Macroencapsulation of Sodium Nitrate for Thermal Energy Storage in Solar Thermal Power

Author(s):  
Swetha Pendyala ◽  
Prashanth Sridharan ◽  
Sarada Kuravi ◽  
Chand K. Jotshi ◽  
Manoj K. Ram ◽  
...  

Storage systems based on latent heat storage have high-energy storage density, which reduces the footprint of the system and the cost. However, phase change materials (PCMs) have very low thermal conductivities making them unsuitable for large-scale use without enhancing the effective thermal conductivity. In order to address the low thermal conductivity of the PCMs, macroencapsulation of PCMs is adopted as an effective technique. The macro encapsulation not only provides a self-supporting structure but also enhances the heat transfer rate. In this research, Sodium nitrate (NaNO3), a low cost PCM, was selected for thermal storage in a temperature range of 300–500°C. The PCM was encapsulated in a metal oxide cell using self-assembly reactions, hydrolysis, and simultaneous chemical oxidation at various temperatures. The metal oxide encapsulated PCM capsule was characterized using Fourier transform infrared spectroscopy (FTIR) and scanning electron microscopy (SEM). The cyclic stability and thermal performance of the capsules were also studied.

2021 ◽  
Author(s):  
Xiao Tang ◽  
Dong Zhou ◽  
Bao Zhang ◽  
Shijian Wang ◽  
Peng Li ◽  
...  

Abstract Non–aqueous rechargeable multivalent metal (Ca, Mg, Al, etc.) batteries are promising for large–scale energy storage due to their low cost. However, their practical applications face formidable challenges owing to low electrochemical reversibility and dendrite growth of multivalent metal anodes, sluggish kinetics of multivalent ion in metal oxide cathodes, and poor electrode compatibility of flammable organic electrolytes. To overcome these intrinsic hurdles, we develop aqueous multivalent ion batteries to replace the prevailing non–aqueous multivalent metal batteries by using wide–window super–concentrated aqueous gel electrolytes, the versatile high–capacity sulfur anodes, and high–voltage metal oxide cathodes. This rationally designed aqueous battery chemistry enables the long–lasting multivalent ion batteries featured with increased high energy density, reversibility and safety. As a demonstration model, a calcium ion−sulfur||metal oxide full cell exhibited a high energy density of 110 Wh kg–1 with outstanding cycling stability. Molecular dynamics modelling and experimental investigations revealed that the side reactions could be significantly restrained through the suppressed water activity and formation of protective inorganic solid electrolyte interphase in the aqueous gel electrolyte. The unique redox chemistry has also been successfully extended to aqueous magnesium ion and aluminum ion−sulfur||metal oxide batteries. This work will boost aqueous multivalent ion batteries for low−cost large–scale energy storage.


2018 ◽  
Vol 5 ◽  
pp. 4 ◽  
Author(s):  
Albert Ioan Tudor ◽  
Adrian Mihail Motoc ◽  
Cristina Florentina Ciobota ◽  
Dan. Nastase Ciobota ◽  
Radu Robert Piticescu ◽  
...  

Thermal energy storage systems using phase change materials (PCMs) as latent heat storage are one of the main challenges at European level in improving the performances and efficiency of concentrated solar power energy generation due to their high energy density. PCM with high working temperatures in the temperature range 300–500 °C are required for these purposes. However their use is still limited due to the problems raised by the corrosion of the majority of high temperature PCMs and lower thermal transfer properties. Micro-encapsulation was proposed as one method to overcome these problems. Different micro-encapsulation methods proposed in the literature are presented and discussed. An original process for the micro-encapsulation of potassium nitrate as PCM in inorganic zinc oxide shells based on a solvothermal method followed by spray drying to produce microcapsules with controlled phase composition and distribution is proposed and their transformation temperatures and enthalpies measured by differential scanning calorimetry are presented.


2021 ◽  
Vol 11 (2) ◽  
pp. 468
Author(s):  
Bo Zhang ◽  
Haibin Yang ◽  
Tao Xu ◽  
Waiching Tang ◽  
Hongzhi Cui

Phase change materials (PCMs) have received extensive attention due to their high latent heat storage density and isothermal behavior during heat charging and discharging processes. The application of PCMs in buildings would match energy supply and demand by using solar energy effectively, thereby reducing building energy consumption. In this study, a diatomite/paraffin (DP) composite was prepared through a vacuum-impregnated process. The thermo-physical performance, thermal stability, chemical structure and thermal reliability of the DP composite were evaluated. To develop a structural–functional integrated energy storage building material, carbon fibers (CF) were chosen as the reinforcing material. The mechanical and thermal properties of CF-reinforced DP/gypsum were examined. It is evident that the flexural strength and thermal conductivity of DP/gypsum containing 1 wt. % CF increased by 176.0% and 20.3%, respectively. In addition, the results of room model testing demonstrated that the presence of CF could enhance the overall thermal conductivity and improve the thermo-regulated performance of DP/gypsum. Moreover, the payback period of applying CF-reinforced DP/gypsum in residential buildings is approximately 23.31 years, which is much less than the average life span of buildings. Overall, the CF reinforced DP/gypsum composite is promising for thermal energy storage applications.


2021 ◽  
Vol 65 (2-4) ◽  
pp. 201-204
Author(s):  
Alessandro Ribezzo ◽  
Matteo Fasano ◽  
Luca Bergamasco ◽  
Luigi Mongibello ◽  
Eliodoro Chiavazzo

One major limitation of phase-change materials (PCM) for thermal energy storage comes from their poor thermal conductivity hindering heat transfer process and power density. Nanocomposites PCMs, where highly conductive nanofillers are dispersed into PCM matrices, have been exploited in the past decades as novel latent heat storage materials with enhanced thermal conductivity. A computational model based on continuum simulations capable to link microscopic characteristics of nanofillers and the bulk PCM with the macroscopic effective thermal conductivity of the resulting nanocomposite is the aim of this work. After preliminary mean-field simulations investigating the impact of the nanofiller aspect ratio on the thermal conductivity of the nanocomposite, finite element simulations at reduced aspect ratios have been performed with corrected thermal conductivity values of the filler, to take into account the thermal interface resistances between fillers and matrix. Finally, the thermal conductivity at the actual aspect ratios has been extrapolated by the results obtained at reduced aspect ratios thus saving computational time and meshing efforts. This method has been validated through comparison against previous literature evidence and new experimental characterizations of nanocomposite PCMs.


Author(s):  
Zhiqiang Luo ◽  
Silin Zheng ◽  
Shuo Zhao ◽  
Xin Jiao ◽  
Zongshuai Gong ◽  
...  

Benzoquinone with high theoretical capacity is anchored on N-plasma engraved porous carbon as a desirable cathode for rechargeable aqueous Zn-ion batteries. Such batteries display tremendous potential in large-scale energy storage applications.


Author(s):  
Karthik Nithyanandam ◽  
Ranga Pitchumani

Latent thermal energy storage (LTES) system offers high energy storage density and nearly isothermal operation for concentrating solar power generation. However, the low thermal conductivity possessed by the phase change material (PCM) used in LTES system limits the heat transfer rates. Utilizing thermosyphons to charge or discharge a LTES system offers a promising engineering solution to compensate for the low thermal conductivity of the PCM. The present work numerically investigates the enhancement in the thermal performance of charging and discharging process of LTES system by embedding thermosyphons. A transient, computational analysis of the LTES system with embedded thermosyphons is performed for both charging and discharging cycles. The influence of the design configuration of the system and the arrangement of the thermosyphons on the charge and discharge performance of the LTES installed in a concentrating solar power plant (CSP) is analyzed to identify configurations that lead to improved effectiveness.


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