Svetlana Ushak

On the new low-dimensional organic–inorganic hybrid solids Cu4(bipy)4[V4P2O19]·nH2O (n∼ 5) and Cu2(bipy)2[V2P2O12] with linear [V4P2O19]8− and cyclic [V2P2O12]4− oligomers

The new hybrid organic–inorganic copper oxovanadium phosphates of composition Cu4(bipy)4V4O11(PO4)2·nH2O (n ∼ 5) (1) and Cu2(bipy)2V2P2O12 (2) (bipy = 2, 2′-bipyridine) adopting the triclinic symmetry were obtained by soft hydrothermal routes. Both structures present different oxovanadium phosphate anionic units, resulting from the vertex-sharing of PO4 and VO4 tetrahedra, which are coordinated to copper diimine cationic groups to form a 1D framework. The VPO structures are reminiscent of the known connectivity and geometry of polyphosphate anions. For the two compounds, the magnetic copper(II) centres are square pyramidally coordinated with two nitrogen atoms of the neutral diimine ligand and three oxygen atoms of the oxovanadium phosphate subunit. The CuN2O3 pyramids are linked together by oxo-bridges involving PO4 tetrahedra in Cu2(bipy)2V2P2O12 with the closest Cu–Cu distances corresponding to 4.98 A. Edge-sharing of the copper pyramids in Cu4(bipy)4V4O11(PO4)2·nH2O results in the binuclear unit {Cu2O4N4}, with Cu–Cu distances of 3.19 A. Additional links of these dimers by phosphate oxo-bridges result in the formation of rectangular tetramers Cu4 with a copper–copper separation of approximately 4.10 A. Results of thermal analysis and magnetic susceptibility are presented.

Preparation and Characterization of Inorganic PCM Microcapsules by Fluidized Bed Method

The literature shows that inorganic phase change materials (PCM) have been very seldom microencapsulated, so this study aims to contribute to filling this research gap. Bischofite, a by-product from the non-metallic industry identified as having good potential to be used as inorganic PCM, was microencapsulated by means of a fluidized bed method with acrylic as polymer and chloroform as solvent, after compatibility studies of both several solvents and several polymers. The formation of bischofite and pure MgCl2·6H2O microcapsules was investigated and analyzed. Results showed an efficiency in microencapsulation of 95% could be achieved when using 2 min of fluidization time and 2 kg/h of atomization flow. The final microcapsules had excellent melting temperatures and enthalpy compared to the original PCM, 104.6 °C and 95 J/g for bischofite, and 95.3 and 118.3 for MgCl2·6H2O.

Prospects for photovoltaics in sunny and arid regions: A solar grand plan for Chile -Part I-investigation of PV and wind penetration

New markets for photovoltaics are being created in emerging economies where rich solar resources can produce solar electricity at affordable costs. A case in point is Chile, a country with great solar resources planning renewable energy deployment to address the needs of an expanding mining industry and a growing economy, while preserving the environment. The expansion of metal mining and smelting operations is constrained by the cost of electricity and the unavailability of water in northern Chile, offering an opportune synergy between photovoltaics and mining. Local estimates put the potential for solar electricity in the north interconnect at more than 200 GW, those of geothermal in the north and central interconnects from 3-16 GW, wind in the central interconnect from 5-40 GW, and small hydro and biomass in the south at 0.3 and 0.4 GW, correspondingly. These resources can supply not only the needs for sustainable development in Chile but can also produce electricity for neighboring countries. This paper examines the potential for immediate PV penetration in Chiles main electricity grids (SING and SIC) and options (i.e., curtailment, PV and wind combinations) that can increase such penetration.

3 – Using molten salts and other liquid sensible storage media in thermal energy storage (TES) systems

This chapter describes the principles of heat storage systems, with emphasis on sensible storage media on an industrial scale. This chapter provides information on both organic and inorganic commercial heat storage liquid media and discusses the advantages and disadvantages of each of these. Improvements in thermophysical properties of existing molten salts, such as heat capacity, thermal stability and thermal conductivity, are described. Also, the results of research into developing new low melting point molten salt mixtures and other promising sensible heat storage liquid media, such as metals, alloys and ionic liquids, are presented.

Industrial waste materials and by-products as thermal energy storage (TES) materials: A review

A wide variety of potential materials for thermal energy storage (TES) have been identify depending on the implemented TES method, Sensible, latent or thermochemical. In order to improve the efficiency of TES systems more alternatives are continuously being sought. In this regard, this paper presents the review of low cost heat storage materials focused mainly in two objectives: on the one hand, the implementation of improved heat storage devices based on new appropriate materials and, on the other hand, the valorisation of waste industrial materials will have strong environmental, economic and societal benefits such as reducing the landfilled waste amounts, reducing the greenhouse emissions and others. Different industrial and municipal waste materials and by products have been considered as potential TES materials and have been characterized as such. Asbestos containing wastes, fly ashes, by-products from the salt industry and from the metal industry, wastes from recycling steel process and from copper refining process and dross from the aluminium industry, and municipal wastes (glass and nylon) have been considered. This work shows a great revalorization of wastes and by-product opportunity as TES materials, although more studies are needed to achieve industrial deployment of the idea.A wide variety of potential materials for thermal energy storage (TES) have been identify depending on the implemented TES method, Sensible, latent or thermochemical. In order to improve the efficiency of TES systems more alternatives are continuously being sought. In this regard, this paper presents the review of low cost heat storage materials focused mainly in two objectives: on the one hand, the implementation of improved heat storage devices based on new appropriate materials and, on the other hand, the valorisation of waste industrial materials will have strong environmental, economic and societal benefits such as reducing the landfilled waste amounts, reducing the greenhouse emissions and others. Different industrial and municipal waste materials and by products have been considered as potential TES materials and have been characterized as such. Asbestos containing wastes, fly ashes, by-products from the salt industry and from the metal industry, wastes from recycling steel process and from copper ...