• Energy Research
• 2021-2025close
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This paper presents a new framework for optimal planning of electrical, heating, and cooling distributed energy resources and networks considering smart buildings' contribution scenarios in normal and external shock conditions. The main contribution of this paper is that the impacts of smart buildings' commitment scenarios on the planning of electrical, heating, and cooling systems are explored. The proposed iterative four-stage optimization framework is another contribution of this paper, which utilizes a self-healing performance index to assess the level of resiliency of the multi-carrier energy system. In the first stage, the optimal decision variables of planning are determined. Then, in the second stage, the smart buildings and parking lots contribution scenarios are explored. In the third stage, the optimal hourly scheduling of the energy system for the normal condition is performed considering the self-healing performance index. Finally, in the fourth stage, the optimization process determines the optimal scheduling of system resources and the switching status of electrical switches, heating, and cooling pipelines’ control valves. The proposed method was successfully assessed for the 123-bus IEEE test system. The proposed framework reduced the expected values of aggregated system costs and energy not supplied costs by about 49.92% and 93.64%, respectively, concerning the custom planning exercise. ; © 2023 The Author(s). Published by Elsevier Ltd. This is an open access article under the CC BY license (http://creativecommons.org/licenses/by/4.0/). ; fi=vertaisarvioitu|en=peerReviewed|

Abstract A novel integrated energy system based on a geothermal heat source and a liquefied natural gas heat sink is proposed in this study for providing heating, cooling, electricity power, and drinking water simultaneously. The arrangement is a cascade incorporating a flash-binary geothermal system, a regenerative organic Rankine cycle, a simple organic Rankine cycle, a vapor compression refrigeration cycle, a regasification unit, and a reverse osmosis desalination system. Energy, exergy, and exergoeconomic methods are employed to analyze the suggested system. A parametric study based on decision variables is carried out to better assess the system performance. Four different multi-objective optimization problems are also carried out. At the most excellent trade-off solution specified by the TOPSIS method, the system attains 29.15% exergy efficiency and 1.512 $/GJ total product cost per exergy unit. The main output products are consequently calculated to be 101.07 kg/s cooling water, 570.44 kW net output power, and 81.57 kg/s potable water.

Abstract In the paper a novel approach to thermochemical utilization of low rank coal, flotation concentrates and municipal refuse derived fuels was presented. The economic attractiveness of low rank coals and flotation concentrates is limited and that is why they are commonly stored at excavation heaps causing additional costs and the risk of endogenous fires occurrence. One of the crucial parameters determining the attractiveness and usability of a fuel in the gasification process is its reactivity. In the study several low rank coals, flotation concentrates and municipal refuse derived fuels were tested in terms of their reactivity in the process of steam gasification. The reactivity of low rank coal and flotation concentrates at 50% of carbon conversion, R50, varied between 1.46·10−4 and 2.39·10−4 s−1, whereas the maximum reactivity, Rmax, from 3.28·10−4 to 4.62·10−4 s−1. Advanced mathematical models were developed to investigate the similarities and dissimilarities between the studied fuels as well as the relationships between the physical and chemical parameters and the reactivities of fuel chars in steam gasification. On this basis, a low rank coal was selected and blended with 20%w/w of municipal refuse derived fuel in co-gasification experiments. The aim of the research was to utilize the low rank coal characterized by the lowest reactivities (R50 and Rmax of 1.46·10−4 and 3.28·10−4 s−1, respectively) in steam co-gasification to hydrogen-rich gas with an alternative fuel in a fixed bed reactor at the temperature of 800 °C. The selected low rank coal was blended with 20%w/w of municipal refuse derived and the resulting fuel yielded the average concentration of hydrogen in the produced gas of 58.99%vol.

Renewable resources and energy storage systems integrated into microgrids are crucial in attaining sustainable energy consumption and energy cost savings. This study conducts an in-depth analysis of diverse storage systems within multi-energy microgrids, including natural gas and electricity subsystems, with a comprehensive focus on techno-economic considerations. To achieve this objective, a methodology is developed, comprising an optimization model that facilitates the determination of optimal storage system locations within microgrids. The model considers various factors, such as operating and emission costs of both gas and electricity subsystems, and incorporates a sensitivity analysis to calculate the investment and maintenance costs associated with the storage systems. Due to the incorporation of voltage and current relations in the electricity subsystem as well as gas pressure and flow considerations in the natural gas subsystem, the developed model is classified as a mixed-integer nonlinear programming model. To address the inherent complexity in solving, a decomposition approach based on Outer Approximation/Equality Relaxation/Augmented Penalty is developed. This study offers scientific insights into the costs of energy storage systems, potential operational cost savings, and technical considerations of microgrid operation. The results of the developed decomposition approach demonstrate significant advantages, including reduced solving time and a decreased number of iterations.

Abstract In this paper, to improve the performance of the thermodynamic system and reduce greenhouse gas emissions and fuel utilization, a novel power generation system based on syngas-fueled solid oxide fuel cell, gas turbine, organic flash cycle, and a thermoelectric generator was devised. The performance of the proposed system was analyzed through energy, exergy, exergoeconomic, economic, and environmental viewpoints. Finally, the multi-objective particle swarm optimization algorithm and TOPSIS and LINMAP decision-making methods were employed to obtain the optimum performance. According to the obtained results at the base operation condition, the main performance metrics were FX, FX, FX, FX, FX. For fuel cost of 3 $/GJ and electricity cost of FX, the payback time was around FXyears with a total profit of FX at the end of the economic lifetime. The parametric study revealed that the SOFC with anode and cathode gas recycling exhibits a higher exergy efficiency and lower Levelized total emissions. For the energy-cost optimization scenario, the optimum energy efficiency selected by LINMAP methods was FX, and the minimum total specific cost selected by TOPSIS method was FX. For the exergy-cost optimization scenario, the optimum exergy efficiency selected by TOPSIS was FX.

Abstract Alternative methods for clean production of hydrogen have been proposed recently. Some of these methods utilize water instead of hydrocarbons as the hydrogen source. The copper-chlorine (Cu–Cl) thermochemical cycle is one of the most promising methods that attracted the attention of numerous researchers and organizations in recent years. In this paper, the design and integration of a standalone solar power tower (SPT) system with LiNaK high-temperature carbonate molten salt with a four-step Cu–Cl cycle is investigated. The integrated system does not rely on external or auxiliary energy sources such as grid electricity or natural gas. The proposed system is investigated in terms of thermodynamic and economic analyses, and the system performance and hydrogen production cost are determined. For the base case, the thermal efficiencies of the Cu–Cl cycle, supercritical steam Rankine cycle, and overall system are 40.4%, 45.74%, and 28.77%, respectively. The hydrogen capacity of the system is 1530.4 kg/h, and the total capital investment is 811.04 million dollars. The levelized cost of hydrogen is estimated as $9.47/kg H2. Based on the multi-objective optimization results, the optimal system design has an overall thermal efficiency and levelized cost of hydrogen of 29.18% and $7.58/kg H2, respectively.

Abstract This investigation aims to present thermo-environmental and thermo-economic parametric studies for a new hybrid tri-generation energy system. In system, a regenerative gas turbine cycle (RGTC) is the runner system, while Kalina cycle (KC) and ejector refrigeration cycle (ERC) are considered as companion elements. The parametric study is done through validated computational program developed in EES software. Two new functions of levelized total annual emissions and costs ( LTAE and LTAC ), with two conventional indices of energetic and exergetic efficiencies ( η en and η ex ) are defined for system evaluation. Thermodynamics modeling revealed that almost 75 % of total exergy destruction is related to the RGTC. The outputs of parametric study prove that pressure ratio of compressor and pinch-point temperature of heat exchanger 2 are the most and least effective parameters, respectively. Also, for the bottoming cycles, changes in KC design parameters resulted in creation of peak points in all the evaluation criteria; but changes in the ERC design parameters resulted in uniform (ascending or descending) behavior in the evaluation criteria. The NSGA-II optimization procedure (using MATLAB software) results in η en , opt = 77.17 %, η ex , opt = 38.94 %, LTAE opt = 9.36 kg/kW.yr, and LTAC opt = 106.04 €/kW.yr. The payback period and net present value of the tri-generation system are found as 3.74 yr and 1184525.43 €.