Geothermal Source Temperature Research Articles

Feasibility of optimum energy use and cost analyses by applying artificial intelligence and genetic optimization methods in geothermal and solar energy-assisted multigeneration systems

This study evaluates the potential for optimizing energy utilization and cost analysis in geothermal and solar energy-supported multigeneration systems using artificial intelligence (AI) and genetic algorithm (GA) optimization methods. Integrating renewable energy sources aims to promote sustainable energy solutions focusing on efficiency and cost-effectiveness. A cogeneration system that leverages geothermal and solar energy for electricity generation and space cooling is analyzed. The model incorporates an organic Rankine cycle (ORC) for power generation and a geothermal-solar absorption cooling cycle for space cooling, developed using Artificial Neural Networks (ANN) and optimized through thermoeconomic methods. Thermodynamic and thermoeconomic analyses guide the optimization process using an ANN-based GA method. The system, with parameters such as a 130 °C geothermal source temperature, an 85 kg/s mass flow rate, and a 600 W/m2 monthly average solar radiation intensity in Afyonkarahisar, achieves overall energy and exergy efficiencies of 19.5 % and 43.5 %, respectively. Optimization via the GA method significantly improves performance, increasing net power output from 2240 kW to 2760 kW and cooling capacity from 2720 kW to 3061 kW. Additionally, the cost of electricity decreases by 12.1 %, from 0.0165 $/kWh to 0.0145 $/kWh, while the cooling cost is reduced by 41.9 %, from 0.0745 $/kWh to 0.0525 $/kWh.

Enhancing green hydrogen production via improvement of an integrated double flash geothermal cycle; Multi-criteria optimization and exergo-environmental evaluation

The environmental advantages of hydrogen as a clean energy carrier are more prominent when it is produced utilizing renewable resources. In this regard, a novel geothermal energy driven electricity generation system integrated to hydrogen production plant is developed and investigated in this research. In the developed plant, a PEM electrolyzer is employed for hydrogen generation such that its required electricity is provided by an improved double-flash geothermal cycle. A self-superheater is applied for superheating the vapor at the steam turbine inlet using the geothermal resource to enhance the hydrogen production capacity. To evaluate feasibility of such superheating process and to examine its effects on hydrogen production, thermodynamic models are developed based on first and second laws. Also, environmental considerations are considered in evaluation of the proposed plant performance based on exergo-environmental indices. The influences of first and second flashing pressure, geothermal source temperature and current density of water electrolyzer on energy and exergy efficiency, hydrogen production rate, and environmental damage index are investigated. After carrying out a parametric study, the optimum operation point of the plant is determined via a two-objective optimization based on the hydrogen rate and environmental damage index (EDI). It is found that, under optimum operation, the system can produce 25.48 kg/h of hydrogen, while its environmental damage index is calculated to be as 0.00645.

Geothermal Power Generation: Harnessing Electrical Energy Through The Organic Rankine Cycle (ORC) System

The research employs a thermodynamic simulation method using an Engineering Equation Solver (EES), relying on theoretical calculations. This method is integrated into a geothermal power plant, precisely focusing on geothermal source temperatures of approximately 95ºC. The investigation centers on the heat transfer process within a high-temperature heat transfer fluid from geothermal sources, conveying stored heat to the Organic Rankine Cycle (ORC) evaporator. Three specific working fluids, R134a, R11, and R22, examine working fluid selection for ORC at 95ºC. The results highlight the R11 organic fluid as an optimal compromise, excelling in two crucial criteria. Firstly, R11 exhibits the highest net mechanical power, = 34.81 kW compared to alternative fluids. Secondly, it boasts the best energetic efficiency of the cycle, registering = 16.01%, outperforming both R134a ( = 13.17%) and R22 ( = 12.64%). In summary, this study conducts a focused analysis of the energy aspects of an Organic Rankine Cycle (ORC) for electricity production using geothermal sources and organic fluids. Operating at a geothermal source temperature of 95ºC with a water flow rate of 80 lt/s and environmental conditions at 20ºC, the parametric study emphasizes the superiority of the R11 organic fluid. R11 emerges as the optimal choice, demonstrating the highest net mechanical power and superior energetic efficiency compared to alternative fluids, thereby contributing valuable insights to advancing sustainable and efficient energy technologies.

An innovative study on a geothermal based multigeneration plant with transcritical CO2 cycle: Thermodynamic evaluation and multi-objective optimization

Renewable energy-sourced integrated plants are among the novel and interesting technologies for production of the clean and effective beneficial multiple commodities. Also, these technologies are one of the main motivations for overcoming environmental troubles. The newly designed geothermal-based multigeneration plant deals with clean and sustainable power, hydrogen, cooling, and heating generation and then comprehensive thermodynamic and economic analyses. This system is driven by a geothermal source that includes a transcritical CO2 based Rankine cycle, an ejector cooling cycle, a hydrogen generation and compression unit, and a domestic hot water preparation unit. Here, a comprehensive mathematical modeling is discussed that are energy and exergy efficiency methods along with economic cost evaluation. Furthermore, to define the optimal working conditions, a multiobjective optimization method is fulfilled based on the relationship between the developed multigeneration system's cost and exergy efficiency. Additionally, a comprehensive parametric assessment is implemented to describe how effects of various indicators on the developed model’s efficiency. In outlook of these outcomes, it is crystal clear that the quantity of clean power and hydrogen generation rate is 1283 kW and 0.009374 kgs−1, respectively. The energy and exergy efficiencies of the developed MG cycle are figured as 27.60% and 22.56%, at 152 ℃ geothermal source temperature. the optimal plant total cost rate is computed as 80.48 $h−1. Finally, it is concluded that this proposed system's performance and cost rates are compatible and applicable.

Case study: Repowering of ORC system by means of experimental test bench with supercritical carbon dioxide, proposal, and field experience improvements

Although organic Rankine cycles (ORCs) have cornered the small-scale energy harvesting market, the generation capacities produced by sCO2 cycles far exceed those of ORCs, reaching higher powers and efficiencies. This paper analyzes the results of the field tests performed in 2022 at the Grupo Dragón, Nayarit, Mexico, facilities, in which the objective was to validate the operation of the ORC IDEA-10 system with a capacity of up to 10 kWe. The thermodynamic states reached during the test time lapses in which there was full operational stability and with direct loads are analyzed. The results obtained together with proposals for improvement led to compare the performance of ORCs with sCO2 systems for low temperature geothermal sources. The efficiencies of simple sCO2 cycles (5.32%) turned out to be lower than that of ORC at the same temperatures (9.7%), however, the efficiency of the sCO2 cycle improved notably in a regenerative configuration, given the properties of CO2 near its critical point, reaching efficiencies above 25% even at low temperatures compared to conventional ORCs with efficiencies below 10%. Finally, the basis for the implementation of sCO2 in low enthalpy geothermal applications was established, designing an experimental circuit with results obtained in the literature.

Case study: Design of an absorption refrigeration system for milk preservation in Jalisco, Mexico

This article presents a case study focused on designing a refrigeration system for milk storage in a town of Jalisco, Mexico. An absorption refrigeration unit is proposed, activated with a geothermal heat source from an existing well. An economic analysis of the proposal and its comparison with a conventional system and a solar system is presented. The proposed system must provide refrigeration to the warehouse (cold room) with a cooling load of 5 kW, with a geothermal heat source temperature of 80 °C for the single effect system and 163 °C for the double effect system. For the design of the warehouse, the thermal loads were obtained through ceilings and walls, by lighting, infiltration, and by occupation, through the EnergyPlus software. The results show values of monthly thermal loads ranging between 0.94 and 1.1 kW. The single-effect system achieved a COP of 0.85 costing approximately $13,083, while the double-effect system reached a COP of 1.38 with a cost of $18,144.

An innovative compressed air energy storage (CAES) using hydrogen energy integrated with geothermal and solar energy technologies: A comprehensive techno-economic analysis - different climate areas- using artificial intelligent (AI)

The present study evaluates the optimal design of a renewable system based on solar and geothermal energy for power generation and cooling based on a solar cycle with thermal energy storage and an electrolyzer to produce hydrogen fuel for the combustion chamber. The subsystems include solar collectors, gas turbines, an electrolyzer, an absorption chiller, and compressed air energy storage. The solar collector surface area, geothermal source temperature, steam turbine input pressure, and evaporator input temperature were found to be major determinants. The economic analysis of the system showed that the solar subsystem, steam Rankine cycle, and compressed air energy storage accounted for the largest portions of the cost rate. The exergy analysis of the system demonstrated that the solar subsystem and SRC had the highest contributions to total exergy destruction. A comparative case study was conducted on Isfahan, Bandar Abbas, Mashhad, Semnan, and Zanjan in Iran to evaluate the performance of the proposed system at different ambient temperatures and irradiance levels during the year. To optimize the system and find the optimal objective functions, the NSGA-II algorithm was employed. The contradictory objective functions of the system included exergy efficiency maximization and cost rate minimization. The optimal Exergy round trip efficiency and cost rate were found to be 29.25% and 714.25 ($/h), respectively.

Optimization design and analysis of a novel total flow and Kalina cycle coupled system driven on low-medium temperature geothermal source with two-phase mixture

A novel total flow and Kalina cycle coupled system has been proposed to utilize the geothermal energy with a certain dryness. To confirm the feasibility and advantages of the proposed system, Particle Swarm Optimization is introduced to optimization design the operating conditions of the system. At design conditions, maximum net output power which is as the single-subjective optimized goal reaches 781.88 kW and the corresponding thermal efficiency and exergy efficiency achieves 12.96 % and 48.54 %, respectively. Meanwhile, thermodynamic properties in each state point of the system are calculated and compared with those of the basic Kalina cycle by selecting the evaporating pressure and the concentration of basic ammonia water as variables. The maximum net output power of the novel system is 111.92 kW more than that of the basic Kalina cycle, while the thermal and exergy efficiencies are also 1.07 % and 6.95 % higher at their respective design condition. In terms of exergy destruction, the evaporator and the condenser occupy the most parts of the system total exergy destruction. Comprehensively analyzing the system performance from the aspects of thermodynamic first and second laws, the proposed novel system has an excellent performance and a great potential to apply in the industrial field.

Comparison of Thermodynamic Performances in Three Geothermal Power Plants Using Flash Steam

Abstract Three geothermal systems, including single-flash, double-flash, and double-flash connected turbine flash geothermal power plants, are compared in terms of electrical power production and exergy efficiency. In the double-flash connected turbine (double-T) geothermal electrical power production systems, the outlet stream from the first steam turbine is recovered in the mixing chamber and combined with the vapor product of the second separator. The thermodynamic model for the single-flash, double-flash, and double-T geothermal systems is developed using energy and exergy balances for each component of the systems. From the thermodynamic model, the optimum flash chambers pressures, at which the electrical power production is a maximum, can be determined. It is found that, for an input geothermal source temperature of 230 °C and an input geothermal water mass flowrate of 230 kg/s, the optimum pressures for the first flash chamber are 300 kPa, 350 kPa, and 350 kPa for the single-flash, double-flash, and double-T geothermal systems, respectively. The electrical power produced in these systems at their corresponding optimum flashing pressures, respectively, are 16,000 kW, 19,500 kW, and 20,600 kW. Also, for the single-flash, double-flash, and double-T geothermal systems, the exergy efficiency at the optimum flash chamber pressures are found to be 44.2%, 47.1%, and 48.5%, respectively.

Effect of layout and working fluid on heat transfer of polymeric shell and tube heat exchangers for small size geothermal ORC via 1-D numerical analysis

The geothermal energy is widely diffused in high size thermoelectric application by using high temperature sources. A high share of geothermal reservoirs is available worldwide in low-medium temperature and it is exploited only for thermal scopes. The use of low-medium enthalpy geothermal sources could be improved by considering the installation of small size power plant in fragmentary and poorly exploited geothermal sites providing power only or heat and power by using Organic Ranking Cycles technology. In order to reduce the cost of these typologies of geothermal power plant a strategy is here proposed to make them commercially attractive. In addition to drilling cost, a further element such as the corrosion issue strongly affects the economic analysis leading to the use of expensive components realized with high resistance materials that need to be frequently cleaned and/or replaced. The exploitation of low-medium temperature geothermal sources could be enhanced by using innovate cheaper materials for heat exchanger allowing the direct interaction between working fluid and geothermal brine, appropriately treated, taken by the aquifer. The present work aims to analyse the use of a polymer-based evaporator in a 10 kWel Organic Rankine Cycle system to overcome the fouling problem due to geothermal fluid. A detailed analysis with two different layouts for a shell and tube heat exchanger, by considering the combination of five different working fluids, by comparing three polymers with two commonly used metals, has been conducted. This analysis has been carried out with a one-dimensional mathematical approach including the evaluation of heat exchange coefficients and pressure drops by using the correlation available in the scientific literature for each possible combination of fluid-material-layout. The outcomes provide the energy and economic analysis for the shell and tube heat exchanger considering the design characteristic of modelled ORC system. The results have demonstrated that the higher performance will be obtained if the working fluid is in the tubes side. The best combination of fluid, layout and polymer leads to a cost saving of evaporator of 73% with respect to titanium on the basis of the same life cycle time.

Assessment of a high-performance geothermal-based multigeneration system for production of power, cooling, and hydrogen: Thermodynamic and exergoeconomic evaluation

The novel multi-generation system is developed to produce power, cooling, and hydrogen. The present work is suggested to employ the geothermal energy to start a Kalina cycle and then with regard to the high temperature of the saturated liquid leaving the Kalina cycle separator, the absorption refrigeration system is employed for providing cooling as a subsystem. Also, an electrolyzer and the power production capacity of the cycle have been utilized to produce hydrogen. The proposed system is evaluated thermodynamically and exergoeconomically, and a parametric study was performed for the following parameters: geothermal heat source temperature (THS,in), the temperature difference in vapor generator 1 (ΔTPP,vg1), the pressure of vapor generator 1 (Pvg1), condenser temperature (Tcon), evaporator temperature (Teva) and ammonia concentration (YB). The governing equations are coded in the EES software. In the base case, the results display that the proposed system is capable of producing 258.6 kW of cooling, and in this case, the thermal and exergy efficiencies and the unit cost of multigeneration are 22.28%, 21.37% and 29.29 $/GJ, respectively. Also, increasing the evaporator temperature does not have a significant effect on power production capacity. Moreover, condenser 1 has the most exergy destruction rate of 65.03 kW.

A Micro-trigeneration Geothermal Plant for a Smart Energy Community: The Case Study of a Residential District in Ischia

Improvements for islands sustainability subjected to strong anthropogenic pressures could be obtained by innovative solutions for energy supply by using local energy renewable sources. This paper analyses the possible benefits of a geothermal energy community, consisting of residential users, located in Ischia, an island of Naples in South of Italy. The proposed system is mainly based on an Organic Rankine Cycle plant interacting with a medium temperature geothermal source. This system satisfies both community’s pure electric load and electricity requests of the electric-driven heat pumps for space conditioning and domestic hot water demands. The entire system and residential users were modelled and dynamically simulated by considering hourly electric, thermal/cooling and domestic hot water loads variation during three reference days for winter, summer and intermediate season. The proposed plant was compared to a traditional system in which the electricity to meet the total community’s electric loads, is taken from the national power grid. The results highlight that the use of proposed system instead of traditional one allows to avoid 29.9 tons per year of CO2 emissions. Furthermore, this proposed system ensures the island-operation of community exploiting local renewable energy source and improving the energy independency.

Geothermal energy for wastewater and sludge treatment: An exergoeconomic analysis

The highest economic and environmental costs of wastewater treatment plants are related to waste disposal, which is mainly sludge disposal, and energy supply. Such challenges are even more critical in islands, where there are many environmental, landscape, and geographical constraints that make the use of conventional technologies difficult. For this reason, a geothermal energy system for wastewater and sludge treatment, and power production is proposed. Such a system is assessed through an exergoeconomic analysis, performed in Engineering Equation Solver environment, that allows determining the exergoeconomic costs of geo-fluid, electricity production, and sludge drying. The sensitivity analyses, carried out to assess the effect of several design parameters, have highlighted that the geothermal source temperature significantly affects the system operation and consequently the exergoeconomic costs, which range 77–95 c€/kWhex for sludge treatment and between 4.8 and 6.6c€/kWhex for electricity production. Finally, multivariate optimization has been carried out to find the conditions that minimize the exergoeconomic costs of the system. The total hourly exergoeconomic cost of the system products, namely sludge and electricity, is minimized when the geothermal source temperature is equal to 110 °C and the 58.91% of the desiccant flow is recycled.Overall, this study outlines that an exergy-based economic analysis is fundamental to assess the economic viability of innovative integrated solutions based on renewables.

Jeotermal Enerji Kaynaklı Multi-Jenerasyon Enerji Sisteminin Termodinamik ve Performans Değerlendirmesi

In this study, a new integrated geothermal energy based plant is proposed for multigeneration purposes such as hydrogen, electricity, hot water, drying, cooling and heating. Therefore, this proposed integrated system is consisted of proton exchange membrane electrolyzer, hydrogen compression unit, organic Rankine cycles, single effect absorption cooling cycle, hot water storage tank and a drying unit. Thermodynamic analyses including of energy and exergy analyses have been performed for general evaluation of the proposed system. Energy and exergy efficiencies of whole plant are found as 37.65% and 39.26%, respectively. In addition to these analyses, parametric analyses have been carried out to see how some variables affect system performance and useful product generation. For this reason, the impacts of dead state temperature, geothermal mass flow rate, geothermal source temperature and pinch point temperature of heat exchanger 1 are investigated. Any increase in dead state temperature, geothermal mass flow rate and geothermal source temperature has positive impact on system performance and useful product generation. Increase in pinch point temperature of heat exchanger 1 decreases the system performance. Hydrogen production rate reaches maximum point (0.0024 kg/s) when geothermal mass flow rate is 8.125 kg/s or when geothermal working fluid temperature is 168 °C for this paper.

Application of CCHPs in a centralized domestic heating, cooling and power network—Thermodynamic and economic implications

The main objective of the present study is to utilize the waste heat and low-medium temperature geothermal heat sources in a centralized domestic heating, cooling and electricity network. Both geothermal and waste heat (from cement industry) are utilized to run domestic-scale combined cooling, heating and power (CCHP) units to meet the thermal and electrical demands of a residential area as the case study. Energy and exergy principles are applied to the designed CCHPs and the employed components, while exergoeconomic analysis is developed to show the economic feasibility of the proposed distributed energy systems. It is observed that the designed CCHPs not only meet the local energy demand in a sustainable way, but also deliver surplus thermal and electrical energy to the main grids. The thermodynamic analysis shows that under the base condition, the geothermal and waste heat driven CCHPs operate with sustainability index of 1.985 and 2.747, respectively. The economic evaluations demonstrated that, by using the proposed local CCHPs instead of the main grids to supply energy demand of the case study, it is possible to gain a benefit of 15687 € per year. This results in a lower energy payment of the end-users.

Experimental and Techno-Economic Analysis of Solar-Geothermal Organic Rankine Cycle Technology for Power Generation in Nepal

The current research study focuses on the feasibility of stand-alone hybrid solar-geothermal organic Rankine cycle (ORC) technology for power generation from hot springs of Bhurung Tatopani, Myagdi, Nepal. For the study, the temperature of the hot spring was measured on the particular site of the heat source of the hot spring. The measured temperature could be used for operating the ORC system. Temperature of hot spring can also further be increased by adopting the solar collector for rising the temperature. This hybrid type of the system can have a high-temperature heat source which could power more energy from ORC technology. There are various types of organic working fluids available on the market, but R134a and R245fa are environmentally friendly and have low global warming potential candidates. The thermodynamic models have been developed for predicting the performance analysis of the system. The input parameter for the model is the temperature which was measured experimentally. The maximum temperature of the hot spring was found to be 69.7°C. Expander power output, thermal efficiency, heat of evaporation, solar collector area, and hybrid solar ORC system power output and efficiency are the outputs from the developed model. From the simulation, it was found that 1 kg/s of working fluid could produce 17.5 kW and 22.5 kW power output for R134a and R245fa, respectively, when the geothermal source temperature was around 70°C. Later when the hot spring was heated with a solar collector, the power output produced were 25 kW and 30 kW for R134a and R245fa, respectively, when the heat source was 99°C. The study also further determines the cost of electricity generation for the system with working fluids R134a and R245fa to be $0.17/kWh and $0.14/kWh, respectively. The levelised cost of the electricity (LCOE) was $0.38/kWh in order to be highly feasible investment. The payback period for such hybrid system was found to have 7.5 years and 10.5 years for R245fa and R134a, respectively.

Exergoeconomic comparison and optimization of organic Rankine cycle, trilateral Rankine cycle and transcritical carbon dioxide cycle for heat recovery of low-temperature geothermal water

Depleting fossil fuel resources and the horrible environmental impacts due to burning fossil fuels emphasize the importance of using renewable energy resources such as geothermal and solar energies. This paper compares performance of CO2 transcritical cycle, organic Rankine cycle, and trilateral Rankine cycle using a low-temperature geothermal heat source. Thermodynamic analysis, exergetic analysis, economic analysis, and exergoeconomic analysis are applied for each of the aforementioned cycles. In addition, a sensitivity analysis is performed on the system, and the effects of geothermal heat source temperature, evaporator pinch point temperature, and turbine inlet pressure on the cycle's performance are evaluated. Finally, the systems are optimized in order to minimize product cost ratio and maximize exergetic efficiency by using the genetic algorithm. Results indicate that the maximum thermal efficiency is approximately 13.03% which belongs to organic Rankine cycle with R123 as working fluid. CO2 cycle has the maximum exergetic efficiency, equals to 46.13%. The minimum product cost ratio refers to the organic Rankine cycle with R245fa as working fluid. Moreover, sensitivity analysis shows that increasing geothermal heat source temperature results in higher output power, product cost ratio, and exergy destruction ratio in all cycles.

Thermodynamic analysis of a combined cycle for cold storage and power generation using geothermal heat source

In the present study, an ammonia-water based combined refrigeration/power cycle, proposed previously, is assessed for the utilization of geothermal potential for variable refrigeration and power load. The work mainly focuses on the thermodynamic feasibility of usage of geothermal source for apple storage and power output at Manikaran, a small town in the Indian state of Himachal Pradesh in Himalayan region. Optimization of second law efficiency was done using a combined genetic and gradient based algorithm, for varying ambient conditions and refrigeration load requirements, considering the potential of geothermal heat source available in the area. The system demonstrates the advantage of variable refrigeration and power output ratio that makes the full utilization of a low temperature geothermal heat source all through the year.

Cryogenic energy storage powered by geothermal energy

Geothermal energy is one of the promising alternatives of power generation suitable for energy storage applications for load shifting operations. Cryogenic energy storage (CES) is an attractive option for energy storage driven by geothermal power. In this study, thermodynamic assessment of a cryogenic energy storage unit integrated to a single-flash geothermal power plant is performed and the effect of geothermal source temperature on the system performance is investigated. Initially, a resource that can supply geothermal water at 180 °C at a rate of 100 kg/s is considered. Power generated from the geothermal plant during off-peak hours is used to produce and store liquefied air. This liquefied air is used to generate power during peak hours using the heat of geothermal water. Our analysis indicates that the liquefaction unit consumes 4304 kW power in order to liquefy air for a 6-h charging period. In the discharge mode, the CES unit can produce a net power output of 12,049 kW for a 1-h operation. The flashing pressure is optimized at 255 kPa for which the total power output is 16,100 kW. The round-trip efficiency of the CES unit is determined to be 46.7% while the overall efficiency of the integrated system is 24.4%.

Thermodynamic Analysis of a Rankine Cycle Powered Refrigeration System Using Mid-Low Temperature Geothermal Sources

To efficiently utilize mid-ow temperature geothermal sources, an organic Rankine cycle-vapor compression refrigeration (ORC/VCR) system was employed and a thermodynamic model was developed. Six working fluids of R290, R600, R600a, R601, R601a and R1270 were analyzed and evaluated in order to identify suitable working fluids which may yield high system efficiencies.,and system design and influencing factors were researched with the overall COP and working fluid mass flow rate of per kW cooling capacity as key performance indicators.The results show that R601 is the best working fluid for the ORC/VCR system as the geothermal water temperature is between 60 to 90 °C, When the geothermal water temperature reaches 90 °C and the other input parameters are in typical values, the overall COP of the R601 case reaches 0.48.