Article
Thermodynamics
Jiubing Shen, Siyuan Yan, Zhichao Li, Yanping Xiao, Niugao Tan
Summary: This research proposes a more efficient and compact BOG reliquefaction process for LNG-fueled ships by replacing external precooling cycle with BOG self-expansion precooling cycle. Among the three proposed processes, case 1 performs the best with all BOG entering the expander for self-expansion precooling.
APPLIED THERMAL ENGINEERING
(2021)
Article
Energy & Fuels
Sarun Kumar Kochunni, Kanchan Chowdhury
Summary: This study investigates the impact of precooling on the performance of reliquefiers in LNG carrier ships, comparing different precooling systems for efficiency. The reverse Brayton and Claude systems show improved exergy efficiency after precooling with transcritical CO2 cycle, with increases of 7.5% and 7.0% respectively.
JOURNAL OF NATURAL GAS SCIENCE AND ENGINEERING
(2021)
Article
Green & Sustainable Science & Technology
R. Morales-Ospino, A. Celzard, V. Fierro
Summary: Liquid hydrogen (LH2) has the highest storage density with no chemical reaction required, but it needs to be cooled to 20 K using energy-intensive refrigeration. LH2 storage results in the evaporation of LH2, known as boil-off, leading to process inefficiency and energy losses. This review discusses the definition, challenges, state-of-the-art, and recovery strategies to minimize hydrogen evaporation, including zero boil-off (ZBO), hydrogen reliquefaction, and compression solutions. The expertise gained in cryogenic storage for spacecraft has potential applications beyond the industry. Proper integration of reliquefaction systems with LH2 tanks and non-mechanical compressors for boil-off hydrogen offer attractive options for advancing LH2 logistics.
RENEWABLE & SUSTAINABLE ENERGY REVIEWS
(2023)
Article
Green & Sustainable Science & Technology
Shilin Li, Zhongchao Zhao, Zhengchao Chen, Weiqin Zeng, Huizhi Gong
Summary: This paper investigated an improved BOG reliquefaction system for LNG transportation and storage, exploring the most suitable scheme for different refrigerants. Through simulation and optimization, it was found that using mixed refrigerants in both high-temperature and low-temperature refrigeration subsystems could achieve the best performance. The results showed improvements in performance after optimization in all three cases, with optimized Case 3 achieving the best overall performance.
SUSTAINABLE ENERGY TECHNOLOGIES AND ASSESSMENTS
(2021)
Article
Thermodynamics
Haneul Mun, Hyeonchul Kim, Jinwoo Park, Inkyu Lee
Summary: This paper investigates the challenge of boil-off gas (BOG) reliquefaction in the intercontinental transport of liquefied natural gas (LNG) and proposes a novel system using liquid air. Two different process designs, low-pressure liquid air (LPLA) and high-pressure liquid air (HPLA), are introduced. The results show that using liquid air can significantly reduce the energy consumption for reliquefaction, and the proposed HPLA process is more economical than commercial processes.
ENERGY CONVERSION AND MANAGEMENT
(2022)
Article
Thermodynamics
Sarun Kumar Kochunni, Kanchan Chowdhury
Summary: The Reverse Brayton cycle using nitrogen is utilized to reliquefy boil-off gas in LNG storage tanks. To maintain efficient and safe operation of the system, flexibility in system parameters should be considered in the design stage to address degradation in compressor and turbine efficiencies. Adjusting compressor pressure ratios and utilizing methods such as variable frequency drives can help mitigate power input to the reliquefier.
Article
Thermodynamics
Mingyue Yan, Zhen Pan, Liyan Shang, Li Zhou, Jingxian Yu
Summary: In this study, improvements were made to three BOG reliquefaction systems for small LNG ships, aiming to address the problem of boil-off gas affecting transportation safety. The systems were simulated using Aspen Plus and optimized using a mathematical model in Matlab. The results showed that the improved single mixed refrigerant reliquefaction system had advantages in thermodynamic performance and economic analysis under a BOG mass flowrate of 350 kg/h.
JOURNAL OF THERMAL SCIENCE AND ENGINEERING APPLICATIONS
(2022)
Article
Energy & Fuels
Linda Barelli, Gianni Bidini, Michele Perla, Francesco Pilo, Lorenzo Trombetti
Summary: This paper evaluates the phenomenon of pressure build-up and discharge in small LNG tanks by applying a model and conducting flow and pressure measurements. The aim is to improve safety awareness and design ventilation systems to reduce flammable gas concentration.
Article
Thermodynamics
Parth Prajapati, Vivek Patel, Bansi D. Raja, Hussam Jouhara
Summary: In this study, a multi-objective optimization of the combined Brayton and inverse Brayton cycle is conducted to maximize specific work output and minimize thermal efficiency. The evolutionary heat transfer search optimization algorithm is used for the optimization. Multiple optimal solutions are obtained for the objective functions using a Pareto optimal curve. The sensitivity analysis reveals the conflicting nature between the objective functions, where increasing thermal efficiency leads to a decrease in specific work output and vice versa. The results provide insights for selecting operating parameters and analyzing the effects of various factors on work output and thermal efficiency.
THERMAL SCIENCE AND ENGINEERING PROGRESS
(2023)
Article
Thermodynamics
Saif Z. S. Al Ghafri, Fernando Perez, Ki Heum Park, Liam Gallagher, Liam Warr, Aaron Stroda, Arman Siahvashi, Yonghee Ryu, Sungwoo Kim, Sung Gyu Kim, Yutaek Seo, Michael L. Johns, Eric F. May
Summary: This study conducted experiments to measure BOG production and pressure change under various industrial conditions for LNG-like binary mixtures of methane and ethane. Three distinct stages of BOG evolution were identified and a new non-equilibrium model using the GERG-2008 equation of state showed good agreement with experimental data in the self-pressurisation and homogeneous stages but had limitations in the transient stage.
APPLIED THERMAL ENGINEERING
(2021)
Article
Energy & Fuels
Sungwook Choi, In Woo Son, Jeong Ik Lee
Summary: Gas Brayton cycles, especially the open-air and closed supercritical CO2 (S-CO2) Brayton cycles, have shown high efficiency and compact sizes for microreactors. This research compares the performances of the open-air and closed S-CO2 Brayton cycles at microreactor power range using polytropic turbomachinery efficiency. The optimization parameters for the cycle include maximum efficiency, maximum cycle specific work, and maximum of the product of both indicators. The results indicate that the S-CO2 power cycle should be designed and optimized to maximize the cycle specific work for commercial-scale application.
Article
Thermodynamics
Zhongdi Duan, Hongxiang Xue, Xueru Gong, Wenyong Tang
Summary: This study presents a non-equilibrium model to predict LNG boil-off in storage tanks, which is significant for tank design, BOG management and thermoeconomic assessment. The model shows that vapor superheating leads to additional loss during initial boil-off, while liquid natural convection enhances LNG evaporation and helps reduce total boil-off loss. The findings provide insights relevant to reducing BOG rate and total boil-off loss.
Article
Thermodynamics
Chendi Yang, Xiaopeng Zhang, Ning Zhang, Gaohong He, Junjiang Bao
Summary: This study addresses the trade-off between thermodynamic and economic performance of supercritical CO2 Brayton cycles through multi-objective optimization of cycle superstructures. The results show that the superstructures have advantages over traditional structures in terms of trade-off solution performance and structure selection.
ENERGY CONVERSION AND MANAGEMENT
(2022)
Article
Thermodynamics
Ryszard Bartnik, Tomasz Kowalczyk
Summary: The paper presents a novel hierarchical gas-gas system cooperating with compressed-air energy storage, analyzing it thermodynamically and economically. The study utilizes mathematical models to explore main thermodynamic and economic parameters, and identifies the optimal pressure ratio for the cycle.
ENERGY CONVERSION AND MANAGEMENT
(2021)
Article
Energy & Fuels
Shichang Yun, Dalin Zhang, Xinyu Li, Xuanang He, Wenxi Tian, Suizheng Qiu, G. H. Su, Quanbin Zhao
Summary: In order to exploit the advantages of Fluoride-Salt-cooled high-Temperature Advanced Reactors (FuSTAR), an energy conversion system based on a closed Brayton cycle was optimized for best parameters and configuration. The findings show that incorporating reheating into the system greatly enhances thermal efficiency. For different gases, specific configurations such as recompression intercooling or the incorporation of reheating, recompression, and intercooling can significantly improve thermal efficiencies.
Article
Thermodynamics
Ramon Ferreiro Garcia, Jose Carbia Carril, Javier Romero Gomez, Manuel Romero Gomez
ENERGY CONVERSION AND MANAGEMENT
(2016)
Article
Thermodynamics
Ramon Ferreiro Garcia, Jose Carbia Carril, Steven Iglesias Garcia
Review
Thermodynamics
Steven Iglesias Garcia, Ramon Ferreiro Garcia, Jose Carbia Carril, Denis Iglesias Garcia
ENERGY CONVERSION AND MANAGEMENT
(2017)
Article
Thermodynamics
Ignacio Arias Fernandez, Manuel Romero Gomez, Javier Romero Gomez, Luis M. Lopez-Gonzalez
ENERGY CONVERSION AND MANAGEMENT
(2017)
Review
Green & Sustainable Science & Technology
Ignacio Arias Fernandez, Manuel Romero Gomez, Javier Romero Gomez, A. Alvaro Baaliria Insua
RENEWABLE & SUSTAINABLE ENERGY REVIEWS
(2017)
Review
Green & Sustainable Science & Technology
Steven Iglesias Garcia, Ramon Ferreiro Garcia, Jose Carbia Carril, Denis Iglesias Garcia
RENEWABLE & SUSTAINABLE ENERGY REVIEWS
(2018)
Article
Energy & Fuels
Manuel Naveiro, Manuel Romero Gomez, Alvaro Baalina Insua, Maria Belen Folgueras
Summary: Energy, exergy, and economic analysis were conducted to evaluate regasification systems in FSRUs. The seawater regasification system was found to be the most efficient in terms of energy and exergy, while the open loop propane system was cost-effective for a certain range of LNG prices. There is a need to develop more efficient configurations to utilize the cold energy of LNG, as demonstrated by the excessive destroyed exergy in current systems.
INTERNATIONAL JOURNAL OF ENERGY RESEARCH
(2021)
Review
Engineering, Marine
Manuel Naveiro, Manuel Romero Gomez, Ignacio Arias Fernandez, Javier Romero Gomez
Summary: This paper reviews regasification technology in FSRUs and the potential of utilizing LNG cold energy. It discusses the characteristics and advantages of different regasification systems, highlighting the dominance of water-glycol systems in the market. It also suggests that utilizing cold energy in power cycles could significantly reduce emissions.
Article
Energy & Fuels
Manuel Naveiro, Manuel Romero Gomez, Ignacio Arias Fernandez, Alvaro Baalina Insua
Summary: This paper proposes design and operation indicators for the assessment of Floating Storage Regasification Unit (FSRU) energy efficiency and carbon footprint in order to reduce greenhouse gas emissions from the maritime sector. Five regasification systems were studied, with Case 1 proving the most energy efficient and Case 3 having the highest Energy Efficiency Design Index (EEDI).
JOURNAL OF NATURAL GAS SCIENCE AND ENGINEERING
(2021)
Article
Energy & Fuels
Manuel Naveiro, Manuel Romero Gomez, Ignacio Arias-Fernandez, Alvaro Baalina Insua
Summary: The present study provides an analysis of the energy, exergy, and economic aspects of a seawater regasification system that utilizes the cold energy of LNG. The proposed system, ORC-OC, combines stages of organic Rankine cycles (ORCs) with an open organic Rankine cycle (OC) to achieve zero greenhouse emissions during the regasification process. The results show that the two-stage ORC-OC configuration is more cost-effective, although the three-stage configuration achieves a slightly higher exergy efficiency. The study also suggests that if the excess electrical power is exported and compact heat exchangers are implemented, the overall cost rate could be further reduced.
Review
Thermodynamics
Doha Elrhoul, Manuel Romero Gomez, Manuel Naveiro
Summary: Maritime transport contributes 90% to international trade but heavily relies on fossil fuels, leading to greenhouse gas emissions. This article reviews shipboard methods for producing and using green hydrogen, such as solar and wind-based methods during the day. Energy recovery and the use of ammonia and hydrogen solids for storage are also discussed. Internal combustion engines are suitable for hydrogen fueling. Life-cycle assessment studies show that green hydrogen has a positive environmental impact despite its costliness.
INTERNATIONAL JOURNAL OF GREEN ENERGY
(2023)
Article
Energy & Fuels
Ramon Ferreiro Garcia
Summary: This work discusses a study on a disruptive design of a thermal power plant with multiple power units coupled in cascade to increase heat utilization factor. The study focuses on the pre-implementation phases of a heat-to-work converter prototype and analyzes its performance using vacuum cooling. A plant structure based on cascading coupling of three thermal cycles is proposed to achieve a high heat utilization factor.
Article
Engineering, Marine
Ignacio Arias Fernandez, Manuel Romero Gomez, Javier Romero Gomez, Luis M. Lopez-Gonzalez
POLISH MARITIME RESEARCH
(2020)
