Browsing by Author "Dincer, Ibrahim"

Now showing 1 - 18 of 18

Citation - Scopus: 9
Assessment of Maisotsenko combustion turbine cycle with compressor inlet cooler
(Springer International Publishing, 2015) Hakan Caliskan; I. Dincer; A. Hepbasli; Hepbasli, Arif; Dincer, Ibrahim; Caliskan, Hakan
In this study a Maisotsenko combustion turbine cycle (MCTC) with compressor inlet cooling system is proposed and studied through energy exergy and exergoeconomic analysis methods. The present system consists of a Maisotsenko air cooler a compressor a turbine a generator a combustor and a compressed air saturator. The results show that an exergy efficiency of 58.27 % is higher than the corresponding energy efficiency of 51.55 % for the MCTC system due to the fact that the exergy content of the fuel fed into the combustion chamber is lower than its energy content. Also the maximum exergy destruction rates occur in the compressor and turbine with the values of 166.964 kW and 150.864 kW respectively. Furthermore the exergoeconomic results indicate that the highest exergetic cost factor defined as the destruction in the component per cost is determined to be 0.013148 kW/$ for the turbine while the Maisotsenko cycle air cooler has a minimum rate of 0.000006 kW/$. The better optimization of this component may be considered. It is concluded that Maisotsenko cycle systems can be effectively integrated to turbine cycle systems. Also energy exergy and exergoeconomic analyses give more useful information together about assessing the MCTC system and minimizing the thermodynamic inefficiencies. © 2017 Elsevier B.V. All rights reserved.
Citation - WoS: 73
Citation - Scopus: 80
Comparative assessment of various chlorine family thermochemical cycles for hydrogen production
(PERGAMON-ELSEVIER SCIENCE LTD, 2016) M. Tolga Balta; Ibrahim Dincer; Arif Hepbasli; Hepbasli, Arif; Balta, M. Tolga; Dincer, Ibrahim
This study deals with a comparative assessment of various chlorine family cycles namely copper chlorine (CuCl) magnesium-chlorine (MgCl) iron-chlorine (Fe-Cl) and vanadium-chlorine (V-Cl) cycles which are driven by heat and/or electricity. Hydrogen production through thermochemical and/or hybrid cycles can play a significant role in reducing greenhouse gas emissions and hence offering opportunities for better environment and sustainability. In this paper we conduct energy and exergy analyses of the VCl cycle and examine both energy and exergy efficiencies of the cycle. We also undertake a parametric study to investigate how the overall cycle performance is affected by changing the reference environment temperature and cycle operating conditions. The performance of VCl cycle are evaluated and compared with CuCl MgCl and FeCl cycles. Furthermore these cycles are discussed and compared with each other through their advantages and challenges. As a result VCl cycle offers a good potential due to its high efficiency over 40% based on a complete reaction. In this regard VCl cycle appears to be one of the most promising low temperature cycles. It may therefore compete with other low temperature cycles such as copper-chlorine. (C) 2016 Hydrogen Energy Publications LLC. Published by Elsevier Ltd. All rights reserved.
Citation - WoS: 78
Citation - Scopus: 81
Energy and exergy analyses of a hybrid hydrogen energy system: A case study for Bozcaada
(Elsevier Ltd, 2017) Yildiz Kalinci; I. Dincer; A. Hepbasli; Hepbasli, Arif; Kalinci, Yildiz; Dincer, Ibrahim
In the study a hybrid energy system for hydrogen and electric production is conceptually developed and applied to an island Bozcaada. A thermodynamic analysis is performed using energy and exergy approaches. The conceptual system is examined from the viewpoints of economic and energy load distributions by the Hybrid Optimization Model for Electric Renewable (HOMER) tool. In the study stand-alone island model is selected for analysis scenarios. The model consists of photo voltaic (PV) array wind turbines electrolyzer polymer electrolyte membrane fuel cell (PEMFC) hydrogen tank and converter. Energy and exergy analyses are applied to determine of the locations and magnitudes of system inefficiencies. The analyses are essentially made for the main equipment under dynamically changing operating and environmental conditions. In addition hourly distributions of changing energy and exergy rates are illustrated. As a result the daily average energy and exergy efficiencies of the PV array are 13.31% and 14.26%. Also the efficiency values are calculated for the wind turbine as 46% for energy and 50.12% for exergy and the electrolyzer equipment as 59.68% for energy and 60.26% for exergy respectively. © 2017 Elsevier B.V. All rights reserved.
Citation - WoS: 111
Citation - Scopus: 129
Energy exergy and sustainability analyses of hybrid renewable energy based hydrogen and electricity production and storage systems: Modeling and case study
(Elsevier Ltd, 2013) Hakan Caliskan; I. Dincer; A. Hepbasli; Hepbasli, Arif; Dincer, Ibrahim; Caliskan, Hakan
In this study hybrid renewable energy based hydrogen and electricity production and storage systems are conceptually modeled and analyzed in detail through energy exergy and sustainability approaches. Several subsystems namely hybrid geothermal energy-wind turbine-solar photovoltaic (PV) panel inverter electrolyzer hydrogen storage system Proton Exchange Membrane Fuel Cell (PEMFC) battery and loading system are considered. Also a case study based on hybrid wind-solar renewable energy system is conducted and its results are presented. In addition the dead state temperatures are considered as 0 °C 10 °C 20 °C and 30 °C while the environment temperature is 30 °C. The maximum efficiencies of the wind turbine solar PV panel electrolyzer PEMFC are calculated as 26.15% 9.06% 53.55% and 33.06% through energy analysis and 71.70% 9.74% 53.60% and 33.02% through exergy analysis respectively. Also the overall exergy efficiency ranging from 5.838% to 5.865% is directly proportional to the dead state temperature and becomes higher than the corresponding energy efficiency of 3.44% for the entire system. © 2017 Elsevier B.V. All rights reserved.
Citation - Scopus: 5
Environmental impact assessment of building energy systems
(Springer New York, 2013) Mustafa Tolga Balta; I. Dincer; A. Hepbasli; Balta, M. Tolga; Dincer, Ibrahim; Hepbasli, Arif; Caliskan, Hakan
This chapter deals with energy/exergy and environmental analyses of a low exergy heating system. A building with a volume of about 392 m3and a floor area of 140 m2is presented as a case study. For this building four different heating options are investigated namely (1) electric boiler (2) ground heat pump system (3) standard boiler and (4) solar collector. In this regard an energy and exergy analysis is employed to assess their performances and compare them through energy and exergy efficiencies. Also CO2 NOx SO2emissions of the considered systems are determined and compared with each other. Overall exergy efficiencies of the heating systems are found to be 4.0 10.1 7.6 and 35.7 %. CO2 NOx SO2emissions rate per year (kg emission/year) calculated for considered cases as 10726.32 4224.17 3737.56 and 337.67 11.14 4.39 3.40 and 3.35 and 116.34 45.82 3.68 and 3.66 respectively. The lowest environmental impact is provided by case 4. © 2017 Elsevier B.V. All rights reserved.
Citation - Scopus: 4
Exergetic performance assessment of a binary geothermal power plant
(Springer International Publishing, 2014) Yildiz Kalinci; A. Hepbasli; I. Dincer; Hepbasli, Arif; Kalinci, Yildiz; Dincer, Ibrahim
Electricity generation is achieved by means of the medium-temperature geothermal water in the range of 90–140 ºC in binary plants with the organic Rankine cycle. So we investigate a binary geothermal power plant as a case study from the energy and exergy point of view. Also exergy destruction rates throughout the plant are quantified and illustrated for comparison purposes. In the plant considered the brine injection and reinjection temperatures are 140 and 80 ºC with a mass flow rate of 64.87 kg/s respectively. The energy and exergy efficiencies are calculated as 5.34 and 30.84 % respectively based on the heat and exergy input rates to the system at the net power. Furthermore we examine the effects of some parameters on energy and exergy efficiencies and net power output (e.g. brine injection temperature brine mass flow rates turbine inlet temperature and inlet pressure). © 2017 Elsevier B.V. All rights reserved.
Citation - WoS: 26
Citation - Scopus: 32
Exergoeconomic analysis and performance assessment of hydrogen and power production using different gasification systems
(Elsevier Sci Ltd, 2012) Yildiz Kalinci; A. Hepbasli; I. Dincer; Hepbasli, Arif; Kalinci, Yildiz; Dincer, Ibrahim
In this paper we investigate three different gasifiers for hydrogen production namely downdraft gasifier (DG) circulating fluidized bed gasifier (CFBG) and plasma gasifier (PG) as taken from the literature under Cases 1-3 respectively. These cases are then modified for cogeneration of hydrogen and power. We use the specific exergy cost (SPECO) method to calculate exergy-related parameters and display cost flows for all streams and components. The case studies are selected from different countries. We study how flow rates of streams cost and hydrogen unit costs change if these facilities operate in Turkey. The process life time is considered 15 years and the inflation rate and energy inflation rate are taken from the Central Bank of the Republic of Turkey as 8.91% and 19.25% while unit energy water and biomass costs are taken 31.38 $/GJ 4.59 $/t and 35.42 $/t for Turkey respectively. The electric power requirements are calculated to be 0.0915 12.53 and 23.26 MW e for DG CFBG and PG respectively. In Cases 1-3 the electric power generated by the systems are 0.144 MW 1.17 MW and 3.88 MW respectively and may be sold to the national grid with cost rates of 31.8 $/h 258.39 $/h and 856.88 $/h. In the systems the hydrogen production rates and costs per unit mass are obtained to be 0.004 kg/s 0.521 kg/s and 0.155 kg/s and 1.16 $/kg 3.33 $/kg and 2.45 $/kg for the DG the CFBG and the PG respectively. © 2012 Elsevier Ltd. All rights reserved. © 2012 Elsevier B.V. All rights reserved.
Citation - WoS: 21
Citation - Scopus: 27
Exergoeconomic analysis of hydrogen production from biomass gasification
(PERGAMON-ELSEVIER SCIENCE LTD, 2012) Yildiz Kalinci; Arif Hepbasli; Ibrahim Dincer; Hepbasli, Arif; Kalinci, Yildiz; Dincer, Ibrahim
In this study we investigate biomass-based hydrogen production through exergy and exergoeconomic analyses and evaluate all components and associated streams using an exergy cost energy and mass (EXCEM) method. Then we define the hydrogen unit cost and examine how key system parameters affect the unit hydrogen cost. Also we present a case study of the gasification process with a circulating fluidized bed gasifier (CFBG) for hydrogen production using the actual data taken from the literature. We first calculate energy and exergy values of all streams associated with the system exergy efficiencies of all equipment and determine the costs of equipment along with their thermodynamic loss rates and ratio of thermodynamic loss rate to capital cost. Furthermore we evaluate the main system components consisting of gasifier and PSA from the exergoeconomic point of view. Moreover we investigate the effects of various parameters on unit hydrogen cost such as unit biomass and unit power costs and hydrogen content of the syngas before PSA equipment and PSA hydrogen recovery. The results show that the CFBG system which has energy and exergy efficiencies of 55.11% and 35.74% respectively generates unit hydrogen costs between 5.37 $/kg and 1.59 $/kg according to the internal and external parameters considered. Copyright (C) 2012 Hydrogen Energy Publications LLC. Published by Elsevier Ltd. All rights reserved.
Citation - WoS: 67
Citation - Scopus: 75
Exergoeconomic and environmental impact analyses of a renewable energy based hydrogen production system
(Pergamon-Elsevier Science Ltd, 2013) Hakan Caliskan; I. Dincer; A. Hepbasli; Hepbasli, Arif; Dincer, Ibrahim; Caliskan, Hakan
In this study exergoeconomic and environmental impact analyses through energy exergy and sustainability assessment methods are performed to investigate a hybrid version renewable energy (including wind and solar) based hydrogen and electricity production system. The dead state temperatures considered here are 10 °C 20 °C and 30 °C to undertake a parametric study. An electrolyzer and a metal hydride tank are used for hydrogen production and hydrogen storage respectively. Also the Proton Exchange Membrane Fuel Cell (PEMFC) and battery options are utilized for electricity generation and storage respectively. As a result the energy and exergy efficiencies and the sustainability index for the wind turbine are found to be higher than the ones for solar photovoltaic (PV) system. Also the overall exergy efficiency of the system is found to be higher than the corresponding overall energy efficiency. Furthermore for this system it can be concluded that wind turbine with 60 gCO2/month is more environmentally-benign than the solar PV system with 75 gCO2/month. Finally the total exergoeconomic parameter is found to be 0.26 W/$ when the energy loss is considered while it is 0.41 W/$ when the total of exergy loss and destruction rates are taken into account. Copyright © 2013 Hydrogen Energy Publications LLC. Published by Elsevier Ltd. All rights reserved. © 2013 Elsevier B.V. All rights reserved.
Citation - WoS: 138
Citation - Scopus: 156
Exergoeconomic- enviroeconomic and sustainability analyses of a novel air cooler
(ELSEVIER SCIENCE SA, 2012) Hakan Caliskan; Ibrahim Dincer; Arif Hepbasli; Hepbasli, Arif; Dincer, Ibrahim; Caliskan, Hakan
This study presents the energy exergy environmental exergoeconomic enviroeconomic and sustainability analyses of the Maisotsenko cycle based novel air cooler considering the nine different dead state temperatures while the environment temperature is kept constant. In the energy analysis the wet bulb and dew point effectivenesses cooling capacity energetic coefficient of performance and primary energy ratio rates are calculated. Also in the exergy analysis exergy input output loss and destruction rates as well as exergetic coefficient of performance and primary exergy ratio and exergy efficiency values are determined. Furthermore sustainability analysis of the system is conducted through a sustainability index method. The electrical energy consumption cost of this novel air cooler shows that it consumes only 59.85 $/year when it is operated 8 h a day and 125 days in a year. The maximum exergetic cost rate is found to be 0.0228 kWh/$-year at a dead state temperature of 37.77 degrees C. Also according to the enviroeconomic (environmental cost) analysis this novel air cooler has very CO2 emissions cost as 6.96 $/year. Consequently these results show the originality of the Maisotsenko cycle based novel air cooler. (C) 2012 Elsevier B.V. All rights reserved.
Letter to Editor: Rebuttal to "some comments to the paper 'Energy exergy and sustainability analyses of hybrid renewable energy based hydrogen and electricity production and storage systems: Modeling and case study'"
(Elsevier Ltd, 2013) Hakan Caliskan; I. Dincer; A. Hepbasli; Hepbasli, Arif; Dincer, Ibrahim; Caliskan, Hakan
[No abstract available]
Citation - WoS: 107
Citation - Scopus: 125
Life cycle assessment of hydrogen production from biomass gasification systems
(Pergamon-Elsevier Science Ltd, 2012) Yildiz Kalinci; A. Hepbasli; I. Dincer; Hepbasli, Arif; Kalinci, Yildiz; Dincer, Ibrahim
In this study a Life Cycle Assessment (LCA) of biomass-based hydrogen production is performed for a period from biomass production to the use of the produced hydrogen in Proton Exchange Membrane (PEM) fuel cell vehicles. The system considered is divided into three subsections as pre-treatment of biomass hydrogen production plant and usage of hydrogen produced. Two different gasification systems a Downdraft Gasifier (DG) and a Circulating Fluidized Bed Gasifier (CFBG) are considered and analyzed for hydrogen production using actual data taken from the literature. Fossil energy consumption rate and Green House Gas Emissions (GHG) are defined and indicated first. Next the LCA results of DG and CFBG systems are compared for 1 MJ/s hydrogen production to compare with each other as well as with other hydrogen production systems. While the fossil energy consumption rate and emissions are calculated as 0.088 MJ/s and 6.27 CO2 eqv. g/s in the DG system they are 0.175 MJ/s and 17.13 CO2 eqv. g/s in the CFBG system respectively. The Coefficient of Hydrogen Production Performance (CHPP) (newly defined as a ratio of energy content of hydrogen produced from the system to the total energy content of fossil fuels used) of the CFBG and DG systems are then determined to be 5.71 and 11.36 respectively. Thus the effects of some parameters such as energy efficiency ratio of cost of hydrogen on natural gas and capital investments efficiency are investigated. Finally the costs of GHG emissions reduction are calculated to be 0.0172 and 0.24 $/g for the DG and CFBG systems respectively. © 2012 Hydrogen Energy Publications LLC. Published by Elsevier Ltd. All rights reserved. © 2013 Elsevier B.V. All rights reserved.
Citation - WoS: 24
Citation - Scopus: 28
Performance assessment of hydrogen production from a solar-assisted biomass gasification system
(PERGAMON-ELSEVIER SCIENCE LTD, 2013) Yildiz Kalinci; Arif Hepbasli; Ibrahim Dincer; Hepbasli, Arif; Kalinci, Yildiz; Dincer, Ibrahim
In this study we investigate a solar-assisted biomass gasification system for hydrogen production and assess its performance thermodynamically using actual literature data. We also analyze the entire system both energetically and exergetically and evaluate its performance through both energy and exergy efficiencies. Three feedstocks namely beech charcoal sewage sludge and fluff are considered as samples in the same reactor. While energy efficiencies vary from 14.14% to 27.29% exergy efficiencies change from 10.43% to 23.92%. We use a sustainability index (SI) as a function of exergy efficiency to calculate the impacts on sustainable development and environment. This index changes from 1.12 to 1.31 due to intensive utilization of solar energy. Also environmental impact of these systems is evaluated through calculating the specific greenhouse gas (GHG) emissions. They are determined to be 17.97 17.51 and 26.74 g CO2/MJ H-2 for beech charcoal sewage sludge and fluff respectively. Copyright (C) 2013 Hydrogen Energy Publications LLC. Published by Elsevier Ltd. All rights reserved.
Citation - WoS: 40
Citation - Scopus: 47
Performance assessment of solar-driven integrated Mg-Cl cycle for hydrogen production
(Elsevier Ltd, 2014) Mustafa Tolga Balta; I. Dincer; A. Hepbasli; Hepbasli, Arif; Balta, M. Tolga; Dincer, Ibrahim
The present study develops a new solar energy system integrated with a Mg-Cl thermochemical cycle for hydrogen production and analyzes it both energetically and exergetically for efficiency assessment. The solar based integrated Mg-Cl cycle system considered here consists of five subsystems such as: (i) heliostat field subsystem (ii) central receiver subsystem (iii) steam generation subsystem (iv) conventional power cycle subsystem and (v) Mg-Cl subsystem. Also the inlet and outlet energy and exergy rates of all of subsystems are calculated and illustrated accordingly. We also undertake a parametric study to investigate how the overall system performance is affected by the reference environment temperature and operating conditions. As a result the overall energy and exergy efficiencies of the considered system are found to be 18.18% and 19.15% respectively. The results show that the Mg-Cl cycle has good potential and attractive overall cycle efficiencies over 50%. © 2021 Elsevier B.V. All rights reserved.
Citation - WoS: 296
Citation - Scopus: 321
Techno-economic analysis of a stand-alone hybrid renewable energy system with hydrogen production and storage options
(PERGAMON-ELSEVIER SCIENCE LTD, 2015) Yildiz Kalinci; Arif Hepbasli; Ibrahim Dincer; Hepbasli, Arif; Kalinci, Yildiz; Dincer, Ibrahim
In the present study a hybrid renewable energy system using hydrogen energy as energy storage option is conceptually modeled for the Bozcaada Island in Turkey. The system is investigated from the techno-economic point of view. The Hybrid Optimization Model for Electric Renewable (HOMER) tool is used to define the optimum size of the equipment based on the geographical and meteorological data of the island. The HOMER uses the net present cost (NPC) method while ranking the system suitability. Also the cost of energy (COE) is calculated with the total annual cost (ACT). The study considers two scenarios which are only wind turbine and wind turbine/PV hybrid systems. Using the wind turbine/PV array system instead of wind turbine only decreases the NPC from $14624343 to $11960698. Also it decreases the hydrogen tank capacity to 400 kg and hence affects other equipment size and NPC. So the COE varies between $1.016/kWh and $0.83/kWh. According to this the optimum system components are defined as PV array-300 kW wind turbine (E33x2) fuel cell-100 kW converter-150 kW electrolyzer-200 kW and hydrogen tank-400 kg to supply a 1875 kWh/d primary load. Furthermore the effects of some parameters and the equipment on NPC are examined. Increasing potential of the renewable energy sources such as annual average wind speed or solar radiation decreases both COE and NPC. While the annual average solar radiation increases to 5 kWh/m(2)/d the NPC and CUE decrease to $11673704 and $0.81/kWh. Likewise an increase in the annual average wind speed will decrease the costs to $11452712 and $0.795/kWh respectively. Also increasing the real interest i to 5% increases the COE to $1.043/kWh as expected. Copyright (c) 2014 Hydrogen Energy Publications LLC. Published by Elsevier Ltd. All rights reserved.
Citation - WoS: 75
Citation - Scopus: 81
Thermodynamic analyses and assessments of various thermal energy storage systems for buildings
(Pergamon-Elsevier Science Ltd, 2012) Hakan Caliskan; I. Dincer; A. Hepbasli; Hepbasli, Arif; Dincer, Ibrahim; Caliskan, Hakan
In this study energetic exergetic environmental and sustainability analyses and their assessments are carried out for latent thermochemical and sensible thermal energy storage (TES) systems for phase change material (PCM) supported building applications under varying environment (surrounding) temperatures. The present system consists of a floor heating system System-I System-II and System-III. The floor heating system stays at the building floor supported with a floor heating unit and pump. The System-I includes a latent TES system and a fan. The latent TES system is comprised of a PCM supported building envelope in which from outside to inside, glass transparent insulation material PCM air channel and insulation material are placed respectively. Furthermore System-II mainly has a solar-thermochemical TES while there are an aquifer TES and a heat pump in System-III. Among the TESs the hot and cold wells of the aquifer TES have maximum exergetic efficiency values of 88.782% and 69.607% at 8°C dead state temperature respectively. According to the energy efficiency aspects of TESs the discharging processes of the latent TES and the hot well of the aquifer TES possess the minimum and maximum values of 5.782% and 94.118% at 8°C dead state temperature respectively. Also the fan used with the latent TES is the most environmentally-benign system component among the devices. Furthermore the most sustainable TES is found for the aquifer TES while the worst sustainable system is the latent TES. © 2012 Elsevier Ltd. All rights reserved. © 2012 Elsevier B.V. All rights reserved.
Thermodynamic analysis of geothermally driven high-temperature steam electrolysis system for hydrogen production
(Springer International Publishing, 2014) Mustafa Tolga Balta; I. Dincer; A. Hepbasli; Hepbasli, Arif; Balta, Mustafa Tolga; Dincer, Ibrahim
Hydrogen production by high-temperature steam electrolysis (HTSE) has been receiving increasing attention worldwide due to its high efficiency and carbon-free operation. Although it is still considered in its early developmental stage it offers a promising solution for highly efficient hydrogen production. From the thermodynamic viewpoint of water decomposition it is more advantageous to electrolyse water at high temperatures because the energy is supplied in mixed form of electricity and heat. In this study a HTSE process coupled with and powered by a geothermal power plant is considered for analysis and assessment and as a case study. In this regard its thermodynamic analysis through energy and exergy is conducted for performance evaluation and comparison purposes. As a result compared to conventional water electrolysis the operation at high temperatures reduces the electrical energy requirement for the electrolysis and also increases the efficiency. © 2017 Elsevier B.V. All rights reserved.
Citation - WoS: 25
Citation - Scopus: 27
Thermoeconomic analysis of a building energy system integrated with energy storage options
(Pergamon-Elsevier Science Ltd, 2013) Hakan Caliskan; I. Dincer; A. Hepbasli; Hepbasli, Arif; Dincer, Ibrahim; Caliskan, Hakan
This study deals with exergetic and thermoeconomic analyses of thermal energy storage (TES) systems such as latent sensible and thermochemical options coupled with different units for building heating applications under varying reference (dead-state) temperatures of 8 C 9 C and 10 C respectively. It is found that the variation reference temperature affects the thermoeconomic parameters. The exergetic cost of the system becomes higher at the higher reference conditions as directly proportional to the varying dead state conditions. It also becomes minimum at 8 C reference temperature as 196.96 $/h while it is maximum at 10 C dead-state temperature with 357.60 $/h. Furthermore the maximum capital cost of the equipment is determined for the thermochemical TES as 4.612 $/h. So the better optimization of this equipment may be considered. © 2013 Elsevier Ltd. All rights reserved. © 2013 Elsevier B.V. All rights reserved.