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Industrial processes are currently responsible for nearly 26% of European primary energy consumptions and are characterized by a multitude of energy losses. Among them, the ones that occur as heat streams rejected to the environment in the form of exhausts or effluents take place at different temperature levels. The reduction or recovery of such types of energy flows will undoubtedly contribute to the achievement of improved environmental performance as well as to reduce the overall manufacturing costs of goods. In this scenario, the current work aims at outlining the prospects of potential for industrial waste heat recovery in the European Union (EU) upon identification and quantification of primary energy consumptions among the major industrial sectors and their related waste streams and temperature levels. The paper introduces a new approach toward estimating the waste heat recovery in the European Union industry, using the Carnot efficiency in relation to the temperature levels of the processes involved. The assessment is carried out using EU statistical energy databases. The overall EU thermal energy waste is quantified at 920 TWh theoretical potential and 279 TWh Carnot potential.

In the European Industry, 275 TWh of thermal energy is rejected into the environment at temperatures beyond 300 °C. To recover some of this wasted energy, bottoming thermodynamic cycles using supercritical carbon dioxide (sCO 2) as working fluid are a promising technology for the conversion of the waste heat into power. CO 2 is a non-flammable and thermally stable compound, and due to its favourable thermo-physical properties in the supercritical state, can lead to high cycle efficiencies and a substantial reduction in size compared to alternative heat to power conversion technologies. In this work, a brief overview of the sCO 2 power cycle technology is presented. The main concepts behind this technology are highlighted, including key technological challenges with the major components such as turbomachinery and heat exchangers. The discussion focuses on heat to power conversion applications and benefits of the experience gained from the design and construction of a 50 kWe sCO 2 test facility at Brunel University London. A comparison between sCO 2 power cycles and conventional heat to power conversion systems is also provided. In particular, the operating ranges of sCO 2 and other heat to power systems are reported as a function of the waste heat source temperature and available thermal power. The resulting map provides insights for the preliminary selection of the most suitable heat to power conversion technology for a given industrial waste heat stream.

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This study aims to establish whether innovative food preservation technologies can offer significant reductions in energy consumption and corresponding greenhouse gas (GHG) emissions while delivering equivalent microbiological lethality, nutritional and organoleptic quality to conventional processes. The energy demand of high pressure processing, microwave, ohmic and conventional heating technologies, for achieving the same pasteurising effect in orange juice under commercially-representative processing conditions are measured and compared. The corresponding GHG emissions are evaluated using UK energy system emissions data, while the effect of equipment scale is explored empirically. The results show that for the same product quality, the innovative technologies are more energy-and non-renewable primary resource-efficient, with ohmic heating performing best, followed by high pressure

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