Singh [46] reported 7.48% less energy consumption and 48% higher COP with 1.0 wt% of ZnO nanoparticles dispersed in R290/R600a/MO blend. Peng et al. [47] dispersed diamond nanoparticles in R113/VG68 blend to study nucleate boiling heat transfer coefficient. The author reported 63.4% enhancement in HTC using 0.05–0.5 wt% of nanoparticles fractions. Moreover, the study was compared with CuO/oil blend and found that diamond nanoparticles have higher impact on heat transfer characteristics. Kedzierski [48] reported 98% improvement in boiling heat transfer with 0.5%, 1% and 2% mass fractions of diamond nanoparticles dispersed in R134a. Naphon et al. [49] concentrated on the effect of Ti nanoparticles on the efficiency of copper heat pipe using R11 as base refrigerant. The study reported 0.01% nanoparticle fraction give highest efficiency ratio. Wang et al. [50] used a new category of nano oil which is created by mixing NiFe2O4 nanoparticles into naphthene-based oil B32 as an alternate to polyester VG32 and observed 6% improvement in overall COP.


3. Conclusions and future work

In present chapter, the studies of the previous findings on the heat transition characteristics, solubility and system performance of vapor compression refrigeration cycle has been presented. The literature related to pool boiling heat transfer enhancement of refrigerants and rheological behavior of lubricants using nanoparticles critically reviewed. The use of nanorefrigerants were improved the heat transfer performance of VCR system especially in nucleate and pool boiling heat transfer. CNTs can be considered as a best candidate for heat transfer enhancement of base refrigerants in comparison with the other nanoparticles. The heat transfer rate increases with decreases nanoparticle dimension while the pressure drop decreases with decreases nanoparticles dimension.

The nanolubricants have great tribology characteristics in terms of wear rate and friction reduction in comparison with base lubricants. TiO2 and CuO are best nanoparticles especially in improvement in tribology characteristics of compressor. It is reported that COP and freezing speed in cooling cycles is increased through application of nanoparticles in base refrigerants. It is found that improvement in VCR system parameters strongly depends on nanoparticle concentration. Thus, optimum value of particle fraction must be defined for better and stable results.

Furthermore, the below mentioned suggestions can be considering in future works:

  1. As the nanoparticles concentration has great effect on thermophysical and tribology properties of refrigerants/lubricants, the study is needed to find the optimum nanorefrigerants and nanolubricants from the perspective of particle size, shapes and flow conditions.

  2. The study on analytical models for the prediction of physical properties is so limited. Future works are needed to viral this study.

  3. The study on condensation and evaporation flow of nanorefrigerants is very limited. It needs to elaborate.

  4. There are no studies available related to effect of nanoparticles on new blend refrigerants such as R1234f.

  5. The studies on the use of nanoparticles with natural refrigerants such as NH3 and CO2 not performed.

  6. As per literature survey, several studies have been done on positive behavior of nanoparticles on heat transfer enhancement of refrigerants. The studies related to effect of nanoparticles on basic physical phenomena are somewhere missing.

  7. There are no studies available on the flow of nanorefrigerants inside the microchannels and corrugated tubes.


  1. 1. Wang RX, Hao B, Xie GZ. A refrigerating system using HFC134a and mineral lubricant appended with n TiO2 as working fluids. In: Proceedings of the 4th International Symposium on HAVC; Beijing, China: Tsinghua University Press; 2003. pp. 888-892
  2. 2. Azmi WH, Sharma KV, Sarma PK, Mamat R, Najafi G. Heat transfer and friction factor of water based TiO2 and SiO2 nanofluids under turbulent flow in a tube. International Communications in Heat and Mass Transfer. 2014;59:30-38
  3. 3. Hamid KA, Azmi WH, Mamat R, Usri NA, Najafi G. Effect of temperature on heat transfer coefficient of titanium dioxide in ethylene glycol-based nanofluid. Journal of Mechanical Engineering Science. 2015;8:1367-1375
  4. 4. Alawi OA, Sidik NAC. Applications of nanorefrigerant and nanolubricants in refrigeration, air-conditioning and heat pump systems: A review. International Communication of Heat Mass Transfer. 2015;68:91-97
  5. 5. Alawi OA, Sidik NAC, Mohammed H. A comprehensive review of fundamentals, preparation and applications of nanorefrigerants. International Communications in Heat and Mass Transfer. 2014;54:81-95
  6. 6. Azmi WH, Sharif MZ, Yusof TM, Mamat R, Redhwan AAM. Potential of nanorefrigerant and nanolubricant on energy saving in refrigeration system—A review. Renewable and Sustainable Energy Reviews. 2017;69:415-428
  7. 7. Redhwan AAM, Azmi WH, Sharif MZ, Zawawi NNM. Thermal conductivity enhancement of Al2O3 and SiO2 nanolubricants for application in automotive air conditioning (AAC) system. In: MATEC Web of Conferences; Vol. 90. 2016. p. 01051
  8. 8. Jwo CS, Jeng LY, Teng TP, Chang H. Effects of nanolubricant on performance of hydrocarbon refrigerant system. Journal of Vacuum Science and Technology B: Microelectronics and Nanometer Structures Processing. 2009;27(3):1473-1477
  9. 9. Mahbubul IM, Saidur R, Amalina MA. Thermal conductivity, viscosity and density of R141b refrigerant based nanofluid. Procedia Engineering. 2013;56:310-315
  10. 10. Mahbubul IM, Saidur R, Amalina MA. Heat transfer and pressure drop characteristics of Al2O3-R141b nanorefrigerant in horizontal smooth circular tube. Procedia Engineering. 2013;56:323-329
  11. 11. Mahbubul IM, Fadhilah SA, Saidur R, Leong KY, Amalina MA. Thermophysical properties and heat transfer performance of Al2O3/R-134a nanorefrigerants. International Journal of Heat and Mass Transfer. 2013;57:100-108
  12. 12. Peng H, Ding G, Jiang W, Hu H, Gao Y. Measurement and correlation of frictional pressure drop of refrigerant-based nanofluid flow boiling inside a horizontal smooth tube. International Journal of Refrigeration. 2009;32:1756-1764
  13. 13. Sun B, Yang D. Experimental study on the heat transfer characteristics of nanorefrigerants in an internal thread copper tube. International Journal of Heat and Mass Transfer. 2013;64:559-566
  14. 14. Kedzierski MA. Viscosity and density of aluminum oxide nanolubricant. International Journal of Refrigeration. 2013;36:1333-1340
  15. 15. Kedzierski MA. R134a/Al2O3 nanolubricant mixture pool boiling on a rectangular finned surface. Journal of Heat Transfer. 2012;134:12-15
  16. 16. Tang X, Zhao YH, Diao YH. Experimental investigation of the nucleate pool boiling heat transfercharacteristics of δ-Al2O3-R141b nanofluids on a horizontal plate. Experimental Thermal and Fluid Science. 2014;52:88-96
  17. 17. Mahbubul IM, Saidur R, Amalina MA. Influence of particle concentration and temperature on thermal conductivity and viscosity of Al2O3/R141b nanorefrigerant. International Communications in Heat and Mass Transfer. 2013;(43):100-104
  18. 18. Kumar DS, Elansezhian RD. Experimental study on Al2O3-R134a nanorefrigerant in refrigeration system. International Journal of Modern Engineering Research. 2012;2(5):3927-3929
  19. 19. Subramani N, Prakash MJ. Experimental studies on a vapour compression system using. International Journal of Engineering, Science and Technology. 2011;3(9):95-102
  20. 20. Yusof TM, Arshad AM, Suziyana MD, Chui LG, Basrawi MF. Experimental study of a domestic refrigerator with POE-Al2O3 nanolubricant. International Journal of Mechanical Engineering and Technology. 2015;11:2243-2252
  21. 21. Cremaschi L, Wong T, Bigi AAM. Thermodynamic and heat transfer properties of Al2O3 nanolubricants. In: International Refrigeration and Air Conditioning Conference; Purdue: Purdue E-Pubs; 2014. pp. 1-10
  22. 22. Kedzierski MA, Gong M. Effect of CuO nanolubricant on R134a pool boiling heat transfer. International Journal of Refrigeration. 2009;32:791-799
  23. 23. Kedzierski MA. Effect of CuO nanoparticle concentration on R134a/lubricant pool boiling heat transfer. Journal of Heat Transfer. 2009;131:043205
  24. 24. Bartelt K, Park Y, Liu L, Jacobi A. Flow-boiling of R-134a/POE/CuO nanofluids in a horizontal tube. In: International Refrigeration and Air Conditioning Conference; Indiana: West Lafayette; 2008
  25. 25. Peng H, Ding G, Jiang W, Hu H, Gao Y. Heat transfer characteristics of refrigerant-based nanofluid flow boiling inside a horizontal smooth tube. International Journal of Refrigeration. 2009;32:1259-1270
  26. 26. Henderson K, Park Y, Liu L, Jacobi AM. Flow-boiling heat transfer of R-134abased nanofluids in a horizontal tube. International Journal of Heat and Mass Transfer. 2010;53:944-951
  27. 27. Kedzierski MA, Gong M. Effect of CuO Nanolubricant on R134a Pool Boiling Heat Transfer with Extensive Measurement and Analysis Details. USA: US Department of Commerce, National Institute of Standards and Technology; 2007
  28. 28. Bartelt K, Park Y, Liu L, Jacobi A. Flow-boiling of R-134a/POE/CuO nanofluids in a horizontal tube. In: International Refrigeration and Air Conditioning Conference; Purdue: Purdue e-Pubs; 2008. pp. 1-8
  29. 29. Kumar R, Singh J, Kundal P. Effect of CuO nanolubricant on compressor characteristics and performance of LPG based refrigeration cycle: Experimental investigation. Heat and Mass Transfer. 2018;54(5):1405-1413
  30. 30. Abdel-Hadi EA, Taher SH, Torki AHM, Hamad SS. Heat transfer analysis of vapor compression system using nano CuO-R134a. In: International Conference on Advanced Materials Engineering IPCSIT; Vol. 15. 2011. pp. 80-84
  31. 31. Peng H, Ding G, Hu H, Jiang W. Effect of nanoparticle size on nucleate pool boiling heat transfer of refrigerant/oil mixture with nanoparticles. International Journal of Heat and Mass Transfer. 2011;54:1839-1850
  32. 32. Akhavan-Behabadi MA, Sadoughi MK, Darzi M, Fakoor-Pakdaman M. Experimental study on heat transfer characteristics of R600a/POE/CuO nano-refrigerant flow condensation. Experimental Thermal and Fluid Science. 2015;66:46-52
  33. 33. Jiang W-T, Ding G-L, Wang K-J. Calculation of the conductivity of nanorefrigerant based on particles aggregation theory. Journal of Shanghai Jiaotong University. 2006;8:1-3
  34. 34. Li P, Wu X, Li H, Wang W. Investigation of pool boiling heat transfer of R11 with TiO2 nano-particles. Journal of Engineering Thermophysics. 2008;29(1):124
  35. 35. Trisaksri V, Wongwises S. Nucleate pool boiling heat transfer of TiO2-R141b. International Communications in Heat and Mass Transfer. 2018;92:56-63
  36. 36. Mahbubul IM, Saidur R, Amalina MA. Pressure drop characteristics of TiO2-R123 nanorefrigerant in a circular tube. Engineering Transactions. 2011;6:124-130
  37. 37. Trisaksri V, Wongwises S. Nucleate pool boiling heat transfer of TiO2-R141b nanofluids. International Journal of Heat and Mass Transfer. 2009;52:1582-1588
  38. 38. Bobbo S, Fedele L, Fabrizio M, Barison S, Battiston S, Pagura C. Influence of nanoparticles dispersion in POE oils on lubricity and R134a solubility. International Journal of Refrigeration. 2010;33:1180-1186
  39. 39. Bi S, Guo K, Liu Z, Wu J. Performance of a domestic refrigerator using TiO2-R600a nano-refrigerant as working fluid. Energy Conversion and Management. 2011;52:733-737
  40. 40. Sabareesh RK, Gobinath N, Sajith V, Das S, Sobhan CB. Application of TiO2 nanoparticles as a lubricant-additive for vapor compression refrigeration systems—An experimental investigation. International Journal of Refrigeration. 2012;35:1989-1996
  41. 41. Adelekan DS, Ohunakin OS, Babarinde TO, Odunfa MK, Leramo RO, Oyedepo SO, et al. Experimental performance of LPG refrigerant charges with varied concentration of TiO2 nano-lubricants in a domestic refrigerator. Case Studies in Thermal Engineering. 2017;9:55-61
  42. 42. Jiang W, Ding G, Peng H. Measurement and model on thermal conductivities of carbon nanotube nanorefrigerants. International Journal of Thermal Sciences. 2009;48:1108-1115
  43. 43. Park KJ, Jung D. Boiling heat transfer enhancement with carbon nanotubes for refrigerants used in building air-conditioning. Energy and Buildings. 2007;38:1061-1064
  44. 44. Peng H, Ding G, Hu H, Jiang W. Influence of carbon nanotubes on nucleate pool boiling heat transfer characteristics of refrigerant-oil mixture. International Journal of Thermal Sciences. 2010;49:2428-2438
  45. 45. Henderson K, Park YG, Liu L, Jacobi AM. Flow-boiling heat transfer of R-134a-based nanofluids in a horizontal tube. International Journal of Heat and Mass Transfer. 2010;53(5-6):944-951
  46. 46. Kumar R, Singh J. Effect of ZnO nanoparticles in R290/R600a (50/50) based vapour compression refrigeration system added via lubricant oil on compressor suction and discharge characteristics. Heat and Mass Transfer. 2017;53(5):1579-1587
  47. 47. Peng H, Ding G, Hu H, Jiang W, Zhuang D, Wang K. Nucleate pool boiling heat transfer characteristics of refrigerant/oil mixture with diamond nanoparticles. International Journal of Refrigeration. 2010;33:347-358
  48. 48. Kedzierski MA. Effect of diamond nanolubricant on R134a pool boiling heat transfer. Journal of Heat Transfer. 2012;134:051001
  49. 49. Naphon P, Thongkum D, Assadamongkol P. Heat pipe efficiency enhancement with refrigerant–nanoparticles mixtures. Energy Conversion and Management. 2009;50:772-776
  50. 50. Wang R, Wu Q, Wu Y. Use of nanoparticles to make mineral oil lubricants feasible for use in a residential air conditioner employing hydro-fluorocarbons refrigerants. Energy and Buildings. 2010;42:2111-2117

Written By

Ravinder Kumar

Submitted: July 17th, 2019 Reviewed: August 19th, 2019 Published: November 27th, 2019