Energetic and exergetic assessments of a novel solar power tower based multigeneration system with hydrogen production and liquefaction

In this article, a thermodynamic investigation of solar power tower assisted multigeneration system with hydrogen production and liquefaction is presented for more environmentally-benign multigenerational outputs. The proposed multigeneration system is consisted of mainly eight sub-systems, such as a solar power tower, a high temperature solid oxide steam electrolyzer, a steam Rankine cycle with two turbines, a hydrogen generation and liquefaction cycle, a quadruple effect absorption cooling process, a drying process, a membrane distillation unit and a domestic hot water tank to supply hydrogen, electrical power, heating, cooling, dry products, fresh and hot water generation for a community. The energetic and exergetic efficiencies for the performance of the present multigeneration system are found as 65.17% and 62.35%, respectively. Also, numerous operating conditions and parameters of the systems and their effects on the respective energy and exergy efficiencies are investigated, evaluated and discussed in this study. A parametric study is carried out to analyze the impact of various system design indicators on the sub-systems, exergy destruction rates and exergetic efficiencies and COPs. In addition, the impacts of varying the ambient temperature and solar radiation intensity on the irreversibility and exergetic performance for the present multigeneration system and its components are investigated and evaluated comparatively. According to the modeling results, the solar irradiation intensity is found to be the most influential parameter among other conditions and factors on system performance.     

Energy and exergy performance assessment of a novel solar-based integrated system with hydrogen production

In this study, a new solar power assisted multigeneration system designed and thermodynamically analyzed. In this system, it is designed to perform heating, cooling, drying, hydrogen and power generation with a single energy input. The proposed study consists of seven sub-parts which are namely parabolic dish solar collector, Rankine cycle, organic Rankine cycle, PEM-electrolyzer, double effect absorption cooling, dryer and heat pump. The effects of varying reference temperature, solar irradiation, input and output pressure of high-pressure turbine and pinch point temperature heat recovery steam generator are investigated on the energetic and exergetic performance of integration system. Thermodynamic analysis result outputs show that the energy and exergy performance of overall study are computed as 48.19% and 43.57%, respectively. Moreover, the highest rate of irreversibility has the parabolic dish collector with 24,750 kW, while the lowest rate of irreversibility is calculated as 5745 kW in dryer. In addition, the main contribution of this study is that the solar-assisted multi-generation systems have good potential in terms of energy and exergy efficiency.     

Thermodynamic analyses of a solar-based combined cycle integrated with electrolyzer for hydrogen production

In the current study, a combined steam and gas turbine system integrated with solar system is studied thermodynamically. In addition, an electrolyzer is added to the integrated system for hydrogen production which makes the current system more environmental friendly and sustainable. This system is then evaluated by employing thermodynamic analysis to obtain both energetic and exergetic efficiencies. The parametric studies are also conducted to investigate the effects of varying operating conditions and state properties on both energy and exergy efficiencies. The present results show that while gas turbine can generate 312 MW directly, 151.72 MW power is generated by steam turbine using solar collectors and exhausted gases recovered from the gas turbine. Furthermore, by adding electrolyzer to the integrated system, a total of 131.3 g/s (472.68 kg/h) hydrogen is generated by using excess electricity which leads to more sustainability system.     

Thermodynamic performance assessment of ocean thermal energy conversion based hydrogen production and liquefaction process

In the proposed study, the thermodynamic performance assessment of ocean thermal energy conversion (OTEC) based hydrogen generation and liquefaction system are evaluated. In this context, the energetic and exergetic analyses of integrated system are conducted for multigeneration. This integrated process is consisted of the heat exchangers, turbine, condenser, pumps, solar collector system, hot storage tank, cold storage tank and proton exchange membrane (PEM) electrolyzer. In addition to that, the impacts of different design indicators and reference ambient parameters on the exergetic performance and exergy destruction rate of OTEC based hydrogen production system are analyzed. The energetic and exergetic efficiencies of integrated system are founded as 43.49% and 36.49%, respectively.     

Thermodynamic performance analysis and environmental impact assessment of an integrated system for hydrogen and ammonia generation

A novel multigeneration plant that's using natural gas for power, hydrogen, ammonia, and hot water generation, is planned and analyzed, in the current paper. The suggested combined plant integrated with four sub-systems, which are the Brayton cycle, reheat Rankine cycle, the high-temperature steam electrolyzer for hydrogen production, and ammonia synthesis processes. Also, thermodynamic analysis and environmental impact assessment are conducted for the designed plant and sub-systems. Moreover, the sustainability index analysis of this proposed study is conducted. The effects of some important indicators on the performance and on the environmental impact of the modeled system and sub-processes are also studied. According to analyses results, it is noted that the energetic and exergetic efficiencies of the suggested system are 51.83% and 70.27%, respectively, and also the total CO₂ emission rate is 11.4 kg/kWh for the integrated plant. Furthermore, the total irreversibility rate is computed as 40007.68 kW, and furthermore, the combustion chamber has a maximum irreversibility rate with 20,033 kW, among the proposed plant components.     

Investigation of a new integrated system for multiple outputs with hydrogen and methanol

In this study, an integrated multigeneration system that can produce hydrogen, electricity, heat, and methanol simultaneously is thermodynamically investigated. This integrated multigeneration system consists of three subsystems, namely: (i) electrolyzer, (ii) thermal power plant; and (iii) methanol production reactor. Energy and exergy analyses of all system components, as well as the sustainability analysis of the whole system, is performed thoroughly. The integrated system's thermodynamic performance is thoroughly investigated by changing some critical operational and environmental parameters in parametric studies. Based on the results of this study, recommendations for better energetic, exergetic, and environmental performance are presented for better sustainability. The results of this study show that the integrated multigeneration system is capable of producing hydrogen, heat, electricity, and methanol with overall energetic and exergetic efficiencies about 68% and 47%, respectively.     

Design and analysis of a new solar hydrogen plant for power,methane, ammonia and urea generation

In this paper, a solar power-based combined plant for power, hydrogen, methane, ammonia and urea production is proposed. A parabolic trough collector is utilized for the system prime mover. Moreover, steam Rankine cycle, organic Rankine cycle, hydrogen production and compression subsystem, ammonia, methane and urea production units, single-effect absorption cooling unit, and freshwater production plant are integrated together to develop the present system for better system performance and cost-effectiveness and reduced environmental impact. In order to analyze and evaluate the proposed multigeneration plant, thermodynamic, parametric and economic studies are performed. According to the assessment results, it is found that energetic and exergetic efficiencies of the present multigeneration plant are 66.12% and 61.56%, respectively. The comparisons of the subsystem and overall plant efficiencies show that the highest energetic and energetic efficiencies belong to freshwater production plant by 79.24% and 75.62%, respectively. In addition, the present parametric analysis indicates that an increase in the reference temperature, solar radiation intensity and working pressure of the solar process has a positive effect on the plant's performance. The cost analysis reveals that as the solar radiation intensity and the working pressure of the solar process increase, the hydrogen generation cost decreases. Furthermore, the hydrogen generation cost is achieved to be 1.94 $/kgH₂ at 650 W/m² of the solar radiation intensity, with other parameters remaining constant.     

A novel renewable energy-based integrated system with thermoelectric generators for a net-zero energy house

A renewable energy based integrated system is developed to meet the total energy demands of a house located off-grid, and a thermodynamic analysis through energy and exergy methodologies is conducted for analysis, evaluation, and performance assessment. The present novel multigeneration system is mainly driven through the animal residues produced at the farm house. The proposed novel system is composed of nine main units namely, a biomass combustor, photovoltaic (PV) panels, parabolic solar trough collectors, thermoelectric generators, organic Rankine cycle, electrolyzer, homogeneous charged compression ignition (HCCI) engine, absorption chiller, and reverse osmosis (RO) unit. Biomass combustor runs an organic Rankine turbine for additional power during peak loads. The exhaust of gas turbine generates cooling to meet the cooling demand of the residential area of the farm house. PV panels are incorporated to generate hydrogen through electrolyzer. A HCCI engine generates power to compensate peak load as well as charging the farming vehicles of the farm house. The RO unit with energy recovery Pelton turbine produces fresh water for farming and residential use. The advanced integration of subsystems, thermoelectric generators and efficient utilization of waste, improves significant amount of energetic and exergetic efficiencies of overall multigenerational system. The energy and exergy efficiencies are enhanced in the order of 4.8% and 6.3%, respectively, after incorporating innovative cooling system to the PV modules. The overall energy and exergy efficiencies of the proposed multigeneration system with and without thermoelectric are found to be 67.6% and 57.1%, and 68.9% and 58.4%, respectively.     

A novel combined biomass and solar energy conversion-based multigeneration system with hydrogen and ammonia generation

In the present study, an innovative multigeneration plant for hydrogen and ammonia generation based on solar and biomass power sources is suggested. The proposed integrated system is designed with the integration of different subsystems that enable different useful products such as power and hydrogen to be obtained. Performance evaluation of designed plant is carried out using different techniques. The energetic and exergetic analyses are applied to investigate and model the integrated plant. The plant consists of the parabolic dish collector, biomass gasifier, PEM electrolyzer and hydrogen compressor unit, ammonia reactor and ammonia storage tank unit, Rankine cycle, ORC cycle, ejector cooling unit, dryer unit and hot water production unit. The biomass gasifier unit is operated to convert biomass to synthesis gaseous, and the concentrating solar power plant is utilized to harness the free solar power. In the proposed plant, the electricity is obtained by using the gas, Rankine and ORC turbines. Additionally, the plant generates compressed hydrogen, ammonia, cooling effect and hot water with a PEM electrolyzer and compressed plant, ammonia reactor, ejector process and clean-water heater, respectively. The plant total electrical energy output is calculated as 20,125 kW, while the plant energetic and exergetic effectiveness are 58.76% and 55.64%. Furthermore, the hydrogen and ammonia generation are found to be 0.0855 kg/s and 0.3336 kg/s.     

A thermal performance evaluation of a new integrated gas turbine-based multigeneration plant with hydrogen and ammonia production

In this study, a new combined system driving a gas turbine cycle has been proposed for seven useful outputs of power, hydrogen, ammonia, heating-cooling, drying and hot water. The proposed integrated plant mainly consists of the gas turbine cycle, Rankine cycle, two organic Rankine cycles, ejector-based cooling, hydrogen production and liquefaction, ammonia production and storage, drying and hot water generation sub-systems. In order to demonstrate that the designed system is an efficient and environmentally plant, the performance analysis was performed by using a software package. Before performing the performance assessment of the plant, the mathematical model of the integrated plant is prepared in accordance with thermodynamic equations. Basic equilibrium equations are used for the thermodynamic equations used. Obtaining multiple useful outputs from the system also have the positive effect on the system effectiveness. The energetic effectiveness of integrated plant for multigeneration with hydrogen and ammonia production is computed to be 62.18% and exergetic efficiency is 58.37%. In addition, the energetic and exergetic effectiveness of hydrogen production and liquefaction process are 57.92% and 54.23%, respectively.     

Thermodynamic performance analysis of a copper–chlorine thermochemical cycle and biomass based combined plant for multigeneration

The primary objective of this work is to investigate a comprehensive thermodynamic assessment of the biomass-assisted multigeneration plant for electrical energy, hydrogen, heating-cooling, drying, and hot water production. The suggested multigeneration plant includes the biomass gasification process, Brayton cycle, Kalina cycle, organic Rankine cycle, and cascade refrigeration plant, which is to produce heating and cooling loads, drying system, hydrogen generation with copper–chlorine thermochemical process, and hydrogen liquefaction process. Based on the thermodynamic laws, the total irreversibility rate and performance assessment of the examined study is conducted. Moreover, the impact of various factors such as reference temperature, biomass gasifier temperature, and mass flow rate of biofuel, on the effectiveness and useful outputs of planned plant are examined. The outcomes of the proposed study show that 18 626, 3948 and 1037 kW electrical energy are generated by using the Brayton, Kalina, and organic Rankine cycle. Furthermore, the total cooling and heating capacities and hydrogen generation rates are 2392, 2864 kW and 0.068 kg s⁻¹. Finally, energetic and exergetic effectiveness of the examined model are calculated as 56.71% and 53.59%.     

Performance assessment of an integrated PV/T and triple effect cooling system for hydrogen and cooling production

In this paper we study an integrated PV/T absorption system for cooling and hydrogen production based on U.A.E weather data. Effect of average solar radiation for different months, operating time of the electrolyzer, air inlet temperature and area of the PV module on power and rate of heat production, energy and exergy efficiencies, hydrogen production and energetic and exergetic COPs are studied. It is found that the overall energy and exergy efficiency varies greatly from month to month because of the variation of solar radiation and the time for which it is available. The highest energy and exergy efficiencies are obtained for the month of March and their value is 15.6% and 7.9%, respectively. However, the hydrogen production is maximum for the month of August and its value is 9.7 kg because in august, the solar radiation is high and is available for almost 13 h daily. The maximum energetic and exergetic COPs are calculated to be 2.28 and 2.145, respectively and they are obtained in the month of June when solar radiation is high for the specified cooling load of 15 kW.     

Thermodynamic analysis and assessment of a novel integrated geothermal energy-based system for hydrogen production and storage

In this paper, thermodynamic analysis and assessment of a novel geothermal energy based integrated system for power, hydrogen, oxygen, cooling, heat and hot water production are performed. This integrated process consists of (a) geothermal subsystem, (b) Kalina cycle, (c) single effect absorption cooling subsystem and (d) hydrogen generation and storage subsystems. The impacts of some design parameters, such as absorption chiller evaporator temperature, geothermal source temperature, turbine input pressure and pinch point temperature on the integrated system performance are investigated to achieve more efficient and more effective. Also, the impacts of reference temperature and geothermal water temperature on the integrated system performance are studied in detail. The energetic and exergetic efficiencies of the integrated system are then calculated as 42.59% and 48.24%, respectively.     

Geothermal and solar energy–based multigeneration system for a district

In this study, parabolic trough collector with an integrated source of geothermal water is used with regenerative Rankine cycle with an open feedwater heater, an electrolyzer, and an absorption cooling system. The absorption fluids used in the solar collectors were Al₂O₃‐ and Fe₂O₃‐based nanofluids. Detailed energetic and exergetic analyses are done for the whole system including all the components. A comparative analysis of both the used working fluids is done and plotted against their different results. The parameters that are varied to change the output of the system are ambient temperature, solar irradiance, the percentage of nanofluids, the mass flow rate of the geothermal well, the temperature gradient of the geothermal well that had an effect on the net power produced, and the outlet temperature of the solar collector overall energetic and exergetic efficiencies. Other useful outputs by this domestic integrated multigeneration system are the heating of domestic water, space heating (maintaining the temperature at 40°C‐50°C), and desalination of seawater (flash distillation). The hydrogen production rate for both the fluids diverges with each other, both producing average from 0.00490 to 0.0567 g/s.     

Energetic and exergetic performance evaluations of a geothermal power plant based integrated system for hydrogen production

In this paper, we propose an integrated system aiming for hydrogen production with by-products using geothermal power as a renewable energy source. In analyzing the system, an extensive thermodynamic model of the proposed system is developed and presented accordingly. In addition, the energetic and exergetic efficiencies and exergy destruction rates for the whole system and its parts are defined. Due to the significance of some parameters, the impacts of varying working conditions are also investigated. The results of the energetic and exergetic analyses of the integrated system show that the energy and exergy efficiencies are 39.46% and 44.27%, respectively. Furthermore, the system performance increases with the increasing geothermal source temperature and reference temperature while it decreases with the increasing pinch point temperature and turbine inlet pressure.     

Parametric analysis of a solar energy based multigeneration plant with SOFC for hydrogen generation

Renewable energy-based hydrogen production plants can offer potential solutions to both ensuring sustainability in energy generation systems and designing environmentally friendly systems. In this combined work, a novel solar energy supported plant is proposed that can generate hydrogen, electricity, heating, cooling and hot water. With the suggested integrated plant, the potential of solar energy usage is increased for energy generation systems. The modeled integrated system generally consists of the solar power cycle, solid oxide fuel cell plant, gas turbine process, supercritical power plant, organic Rankine cycle, cooling cycle, hydrogen production and liquefaction plant, and hot water production sub-system. To conduct a comprehensive thermodynamic performance analysis of the suggested plant, the combined plant is modeled according to thermodynamic equilibrium equations. A performance assessment is also conducted to evaluate the impact of several plant indicators on performance characteristics of integrated system and its sub-parts. Hydrogen production rate in the suggested plant according to the performance analysis performed is realized as 0.0642 kg/s. While maximum exergy destruction rate is seen in the solar power plant with 8279 kW, the cooling plant has the lowest exergy destruction rate as 1098 kW. Also, the highest power generation is obtained from gas turbine cycle with 7053 kW. In addition, energetic and exergetic efficiencies of solar power based combined cycle are found as 56.48% and 54.06%, respectively.     

Development and thermodynamic assessment of a novel solar and biomass energy based integrated plant for liquid hydrogen production

In this paper, a combined power plant based on the dish collector and biomass gasifier has been designed to produce liquefied hydrogen and beneficial outputs. The proposed solar and biomass energy based combined power system consists of seven different subplants, such as solar power process, biomass gasification plant, gas turbine cycle, hydrogen generation and liquefaction system, Kalina cycle, organic Rankine cycle, and single-effect absorption plant with ejector. The main useful outputs from the combined plant include power, liquid hydrogen, heating-cooling, and hot water. To evaluate the efficiency of integrated solar energy plant, energetic and exergetic effectiveness of both the whole plant and the sub-plants are performed. For this solar and biomass gasification based combined plant, the generation rates for useful outputs covering the total electricity, cooling, heating and hydrogen, and hot water are obtained as nearly 3.9 MW, 6584 kW, 4206 kW, and 0.087 kg/s in the base design situations. The energy and exergy performances of the whole system are calculated as 51.93% and 47.14%. Also, the functional exergy of the whole system is calculated as 9.18% for the base working parameters. In addition to calculating thermodynamic efficiencies, a parametric plant is conducted to examine the impacts of reference temperature, solar radiation intensity, gasifier temperature, combustion temperature, compression ratio of Brayton cycle, inlet temperature of separator 2, organic Rankine cycle turbine and pump input temperature, and gas turbine input temperature on the combined plant performance.     

Thermodynamic analysis of a tri-generation system based on micro-gas turbine with a steam ejector refrigeration system

In the present work, performance of new configuration of Micro-gas turbine cogeneration and tri-generation systems, with a steam ejector refrigeration system and Heat recovery Steam Generator (HRSG) are studied. A micro-gas turbine cycle produces 200 KW power and exhaust gases of this micro-gas turbine are recovered in an HRSG. The main part of saturated steam in HRSG is used through a steam ejector refrigeration system to produce cooling in summer. In winter, this part of saturated steam is used to produce heating. In the first part of this paper, performance evaluation of this system with respect to Energy Utilization Factor (EUF), Fuel Energy Saving Ratio (FESR), thermal efficiency, pinch point temperature difference, net power to evaporator cooling load and power to heat ratio is carried out. It has been shown that by using the present cogeneration system, one can save fuel consumption from about 23% in summer up to 33% in winter in comparison with separate generation of heating, cooling and electricity.     

Exergy based performance analysis of a solid oxide fuel cell and steam injected gas turbine hybrid power system

This paper presents exergy analysis of a hybrid solid oxide fuel cell and gas turbine (SOFC/GT) system in comparison with retrofitted system with steam injection. It is proposed to use hot gas turbine exhaust gases heat in a heat recovery steam generator to produce steam and inject it into gas turbine. Based on a steady-state model of the processes, exergy flow rates are calculated for all components and a detailed exergy analysis is performed. The components with the highest proportion of irreversibility in the hybrid systems are identified and compared. It is shown that steam injection decreases the wasted exergy from the system exhaust and boosts the exergetic efficiency by 12.11%. Also, 17.87% and 12.31% increase in exergy output and the thermal efficiency, respectively, is demonstrated. A parametric study is also performed for different values of compression pressure ratio, current density and pinch point temperature difference.     

Thermodynamic studies of a novel heat pipe evacuated tube solar collectors based integrated process for hydrogen production

In this study, the detailed thermodynamic assessment of an integrated process based on heat pipe evacuated tube solar collectors for hydrogen production is provided for more efficiently process designs. An integrated process consists of the solar heat pipe collector, photovoltaic panels, PEM electrolyzer and Linde-Hampson hydrogen liquefaction process are considered and analyzed thermodynamically for hydrogen production and liquefaction aims. The energetic and exergetic efficiencies of this integrated process are calculated as 0.2297 and 0.1955, respectively. Based on the parametric study, the effectiveness of the solar energy based integrated process is also highly dependent on the solar flux and ambient conditions.