scholarly journals Experimental Research on the Selective Absorption of Solar Energy by Hybrid Nanofluids

Energies ◽  
2021 ◽  
Vol 14 (23) ◽  
pp. 8186
Author(s):  
Xin Jin ◽  
Guiping Lin ◽  
Haichuan Jin ◽  
Zunru Fu ◽  
Haoyang Sun

As low-cost, widely distributed and easily accessible renewable clean energy, solar energy has attracted more and more attention. Direct absorption solar collectors can convert solar energy into heat, but their efficiency is closely related to the absorption performance of the working fluid. In order to improve the absorption efficiency of direct absorption solar collectors, an experimental study on the selective absorption of solar energy by hybrid nanofluids was carried out. Five hybrid nanofluids were prepared and characterized, and the energy transfer advantages of hybrid nanofluid over single nanofluid were carefully studied. Experiments have found that the light-to-heat conversion properties of hybrid nanofluids show no obvious advantages or disadvantages compared with single nanofluid, and their performance is closely related to the types of nanoparticles. In addition, the hybrid nanofluid generally has two peaks, exactly the same as the single nanofluid in the mixed component, but the absorption curve is flatter than that of the single nanofluid. Further research of more types of hybrid nanofluids can provide new insights into the use of solar energy.

Nanomaterials ◽  
2021 ◽  
Vol 11 (1) ◽  
pp. 136
Author(s):  
Solomon O. Giwa ◽  
Mohsen Sharifpur ◽  
Mohammad H. Ahmadi ◽  
S. M. Sohel Murshed ◽  
Josua P. Meyer

The superiority of nanofluid over conventional working fluid has been well researched and proven. Newest on the horizon is the hybrid nanofluid currently being examined due to its improved thermal properties. This paper examined the viscosity and electrical conductivity of deionized water (DIW)-based multiwalled carbon nanotube (MWCNT)-Fe2O3 (20:80) nanofluids at temperatures and volume concentrations ranging from 15 °C to 55 °C and 0.1–1.5%, respectively. The morphology of the suspended hybrid nanofluids was characterized using a transmission electron microscope, and the stability was monitored using visual inspection, UV–visible, and viscosity-checking techniques. With the aid of a viscometer and electrical conductivity meter, the viscosity and electrical conductivity of the hybrid nanofluids were determined, respectively. The MWCNT-Fe2O3/DIW nanofluids were found to be stable and well suspended. Both the electrical conductivity and viscosity of the hybrid nanofluids were augmented with respect to increasing volume concentration. In contrast, the temperature rise was noticed to diminish the viscosity of the nanofluids, but it enhanced electrical conductivity. Maximum increments of 35.7% and 1676.4% were obtained for the viscosity and electrical conductivity of the hybrid nanofluids, respectively, when compared with the base fluid. The obtained results were observed to agree with previous studies in the literature. After fitting the obtained experimental data, high accuracy was achieved with the formulated correlations for estimating the electrical conductivity and viscosity. The examined hybrid nanofluid was noticed to possess a lesser viscosity in comparison with the mono-particle nanofluid of Fe2O3/water, which was good for engineering applications as the pumping power would be reduced.


2020 ◽  
Vol 6 (2) ◽  
pp. 72-81 ◽  
Author(s):  
Morteza Anbarsooz ◽  
Maryam Amiri ◽  
Iman Rashidi ◽  
Mohammad Javadi

Background: Enhancing the heat transfer rate in solar collectors is an essential factor for reducing the size of the system. Yet, various methods have been presented in the literature to increase the heat transfer rate from an absorber to the heat transfer fluid. The most important methods are: the use of evacuated receivers, addition of swirl generators/turbulators and use of various nanofluids as the heat transfer fluid. Objective: The current study reviews the achievements in the enhancement of solar collectors’ heat transfer process using various types of nanofluids. The review revealed that the most widely employed nanoparticles are Al2O3 and Carbon nanotubes (CNTs) and the most popular base fluid is water. Most of the investigations are performed on indirect solar collectors, while recently, the researchers focused on direct absorption methods. In the indirect absorption collectors, the thermal conductivity of the working fluid is essential, while in a direct absorption collector, the optical properties are also crucial. Optimization of the optical parameters along with the thermophysical properties of the nanofluid is suggested for the applications of solar collector.


Author(s):  
Jon T. Van Lew ◽  
Peiwen Li ◽  
Cho Lik Chan ◽  
Wafaa Karaki ◽  
Jake Stephens

Parabolic trough power systems utilizing concentrated solar energy have proven their worth as a means for generating electricity. However, one major aspect preventing the technologies widespread acceptance is the deliverability of energy beyond a narrow window during peak hours of the sun. Thermal storage is a viable option to enhance the dispatchability of the solar energy and an economically feasible option is a thermocline storage system with a low-cost filler material. Utilization of thermocline storage facilities have been studied in the past and this paper hopes to expand upon that knowledge. The current study aimed to effectively model the heat transfer of a working fluid interacting with filler material. An effective numerical method and efficient computation schemes were developed and verified. A thermocline storage system was modeled under specific conditions and results of great significance to heat storage design and operation were obtained.


2018 ◽  
Vol 15 (1) ◽  
pp. 27-39
Author(s):  
Ranga Babu J.A. ◽  
Kiran Kumar K. ◽  
Srinivasa Rao S.

Purpose This paper aims to present an analytical investigation of energy and exergy performance on a solar flat plate collector (SFPC) with Cu-CuO/water hybrid nanofluid, Cu/water and CuO/water nanofluids as collector running fluids. Design/methodology/approach Heat transfer characteristics, pressure drop and energy and exergy efficiencies of SFPC working on these nanofluids are investigated and compared. In this study, a comparison is made by varying the mass flow rates and nanoparticle volume concentration. Thermophysical properties of hybrid nanofluids are estimated using distinctive correlations available in the open literature. Then, the influence of these properties on energy and exergy efficiencies of SFPC is discussed in detail. Findings Energy analysis reveals that by introducing the hybrid nanoparticles in water, the thermal conductivity of the working fluid is enhanced by 17.52 per cent and that of the individual constituents is enhanced by 15.72 and 15.35 per cent for Cu/water and CuO/water nanofluids, respectively. This resulted in 2.16 per cent improvement in useful heat gain for hybrid nanofluid and 1.03 and 0.91 per cent improvement in heat gain for Cu/water and CuO/water nanofluids, respectively. In line with the above, the collector efficiency increased by 2.175 per cent for the hybrid nanofluid and 0.93 and 1.05 per cent enhancement for Cu/water and CuO/water nanofluids, respectively. Exergy analysis elucidates that by using the hybrid nanofluid, exergy efficiency is increased by 2.59 per cent, whereas it is 2.32 and 2.18 per cent enhancement for Cu/water and CuO/water nanofluids, respectively. Entropy generation is reduced by 3.31, 2.35 and 2.96 per cent for Cu-CuO/water, Cu/water and CuO/water nanofluids, respectively, as compared to water. Research limitations/implications However, this is associated with a penalty of increment in pressure drop of 2.92, 3.09 and 2.74 per cent for Cu-CuO/water, Cu/water and CuO/water nanofluids, respectively, compared with water. Originality/value It is clear from the analysis that Cu-CuO/water hybrid nanofluids possess notable increment in both energy and exergy efficiencies to use them in SFPCs.


Coatings ◽  
2020 ◽  
Vol 10 (6) ◽  
pp. 562
Author(s):  
Imyhamy M. Dharmadasa

Photovoltaic (PV) technology is rapidly entering the energy market, providing clean energy for sustainable development in society, reducing air pollution. In order to accelerate the use of PV solar energy, both an improvement in conversion efficiency and reduction in manufacturing cost should be carried out continuously in the future. This can be achieved by the use of advanced thin film materials produced by low-cost growth techniques in novel device architectures. This effort intends to provide the latest research results on thin film photovoltaic solar energy materials in one place. This Special Issue presents the growth and characterisation of several PV solar energy materials using low-cost techniques to utilise in new device structures after optimisation. This will therefore provide specialists in the field with useful references and new insights into the subject. It is hoped that this common platform will serve as a stepping-stone for further development of this highly important field.


Energies ◽  
2021 ◽  
Vol 14 (10) ◽  
pp. 2892
Author(s):  
Hossein Javadi ◽  
Javier F. Urchueguia ◽  
Seyed Soheil Mousavi Ajarostaghi ◽  
Borja Badenes

In this numerical study, 4 types of hybrid nanofluid, including Ag-MgO/water, TiO2-Cu/water, Al2O3-CuO/water, and Fe3O4-multi-wall carbon nanotube/water, have been considered potential working fluid in a single U-tube borehole heat exchanger. The selected hybrid nanofluid is then analyzed by changing the volume fraction and the Reynolds number. Based on the numerical results, Ag-MgO/water hybrid nanofluid is chosen as the most favorable heat carrier fluid, among others, considering its superior effectiveness, minor pressure drop, and appropriate thermal resistance compared to the pure water. Moreover, it was indicated that all cases of Ag-MgO/water hybrid nanofluid at various volume fractions (from 0.05 to 0.20) and Reynolds numbers (from 3200 to 6200) could achieve better effectiveness and lower thermal resistances, but higher pressure drops compared to the corresponding cases of pure water. Nevertheless, all the evaluated hybrid nanofluids present lower coefficient of performance (COP)-improvement than unity which means that applying them as working fluid is not economically viable because of having higher pressure drop than the heat transfer enhancement.


2021 ◽  
Vol 39 (4) ◽  
pp. 1321-1327
Author(s):  
Khalid Faisal Sultan ◽  
Hosham salim Anead ◽  
Ameer Abed Jaddoa

In this paper, for two separate half-breed Nano liquids, Ag (25nm) + refined water and Ag (50nm) + Zn (50nm)-refined water tentatively considered at the vehicle radiator, the execution of restricted convection. Four distinct cross-breed Nano liquid concentrations in the range of 2-6 vol %. The increase of half breed nanoparticles into the refined water as a base liquid was organized by percentage. Within the range of 20 l/min-60 l /min, the coolant flow rate is altered. Inside the warm trade, Crossover Nano coolants show colossal change compared to the refined water. Ag-refined water cross breed Nano liquid's warm exchange execution was found to be much better than Ag + Zn-refined water half breed Nano coolant. In addition, with the rise in the concentration of half breed nanoparticle and half breed Nano fluid velocity, the Nusselt number is found to expand. In the advancement of the warm exchange rate, Mono and hybrid nanofluid forms play a very important role in enhancing the heat transfer and refrigeration of car radiators. With an increase in concentration of half-breed nanoparticles for the primary form about 44 percent warm exchange transition, expansion of 6 vol percent crossover nanoparticles were achieved with the rate of warm exchange. In comparison to the current form of cross breed nanoparticles, with an expansion of 6 percent vol concentration, 22 percent extended. The exergy in flow, exergy destruction and exergy efficiency of mono nanofluid (Ag +Dw) are greater than hybrid nanofluid (Ag + Zn + Dw) and distilled water. The exergy inflow, exergy destruction, and exergy efficiency as the concentration of nanoparticles increases for the two forms of mono and hybrid nanofluid. The values parameters of the mono nanofluid (Ag + Dw) such as exergy in flow, exergy destruction and exergy efficiency at 6 vol% were 572 W, 460 W, 72% respectively while in hybrid nanofluids (Ag + Zn + Dw) were 420W, 282W, 51%. The use of mono and hybrid nanofluid as a working fluid results in higher efficiency of heat transfer, which promotes the performance of the car engine and decreases fuel consumption.


2021 ◽  
Vol 10 (2) ◽  
pp. 147-171
Author(s):  
L. Syam Sundar ◽  
Solomon Mesfin ◽  
Yihun Tefera Sintie ◽  
V. Punnaiah ◽  
Ali J. Chamkha ◽  
...  

Energy demand is high in all parts of the world, mostly in all industrial sectors. To meet the energy demand the fossil fuel is the only way. Due to rapid industrial growth and use of fossil fuel result in global warming and environmental pollution. Moreover, the limited availability of the fossil fuels, it is necessary to depend on the renewable energy sources. Promising renewable energy in the world is solar energy, which is available largely on the earth surface. The solar energy can be converted into thermal energy in the solar flat plate collector. The collector thermal efficiency is purely depends on the working fluid used in it. Most of the studies revealed that replacing the working fluid with high thermal conductivity fluids called as nanofluids and hybrid nanofluids can improve the collector thermal efficiency. Few decades back studies have been conducted with nanofluids in solar collectors. Currently the researchers are working on solar collectors for further improvement of its efficiency using hybrid nanofluids. In this review paper, we will discuss about the synthesis of hybrid nanoparticles, hybrid nanofluids, characterization, thermophysical properties, and application of hybrid nanofluids in solar flat plate collector under natural and forced circulation of fluid. The research gap in the solar collector is also discussed in this article. This paper also explains about the heat transfer capabilities of hybrid nanofluids especially used solar collectors.


Sign in / Sign up

Export Citation Format

Share Document