Rankine Cycle Research Articles

Thermal stability of MDM and oxidative decomposition mechanism under the condition of air infiltration: A combined experimental, ReaxFF-MD and DFT study

When siloxanes are used as the working fluids of organic Rankine cycle systems, there is a possibility of air infiltration due to the large vacuum present in the condenser. To address this issue, experimental and simulation studies were conducted on the thermal stability and pyrolysis product characteristics of octamethyltrisiloxane (MDM) in the presence of air. The results indicated that air significantly promotes the decomposition of MDM at the temperatures above 250 °C. Air was helpful in increasing the formation of CH2O, CO, and CO2, and also enhanced polymerization of decomposition product of siloxane, leading to higher yields of MD2M, MD3M, MD4M, D3, D4, and D5. By combining reactive force field molecular dynamics (ReaxFF-MD) simulations with density functional theory (DFT) calculations, the microscopic mechanisms of MDM's oxidative decomposition by O2 in air and H2O under humid conditions were elucidated. O2 can easily combine with unsaturated Si atoms to form Si-O bonds, combine with CH3 radicals to form C-O bonds, and undergoes hydrogen extraction reactions to initiate decomposition. H2O mainly undergoes initial decomposition through CH3 radical hydrogenation and binding with unsaturated Si atoms. The generated O2H, O, and OH radicals tend to bind with Si atoms in molecules and radicals, facilitating polymerization reactions.

Design of multi-cycle organic Rankine cycle systems for low-grade heat utilisation

Organic Rankine cycles (ORCs) facilitate the utilisation of low-grade heat sources (e.g., geothermal and industrial waste heat) for power generation, thereby improving energy efficiency in industrial processes and expanding the application of renewable energy. Using multiple ORCs instead of a single cycle provides more flexibility in heat integration and can increase the power output. This paper presents a mathematical model for designing multi-ORC systems; the design task involves the determination of ORC configurations and operating conditions whilst synthesising the associated heat exchanger network. Two case studies on geothermal and industrial waste heat ORC applications illustrate the developed optimisation formulation. In the geothermal case study, the maximum net power output for a single regenerative n-butane cycle can increase by 11.2 % as a result of optimising the ORC operating conditions. With two independent n-pentane cycles, a 7.6 % increase in the maximum net power output can be reached by optimising the ORC configurations. In the industrial waste heat case study, a 14.3 % increase in the maximum net power generation is found with a second n-butane cycle, and a further 5.7 % increase with a third. For comparison, the total annual cost and the payback period are also calculated in both case studies.

Multi-variable optimization of a geothermal power plant integrated with water electrolyzer and methanol production

Renewable energy-based routes for methanol generation are recognized as essential strategies for eco-friendly energy conversion. Thus, the current study focuses on developing an innovative combined energy system for methanol production using direct carbon dioxide hydrogenation powered by geothermal energy. This is important because it addresses the need for sustainable and environmentally friendly methods of methanol production while also harnessing the potential of geothermal energy as a renewable resource. Therefore, in order to achieve multigeneration energy production, this work introduces and optimizes a novel configuration that benefits from an innovative heat design process. This configuration integrates an organic Rankine cycle, a single-flash geothermal power plant, an ammonia-water absorption chiller, a proton exchange membrane electrolyzer, and a methanol generation unit. Using the Aspen HYSYS tool, the multigeneration energy system is modeled and analyzed. As a result, the system is assessed using energy, exergetic, environmental, and economic evaluations. Furthermore, performance evaluations are carried out in the following modes: single generation, multigeneration, cooling, heat and power generation, and cooling. Furthermore, a genetic algorithm is employed to optimize the system in terms of economy and exergy. The energy and exergy efficiency are determined to be 32.57 % and 76.3 %, respectively, under the base case results. Furthermore, the rate of overall costs is 377.38 $/h. Furthermore, the precise output of carbon dioxide is −0.043 kg/kWh. The optimal unit cost and exergy efficiency for all items, taking into account the optimization scenario, are 3.34/GJ and 78.35 %, respectively. In addition, the optimum carbon dioxide and hydrogen rates for methanol generation are 92.49 mol/h and 200.51 mol/h, respectively.

Comprehensive assessment and energetic-exergetic performance optimization of a new solar thermal electricity system based on Scheffler-type receivers combined with screw-type volumetric machines

This study explores the potential of a novel solar-powered cascade Rankine cycle system based on Scheffler-type receivers combined with screw expanders. Specifically, in this solar power system, steam is generated in the Scheffler-type receiver, which proves to be well performing compared with other technological solutions to exploit solar energy, due to satisfactory efficiency of the focal receiver that is able to curtail heat losses, even at high evaporation temperatures. Subsequently, steam expands in the screw machines which, unlike conventional steam turbines, are specially fitting in energy conversion with vapor-liquid mixes in the field from tens to hundreds of kW. In the present study, comprehensive assessment of this renewable energy power system is thoroughly conducted in a large range of operating states. For this purpose, specific numerical models and basic criteria fixed for the screw expanders and Scheffler receivers part-load behavior are combined with thermodynamic formulations established for energetic-exergetic performance optimization of the entire solar thermal electricity plant. Hence, parametric optimization of the major thermodynamic factors involved at part-load operating situations is conducted to enhance the energetic and exergetic efficiencies of the designed solar thermal power system.

Modeling of an advanced renewable energy system coupled with hydrogen production and liquefaction for sustainable communities

The primary objective of this study is to develop a sustainable and efficient renewable energy-based multigeneration system that is specifically designed to meet diverse energy demands, such as heat, cooling, electricity and hydrogen. The system comprises several subsystems: a digester for biomass processing, a solar energy collection system, a thermal energy storage system, a multistage Brayton cycle, a steam Rankine cycle with reheat, a double-effect absorption system, a sonic hydrogen production unit, and a multistage hydrogen liquefaction system. The methodology involves conducting energy and exergy analyses, economic evaluation, and environmental impact assessment to determine the system's performance and viability. The energy efficiency results show that the Brayton cycle, steam Rankine cycle and liquefaction system have efficiencies of 30.92 %, 30.18 %, and 64.53 %, respectively. The exergy efficiencies for these subsystems are 50.10 %, 67.21 %, and 11.29 %, respectively. The double-effect absorption system exhibits energetic and exergetic coefficients of performance of 1.68 and 0.64, respectively. The overall energy and exergy efficiencies of the system are 36.41 % and 55.74 %, respectively. The economic analysis indicates a significant revenue potential, with the project reaching its break-even point in 2031 and achieving a net present value of $6.60 million. The results of an environmental impact assessment study highlight a reduction in CO2 emissions compared to conventional systems, emphasizing the system's contribution to sustainable energy solutions.

Towards the dual heat sources recovery applied by organic Rankine cycle: An experimental assessment

The organic Rankine cycle (ORC) is a potential methodology for the thermal-power conversion of renewable energy (geothermal, solar, etc.). Towards the energy integrated application, the single heat source driven ORC could not satisfy the industrial development. In this work, a R1233zd(E)-based ORC driven by dual heat sources has been experimentally studied, and the dynamic system characteristics were primarily carried out. Considering the higher-temperature heat source with 100 °C–130 °C and the lower-temperature heat source with 55 °C–85 °C, the behaviors of the devices are evaluated, and the overall system performance are compared. After that, the comprehensive analysis on the effect of heat source temperatures is developed from the energy and exergy aspects. The results show that the net output and thermal efficiency mostly depend on the higher-temperature heat source. Both of the increasing temperature of the two heat sources would contribute to the enhancement of exergy efficiency, due to the increase in net output and the decrease in exergy loss, respectively. The contribution of the coordinate of the two heat sources are highlighted. Considering the combinations of heat sources with 130 °C/55 °C, 100 °C/55 °C,100 °C/85 °C, 130 °C/85 °C, the thermal efficiencies are sequentially 9.19 %–8.26 %, 7.24 %–6.98 %, 7.38 %–7.35 %, 8.83 %–8.29 %, and the exergy efficiencies are 13.03 %–11.80 %, 10.59 %–10.27 %, 12.12 %–11.98 %, 13.82 %–13.16 % in sequence.

Development and comprehensive analyses of a hybrid solar–geothermal driven polygeneration system: Thermodynamic, exergoeconomic, and emergoenvironmental aspects

The present research proposed an innovative polygeneration system that uses solar, geothermal, and natural gas energy to produce power, heat, steam, and freshwater. The system consists of a proton exchange membrane fuel cell, an organic Rankine cycle, and a multi-effect thermal desalination system. The study included thermodynamic, exergy, exergoeconomic, exergoenvironmental, emergy-based exergoeconomic, and emergy-based exergoenvironmental factors in its comprehensive evaluation of the system. Results underscored the financial aspect of the organic Rankine cycle and cogeneration system, incurring costs of 0.4518 $/s and 1.054 $/s respectively, while also highlighting the system's capability to produce 6 kg/s of freshwater. The environmental impact rates were quantified for the organic Rankine cycle and cogeneration system at 0.1417 and 0.4814 pts/s respectively, situating the system within its ecological context. Further, the study detailed the total efficiency and net power output of the organic Rankine cycle and cogeneration system, ranging between 32.45–33.51% and 43.25–45.83% for efficiency, and 56956–56322 kW and 50174–51898 kW for net power output r espectively, showcasing the system's operational capacity. A parametric analysis was also integral to the study, examining the impact of key parameters on the functionality of the proposed system, thereby providing a nuanced understanding of the system's performance under varying operational scenarios.

Hybridization of Concentrated Solar Thermal With Geothermal and Biomass Power

While Geothermal Power Plants (GPPs) can be a reliable renewable energy source, this reliability can decrease over the years due to brine mass flow declining. This reduced mass flow causes extra capacity unused in the GPP turbines. This problem can be overcome by hybridizing GPPs with CST and biomass. These three thermal technologies can, in theory, complement each other if all the resources are present at the exact location. This is the scenario for this study, as the location for the case study is the Kızıldere 2 (KZD2) GPP in Denizli, Turkiye, operated by Zorlu Energy. This region has sufficient potential for all three technologies: CST, geothermal, and biomass. Furthermore, by building a topping cycle using CST and biomass, it is possible to generate additional power. This study utilizes a topping steam Rankine cycle run equally by CST and biomass, and, as a result, the 20% excess capacity in the GPP turbine is used while generating an additional 20 MWe of power.

Hybrid solar-biomass residential micro – Combined Heat and Power systems driven by the Partially Evaporating Organic Rankine Cycle – A case study in Southern Europe

In this study, a novel hybrid solar-biomass residential micro – Combined Heat and Power system driven by the Partially Evaporating Organic Rankine Cycle is proposed and its operation is simulated, by applying an in-house numerical model. The simulation tool is applied for a test case in Athens, Greece, where the micro-CHP system operates to cover the annual energy demand of a multi-family building. The proposed cogeneration unit covers 97.10 % and 25.85 % of the modeled building’s annual Space Heating and electricity demand, respectively, by using renewable energy sources. The annual average total energy and exergy efficiencies are equal to 53.33 %, and 10.35 %, respectively, while the power cycle can achieve thermal efficiencies as high as 9.73 %. Competitive Levelized Cost of Electricity (0.072–0.133 €/kWhel), and Levelized Cost of Heat (0.036–0.067 €/kWhth) values are estimated, with a PayBack Period between 5.17 and 9.64 years. The environmental impact of the proposed hybrid micro-CHP is anticipated to be significant, rising to 46.25 kWh of Primary Energy Savings, and 31.22 kg CO2-eq. reduction in carbon emissions per m2 of residence annually.

Operational characteristics and performance optimizations of the organic Rankine cycle under different heat source/condensing environment conditions

The fluctuating heat sources and seasonal condensing environments are critical to the operation of Organic Rankine Cycle (ORC) under off-design conditions. This paper presents a comprehensive steady-state mathematical model developed using a newly built experimental platform. Focusing on the operational characteristics, including the evaporation pressure, condensation temperature, mass flow rate, and the performance of key equipment during the regulation of the expander, working fluid pump, and cooling water pump. Results show that the net efficiency initially increases before decreases, with both evaporation pressure and mass flow rate rising alongside the working fluid pump frequency. The quasi-two-stage single screw expander achieves an isentropic efficiency above 65 %. Additionally, flexible adjustments to the cooling water pump effectively regulate the cooling system, with timely cleaning of cooling pipelines enhancing net efficiency by up to 3.27 %. Optimization using the particle swarm algorithm improves system performance, achieving net efficiency enhancements of 1.8 % and 12.3 % under specific conditions. The novelty of this study lies in directly regulation of the expander, working fluid pump, and cooling water pump, significantly enhancing the off-design performance. This research provides valuable insights for researchers and designers, enabling flexible regulation of ORC operations to ensure efficient performance under varying conditions.

Economic Analyses of a New Power and Cooling System at Low Temperature Applications

Recent research suggests that the implementation of more efficient combined cooling and power systems, which enable the cogeneration of electricity and cooling, can enhance the efficiency of hybrid plants. The present investigation is motivated by finding that, in the literature review on combined power and cooling systems, there is very limited information on the coupling of the organic Rankine cycle (ORC) and the ejector refrigeration cycle (ERC) with low sink temperatures. A suggested approach to do this involves using hot exhaust gas and waste heat engines to power an ORC hybrid system. To enhance the ORC–ERC system's performance, three heater configurations use waste heat from the ORC turbine exhaust, ejector, and engine waste heat to heat the working fluid. Renewable energy sources are the primary focus of most current research initiatives. The present research focuses on unique ORC and ERC systems, considered as combined power and cooling systems, with the goal of improving exergy performance at low temperatures. The suggested ORC–ERC can generate energy destruction of 69.85 kW at a source temperature of 155 °C, with an exergetic efficiency of 76.9% at the turbine. Setting the entrainment ratio at 0.5 results in a total sum unit cost of products (SUCP) of 465 $/kW‐h for the ORC–ERC. Furthermore, the 37.83% exergy destruction ratio introduces heat exchanger 2 (HE2) as the primary cause of the suggested ORC–ERC's irreversibility. A detailed parametric study reveals that altering the hot source temperature and entrainment ratio improves the system's SUCP. The current examination at high sink temperatures may be expanded to an advanced exergoenvironmental investigation.

Fluorobenzene as new working fluid for high-temperature heat pumps and organic Rankine cycles: Energy analysis and thermal stability test

Industrial high-temperature heat pumps and Organic Rankine Cycles play a pivotal role in reducing CO2 emissions of the industrial sector. While several eco-friendly refrigerants have been explored for subcritical heat pumps below 150 °C, above this threshold only a few fluids can be adopted.In this article, fluorobenzene (C6H5F) is proposed for the first time as a versatile working fluid suitable for both HTHP and ORC systems. Notably, it possesses a near-zero Global Warming Potential, null Ozone Depletion Potential, low cost, and low toxicity. The thermo-chemical stability of fluorobenzene is experimentally investigated with an advanced procedure, simulating the presence of the non-condensable-gases removal system in real plant operating conditions. The yearly rate of unimolecular decomposition is estimated less than 4 % at 350 °C, and even after 400 h of thermal stress no decomposition products have been detected in the liquid phase through Fourier Transform Infrared Spectroscopy.In a direct heat exchange case study, coupled with exhaust gases at 390 °C, fluorobenzene achieves a net power production higher than other commercial fluids adopted in high-temperature units. In subcritical two-stage throttling heat pump condensing at 180 °C fluorobenzene shows a good Coefficient of Performance of 3.25 at 100 °C temperature lift.

Thermal Efficiency Analysis of a 1 kW ORC System with a Solar Collection Stage and R-245fa Working Fluid: A Case Study

A thermal efficiency analysis of an organic Rankine cycle (ORC) system enables its performance to be evaluated; for this purpose, critical system components, including the turbine and the boiler, must be scrutinized. ORC plants can operate under various regimes, such as simple, regeneration, and reheat work modes. Organic fluids such as R-245fa integrate low-temperature sources such as solar radiation. However, a literature review revealed limited research on the impact of a solar collection system on the overall thermal efficiency of an ORC system during the regeneration stage. In this study, we examined the thermal efficiency behavior of an ORC plant with a 1 kW generator operating in simple and regeneration modes with a solar collection stage. The results show that the thermal efficiency in simple mode was 35.27%, while in regeneration mode with solar collection it reached 51.30%. Improving the thermal efficiency of a thermodynamic cycle system can reduce CO2 emissions. The operating temperature ranges facilitate the development of a methodology for industries to implement ORC systems in their manufacturing processes, thereby utilizing waste heat from industrial operations.

Thermodynamic analysis of an advanced adiabatic compressed air energy storage system integrated with a high-temperature thermal energy storage and an Organic Rankine Cycle

Advanced adiabatic compressed air energy storage (AA-CAES) system has drawn great attention owing to its large-scale energy storage capacity, long lifespan, and environmental friendliness. However, the performance of the air turbine during the discharging process is limited by the low temperature of the compression heat. Thus, this study proposes an integrated AA-CAES system incorporating high-temperature thermal energy storage and an Organic Rankine Cycle (ORC). The high-temperature thermal energy storage is introduced to heat the discharging compressed air to enhance the air turbine performance, and the Organic Rankine Cycle is integrated to utilize the waste heat. Notably, two preheaters are deployed in a special tandem to recover the heat from the air exiting the turbine and the water exiting the hot water tank, respectively. This paper develops a thermodynamic model to simulate the proposed system, assessing the effects of heat storage temperature, ambient temperature, and inlet conditions of the air turbine on performance metrics, including exergy efficiency and exergy destruction. The simulation results indicate that, compared to thermal oil and Hitec salt, employing solar salt as the heat storage medium for the solar thermal collection and storage unit yields the best performance. The energy storage efficiency, roundtrip efficiency, exergy efficiency, exergy conversion coefficient, and energy storage density of this system are 115.6 %, 65.7 %, 78 %, 79.4 %, and 5.51 kWh/m3, respectively. Exergy analysis reveals that the exergy efficiency of interheaters (IH) is the lowest at 76.7 %, while air turbines (ATBs) exhibit the highest exergy efficiency at 91.2 %. Moreover, due to the irreversible processes of compression, expansion, and throttling, ATBS, compressors, and throttle valves collectively contribute to an exergy destruction rate as high as 79.2 %. The parameter analysis demonstrates that low ambient temperature, high inlet temperature, and high inlet pressure of the air turbine enhance energy storage performance.

Optimizing trigeneration energy systems: Biogas-centric methanol production via direct CO2 hydrogenation with advanced integration of PEM electrolyzer and LNG cold technology

Biogas, a sustainable alternative to fossil fuels, addresses issues of non-renewability and accessibility. Its structural similarity to fossil fuels makes it a potent option for energy systems. With this in mind, this paper discusses a novel trigeneration system that utilizes biogas and Liquefied natural gas cooling to produce methanol, electricity, cold water, hot water, oxygen, and natural gas. The system integrates various components such as a biogas burner, Kalina cycle, organic Rankine cycle, liquefied natural gas liquid gasification cycle, proton exchange membrane electrolyzer, and methanol synthesis unit. Simulation via Aspen HYSYS software includes an analysis of energy, exergy, economic, and environmental aspects. Efficiency assessment in single generation, cogeneration, trigeneration, and chemical trigeneration modes concludes chemical trigeneration as most efficient, with the proton exchange membrane electrolyzer being the most efficient subsystem. Key variables like Kalina cycle evaporator temperature, gas flow rate to the methanol reactor, and organic Rankine cycle working fluid pressure are assessed. Predictions on thermodynamic, environmental, and economic behaviors, along with their fluctuations, are made. Using a thermoeconomic approach, the economic analysis determines an exergy unit cost of 59.79 $/GJ and a total cost rate of 2764 $/h. Overall, this work presents a novel and efficient chemical trigeneration system that utilizes biogas and LNG cooling to produce multiple products.

Development and assessment of an integrated multigenerational energy system with cobalt-chlorine hydrogen generation cycle

This study aims to develop and assess a new multigeneration system where nuclear heat is utilized as the energy source. The multigeneration system is further designed to generate power, cooling, freshwater and hydrogen. In the present multigeneration system, five main subsystems, including high-temperature gas-cooled pebble bed nuclear reactors, a Rankine cycle, a cobalt-chlorine thermochemical cycle, a multi-effect desalination system and an ammonia-water absorption refrigeration system are integrated for synchronized operation. The analyses of the present system are carried out with the approaches of energy and exergy. This integrated system uses a total of 1000 MW thermal energy that is obtained from four units of high-temperature gas-cooled pebble bed nuclear reactor. Using all the thermal energy that comes from the nuclear reactors, a total of 346.99 MW of electricity, a total of 1.59 MW of cooling, a total of 384.67 kg/s of freshwater, and a total of 0.25 kg/s of hydrogen are produced. The energetic and exergetic performance coefficients of the ammonia-water absorption refrigeration system are 0.74 and 0.83, respectively. While the energy efficiency for the overall system is calculated as 37.83%, the exergy efficiency is found to be higher as 46.32% with the multiple useful outputs which help exergetically improve the overall system.

Design and analysis of a single-stage supersonic turbine with partial admission

Supersonic impulse turbines are commonly used to harvest waste heat from systems based on organic Rankine cycles, automotive applications, and gas-generator liquid rocket engines. This research aims to design and analyze a single-stage supersonic turbine with a rated power of approximately 440 KW. We present a comprehensive preliminary design roadmap followed by design parameters optimization. The preliminary sizing is carried out using one-dimensional flow analysis, while the blade geometrical design is performed using the two-dimensional method of characteristics. The turbine performance is then analyzed through numerical simulations on three-dimensional models. Comprehensive parametric analyses are conducted to examine the turbine performance sensitivity to changes in partial admission (PA), mean radius, and turbine blade height using three-dimensional sliding mesh techniques (SMT). The current analysis simulates the full turbine to capture PA effects, rather than focusing on a single periodic sector as is common in turbomachinery simulation practices. Different PA scenarios are investigated, emphasizing a single rotor passage over a complete rotor cycle in a partially admitted turbine, and examining its charging and discharging mechanisms. Flow tracking over such a blade shows that the turbine rotor exhibits compressor-like behavior over most of the unadmitted zone, contributing to efficiency drops and severe transients.

Thermodynamic analysis and optimization of the TI-PTES based on ORC/OFC with zeotropic mixture working fluids

Thermal Integrated Pumped Thermal Energy Storage (TI-PTES) is a promising technology for large-scale energy storage attributed to the advantages of geographical independence, high efficiency, low cost, and easy coupling with other systems. Little research has been dedicated to TI-PTES based on the organic flash cycle (OFC). This study established thermodynamic analysis of the TI-PTES based on the organic Rankine cycle (ORC) and OFC. The effects of system configurations and key parameters are explored. A multi-objective optimization is introduced to optimize the ORC-TI-PTES, and the P2P efficiency of 57.18 %, exergy efficiency of 37.47 %, and ESD of 4.4 kWh/m3 are achieved. The potential application of zeotropic mixture working fluids in the OFC-TI-PTES is investigated. The DOFC-TI-PTES with [R365mfc(60 wt%) + R1234ze(Z)] shows the best performance among the four OFC configurations. The achieved P2P efficiency and exergy efficiency are 46.66 % and 29.18 %, lower than the ORC-TI-PTES. However, the DOFC-TI-PTES provides an ESD of 11.487 kWh/m3, which is significantly higher than that of the ORC-TI-PTES. ORC-TI-PTES is suitable for energy storage applications that prioritize high thermal and exergy efficiencies, whereas OFC-TI-PTES is suitable for scenarios requiring high ESD.

Low-emissions hydrogen from MCH dehydrogenation: Integration with LNG regasification

Methylcyclohexane (MCH) is a promising organic hydride carrier for hydrogen transport and storage. Recovering hydrogen from MCH is an energy intensive process. An innovative idea of integrating this process with liquified natural gas (LNG) regasification is proposed in this study and demonstrated via modelling and simulation to substantially reduce external energy use. The synergistic benefits are twofold. In addition to providing a cold energy source for an effective high recovery cryogenic flash separation, the organic Rankine cycle based electrical power generation potential from LNG cold energy is fully exploited to reduce/eliminate external electricity demand for hydrogen compression to the high (end use) pressure. The results is a major reduction in carbon dioxide emissions. The proposed design for an integrated LNG-H2terminal can supply (1) 99.99 mol% pure hydrogen to a Combined Cycle Gas Turbine (CCGT) power plant and (2) commercial-grade natural gas to a gas-grid, both at the desired pressures and temperatures. Subsequently, rigorous simulation-based optimization was performed to minimize external energy inputs.A case study with 100 tph MCH and 100 tph LNG showed that integrating regasification with dehydrogenation produced 6.2 tph of hydrogen while gasifying LNG with a net power generation of 310 kW and a hydrogen recovery cost of 0.282 $/kg H2. Up to 7.3 tonnes of hydrogen can be produced per 100 tonnes of LNG without the use of external power. On the other hand, using external power, up to 11.3 tonnes of hydrogen can be produced per 100 tonnes of LNG without any external refrigeration. Overall, the superstructure proposed in this manuscript provides a generic initial approach for future MCH hydrogen supply chain projects, when considering integrations with LNG regasification plants.

Development of a solar-ocean based integrated plant with a new hydrogen generation system

Considering the global urgency to decrease carbon emissions and shift to sustainable energy sources, combining solar and other renewables with hydrogen generation appears to offer an appealing answer. The combination of solar and ocean energies with hydrogen production, therefore, offers a great potential to improve energy efficiency and create a feasible route towards zero-emission energy systems. A new hybrid photoelectrochemical (PEC)-conventional electrolysis system was designed and incorporated into the proposed multigeneration system. The hybridized reactor combines the benefits of PEC and conventional electrolysis by using a developed bipolar anode to produce hydrogen continuously, even when there is no solar radiation. The main aim of this research is to investigate the integrated power process that utilizes solar power for several uses, such as generating electricity, producing freshwater, and synthesizing hydrogen. The proposed research involves integrating several components, including a solar through collector system, a combination of power cycles (steam and organic Rankine cycles), a multi-effect desalination (MED) unit, a new hybrid electrolyzer system, a wave energy system, and a hydrogen storage and refuelling station. The main outputs include 2.05 kg/s freshwater production, 0.125 kg/s hydrogen production, 16,284.24 kW net work rate, and 95,068 kW solar heat input. The highest exergy destruction rates were found in the solar collector (56,194.8 kW) and turbines T1 and T2 (6019.9 and 4627.6 kW). The overall energy and exergy efficiencies of the proposed system are obtained to be 15.83 % and 16.61 %, respectively.