A comprehensive approach for optimizing a biomass assisted geothermal power plant with freshwater production: Techno-economic and environmental evaluation
In the current research, a comprehensive thermodynamic study of an innovative biomass-geothermal power plant combined with a desalination system is presented and analyzed. The suggested system is a geothermal based cascaded steam/organic Rankine cycle benefiting from municipal solid waste combustion in order to enhance its performance. Besides, the exhaust gasses of municipal solid waste combustion are utilized as the primary energy source for driving a multi-effect desalination subsystem which converts the seawater into low salinity water. A comprehensive approach including energy and exergy analyses along with thermoeconomic evaluation is applied to investigate the viability of the plant. First of all, validation of the presented model has been tested by means of comparing the results with published data, through which a good agreement has achieved. The energy and exergy efficiencies can be …
Thermodynamic assessment and proposal of new configurations of an indirect water bath heater for a City Gate Station (a case study)
This paper deals with thermodynamic modeling and proposal new configurations of an indirect water bath heater used in a city gate station (CGS) to preheat the natural gas (NG). In the transmission pipeline of natural gas before reducing NG pressure, it is necessary preheating to prevent hydrate formation. In the traditional systems, an indirect water bath heater is used for this purpose. Thermodynamic modeling of the proposed systems has been done in EES software, and an effective analysis based on proposed new configurations is conducted. The results indicate that using exhaust combustion products to preheat the combustion air can increase the thermal efficiency of the system from 46.36% (for base case) to 73.84%. In addition, with the use of an ORC to utilize the exhaust waste thermal energy, the system efficiency of 55.27% with an electrical output of 79 kW can be achieved. A comparison between …
Improving the power generation efficiency with the use of LNG as cold source by thermoelectric generators for hydrogen production
In this study, thermodynamic simulation is developed to strengthening power generation efficiency utilizing liquefied natural gas (LNG) cold source by thermoelectric generators (TGs) for hydrogen production. Firstly, an organic Rankine cycle (ORC) is specified to use the cold energy of the LNG. Then, the cycle is simulated and the results are validated against the available research study data. Afterward, six locations are suggested to install the TGs and the effects of each of these locations on the cycle performance are evaluated. In addition, the economic evaluation of the selected system is done based on annual cash flow, levelized cost and payback time. The results indicate that the highest enhancement in thermal efficiency (TE) is related to Case “d” which the TG added between the seawater and LNG line. The results show that the TE will become 6.876% if the 80% output heat from the seawater enters the TG …
Ocean thermal energy conversion (OTEC) system boosted with solar energy and TEG based on exergy and exergo-environment analysis and multi-objective optimization
The primary goal of the current study is thermodynamic and environmental modeling and multi-objective optimization of a new hybrid energy system. The suggested ocean-based energy conversion system consists of an organic Rankine cycle (ORC), a solar flat plate collector, a proton exchange membrane (PEM) electrolyzer boosted with thermoelectric generator (TEG) module. Exergy and exergo-environmental as two powerful tools are employed to the precise assessment of the suggested system. To achieve the best performance of the integrated system, multi-criteria optimization with different objective functions is carried out. As the results of the parametric analysis indicate, defined objective goals have an appropriate conflict with changing decision variables, which is necessary in multi-criteria optimization. Four decision variables namely solar flat plate collector area (A p), solar radiation intensity (I), collector …
Design and comparative exergy and exergo-economic analyses of a novel integrated Kalina cycle improved with fuel cell and thermoelectric module
Combined cooling, heating, and power systems (CCHP) have attracted a lot of attention due to their distinctive advantages of high system and economic efficiencies in addition to less greenhouse gas emissions. The current study investigates the performance of a Kalina cycle-based CCHP system in which geothermal energy is utilized as the low temperature source of prime energy. A thermoelectric generator is used in the system for retrieving wasted heat and producing extra amount of electricity thereby leading to higher overall efficiency. Two types of fluids, i.e. geothermal water and mixture of water-ammonia, are employed for the steam cycle and Kalina cycle, respectively. A comparative performance analysis is carried out on three system configurations, namely; basic Kalina cycle system, Kalina cycle with a thermoelectric generator (TEG), and Kalina cycle integrated with TEG and a Proton Exchange Membrane …
Proposal of a new parabolic solar collector assisted power-refrigeration system integrated with thermoelectric generator using 3E analyses: Energy, exergy, and exergo-economic
In this study, a new parabolic solar collector integrated combined power and refrigeration system with the thermoelectric generator (CPR-PTSC with TEG) was proposed. The suggested system was evaluated through energy, exergy, and exergo-economic analyses, and the effect of the TEG on the power generation performance was investigated. The influences of significant parameters such as pressure ratio of supercritical Brayton cycle (BC), length of parabolic solar collector, turbine inlet pressure (TIP) of transcritical Rankine cycle (RC), compressor discharge pressure (CDP) of vapor compression refrigeration cycle (VCRC) were determined. According to the results, it was found that the integration of the thermoelectric units to the system improved the exergy performance of the system with an exergy destruction rate of 803.4 kW, where it was calculated as 821.38 kW for the system without TEG. The result of parametric …
On evaluation of magnetic field effect on the formation of nanoparticles clusters inside aqueous magnetite nanofluid: An experimental study and comprehensive modeling
This experimental study is conducted to explore the rheological behavior of magnetite-water ferrofluid in the attendance of an external magnetic field (MF). Tetramethylammonium hydroxide is used as surfactant to increase the stability of prepared ferrofluids. The impacts of MF strength (0–480 G) and volume concentration of nanoparticles (0.3–1.5%) on the outcomes are examined. It was found that as the shear rate increases, the viscosity decreases sharply and then tends to a fixed number and therefore, the magnetite-water has non-Newtonian pseudoplastic behavior. It was also found that the application of the MF both increases the viscosity and enhances the non-Newtonian behavior of the ferrofluid. Moreover, it was found that the rise of nanoparticle concentration (φ) leads to the increase of ferrofluid viscosity. Then, the artificial neural network is applied to develop a prediction model for the rheological behavior …
Tri-objective optimization of a hybrid solar-assisted power-refrigeration system working with supercritical carbon dioxide
The objective of current research is the optimization of a novel parabolic trough solar collector assisted power-refrigeration system. The innovative system utilizes CO2 as a working fluid, which is a natural medium and consisted of three sub-cycles: a Brayton cycle, a Rankine cycle, and a vapor compression refrigeration cycle. The main advantages of utilizing CO2 as working fluid are; available in large quantities, environmentally friendly properties such as negligible global warming potential and zero-ozone depletion, and excellent thermodynamic properties. The required heat energy demand of the system is supplied by solar energy using a PTSC. The thermodynamic performance of the system is examined in terms of energy and exergy analyses for a specified design configuration. An economic analysis of the suggested system is carried out for the optimization procedure. With the optimization results, the …
Development, evaluation, and multi-objective optimization of a multi-effect desalination unit integrated with a gas turbine plant
In this research study, a 40 MW gas turbine power plant, which is coupled with a multi-effect desalination system with thermal vapor compression, is investigated. The energy, exergy and exergoeconomic analyses of the integrated plant are presented. As the number of effects in a desalination system is a key parameter, the effect of number of effects on the system performance is investigated. The genetic algorithm-based multi-objective optimization is applied to determine the best decision variables. To achieve the best optimization states, different scenarios of multi objective optimization based on the total exergy destruction rate, unit electricity price, total cost rate, gain output ratio, distilled water cost, and total exergy efficiency are examined. Additionally, seven decision variables are compressor pressure ratio (r p), combustion temperature (T 3), compressor isentropic efficiency (η c), gas turbine isentropic efficiency …
Proposal of a novel integrated ocean thermal energy conversion system with flat plate solar collectors and thermoelectric generators: Energy, exergy and environmental analyses
The present study deals with energy, exergy and environmental evaluation of an integrated ocean thermal energy conversion (OTEC) system include a flat plate solar collector, an organic Rankine cycle, an electrolyzer system boosted with a thermoelectric generator (TEG) unit. To precise assessment of suggested systems and determine the effects of adding thermoelectric generator to the system a comparative analysis is carried out. Two considered systems are solar ocean thermal energy conversion (S-OTEC) and solar ocean thermal energy conversion with thermoelectric (S-OTEC/TEG). A thermodynamic model is formed using Engineering Equation Solver (EES) to solve the set of linear equations governing on the component of the system. The result of exergy analyses shows that adding thermoelectric module to the S-OTEC results in exergy efficiency increment by 6.27%. Also adding thermoelectric unit to the …