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Nowadays, in many developing countries like India they are facing the shortage of energy. The Refrigeration system has become the major consumer of energy for many industrial as well as household a...

Nowadays due to advancement in nanotechnology, it is possible to prepare nanoparticles, which is very much useful to enhance the thermal properties of heat transfer fluids. A Nanofluid is advanced heat transfer fluid with dispersed nanoparticles in base fluid. This paper is about the experimental study carried out to study the effectiveness of conventional single slope solar still plant (CSP) integrated with parabolic trough collector (PTC) using Nanofluid. Experiments were carried for water and Al2O3/Water nanofluid with 0.05% and 0.1% volume fraction as a working fluid in the integrated system. The results show that pure water yield is remarkably increase using the integrated still plant. It is observed that maximum yield is found 1741 ml with 0.1% volume fraction Al2O3/Water nanofluid as working fluid for 2.5 cm saline water depth in 1 m2 basin. This shows approximately 66% and 70% rise in the yield and thermal efficiency respectively using Al2O3/Water nanofluid integrated solar still system than CSP.

In automobiles, the cooling system is essential in increasing engine performance. Conventional coolants like water and ethylene glycol have low thermal conductivity. Nanotechnology allows the development of a high thermal conductivity coolant named ‘nanocoolant’, a colloidal suspension. This study is focused on the effect of nanocoolant size on the radiator, which is also responsible for fuel consumption. To prepare nanocoolant two-step method was used, in which nanoparticles were prepared separately and dispersed in a base fluid under ultrasonic agitation. This research was carried out for the dispersion of Al2O3 in a water-ethylene glycol mixture with volume concentrations of 0%, 0.2%, 0.4% and 0.6%. The experimentation was carried out on 180, 216, 288 and 360 mm tube-length radiators. The experiments were conducted at a coolant inlet temperature 65 °C, air velocity of 1.05 m/s, and volume rate of 4 to 9 litres per minute. The result shows that using 0.2% Al2O3 nanoparticles, the overall heat transfer coefficient was augmented by 43% more than the base fluid. It is also seen that for 0.6% volume fraction nanocoolant, approximately 65% reduction in frontal radiator area is possible, which leads to decrement in the drag force and pumping power.

In this research, the heat transfer potential of Al2O3/Water-Mono Ethylene Glycol nanofluids is investigated experimentally as a coolant for car radiators. The base fluid was the mixture of water and mono ethylene glycol with 50:50 proportions by volume. The stable nanofluids obtained by ultra-sonication are used in all experiments. In this study nanoparticle volume fraction, coolant flow rate, inlet temperature used in the ranges of 0.2–0.8%, 4–9 l per minute and 65–85 °C. The results show that the heat transfer performance of radiator is enhanced by using nanofluids compared to conventional coolant. Nanofluid with lowest 0.2% volume fraction 30% rise in heat transfer is observed. Also the estimation of reduction in frontal area of radiator if base fluid is replaced by Nanofluid is done which will make lighter cooling system, produce less drag and save the fuel cost.

In this research, the overall heat transfer coefficient of Al2O3/water–mono ethylene glycol (MEG) nanofluids is investigated experimentally in a car radiator under laminar flow conditions. The experimental rig developed is similar to the automotive cooling system. The stable nanofluid used is prepared by a two-step method. Ultrasonication is done for proper dispersion of 20 nm Al2O3 nanoparticle in carrier fluid water and MEG mixture with 50:50 proportions by volume. The experimental study showed that use of a nanofluid enhances the overall heat transfer coefficient as compared to the base fluid. In this study as the nanoparticle volume fraction increases from 0% to 0.8%, the overall heat transfer coefficient also increases. It was observed that as the nanofluid inlet temperature increased from 65 °C to 85 °C, the overall heat transfer coefficient decreased. It was found that using a 0.2% volume fraction Al2O3/water–MEG nanofluid can enable a 36.69 % reduction in surface area of the radiator.

Purpose In the twenty-first century, the use of fossil fuels has increased drastically because the necessity of energy is increasing day by day which affects the world’s economy. The solar energy (photo-thermal energy conversion) system is the most economical and eco-friendly alternative source. To increase the use of domestic as well as commercialization purpose, the authors have reviewed this paper on the solar water heater along with its structural mechanism for energy enhancement and to create easier stair steps for climbing on the green world dream. Design/methodology/approach In this study, nanotechnology has remarkably built its own use for extending thermal efficiency by using some gradual experiments. It is a phenomenon, like nanofluid (as a working fluid for a direct solar collector), nanocoating (on the surface of a solar-evacuated tube by using the chemical vapor deposition/physical vacuum deposition/sol–gel technique) and nanorod-based solar collector tube. Findings This invention gives greater efficiency rather than the conventional systems, but also this advancement is not too much supported in a low- temperature environment also, we can consider the poor light absorption characteristics of the pure water (Bencic, et al., 2000). Originality/value The basic idea and understanding of this phenomenon to improve solar collecting performance for obtaining a high working-fluid temperature are discussed in this paper.

In this communication we report on the optical property of CuO nanoparticles prepared by cost effective, simplistic and environment-friendly sol-gel technique on borosilicate glass by dip coating. The particle size was analyzed by Transmission Electron Microscope (TEM) which depicted particle size of CuO ~ 5 nm. To understand the optical behavior of nanosized CuO particles on borosilicate glass tube UV-visible spectrum has been taken. Effective mass model calculations determined the size of particles as 2.26 nm, which supports the TEM analysis. Samples were also analyzed by Fourier transform infrared spectrum (FT-IR) to understand the chemical bond in detail.

Double pass counter flow solar air collector with porous material in the second air passage is one of the important and attractive design improvement that has been proposed to improve the thermal performance. This paper presents theoretical and experimental analysis of double pass solar air collector with and without porous material. A mathematical model has been developed based on volumetric heat transfer coefficient. Effects of various parameters on the thermal performance and pressure drop characteristics have been discussed. Comparison of results reveals that the thermal efficiency of double pass solar air collector with porous absorbing material is 20–25% and 30–35% higher than that of double pass solar air collector without porous absorbing material and single pass collector respectively.

Due to exciting size-dependent chemical and physical properties, nanoscale materials have extensive range of applications compared with microstructural particles. CuO nanoparticles are very important among transition metal oxides because of their large number of applications. Quantum dots (QDs) of CuO (copper oxide) were prepared by the innovative ultrasonication method. Ultrasonic sound is used in this synthesis method to synthesize QDs of copper oxide. Structural and optical properties were studied in this research work. X-ray diffraction was used to study the formation of structural phase CuO QDs and found to be single phasic without any impurity. Transmission electron microscopic measurements were performed to study the morphology of QDs of CuO, which confirms spherical QDs with an average diameter of [Formula: see text]4[Formula: see text]nm. In optical studies, absorption spectra of the CuO were analyzed by using UV–visible spectroscopy.

Solar collector is a type of heat exchanger which transfers solar radiation energy into the heat energy. Conventional solar air collectors have poor thermal efficiency primarily due to high heat losses and low convective heat transfer coefficient between the absorber plate and flowing air stream, leading to higher absorber plate temperature and greater thermal losses. Attempts have been made to improve the thermal performance of conventional solar air collectors by employing various design and flow arrangements. Double pass counter flow solar air collector with porous material in the second air passage is one of the important and effective design improvement that has been proposed to improve the thermal performance. This paper presents the performance and economic analysis of double pass solar air collector with and without porous material. Effects of various parameters on the thermal performance and pressure drop characteristics have been studied experimentally. The study concludes that double pass arrangement with porous material is economical and having short payback period. Also, the thermal performance of double pass solar air collector with porous material is significantly higher compared to double pass solar air collector without porous material and single pass arrangement.Copyright © 2011 by ASME