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A cogeneration of power and hydrogen plant driven by clean solar energy is developed, analyzed and optimized in this paper. For hydrogen production in the suggested plant, a thermochemical cycle with Vanadium–Chlorine (VCl) working pair is integrated with parabolic trough collectors and an auxiliary heater to provide the required temperature level. For power generation, however, an organic Rankine cycle is applied to generate electricity from extra heat which is not utilized in VCl thermochemical cycle. For performance improvement of developed cogeneration framework, nanoparticles are applied for enhancing thermal behavior of collector field. A comprehensive analysis is conducted to determine system performance enhancement with nanufluid as compared to basefluid case in thermal loop of collectors. Thermodynamic investigations paying more attention on exergy evaluations are carried out along with economic considerations to assess system performance. Furthermore, to address the proposed plant's environmental impacts, the overall plant's performance and carbon dioxide emission reduction are estimated. Parametric appraisal is implemented to specify operating factor impacts on power and hydrogen production and unit cost of product. Also, multi-objective optimization is performed based on cost and efficiency indices. It is found that, addition of nanoparticles to basefluid can enhance system performance roughly by 3 − 5 %. The nanofluid based framework attains efficiency of 40.16% and unit product cost of 39.93 $/GJ under optimum conditions. Finally, based on the findings of the environmental impact analysis, the designed system in cogeneration mode was able to mitigate CO 2 emissions by 1173 kg/h. • Parabolic trough solar collectors are coupled with thermochemical hydrogen production. • Nanoparticles are used to enhance thermal performance of solar loop. • Improvement of 3–5% is found with nanoparticles' utilization on overall system. [ABSTRACT FROM AUTHOR]

One of the reasons why renewable energies are so attractive compared to fossil fuels is their low environmental impact. In addition, geothermal power plants contribute tremendously to sustainable energy generation for cities despite their lower energy efficiency than fossil fuel plants. The multi-heat recovery will eliminate the applicability defect mentioned. Therefore, this paper studies a novel tri-generation schema with the maximum use of heat loss through a multi-heat recovery technique in two principal processes, namely waste heat-to-power and power-to-H 2 and -purified water. A double-flash binary cycle, Rankine cycle, electrolyzer unit, and reverse osmosis desalination system all play a part in the creation of this system. The technical feasibility of the system is scrutinized based on energy-exergy, environmental, sustainability, and exergoeconomic metrics and bi-objective optimization. Generally, 1st separator pressure made the strongest effect on the measured variables among decision variables. The increase in this parameter led to an upward-and-downward behavior of the net electricity and exergetic efficiency; while the cost of products experienced a converse trend. Also, the produced H 2 and purified water together with the tri-generation gain output ratio augmented. Changes were not observed in net electricity and purified water with the change in 2nd separator pressure, but the H 2 production rate changed significantly. Through bi-objective optimization, net electricity, purified water production rate, and total investment cost rate also significantly increase. Based on the optimum design mode, the CO 2 emission rate and the sustainability index are higher than under the base case design. • Using multi-heat recovery technique in two principal processes, namely, waste heat-to-power and power-to-H2 and -purified water. • Evaluation of system indices based on energy-exergy and exergoeconomic metrics and bi-objective optimization. • Exergetic efficiency, TGOR, and the cost of products improved by 5.19%, 109.52%, and 8.54%, separately, thanks to bi-objective optimization. [ABSTRACT FROM AUTHOR]

Due to the fact that biomass fuel is capable of powering multi-generation systems, has a high-efficiency performance, and produces fewer harmful gases, biomass fuel can prove to be a valuable heat source. In this regard, this study introduces a new biomass-fueled power and hydrogen generation scheme. There are three subsystems involved in the study: a biomass-based gas turbine cycle, a steam flash cycle, and an electrolyzer unit. To begin, a parametric analysis is performed on the system from the perspectives of thermodynamics, thermoeconomic, and the environment. As a next step, four effective variables are evaluated for single-objective and bi-objective optimizations in order to determine the optimal working conditions. The results of bi-objective optimization indicate 48.78% and 41.40% energy and exergy efficiencies for the presented system, separately, with 8093 kW output power, 86.1 kg/day hydrogen production, 8684 t/MWh CO 2 emission, and 27.9 $/MWh Levelized Cost of Product. Compared to the base condition, hydrogen production grows 29.78%, but output power drops by 1.14%. Furthermore, hydrogen Production Optimum Design accounts for the maximum amount of hydrogen production in optimal conditions, producing 94.73 kg/day. The gasifier destroys the most exergy under base and optimum conditions. • Proposal of a novel power/hydrogen cogeneration system including a gas turbine cycle. • The utilization of a steam flash cycle integrated with an electrolyzer to generate more power. • Evaluating system performance using thermodynamic, thermoeconomic, and environmental metrics. • The highest cost is related to the gas turbine in the optimized condition based on output power. • The proposed system performs better than the existing related ones in the literature. [ABSTRACT FROM AUTHOR]

Biomass can be used as fuel of fuel cells by conducting thermochemical process such as biomass gasification. In this study, the required fuel of a solid oxide fuel cell was supplied through pine gasification in a gasifier reactor. The purpose of this study was provided an appropriate configuration to a co-generation system produced heat and power and the state with maximum heat and power production and minimum carbon dioxide emission was obtained. The outputs were power, heat, and CO 2 emission investigated with respect to steam to biomass ratio of gasification and current density and fuel utilization factor of solid oxide fuel cell. The results indicated that fuel utilization factor contributed the most on power and hot water with shares of 73.64% and 47.27%, respectively. However, current density had the highest influence on carbon dioxide emission with a share of 83.41%. Parametric analysis illustrated that increasing fuel utilization factor remarkably enhanced the power production and mitigated hot water production. A considerable reduction was observed in carbon dioxide emission by increasing current density. Single-objective and multi-objective optimizations revealed that steam to biomass ratio of 2, 4600 A/m2 of current density, 0.77 of utilization factor are the optimum states. Power production of 196.8 kW, hot water production of 1203 g/s, and carbon dioxide emission of 1261 kg/MW.h were the outputs of the optimum state. • Production of clean heat and power by SOFC and pine steam gasification. • Identifying effective parameters on system performance using analysis of variance. • Optimization of the system through response surface methodology. • Considering power, hot water, and CO 2 emission as optimization's objectives. [ABSTRACT FROM AUTHOR]

World energy markets are gradually shifting in favor of wind-based power plants. A decrease in global warming can be attributed to the reduction of dependence on fossil fuels as a result of wind energy. In this regard, utilizing the waste heat from the generator of a wind turbine has recently been considered and only a few studies have been done about it. This shortage has made clear the need for further studies. In the present research, a novel poly-generation system is introduced based on the waste heat recovery of a wind turbine to fill this research gap because the waste energy of a wind turbine has not been utilized for the poly-generation purpose. A novel power-cooling production absorption cycle and a domestic hot water heat exchanger are utilized for this purpose. Also, the produced power in the absorption cycle is sent to a reverse osmosis desalination unit for freshwater production. The considered system is comprehensively studied from energy, exergy, environmental, and exergo-economic standpoints. In the average wind speed of 10 m/s, the exergy efficiency, unit cost of products, reduction in CO 2 emission rate, and payback period are seen to be 36.76%, 20.25 $/GJ, 2452801 kg/year, and 2.301 years, which shows its performance is better than the previous studies based on the waste heat recovery of a single wind turbine. • Waste heat recovery of a wind turbine for poly-generation purpose. • Energy and exergo-economic analyses are done through parametric study. • Wind turbine is the major contributor in exergy destruction and cost rates. • This waste heat recovery produces 73.25 kW heating, 45.86 kW cooling, and 0.274 kg/s of freshwater. [ABSTRACT FROM AUTHOR]