The paper focuses on the thermal potential utilization of the geothermal resources from the Olt Valley (Romania, Calimanesti, Caciulata area). The three existing drills ensure low enthalpy geothermal water (92-95°C) having, at the exit of the wells, a high content of combustible gases. The equivalent hot water thermal potential-without the use of the combustible gases-is used for heating several spa hotels and for the heat supply system of the urban area. At present, the gases from the geothermal water, having a rich content of methane (88 %), are released into the atmosphere. The paper proposes a solution concerning a complete valorisation of the energy potential of this geothermal water, using heat pumps and a highperformance micro gas turbine cogeneration unit. We highlight that it is possible to extend the exploitation of the geothermal energy by a viable solution, via which the investment can be recovered in a short time. This work provides a solution in total accordance with the frame of the European Directives regarding the increase in energy efficiency, the use of the renewable resources and the environment protection.
The extinguish process using the water mist jet is one of the most efficient system for hydrocarbon flame accidentally developed. The environmentally friendly of the system is an important challenge. Both free jets characteristics are analysed in aim to have a quick suppression of the flame. The paper is focused on the geometrical shape of the cone realised by every jet (flame and water mist). On this basis the relative position of the jets is decisive in aim to obtain the desired effect. Experimental measurements were made, and the results are presented in the paper including the infrared temperature field. The experimental analysis allows to find the adequate angle between jets for the flame extinction. So, the optimum position of the water mist jet applied on the fire was found. A thermal flame extinguish efficiency evaluation is presented, too. The system is non pollutant and the damages are reduced.
Romania is one of the European countries that has a rich geothermal potential, the main uses of this resource being the spaces heating and thermal baths. Recently, concerns about increasing energy efficiency and limiting greenhouse gas emissions, have determined an increased attention to heating systems using geothermal water. These will play an important role in the future in developing sustainable energies and reducing the use of fossil fuels. The authors present a case study on a heating system in the city of Călimănești, initially using liquid fuel, which was modernized by using geothermal hot water for the preparation of the thermal agent. As geothermal water, with an initial temperature of 95°C, cannot be cooled below 50°C, the authors considered the possibility of using a heat pump to fully exploit the thermal potential of geothermal water, increase the capacity of the system and increase its energy efficiency. The implementation of the heat pump in the district heating system and the results expected to be obtained are discussed. It was considered that the heat pump works in parallel with the heating system, obtaining an increase in its capacity by approx. 60% and an increase in energy efficiency by approx. 30%.
The main objective of the present paper is to provide a visual investigation of the fire and water mist interference during the extinguish process. This kind of the experimental study for these processes is imposed by the phenomena complexity. The experimental study provides us the information of real behaviour of jets assembly in operation. On this way the physical theoretical model may by better conceived. The main test was focused on the concave shape of ceiling, which gives the better suppression of the flame. From the heat balance, of the studied case, the extinguish efficiency is obtained, the values being around 20%. From these values result that a lot of working agent is lost. That loss is related to the finest of the droplets in the liquid jet. The experimental tests give us the optimal angles between the two jets in aim to realise an efficient extinguish operation.
Hot parts of turbo engines as well as those working in extreme conditions in the metallurgical industry are subject to complex loads, leading to wear factors that sometimes work together: temperature, thermal shock, erosion, corrosion, sliding friction, etc. The paper presents the types of protective structures developed, techniques used, methods of testing, investigation and results. Protective materials used are from the class of ceramics such as M/MeCrAlY/ ZrO 2 ٠ Y 2 O 3 (CaO, MgO, CeO), Me/NiCrAlY/Y 2 O 3 -Yb 2 O 3 -GdO 3 -Nd 2 O 3 -ZrO 2 /ZrB 2 and other variants, as well as the type of complex alloys associated with Cu support. The techniques used for creating protection layers are EB-PVD coating or WIG welding. By tribological or extreme thermal testing on a facility design and made within INCAS, it was verified experimentally the basic properties of the protected structures. Stand tests made on real components, successfully validate the materials and technology solutions we designed.
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