Experimental study on heat transfer characteristics of R600a/POE/CuO nano-refrigerant flow condensation

Akhavan-Behabadi, M.A.; Sadoughi, Mohammadkazem; Darzi, Milad; Fakoor-Pakdaman, M.

doi:10.1016/j.expthermflusci.2015.02.027

Cited by 95 publications

(9 citation statements)

References 21 publications

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“…9 that the new model [Eq. (11)] predicts more than 90% of the data obtained for the pure refrigerant inside the flattened tubes with an error band of 20%.…”

Section: Heat Transfer Coefficient Inside the Flattened Tubesmentioning

confidence: 99%

“…Studies on nanorefrigerants indicated that mixing proper mass fraction of nanoparticles and refrigerant caused significant enhancement in the convective heat transfer coefficient [7][8][9][10][11]. Most of the available literature on 1) pool boiling [12,13], and 2) boiling [14,15] heat transfer characteristics of nanorefrigerants is limited to round tubes.…”

Section: Introductionmentioning

confidence: 99%

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Simultaneous Effects of Flattening Tube and Adding Nanoparticles on Boiling Heat Transfer

Akhavan-Behabadi

Sadoughi

Darzi

et al. 2017

Journal of Thermophysics and Heat Transfer

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An empirical investigation is performed on boiling heat transfer characteristics of R600a refrigerant flow inside horizontal flattened tubes. Round copper tubes of 8.7 mm inner diameter are deformed into flattened shapes with different internal heights of 6.9, 5.5, and 3.4 mm as the test sections. Effects of different parameters such as mass flux, vapor quality, and internal tube height on the heat transfer coefficient are studied. It is shown that flattening the tube causes significant heat transfer enhancement. The maximum augmentation ratio of 163% is obtained for the flattened tube with the maximum aspect ratio of 3.56. A new correlation is developed based on the obtained experimental data to predict the heat transfer coefficient in flattened tubes; 90% of the acquired data are predicted within. Consequently, the tested flattened tube with maximum heat transfer rate is selected to study the effects of nanoparticles. Experiments are conducted for three different working fluid types including 1) pure refrigerant (R600a); 2) refrigerant/lubricant (R600a/oil); and 3) nanorefrigerant: refrigerant/lubricant/nanoparticles (R600a/oil/CuO). Polyolester oil is used as the lubricant in the two latter cases. In addition, nanorefrigerants (R600a/oil/CuO) are prepared by dispersing CuO nanoparticles with different mass fractions of 0.5, 1, and 1.5% in the baseline mixture (R600a/oil). Thereby, maximum heat transfer enhancement of 79% is achieved compared to the pure refrigerant case. The results of this study provide the platform for designing compact efficient heat exchangers/heat sinks for the emerging thermal engineering applications under high thermal load conditions. NomenclatureA = area, m 2 D = diameter, m D e = equivalent diameter, m D h = hydraulic diameter, m G = mass flux, kg∕m 2 · s H = channel height, m e = enthalpy, J∕kg h = heat transfer coefficient, kW∕m 2 · K K = thermal conductivity, kW∕m 2 · K L = length, m m = mass flow rate, kg∕s Q pre = preheater heat transfer rate, W Q test = evaporator heat transfer rate, W W = channel width, m x = quality ω = mass fraction Subscripts f = flat in = inlet l = liquid loc = local concentration no = nominal concentration o = oil out = outlet R = refrigerant s = surface Th = thermocouple v = vapor wall = tube wall

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“…9 that the new model [Eq. (11)] predicts more than 90% of the data obtained for the pure refrigerant inside the flattened tubes with an error band of 20%.…”

Section: Heat Transfer Coefficient Inside the Flattened Tubesmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Simultaneous Effects of Flattening Tube and Adding Nanoparticles on Boiling Heat Transfer

Akhavan-Behabadi

Sadoughi

Darzi

et al. 2017

Journal of Thermophysics and Heat Transfer

Self Cite

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show abstract

“…The experiments with oil in the refrigerant loop (refrigerant/lubricant mixture) at various concentrations. For example, Akhavan-Behabadi et al [88] utilized polyolester oil (POE) as the lubricant in R600a/POE mixture to study experimentally the heat transfer characteristics of flow condensation.…”

Section: Kim Andmentioning

confidence: 99%

“…The experiments with new types of working fluids such as refrigerant/lubricant/nanoparticles mixture. For example, Akhavan-Behabadi et al [88] used R600a/ polyolester oil (POE)/CuO nano-refrigerant to study experimentally the heat transfer characteristics of flow condensation. Nano-refrigerant is a type of nanofluid where a refrigerant is used as the base fluid [89].…”

Section: Kim Andmentioning

confidence: 99%

A Critical Review on Condensation Pressure Drop in Microchannels and Minichannels

Awad¹,

Dalkılıç²

2015

Heat Transfer Studies and Applications

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“…These successes boarder on improved system COP, reduced power consumption and better heat transfer between the working fluid and the air that requires cooling. Some of these works are those by Subramani and Prakash (2011), Yang et al (2015, Akhavan-Behabadi et al (2015), Bi et al (2011), Yang et al (2012 and Coumaressin and Palaniradja (2014). Apart from nanorefrigerants, nanolubricants can be used to increase thermal dissipation, reduce wear and mitigate some extreme pressure characteristics of compressors lubricants as seen from the works of Subramani and Prakash (2011) and Subramani et al (2013).…”

Section: Introductionmentioning

confidence: 99%

Regulation of Nanorefrigerant Use: A Proactive Measure Against Possible Undesirable Health and Environmental Implications

Ogueke

Emekwuru

2017

European Journal of Sustainable Development Research

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Recent research studies have shown the very high potentials nanotechnology application has in the refrigeration and air conditioning industry for improving the thermophysical properties of refrigerants and lubricants hence leading to systems with higher COP and much reduced size. The successes achieved with nanorefrigerants are connected to the improved technology for the preparation of nanofluids that has led to achieving more homogeneous and stable mixture of the base fluid and nanoparticle. However, available literatures point to the fact that nanoparticles can find its way into the human cells and as such is a potential health risk for humans and animals. At present, emphasis appears to concentrate more on the technological successes achieved with nanorefrigerants, like improved thermal conductivity, nucleate boiling and boiling heat transfer coefficient without factoring in much the potential health implications of adopting it. This paper therefore looked at the potential health consequences of adopting nanotechnology and called for an early regulatory framework to guard against any unforeseen health issues. Areas of future research were also suggested.

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Experimental study on heat transfer characteristics of R600a/POE/CuO nano-refrigerant flow condensation

Cited by 95 publications

References 21 publications

Simultaneous Effects of Flattening Tube and Adding Nanoparticles on Boiling Heat Transfer

Simultaneous Effects of Flattening Tube and Adding Nanoparticles on Boiling Heat Transfer

A Critical Review on Condensation Pressure Drop in Microchannels and Minichannels

Regulation of Nanorefrigerant Use: A Proactive Measure Against Possible Undesirable Health and Environmental Implications

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