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Hydrogen is considered the energy source which can ensure the global transition to sustainable low-carbon energy systems. Municipalities can become more eco-friendly by adopting and implementing hydrogen-based energy systems. At the beginning of the transition toward carbon neutrality, the municipalities can use the hydrogen mixed with natural gas in the existing natural gas network for food and domestic hot water preparation, and heating and electricity generation, and the hydrogen stored as compressed gas, cryo-...

The transition to renewable energy sources is a key strategy for reducing carbon emissions and ensuring energy sustainability. This study explores the integration of photovoltaic (PV) systems for hydrogen production and storage in Constan?a County, Romania. The region benefits from high solar potential, making it an optimal location for implementing solar energy solutions. The proposed system converts solar energy into electricity through photovoltaic panels, which is then used to power an electrolyzer for hydroge...

This paper explores the operational characteristics of a DC islanded microgrid engineered to produce green hydrogen, utilizing power sourced from a solar array complemented by an energy storage system. The model simulates a one-week evaluation period, incorporating comprehensive analyses of electrical, thermal liquid, and thermal gas domains. By examining the interactions between the solar array, energy storage, and electrolyzer, the study provides a detailed assessment of system performance under varying conditio...

This paper presents an in-depth analysis of a residential solar thermal system designed for domestic hot water (DHW) production in a single-family dwelling located in Mangalia, Romania. Positioned at a latitude of 43.894- and a longitude of 28.422-, Mangalia benefits from an annual global irradiation of 1403 kWh/m?, providing favorable conditions for solar energy utilization. The study evaluates the system's performance over the course of a year, focusing on energy consumption, solar fraction, and environmental be...

Hydrogen-based energy production involves the use of fuel cells or the direct combustion of hydrogen (a particular case being hydrogen combustion in internal combustion engines). Direct hydrogen combustion is still in the testing phase, with challenges arising from its energetic properties, which continue to be a difficult factor. For instance, hydrogen has a low calorific value (about three times lower than methane) in its gaseous phase, which is the phase where combustion occurs, a very high combustion speed (ab...

The use of hydrogen as a fuel requires as much research as possible on the construction and functional parameters for the development of appropriate burners. The researches undertaken are addressed to diffuse flame burners with concentric jets of fuel and air. These burners cannot lead to flame return, the combustion being much safer, than for the case of burners with fuel-air mixture. The researches were carried out by numerical modeling through the ANSYS-FLUENT V.14.0 software. An important stage of the research...

In the energy field hydrogen will be more obvious to use by certain technologies than by direct combustion. The paper presents a conceptual analysis on the use of hydrogen by hydrogen by hydrogenation of carbon dioxide with final product methane, by hydrogenation of carbon dioxide, with the final product of methanol and by injection in certain proportions into the natural gas network. A new application of carbon dioxide hydrogenation is the decarbonisation of flue gases. To this end, conceptual analyses have been ...

Renewable resources? share in meeting the power balance in Romania grew constantly during the past decade. Therefore, the contribution of polluting energy sources (such as coal or oil) has progressively reduced. Moreover, to enable environmental impact mitigation for the still operating classical plants, proper desulphurization equipment were installed. It is remarked that the shares corresponding to hydro-energy and nuclear energy show an almost constant trend. Sensible investments were made in the energy sector,...

The topic addressed in this paper is related to two waste management (poultry manure) objectives: reducing environmental impact through combustion, and energy generation. Poultry industry waste is produced in large amounts and cannot be always used as a fertilizer. Its storage needs large sites, but if they are improperly designed could affect the phreatic groundwater. The paper is organized as it follows. The first part presents the energy characteristics the waste samples analyzed (they come from a poultry farm,...

This paper addresses the possibility of using poultry manure pyrolysis to obtain energy-efficient products. Poultry manure pyrolysis is the intended technology of combustion for both ecological and energy generation purposes, obtaining coke and gas fuel. The waste subjected to pyrolysis had a behaviour very close to that of the inferior coal. This is also confirmed by the elemental analysis; high moisture value raising issues when direct combustion is used. The combustion of the poultry manure through various tech...

Due to high quantities of animal fat resulted from leather industry, the necessity of a solution in order to neutralize the negative effects that appear by their discharge into the nature has led to continuous research in order to obtain the most suitable one for solving the environmental issue with energy recovery. Between combustion and chemical treatment, the combustion has been chosen in this study as being the most effective one, by technical and economical criteria. Before this combustion, there were perform...