Sorin Dimitriu - Academia.edu (original) (raw)

Papers by Sorin Dimitriu

IntechOpen eBooks, Nov 25, 2022

Romania is one of the European countries that has a rich geothermal potential, the main uses of t... more 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%.

IOP Conference Series: Earth and Environmental Science, 2021

The extinguish process using the water mist jet is one of the most efficient system for hydrocarb... more 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.

English Abstract: Use the Carbon Dioxide extinguishing systems in the international maritime indu... more English Abstract: Use the Carbon Dioxide extinguishing systems in the international maritime industry are widely accepted and utilized as fire protection for various applications. The Carbon Dioxide is often used by fireman in fighting with disaster caused by fire. The carbon Dioxide is useful in situations in which water can’t be used.This work presents the study of the pneumatic time delay utilized in such installation. There are established the equations governing the filling process of the pressure accumulator and the dependence of the time delay in order to the initial conditions. There are shown the influences of the nozzle diameter, cylinder volume and the pressure and temperature from the piping manifold on the filling time. The result of this study is a simple method for setting cylinder volume and diameter of the nozzle fitted to the cylider in relation to the delay time desired. Romanian Abstract: Utilizarea sistemelor de stingere cu bioxid de carbon in industria navală i...

The paper presents a possible solution for increasing the efficiency of the centralized heating s... more The paper presents a possible solution for increasing the efficiency of the centralized heating systems. Romania possesses important geothermal resources. These may be utilized in conjunction with classical hot water boiler heating systems. The paper proposes a scheme to use the low enthalpy geothermal resources using a water vapours heat pump to increas the efficiency of a centralized heating system. Although water vapours are not an ordinary agent, due to this inconvenient, in certain conditions this natural agent represents an alternative to conventional solutions. A case study is presented.

IOP Conference Series: Materials Science and Engineering, 2019

The main objective of the present paper is to provide a visual investigation of the fire and wate... more 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.

In some geothermal fields, the hot water is associated with high content hydrocarbons gases, espe... more In some geothermal fields, the hot water is associated with high content hydrocarbons gases, especially methane. These gases, which can reach to a content of 2…2.5 m 3 N per cubic meter of water and can have a methane content of 85…90%, represent an important power potential. This paper presents the possibility of power potential recovery of these gases using gas engine cogeneration units. A case study is performed, regarding the geothermal water wells working in Calimanesti-Caciulata -Cozia zone, on the Olt Valley. An important power potential about 3,6 MW is pointed out, (1,4 MW electric power and 2,2 MW thermal power). The electrical energy can be locally consumed or injected in electrical public grid, while the thermal energy can be delivered to the zonal residential consumers.

International Journal of Energy and Environmental Engineering, 2014

The paper focuses on the thermal potential utilization of the geothermal resources from the Olt V... more 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 paper presents a possible solution for the increasing of the efficiency of the centralized he... more The paper presents a possible solution for the increasing of the efficiency of the centralized heating systems. Romania possesses important geothermal resources. These may be utilized in conjunction with the classical hot water boiler heating systems. The paper proposes a scheme to use the low enthalpy geothermal resources using a water vapours heat pump to increasing the efficiency of a centralized heating system. Although the water vapours are not an ordinary agent, due its inconvenient, in certain conditions this natural agent represents an alternative to conventional solutions. A case study is presented.

REZUMAT. Lucrarea tratează utilizarea metodei de analiza in infrarosu a câmpului de temperaturi d... more REZUMAT. Lucrarea tratează utilizarea metodei de analiza in infrarosu a câmpului de temperaturi dintr-un jet de ceaţă de apă. Elemente privind erorile de măsurare a temperaturii in infrarosu, comparativ cu metodele de măsurare directă, sunt prezentate in lucrare. Ca rezultat al acestui mod de evaluare a radiaţiei s-a obţinut caracteristica de emisivitate a mediului. A fost pusa in evidentă influenţa temperaturii, a umidităţii relative precum si a grosimii stratului dintre camera si obiectul vizat. Pe aceasta baza s-au obţinut parametrii de setare a camerei in funcţie de proprietăţile mediului. Testele au fost realizate pe un jet cald de lichid in evaporare, generat de un ajutaj convergent. Principala concluzie a lucrării o constituie faptul că metoda de măsurare a temperaturii in infrarosu trebuie corectată pe baza valorilor obţinute prin măsurătorile directe, in special in cazul mediului cu ceaţa. Pe această bază calculul fluxurilor de energie schimbate de obiectele sau mediile sup...

IntechOpen eBooks, Nov 25, 2022

Romania is one of the European countries that has a rich geothermal potential, the main uses of t... more 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%.

IOP Conference Series: Earth and Environmental Science, 2021

The extinguish process using the water mist jet is one of the most efficient system for hydrocarb... more 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.

English Abstract: Use the Carbon Dioxide extinguishing systems in the international maritime indu... more English Abstract: Use the Carbon Dioxide extinguishing systems in the international maritime industry are widely accepted and utilized as fire protection for various applications. The Carbon Dioxide is often used by fireman in fighting with disaster caused by fire. The carbon Dioxide is useful in situations in which water can’t be used.This work presents the study of the pneumatic time delay utilized in such installation. There are established the equations governing the filling process of the pressure accumulator and the dependence of the time delay in order to the initial conditions. There are shown the influences of the nozzle diameter, cylinder volume and the pressure and temperature from the piping manifold on the filling time. The result of this study is a simple method for setting cylinder volume and diameter of the nozzle fitted to the cylider in relation to the delay time desired. Romanian Abstract: Utilizarea sistemelor de stingere cu bioxid de carbon in industria navală i...

The paper presents a possible solution for increasing the efficiency of the centralized heating s... more The paper presents a possible solution for increasing the efficiency of the centralized heating systems. Romania possesses important geothermal resources. These may be utilized in conjunction with classical hot water boiler heating systems. The paper proposes a scheme to use the low enthalpy geothermal resources using a water vapours heat pump to increas the efficiency of a centralized heating system. Although water vapours are not an ordinary agent, due to this inconvenient, in certain conditions this natural agent represents an alternative to conventional solutions. A case study is presented.

IOP Conference Series: Materials Science and Engineering, 2019

The main objective of the present paper is to provide a visual investigation of the fire and wate... more 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.

In some geothermal fields, the hot water is associated with high content hydrocarbons gases, espe... more In some geothermal fields, the hot water is associated with high content hydrocarbons gases, especially methane. These gases, which can reach to a content of 2…2.5 m 3 N per cubic meter of water and can have a methane content of 85…90%, represent an important power potential. This paper presents the possibility of power potential recovery of these gases using gas engine cogeneration units. A case study is performed, regarding the geothermal water wells working in Calimanesti-Caciulata -Cozia zone, on the Olt Valley. An important power potential about 3,6 MW is pointed out, (1,4 MW electric power and 2,2 MW thermal power). The electrical energy can be locally consumed or injected in electrical public grid, while the thermal energy can be delivered to the zonal residential consumers.

International Journal of Energy and Environmental Engineering, 2014

The paper focuses on the thermal potential utilization of the geothermal resources from the Olt V... more 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 paper presents a possible solution for the increasing of the efficiency of the centralized he... more The paper presents a possible solution for the increasing of the efficiency of the centralized heating systems. Romania possesses important geothermal resources. These may be utilized in conjunction with the classical hot water boiler heating systems. The paper proposes a scheme to use the low enthalpy geothermal resources using a water vapours heat pump to increasing the efficiency of a centralized heating system. Although the water vapours are not an ordinary agent, due its inconvenient, in certain conditions this natural agent represents an alternative to conventional solutions. A case study is presented.

REZUMAT. Lucrarea tratează utilizarea metodei de analiza in infrarosu a câmpului de temperaturi d... more REZUMAT. Lucrarea tratează utilizarea metodei de analiza in infrarosu a câmpului de temperaturi dintr-un jet de ceaţă de apă. Elemente privind erorile de măsurare a temperaturii in infrarosu, comparativ cu metodele de măsurare directă, sunt prezentate in lucrare. Ca rezultat al acestui mod de evaluare a radiaţiei s-a obţinut caracteristica de emisivitate a mediului. A fost pusa in evidentă influenţa temperaturii, a umidităţii relative precum si a grosimii stratului dintre camera si obiectul vizat. Pe aceasta baza s-au obţinut parametrii de setare a camerei in funcţie de proprietăţile mediului. Testele au fost realizate pe un jet cald de lichid in evaporare, generat de un ajutaj convergent. Principala concluzie a lucrării o constituie faptul că metoda de măsurare a temperaturii in infrarosu trebuie corectată pe baza valorilor obţinute prin măsurătorile directe, in special in cazul mediului cu ceaţa. Pe această bază calculul fluxurilor de energie schimbate de obiectele sau mediile sup...