scholarly journals Preparation and characterization of nanofluids based on molten salts with enhanced thermophysical properties for thermal energy storage at concentrate solar power

Author(s):  
Yaroslav Grosu ◽  
Udayashankar Nithiyanantham ◽  
Luis González-Fernández ◽  
Abdessamad Faik
Author(s):  
Hani Tiznobaik ◽  
Donghyun Shin

In a concentrated solar power (CSP), high operating temperature (over 500 °C) is the key for enhancing the efficiency of the system. The operating temperature of the system mainly relies on thermal energy storage (TES) material. Existing TES materials such as mineral oil or paraffin wax cannot be applicable at high temperatures, since these materials are not thermally stable over 400 °C. However, very few materials are suitable and reliable for the high temperatures. Using molten salts (e.g., alkali nitrate, alkali carbonate, alkali chloride, etc.) as thermal energy storage material is an alternative way due to several benefits. They are cheap and environmentally safe compared with the conventional TES materials. They are thermally stable at higher temperatures (over 500 °C). However, their usage is limited due to low thermo-physical properties (e.g. Cp is less than 1.6 J/g°C). The low thermo-physical properties can be improved by dispersing nanoparticles into the salts. In this study, nanomaterials were synthesized by dispersing inorganic nanoparticles into ionic salts. Modulated differential scanning calorimeter (MDSC) was used to measure the heat capacity of the nanomaterials. Scanning electron microscopy (SEM) was used for material characteristic analysis. Hence, the application of the nanomaterials as thermal energy storage in a concentrated solar power was explored.


Energies ◽  
2019 ◽  
Vol 12 (7) ◽  
pp. 1394 ◽  
Author(s):  
Xiaoru Zhuang ◽  
Xinhai Xu ◽  
Wenrui Liu ◽  
Wenfu Xu

In recent years, the Chinese government has vigorously promoted the development of concentrating solar power (CSP) technology. For the commercialization of CSP technology, economically competitive costs of electricity generation is one of the major obstacles. However, studies of electricity generation cost analysis for CSP systems in China, particularly for the tower systems, are quite limited. This paper conducts an economic analysis by applying a levelized cost of electricity (LCOE) model for 100 MW tower CSP plants in five locations in China with four different molten-salts for thermal energy storage (TES). The results show that it is inappropriate to build a tower CSP plant nearby Shenzhen and Shanghai. The solar salt (NaNO3-KNO3, 60-40 wt.%) has lower LCOE than the other three new molten-salts. In order to calculate the time when the grid parity would be reached, four scenarios for CSP development roadmap proposed by International Energy Agency (IEA) were considered in this study. It was found that the LCOE of tower CSP would reach the grid parity in the years of 2038–2041 in the case of no future penalties for the CO2 emissions. This study can provide support information for the Chinese government to formulate incentive policies for the CSP industry.


Molecules ◽  
2019 ◽  
Vol 24 (20) ◽  
pp. 3777 ◽  
Author(s):  
Anna Canela-Xandri ◽  
Gemma Villorbina ◽  
Mercè Balcells ◽  
Xavier Fernández-Francos ◽  
Luisa F. Cabeza ◽  
...  

Nine monoamides were synthesized from carboxylic acids (C8–C18) and crude glycerol. The final monoamides were the result of a rearrangement of the acyl chain during the final hydrogenation process. The purity of the final compounds was determined by spectroscopic and mass spectrometry (MS) techniques. The thermophysical properties of solid monoamides were investigated to determine their capability to act as phase change materials (PCM) in thermal energy storage. Thermophysical properties were determined with a differential scanning calorimeter (DSC). The melting temperatures of the analyzed material ranged from 62.2 °C to 116.4 °C. The analyzed enthalpy of these monoamides ranged from 25.8 kJ/kg to 149.7 kJ/kg. Enthalpy values are analyzed considering the carbon chain and the formation of hydrogen bonds.


Author(s):  
Ramaprasath Devaradjane ◽  
Donghyun Shin

Storage of thermal energy using molten salt materials has been widely explored for concentrating solar power. Since these power plants use thermodynamic cycle, the overall system cycle efficiency significantly relies on the thermal energy storage temperature. Therefore, increasing the thermal energy storage temperature and decreasing the amount of material needed can result in reducing the cost of solar energy. Molten salts are stable up to 700°C, relatively cheap, and safe to the environment. However, the heat capacity of the molten salts is typically low (∼1.5 J/gK) compared to other thermal storage materials. The low heat capacity of molten salts can be improved by dispersing nanoparticles. In this study, we synthesized molten salt nanomaterial by dispersing oxide nanoparticles into selected molten salts. Heat capacity measurements were performed using a modulated differential scanning calorimeter. Materials characterization studies were performed using a scanning electron microscopy. Hence, we evaluated the use of the molten salt nanomaterials as thermal energy storage media in concentrated solar power applications. Increase in the specific heat capacity of the molten salt is also demonstrated on addition with Nano materials of specific size and quantity.


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