Yaroslav Grosu

Yaroslav Grosu
CIC Energigune · Thermal Energy Storage (TES)

PhD

About

78
Publications
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904
Citations

Publications

Publications (78)
Article
Molten salts-based nanofluids are attractive candidates for thermal energy storage applications due to their enhanced thermophysical properties. However, their stability remains an open issue. In the present work, the size effect of SiO2 nanoparticles on the stability and thermophysical properties of molten binary nitrate salt was studied. For that...
Article
Establishing molecular mechanisms of wetting and drying of hydrophobic porous materials is a general problem for science and technology within the subcategories of the theory of liquids, chromatography, nanofluidics, energy storage, recuperation, and dissipation. In this article, we demonstrate a new way to tackle this problem by exploring the effe...
Preprint
Full-text available
It is widely agreed that phase change materials (PCMs) are of high interest for sustainable energy future. Many of the applications require anti-leakage properties of PCM, that can be accomplished through PCM encapsulation. In this study, scalable and considerably simplified approach based on the microfluidics principles was successfully designed f...
Article
Full-text available
The recovery and storage of process heat in industrial applications are some of the key factors to improve the sustainability and reliability of high temperature applications. In this sense, one of the main drawbacks is focused on the selection of proper thermal energy storage (TES) materials. This paper performs a full characterization of four pha...
Article
The demand for efficient and sustainable energy is continuously increasing. Among the many technologies with great potential within this field are nanofluids. Nevertheless, there is still a considerable lack of information regarding their erosive effects on systems materials. In this research, the tribological behaviour of aqueous 1.33 wt% TiO2 nan...
Article
Full-text available
Intrusion (wetting)/extrusion (drying) of liquids in/from lyophobic nanoporous systems is key in many fields, including chromatography, nanofluidics, biology, and energy materials. Here we demonstrate that secondary topological features decorating main channels of porous systems dramatically affect the intrusion/extrusion cycle. These secondary fea...
Article
Li2CO3–Na2CO3–K2CO3 salt is one of the candidates for 3rd generation concentrated solar power (CSP) plants, aiming to increase the operational temperature. This rise of temperature significantly increases the corrosion issue of molten salts. However, there is a lack of studies focused on the effect of salt flow on the corrosion kinetic for this ter...
Article
With renewables as the main candidate for future energy sources, efficient energy storage is considered a key to unlock its full potential. In this context, thermal energy storage (TES), particularly molten salt-based TES, is considered as an efficient, simple and a low-cost option. One of the main drawbacks for this technology is the corrosion of...
Article
Largely inspired by nature, hierarchical porous materials are attractive for a wide range of applications as they provide a unique combination of transport and interfacial properties. Hierarchical macro-nanoporous metals (HMNPM) are of particular interest due to their high thermal and electrical conductivities, high volumetric macroporosity as well...
Article
A new composite heat transfer fluid consisting of tetralin and fullerene has been proposed for photovoltaic thermal hybrid solar harvesting. It features a unique absorption spectrum that is capable of sharply cutting off solar energy irradiated in the range of wavelength from 300 to 650 nm, making it a perfect candidate for simultaneous harvesting...
Preprint
Full-text available
A new composite heat transfer fluid consisting of tetralin and fullerene has been proposed for photovoltaic thermal hybrid solar harvesting. It features a unique absorption spectrum that is capable of sharply cutting off solar energy irradiated in the range of wavelength from 300 to 650 nm, making it a perfect candidate for simultaneous harvesting...
Article
Full-text available
In this article, we review some recent theoretical results about intrusion and extrusion of non-wetting liquids in and out of cavities of nanotextured surfaces and nanoporous materials. Nanoscale confinement allows these processes to happen at conditions which significantly differ from bulk phase coexistence. In particular, the pressure at which a...
Article
Negative compressibility (NC) is a phenomenon when an object expands/shrinks in at least one of its dimensions upon compression/decompression. NC is very rare and is of great interest for a number of applications. In this work a gigantic (more than one order of magnitude higher compared to the reported values) NC effect was recorded during intrusio...
Article
Efficient and compact energy conversion is at the heart of the sustainable development of humanity. In this work it is demonstrated that hydrophobic flexible nanoporous materials can be used for thermal-to-mechanical energy conversion when coupled with water. In particular, a reversible nonhysteretic wetting-drying (contraction-expansion) cycle pro...
Article
Full-text available
On-demand access to renewable and environmentally friendly energy sources is critical to address current and future energy needs. To achieve this, the development of new mechanisms of efficient thermal energy storage (TES) is important to improve the overall energy storage capacity. Demonstrated here is the ideal concept that the thermal effect of...
Article
Materials or systems demonstrating negative linear compressibility (NLC), whose size increases (decreases) in at least one of their dimensions upon compression (decompression) are very rare. Materials demonstrating this effect in all their dimensions, negative volumetric compressibility (NVC), are exceptional. Here, by liquid porosimetry and in sit...
Article
Molten salts-based nanofluids have been widely considered for Thermal Energy Storage (TES) applications due to their enhanced thermophysical properties. However, the application of such fluids faces many challenges, among which are the correct determination of their properties, stability, compatibility with construction materials and the overall en...
Conference Paper
Molten salts are currently used at concentrated solar power (CSP) plants for thermal energy storage (TES) purposes. However, high-temperature corrosion by molten salts has detrimental effect on the investment costs and safety. This is particularly important for next generation CSP plants, where expected operational temperatures are very high. To en...
Article
Packed bed thermal energy storage system is a promising alternative to reduce the overall investment cost of a concentrating solar power plant. However, the choice of suitable filler materials depends on different steps and criteria in order to satisfy the requirements of the target application (e.g. operating temperatures, charging/discharging the...
Article
Next-generation concentrated solar power (CSP) plants are expected to work above the current temperature limit of 565 °C for the benefit of enhanced efficiency. This poses significant challenges in the construction materials, among others, in terms of corrosion. In this work, we investigate the spray-graphitization method to improve the compatibili...
Article
When compressed, the size of ordinary materials reduces. The opposite effect, when a material or system increases (decreases) its volume upon compression (decompression), is called Negative Compressibility (NC). NC is extremely rare, while being attractive for a wide range of applications. Here we demonstrate, by both experiments and MD simulations...
Article
Impregnation of Phase Change Materials (PCMs) into a porous medium is a promising way to stabilize their shape and improve thermal conductivity, which are essential for thermal energy storage and thermal management of small-size applications, such as electronic devices or batteries. However, in these composites a general understanding of how leakag...
Article
Hierarchical nanoporous metals are a new class of porous materials attractive for a wide range of applications due to their high thermal and electrical conductivity, transport properties, stability, etc. However, due to small pore size they suffer from low porosity which is essential for practical use. Here it is demonstrated that volumetric porosi...
Preprint
Full-text available
Impregnation of Phase Change Materials (PCMs) into a porous medium is a promising way to stabilize their shape and improve thermal conductivity which are essential for thermal energy storage and thermal management of small-size applications, such as electronic devices or batteries. However, in these composites a general understanding of how leakage...
Article
Two Al2O3 based nanofluids have been developed to increase the thermophysical properties of the molten salts used for thermal energy storage application at concentrated solar power plants. A novel simple dry preparation method by using a physical shaking technique was demonstrated in the present research work. A good dispersion of 1 wt% Al2O3 nanom...
Article
Three different sizes of the SiO2@Al2O3 core-shell nanoparticles were synthesized by tuning the silica precursor using the wet chemical route. The precise control of the outer shell diameter of SiO2 was controlled by optimum concertation of the silica precursor in the alumina solution. Gradual increment of the outer shell depth and the chain-like a...
Article
In this article the effect of a porous material´s flexibility on the dynamic reversibility of a non-wetting liquid intrusion was explored experimentally. For this purpose, high-pressure water intrusion together with high-pressure in-situ small angle neutron scattering were applied for superhydrophobic grafted silica and two metal-organic frameworks...
Article
Full-text available
Proper recording of thermophysical properties for molten salts (MSs) and molten salts based nanofluids (MSBNs) is of paramount importance for the thermal energy storage (TES) technology at concentrated solar power (CSP) plants. However, it is recognized by scientific and industrial communities to be non-trivial, because of molten salts creeping (sc...
Article
Full-text available
The aim of this paper is to explore Cu-Mg metallic alloys with high thermal conductivity as intermediate/hightemperature Phase Change Materials (PCMs) for latent heat storage at Concentrated Solar Power plants (CSP).Two binary eutectic alloys Mg84Cu16 and Mg59Cu41 (at.%) were investigated in terms of their structural, thermophysical and corrosion p...
Article
Hot corrosion is profoundly detrimental to construction elements in Concentrated Solar Power (CSP) plants affecting their lifetime, running costs and safety. In this work we have studied the anticorrosion effect of TiO2 nanoparticles additives on carbon steel using XRD, XPS with depth profiling, EDX and FIB/SEM techniques. The results revealed that...
Article
Efficient energy storage is a bottleneck for nearly every renewable energy technology. Thermal energy storage (TES) is widely considered as a relatively simple and reliable method, particularly for concentrated solar power (CSP) plants. Currently, considerable scientific effort is focused on the development of new molten salt-based nanofluids as st...
Article
Nanoscale science rapidly enters nearly every field of technology providing perspectives of new advanced applications. In the area of thermal energy storage (TES) doping molten salts with small amounts of nanoparticles represents tremendous interest due to the perspective of pronounced enhancement of their thermophysical properties. This is particu...
Conference Paper
The use of thermal energy storage (TES) for electricity production at concentrated solar power (CSP) plants has provided several important benefits, like lower environmental impact and higher dispatchability, compared to other methods. Many investigations have been focused on the enhancement of thermophysical properties of molten salts (TES materia...
Conference Paper
Full-text available
Natural rocks are a very promising option for medium temperature range (100-300 °C) thermal energy storage (TES) applications as they are low-cost and abundant in nature. For concentrated solar power (CSP) plant working in this temperature range, the state-of the art of TES (Two-tank molten salts system) is not an option as its storage materials ha...
Conference Paper
A novel latent heat storage material (LHS) Mg21Cu4 eutectic alloy is investigated in this work. For this study, X-ray diffraction (XRD) and scanning electron microscopy (SEM) were performed to evaluate the synthesis method and the eutectic composition. The differential scanning calorimetry (DSC) was applied in order to determine the thermal propert...
Conference Paper
In the recent years considerable interest of scientific and industrial communities in molten salts based nanofluids is evident. Such interest is motivated by the possibility of enhancement of thermophysical properties of molten salts by means of adding small concentrations of nanoparticles. This enhancement is particularly attractive for thermal en...
Article
In present study a new experimental data for the saturated liquid density and saturated vapor pressure along the boiling line for the solutions of the ”natural” refrigerant isobutane (R600a) with mineral compressor oil and solutions of R600a/compressor oil/fullerenes C60 is presented. Moreover, a new experimental data on the specific isobaric heat...
Article
Thermal energy storage (TES) is an efficient solution for improving the dispatchability of Concentrated Solar Power (CSP) plants. A system, consisting of two tanks with Solar Salt (NaNO3 60% wt. and KNO3 40% wt.) is commonly used. However, the investment cost of this technology is very high, due to the huge amount of salts required (thousands of to...
Article
Hierarchical porous metals are widely considered for practical use due to their attractive mechanical, thermophysical and transport properties. With the clear technological trend towards miniaturization, hierarchical nanoporous metals (HNMs) are particularly attractive. Control of porosity, stability as well as the development of new simple synthes...
Article
The laminar, transient and turbulent heat transfer and hydrodynamic of a new nanofluid isopropanol/Al2O3 is investigated in a closed flow loop with a horizontal mini-channel test section (3.5 mm inner diameter) under uniform heat flux conditions. The experiments performed at various inlet temperatures (15, 25, 35 C), mass flow rates (from 0.00076 to 0....
Article
In this contribution we explore by means of experiments, theory, and molecular dynamics the effect of pore morphology on the spontaneous extrusion of non-wetting liquids from nanopores. Understanding and controlling this phenomenon is central for manipulating nanoconfined liquids, e.g., in nanofluidic applications, drug delivery, and oil extraction...
Article
Full-text available
Corrosion is an important issue in high-temperature applications such as Concentrated Solar Power (CSP) technology, playing a crucial role in the long-term use of storage tanks, heat exchanger and piping materials which account for a considerable component of the investment costs. While there are many studies regarding the corrosion rates of contai...
Article
This paper presents a multilevel comparison between two thermal energy storage materials: quartzite as the most known thermocline energy storage material and magnetite as a new potential candidate. This comparison involves: thermal and thermophysical properties, cycling effect and thermocline thermal energy storage performances. In first, an experi...
Conference Paper
Full-text available
The aim of this paper is to investigate new classes of materials, metal alloys, as phase change materials (PCMs) for thermal energy storage (TES) application. In the first stage of this work, we discuss the considerations for the use of metal and metal alloys as PCMs for high temperature thermal storage applications, as well as summarize the litera...
Article
Full-text available
Thermal energy storage (TES) systems based on packed bed arrangements are proven to be a very promising route to decrease the levelized cost of electricity (LCOE) in concentrated solar power (CSP) plants. However, the compatibility between the TES material and the heat transfer fluid (HTF), which operate in direct contact, is known to be a major li...
Article
Understanding the effect of liquid viscosity in nanoconfinement is of paramount importance from both the fundamental and practical points of view. In particular, unexpected dynamic phenomena are ubiquitous in a broad range of nanofluidic applications. In this work, we used state-of-the-art high-pressure (P,V,T) calorimetry for direct observation of...
Article
https://authors.elsevier.com/a/1WlgJ4r6KusBAi Thermal energy storage (TES) technology is currently considered as a key solution to improve the performance of Concentrated Solar Power (CSP) plants in terms of their flexibility and dispatchability. Particularly, thermocline packed-bed single-tank configuration was shown to be a promising and economic...
Article
https://authors.elsevier.com/a/1WnkK4r6KusHNr The use of thermal energy storage (TES) systems at concentrated solar power (CSP) plants is one of the main ways of increasing the dispatchability and hence the competitiveness among other renewable energies. The thermocline packed bed TES technology is particularly attractive in terms of cost-effectiven...
Article
In this work, the compatibility of low-Cr carbon steel A516.Gr70 and stainless steels AISI 304 and AISI 316 with NaNO3-KNO3-Ca(NO3)2 (15–43–42 wt%) molten salt known as HitecXL was evaluated with the aim of determination the most suitable constructive material for a pilot thermocline thermal energy storage (TES) system of 20 MWh, which is under dev...
Article
Full-text available
Heterogeneous systems composed of hydrophobic nanoporous materials and water are capable, depending on their characteristics, of efficiently dissipating (dampers) or storing ("molecular springs") energy. However, it is difficult to predict their properties based on macroscopic theories-classical capillarity for intrusion and classical nucleation th...
Article
In this work a general thermodynamic grounds as well as experimental verification are given to demonstrate how a reversible wetting process of a liquid in nanopores provoked by a temperature variation can be used to develop systems with the necessary thermal expansion behavior. Thermal expansion coefficients of such nanoporous heterogeneous lyophob...
Article
Full-text available
Thermal energy storage (TES) has gained growing interest in the area of renewable energy due to its great potential for increasing the efficiency of concentrated solar power (CSP) plants. One of the central issues is the development of a working body with desirable properties, namely, thermal conductivity; heat capacity; density; price; availabilit...
Article
The paper presents first experimental evidence of pronounced electrification effects upon reversible cycle of forced water intrusion-extrusion in nanoporous hydrophobic materials. Recorded generation of electricity combined with high-pressure calorimetric measurements balances the energy equation of {nanoporous solid + non-wetting liquid} systems c...
Article
The Inside Back Cover illustrates fascinating properties of a new molecular spring. The spring, formed from a stable hydrophobic metal–organic framework (MOF) Cu2(tebpz), can store mechanical and thermal energy simultaneously upon intrusion of H2O molecules into the MOF pores under reasonable operational pressure. More information can be found in t...
Article
A new molecular spring formed by hydrophobic Cu2(tebpz) (tebpz=3,3',5,5'-tetraethyl-4,4'-bipyrazolate) Metal-Organic Framework (MOF) and water is presented. Proposed nanoporous heterogeneous lyophobic system (HLS) has exceptional properties compared to numerous reported systems of such type in terms of stability, efficiency and operational pressure...
Article
Full-text available
Stability of metal-organic frameworks is one of the central issues for their successful usage in an increasingly wide range of applications. Particularly Zeolitic Imidazolate Frameworks (ZIFs) are known for their high stability. Herein we use the two most stable representatives ZIF-8 and ZIF-67 to show that the concomitant effect of pressure and te...
Thesis
La thèse est consacrée à l’étude théorique et expérimentale des propriétés thermodynamiques et d'usage de Systèmes Hétérogènes de Lyophobes nanoporeux (SHL) et leurs dépendances en fonction de la température afin de déterminer les conditions optimales et accroître l'efficacité des dispositifs énergétiques à base de SHL. La thèse présente les résult...
Article
Negative Thermal Expansion (NTE) is the process in which a system decreases its size upon heating and increases it upon cooling. NTE effect is unusual and useful for a great number of practical applications in the fields of electronics, medicine, mechanics, etc… In this work NTE effect is experimentally investigated for three porous Heterogeneous L...
Article
Full-text available
Metal-organic frameworks (MOFs) and particularly their subclass – Zeolite Imidazolate Frameworks (ZIFs) – are used for a variety of applications including particularly energy. Highly porous MOFs mixed with non-wetting liquid can be used to form molecular springs (MS) for efficient mechanical and thermal energy storage/transformation. In this paper...
Article
Full-text available
Hydrophobic microporous metal-organic framework ZIF-8 combined with water forms molecular spring (MS), which by means of forced intrusion of water into the pores and its spontaneous extrusion can store and restore large amounts of mechanical and thermal energy. By means of scanning transitiometry technique we demonstrate that simultaneous effect of...