Binary Geothermal Power Plant Research Articles

Performance analysis of the Chena binary geothermal power plant

In this paper, the IPSEpro model of the Chena Geothermal ORC Power Plant had been developed and validated using the real data. The validated model was used to investigate the effect of variation in the geothermal source temperature on plant performance. The analysis showed that the variation of the geothermal source temperature affects the plant behaviour. Increase in the geothermal source temperature above the design point increases the working fluid flowrate, decreases the working fluid degree of superheat at the inlet of the turbine (evaporator exit), increases the plant net power output and reduces the efficiency while decrease in the geothermal source temperature lower than the design point increases the degree of superheat up to a certain maximum beyond which it starts to reduce. It also causes a decrease in the net power output and an increase in the plant efficiency.

Performance optimisation of the combined single flash binary geothermal power plant

In this paper, the optimal operating conditions of a hypothetical combined single flash-binary geothermal power plant are investigated and performance analyses are performed based on Aydin-Germencik field in Turkey. The relationship between flashing pressure, turbine inlet pressure of the binary cycle and total heat transfer area of the heat exchanger are determined for maximum power output of the combined power plant. According to the results, the optimal flashing pressure of the flash cycle and the optimal inlet pressure of the working fluid to binary cycle's turbine were found to be 500 kPa and 3620 kPa, respectively. In these pressures, the total power output of the combined power plant and the total heat transfer area of the heat exchanger have been calculated as 23,065 kWe and 6924 m², respectively.

Potential Geothermal Energy Utilization in Jordan: Possible Electrical Power Generation

Abstract Jordan, which is considered as part of the ring of fire, is tectonically active and could be considered as potential region for future generation of energy from the available geothermal energy resources. The current article discusses the possibility of utilizing geothermal energy in generating electrical power in Jordan. Jordan encounters geothermal energy resources in two main forms, medium and low energy with variation of temperature ranges from 110–114 o C and 30–65 o C, respectively. The various hot springs and wells have been subjected to a comparison in terms of temperature and flow rate in order to determine the most suitable method for electric power generation. This comparison concluded that electrical power could be generated using geothermal binary power plants and geothermal Stirling engines. Keywords: Geothermal Energy, Groundwater, Binary Power plant, Stirling Engine 1. Introduction With escalating awareness of the damaging effects of using fossil fuels on the environment, there has been a growing attention to provide the region with an abundant, clean renewable baseload energy sources. Renewable energy technologies are being developed to attain such clean sources of energy that have much lower negative impact on environment. In this regard, renewable energy resources appear to be a potential solution to energy and environmental problems and the key to the sustainable development. According to [1], the geothermal energy is stored between the earth's surface and a specified depth in the crust. It is measured from local average annual temperature beneath a specified area. The most common criterion for classifying geothermal resources is based on the enthalpy of the geothermal fluids that act as the carrier transporting heat from the deep hot rocks to the surface. Enthalpy, which can be considered more or less proportional to the temperature, is used to express the heat content of the fluids, and gives a rough idea of their value. According to criteria that are generally based on the energy content of the fluids and their potential forms of utilization [2], the resources are divided into low, medium and high temperature resources. Thousands megawatts of power are currently being produced could be developed from already-identified hydrothermal resources. With improvements in technology, much more power will be available. Usable geothermal resources will not be limited to the shallow hydrothermal reservoirs at the crustal plate boundaries. Much of the world is underlain by dry hot rock. Scientists worldwide have experimented piping water into this deep hot rock to create more hydrothermal resources that can be used in geothermal power plants [3]. As drilling technology being developed, allowing to drill much deeper, geothermal energy from hot dry rock could be available everywhere. At such time, we will be able to hit the true potential of the huge heat resources of the earth's crust and to create more efficient energy supply. A complex plate boundary crosses Turkey and Greece where several high-temperature geothermal prospects have been found. Since 1984, the Kizildere field in western Turkey has produced 20.4 MWe. A dry ice plant was built in the late 80s. Lower temperature hot water (552 GWh/yr) is used for heating and in greenhouses in Turkey [4]-[7]. In Greece 37 GWh/yr is used directly, and in Milos a 2 MWe flash plant was operated for several years. Geothermal hot water is used in Algeria (460 GWh/yr) and Tunisia (400 GWh/yr) for bathing, greenhouses, drinking and irrigation purposes. In Israel and Jordan, the Red Sea-Jordan Valley Rift (JVR) hosts hot springs, with temperature up to 102

Life cycle assessment of geothermal binary power plants using enhanced low-temperature reservoirs

Geothermal binary power plants that use low-temperature heat sources have gained increasing interest in the recent years due to political efforts to reduce greenhouse gas emissions and the consumption of finite energy resources. The construction of such plants requires large amounts of energy and material. Hence, the question arises if geothermal binary power plants are also environmentally promising from a cradle-to-grave point of view. In this context, a comprehensive Life Cycle Analysis (LCA) on geothermal power production from EGS (enhanced geothermal systems) low-temperature reservoirs is performed. The results of the analysis show that the environmental impacts are very much influenced by the geological conditions that can be obtained at a specific site. At sites with (above-) average geological conditions, geothermal binary power generation can significantly contribute to more sustainable power supply. At sites with less favorable conditions, only certain plant designs can make up for the energy and material input to lock up the geothermal reservoir by the provided energy. The main aspects of environmentally sound plants are enhancement of the reservoir productivity, reliable design of the deep wells and an efficient utilization of the geothermal fluid for net power and district heat production.

Development of geothermal power engineering technologies in Russia

The present state of geothermal power engineering in Russia and prospects for its development are considered. An assessment is given of the projects of constructing a pilot binary geothermal power plant in Kamchatka, developing geothermal heat supply systems in the town of Vilyuchinsk and settlement of Rozovyi, and increasing the installed capacity of the Mutnovsk geothermal power station, which are the top-priority projects implemented by OAO RusGidro with scientific and technical support from ZAO GEOINKOM and ZAO Geoterm-EM.

Exergetic analysis of various types of geothermal power plants

Based on available surveys, it has been shown that Iran has substantial geothermal potential in the north and north-western provinces, where in some places the temperature reaches 240 °C. In order to better exploit these renewable resources, it is necessary to study this area. Thus, the aim of this paper is a comparative study of the different geothermal power plant concepts, based on the exergy analysis for high-temperature geothermal resources. The considered cycles for this study are a binary geothermal power plant using a simple organic Rankine cycle (ORC), a binary geothermal power plant using an ORC with an internal heat exchanger (IHE), a binary cycle with a regenerative ORC, a binary cycle with a regenerative ORC with an IHE, a single-flash geothermal power plant, a double-flash geothermal power plant and a combined flash-binary power plant. With respect to each cycle, a thermodynamic model had to be developed. Model validation was undertaken using available data from the literature. Based on the exergy analysis, a comparative study was done to clarify the best cycle configuration. The performance of each cycle has been discussed in terms of the second-law efficiency, exergy destruction rate, and first-law efficiency. Comparisons between the different geothermal power plant concepts as well as many approaches to define efficiencies have been presented. The maximum first-law efficiency was found to be related to the ORC with an IHE with R123 as the working fluid and was calculated to be 7.65%. In contrast, the first-law efficiency based on the energy input into the ORC revealed that the binary cycle with the regenerative ORC with an IHE and R123 as the working fluid has the highest efficiency (15.35%). Also, the maximum first-law efficiency was shown to be given by the flash-binary with R123 as the working fluid and was calculated to be 11.81%.

Investigation of Geothermal Energy Use in Gas Liquefaction

In this paper, we propose the use of geothermal energy for gas liquefaction, and investigate three possible cases for accomplishing such a task: using geothermal output work as the input for a liquefaction cycle; using geothermal energy in an absorption refrigeration process to precool the gas before the gas is liquefied in a liquefaction cycle; and using geothermal energy both for the absorption refrigeration to precool the gas as well as to produce work and use it in a liquefaction cycle (i.e., cogeneration). A binary geothermal power plant is considered for power production, while the Linde-Hampson cycle is considered for liquefaction. A liquid geothermal resource at 165°C is considered and both the ideal (i.e., reversible) and non-ideal (e.g., irreversible) system operations are analyzed. A procedure for such an investigation is developed and certain performance parameters are defined. Also, the effects of geothermal water temperature and gas precooling temperature on the system performance parameters are studied. The results show that there is a significant amount of energy savings potential in the liquefaction work requirement as a result of precooling the gas in a geothermal absorption cooling system, which indicates that it makes thermodynamic sense to use geothermal energy for absorption cooling rather than to use it for power generation.

Performance and parametric investigation of a binary geothermal power plant by exergy

Exergy analysis of a binary geothermal power plant is performed using actual plant data to assess the plant performance and pinpoint sites of primary exergy destruction. Exergy destruction throughout the plant is quantified and illustrated using an exergy diagram, and compared to the energy diagram. The sites with greater exergy destructions include brine reinjection, heat exchanger and condenser losses. Exergetic efficiencies of major plant components are determined in an attempt to assess their individual performances. The energy and exergy efficiencies of the plant are 4.5% and 21.7%, respectively, based on the energy and exergy of geothermal water at the heat exchanger inlet. The energy and exergy efficiencies are 10.2% and 33.5%, respectively, based on the heat input and exergy input to the binary Rankine cycle. The effects of turbine inlet pressure and temperature and the condenser pressure on the exergy and energy efficiencies, the net power output and the brine reinjection temperature are investigated and the trends are explained.

An Applied Research Program on Water Desalination with Renewable Energies

The use of renewable energy for desalination might be quite different in many places of the world. In Mexico, specifically in Baja California, there is an abundance of traditional renewable resources like sun and wind but also some others like hot springs at the coast, tidal currents and tidal amplitudes of over six meters in the upper part of the Gulf of California associated with a severe scarcity of fresh water. The National University of Mexico (UNAM) started two years ago a well organized research program to assess the amount of these resources and to find the way to use them for desalinating sea water. Very exiting results have being obtained: The abundance of hot springs at the shore, some of them over 84°C, lead to the design of thermal desalinating prototype plants with very little energy consumption. It was found by geochemistry that at a few meters deep, some 50 m, very high temperature can be obtained, easy to use in binary geothermal power plants to generate electricity for desalination. During the survey it was found that the amount of electrical power that can be generated with tidal storage and from deep sea hydrothermal vents is of the order of several thousands of MW. A special approach is also presented for the use of solar energy and the tidal currents of the Gulf. The IMPULSA research group at UNAM has been already consolidated with more than 30 students, dedicated to the design of appropriate equipment to make use of these resources and to characterize and quantify this huge amount of renewable energies that will permit to desalinate sea water.

Geothermal energy use in hydrogen liquefaction

We propose the use of geothermal energy for hydrogen liquefaction, and investigate three possible cases for accomplishing such a task including (1) using geothermal output work as the input for a liquefaction cycle; (2) using geothermal heat in an absorption refrigeration process to precool the gas before the gas is liquefied in a liquefaction cycle; and (3) using part of the geothermal heat for absorption refrigeration to precool the gas and part of the geothermal heat to produce work and use it in a liquefaction cycle (i.e., cogeneration). A binary geothermal power plant is considered for power production while the precooled Linde–Hampson cycle is considered for hydrogen liquefaction. A liquid geothermal resource is considered and both ideal (i.e., reversible) and non-ideal (e.g., irreversible) system operations are analyzed. A procedure for such an investigation is developed and appropriate performance parameters are defined. Also, the effects of geothermal water temperature and gas precooling temperature on system performance parameters are studied. The results show that there is a significant amount of energy savings potential in the liquefaction work requirement as a result of precooling the gas in a geothermal absorption cooling system. Using geothermal energy in a cogeneration scheme (power production and absorption cooling) also provides significant advantages over the use of geothermal energy for power production only.

Ideal thermal efficiency for geothermal binary plants

The Carnot cycle is reviewed as to its appropriateness to serve as the ideal model for geothermal binary power plants. It is shown that the Carnot cycle sets an unrealistically high upper limit on the thermal efficiency of these plants. A more useful model is the triangular (or trilateral) cycle because binary plants operating on geothermal hot water use a non-isothermal heat source. The triangular cycle imposes a lower upper bound on the thermal efficiency and serves as a more meaningful ideal cycle against which to measure the performance of real binary cycles. Carnot and triangular cycle efficiencies are contrasted and the thermal efficiencies of several actual binary cycles are weighed against those of the ideal triangular cycle to determine their relative efficiencies. It is found that actual binary plants can achieve relative efficiencies as high as 85%. The paper briefly discusses cycles using two-phase expanders that in principle come close to the ideal triangular cycle.

Possibilities of implementation of absorption heat pump in realization of the Clausius–Rankine cycle in geothermal power station

The topic of utilization of geothermal power for heating purposes in Poland is relatively well known, which is justified by the fact of a number of operating geothermal power plants and some other installations in a well advanced design stage. Geothermal energy utilization projects for production of electricity are also under development. The results of one of such analysis, regarding the correctness of construction and operation of a binary geothermal power plant in combination with the heat pump, supplied by heat water with low enthalpy, has been discussed in the present paper.

Exergy analysis and pressure optimisation of geothermal binary power plants

Binary geothermal power plants are used for power production from moderate temperature geothermal reservoirs (85-170°C). In performance analysis of those plants, the second law of thermodynamics is used like in other conventional power plants. In this paper, the exergy analysis and pressure optimisation methods are described for binary power plants. The method described is applied to a hypothetical geothermal reservoir for Turkey and a performance analysis is made of the binary power plant and its major equipment. The computer software developed is used to show the variations of performance criteria. According to the results, overall first and second law efficiencies of the hypothetical binary power plant have been determined to be 9.065 and 34.94% respectively for a reservoir temperature of 150°C and geofluid flowrate of 250 kg/s.

04/03144 The function estimation in predicting heat flux ofpin fins with variable heat transfer coefficients: Lee, H.-L. et al. Energy Conversion and Management, 2004, 45, (11–12), 1749–1758

Thermodynamic energy and exergy analysis of a PEM water electrolyzer driven by geothermal power for hydrogen production is performed. For this purpose, work is produced from a geothermal resource by means of the organic Rankine cycle; the resulting work is used as a work input for an electrolysis process; and electrolysis water is preheated by the waste geothermal water. The first and second-law based performance parameters are identified for the considered system and the system performance is evaluated. The effects of geothermal water and electrolysis temperatures on the amount of hydrogen production are studied and these parameters are found to be proportional to each other. We consider a geothermal resource at 160 °C available at a rate of 100 kg/s. Under realistic operating conditions, 3810 kW power can be produced in a binary geothermal power plant. The produced power is used for the electrolysis process. The electrolysis water can be preheated to 80 °C by the geothermal water leaving the power plant and hydrogen can be produced at a rate of 0.0340 kg/s. The energy and exergy efficiencies of the binary geothermal power plant are 11.4% and 45.1%, respectively. The corresponding efficiencies for the electrolysis system are 64.0% and 61.6%, respectively, and those for the overall system are 6.7% and 23.8%, respectively.

03/01742 Exergy analysis of a dual-level binary geothermal power plant: Kanoglu, M. Geothermics, 2002, 31, (6), 709–724

03/01742 Exergy analysis of a dual-level binary geothermal power plant: Kanoglu, M. Geothermics, 2002, 31, (6), 709–724

Exergy analysis of a dual-level binary geothermal power plant

Exergy analysis of a 12.4 MW existing binary geothermal power plant is performed using actual plant data to assess the plant performance and pinpoint sites of primary exergy destruction. Exergy destruction throughout the plant is quantified and illustrated using an exergy flow diagram, and compared to the energy flow diagram. The causes of exergy destruction in the plant include the exergy of the working fluid lost in the condenser, the exergy of the brine reinjected, the turbine-pump losses, and the preheater–vaporizer losses. The exergy destruction at these sites accounts for 22.6, 14.8, 13.9, and 13.0% of the total exergy input to the plant, respectively. Exergetic efficiencies of major plant components are determined in an attempt to assess their individual performances. The exergetic efficiency of the plant is determined to be 29.1% based on the exergy of the geothermal fluid at the vaporizer inlet, and 34.2% based on the exergy drop of the brine across the vaporizer–preheater system (i.e. exergy input to the Rankine cycle). For comparison, the corresponding thermal efficiencies for the plant are calculated to be 5.8 and 8.9%, respectively.

Improving the Performance of an Existing Air-Cooled Binary Geothermal Power Plant: A Case Study

An existing air-cooled binary geothermal power plant in northern Nevada is studied. The current performance of the plant is analyzed with an emphasis on the effects of seasonal climate changes. Two potential sites have been identified to improve the performance of the plant. Northern Nevada has a dry climate, particularly in hot summer months, and the temperature of cooling air can be decreased considerably by evaporative cooling. When the air temperature is decreased to the wet-bulb temperature, the decrease in the condenser temperature is determined to increase the power output by up to 29 percent. The required amount of water for this case is calculated to be about 200,000 tons per yr. Several parametric studies are performed by simulating the operation of the plant with an equation solver with built-in thermophysical property functions. It is determined that the net power output of the plant can be increased by 2.8 percent by optimizing the maximum pressure in the cycle. Also, replacing the existing working fluid isobutane by other commonly used binary fluids such as butane, R-114, isopentane, and pentane do not produce as much of an improvement in the plant performance as operating with isobutane at the optimum maximum pressure. Therefore, isobutane appears to be the best choice for this power plant.

Value analysis of advanced heat rejection systems for geothermal power plants

A computer model is developed to evaluate the performance of the binary geothermal power plants (Organic Rankine Cycles) with various heat rejection systems and their impact on the levelized cost of electricity.