Kyushu University Academic Staff Educational and Research Activities Database
List of Papers
SAEID JALILINASRABADY Last modified date:2022.06.28

Associate Professor / Department of Earth Resources Engineering / Faculty of Engineering

1. Bett Alvin Kiprono, Saeid Jalilinasrabady, Application of reservoir exergy profile analysis by wellbore simulation on Olkaria Domes geothermal field, Geothermics, 10.1016/j.geothermics.2022.102478, 105, 102478, 2022.11, [URL], Geothermal is the energy for the future and is eco-friendly. Exergy analysis of geothermal power plants has been referenced based on wellhead and surface environment conditions. Previous studies have not linked the surface and sub-surface in Olkaria and other geothermal fields worldwide. The wellbore simulator connected the wellhead, and the reservoir simulated pressure and temperature logs for Olkaria Domes in Olkaria, a liquid-dominated geothermal field. The simulation results enabled the calculation of exergy values at any depth using the pressure and temperature between the reservoir and wellhead. Obtained results of the research used to interpret heat transfer between geothermal reservoir layers and the location of the reservoir. This study takes the exergy analysis to the source of geothermal brine under saturated conditions. The paper presents exergy profiles of geothermal wells at Olkaria Domes. The field data input parameters were wellhead pressure, mass flow rates of steam and brine, wellbore diameter, and the reservoir depths (deeper/second and shallow). A wellbore model developed in 1988 was used to simulate temperature-pressure profiles. The thermodynamic parameters (temperature and pressure) from the wellbore simulator were input parameters in the Engineers Equation Solver (EES) code to calculate entropy, enthalpy, and specific exergy. The wellbore exergy profiles show estimated feed zone depths of -1000 - (-) 2800 m.a.s.l for two-directional and three vertical wells. The profiles predicted convective and conductive heat transfers points. For wellhead temperatures of between 182 -205°C, the reservoir temperatures from the wellbore simulator are high at 292°C. The formation pressures were between 3,978 to 7,710 kPa. Exergy wellbore simulation of the geothermal reservoir predicted the reservoir and heat transfers in the sub-surface. The study demonstrates the importance of connecting the reservoir and wellhead via a wellbore simulation and exergy profiles..
2. NA Pambudi, VS Pramudita, MK Biddinik, Saeid Jalilinasrabady, So Close Yet so Far – How People in the Vicinity of Potential Sites Respond to Geothermal Energy Power Generation: an Evidence from Indonesia, Evergreen, , 9, 1, 1-9, 9, 1,1-9, 2022.03, [URL], Presently, Indonesia aims to reduce greenhouse gas (GHG) from 29 to 40% before 2030 by growing the use of renewable energy. One of the sources of renewable energy is geothermal by expanding the development in several locations. This study, therefore, aims to examine the public knowledge, attitude, and perception on the development of Geothermal Energy Power Generation in Mount Lawu, Central of Java. This descriptive and qualitative research showed that most people's understanding of geothermal energy was insignificant. Therefore, the result showed that the majority perception had limited knowledge in geothermal energy. During this research, the local government had not implemented the Mount Lawu geothermal energy generation development. The community and local government are considering the pros and cons of the project, which is the main reason for the project implementation delay. Furthermore, the responses in addressing the geothermal plant project generally fell into three categories: agree, disagree, and doubt. There is some Society's consent that formed based on accepting the positive side of the plant. Furthermore, the initial negative response was due to their poor relationship with the project activities and the absence of prior information. Another factor was their sense of fear and doubt on the positive impacts of the project shortly..
3. Alvin Kiprono Bett and Saeid Jalilinasrabady, Exergy profile analysis by wellbore simulation, 47th Workshop on Geothermal Reservoir Engineering, Stanford University, 47, 47 , 1-8, 2022.02, [URL], This paper presents exergy in the wellbore. Exergy analysis is considered between the wellhead to the reservoir with geothermal brine at saturated conditions. The field data input parameters were wellhead pressure, mass flow rates of steam and brine wellbore diameter, and the reservoir depths (deeper/2nd depth and shallow). The pressure-temperature (PT) profile was simulated using the wellbore model developed in 1988. The exergy profiles estimated feed zone depths of -1000 - (-)2800 m.a.s.l for a directional well. The research investigated liquid-dominated Olkaria Domes wells, OW-901, OW-902 and OW-903A. The profiles predicted convective and conductive heat transfers points. For wellhead temperatures of between 160 and 184oC, the reservoir temperatures from the wellbore simulator are high at 250oC in OW-913A, and formation pressure is between 3,978 kPa. The formation pressures simulated are between 1,077 to 12,487.9 kPa for wellhead pressure of 459 to 1,720 kPa. The thermodynamic parameters (temperature and pressure) from the wellbore simulator were input parameters in the EES code. The calculated values in EES were entropy, enthalpy, and specific exergy. Exergy wellbore simulation of the geothermal reservoir predicted the geological stratification of the geothermal field. The study demonstrates the importance of connecting the reservoir and wellhead via a wellbore simulation and exergy profiles..
4. Saeid Jalilinasrabady, Toshiaki Tanaka, Ryuichi Itoi, Hiroki Goto, Numerical simulation and production prediction assessment of Takigami geothermal reservoir, ENERGY, 10.1016/, 236, 2021.12, A numerical model was developed for the Takigami geothermal reservoir. A conceptual model of the field was constructed, initial and boundary conditions were defined according to available data. For the optimum model, permeability values of assigned rock types, mass flow rates, enthalpies, and locations of recharge zones were estimated according to matching between computed temperature for wells and their temperature profiles before the exploitation. Observed and calculated temperature profiles confirmed the validity of the conceptual model. The best model could successfully reproduce the initial temperature profiles of 13 wells located mainly in the production area. A developed model was used as an initial model for future prediction of the reservoir performance. The prediction simulation was conducted by assuming two different development scenarios for the Takigami geothermal power plant. Scenario I was continuing the current power production. Scenario II was to investigate producing 8.6 MWe more electricity by employing bottoming binary cycle to the currently under operation single flash plant. Effects of production and reinjection temperatures under proposed development scenarios were evaluated. Simulation results indicated that most probably there is no direct interaction between reinjection and production zones in the Takigami reservoir,and installing a binary plant will not have any severe impact on reservoir performance..
5. Saeid Jalilinasrabady, Performance evaluation of geothermal power plants, Transactions - Geothermal Resources Council, GRC 2021, 45, 1399-1413, 2021.10, [URL], Geothermal energy is a renewable energy resource, but its sustainability heavily depends on development methods and smart resource management. Optimum utilization of geothermal resources in line with cascaded uses are the key parameters that can lead to the sustainable development of the resources. Plant optimization is one of the standard tools for its performance evaluation. As a result of optimization, energy and exergy efficiencies are very useful to give an idea about resource management to investors and decision-makers for an individual plant performance analysis. Comparing different plants could be challenging due to many contributing parameters such as local ambient conditions and individual plant specifications. This paper will perform energy and exergy analysis for the Takigami geothermal power plant in Japan. Then the results will be compared with published results from selected plants worldwide to present a sensible unified parameter that is independent of the plant's local conditions..
6. Alvin Kiprono Bett and Saeid Jalilinasrabady , Optimization of ORC Power Plants for Geothermal Application in Kenya by Combining Exergy and Pinch Point Analysis , Energies,, 14, 20, 2021.10, [URL], Geothermal energy is a sustainable renewable source of energy. The installed capacity of geothermal energy in Kenya is 847.4 MWe of the total 2.7 GWe. This paper presents the effect of six different working fluids to optimize the geothermal of 21.5 MWe of reinjected brine at a single-flash power plant in Kenya. Engineering Equation Solver (EES) code was used to design and optimize simple organic Rankine (ORC) and regenerative cycles. The objective was to combine pinch point analysis and exergy analysis for the optimum utilization of geothermal energy by varying the turbine inlet pressure, pinch point, and reinjection temperature. The turbine inlet pressures, and pinch points were varied to obtain optimum pressures for higher net power output and exergy efficiencies. As the pressure increased, the efficiencies and net power generated increase to optimal at turbine inlet pressures between 2000 and 3000 kPa. By maintaining a condenser temperature at 46.7 °C, the turbine outlet pressures were 557.5 kPa for isobutene, 627.4 kPa for isobutane, 543.7 kPa for butene, 438.9 kPa for trans-2-butene, 412.3 kPa for R236ea, and 622.9 kPa for R142b. For the pinch point of 10 °C, the working fluid with a lower net power is trans-2-butene at 5936 kW for a flow rate of 138.8 kg/s and the highest reinjection at 89.05 °C. On the other hand, R236ae had a flow rate of 398.2 kg/s, a higher power output of 7273 kW, and the lowest reinjection temperature of 73.47 °C for a 5 °C pinch point. In the pinch point consideration, the suitable fluid will depend on the best reinjection temperatures. The pinch point affects the heat transfer rates and effectiveness in the heat exchangers. The best pinch point is 10 °C, since the reinjection temperatures are the highest between 83 and 89 °C. The analysis showed that for unlimited reinjection temperatures, basic ORC is suitable. The regenerative cycle would be best suited where reinjection temperature is constrained by brine geochemistry..
7. Alvin Kiprono Bett, Saeid Jalilinasrabady, Maria Zhahata Geraldinne Malana, LCOE and exergoeconomic analysis of air-cooled binary power plant, Transactions - Geothermal Resources Council, GRC 2021 , 45, 1389-1398, 2021.10, [URL], Geothermal binary power plants can be utilized using low-grade resources. As power plants being thermal conversion units, there is a need to combine economics and exergy optimization from the available energy resource. This study analyzed isobutane air-cooled binary power plants at different geothermal brine temperatures at 187oC, 156oC, and 120oC, accordingly. The geothermal binary power plant was designed and analyzed using Engineering Equation Solver (EES) code and System Advisor Model (SAM). Further, it was optimized by different turbine inlet pressure, and EES results which are the basis to Levelized Cost of Electricity (LCOE) calculations. The exergy efficiencies were obtained between 20-35%. Thermal efficiencies were between 6 - 9.5%, and LCOE varied between 0.079 and 0.099 $/kWh. It is important to combine thermo-economic, exergy, and LCOE in power plant design for optimum utilization of available resource..
8. John Ngethe, Saeid Jalilinasrabady, Potential of cascaded use of geothermal energy to uplift fish production in Kenyan aquaculture, Transactions - Geothermal Resources Council, GRC 2021, 2021.10, [URL], Kenya's population in 2020 was 52m and projected to be 70m by 2033 thus raising demand for food by a factor of 10-15%. Currently, the Kenyan food basket relies on poultry and fish for white meat. The poultry is derived from small-scale farmers while the fish are obtained from Lake Victoria, Lake Naivasha, Lake Turkana and the Indian Ocean. Unfortunately, the lakes mentioned have longstanding challenges of overfishing and their fish production, 100, 000MT/yr on average, has been declining over time. Lack of advanced fishing vessels in the Indian Ocean limits Kenyan ability to scrape up significant marine fish. In 2019, Kenyan aquaculture produced about 20, 000MT of fish from artificial ponds at a backdrop of a countrywide annual demand of 700, 000MT. Besides, the Kenyan fish industry faces additional challenges of limited coldhandling facilities for chilling the fish from the source to the markets since most fish production areas are off the grid. The traditional alternatives for cold storage systems in Kenya are fishsmoking and sun-drying which dehydrate the fish to lengthen the shelf life, compromising on taste and sanitation. This paper looks into the various ways injection of geothermal energy into aquaculture in Kenya could improve production. The paper also compares the competitiveness of geothermal energy to solar energy for suitability to powering aquaculture. As the direct utilization of geothermal energy is localized near the resource or in locations with significant geothermal gradients, the paper seeks to rank the best locations for energy boosted aquaculture in Kenya and those regions that are best suited for other renewable energy sources; solar, wind and biomass..
9. Alvin Kiprono Bett, Saeid Jalilinasrabady , Life cycle assessment of geothermal sources in Kenya, Transactions - Geothermal Resources Council, GRC 2021, 45, 1620-1625, 2021.10, [URL], Power generation is a source of environmental pollutants globally. In Kenya, energy sources are mainly renewable. A life cycle assessment (LCA) of geothermal energy is presented for five geothermal power plants calculated using a geothermal LCA calculator developed by Argonne National Laboratory. The metrics calculated for electricity generation were greenhouse gas ratios, fossil energy, and material to power ratio (MPR). MPR values for different materials consumed were cement between 73-417 MT/MW and steel between 102-464 MT/MW. Energy input in development contributed mainly to greenhouse gas emissions of between 1.115-3.189 g/kWh. LCA in prospecting fields reduces the environmental impacts and aims at a higher drilling success rate..
10. Alvin Kiprono Bett, Saeid Jalilinasrabady, Energy & Exergy Analysis for Proposed Olkaria II Binary Power Plant in Relation to Sustainability Index for Different Working Fluids, Journal of the Geothermal Research Society of Japan,, 43, 3, 111-121, 2021.07, [URL], Geothermal energy is a renewable energy source with low carbon footprint. In Olkaria geothermal field - Kenya, single flash geothermal power plants have been analyzed mainly by energy criteria. Olkaria II geothermal power plant generates 105 MWe and reinjects the brine which contains the exergy of 19,685 kW. This paper applied energy and exergy analysis techniques to investigate a proposed binary power plant using Engineering Equation Solver (EES), by introducing sustainability index (SI) and isentropic effectiveness. Eight working fluids were selected for the study. The paper investigated the exergy destruction in the plant under ambient conditions (86 kPa and 20oC) with varying turbine inlet pressure and reinjection temperatures. Heat exchangers contributed about 60% (between 2,900 - 4,200 kW) of total exergy destruction. The second utilization efficiencies were between 26-45%. Sustainability indices were between 1.24 and 1.53 with reinjection temperatures above 78oC. Isobutane and R600a had sustainability indices of 1.52 and 1.53 with power generation of 6,791 and 6,792 kW, respectively. Trans-2-butene as a working fluid generated 5,790 kWe with thermal, exergy, and second utilization efficiencies of 11.67%, 29.41% and 45.18%, respectively with a better reinjection temperature of 99.14oC. It was revealed that using trans-2-butene working fluid resulted in the lowest exergy destruction. Grassman exergy flow diagram showed reinjected exergy and network generated were the main proportions of the total exergy into the system. Also, it was observed that, for both the isobutane and R600a systems, the optimum operating condition for maximum net output power are similar..
11. Kiprono Bett Alvin, Saeid Jalilinasrabady, Exergoeconomic Analysis for Optimized Combined Wet and Dry Cooling BinaryPower Plant at Olkaria I, Kenya, Geothermics,, 95, 102160, 95, 2021.06, [URL], This study investigated a complete exergoeconomic comparison of wet and dry-cooled binary power plants. Simple organic Rankine cycles (ORC) for Olkaria geothermal field in Kenya using eight isobutane types of working fluids were proposed for analysis by the thermo-economic concept and sustainability index (SI). Network generated per heat transfer surface area was the optimized objective function, f(obj). Variable metric optimization method implemented in Engineers Equation Solver (EES) was applied to optimize plants for average fuel cost for geothermal fluid at 1.3 $/GJ. The exergoeconomic of the cooling tower contributed mainly to the investment cost of a water-cooled plant. Network of 1,628 kWe to 2,594 kWe was generated in wet cooled unit with SI of 1.654 to 2.701 for f(obj) of 1.5 to 1.8. For air-cooled plant, SI ranges were from 1.286 to 1.612 for the network from 1,446 kWe to 2,469 kWe with utilization efficiency of 34.77% to 59.37% and f(obj) values of 0.56 to 0.89. The cost of products range was from 18.3 $/GJ to 20.76 $/GJ for wet system and from 20.87 $/GJ to 23.4 $/GJ for dry-cooling. Selection of the suitable power plant based on exergoeconomic would be air-cooled systems with lower plant's cost rates of between 76.92 $/hr and 135.8 $/hr. The heat capacities are 20,806-20,610 kW for isobutene, 24,153-23,928 kW for isobutane, 13,727-13,595 kW for cis-2-butene and, 16,772-16,611 kW for n-butane for ambient temperatures between 0°C and 40°C. Application of air-cooled units would be advisable where water is scarce and in colder regions. Thermo-economic concept concludes that complete exergoeconomic of power plants presents a better investment decision by variable metric optimization method..
12. S. M. Alirahmi, E. Assareh, A. Chitsaz, Saeid Jalilinasrabady, S. Ghazanfari, Electrolyzer-fuel cell combination for grid peak load management in a geothermal power plant: Power to hydrogen and hydrogen to power conversion, International Journal of Hydrogen Energy,, 2021.05, [URL], This study provides comprehensive energy, exergy, and economic evaluations and optimizations of a novel integrated fuel cell/geothermal-based energy system simultaneously generating cooling and electricity. The system is empowered by geothermal energy and the electricity is mainly produced by a dual organic cycle. A proton exchange membrane electrolyzer is employed to generate the oxygen and hydrogen consumed by a proton exchange membrane fuel cell utilized to support the network during consumption peak periods. This fuel cell can be also used for supplying the electricity demanded by the network to satisfy the loads at different times. All the simulations are conducted using Engineering Equation Solver software. To optimize the system, a multi-objective optimization method based on genetic algorithm is applied in MATLAB software. The objective functions are minimized cost rate and maximized exergy efficiency. The optimum values of exergy efficiency and cost rate are found to be 62.19% and 18.55$/h, respectively. Additionally, the results reveal that combining a fuel cell and an electrolyzer can be an effective solution when it comes to electricity consumption management during peak load and low load periods..
13. E. Assareh, M. Assareh, SM. Alirahmi, Saeid Jalilinasrabady, A. Dejdar, M. Izadi, An extensive thermo-economic evaluation and optimization of an integrated system empowered by solar-wind-ocean energy converter for electricity generation – Case study: Bandar Abas, Iran, Thermal Science and Engineering Progress,, 25, 100965, 25, 2021.05, [URL], n parallel with efforts to shift human societies' reliance from fossil fuel to renewable resources, in this paper, three green-based energy generation configurations were proposed and examined thermoeconomically. Afterwards, the one with the highest performance was selected for further investigation. The chosen system was empowered by an ocean thermal energy convertor (OTEC), a wind turbine, and a solar flat plate panel. The system was modeled by Engineering Equation Solver (EES) software to conduct sensitivity analysis by assessing the impact of changes in objective parameters on the net power output, thermoelectric generator (TEG) power output, exergy efficiency, and cost ratio. In the following steps, EES was coupled with MATLAB through Dynamic Data Exchange (DDE), and a non-dominated sorting genetic algorithm (NSGA-II) was employed for optimizing design parameters including solar panels' area, organic Rankine cycle (ORC) turbine inlet temperature, condenser outlet temperature, ORC pump and turbine efficiency, TEG figure of merit, and evaporator pinch point to reach the highest possible exergy efficiency and the least amount for cost ratio. The system performed with 13.88% exergy efficiency. The exergy destruction analysis showed wind turbine was the most exergy destructor in the system. The configuration is able to generate 448 kW power at its optimal point. Eventually, a case study for Bandar Abbas city, a coastal town in the south of Iran, is carried out to investigate the system's performance concerning the region's potential throughout a year. The results indicate that the system can potentially supply 38 Iranian households with electricity all year-round..
14. John Ngethe, Saeid Jalilinasrabady, Optimization of Geothermal Greenhouses Design for Kenyan Fresh-cut Flowers, 46th Workshop on Geothermal Reservoir Engineering, Stanford University, 2021.02, [URL], Kenya is among the top countries that export fresh-cut flowers to Europe, Russiaand China. The fresh-cut flower farming involves greenhouses to limit evapotranspiration and for ease of disease and pest control. Since these activities are labor-intensive, flower farming employs a significant number of farmhands which accounts for more than a tenth of employment provided by the Kenyan agricultural sector. Unfortunately, flower farms use lots of chemical pesticides, fungicides and herbicides, some of which find itself in local freshwater lakes and rivers. One farm, Oserian Development Company, situated near Olkaria geothermal field uses brine to heat its greenhouses thus saving a lot on chemical fungicides by raising dew-point temperatures that occur at 0100-0600 hours. The greenhouse warming reduces humidity levels from 100% to 85% the chances of dew forming on leaves thus limiting the growth of fungi. This research paper seeks to optimize the greenhouse design for both optimal flower growth and dew-point eradication. Besides, the paper integrates cascaded use of geothermal greenhouses with absorption chillers for cooling of fresh-cut flowers thus maximizing brine utilization and saving on electricity for running the coolers. Since a significant number of fresh-cut flower farms are located near developed geothermal prospects, coupling the two will enhance the performance of flower growing and reduce the overall cost thus making Kenyan flowers competitive price-wise in global markets..
15. Mirmahdi Seyedrahimi-Niaraqa, Faramarz Doulati Ardejanib, Younes Noorollahic, Saeid Jalili Nasrabadi, Amin Hekmatnejade, An unsaturated three-dimensional model of fluid flow and heat transfer in NW Sabalan geothermal reservoir, Geothermics, 10.1016/j.geothermics.2020.101966, 89, 2021.01, [URL], This paper presents a 3D numerical model for the north-west (NW) Sabalan geothermal system, including the unsaturated vadose zone overlying the system, based on a conceptual model derived from data gathered from 10 deep exploration wells. To achieve the goal, the EOS3 (water-air state equation) module of the Tough2 simulator was utilized to develop the model. The model was constructed from a rectangular prism, which is 11.5 km long, 8 km wide, and variable depths ranging from 3.8–5.11 km. The 21 horizontal layers with a thickness range of 100−1000 m were expanded from the maximum height of 4110 to -1000 masl. A total of 22 rock types were distributed within the model based on the availability of rock units and geological structures derived from the exploration wells. The permeability of these rock types varied from 1.0 × 10−17 to 9.0 × 10-13 m2. The model was initially run to match the natural state of the reservoir. A close agreement was obtained between the measured data from the exploration wells, and the model results for subsurface temperatures and pressures. In the calibrated model, a high temperature upflow zone was required in the southeast part of the area (below the exploration sites D and E). This flow rises to the land surface through permeable zones, faults, and fractures, and finally appears on the earth’s surface as hot springs in the northwestern part of the area. This model was then used as the initial model to predict the reservoir performance for the 50 MWe scenario. The results showed that the reservoir can generate about 45 MWe by assigning two makeup wells and remain at this level for more than 30 years..
16. Alvin Kiprono Bett, Saeid Jalilinasrabady, Leonard K Langat, Exergonomic Analysis of Topping Unit at Olkaria IV Geothermal Power Plant , International Symposium on Earth Science and Technology, CINEST 2020, Fukuoka, Kyushu University, 2020.12.
17. Minami Kai, Saeid Jalilinasrabady, Ryuichi Itoi , Numerical Modeling and Optimization of the Geo-Wind Hybrid Power Generation, International Symposium on Earth Science and Technology, CINEST 2020, Fukuoka, Kyushu University, 2020.12.
18. Ngethe John, Saeid Jalilinasrabady, Analysis of Land Use Within Close Proximity of Menengai Geothermal Resource in Kenya via Remote Sensing, International Symposium on Earth Science and Technology, CINEST, Fukuoka, Kyushu University, 35-41, 2020.12, The direct use of geothermal energy is highly dictated by economics, thermal needs and quality of thermal energy available. Several economic parameters that dictate the viability of direct utilization of geothermal resources are the availability of; sustainable thermal energy demand, brine piping routes that encourage brine flow via gravity and an efficient flow rate of brine to match the thermal demand as well as short brine piping distances. The current research work analyses thermal demand near geothermal resources via remote sensing of agricultural activities and urban development. Clustering of crop type and crop-calendars will help in analyzing the viability of crop drying, greenhouse warming and aquaculture using geothermal energy. Urban density clustering aided in decision making on cascaded use of geothermal energy from industrial processing of agricultural goods to urban-heating and recreational spas. This research work seeks to identify thermal needs and match them to available geothermal resources via GIS mapping. The results show that the Menengai prospect is best suited for crop drying, industrial processing, spa and district heating. Priority being in that order..
19. Maria Zhahata Geraldinne Malana, Ariel Fronda, Saied Jalilinasrabady, Alvin Kiprono, Energy and exergy analysis of BN-06 wellhead geothermal power plant in province of Biliran, Philippines, Transactions - Geothermal Resources Council, 44, 1003-1017, 2020.10, Biliran I Geothermal Project is one of the promising yet undeveloped intermediate-enthalpy geothermal resource in the Philippines. There were already drilled wells in the project site and in this paper, Well BN-06D was selected to evaluate its maximum power generation through exergy analysis. Exergy analysis is a tool which analyzes geothermal power plants from the optimum perspective of produced energy and it delivers sensible values for decision makers. Moreover, combined single flash-binary cycle has been chosen to utilize the power output capacity. Wellbore output measurements from the successful Fluid Management System (FMS) and mathematical models, were applied in Engineers Equation Solver (EES). Assumptions and simplifications were also considered. The energy efficiency from the combined single flash-binary cycle was calculated at 10.77%. Further, the exergy efficiency from the single flash and waste brine were calculated at 37.87% and 31.83%, respectively. By using binary cycle, the waste brine was utilized, and the exergy efficiency was increased to 37.90%. The large exergy destruction in the systems happened in condenser under single flash cycle (22%), pre-heater under binary cycle (15%) and both turbines; (9.8% in binary & 8% in single flash). A Grassmann diagrams were also illustrated to further visualize the process of the overall exergy flow in each system..
20. Bett Alvin Kiprono, Saeid Jalilinasrabady, K Langat Leonard, Energy and exergy analysis of olkaria domes field: Well head and single flash power plants comparison, Transactions - Geothermal Resources Council, 44, 980-989, 2020.10, Kenya is ranked 5th globally in geothermal development. Geothermal exploration started around 1950's in Olkaria and Bogoria. In power plant development, the main parameters applied are power generated and exergy, among others. Well head installation in Olkaria was adopted in 2012 has a total installed capacity of 81 MWe. The well head units in Olkaria are all single flash type. Single flash are the main power plants globally. In this study exergy analysis and parametric comparison of conventional single flash generating 142 MWe and well head of 7 MWe is presented. The plants are optimized based on maximum power generated, highest efficiencies and lower parasitic loads with the focus on the non-condensable gas removal. The obtained results show that well head and single flash operates in the same trend with different optimization objectives. Well head has the best exergy efficiency at 64% and least exergy destroyed in the separator..
21. John Ngethe, Saeid Jalilinasrabady, Considering future feasible agricultural projects for direct use of geothermal energy at eburru geothermal field, Transactions-Geothermal Resources Council, 268-283, Volume 44, 2020.10, Direct use of geothermal energy is highly dictated by economics, thermal needs and quality of thermal energy available. Among the factors that discourage direct use is prohibitive costs of brine piping, low probability of project sustainability as well as the remote location of geothermal resources. To overcome these challenges, it is crucial to match geothermal resources with local thermal needs and settle with applications that request minimal piping and pumping of brine, with fewer or zero well drilling and with minimal environmental impacts. This paper tackles these challenges through thermal load identification, via crop-calendar at Eburru geothermal field. The available exploration geothermal wells are matched to possible application scenarios and the best application scenario chosen through the Analytical Hierarchy Process (AHP). The most economical crop drying plant should be located near well EW-01, (Site A), with a shallow percolation pond as a dumping option for exhausted brine..
22. Bett Alvin K., LANGAT Leonard K, Rop Eric K, Jalilinasrabady Saeid, Optimization of Olkaria II Geothermal Brine for a Proposed Binary Unit by Energy and Exergy Analysis, World Geothermal Congress, WGC 2020+1, Iceland, 2020.04.
23. Alvin K. Bett, Eric K. Rop, Saeid Jalilinasrabady, Ryuichi Itoi, Energy and Exergetic Analysis of a Proposed Olkaria I Binary Geothermal Power Plant, Naivasha, Kenya, World Geothermal Congress (WGC) 2020+1, 2020.04.
24. Seyed Zahed Mousavi, Saeid Jalilinasrabady, Geothermal Country Update Report of Iran (2015- 2020), World Geothermal Congress, WGC 2020+1, Iceland, 2020.04.
25. S. Jalilinasrabady, Sustainable development challenges in geothermal and petroleum, 81st EAGE Conference and Exhibition 2019 81st EAGE Conference and Exhibition 2019, 2019.06, Due to the dwindling sources of oil and gas, its role in fueling conflict coupled with global warming concerns, emphasis has shifted to finding alternative energy sources. Geothermal energy is one of the most plausible choices, majorly because it's renewable, sustainable and environmentally friendly. . Both energy resources originate from the earth and a number of techniques in the exploration and development of geothermal are a brain child of Oil and gas. These however have not been deployed without alteration in geothermal due to difference in the reservoir formations of both energies. Geothermal mines heat while oil mines fluid. A quick understanding and comparative study of the nature of these energies ascertain the feasibility of geothermal replacing oil and gas reveals that the principal difference between the two energies is sustainability and though feasible, geothermal is unable presently to replace oil and gas in the transport sector. It further illuminates the hurdles encompassing geothermal development such as high drilling costs that translate into escalated costs of geothermal energy and how the solutions are still strongly intertwined with oil and gas..
26. Mirmahdi Seyedrahimi-Niaraq, Faramarz Doulati Ardejani, Younes Noorollahi, Soheil Porkhial, Ryuichi Itoi, Saeid Jalilinasrabady, A three-dimensional numerical model to simulate Iranian NW Sabalan geothermal system, Geothermics, 10.1016/j.geothermics.2018.08.009, 77, 42-61, 2019.01, The plan for electricity generation from north-west (NW) Sabalan geothermal field, Iran has been presented since 1994. Now construction of the first pilot plant is running with a capacity of 5 MWe in this site. A three-dimensional (3D) numerical model of fluid flow and heat transfer of the geothermal reservoir was developed using Tough2 simulator code on the basis of the updated conceptual model from the field recent data. The aim of this study was to present an updated 3D model of the geothermal reservoir in this area by taking ten deep wells data into account and validate an existing model in which the data obtained from only three wells were included. The model covers an area of 92 km2 and extends to an approximate depth of 5.11 km from the land surface. The model includes 17 horizontal layers, (AA through QQ). The thickness of the layers range between 100 m and 1000 m. The model extends from a minimum level of -1000 to a maximum level of 4110 masl. The model has 12,784 grid blocks, in total. Each layer has 752 grid blocks with horizontal dimensions of 250 m × 250 m and 500 m × 500 m. Altogether, 21 rock types were used in the model to assign different horizontal permeability values from 1.0 × 10−17 to 9.0 × 10-13 m2 based on the conceptual model. The model was first calibrated by varying the permeability, the total magnitude and location of the recharges and well bottom pressure of discharge zones. It was further validated by the profiles of temperature and pressure distribution at 10 deep exploration wells data. A close agreement was obtained between the model predictions and the measured downhole temperature and pressure data in the exploration wells. In the best-fitted model, the natural state simulation proved the presence of a high temperature upflow zone in the southern part (Below the ground, between Pads D and E). High temperature fluid at a rate of 108 kg/s and with an enthalpy of 1056.43 kJ/kg (244 °C) recharged over an area of 2.25 km2 from 36 grid blocks from the bottom layer in southern part of the field. The overall natural discharge is about 43 kg/s from hot springs which was simulated using the pressure dependent deliverability method. The results show that there is mostly one inflow of geothermal water at the level of -1000 m at southeast below the land surface between the Pad D and Pad E. The fluid flow moves upward by the fracture zones and faults toward the northwest of area. The faults NW5, NW3 and NNW2 play a major role in this system. Finally, the geothermal fluid discharging by the surface manifestations can be seen as hot springs at the land surface. This model can be used to simulate future production scenarios to evaluate the sustainability of the reservoir..
27. Younes Noorollahi, Golara Ghasemi, Farshad Kowsary, Soheil Roumi, Saeid Jalilinasrabady, Modelling of heat supply for natural gas pressure reduction station using geothermal energy, International Journal of Sustainable Energy, 10.1080/14786451.2019.1585434, 2019.01, In this paper, a series of works are conducted to study the effect of replacing natural gas burning heaters by a ground source heat pumps (GSHPs) to prevent natural gas freezing in the pressure regulating stations. In fact, the pressure drop causes a great temperature drop that can block out the pipeline and it is very crucial to control the phenomenon. Firstly, a conventional heater in the gas pressure drop station of Damavand city is selected as a case study. Then, a shell and tube heat exchanger coupled with GSHP is modelled to replace the conventional heater for eliminating the natural gas consumption in heaters. Finally, consumed energy, costs, and greenhouse gasses emissions are compared with the conventional system. Some main findings from the model show that: (1). Based on the GS2000 software results, the GSHP pipe trench is 601 m which are 7% less than the calculated data. (2). considering different inflation rates (15%-30%), the payback time would change between 4.5 and 7.5 years. (3). Due to the reduction in fossil fuel consumption, the CO
emission would be reduced by 47%..
28. Saeid Mohammadzadeh Bina, Saeid Jalilinasrabady, Hikari Fujii, Hadi Farabi-Asl, A comprehensive approach for wind power plant potential assessment, application to northwestern Iran, Energy, 10.1016/, 164, 344-358, 2018.12, In the current study, the techno-environmental and economic feasibility analysis was conducted for prospective wind power plants in North West Iran. In order to assess the most appropriate and prospective wind farms, a Multi Criteria Decision Making (MCDM) technique in ArcGIS was used by applying the most important and effective environmental and technical criteria in the study area. Then, the obtained areas were classified on the basis of International Electrotechnical Commission (IEC) turbine classes using the wind speed map of the country to select the most appropriate wind turbine technology. The Weibull function was applied to model the wind behavior using actual meteorological data. The best fitted Weibull parameters including shape factor and mean wind speed were used in System Advisor Model (SAM) software to calculate the capacity factor for the three most promising regions of the study area at three different mast heights. The results indicated that around 9116 km2 was available as suitable area for wind turbine class III power plant implementation. Turbine Vestas V47 was chosen in order to estimate the amount of annual output energy, according to the achieved capacity factors condition. The total potential of annual generation was estimated to be 11,180.17 GWh, which can cover the majority of energy demand in the area. Finally, economic evaluation for this turbine showed that the generated power cost is around 0.15 $/kWh (4350 IRR/kWh). In the last step of this study, the amount of greenhouse gases reduction was calculated for each site..
29. Saeid Mohammadzadeh Bina, Saeid Jalilinasrabady, Hikari Fujii, Nugroho Agung Pambudi, Classification of geothermal resources in Indonesia by applying exergy concept, Renewable and Sustainable Energy Reviews, 10.1016/j.rser.2018.05.018, 93, 499-506, 2018.10, Indonesia is well-known for its reputation for possessing the world's largest geothermal potential, which has been characterized by high temperature geothermal resources’ concentration. The geothermal energy potential of Indonesia has been estimated to be 28,617 MW, which is about 40% of the world's geothermal potential. However, only about 4.5% is being utilized as electrical energy supply in this country. This paper comprises the Indonesian geothermal resources, based on their capability of doing work and efficiency. In this study, currently operating geothermal power plants in Indonesia have been classified, based on the exergy concept and the Specific Exergy Index (SExI). The results of SExI values show that nine geothermal fields are classified as high exergy resource with their SExI values exceeding 0.5, and two remaining power plants with SExI values between 0.05 and 0.5 are classified as medium geothermal resources..
30. Saeid Mohammadzadeh Bina, Saeid Jalilinasrabady, Hikari Fujii, Exergoeconomic analysis and optimization of single and double flash cycles for Sabalan geothermal power plant, Geothermics, 10.1016/j.geothermics.2017.10.013, 72, 74-82, 2018.03, In this study single and double flash systems were designed to utilize the Sabalan geothermal fluid as a heat source. An Exergoeconomic model was applied on plant’ equipment in order to calculate the thermodynamic and economic performances of the cycles. Parametric analysis was done to examine the effect of important key parameters including flash pressures and steam quality at turbine outlet on plant performance. Optimization process for maximum net power output was carried out on the plant using direct searching method in EES (Engineering Equation Solver). This process aimed to find the optimum flashing pressures corresponding to the maximum potential power output as an objective function. Additionally, the major exergy destruction locations were shown graphically and side by side for both systems to observe the effect of secondary flash process on exergy destruction at each component. Afterward, an environmental study was done in order to calculate the amount of fossil fuel saving and pollutants emission reduction compared to conventional fossil fuel power plants. The result showed that in double flash energy and exergy efficiency were increased from 16.26% and 40.06% to 17.73% and 50.89%, respectively. Moreover, double flash resulted in higher net power output compared to that of single flash (28,838 kW vs. 36,055 kW) while both cycles were using the same geofluid. Optimization results revealed that thermodynamically optimum cycle could not result the best and lower energy production cost and vice versa. Therefore, the single flash generates electricity within lower price compared to double flash system. Moreover, double flash considerably reduces the required fossil fuel and various pollutants emission more than single flash if they were replaced by fossil fuel power plants with same amount of production..
31. Nugroho Agung Pambudi, Ryuichi Itoi, Saeid Jalilinasrabady, Mert Gürtürk, Sustainability of geothermal power plant combined with thermodynamic and silica scaling model, Geothermics, 10.1016/j.geothermics.2017.09.003, 71, 108-117, 2018.01, This method of combining thermodynamic and silica scaling analysis aims to improve efficiency, power output and sustainability in geothermal power plants which suffer from high concentration of silica. The proposed method was employed in an analysis of the Dieng geothermal power plant. The process starts with a performance evaluation of the existing power plant system, which is comprised of many components where losses of both energy and exergy occur. Once the performance of the existing plant has been evaluated, optimization of operating parameters can be applied to maximize its power output without the expensive addition of any new components. The process then continues with the development of scenarios with the power plant's design, seeking potential methods to improve its performance. In these scenarios, the plant is expanded into a double flash system, single flash-binary and double flash-binary. Silica scaling behavior models are then applied to determine which is the best scenario for development. It was found that a double flash system is the best expansion scenario for Dieng Geothermal Power Plant. This scenario produces a high power output of 29,155 kW and the lowest excess deposit of silica at 899 ppm. Although this scenario produces lower power output than the double flash-binary system, it has less negative impact from silica scaling. By introducing this system, the company can obtain additional power output of 4855 kW..
32. Saeid Mohammadzadeh Bina, Saeid Jalilinasrabady, Hikari Fujii, Thermo-economic evaluation of various bottoming ORCs for geothermal power plant, determination of optimum cycle for Sabalan power plant exhaust, Geothermics, 10.1016/j.geothermics.2017.06.007, 70, 181-191, 2017.11, Thermo-Economic analysis was applied to four different arrangements of Organic Rankine Cycle, using dry organic fluid as working fluid. These cycles were designed to use the geothermal outlet of the Sabalan flash cycle as a heat source. Evaluations were made for the proposed systems to determine the effects of important operating parameters such as turbine inlet pressure, condenser temperature, pinch point temperature and mass flow rate of geofluid on energy and exergy efficiencies, as well as total production cost. Moreover, objective functions of this parametric study were to maximize energy and exergy efficiency levels and to minimize the total production cost. Optimal values of operating parameters were determined by EES optimization using the “variable metric” searching method and defining bounds for each variable as constraints. Among cycles, the maximum energy and exergy efficiency of 20.57% and 63.72% were calculated in the IHE-ORC. The obtained results from the cost optimization, revealed that the lowest energy production cost and the lowest total energy cost were calculated to be related to the R-ORC (25.1 $/GJ) and B-ORC (2.47 M$/year), respectively. The main aim of this study was to use of Fuzzy TOPSIS as Multi-Criteria Decision Making (MCDM) technique to rank cycles based on problem criteria of thermodynamic and economic performance. These criteria include: energy efficiency (N1), exergy efficiency (N2), net power output (N3), production cost (N4) and total cost rate (N5). The method of Interval Shannon's Entropy was used to determine weight values of the criteria automatically. Thus multi-criteria analysis showed that the IHE-ORC was the best system in Sabalan. Additionally, the Basic, Regenerative and Dual fluid ORC were ranked second, third and fourth respectively..
33. Khasani, Saeid Jalilinasrabady, H. Fujii, R. Itoi, Numerical study on the effects of wellhead restriction modes on the transient behaviors of a geothermal well deliverability applicable for short period of measurement, Geothermics, 10.1016/j.geothermics.2017.04.005, 69, 34-44, 2017.09, The transient behaviors of fluid, particularly on the stabilization time for a short period of artificial production test to establish deliverability curve is investigated numerically. Based on the experiences, the measured parameters, i.e. wellhead pressure and mass flow rate are taken when they are judged to be in stable condition. However, duration required for these variables to stabilize depends on flowing behavior of steam-water two-phase fluid in the wellbore. Additionally, the manner of controlling valve operation whether it starts from the well in full-opened condition or in full-closed condition seems to affect this flow stabilization. Thus, transient behaviors of well deliverability are analyzed numerically using a coupled reservoir-wellbore simulator. To evaluate the effects of the manner and the duration of valve controlling operation on well deliverability, a step change and linear changes with several time intervals in mass flow rate at the wellhead are given. The results show that for the same magnitude of flow rate increase and decrease changes, the fluid will stabilize faster for the condition when the valve operation starts from the well in opened condition in comparison to that in closed condition. Another result indicates that duration required for wellhead pressure to stabilize for a given mass flow rate increase in a form of step change is longer compared to that in the form of linear changes. The longer time applied for operating valve will result in the faster stabilization of wellhead pressure after operating valve is stopped..
34. Khasani, Saeid Jalilinasrabady, Toshiaki Tanaka, H. Fujii, R. Itoi, The study on transient behaviors of two-phase flow in a geothermal production well for a short period of continuous measurement, Experimental Thermal and Fluid Science, 10.1016/j.expthermflusci.2017.01.017, 84, 10-17, 2017.01, Deliverability of geothermal production wells is evaluated by measuring wellhead pressure versus mass flow rate at several wellhead pressures. Controlling a main valve of the well results in the changes in wellhead pressure and mass flow rate. However, duration required for these variables to stabilize depends on flowing behavior of steam-water two-phase fluid in the wellbore. Fluid stabilization seems to be an important parameter, mainly for short period of measurement. In addition, the manner of controlling valve operation whether it starts from the well in full-closed condition or in full-opened condition seems to affect this flow stabilization. Thus, the experiment was carried out for a production well 2H-21 at Hatchobaru geothermal field, Japan to verify these hypotheses. The measurement apparatus consisted of pressure sensors, water level sensor and a PC to store the measured data. The data were recorded every second for the pressures at upstream of the orifices, the pressure drops at the orifices, the pressures at the separators, and the water level at weir box. The degree of valve opening was changed three times during the measurement. Then, the duration of respective wellhead valve operation for controlling flow rate affecting the flow stabilization in wellbore was observed. It was found that quick valve operation caused longer period for stabilization and produced impulse response of flow rate soon after the valve operation stopped. The fluid flow required about 7 min to stabilize for closing valve operation whereas it needed longer than 20 min to reach the stable condition for opening valve operation. After changing the wellhead pressure, the steam flow rate stabilized quickly while the water flow rate showed a gradual change..
35. Saeid Mohammadzadeh Bina, Saeid Jalilinasrabady, Hikari Fujii, Energy, economic and environmental (3E) aspects of internal heat exchanger for ORC geothermal power plants, Energy, 10.1016/, 140, 1096-1106, 2017.01, Installing Internal Heat Exchanger (IHE) after the turbine, can increase the effectiveness of heat exchange process and consequently plant efficiency in the Organic Rankin Cycles (ORCs). The main objective of this study is to investigate and also compare the energy, economic and environmental issues for two different configurations of geothermal binary cycles including conventional ORC and ORC with Internal Heat Exchanger (IHE-ORC). Energy-Economic-Environment (3E) models for both cycles were developed and a parametric study was conducted with respect to the maximum thermodynamic efficiencies and minimum cost rate. Evaporator pressure, superheating degree of the steam, the minimum pinch difference temperature in the evaporator and also condenser temperature were analyzed to obtain the optimal performance of the system. The aim of this study was to investigate the effect of IHE in binary cycles on the exergy destruction rates for all components and finding the most sensitive equipment to IHE. The results indicated that under optimized economic conditions, IHE-ORC had higher net power output (5245 vs. 5063 kW) with lower production cost. Furthermore, IHE-ORC, had superior energy and exergy efficiencies (16.82%, 59.71% vs. 14.13%, 52.2%). Additionally, IHE system was more environmental friendly and in comparison with conventional ORC, it can save the fuel consumption by 3.6% higher value and consequently about 3.6% reduces the CO2 emission more than conventional ORC..
36. Saeid Mohammadzadeh Bina, Saeid Jalilinasrabady, Hikari Fujii, Thermo-economic evaluation and optimization of a regenerative orc cycle utilizing geothermal energy, Geothermal Resources Council 41st Annual Meeting - Geothermal Energy: Power To Do More, GRC 2017 Geothermal Energy Power To Do More - Geothermal Resources Council 2017 Annual Meeting, GRC 2017, 41, 2527-2539, 2017.01, Thermo-Economic analysis was applied for the Regenerative Organic Rankine Cycle utilizing geothermal fluid as a heat source. The considered cycle works with n-Pentane (R601) as a working fluid and uses geofluid at temperature and mass flow rate of 165° C and 100 kg/s, respectively. In order to optimize the cycle in terms of thermodynamics and economics, the important operation parameters such as evaporator pressure, condenser temperature, mass flow rate of geofluid and also pinch point temperature difference were considered. Moreover, the optimum values of parameters were calculated to maximize the thermodynamic efficiencies and minimize the production cost. The optimization process was carried out by direct method in EES (Engineering Equation Solver) to determine the optimum values of mentioned parameters as restriction criteria. The results showed that the cycle gives the highest energy and exergy efficiency of 19.93% and 60.98%, respectively. While the maximum energy output of 3,860 kW was obtained from optimized cycles based on economic considerations. Also, the maximum and minimum cost rate of 28.4 $/GJ and 25.1 $/GJ was estimated for the optimized cycle based on energy efficiency and economic, respectively..
37. Hikari Fujii, Hiroyuki Kosukegawa, Hadi Farabi-Asl, Saeid Jalilinasrabady, Experimental study on the applicability of ungrouted ground heat exchangers on thermal response tests, Journal of the Geothermal Research Society of Japan, 38, 2, 43-51, 2016.01, The applicability of ungrouted ground heat exchangers (GHEs) in thermal response tests (TRTs) has not been confirmed since TRTs are generally carried out in grouted GHEs. In this work, two TRTs were carried out in a 102 m GHE of 100 mm casing ID under ungrouted and grouted conditions. The TRT results were interpreted through the conventional graphical method and more advanced approach using the cylindrical source function and optical fiber thermometers. The interpretation results of thermal conductivity in the ungrouted and grouted GHE showed reasonably good matching in both interpretation methods, indicating the applicability of the TRTs to ungrouted GHEs for the optimum design and the development of potential maps of ground source heat pump systems..
38. Saeid Jalilinasrabady, Ryuichi Itoi, Nobuo Uchihori, Yoshihiro Okamura, Energy and exergy analysis of geothermal steam binary power generation, Geothermal Resources Council 2016 Annual Meeting - Geothermal Energy Here and Now: Sustainable, Clean, Flexible, GRC 2016 Geothermal Energy Here and Now Sustainable, Clean, Flexible - Geothermal Resources Council 2016 Annual Meeting, 40, 49-55, 2016, Scaling and corrosion have presented problems in many geothermal systems. Dissolved materials in geothermal waters can exhibit aggressive corrosive properties or have the tendency to deposit large amounts of mineral scale. Evaporators of binary cycles are a very important part of the system and their indirect contact with geothermal fluid is one of the methods to overcome aggressive behavior of these fluids. The idea of this project was to use separated steam in an evaporator as a heat source for binary plant. In this research, the experiment was designed and results were collected, a model was developed and validated using experimental data. Energy and exergy efficiencies of the proposed plant was calculated to be 7.42% and 35.14%, respectively..
39. Saeid Mohammadzadeh Bina, Saeid Jalilinasrabady, Hikari Fujii, Exergetic sensitivity analysis of orc geothermal power plant considering ambient temperature, Geothermal Resources Council 2016 Annual Meeting - Geothermal Energy Here and Now: Sustainable, Clean, Flexible, GRC 2016 Geothermal Energy Here and Now Sustainable, Clean, Flexible - Geothermal Resources Council 2016 Annual Meeting, 40, 279-286, 2016, Binary cycles are the most common method to extract energy from moderate geothermal resources worldwide. This research investigates and compares the performance of Organic Rankine Cycle (ORC) for binary geothermal power plants from the thermodynamic point of view. A hypothetical ORC cycle which is using 150°C geothermal water as a heat source was considered in this study and its exergy and energy analysis were performed. A parametric study was also performed to understand the effect of ambient temperature and its effect on both energy and exergy efficiencies. The exergy and energy efficiencies, cooling water pump power consumption and also exergy destruction for each component are calculated within different ambient temperature and dead state as well. The results indicated that energy efficiency of the plant varies by 1 and 7% in two different scenarios that were assumed based on different control volume description for the system. Scenario (a) and (b) are based on brine exergy input rate to plant and exergy flow rate decrement across heat exchanger, respectively. Meanwhile, exergetic efficiencies of the cycle face 70%; and 34% increment based on different exergy inflows scenarios. It was concluded that condensers are the most sensitive component to dead state temperature..
40. Nugroho Agung Pambudi, Ryuichi Itoi, Saeid Jalilinasrabady, Puji Sirait, Khasani Jaelani, Preliminary analysis of single flash combined with binary system using thermodynamic assessment
a case study of Dieng geothermal power plant, International Journal of Sustainable Engineering, 10.1080/19397038.2014.915895, 8, 4-5, 258-267, 2015.09, This paper addressed the performance of single flash combined with a binary system that was proposed in the Dieng geothermal power plant by applying thermodynamic assessment methods. A set of mathematical equations from the plant was developed and solved iteratively using engineering equation solver. The results showed that the available exergy of the produced fluid from production wells is 66,204 kW. The performance of an existing single-flash power plant indicated 24,300 kW of net power output. The proposed design of single flash combined with a binary system improves the power output by 17.16% to 27,786 kW. The second law efficiency increases from 36.7% to 41.97% while the first law efficiency increases from 11.62% to 13.61%..
41. Nugroho Agung Pambudi, Ryuichi Itoi, Saeid Jalilinasrabady, Khasani Jaelani, Performance improvement of a single-flash geothermal power plant in Dieng, Indonesia, upon conversion to a double-flash system using thermodynamic analysis, Renewable Energy, 10.1016/j.renene.2015.02.025, 80, 424-431, 2015.08, We investigated proposed design of a double-flash system and compared it to the existing single-flash power plant in Dieng, Indonesia, which uses waste brine from a high pressure separator. The performance of the double-flash system was evaluated using the second law of thermodynamics, and this was based on energy and exergy analyses. The Engineering Equation Solver (EES) was used to solve the relevant mathematical equations.Our results indicate that the double-flash design is interesting for application in Dieng since the power output would increase by 19.97%. Moreover, the precipitation system to avoid silica deposition in the injection well does not have to change much. Therefore, the building costs associated with the new double-flash system would be minimal. The available exergy from the reservoir is 66,204kW based on the enthalpy determined by TFT (Tracer Flow Test) measurements. The single-flash power plant has a net power output of 23,400kW with a second law efficiency of 36.7%. In the double-flash design, components such as a LPS, a second purifier and an HPT would be added to the plant. Furthermore, our calculations indicate that the power plant's output and second law efficiency would increase to 29,155kW and 44.04%, respectively. The waste brine disposed of using this precipitation system would decrease by 8.22% at 5443kW..
42. Younes Noorollahi, Meysam Pourarshad, Saeid Jalilinasrabady, Hossein Yousefi, Numerical simulation of power production from abandoned oil wells in Ahwaz oil field in southern Iran, Geothermics, 10.1016/j.geothermics.2015.01.008, 55, 16-23, 2015.05, Abandoned oil and gas wells can be used as low temperature geothermal resources for heat extraction from geological formations. They can provide valuable potential sources of heat without the extra cost of deep drilling required in traditional geothermal projects. In this study, two oil wells (AZ and DQ) in southern Iran were numerically simulated using a 3D technique for heat extraction. The bottom-hole temperature of wells AZ and DQ were 138.7. °C and 159.8. °C, respectively. Heat transfer between the fluid injected into the well and the surrounding hot rock was simulated. Well casing geometry and an exact thermal gradient for two abandoned oil wells were considered. The simulation results were optimized for parameters such as input and output fluid flow rates and temperatures. The results revealed that, in addition to thermal gradient and input mass flow rate, well casing geometry and the size of injection and extraction pipes were essential to the output heat extraction rate. The small internal diameter of the wells and design of the injection and extraction pipes were limited, resulting in lower mass flow rate and higher power consumption by the injection pump. Total extractable rate of heat from wells AZ-II and DQ-II was 967. kW and 1842. kW, respectively, and net electricity generation using a geothermal binary cycle was 138. kW and 364. kW, respectively..
43. Nugroho Agung Pambudi, Ryuichi Itoi, Rie Yamashiro, Boy Yoseph CSS Syah Alam, Loren Tusara, Saeid Jalilinasrabady, Jaelani Khasani, The behavior of silica in geothermal brine from Dieng geothermal power plant, Indonesia, Geothermics, 10.1016/j.geothermics.2014.12.003, 54, 109-114, 2015.03, Silica scaling in the Dieng geothermal power plant was investigated experimentally. We conducted two kinds of polymerization experiments to examine the behavior of silica in brine along the canals at production wellpads. Acid-treated and untreated brines were sampled along the canal to understand the effects of acidification on silica polymerization and deposition. Chemical analysis of the Dieng brine indicated high silica and salt concentrations. Silica concentrations of acid-treated brine showed that acidification successfully suppresses the deposition of silica along the canal, preventing it from fulfilling its purpose of depositing as much silica as possible. In contrast, significant silica polymerization occurred along the canal when the brine was not acidified. Batch experiments for silica polymerization at constant temperature indicated that both concentrations of total and monomeric silica decrease quickly in early times followed by gradual decrease with time..
44. Younes Noorollahi, Roghayeh Ghasempour, Saeid Jalilinasrabady, A GIS based integration method for geothermal resources exploration and site selection, Energy Exploration and Exploitation, 10.1260/0144-5987.33.2.243, 33, 2, 243-258, 2015.01, A toolbox using a Geographic Information System (GIS) was developed and introduced as a decision-making tool to locate potential geothermal areas. The study aims to introduce step-by-step guidelines and develop a user friendly computer program that can determine promising geothermal areas. Six data layers characterizing the geothermal area are employed in the site selection process. ArcMap was used as a base program to develop the GIS Model for Geothermal Resource Exploration (GM-GRE), which consists of geoprocessing tools and a model builder. Criteria for defining promising areas based on each layer are defined using spatial relationship analysis of currently producing geothermal wells in Akita and Iwate prefectures in northern Japan as proven geothermal resources and evidence layers. Areas with geothermal potential were defined and prioritized using input data layers..
45. Younes Noorollahi, Sara Sokhansefat, Tahmineh Sokhansefat, Kiana Rahmani, Saeid Jalilinasrabady, Biodiesel resources assessment and evaluation of the production capacity from Salicornia plant in Golestan Province, North-East Iran, International Journal of Renewable Energy Research, 5, 3, 847-858, 2015, Biofuel products from halophytic plants are valuable due to their high oil content and growth on non-productive, salt-affected lands. The northern part of Golestan Province has high potential for bio-fuel production from salt-tolerant plants such as Salicornia bigelovii (oilseed halophyte) due to its water and soil properties. In this research, the suitable locations for growingSalicornia plant in Golestan Province were defined based on suitability analysis. By this analysis, the suitable area for cultivation and total amount of producible biodiesel were evaluated. In this regard, the principal parameters were defined and the suitable areas were specified by spatial superposition of these layers, using Geographical Information System (GIS). The Index Overlay model was applied for data combination in suitability analysis. The results showed that the most suitable lands for growing Salicornia, are located in the North-West part of Golestan Province with an area of 2365km2, corresponding to about 12% of the total study area. The total amount of producible biodiesel of this area is estimated to be 201.143 million liters per year..
46. Saeid Jalilinasrabady, Geothermal direct utilization-design and optimization, 39th Geothermal Resources Council Annual Meeting - Geothermal: Always On, GRC 2015 Geothermal Resources Council Annual Meeting, GRC 2015 - Geothermal Always On, 39, 133-144, 2015, The Sabalan geothermal area in northwest of Iran is potentially an important place for tourism in Iran. After realizing the plans for building the first geothermal electric power plant in this region and developing swimming pools, using the geothermal water available in this area, hopefully it will be more attractive for tourists and also provide good sanitation facilities for the local people. According to calculations described in the paper, Gheynarjeh hot spring has been found to be suitable as a heat source for a swimming pool, both with regard to the required temperature and flow rate. The paper also describes the design of a district heating system for Moeil village. The heat load for one sample building was calculated. Comparison of mass flow for a geothermal and fuel-fired system was done, and the influence of radiator size on indoor temperature was analyzed based on a steady-state model. In addition to this, a district heating network was designed and calculations done for it. The simulation results are reasonable and provide a good starting point for a real project..
47. Jane Uwera, Ryuichi Itoi, Saeid Jalilinasrabady, Thirleikur Jóhannesson, Davíd Örn Benediktsson, Design of a cooling system using geothermal energy for storage of agricultural products with emphasis on Irish potatoes in Rwanda, Africa, 39th Geothermal Resources Council Annual Meeting - Geothermal: Always On, GRC 2015 Geothermal Resources Council Annual Meeting, GRC 2015 - Geothermal: Always On, 39, 157-164, 2015, This study focuses on the design of a cooling system for storage of agricultural products. An absorption refrigeration unit which uses a geothermal heat source to drive the absorption cycle in a chilling process, in a 25°C environment with a compartment temperature of 5°C. This system is to provide the cooling to the cold storage with a heat load of 140 kWt. The parameters mainly monitored are COP, heat transfer rates, mass flow of a geothermal fluid and the power required to run the cycle. Thermodynamic analysis of the cycle concluded that the COP of the absorption refrigeration cycle is 0.49, but can go as high as 0.6 when a heat exchanger is used..
48. Nugroho Agung Pambudi, Ryuichi Itoi, Saeid Jalilinasrabady, Khasani Jaelani, Exergy analysis and optimization of Dieng single-Flash geothermal power plant, Energy Conversion and Management, 10.1016/j.enconman.2013.10.073, 78, 405-411, 2014.01, Exergy analysis and optimization of a single-flash geothermal power plant are conducted by developing a mathematical model that is applied to the Dieng geothermal power plant in Indonesia. Calculations are conducted by using the Engineering Equation Solver (EES) code using methods based on the laws of thermodynamics. The exergy flow and efficiency are computed at several plant components, including the separator, turbine, condenser, and for the whole power plant. The exergy of the geothermal fluid that is discharged from the production wells is estimated to be 59.52 MW. This amount of fluid produces 21.71 MW of electricity from the power plant overall, with second law efficiency to be 36.48%. There is a considerable amount of waste brine, amounting to 17.98% (10.70 MW) of the total available exergy, which is disposed of in the plant's reservoir. The optimization of the plant is carried out by adjusting the separator pressure. The results show that a slight increase of 20 kW in the output power can be attained by lowering the separator pressure to 9 bar from 10 bar. The Grassmann diagram shows the exergy losses at each component in the power plant. The turbine and separator losses are 7.51 MW (12.62%) and 8.04 MW (13.5%), respectively, while the cooling tower has an exergy loss of 2.62 MW (4.40%). The total condenser loss is 5.8 MW (9.75%)..
49. Saeid Jalilinasrabady, Ryuichi Itoi, Yuji Ohya, Hybrid geothermal and wind power generation, Geothermal Resources Council Annual Meeting: A Global Resource, from Larderello to Las Vegas, GRC 2013 Geothermal Resources Council Annual Meeting, GRC 2013 A Global Resource, from Larderello to Las Vegas, 37, 727-731, 2013.12, A novel idea of hybrid power generation system has been proposed that can be characterized as a simple and renewable method to achieve sustainable utilization of renewable resources. The new hybrid system utilizes a solar chimney to produce electricity with a windmill. Geothermal heat will be used as a heat source to achieve desirable air speed inside the chimney. Calculations suggest the idea may be competitive with other renewable energy sources. Further studies are necessary to achieve more realistic results to start an actual project..
50. Saeid Jalilinasrabady, Ryuichi Itoi, Classification of geothermal energy resources in Japan applying exergy concept, International Journal of Energy Research, 10.1002/er.3002, 37, 14, 1842-1850, 2013.11, Higher demand for energy consumption and importance of environmental issues has encouraged researchers and policy makers to consider renewable energies more seriously. Geothermal resources are a green energy source that can make a considerable contribution in some countries. Japan has the third ranking geothermal energy potential, and its geothermal electricity production is currently eighth in the world. Since the nature of geothermal resources dictates its method of utilization, it is important to categorize available resources. There is no consensus on classification of geothermal resources. Most scientists, from geologist to engineers, agree on the term temperature. However, temperature or enthalpy alone cannot describe the nature of fluids; they can have same temperature with different phases, such as saturated water or saturated steam. Using exergy for resource classification benefits their comparison, according to their ability to do work. In this paper, exergetic classification of geothermal resources was applied to 18 under-operating geothermal power plants in Japan. Six geothermal fields have high exergy resources according to their SExI values in excess of 0.5. The remaining geothermal fields in Japan are classified in the medium resources zone. Classification results can be used by decision makers as a reference for future geothermal development..
51. Saeid Jalilinasrabady, Halldor Palsson, Gudrun Saevarsdottir, Ryuichi Itoi, Pall Valdimarsson, Experimental and CFD simulation of heat efficiency improvement ingeothermal spas, Energy, 10.1016/, 56, 124-134, 2013.07, Hot spas and jacuzzis are popular in Iceland due to the abundance of reasonably prized geothermal heat available. However the water from the DH (district heating) system is too warm to be admitted directly into the spa. For safety reasons the water is mixed with cold water, from 75. °C down to 50. °C, which leads to wasting a large quantity of heat. Therefore a design was suggested that enables the feeding of geothermal water directly into the pot, omitting the step of mixing it with cold water. The idea is to employ an open heat exchanger that transfers much heat from the geothermal water to the bulk water in the spa, before letting it mix with the spa water. A case study was done for one particular spa. Heat load was calculated and measured when the spa was in use, and when it was unused. A design is suggested employing a circular double-plate which is to be placed at bottom of pot. This unit will function as an open heat exchanger feeding DH water into the pot. Free convection takes place at the up side of the upper plate and forced convection below the upper plate. Heat-transfer coefficient for both was calculated. Temperature field in the pool before and after implementation of the open heat exchanger was measured at different points using thermocouples. The measured temperatures were compared to thermal and fluid-dynamic simulation of the temperature and flow fields obtaining good accordance. Results are reasonable and promising for a good design that may considerably reduce the energy expenses for a continuously heated geothermal spa. More detailed measurements were made on the upper plate of the heat exchanger and detailed simulation of the heat exchanger itself was then used to obtain a value for the heat-transfer coefficient for the upper plate to the surrounding water. This information was used to make an improved design for the open plate heat exchanger, stating that a diameter of 63. cm and a thickness of 1.5. cm were suggested as final design. Due to economy consideration the recovery time of the implementing of suggested heat exchanger is estimated to 8 months in studied case..
52. Saeid Jalilinasrabady, Ryuichi Itoi, Pall Valdimarsson, Gudrun Saevarsdottir, Hikari Fujii, Flash cycle optimization of Sabalan geothermal power plant employing exergy concept, Geothermics, 10.1016/j.geothermics.2012.02.003, 43, 75-82, 2012.07, The Sabalan geothermal field in northwest Iran is currently under development. A single flash cycle has been selected for power generation. The analysis of the proposed design shows the maximum net power output of the plant can reach 31. MW if the pressures of the separator and condenser are 5.5 and 0.3. bar, respectively. To achieve optimum energy utilization, a double flash cycle was also evaluated for power generation. The results indicate the maximum net power output of the plant reaches 49.7. MW if the pressures for the high- and low-pressure steps and condenser are 7.5, 1.1, and 0.1. bar, respectively. Mathematical models for energy and exergy flows were developed and implemented in Engineering Equation Solver (EES) software. In the single flash cycle, the energy and exergy of the waste water were calculated as 54.8% and 41.4% of the total available energy and exergy, respectively. The energy and exergy of waste water were respectively calculated as 19.88% and 15.3% of the total available energy and exergy, in the double flash cycle. The parts of the system with largest exergy destruction in both cycles were compared and the overall exergy and energy efficiencies for the power plant were calculated. The total exergy available from production wells at Sabalan was calculated to be 111. MW for the single flash system, and 114. MW for the double flash system. The results of the analysis suggest a double flash cycle system for the Sabalan power plant..
53. Saeid Jalilinasrabady, Ryuichi Itoi, Flash cycle and binary geothermal power plant optimization, Geothermal Resources Council Annual Meeting 2012 - Geothermal: Reliable, Renewable, Global, GRC 2012 Geothermal Resources Council Annual Meeting 2012, GRC 2012 - Geothermal: Reliable, Renewable, Global, 36 2, 1079-1084, 2012, This research was conducted to provide a guide or reference that could quickly and easily be used to determine the optimum power output and choose the most efficient energy conversion technology. Three energy conversion models were analyzed and simulated. A single flash plant was chosen as the main energy conversion system due to its simplicity and reliability. Two other energy conversion systems were considered as the bottoming unit of the single flash, double flash and Organic Rankine Cycle (ORC). Also their combination with district heating system was investigated. Engineering equation solver software (EES) was used for modeling and simulation. Comparison of power output for three cycles show that ORC cycle is more efficient from the view of power output. Also it has the highest thermal efficiency when district heating is added for heat recovery of waste heat from plant..
54. Hendra Riogilang, Ryuichi Itoi, Toshiaki Tanaka, Saeid Jalilinasrabady, Natural state model of the Kotamobagu geothermal system, North Sulawesi, Indonesia, Geothermal Resources Council Annual Meeting 2012 - Geothermal: Reliable, Renewable, Global, GRC 2012 Geothermal Resources Council Annual Meeting 2012, GRC 2012 - Geothermal: Reliable, Renewable, Global, 36 2, 1299-1304, 2012, A three-dimensional numerical reservoir modeling of the Kotamobagu hydrothermal system was carried out. A natural state model of Kotamobagu was obtained by conducting simulations by changing parameter values of permeability, heat and mass recharges. The results of simulation were calibrated to temperature data from hot spring of Liberia and Bongkudai villages. The developed model confirmed that mass flows upward from the bottom layer to the surface, then travels laterally. The dominant mass flows through faults running northeast and to southwest. The mass from the bottom of Mt. Muayat flows to the southwest through the andesitic lava and the pumice tuff layers. Further, at the surface of Liberia and Bongkudai area, 3kg/s of mass is being discharged to the hot spring, the portion of mass flows through the fault to the southwest and continues further to the west. In the southwest area, mainly in Bakan, there is no mass discharge corresponding to related modeling blocks. Simulation results implies that the source of heat and mass discharge at the Bakan hot spring is not derived from Mt. Muayat, but from some source below sedimentary formation..
55. Saeid Jalilinasrabady, Ryuichi Itoi, Hiroki Gotoh, Rie Yamashiro, Exergetic optimization of proposed Takigami binary geothermal power plant, Oita, Japan, Geothermal Resources Council Annual Meeting 2011, Geothermal 2011 Geothermal Resources Council Annual Meeting 2011, Geothermal 2011, 35 2, 1305-1311, 2011.12, The single flash Takigami Geothermal Power Plant is located in the southwestern part of Oita prefecture, Kyushu Island, Japan, with installed capacity of 27.5 MW. Energy and exergy of waste brine from a single flash system were calculated as 45.71%) and 37.64% of the total available energy and exergy of the produced fluid, respectively. The separated brine could be used as a heat source for a combined power production and direct use applications. For a feasibility study of waste heat utilization, a binary plant was selected for power generation in a combined system with the single flash plant. The net power output of the binary plant was calculated to be 8,660 kW. Mathematical models for energy and exergy flows were developed and implemented in Engineering Equation Solver software. The largest exergy destruction for the waste brine occurred at the condenser and evaporator with 16.6% and 30.5%) of total available exergy destroyed, respectively. The overall exergy and energy efficiencies for the binary plant were 31.15%) and 4.67%, respectively. A Grassmann diagram of the overall exergy flow illustrates the overall exergy flow of the process. Exergy analysis is a helpful tool for analyzing geothermal plants from the viewpoint of optimum use of produced energy..
56. Saeid Jalilinasrabady, Ryuichi Itoi, Pall Valdimarsson, Hikari Fujii, Toshiaki Tanaka, Energy and Exergy Analysis of Sabalan Binary Geothermal Power Plant, journal of the geothermal research society of japan, 10.11367/grsj.33.113, 33, 3, 113-121, 2011.07, The Sabalan geothermal field in northwest Iran is currently under development. Energy and exergy of waste brine from a designed single flash system were calculated as 54.8 % and 41.4 % of the total available energy and exergy of the produced fluid, respectively. The separated brine could be used as a heat source for a combined power production and district heating system. For a feasibility study of waste heat utilization, a binary plant was selected for power generation in a combined system with the single flash plant. The net power output of the binary plant was calculated to be 17,151 kW. Mathematical models for energy and exergy flows were developed and implemented in Engineering Equation Solver software. The largest exergy destruction for the waste brine occurred at the condenser and evaporator with 12.1 % and 33.4 % of total available exergy destroyed, respectively. The overall exergy and energy efficiencies for the binary plant were 34.4 % and 6.25 %, respectively. A Grassmann diagram of the overall exergy flow illustrates the overall exergy flow of the process. Exergy analysis is a helpful tool for analyzing geothermal plants from the viewpoint of optimum use of produced energy..
57. Saeid Jalilinasrabady, Ryuichi Itoi, Hiroki Gotoh, Hiroyuki Kamenosono, Energy and exergy analysis of Takigami Geothermal Power Plant, Oita, Japan, Geothermal Resources Council Annual Meeting 2010, Geothermal 2010 Geothermal Resources Council Annual Meeting 2010, Geothermal 2010, 34 2, 966-971, 2010.10, The single flash Takigami Geothermal Power Plant is located in the southwestern part of Oita prefecture, Kyushu Island, Japan, with installed capacity of 25 MW. Mathematical models for energy and exergy flows were developed and implemented in the Engineering Equation Solver (EES) software. The energy and exergy rates of the waste brine have been calculated. The parts of the system with largest exergy destruction were defined. The overall exergy and energy efficiency for whole system were obtained. Grassmann presentation of the overall exergy flow was illustrated. Exergy analysis was found to be a helpful and important tool for analyzing the geothermal plant from the view point of optimum usage of produced energy..