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R. Imre, Attila
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R. Imre
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Attila
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Attila R. Imre
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A NOVEL APPROACH TO DISTRICT HEATING: USING A TWOPHASE EXPANDER IN REVERSIBLE HEAT PUMP-ORGANIC RANKINE CYCLE SYSTEMDaniarta, Sindu; R. Imre, Attila; Kolasiński, PiotrA district heating system involves a central generation and distribution of heat to residential buildings through a network of insulated pipes. Heat can be generated, for example, from the combustion of fossil fuels and biomass. Since there are many environmental restrictions and the growth of heat and energy demand, several industrial waste heat and renewable energy sources, such as geothermal or solar thermal energy may be promising to be utilized for district heating purposes. However, in some districts, various low-temperature heat sources might be available; as a result, a heat pump is installed to increase the temperature to accommodate demand peak loads. The heat pump is operated only for a certain period and sometimes not used during summer. To optimize the utilization of the heat source, the district heating system may be transformed into a power generation system that can generate, for example, electricity instead of heat during the summer. This goal may be achieved by applying a reversible system. Therefore, this article discusses the novel reversible heat pump-organic Rankine cycle (RHPORC) system using a two-phase expansion system. Some working fluids were selected based on thermal properties, as well as safety and environmental issues. Some selected two-phase volumetric expanders were introduced in the novel system. In the end, the performances of the system based on the selected working fluid were compared. According to the results of a study, using RHPORC in district heating systems might save annual energy consumption by up to 50%.- COST-EFFECTIVE OPTION OF COLD ENERGY UTILIZATION IN PHARMACEUTICAL INDUSTRYDaniarta, Sindu; Sowa, Dawid; Havas, Ádám; R. Imre, Attila; Kolasiński, PiotrIn pharmaceutical industries, nitrogen is used for several purposes, including inerting storage containers to prevent chemical reactions with oxygen at a temperature range of 2 to 8 °C. To meet these specifications, the regasification of liquefied nitrogen (LIN), transforming the liquefied nitrogen into gas phases at certain temperatures and pressures, is necessary. One potential solution that can be applied to increase efficiency and reduce costs while maintaining strict quality and safety standards in the pharmaceutical industry is a replacement of the conventional LIN regasification process with an organic Rankine cycle (ORC). This process could utilize cold energy from the process while using nitrogen as a cooling source and ambient air as the hot side of the thermodynamic cycle. Using the ORC system for this cold energy utilization is promising as the technology is now more developed, compact, relatively reasonable cost, and reliable. Since there are few investigations in cold energy utilization as power generation, this article discusses the techno-economic feasibility of the ORC system in the case of its application in pharmaceutical industries with a particular focus on cold energy utilization in LIN regasification. In this analysis, propane was selected as the working fluid of the ORC system as it has good criteria such as thermal properties, zero ozone depletion potential, and low global warming potential. The analysis was optimized for different heat source conditions. Several designs (with and without the direct expansion system) were developed. In the end, their techno-economic performances and cost-effectiveness were compared. The obtained results show that replacing the conventional LIN regasification in the pharmaceutical industry with an ORC system may improve the efficiency of the system and reduce power consumption. The results of the study additionally indicate that, in terms of cost-effectiveness, reusing existing components of the prior system – specifically, the nitrogen vaporizers and pump – would result in a 23.81% reduction in investment costs and a 22.00% decrease in levelized cost of energy (LCOE).
