<p>  </p> <p>Concentrated solar power (CSP) is a technology that utilizes focused sunlight to heat a high-temperature medium (such as a molten salt). Heat from this medium can be transferred to a working fluid (such as supercritical CO2) that is then used to drive a turbine to generate electricity. Alternatively, the hot medium/fluid can be pumped into tanks for thermal energy storage (TES), for heat extraction later to generate dispatchable electricity and/or for electricity production at night or on cloudy days. By increasing the fluid temperature to <u>></u>750oC and utilizing TES, CSP can become more cost competitive with fossil-based electricity production. Current CSP systems utilize molten nitrate salts for heat transfer and TES that are known to thermally degrade at temperatures >600oC. To achieve temperatures <u>></u>750oC, molten chloride salts, such as ternary MgCl2-KCl-NaCl compositions, are being considered as heat transfer and thermal energy fluids for next generation CSP plants due to their higher temperature stability, low cost, and availability. </p> <p>In this work, it was demonstrated that MgCl2-containing molten salts are prone to oxidation in ambient air at 750oC, which can enhance corrosion of the containment materials and alter the thermophysical properties of the fluid. An alternative, low-cost, earth-abundant, MgCl2-free, oxidation-resistant molten salt, a eutectic CaCl2-NaCl composition, was developed, along with a corrosion mitigation strategy, to enable the slow growth of protective oxide layers on metals that are resistant to dissolution by such MgCl2-free molten chloride salts. </p> <p>This strategy was expanded to other low-cost, oxidation resistant compositions, such as eutectic BaCl2-CaCl2-KCl-NaCl with tailored chemical and thermophysical properties for CSP and TES. The melting temperature, heat capacity, oxidation resistance, and crystallization behavior were measured for eutectic a BaCl2-CaCl2-KCl-NaCl(17.5-47.8-3.3-31.4 mol%) (BCKN) salt and a MgCl2-KCl-NaCl (40-40-20 mol%) salt. BCKN salt was shown to have a similar melting temperature while having a higher heat capacity and far better oxidation resistance. </p> <p>The corrosion of the nickel-based superalloy Haynes 214 was studied in molten MgCl2-KCl-NaCl (40-40-20 mol%) salt at 750oC under inert atmosphere conditions using a custom-built rotating-disc corrosion testing apparatus that maintained laminar fluid flow on the sample. Non-protective external Cr-, Al-, and Mg- oxide layers were formed on Haynes 214 that were prone to spallation. Internal oxidation of Al was also observed along with Cr depletion zones within Haynes 214.  Corrosion kinetics were evaluated to quantify the role of fluid flow for application of this alloy for use in containment and transportation of this molten chloride salt. </p>

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Sur un exemple concret d’entreprise française disposant des technologies innovantes dans les domaines du chauffage et de la distribution d’eau et ayant un projet d’expansion vers un nouveau marché, en l’occurrence, le marché russe, l’auteur montre l’importance de ces technologies pour accéder au marché fortement différent du marché domestique. Au sein du secteur du chauffage dans un pays où, à cause des conditions climatiques froides, le besoin de se chauffer présente un besoin vital, où le retard technologique dû au phénomène historique du monopole du chauffage central collectif est particulièrement ressenti et où le marché est en pleine formation avec la montée de la concurrence, les technologies nouvelles ont sans doute un rôle capital à jouer. Comment l’entreprise porteuse de ces technologies doit-t-elle aborder le marché russe certes très prometteur, mais fragile surtout en cette période délicate de la crise économique mondiale? Quels en sont les risques et les perspectives ? Comment réussir ce marché ? Comment mettre en valeur et transférer de nouvelles solutions technologiques ? Quels sont les avantages de ce transfert pour l’entreprise, mais également pour son partenaire local, pour la région visée et pour l’Etat receveur ? Telles sont les questions que l’auteur se pose. Le rôle des technologies nouvelles va certainement au-delà d’un secteur ou d’un domaine d’activité : les technologies nouvelles apportées par des entreprises occidentales ont sans doute accéléré, en ce qui concerne la Russie, le passage d’un système économique du type soviétique vers un système de libre-échange que l’on connait sous le terme d’économie de marché. / On a specific example of a French company having innovative technologies in the field of heating and water distribution, and realizing an expansion project to a new market, in this case, the Russian market, the author shows the importance of technologies when penetrating a market strongly different from the domestic one. Within the heating sector in the country where, because of a cold climate, the need to feel warm is a vital need, where the technological backwardness due to the historical phenomenon of the central residential heating monopoly is obvious, and where market is taking shape and competition is now growing, new technologies have without doubt a capital part to play. How should a company with such technologies approach the Russian market certainly very promising, but also fragile especially in this delicate period of the world economic crisis? What are the risks and the perspectives for the company? How to succeed in this market? How to enhance the value and to transfer new technological solutions? What advantages does this transfer bring to the company, but also to the company’s local partner, to the targeted region, and to the receiving country? These are questions the author asks himself. The role of new technologies is certainly beyond a sector or a field of activity: the new technologies brought by western companies undoubtedly accelerated, as Russia is concerned, the change from the Soviet-type economic system to a free-market system, known as the market economy.

The master Thesis deals with indirect air heating in air handling units. In the theoretical part of the thesis the categories of heat exchangers are defined according to their positioning in ventilation system, used material and type of heat transfer fluid. To the issue of calculating heat exchanges through heat exchangers and description of different kinds of regulation of primary heat transfer fluid is dedicated a separate chapter. The experimental part of the thesis deals with determining performance of current air heat exchanger at set thermal gradient with various heat transfer fluids. In the calculating part of the Thesis, based on measured values, are suggested two possible solutions for use of technological waste heat. Final evaluation of particular solutions was based on the criterion of efficiency usage and implementation investment costs.