Solar Salt Latent Heat Thermal Storage for a Small Solar Organic Rankine Cycle Plant

Costa, S.; Mahkamov, Khamid; Kenisarin, Murat; Ismail, Mohammad; Lynn, Kevin; Halimic, Elvedin; Mullen, David

doi:10.1115/1.4044557

Cited by 26 publications

(12 citation statements)

References 26 publications

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“… 34 The melting temperature range of bulk solar salt is quite broad showing a peak maximum at 222 °C, which is very close to 220 °C reported in the literature. 35 The melting temperatures of all MS/AAO composites decreased considerably compared to bulk salt. Although there is no systematic decrease in melting temperatures with decreasing pore diameter for all MS/AAO templates, a significant decrease is observed for all composite components when compared to the bulk ( Figure 1 ).…”

Section: Resultsmentioning

confidence: 95%

Melting Temperature Depression and Phase Transitions of Nitrate-Based Molten Salts in Nanoconfinement

et al. 2022

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Hybrids of nitrate-based molten salts (KNO 3 , NaNO 3 , and Solar Salt) and anodic aluminum oxide (AAO) with various pore sizes (between 25 and 380 nm) were designed for concentrated solar power (CSP) plants to achieve low melting point (<200 °C) and high thermal conductivity (>1 W m –1 K –1 ). AAO pore surfaces were passivated with octadecyl phosphonic acid (ODPA), and the results were compared with as-anodized AAO. The change in phase transition temperatures and melting temperatures of salts was investigated as a function of pore diameter. Melting temperatures decreased for all salts inside AAO with different pore sizes while the highest melting temperature decrease (Δ T = 173 ± 2 °C) was observed for KNO 3 filled in AAO with a pore diameter of 380 nm. Another nanoconfinement effect was observed in the crystal phases of the salts. The ferroelectric phase of KNO 3 (γ-phase) formed at room temperature for KNO 3 /AAO hybrids with pore size larger than 35 nm. Thermal conductivity values of molten salt (MS)/AAO hybrids were obtained by thermal property analysis (TPS) at room temperature and above melting temperatures of the salts. The highest increase in thermal conductivity was observed as 73% for KNO 3 /AAO-35 nm. For NaNO 3 /AAO-380 nm hybrids, the thermal conductivity coefficient was 1.224 ± 0.019 at room temperature. To determine the capacity and efficiency of MS/AAO hybrids during the heat transfer process, the energy storage density per unit volume (J m –3 ) was calculated. The highest energy storage capacity was calculated as 2390 MJ m –3 for KNO 3 /AAO with a pore diameter of 400 nm. This value is approximately five times higher than that of bulk salt.

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Section: Resultsmentioning

confidence: 95%

Melting Temperature Depression and Phase Transitions of Nitrate-Based Molten Salts in Nanoconfinement

et al. 2022

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“…In the project, other methods for increasing the thermal conductivity of pure solar salt were also investigated, including the use of expanded graphite and metal foams [12].…”

Section: Latent Heat Thermal Storage Systemmentioning

confidence: 99%

Solar Salt Latent Heat Thermal Storage for a Small Solar Organic Rankine Cycle Plant

Costa

Mahkamov

Kenisarin

et al. 2018

ASME 2018 12th International Conference on Energy Sustainability

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The design of the latent heat thermal storage system (LHTESS) was developed with a thermal capacity of about 100 kW h as a part of small solar plant based on the organic Rankine cycle (ORC). The phase change material (PCM) used is solar salt with the melting/solidification temperature of about 220°C. Thermophysical properties of the PCM were measured, including its phase transition temperature, heat of fusion, specific heat, and thermal conductivity. The design of the thermal storage was finalized by means of the 3D computational fluid dynamics analysis. The thermal storage system is modular, and the thermal energy is delivered with the use of thermal oil, heated by Fresnel mirrors. The heat is transferred into and from the PCM in the casing using bidirectional heat pipes, filled with water. A set of metallic screens are installed in the box with the pitch of 8-10 mm to enhance the heat transfer from heat pipes to the PCM and vice-versa during the charging and discharging processes, which take about 4 h. This work presents a numerical study on the use of metallic fins without thermal bonding as a heat transfer enhancement method for the solar salt LHTESS. The results show that the absence of the thermal bonding between fins and heat pipes (there was a gap of 0.5 mm between them) did not result in a significant reduction of charging or discharging periods. As expected, aluminum fins provide better performance in comparison with steel ones due to the difference in the material conductivity. The main advantage observed for the case of using aluminum fins was the lower temperature gradient across the LHTESS.

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“…A literature review shows that a few papers are treating coupled TES and ORC systems, and most of these papers are related to systems applied for solar thermal energy conversion. Costa S-C et al [9] analyzed the use of latent thermal energy storage for a small solar power plant equipped with the ORC system. The authors numerically analyzed the use of ribs without thermal bonding as a method to improve heat transfer in phase-change thermal energy storage material (PCM).…”

Section: Introductionmentioning

confidence: 99%

Sizing the Thermal Energy Storage Device Utilizing Phase Change Material (PCM) for Low-Temperature Organic Rankine Cycle Systems Employing Selected Hydrocarbons

et al. 2022

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Thermal energy storage (TES) looks to be a promising technology for recovering waste heat or other intermittent heat sources, especially if it is coupled with the organic Rankine cycle (ORC) system. This system may use a variety of heat storage materials, including solids, liquids, and phase change materials (PCM). This article discusses the use of PCM as a thermal energy storage material in TES systems coupled with ORC systems. Other TES configurations may be used in ORC; however, in this article, the TES is solely used in heat exchangers, i.e., evaporator and liquid heater. The goal of this research is to establish a dimensionless storage mass parameter for sizing TES-evaporator (TES-EVA) or TES-liquid heater (TES-LH) devices for ORCs. Furthermore, the model of this system was created in the MATLAB environment using the chosen hydrocarbons as ORC working fluids. The obtained modelling results provide a novel point of view that scientists and engineers may employ while developing the TES-EVA or TES-LH utilizing PCM for ORC.

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Solar Salt Latent Heat Thermal Storage for a Small Solar Organic Rankine Cycle Plant

Cited by 26 publications

References 26 publications

Melting Temperature Depression and Phase Transitions of Nitrate-Based Molten Salts in Nanoconfinement

Melting Temperature Depression and Phase Transitions of Nitrate-Based Molten Salts in Nanoconfinement

Solar Salt Latent Heat Thermal Storage for a Small Solar Organic Rankine Cycle Plant

Sizing the Thermal Energy Storage Device Utilizing Phase Change Material (PCM) for Low-Temperature Organic Rankine Cycle Systems Employing Selected Hydrocarbons

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