scholarly journals Theoretical Design of a Multilayer Based Spectrally Selective Solar Absorber Applied Under Ambient Conditions

2021 ◽  
Vol 9 ◽  
Author(s):  
Kuang Shi ◽  
Huaiyu Liu ◽  
Lei Wang ◽  
Yu Bie ◽  
Yue Yang
Keyword(s):  
High Temperature ◽  
Multilayer Film ◽  
Low Cost ◽  
Solar Thermal ◽  
Solar Thermal Energy ◽  
Ambient Conditions ◽  
Solar Absorption ◽  
Solar Absorptance ◽  
Energy Density Distribution ◽  
Solar Absorber

With the increasing of global energy requirements and environmental problems, the use of solar thermal energy has attracted widespread attention. The selective solar absorption coating is the most important part of a solar thermal conversion device. At present, most of the coatings work well in a vacuum at a high temperature, while not stably in the air environment. Based on the high-temperature resistant and infrared-reflective properties of ITO, a multilayer film of SiO2/Si3N4/SiO2/ITO/Cr has been designed as a selective solar absorber. The genetic algorithm is applied to optimize the material and thickness selection for each layer. The results show that the optimized multilayer film could achieve a high solar absorptance up to 90% while keeping a relatively low infrared emittance around 50% for temperature change between 600°C and 900°C. All the materials composing this film have been tested before to be chemically stable at a high temperature up to 900°C in the air environment. It is also adaptive to different incident angles from 0° to 60°. The finite-difference time-domain method was also adopted to plot the energy density distribution for different wavelengths, which provided the underlying mechanism for the selective emission spectrum. The findings in this study would provide valuable guidance to design a low-cost selective solar absorption coating without the need for vacuum generation.

Tungsten Nanowire Metamaterials as Selective Solar Thermal Absorbers by Excitation of Magnetic Polaritons

2016 ◽  
Author(s):  
J.-Y. Chang ◽  
H. Wang ◽  
L. P. Wang
Keyword(s):  
High Efficiency ◽  
Low Cost ◽  
Nanowire Array ◽  
Radiative Properties ◽  
Solar Thermal ◽  
Solar Thermal Energy ◽  
Nanowire Diameter ◽  
Solar Absorber ◽  
Potential Applicability ◽  
Magnetic Polariton

The present study focuses on nanowire based metamaterials with excitation of magnetic polariton (MP) as selective solar absorbers. Finite-difference time-domain simulation is employed for numerically designing a broadband solar absorber made of lossy tungsten nanowires which exhibit spectral selectivity due to the excitation of MP. An inductor-capacitor circuit model of the nanowire array is developed in order to predict the resonance wavelengths of the MP harmonic modes. The effects of geometric parameters such as nanowire diameter, height, and array period are investigated and understood on tuning the magnetic polariton resonance and the resulting optical and radiative properties. In addition, the independence of incidence angles is demonstrated, which illustrates the potential applicability of the nanowire-based metamaterial as a high-efficiency wide-angle selective solar absorber. The results will facilitate the design of novel low-cost and high-efficiency materials for enhancing solar thermal energy harvesting and conversion.

Ceramic Technology for Solar Thermal Receivers

1983 ◽  
Vol 105 (1) ◽  
pp. 73-79
Author(s):  
A. A. Kudirka ◽  
R. H. Smoak
Keyword(s):  
Thermal Energy ◽  
Low Cost ◽  
Ceramic Materials ◽  
Ceramic Technology ◽  
Solar Thermal ◽  
Receiver Design ◽  
Solar Thermal Energy ◽  
Energy Applications ◽  
Temperature Capability ◽  
Solar Applications

Development of ceramic receiver technology for advanced solar thermal energy applications is being pursued in order to achieve significant reductions in energy cost and increase the potential application of solar thermal energy. Basically, structural ceramics are being seriously considered for solar applications because of their high temperature capability, their nonstrategic nature, and their potential for low cost. In this paper, candidate ceramic materials for solar receivers and their characteristics are described, potentially applicable fabrication and processing methods are discussed, and their applicability and promise for solar receivers is assessed. Receiver design requirements as well as system requirements for solar applications are reviewed. Promising areas of application of ceramic receivers in the near future are also discussed. Current ceramic receiver development status and plans are described, including one receiver which has been successfully tested at gas exit temperatures of up to 1425°C.

scholarly journals Design and development of solar dryer for food preservation

2019 ◽  
Vol 54 (2) ◽  
pp. 155-160
Author(s):  
S Tabassum ◽  
MS Bashar ◽  
MS Islam ◽  
A Sharmin ◽  
SC Debnath ◽  
...  
Keyword(s):  
Thermal Energy ◽  
Low Cost ◽  
Geographical Location ◽  
Food Preservation ◽  
Solar Thermal ◽  
Solar Thermal Energy ◽  
Alternative Source ◽  
Solar Dryer ◽  
Large Production ◽  
Dry Food

Solar thermal energy is an alternative source of energy which can be used for drying vegetables, fishes, fruits or other kinds of material, such as wood. In Bangladesh, there exist significant post-harvest losses of agricultural products due to lack of the use of proper preservation system. Drying by using solar thermal energy can be an effective solution for this loss. As Bangladesh is situated in latitude 23°43’N and longitude 90°26’E, this is very much suitable to use solar thermal energy. To reduce the limitations of the natural sun drying e.g. exposure of the foodstuff to rain and dust; uncontrolled drying; exposure to direct sunlight; infestation by insects etc., two types of solar dryer (low cost solar dryer for small production and solar dryer for large production) were developed. The design was based on the geographical location of Dhaka, Bangladesh. The experiments were conducted to dry vegetables and fishes. The obtained results revealed that the temperatures inside the dryer were much higher than the ambient temperature. The rapid rate of drying proves its ability to dry food to keep in safe moisture level in a hygienic environment. Microbiological and nutritional values ensure a superior quality of the dried product also. Bangladesh J. Sci. Ind. Res.54(2), 155-160, 2019

A Review on Experimental and Numerical Investigations on Using Nanofluid in Volumetric Solar Energy Collectors

2014 ◽  
Author(s):  
Siamak Mirmasoumi ◽  
Mohammad Pourgol-Mohammad
Keyword(s):  
Heat Transfer ◽  
Power Plants ◽  
Radiant Energy ◽  
Solar Thermal ◽  
Working Fluid ◽  
Steam Generation ◽  
Solar Thermal Energy ◽  
Solar Absorption ◽  
Advantages And Disadvantages ◽  
Solar Power Plants

By a simple research in the scholarly articles, it can be realized that the tendency to using solar thermal energy has risen in the recent years due to its many reasonable advantages. In conventional solar thermal systems, HTFs (Heat Transfer Fluids) are pumped through the piping of a solar collector and after absorbing the solar radiant energy conveys it to water to make steam. No need to say that this method contains some losses via all methods of heat transfer. To solve this problem, researchers have shown that with direct steam generation, in which working fluid directly absorbs solar thermal and becomes vapor, solar power plants have the potential to be more productive. However, the aforesaid conventional HTFs don’t have efficient enough thermal properties and need to be improved. For this reason using nanofluid has become to some extent popular in heat transfer facilities like solar thermal collectors. In the present study, we are going to identify the advantages and disadvantages of using nanoparticles in direct solar absorption systems (DSASs). To achieve this, a general review on the experimental and numerical studies in this field is done. Additionally some of the most effective particles for such a special case, in which particles should have good radiative characteristics, are introduced. Finally, after discussion about the highlighted challenges of using nanofluids in DSASs, some helpful suggestions to overcome these problems will be presented.

Study of High Temperature Nanofluids Using Carbon Nanotubes (CNT) for Solar Thermal Storage Applications

2010 ◽  
Author(s):  
Byeongnam Jo ◽  
Debjyoti Banerjee
Keyword(s):  
Carbon Nanotubes ◽  
High Temperature ◽  
Specific Heat ◽  
Sodium Dodecyl ◽  
Eutectic Mixture ◽  
Lithium Carbonate ◽  
Solar Thermal ◽  
Molar Ratio ◽  
Solar Thermal Energy ◽  
Measured Specific Heat

The aim of this study is to investigate enhancement of thermal properties of various high temperature nanofluids using Carbon Nanotubes (CNT) for solar thermal energy storage applications. The specific heat of liquid carbonate salt eutectics that are doped with CNT was measured using Differential Scanning Calorimeter (DSC). A eutectic mixture of lithium carbonate (Li2CO3) and potassium carbonate (K2CO3) at a molar ratio of 62:38 is used as the base fluid (solvent). A surfactant (Sodium Dodecyl Sulfate or “SDS”) was used to obtain well-dispersed suspension of CNT in distilled water. This CNT suspension was added to an aqueous solution of two alkali carbonate salts in the form of a eutectic mixture. The resulting solution was evaporated on a hot-plate to obtain a dry mixture of CNT (at 1% concentration by weight) in the carbonate eutectic. The samples were synthesized for by evaporating at four different hotplate temperatures of 100 °C, 120 °C, 140 °C, and 160 °C. The results showed that specific heat capacities of carbonate eutectic-CNT nanofluids were linearly increased as the hotplate temperature was increased. At higher temperatures the water was evaporated faster — leading to less agglomeration of the nanoparticles in the nanofluids and thus resulting in higher values of the measured specific heat of the nanofluids.

scholarly journals Material Selection for Latent Heat Based High Temperature Solar Thermal Energy Storage

2015 ◽  
Vol 74 ◽  
pp. 1525-1532 ◽  
Author(s):  
Ramón Gutiérrez ◽  
Héctor García ◽  
Bruno Cardenas ◽  
Noel León
Keyword(s):  
High Temperature ◽  
Energy Storage ◽  
Latent Heat ◽  
Thermal Energy ◽  
Thermal Energy Storage ◽  
Material Selection ◽  
Solar Thermal ◽  
Solar Thermal Energy ◽  
Selection For
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