Nitrogen doped hybrid carbon based composite dispersed nanofluids as working fluid for low-temperature direct absorption solar collectors

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.

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Experimental investigation of stability and extinction coefficient of Al 2 O 3 –CuO binary nanoparticles dispersed in ethylene glycol–water mixture for low-temperature direct absorption solar collectors

Energy Conversion and Management ◽

10.1016/j.enconman.2015.11.034 ◽

2016 ◽

Vol 108 ◽

pp. 501-510 ◽

Cited By ~ 27

Author(s):

Amir Menbari ◽

Ali Akbar Alemrajabi ◽

Yousef Ghayeb

Keyword(s):

Experimental Investigation ◽

Low Temperature ◽

Ethylene Glycol ◽

Extinction Coefficient ◽

Water Mixture ◽

Solar Collectors ◽

Direct Absorption ◽

Binary Nanoparticles

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

Energies ◽

10.3390/en14238186 ◽

2021 ◽

Vol 14 (23) ◽

pp. 8186

Author(s):

Xin Jin ◽

Guiping Lin ◽

Haichuan Jin ◽

Zunru Fu ◽

Haoyang Sun

Keyword(s):

Solar Energy ◽

Low Cost ◽

Clean Energy ◽

Absorption Efficiency ◽

Working Fluid ◽

Hybrid Nanofluid ◽

Selective Absorption ◽

Solar Collectors ◽

Direct Absorption ◽

Hybrid Nanofluids

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.

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