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Investigation of the condensation process in the transient flow region in a biofuel plant condensing economizer model
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doc. dr. Robertas Poškas |
state-funded |
Research Topic Summary.
Lithuania has a well established network of biofuel boiler plants with innovative equipment to improve the efficiency of such boiler plants. One of these is the condensing economizer, which is used to improve boiler efficiency and recover waste heat. This heat exchanger reduces the amount of heat emitted to the environment through the stack with the flue gases, but increases the installation cost of the biofuel boiler plant. The cost of a condensing economizer is determined by its dimensions. To define the optimum size of the unit while maintaining the high efficiency of the heat exchanger, it is necessary to have a good understanding of the regularities of the complex heat and mass transfer processes that take place in the heat exchanger. Therefore, experimental studies of the condensation process in a shell and tube condensing economizer model with transient flow regimes are planned. Such studies would be carried out in collaboration with the Lithuanian Energy Institute.
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Numerical simulation of heat transfer in the case of natural circulation of coolant in nuclear installations
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prof. dr. Algirdas Kaliatka |
state-funded |
Research Topic Summary.
Nuclear energy can significantly contribute to the solution of the current energy problems in the EU and Lithuania, as it would positively contribute to security of supply, stability of energy prices and the achievement of carbon dioxide reduction goals. Therefore, research related to the safety of existing and new nuclear power plants remains relevant. Recently, special attention has been paid to passive cooling systems, which are installed in currently operating power reactors, and are also widely used in the construction of small modular reactors. In these passive cooling systems, the heat is removed by the natural circulation of the coolant. Natural coolant circulation also works in spent nuclear fuel storage facilities (for example, fuel storage pools and dry storage hermetic containers). However, this phenomenon has not been studied in as much detail as the forced circulation of the coolant. Natural circulation is characterized by small pressure (driving force) gradients and low coolant velocities. Also, the computer programs that are usually used to model the consequences of accidents in nuclear facilities are developed and tested to model the forced circulation of the coolant at relatively high pressures. Therefore, the aim of this work is the study of the natural coolant circulation in nuclear facilities and the assessment of the suitability of modeling with specialized computer programs.
The result of the PhD dissertation should be a study of the processes taking place in heat removal systems based on the natural circulation of the coolant and prepared recommendations for the modeling of these processes.
In this topic, several dissertation theses are possible, which will be agreed with PhD students, depending on the selected circulation systems, specific circulation modes, etc. It is also possible to analyze natural circulation in non-nuclear facilities.
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The models for technical and market analysis of customer connected hybrid energy systems
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prof. dr. Saulius Gudžius |
state-funded |
Research Topic Summary.
The transformation of the energy system, driven by the challenges of climate change and the desire to increase the efficiency of energy consumption and production, is facing problems that prevent it from achieving the needed security of energy supply and the strategic objectives of the energy system transformation. The most sustainable ways to address these problems are through the creation of new technical solutions based on a holistic approach to the energy system and the development of hybrid energy supply systems and their integrated management structures. Such technical structures can be applied to improve energy security and energy efficiency of both power systems and consumers [1,2]. The research focuses on the development and refinement of technical and market models and methodologies for the use of consumer hybrid energy systems in the provision of energy flexibility services either individually or as part of an energy community. The study consists of the following parts: 1. Development and refinement of technical and market analysis models for hybrid consumer-owned distributed generation, storage systems and loads potentially deployed in energy flexibility services. 2. Development of a methodology for characterising the operational parameters of the hybrid system and the characteristics of generation and energy consumption measurement systems that measure, transmit and store data at synchronised time intervals and volumes suitable for the provision of energy flexibility services.
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