scholarly journals Evaluation and Optimization of the Annual Performance of a Novel Tri-Generation System Driven by Geothermal Brine in Off-Design Conditions

2020 ◽  
Vol 10 (18) ◽  
pp. 6532
Author(s):  
Mehri Akbari Kordlar ◽  
Florian Heberle ◽  
Dieter Brüggemann
Keyword(s):  
Exergy Efficiency ◽  
Working Fluid ◽  
Exergy Destruction ◽  
Operational Parameters ◽  
Generation System ◽  
Geothermal Resources ◽  
Kalina Cycle ◽  
Destruction Rate ◽  
Heating And Cooling ◽  
The Difference

The difference in heating or cooling to power ratio between required demands for district networks and the proposed tri-generation system is the most challenging issue of the system configuration and design. In this work, an adjustable, novel tri-generation system driven by geothermal resources is proposed to supply the thermal energies of a specific district network depending on ambient temperature in Germany. The tri-generation system is a combination of a modified absorption refrigeration cycle and a Kalina cycle using NH3-H2O mixture as a working fluid for the whole tri-generation system. A sensitive analysis of off-design conditions is carried out to study the effect of operational parameters on the system performances prior to optimizing its performance. The simulation show that the system is able to cover required heating and cooling demands. The optimization is applied considering the maximum exergy efficiency (scenario 1) and minimum total exergy destruction rate (scenario 2). The optimization results show that the maximum mean exergy efficiency in scenario 1 is achieved as 44.67% at the expense of 14.52% increase in the total exergy destruction rate in scenario 2. The minimum mean total exergy destruction rate in scenario 2 is calculated as 2980 kW at the expense of 8.32% decrease in the exergy efficiency in scenario 1.

scholarly journals Energy and Cost Analysis and Optimization of a Geothermal-Based Cogeneration Cycle Using an Ammonia-Water Solution: Thermodynamic and Thermoeconomic Viewpoints

2020 ◽  
Vol 12 (2) ◽  
pp. 484 ◽  
Author(s):  
Nima Javanshir ◽  
Seyed Mahmoudi S. M. ◽  
M. Akbari Kordlar ◽  
Marc A. Rosen
Keyword(s):  
Water Solution ◽  
Unit Cost ◽  
Exergy Efficiency ◽  
Hot Water ◽  
Cycle Performance ◽  
Working Fluid ◽  
Kalina Cycle ◽  
Ammonia Water ◽  
Total Product ◽  
Cogeneration Cycle

A cogeneration cycle for electric power and refrigeration, using an ammonia-water solution as a working fluid and the geothermal hot water as a heat source, is proposed and investigated. The system is a combination of a modified Kalina cycle (KC) which produces power and an absorption refrigeration cycle (ARC) that generates cooling. Geothermal water is supplied to both the KC boiler and the ARC generator. The system is analyzed from thermodynamic and economic viewpoints, utilizing Engineering Equation Solver (EES) software. In addition, a parametric study is carried out to evaluate the effects of decision parameters on the cycle performance. Furthermore, the system performance is optimized for either maximizing the exergy efficiency (EOD case) or minimizing the total product unit cost (COD case). In the EOD case the exergy efficiency and total product unit cost, respectively, are calculated as 34.7% and 15.8$/GJ. In the COD case the exergy efficiency and total product unit cost are calculated as 29.8% and 15.0$/GJ. In this case, the cooling unit cost, c p , c o o l i n g , and power unit cost, c p , p o w e r , are achieved as 3.9 and 11.1$/GJ. These values are 20.4% and 13.2% less than those obtained when the two products are produced separately by the ARC and KC, respectively. The thermoeconomic analysis identifies the more important components, such as the turbine and absorbers, for modification to improve the cost-effectiveness of the system.

Exergoenvironmental Analysis of Tetrahydrofuran/Ethanol Separation through Extractive and Pressure-Swing Distillation

2020 ◽  
Vol 0 (0) ◽  
Author(s):  
Patrick Vaz Mangili ◽  
Diego Martinez Prata
Keyword(s):  
Carbon Emissions ◽  
Extractive Distillation ◽  
Exergy Destruction ◽  
Fuel Type ◽  
Ethanol Mixture ◽  
Destruction Rate ◽  
High Boiling Point ◽  
The Difference ◽  
Pressure Swing ◽  
Pressure Swing Distillation

AbstractExtractive distillation uses a high-boiling point solvent for changing the relative volatility of the azeotropic mixture, whereas pressure-swing distillation is based on the difference of operating pressures for such a purpose. In this paper, said separation technologies were applied to a tetrahydrofuran/ethanol mixture and compared with regard to their thermodynamic and environmental performances. The former was assessed by determining the total exergy destruction rate and rational efficiency of each configuration, while the latter was evaluated by estimating their respective indirect carbon emissions. The results showed that the pressure-swing process has not only the lowest exergy destruction rate (383.1 kW) but also the lowest CO2 emission rate (678.7 kg/h), which is mainly due to its lower thermal energy requirements. A sensitivity analysis was then carried out in order to determine how the carbon emissions respond to both the efficiency and the fuel type of the utility boiler.

Exergy Analysis of Solar Photovoltaic/Thermal Organic Rankine Cycle

2013 ◽  
Vol 448-453 ◽  
pp. 1509-1513 ◽  
Author(s):  
Guo Chang Zhao ◽  
Li Ping Song ◽  
Yong Wang ◽  
Xiao Chen Hou
Keyword(s):  
Exergy Analysis ◽  
Organic Rankine Cycle ◽  
Rankine Cycle ◽  
Exergy Efficiency ◽  
Solar Thermal ◽  
Working Fluid ◽  
Solar Photovoltaic ◽  
Generation System ◽  
Cycle System ◽  
Power Generation System

A solar thermal organic Rankine cycle (ORC) power generation system model established using R245fa as the working fluid and coupled with a solar photovoltaic generator is introduced. Thermal efficiency and exergy efficiency of the model both with and without a heat regenerator are calculated and compared. Results show the solar organic Rankine cycle system with a heat regenerator has higher thermal and exergy efficiency than the system without a heat regenerator, providing better performance in practice. This result provides a basis for further application and improvement of solar photovoltaic and the solar thermal organic Rankine cycle.

Modeling and Exergy and Exergoeconomic Optimization of a Gas Turbine Power Plant Using a Genetic Algorithm

2010 ◽  
Author(s):  
Soheil Fouladi ◽  
Hamid Saffari
Keyword(s):  
Genetic Algorithm ◽  
Power Plant ◽  
Combustion Chamber ◽  
Gas Turbine ◽  
Exergy Efficiency ◽  
Design Parameters ◽  
Working Fluid ◽  
Exergy Destruction ◽  
The Cost ◽  
Gas Turbine Power Plant

In this paper, the thermodynamic modelling of a gas turbine power plant in Iran is performed. Also, a computer code has been developed based on Matlab software. Moreover, both exergy and exergoeconomic analysis of this power plant have been conducted. To have a good insight into this study, the effects of key parameters such as compressor pressure ratio, gas turbine inlet temperature (TIT), compressor and turbine isentropic efficiency on the total exergy destruction, total exergy efficiency as well as total cost of exergy destruction have been performed. The modelling results have been compared with an actual running power plant located in Yazd city, Iran. The results of developed code have shown reasonable agreement between the simulation code results and experimental data obtained from power plant. The exergy analysis revealed that the combustion chamber is the must exergy destructor in comparison with other components. Also, its exergy efficiency is less than other components. This is due to the high temperature difference between working fluid and burner temperature. In addition, it was found that by the increase of TIT, the exergy destruction of this component can be reduced. On the other hand, the cost of exergy destruction is high for the combustion chamber. The effects of design parameters on exergy efficiency have shown that increase in the air compressor ratio and TIT, increases the total exergy efficiency of the cycle. Furthermore, the results have revealed that by the increase of TIT by 350°C, the cost of exergy destruction is decreased about 22%. Therefore, TIT is the best option to improve the cycle losses. In addition, an optimization using a genetic algorithm has been conducted to find the optimal solution of the plant.

Performance Evaluation of the Thermophotovoltaic-Driven Thermoionic Refrigerator

2019 ◽  
Vol 142 (3) ◽  
Author(s):  
Emin Açıkkalp ◽  
Süheyla Yerel Kandemir ◽  
Mohammad H. Ahmadi
Keyword(s):  
Energy Source ◽  
Performance Evaluation ◽  
Solar Energy ◽  
Cooling Rate ◽  
Power Output ◽  
Exergy Efficiency ◽  
Exergy Destruction ◽  
Destruction Rate ◽  
Operation Conditions

Abstract In this study, the thermophotovoltaic (TPV)-driven thermionic refrigerator (TIR) is presented as an alternative refrigerator operated by the solar energy. Solar energy is the main energy source and its performance is analyzed. Power output density of the TPV, cooling rate density, COP, exergy destruction rate densities, and exergy efficiencies are the considered parameters. Calculations are performed numerically; results are presented and discussed. The most suitable operation conditions are defined. According to the results, the cooling rate density is 648 W/m2, power output densities are 1189.86 W/m2 and 667.234 W/m2 for the eg = 0.3 eV and eg = 0.4 eV, and the exergy efficiency of the system is about 0.071.

scholarly journals Investigation of an Innovative Cascade Cycle Combining a Trilateral Cycle and an Organic Rankine Cycle (TLC-ORC) for Industry or Transport Application

Energies ◽  
2018 ◽  
Vol 11 (11) ◽  
pp. 3032 ◽  
Author(s):  
Xiaoli Yu ◽  
Zhi Li ◽  
Yiji Lu ◽  
Rui Huang ◽  
Anthony Roskilly
Keyword(s):  
High Temperature ◽  
System Performance ◽  
Organic Rankine Cycle ◽  
Rankine Cycle ◽  
Exergy Efficiency ◽  
Working Fluid ◽  
Second Law ◽  
Exergy Destruction ◽  
Second Law Analysis ◽  
Net Power Output

An innovative cascade cycle combining a trilateral cycle and an organic Rankine cycle (TLC-ORC) system is proposed in this paper. The proposed TLC-ORC system aims at obtaining better performance of temperature matching between working fluid and heat source, leading to better overall system performance than that of the conventional dual-loop ORC system. The proposed cascade cycle adopts TLC to replace the High-Temperature (HT) cycle of the conventional dual-loop ORC system. The comprehensive comparisons between the conventional dual-loop ORC and the proposed TLC-ORC system have been conducted using the first and second law analysis. Effects of evaporating temperature for HT and Low-Temperature (LT) cycle, as well as different HT and LT working fluids, are systematically investigated. The comparisons of exergy destruction and exergy efficiency of each component in the two systems have been studied. Results illustrate that the maximum net power output, thermal efficiency, and exergy efficiency of a conventional dual-loop ORC are 8.8 kW, 18.7%, and 50.0%, respectively, obtained by the system using cyclohexane as HT working fluid at THT,evap = 470 K and TLT,evap = 343 K. While for the TLC-ORC, the corresponding values are 11.8 kW, 25.0%, and 65.6%, obtained by the system using toluene as a HT working fluid at THT,evap = 470 K and TLT,evap = 343 K, which are 34.1%, 33.7%, and 31.2% higher than that of a conventional dual-loop ORC.

scholarly journals Exergy Analysis of Kalina and Kalina Flash Cycles Driven by Renewable Energy

2020 ◽  
Vol 10 (5) ◽  
pp. 1813
Author(s):  
Kyoung Hoon Kim ◽  
Hyung Jong Ko ◽  
Chul Ho Han
Keyword(s):  
Exergy Analysis ◽  
Power Production ◽  
Ammonia Concentration ◽  
Exergy Efficiency ◽  
Low Grade ◽  
Heat Sources ◽  
Exergy Destruction ◽  
Kalina Cycle ◽  
Low Grade Heat ◽  
Exergy Performance

The Kalina cycle (KC) has been recognized as one of the most efficient conversion systems of low-grade heat sources. The Kalina flash cycle (KFC) is a recently proposed novel cycle which is equipped with an additional flash process to the KC. In this study, the exergy performance of KC and KFC driven by a low-grade heat source are investigated comparatively. The dependence of the exergy destruction at each component as well as the system’s exergy efficiency on ammonia concentration, separator pressure and, additionally, flash pressure for KFC, are systematically investigated. Results showed that KFC can be optimized with respect to flash pressure on the base of exergy efficiency, and the component where largest exergy destruction occurs varies for different separator pressure and ammonia fraction in both systems. It is also shown that the maxima of net power production and exergy efficiency in KFC with optimal flash pressure are superior to those in KC.

scholarly journals Thermodynamic Analysis and Systematic Comparison of Solar-Heated Trigeneration Systems Based on ORC and Absorption Heat Pump

Energies ◽  
2021 ◽  
Vol 14 (16) ◽  
pp. 4770
Author(s):  
Jesús García-Domínguez ◽  
J. Daniel Marcos
Keyword(s):  
Heat Pump ◽  
Electrical Power ◽  
Organic Rankine Cycle ◽  
Systematic Investigation ◽  
Exergy Efficiency ◽  
Operating Conditions ◽  
Working Fluid ◽  
Simultaneous Generation ◽  
Absorption Heat Pump ◽  
Heating And Cooling

Modular and scalable distributed generation solutions as combined cooling, heating and power (CCHP) systems are currently a promising solution for the simultaneous generation of electricity and useful heating and cooling for large buildings or industries. In the present work, a solar-heated trigeneration approach based on different organic Rankine cycle (ORC) layouts and a single-effect H2O/LiBr absorption heat pump integrated as a bottoming cycle is analysed from the thermodynamic viewpoint. The main objective of the study is to provide a comprehensive guide for selecting the most suitable CCHP configuration for a solar-heated CCHP system, following a systematic investigation approach. Six alternative CCHP configurations based on single-pressure and dual-pressure ORC layouts, such as simple, recuperated and superheated cycles, and their combinations, and seven organic fluids as working medium are proposed and compared systematically. A field of solar parabolic trough collectors (SPTCs) used as a heat source of the ORC layouts and the absorption heat pump are kept invariant. A comprehensive parametric analysis of the different proposed configurations is carried out for different design operating conditions. Several output parameters, such as energy and exergy efficiency, net electrical power and electrical to heating and cooling ratios are examined. The study reveals that the most efficient CCHP configuration is the single-pressure ORC regenerative recuperated superheated cycle with toluene as a working fluid, which is on average 25% and 8% more efficient than the variants with single-pressure simple cycle and the dual-pressure recuperated superheated cycle, respectively. At nominal design conditions, the best performing CCHP variant presents 163.7% energy efficiency and 12.3% exergy efficiency, while the electricity, cooling and heating productions are 56.2 kW, 223.0 kW and 530.1 kW, respectively.

scholarly journals Energetic and Exergetic Assessment of the Cooling Efficiency of Automobile Radiator Using Mono and Hybrid Nanofluids

2021 ◽  
Vol 39 (4) ◽  
pp. 1321-1327
Author(s):  
Khalid Faisal Sultan ◽  
Hosham salim Anead ◽  
Ameer Abed Jaddoa
Keyword(s):  
Heat Transfer ◽  
Fluid Velocity ◽  
Exergy Efficiency ◽  
Working Fluid ◽  
Hybrid Nanofluid ◽  
Exergy Destruction ◽  
Current Form ◽  
Nano Fluid ◽  
Hybrid Nanofluids ◽  
Primary Form

In this paper, for two separate half-breed Nano liquids, Ag (25nm) + refined water and Ag (50nm) + Zn (50nm)-refined water tentatively considered at the vehicle radiator, the execution of restricted convection. Four distinct cross-breed Nano liquid concentrations in the range of 2-6 vol %. The increase of half breed nanoparticles into the refined water as a base liquid was organized by percentage. Within the range of 20 l/min-60 l /min, the coolant flow rate is altered. Inside the warm trade, Crossover Nano coolants show colossal change compared to the refined water. Ag-refined water cross breed Nano liquid's warm exchange execution was found to be much better than Ag + Zn-refined water half breed Nano coolant. In addition, with the rise in the concentration of half breed nanoparticle and half breed Nano fluid velocity, the Nusselt number is found to expand. In the advancement of the warm exchange rate, Mono and hybrid nanofluid forms play a very important role in enhancing the heat transfer and refrigeration of car radiators. With an increase in concentration of half-breed nanoparticles for the primary form about 44 percent warm exchange transition, expansion of 6 vol percent crossover nanoparticles were achieved with the rate of warm exchange. In comparison to the current form of cross breed nanoparticles, with an expansion of 6 percent vol concentration, 22 percent extended. The exergy in flow, exergy destruction and exergy efficiency of mono nanofluid (Ag +Dw) are greater than hybrid nanofluid (Ag + Zn + Dw) and distilled water. The exergy inflow, exergy destruction, and exergy efficiency as the concentration of nanoparticles increases for the two forms of mono and hybrid nanofluid. The values parameters of the mono nanofluid (Ag + Dw) such as exergy in flow, exergy destruction and exergy efficiency at 6 vol% were 572 W, 460 W, 72% respectively while in hybrid nanofluids (Ag + Zn + Dw) were 420W, 282W, 51%. The use of mono and hybrid nanofluid as a working fluid results in higher efficiency of heat transfer, which promotes the performance of the car engine and decreases fuel consumption.

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