• Energy Research
• 2021-2025close
• TR close
• Istanbul Technical University close

AbstractIn this study, a novel solar tower-based gas turbine-driven multi-generation plant is proposed and analyzed in detail with energy, exergy, economic, and environmental impact analysis. A multiobjective optimization is performed by incorporating all performance indicators simultaneously. The proposed plant consists of an intercooling-regenerative-reheat solarized gas turbine cycle as the primary power cycle of a multi-generation plant for the first time. Two organic Rankine cycles are used to utilize waste heat of intercooling section and exhaust of gas turbine. To produce the multi-generation products of power, cooling, industrial process heating, fresh water, floor heating, green hydrogen, domestic hot water, hot air for food drying, and greenhouse heating, power cycles are integrated with a multi-effect desalination, a double-effect absorption refrigeration cycle, an electrolyzer, a drying hot air unit, a greenhouse heater, and an industrial process heater. A rigorous parametric analysis is performed to reveal the effects of variations of decision variables on the plant performance. At the optimum conditions, energy efficiency, exergy efficiency, average unit product exergy cost, and emission savings values are determined as 57.23%, 40.7%, 0.08315 $/kWh, and 948.7 kg CO2/h, respectively. Moreover, proposed plant can produce 1962 kW power and 3.353 kg/h hydrogen in addition to other utilities with a system cost rate of 0.05134 $/s and 3226 kW exergy destruction rate.

AbstractIn this study, a novel solar tower-based gas turbine-driven multi-generation plant is proposed and analyzed in detail with energy, exergy, economic, and environmental impact analysis. A multiobjective optimization is performed by incorporating all performance indicators simultaneously. The proposed plant consists of an intercooling-regenerative-reheat solarized gas turbine cycle as the primary power cycle of a multi-generation plant for the first time. Two organic Rankine cycles are used to utilize waste heat of intercooling section and exhaust of gas turbine. To produce the multi-generation products of power, cooling, industrial process heating, fresh water, floor heating, green hydrogen, domestic hot water, hot air for food drying, and greenhouse heating, power cycles are integrated with a multi-effect desalination, a double-effect absorption refrigeration cycle, an electrolyzer, a drying hot air unit, a greenhouse heater, and an industrial process heater. A rigorous parametric analysis is performed to reveal the effects of variations of decision variables on the plant performance. At the optimum conditions, energy efficiency, exergy efficiency, average unit product exergy cost, and emission savings values are determined as 57.23%, 40.7%, 0.08315 $/kWh, and 948.7 kg CO2/h, respectively. Moreover, proposed plant can produce 1962 kW power and 3.353 kg/h hydrogen in addition to other utilities with a system cost rate of 0.05134 $/s and 3226 kW exergy destruction rate.

The fabrication of environmentally friendly, semi-transparent, high-performance and cost-effective inorganic solar cells has been the subject of recent extensive study. One area of study involves incorporating one-dimensional nanostructures and high quality transparent conductive layers into the conventional thin film solar cell systems. The objective of this particular investigation was, therefore, to construct such a structure by integrating Graphene-ZnO-Nanorods (NRs) hybrid structure into a conventional Cu2ZnSnS4 (CZTS) thin film solar cell architecture. The process involved synthesizing vertically-aligned ZnO NRs, coated with thin layers of SnO2 and CdS, on chemical vapor deposited graphene pre-coated glass substrates. Following the SnO2-passivation and CdS coating, vertically well-aligned ZnO NRs were then decorated with a 500 nm-thick layer of CZTS using a one-step thermal evaporation technique.This process led to the manufacture of a superstrate solar cell with SLG /Graphene/ZnO-NRs/CdS/CZTS/Ag device structure as an example of graphene's application in optoelectronic devices. To reveal the physical properties of the grown graphene and deposited CZTS thin films, they were subjected to various characterization techniques. The structural, chemical and optical analyses results showed the formation of a single-phase kesterite CZTS thin film with a copper-deficient composition and an optical band gap of 1.47 eV on glass substrate and single layer growth of graphene on Cu-foil substrate, which was subsequently successfully transferred onto glass substrates. Electrical measurements unveiled the existence of two different VCu point defects in CZTS with thermal activation energies of 45 meV and 180 meV. The manufactured superstrate solar cell exhibited a short-circuit current density of 9.34 mA/cm2, an open-circuit voltage of 390.6 mV, a fill factor of 17.2%, and an energy conversion efficiency of 0.63%. © 2023 Elsevier B.V.

The fabrication of environmentally friendly, semi-transparent, high-performance and cost-effective inorganic solar cells has been the subject of recent extensive study. One area of study involves incorporating one-dimensional nanostructures and high quality transparent conductive layers into the conventional thin film solar cell systems. The objective of this particular investigation was, therefore, to construct such a structure by integrating Graphene-ZnO-Nanorods (NRs) hybrid structure into a conventional Cu2ZnSnS4 (CZTS) thin film solar cell architecture. The process involved synthesizing vertically-aligned ZnO NRs, coated with thin layers of SnO2 and CdS, on chemical vapor deposited graphene pre-coated glass substrates. Following the SnO2-passivation and CdS coating, vertically well-aligned ZnO NRs were then decorated with a 500 nm-thick layer of CZTS using a one-step thermal evaporation technique.This process led to the manufacture of a superstrate solar cell with SLG /Graphene/ZnO-NRs/CdS/CZTS/Ag device structure as an example of graphene's application in optoelectronic devices. To reveal the physical properties of the grown graphene and deposited CZTS thin films, they were subjected to various characterization techniques. The structural, chemical and optical analyses results showed the formation of a single-phase kesterite CZTS thin film with a copper-deficient composition and an optical band gap of 1.47 eV on glass substrate and single layer growth of graphene on Cu-foil substrate, which was subsequently successfully transferred onto glass substrates. Electrical measurements unveiled the existence of two different VCu point defects in CZTS with thermal activation energies of 45 meV and 180 meV. The manufactured superstrate solar cell exhibited a short-circuit current density of 9.34 mA/cm2, an open-circuit voltage of 390.6 mV, a fill factor of 17.2%, and an energy conversion efficiency of 0.63%. © 2023 Elsevier B.V.

Exposure to gamma-rays is hazardous for humans and other living beings because of their high penetration through the materials. For this reason, shielding materials (usually lead, copper and stainless steel) are used to protect against gamma rays. This study’s objective was to prepare ceramic materials for gamma radiation shielding by using different natural bentonite clays. Gamma-ray attenuation performances of the prepared shielding materials at different thicknesses were investigated and evaluated for different gamma-ray energies from different standard point gamma radiation sources (251Am, 57Co, 137Cs, 60Co, and 88Y). The mass and linear attenuation coefficients of the prepared ceramics vary between 0.238 and 0.443 cm2 g−1 and between 0.479 and 1.06 cm−1, respectively, depending on their thicknesses. Results showed that these materials could be prioritized because of their evidential properties of gamma radiation protection in radiation applications.

Exposure to gamma-rays is hazardous for humans and other living beings because of their high penetration through the materials. For this reason, shielding materials (usually lead, copper and stainless steel) are used to protect against gamma rays. This study’s objective was to prepare ceramic materials for gamma radiation shielding by using different natural bentonite clays. Gamma-ray attenuation performances of the prepared shielding materials at different thicknesses were investigated and evaluated for different gamma-ray energies from different standard point gamma radiation sources (251Am, 57Co, 137Cs, 60Co, and 88Y). The mass and linear attenuation coefficients of the prepared ceramics vary between 0.238 and 0.443 cm2 g−1 and between 0.479 and 1.06 cm−1, respectively, depending on their thicknesses. Results showed that these materials could be prioritized because of their evidential properties of gamma radiation protection in radiation applications.

Illegal use of electricity is very common in cryptocurrency mining farms, as energy bills are the most important component of the cost of cryptocurrency production. In this case, it raises the issue of how to detect illegal cryptocurrency mining. Innovative approaches are needed to identify data centers that illegally mine cryptocurrencies. This study proposes the use of unique noise and/or harmonic features of cryptocurrency generating machines to detect illegal cryptocurrency mining farms. Within the scope of this study, the characteristic harmonics originating from the data centers were determined by performing field tests on the neutral line of the electrical grid. In this study, it has been shown that electricity distribution companies can detect illegal cryptocurrency data centers using potential illegal electricity by monitoring energy quality data. Legal permissions can be obtained easily for detailed examination and detection in cryptocurrency data centers of using illegal electricity. With the proposed innovative approach, the time taken to detect illegal cryptocurrency mining farms using illegal electricity is reduced.

Illegal use of electricity is very common in cryptocurrency mining farms, as energy bills are the most important component of the cost of cryptocurrency production. In this case, it raises the issue of how to detect illegal cryptocurrency mining. Innovative approaches are needed to identify data centers that illegally mine cryptocurrencies. This study proposes the use of unique noise and/or harmonic features of cryptocurrency generating machines to detect illegal cryptocurrency mining farms. Within the scope of this study, the characteristic harmonics originating from the data centers were determined by performing field tests on the neutral line of the electrical grid. In this study, it has been shown that electricity distribution companies can detect illegal cryptocurrency data centers using potential illegal electricity by monitoring energy quality data. Legal permissions can be obtained easily for detailed examination and detection in cryptocurrency data centers of using illegal electricity. With the proposed innovative approach, the time taken to detect illegal cryptocurrency mining farms using illegal electricity is reduced.