A covalent functionalization approach was utilized for the preparation of highly dispersed pentae... more A covalent functionalization approach was utilized for the preparation of highly dispersed pentaethylene glycol-thermally treated graphene-water as the absorbing material inside a flat-plate solar collector. Four mass fractions of nanofluids were prepared (0.025, 0.05, 0.075, and 0.1 wt% pentaethylene glycol-thermally treated graphene-water). Graphene nanoparticles were characterized by energy dispersive X-ray analysis with a scanning electron microscope. Measurements of the thermophysical properties were subsequently carried out for the nanosuspensions. The raw investigation data were collected from an indoor flat-plate solar collector test setup. The experimental procedure included different sets of variables such as input temperatures of 303, 313, and 323 K; fluid mass flow rate of 0.00833, 0.01667, and 0.025 kg s À1 ; and heat flow density of 500, 750, and 1000 W m À2. The thermophysical tests of pentaethylene glycol-thermally treated graphene-water nanofluids showed a proportional increase against weight concentrations, while the specific heat power was reduced. The tests showed an increment in energy efficiency by increasing the fluid mass flow rate and heat input. By comparison, the thermal efficiency decreased with the increasing temperature of the fluid supply. Relative to the base fluid, the energy efficiency of pentaethylene glycol-thermally treated graphene/water-based flat-plate solar collector increased to 10.6%, 11%, and 13.1% at the three fluid mass flow rates. In conclusion, an exponential form was used to derive the thermal effectiveness of flat-plate solar collector based on the experimental data.
In the attempt of preparing multi-walled carbon nanotube (MWCNTs), covalent functionalisation (CF... more In the attempt of preparing multi-walled carbon nanotube (MWCNTs), covalent functionalisation (CF-MWCNTs) were applied. The stable thermal conductivity was measured as a function of temperature. A number of techniques, such as FTIR, FESEM and UV-vis spectrophotometer were employed to characterise both dispersion stability and morphology of functionalised materials. By using ultrasonic test time, the highest stability of nanofluids was achieved at 60 minutes. As a result, the thermal conductivity displayed by CF-MWCNTs was higher than distilled water. In conclusion, improvement in thermal conductivity and stability displayed by CF-MWCNTs was higher, while the best thermal conductivity improvement was recorded at 31%.
IOP Conference Series: Materials Science and Engineering, 2020
In this paper, the thermal stability and specific heat capacities of four imidazolium based ionic... more In this paper, the thermal stability and specific heat capacities of four imidazolium based ionic liquids namely 1-ethyl-3-methyl imidazolium octylsulfate, 1-ethyl-3-methylimidazolium diethyl phosphate, 1,3-dimethyl-imidazolium dimethyl phosphate and 1-butyl-3-methylimidazolium chloride have been experimentally analysed using Thermogravimetric Analysis (TGA) and Differential Scanning Calorimetry (DSC). The thermal stability was assessed by conventional and high resolution modulated TGA with the temperature range of 0 to 700 °C. The specific heat capacity was measured by using DSC within the temperature interval of 0 to 200 °C. The factors influencing the thermal stability and heat capacity of ionic liquids were studied. The thermal analysis results indicate that 1-ethyl-3-methylimidazolium octylsulfate exhibited excellent thermal stability even at 440 °C while 1-ethyl-3-methylimidazolium diethyl phosphate obtained a maximum specific heat capacity of 4.52 J/g.K.
Microstructural Analysis plays an important role in enhancing the mechanical properties of metals... more Microstructural Analysis plays an important role in enhancing the mechanical properties of metals and composites. Usually Aluminium Silicon Carbide (Al6063/SiC) alloys are mixed with strontium, sodium and antimony for high durability even though they are toxic and costly. As an alternative calcium is used as an alloying element to improve the mechanical property of Al6063/Sic alloy. In this paper Al6063 is chosen as the matrix material while Sic is used as a reinforcement where calcium powder is added to modify the silicon phase of the composite. Finally, concentration of Silicon carbide is varied from 0 to 150 mg to produce four specimens of Al6063 alloy and it is subjected to microstructure analysis which showed the reduction of grain size and therefore improvement in the hardness from 52.9 HV to 58.4 HV and decrease in the wear loss from 3.97 to 3.27 percentage.
Predictions are reported for mixed convection using various types of nanofluids over forward-faci... more Predictions are reported for mixed convection using various types of nanofluids over forward-facing double steps in a duct. The continuity, momentum and energy equations are discretized and the simple algorithm is applied to link the pressure and flow fields inside the domain. Different types of nanoparticles Al2O3, CuO, SiO2 and ZnO, with different volume fractions in range of 1-4% are investigated to identify their effects on the heat transfer and fluid characteristics. Numerical investigations are conducted using finite volume method. The results indicate that SiO2-water has the highest Nusselt number followed by Al2O3-water, CuO-water and ZnO-water. The Nusselt number increases as the volume fraction increases but decreases as the nanoparticles diameter increases.
Journal of Nanotechnology in Engineering and Medicine, 2014
Numerical simulations of two-dimensional (2D) laminar mixed convection heat transfer and nanoflui... more Numerical simulations of two-dimensional (2D) laminar mixed convection heat transfer and nanofluids flows over forward facing step (FFS) in a vertical channel are numerically carried out. The continuity, momentum, and energy equations were solved by means of a finite volume method (FVM). The wall downstream of the step was maintained at a uniform wall heat flux, while the straight wall that forms the other side of the channel was maintained at constant temperature equivalent to the inlet fluid temperature. The upstream walls for the FFS were considered as adiabatic surfaces. The buoyancy assisting and buoyancy opposing flow conditions are investigated. Four different types of nanoparticles, Al2O3, CuO, SiO2, and ZnO with different volumes' fractions in the range of 1–4% and different nanoparticle diameters in the range of 25–80 nm, are dispersed in the base fluid (water) are used. In this study, several parameters, such as different Reynolds numbers in the range of 100 < Re &...
This study focuses on the thermal and rheological properties of a hybrid fluid consisting of Tita... more This study focuses on the thermal and rheological properties of a hybrid fluid consisting of Titanium Dioxide/ Chemically functionalized Multi-Walled Carbon Nanotubes (TiO 2 / CF-MWCNTs) suspended in distilled water (DW) for use in flat plate solar collectors applications. The optimal hybridization ratio of CF-MWCNTs: TiO 2 was 40:60. To evaluate thermal efficiency, solar collector tests were conducted using varying flow rates &quot;2LPM, 3LPM, and 4 LPM&quot; according to the ASHRAE&#39;93-2010&#39; principle. The study examined the effects of various weight percentages of TiO 2 /CF-MWCNTs add up to the DW as working base fluid to determine the optimal concentration for enhancing the performance of the &quot;FPSC&quot; efficiency. The experimental results showed that using TiO 2 /CF-MWCNTs in the working fluid improved the collector energy efficiency by approximately 9% and 26% at low and high temperature differences, respectively, compared to distilled water (DW). The effectiveness of the composed nanoadditives was valuation through using various morphological analysis techniques, including Ultraviolet-visible spectroscopy (UV-vis), X-ray diffraction, Field emission scanning electron microscopy (FE-SEM), and high-resolution transmission electron microscopy (HR-TEM). The study found that the rating of the performance index &quot;PI&quot; were totally greater than &quot;1&quot; and increased as the weight concentration of TiO 2 /CF-MWCNTs increased up to 1.10 for 0.1 wt% with a flow rate of 4 LPM, indicating a higher positive effect on energy efficiency than negative effects on pressure drop. The findings revealed that by incorporating only &quot;0.1 wt%&quot; of TiO 2 /CF-MWCNTs and using a flow rate of 4 LPM, the optimal conditions were achieved, resulted in a remarkable improvement in flat plate solar collector (FPSC) efficiency up to 84%. In comparison to the conventional working fluid employed in FPSC, the results demonstrated a significant improvement. 1. Introduction 1.1. Research background and motivation Developing of a clean and renewable energy system as an alternative
In the original publication of the article, the third author's affiliation was tagged incorrectly... more In the original publication of the article, the third author's affiliation was tagged incorrectly as 3 instead of 1. The affiliations 4 to 8 were mentioned incorrectly. The corrected affiliations were given below. The original article has been corrected. Publisher's Note Springer Nature remains neutral with regard to jurisdictional claims in published maps and institutional affiliations.
Covalent and non-covalent nanofluids were tested inside a circular tube fitted with twisted tape ... more Covalent and non-covalent nanofluids were tested inside a circular tube fitted with twisted tape inserts with 45° and 90° helix angles. Reynolds number was 7000 ≤ Re ≤ 17,000, and thermophysical properties were assessed at 308 K. The physical model was solved numerically via a two-equation eddy-viscosity model (SST k-omega turbulence). GNPs-SDBS@DW and GNPs-COOH@DW nanofluids with concentrations (0.025 wt.%, 0.05 wt.% and 0.1 wt.%) were considered in this study. The twisted pipes' walls were heated under a constant temperature of 330 K. The current study considered six parameters: outlet temperature, heat transfer coefficient, average Nusselt number, friction factor, pressure loss, and performance evaluation criterion. In both cases (45° and 90° helix angles), GNPs-SDBS@DW nanofluids presented higher thermohydraulic performance than GNPs-COOH@DW and increased by increasing the mass fractions such as 1.17 for 0.025 wt.%, 1.19 for 0.05 wt.% and 1.26 for 0.1 wt.%. Meanwhile, in bot...
Numerical studies were performed to estimate the heat transfer and hydrodynamic properties of a f... more Numerical studies were performed to estimate the heat transfer and hydrodynamic properties of a forced convection turbulent flow using three-dimensional horizontal concentric annuli. This paper applied the standard k–ε turbulence model for the flow range 1 × 104 ≤ Re ≥ 24 × 103. A wide range of parameters like different nanomaterials (Al2O3, CuO, SiO2 and ZnO), different particle nanoshapes (spherical, cylindrical, blades, platelets and bricks), different heat flux ratio (HFR) (0, 0.5, 1 and 2) and different aspect ratios (AR) (1.5, 2, 2.5 and 3) were examined. Also, the effect of inner cylinder rotation was discussed. An experiment was conducted out using a field-emission scanning electron microscope (FE-SEM) to characterize metallic oxides in spherical morphologies. Nano-platelet particles showed the best enhancements in heat transfer properties, followed by nano-cylinders, nano-bricks, nano-blades, and nano-spheres. The maximum heat transfer enhancement was found in SiO2, followe...
Covalent functionalization (CF-GNPs) and non-covalent functionalization (NCF-GNPs) approaches wer... more Covalent functionalization (CF-GNPs) and non-covalent functionalization (NCF-GNPs) approaches were applied to prepare graphene nanoplatelets (GNPs).
Predictions are reported for mixed convection using various types of nanofluids over forward-faci... more Predictions are reported for mixed convection using various types of nanofluids over forward-facing double steps in a duct. The continuity, momentum and energy equations are discretized and the simple algorithm is applied to link the pressure and flow fields inside the domain. Different types of nanoparticles Al2O3, CuO, SiO2 and ZnO, with different volume fractions in range of 1-4% and different nanoparticles diameter in the range of 20-80nm in base fluid (water) were used. Numerical investigations are conducted using finite volume method. In this study, different parameters such as the geometrical specifications (different steps heights in the range of h1= 0.01m-0.04m and h2 = 0.03m-0.06m for FFS) are used. Different Reynolds numbers in the range of 50-2000 (laminar flow) are investigated to identify their effects on the heat transfer and fluid characteristics. The results indicate that SiO2-water has the highest Nusselt number followed by-water,-water and ZnO-water. The Nusselt number increases as the volume fraction increases but it decreases as the nanoparticles diameter increases. The velocity magnitude increases as the density of nanofluids decreases. The recirculation region and the Nusselt number increase as the step height, Reynolds number, and the volume fraction increase.
International Communications in Heat and Mass Transfer, 2016
Solar energy, which comes first among renewable energy sources, enables efficient use of energy w... more Solar energy, which comes first among renewable energy sources, enables efficient use of energy with many applications due to its low operating cost and environmental friendliness. In this study, we experimentally investigated the effects on thermal efficiency of nanofluid and water as working fluids in flat-plate solar collector hot water solar energy systems. Nanofluids were prepared by adding AI2O3, CuO, and TiCte nanoparticles at 0.2, 0.4, and 0.8 vol. % into distilled water, and then the thermophysical properties (thermal conductivity, viscosity) of the prepared nanofluids were determined. Flow rate was adjusted to 250 1/h at given concentrations for each nanofluid in the experimental setups and data such as collector inlet and outlet temperatures, ambient and tap water temperatures; radiation, humidity, and wind speed were measured and recorded. The obtained data were used to calculate efficiencies according to ASHRAE 93-2003 standards. When compared with water, the results indicated that the use of nanofluid increased collector efficiency.
A covalent functionalization approach was utilized for the preparation of highly dispersed pentae... more A covalent functionalization approach was utilized for the preparation of highly dispersed pentaethylene glycol-thermally treated graphene-water as the absorbing material inside a flat-plate solar collector. Four mass fractions of nanofluids were prepared (0.025, 0.05, 0.075, and 0.1 wt% pentaethylene glycol-thermally treated graphene-water). Graphene nanoparticles were characterized by energy dispersive X-ray analysis with a scanning electron microscope. Measurements of the thermophysical properties were subsequently carried out for the nanosuspensions. The raw investigation data were collected from an indoor flat-plate solar collector test setup. The experimental procedure included different sets of variables such as input temperatures of 303, 313, and 323 K; fluid mass flow rate of 0.00833, 0.01667, and 0.025 kg s À1 ; and heat flow density of 500, 750, and 1000 W m À2. The thermophysical tests of pentaethylene glycol-thermally treated graphene-water nanofluids showed a proportional increase against weight concentrations, while the specific heat power was reduced. The tests showed an increment in energy efficiency by increasing the fluid mass flow rate and heat input. By comparison, the thermal efficiency decreased with the increasing temperature of the fluid supply. Relative to the base fluid, the energy efficiency of pentaethylene glycol-thermally treated graphene/water-based flat-plate solar collector increased to 10.6%, 11%, and 13.1% at the three fluid mass flow rates. In conclusion, an exponential form was used to derive the thermal effectiveness of flat-plate solar collector based on the experimental data.
In the attempt of preparing multi-walled carbon nanotube (MWCNTs), covalent functionalisation (CF... more In the attempt of preparing multi-walled carbon nanotube (MWCNTs), covalent functionalisation (CF-MWCNTs) were applied. The stable thermal conductivity was measured as a function of temperature. A number of techniques, such as FTIR, FESEM and UV-vis spectrophotometer were employed to characterise both dispersion stability and morphology of functionalised materials. By using ultrasonic test time, the highest stability of nanofluids was achieved at 60 minutes. As a result, the thermal conductivity displayed by CF-MWCNTs was higher than distilled water. In conclusion, improvement in thermal conductivity and stability displayed by CF-MWCNTs was higher, while the best thermal conductivity improvement was recorded at 31%.
IOP Conference Series: Materials Science and Engineering, 2020
In this paper, the thermal stability and specific heat capacities of four imidazolium based ionic... more In this paper, the thermal stability and specific heat capacities of four imidazolium based ionic liquids namely 1-ethyl-3-methyl imidazolium octylsulfate, 1-ethyl-3-methylimidazolium diethyl phosphate, 1,3-dimethyl-imidazolium dimethyl phosphate and 1-butyl-3-methylimidazolium chloride have been experimentally analysed using Thermogravimetric Analysis (TGA) and Differential Scanning Calorimetry (DSC). The thermal stability was assessed by conventional and high resolution modulated TGA with the temperature range of 0 to 700 °C. The specific heat capacity was measured by using DSC within the temperature interval of 0 to 200 °C. The factors influencing the thermal stability and heat capacity of ionic liquids were studied. The thermal analysis results indicate that 1-ethyl-3-methylimidazolium octylsulfate exhibited excellent thermal stability even at 440 °C while 1-ethyl-3-methylimidazolium diethyl phosphate obtained a maximum specific heat capacity of 4.52 J/g.K.
Microstructural Analysis plays an important role in enhancing the mechanical properties of metals... more Microstructural Analysis plays an important role in enhancing the mechanical properties of metals and composites. Usually Aluminium Silicon Carbide (Al6063/SiC) alloys are mixed with strontium, sodium and antimony for high durability even though they are toxic and costly. As an alternative calcium is used as an alloying element to improve the mechanical property of Al6063/Sic alloy. In this paper Al6063 is chosen as the matrix material while Sic is used as a reinforcement where calcium powder is added to modify the silicon phase of the composite. Finally, concentration of Silicon carbide is varied from 0 to 150 mg to produce four specimens of Al6063 alloy and it is subjected to microstructure analysis which showed the reduction of grain size and therefore improvement in the hardness from 52.9 HV to 58.4 HV and decrease in the wear loss from 3.97 to 3.27 percentage.
Predictions are reported for mixed convection using various types of nanofluids over forward-faci... more Predictions are reported for mixed convection using various types of nanofluids over forward-facing double steps in a duct. The continuity, momentum and energy equations are discretized and the simple algorithm is applied to link the pressure and flow fields inside the domain. Different types of nanoparticles Al2O3, CuO, SiO2 and ZnO, with different volume fractions in range of 1-4% are investigated to identify their effects on the heat transfer and fluid characteristics. Numerical investigations are conducted using finite volume method. The results indicate that SiO2-water has the highest Nusselt number followed by Al2O3-water, CuO-water and ZnO-water. The Nusselt number increases as the volume fraction increases but decreases as the nanoparticles diameter increases.
Journal of Nanotechnology in Engineering and Medicine, 2014
Numerical simulations of two-dimensional (2D) laminar mixed convection heat transfer and nanoflui... more Numerical simulations of two-dimensional (2D) laminar mixed convection heat transfer and nanofluids flows over forward facing step (FFS) in a vertical channel are numerically carried out. The continuity, momentum, and energy equations were solved by means of a finite volume method (FVM). The wall downstream of the step was maintained at a uniform wall heat flux, while the straight wall that forms the other side of the channel was maintained at constant temperature equivalent to the inlet fluid temperature. The upstream walls for the FFS were considered as adiabatic surfaces. The buoyancy assisting and buoyancy opposing flow conditions are investigated. Four different types of nanoparticles, Al2O3, CuO, SiO2, and ZnO with different volumes' fractions in the range of 1–4% and different nanoparticle diameters in the range of 25–80 nm, are dispersed in the base fluid (water) are used. In this study, several parameters, such as different Reynolds numbers in the range of 100 < Re &...
This study focuses on the thermal and rheological properties of a hybrid fluid consisting of Tita... more This study focuses on the thermal and rheological properties of a hybrid fluid consisting of Titanium Dioxide/ Chemically functionalized Multi-Walled Carbon Nanotubes (TiO 2 / CF-MWCNTs) suspended in distilled water (DW) for use in flat plate solar collectors applications. The optimal hybridization ratio of CF-MWCNTs: TiO 2 was 40:60. To evaluate thermal efficiency, solar collector tests were conducted using varying flow rates &quot;2LPM, 3LPM, and 4 LPM&quot; according to the ASHRAE&#39;93-2010&#39; principle. The study examined the effects of various weight percentages of TiO 2 /CF-MWCNTs add up to the DW as working base fluid to determine the optimal concentration for enhancing the performance of the &quot;FPSC&quot; efficiency. The experimental results showed that using TiO 2 /CF-MWCNTs in the working fluid improved the collector energy efficiency by approximately 9% and 26% at low and high temperature differences, respectively, compared to distilled water (DW). The effectiveness of the composed nanoadditives was valuation through using various morphological analysis techniques, including Ultraviolet-visible spectroscopy (UV-vis), X-ray diffraction, Field emission scanning electron microscopy (FE-SEM), and high-resolution transmission electron microscopy (HR-TEM). The study found that the rating of the performance index &quot;PI&quot; were totally greater than &quot;1&quot; and increased as the weight concentration of TiO 2 /CF-MWCNTs increased up to 1.10 for 0.1 wt% with a flow rate of 4 LPM, indicating a higher positive effect on energy efficiency than negative effects on pressure drop. The findings revealed that by incorporating only &quot;0.1 wt%&quot; of TiO 2 /CF-MWCNTs and using a flow rate of 4 LPM, the optimal conditions were achieved, resulted in a remarkable improvement in flat plate solar collector (FPSC) efficiency up to 84%. In comparison to the conventional working fluid employed in FPSC, the results demonstrated a significant improvement. 1. Introduction 1.1. Research background and motivation Developing of a clean and renewable energy system as an alternative
In the original publication of the article, the third author's affiliation was tagged incorrectly... more In the original publication of the article, the third author's affiliation was tagged incorrectly as 3 instead of 1. The affiliations 4 to 8 were mentioned incorrectly. The corrected affiliations were given below. The original article has been corrected. Publisher's Note Springer Nature remains neutral with regard to jurisdictional claims in published maps and institutional affiliations.
Covalent and non-covalent nanofluids were tested inside a circular tube fitted with twisted tape ... more Covalent and non-covalent nanofluids were tested inside a circular tube fitted with twisted tape inserts with 45° and 90° helix angles. Reynolds number was 7000 ≤ Re ≤ 17,000, and thermophysical properties were assessed at 308 K. The physical model was solved numerically via a two-equation eddy-viscosity model (SST k-omega turbulence). GNPs-SDBS@DW and GNPs-COOH@DW nanofluids with concentrations (0.025 wt.%, 0.05 wt.% and 0.1 wt.%) were considered in this study. The twisted pipes' walls were heated under a constant temperature of 330 K. The current study considered six parameters: outlet temperature, heat transfer coefficient, average Nusselt number, friction factor, pressure loss, and performance evaluation criterion. In both cases (45° and 90° helix angles), GNPs-SDBS@DW nanofluids presented higher thermohydraulic performance than GNPs-COOH@DW and increased by increasing the mass fractions such as 1.17 for 0.025 wt.%, 1.19 for 0.05 wt.% and 1.26 for 0.1 wt.%. Meanwhile, in bot...
Numerical studies were performed to estimate the heat transfer and hydrodynamic properties of a f... more Numerical studies were performed to estimate the heat transfer and hydrodynamic properties of a forced convection turbulent flow using three-dimensional horizontal concentric annuli. This paper applied the standard k–ε turbulence model for the flow range 1 × 104 ≤ Re ≥ 24 × 103. A wide range of parameters like different nanomaterials (Al2O3, CuO, SiO2 and ZnO), different particle nanoshapes (spherical, cylindrical, blades, platelets and bricks), different heat flux ratio (HFR) (0, 0.5, 1 and 2) and different aspect ratios (AR) (1.5, 2, 2.5 and 3) were examined. Also, the effect of inner cylinder rotation was discussed. An experiment was conducted out using a field-emission scanning electron microscope (FE-SEM) to characterize metallic oxides in spherical morphologies. Nano-platelet particles showed the best enhancements in heat transfer properties, followed by nano-cylinders, nano-bricks, nano-blades, and nano-spheres. The maximum heat transfer enhancement was found in SiO2, followe...
Covalent functionalization (CF-GNPs) and non-covalent functionalization (NCF-GNPs) approaches wer... more Covalent functionalization (CF-GNPs) and non-covalent functionalization (NCF-GNPs) approaches were applied to prepare graphene nanoplatelets (GNPs).
Predictions are reported for mixed convection using various types of nanofluids over forward-faci... more Predictions are reported for mixed convection using various types of nanofluids over forward-facing double steps in a duct. The continuity, momentum and energy equations are discretized and the simple algorithm is applied to link the pressure and flow fields inside the domain. Different types of nanoparticles Al2O3, CuO, SiO2 and ZnO, with different volume fractions in range of 1-4% and different nanoparticles diameter in the range of 20-80nm in base fluid (water) were used. Numerical investigations are conducted using finite volume method. In this study, different parameters such as the geometrical specifications (different steps heights in the range of h1= 0.01m-0.04m and h2 = 0.03m-0.06m for FFS) are used. Different Reynolds numbers in the range of 50-2000 (laminar flow) are investigated to identify their effects on the heat transfer and fluid characteristics. The results indicate that SiO2-water has the highest Nusselt number followed by-water,-water and ZnO-water. The Nusselt number increases as the volume fraction increases but it decreases as the nanoparticles diameter increases. The velocity magnitude increases as the density of nanofluids decreases. The recirculation region and the Nusselt number increase as the step height, Reynolds number, and the volume fraction increase.
International Communications in Heat and Mass Transfer, 2016
Solar energy, which comes first among renewable energy sources, enables efficient use of energy w... more Solar energy, which comes first among renewable energy sources, enables efficient use of energy with many applications due to its low operating cost and environmental friendliness. In this study, we experimentally investigated the effects on thermal efficiency of nanofluid and water as working fluids in flat-plate solar collector hot water solar energy systems. Nanofluids were prepared by adding AI2O3, CuO, and TiCte nanoparticles at 0.2, 0.4, and 0.8 vol. % into distilled water, and then the thermophysical properties (thermal conductivity, viscosity) of the prepared nanofluids were determined. Flow rate was adjusted to 250 1/h at given concentrations for each nanofluid in the experimental setups and data such as collector inlet and outlet temperatures, ambient and tap water temperatures; radiation, humidity, and wind speed were measured and recorded. The obtained data were used to calculate efficiencies according to ASHRAE 93-2003 standards. When compared with water, the results indicated that the use of nanofluid increased collector efficiency.
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