Abstract:
Methods, apparatuses, and embodiments related to estimating void fractions in real-time or substantially real-time without disrupting a production flow of, e.g., a geothermal power plant. Some embodiments describe methods and systems of determining void fraction of a two-phase mixture extracted from a geothermal well by measuring the attenuations of one or more radiofrequency signals in a fixed span of a transportation unit (e.g., a pipe). Depending on void fraction of the two-phase mixture in the transportation, the RF signals would attenuate differently across the fixed span. For example, a monitor system can utilize one or more transmitter antennas in the transportation unit to transmit one or more RF signals and utilize one or more receiver antennas to measure attenuations of these RF signals over the fixed span. In some embodiments, an antenna can be configured to serve as both a transmitter antenna and a receiver antenna.

Description:
CROSS REFERENCE TO RELATED APPLICATION(S) 
       [0001]    This application is a continuation application of International Application No. PCT/US2015/056251, filed Oct. 19, 2015, which claims the benefit of U.S. Provisional Patent Application No. 62/067,377, filed Oct. 22, 2014 both of which are incorporated herein in their entirety by reference. 
     
    
     RELATED FIELD 
       [0002]    At least one embodiment of this disclosure relates generally to a geothermal system, and in particular to determining void fraction in a geothermal system. 
       BACKGROUND 
       [0003]    Supply of energy resources across the globe is becoming scarce. Various alternative energy sources have been explored, including solar, wind, tidal, and geothermal. Because all of these alternative sources may be unpredictable, various systems have been implemented to accurately and consistently estimate and model the energy output and characteristics of these sources. 
         [0004]    Geothermal energy is thermal energy generated and stored in the Earth. From hot springs or other thermal vents, geothermal energy can be extracted and converted into electrical energy. For geothermal, the measurement of void fraction from each geothermal well/vent/spring enables the operators of geothermal wells to calculate the total enthalpy of the two-phase fluids produced from the well, and hence, estimate the energy output. Void fraction or porosity is a measure of the void (i.e., “empty”) spaces in a material, and a fraction of the volume of voids over the total volume. For example, the void fraction can be expressed as between 0 and 1 or as a percentage between 0 and 100%. A pump can extract both steam and water (e.g., brine) out of a geothermal vent, creating a gas-liquid two-phase flow. The void fraction can be defined as the fraction of the flow channel volume that is occupied by the gas phase (e.g., steam) or, alternatively, as the fraction of the cross-sectional area of the channel that is occupied by the gas phase. 
         [0005]    Conventional techniques of measuring void fraction mostly involve taking the geothermal system out of commission temporarily. For example, a conventional method involves redirecting the output flow from a geothermal well into a separator/silencer assembly to measure the ratio of steam flow and water flow. For another example, the output flow may be redirected into a pressure-controlled pipe to estimate the void fraction. These techniques are disruptive to the energy production cycle of a geothermal power plant. 
         [0006]    Recent developments led to a technique of measuring the void fraction via precise metered injection of liquid and vapor phase tracers into the two-phase production pipeline and sampling each phase downstream of the injection point. While this technique does not disrupt the production pipeline, this technique does require additional lab work and does not provide instantaneous feedback of the geothermal well&#39;s performance. 
       DISCLOSURE OVERVIEW 
       [0007]    Some embodiments disclose techniques for estimating void fractions in real-time or substantially real-time without disrupting the production flow of the geothermal power plant. Some embodiments describe methods and systems of determining void fraction of a two-phase mixture extracted from a geothermal well by measuring the attenuations of one or more radiofrequency (RF) signals in a fixed span of a transportation unit (e.g., a pipe). Depending on void fraction of the two-phase mixture in the transportation, the RF signals would attenuate differently across the fixed span. For example, a monitor system can utilize one or more transmitter antennas in the transportation unit to transmit one or more RF signals and utilize one or more receiver antennas to measure attenuations of these RF signals over the fixed span. In some embodiments, an antenna can be configured to serve as both a transmitter antenna and a receiver antenna. For example, a chain of antennas can enable the monitor system to measure RF signal attenuation across multiple sequential spans of the transportation unit. In some embodiments, each antenna is configured to serve as either a transmitter antenna or a receiver antenna. For example, pairs of transmitter antenna and receiver antenna can be distributed within the transportation unit. 
         [0008]    The void fraction changes when the ratio between liquid brine and geothermal vapor (e.g., steam and/or other gases) changes. When the ratio between the liquid brine and the geothermal vapor changes, the attenuation of the RF signals traversing through the two-phase mixture also changes (e.g., more liquid leads to higher attenuation). In some embodiments, the structure of antennas are adapted with aerodynamic and/or hydrodynamic designs (e.g., protected with a hydrodynamic and aerodynamic shield) to avoid breakage or damage from sudden movements of the two-phase mixture. In some embodiments, the antennas are secured onto the transformation unit with dampeners to prevent damages due to large oscillations or vibrations of the transportation unit. The attenuation values can be averaged (e.g., 5 minute intervals) to determine the void fraction of the mixture in real-time (e.g., by a moving average). In some embodiments, the signal attenuation can be computed logarithmically, such as in units of decibels. 
         [0009]    Some embodiments of this disclosure have other aspects, elements, features, and steps in addition to or in place of what is described above. These potential additions and replacements are described throughout the rest of the specification 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0010]      FIG. 1  is a diagram illustrating a geothermal power plant, in accordance with various embodiments. 
           [0011]      FIG. 2  is a block diagram illustrating a void fraction monitor, in accordance with various embodiments. 
           [0012]      FIG. 3  is a flow chart of a method of operating a void fraction monitor at a geothermal power plant, in accordance with various embodiments. 
           [0013]      FIG. 4  is a block diagram of an example of a computing device, which may represent one or more computing device or server described herein, in accordance with various embodiments. 
       
    
    
       [0014]    The figures depict various embodiments of this disclosure for purposes of illustration only. One skilled in the art will readily recognize from the following discussion that alternative embodiments of the structures and methods illustrated herein may be employed without departing from the principles of the invention described herein. 
       DETAILED DESCRIPTION 
       [0015]      FIG. 1  illustrates a geothermal power plant  100 , in accordance with various embodiments. The geothermal power plant  100  comprises a geothermal well  102  producing a two-phase mixture  104 , such as saturated steam and hot brine, taken via an extraction unit  106 . The two-phase mixture  104  is then transported via a transportation unit  108  (e.g., a pipe) to a separator  110 . In some embodiments, the separator  110  can be connected to multiple transportation units, such as the transportation unit  108 , each conveying two-phase mixture from a different geothermal well, such as the geothermal well  102 . The separator  110  can balance the pressure of the two-phase mixtures coming from all of the transportation units. The separator  110  separates geothermal vapor  112  (e.g., the saturated steam and non-condensable gases) from geothermal liquid  114 . The separator  110  then supplies the geothermal vapor  112  to a generator unit  116 . 
         [0016]    The generator unit  116 , for example, can be a turbogenerator including a turbine  116 A driving an electric generator  116 B. The generator unit  116  extracts heat (e.g., stored in enthalpy) from the steam and produces power, such as electrical power. In some embodiments, the heat-depleted steam exhausted from the generator unit  116  is condensed via a condenser  118  that is supplied with cooling water or other coolant. Water vapor and other non-condensable gases are vented to the atmosphere and hot brine produced from the separator  110  is collected and conveyed back to the geothermal well or to a storage area. 
         [0017]    In various embodiments, the geothermal power plant  100  also includes a void fraction monitor  120 . The void fraction monitor  120  can determine the void fraction of the two-phase mixture  104  without disrupting the operation of the generator pipeline. The void fraction monitor  120  can determine a real-time or substantially real-time void fraction of the two-phase mixture  104  in the transportation unit  108  by measuring attenuation of an RF signal traveling through the two-phase mixture  104  in the transportation unit  108 . In some embodiments, the void fraction monitor  120  can measure attenuations of multiple RF signals (e.g., at different modulations or frequencies) traveling through the two-phase mixture  104 . In some embodiments, the void fraction monitor  120  can measure attenuations of multiple RF signals traveling through the two-phase mixture  104  in different segments of the transportation unit  108 . In some embodiments, the void fraction monitor  120  is implemented with at least an antenna for transmitting an RF signal, an antenna for receiving the RF signal, control circuitry to modulate/transmit the RF signal, control circuitry to receive/measure the RF signal, and a computer system to compute the void fraction based on the attenuation of the RF signal. 
         [0018]      FIG. 2  is a block diagram illustrating a void fraction monitor  200 , in accordance with various embodiments. The void fraction monitor  200 , for example, can be the void fraction monitor  120  of  FIG. 1 . The void fraction monitor  200  can be coupled to a transportation unit  202 , such as the transportation unit  108  of  FIG. 1 . The void fraction monitor  200  includes one or more antennas  204  (e.g., a transmitter antenna  204 A and a receiver antenna  204 B). The antennas  204  may be secured onto an inner side of the transportation unit  202  via an attachment mechanism  206 . The attachment mechanism  206 , for example, can be a fastener, a clip, or a joint. The attachment mechanism  206  can also include a dampening structure to protect the antennas  204  from overstressing or being damaged by vibrations of the transportation unit  202  or oscillations (e.g., by slug flow) of the two-phase mixture in the transportation unit  202 . The antennas  204  can be adapted with a hydrodynamic or aerodynamic shield that prevents it from being damaged by slug flow. 
         [0019]    A driver circuitry  205  can power the transmitter antenna  204 A to send an RF signal towards the receiver antenna  204 B. In some embodiments, the RF signal is a directional RF signal. In some embodiments, the RF signal is an omni-directional RF signal. In various embodiments, measuring the attenuation of an RF signal is advantageous over measuring attenuation of a light beam. A light beam requires a line of sight, and hence the alignment of a light emitter and an optical sensor need to be precise. The RF signal on the other hand can bounce multiple times on an inner surface of the transportation unit  202 , and still be captured by a receiver antenna. While an optical sensor can be blinded or covered by debris, a receiver antenna generally do not get blinded by debris. 
         [0020]    In some embodiments, RF signal is within the microwave frequency range (e.g., 300 MHz to 300 GHz). In some embodiments, the driver circuitry  205  includes an amplifier and/or a modulator. The driver circuitry  205  can have its own power source, or receive power (AC or DC) from a power supply outside of the transportation unit  202 . 
         [0021]    In a particular example, the driver circuitry  205  includes a noise source (e.g., a diode driven in reverse to generate a broadband white noise) coupled to a microwave amplifier. In some embodiments, the driver circuitry  205  can use a modulator instead or in addition to the noise source. The modulator may be capable of generating specific signal patterns at specific frequencies. The microwave amplifier can be coupled to a circulator. Because of the changes in the void fraction that the transmitter antenna  204 A is immersed in, the impedance at the transmitter antenna  204 A can vary drastically. The circulator can act as a duplexer/isolator to re-route any reverse signal that bounces back from transmitter antenna  204 A. For example, a reverse signal may fry the microwave amplifier without the presence of the circulator. The circulator is coupled to the microwave amplifier at a first port and to the transmitter antenna  204 A at a second port. The circulator re-routes the reverse signal to a third port. The driver circuitry  205  can measure the reverse/reflected signal strength to determine how much of transmitted power has been reflected back. The void fraction monitor  200  can thus determine the attenuation through the two-phase mixture by subtracting the inputting power by both the received power at the receiver antenna  204 B and the reverse signal power at the transmitter antenna  204 A. 
         [0022]    A receiver circuitry  207  can be coupled to the receiver antenna  204 B to interpret the RF signal received by the receiver antenna  204 B. Because the attenuation of the RF signal traveling through the two-phase mixture in the transportation unit  202  may be high, the receiver circuitry  207  can include a pre-amp before measuring the RF signal. In some embodiments, the receiver circuitry  207  can include a RF power meter (e.g., a diode and a capacitor) to measure the received power regardless of the frequency. In some embodiments, the receiver circuitry  207  can include a receiver, a filter, a demodulator, a detector, a software-defined radio (SDR), a spectrum analyzer, or any combination thereof, to determine the attenuation of the RF signal at one or more preset frequencies. In the embodiments where the receiver circuitry  207  can measure attenuation levels at different frequencies, the receiver circuitry  207  can share those additional information with a computing system of the void fraction monitor  200  to derive additional information about the two-phase mixture other than void fraction (e.g., carbon dioxide content or other content). The void fraction monitor can then determine the void fraction associated with the levels of attenuation at the preset frequencies. For example, 3 dB of attenuation at a 1.5 GHz frequency can correspond to approximately 2% change in void fraction. 
         [0023]    In some embodiments, the transportation unit  202  includes an orifice plate  208  therein that measures velocity of flow and/or pressure of the mixture in the transportation unit. In some embodiments, the transportation unit  202  includes a temperature sensor  210  therein that measures the temperature of the mixture. In some embodiments, the transportation unit  202  includes a wireless transceiver  212 . The wireless transceiver  212  can transmit the pressure measurement, the temperature measurement, and the attenuation measurements to a computing system  214 . In some embodiments, the computing system  214  is located within the transportation unit  202 . In some embodiments, the computing system  214  is located outside of the transportation unit  202 . In some embodiments, the computer system  214  can be directly coupled via one or more wires/cables to the orifice plate  208 , the temperature sensor  210 , the receiver circuitry  207  (e.g., reporting the received signal power or the attenuation), the transmitter circuitry  205  (e.g., reporting the inputting signal strength and/or the reflected/reverse signal strength), or any combination thereof. 
         [0024]    The computing system  214  can compute the void fraction using the changes in average attenuation at one or more frequencies (or average of changes in the attenuation) as measured at the receiver circuitry  207 . The computing system  214  can then compute the total heat content (e.g., enthalpy) extracted from the geothermal well through the transportation unit  202  based on the pressure measurement, the temperature measurement, and the void fraction estimation. 
         [0025]    The computing system  214  can be implemented by one or more computing devices, such as a single processor or multi-processor computer, a distributed computing cluster, a virtualized operating system hosted by a cloud server farm, etc. The computing system  214  can implement one or more functional modules (e.g., as software component or hardware component in the computing system  214 ). For example, the computing system  214  can include a void fraction estimation module  216 , an enthalpy estimation module  217 , a user interface module  218 , a generator control module  220 , a post-processing control module  222 , and a geothermal modeling module  224 . 
         [0026]    The void fraction estimation module  216  can receive the attenuation measurements from the receiver circuitry  207 . The void fraction estimation module  216  can use the attenuation values to compute the void fraction of the two-phase mixture in the transportation unit  202  in substantially real-time. The void fraction estimation module  216  can also normalize out noise patterns in the attenuation measurements attributed to various phenomenon of a two-phase mixture flow. For example, the void fraction estimation module  216  can estimate the void fraction via differences between moving averages or periodic averages of attenuation measurements. Alternatively, the void fraction estimation module  216  can estimate the void fraction via averages of the differences between attenuation measurements. 
         [0027]    The void fraction estimation module  216  can implement “virtual dampeners” that analyzes the chaotic signal being obtained from the antennas  204  and normalize out any static signal to get a clearer estimation of the void fraction. When the static signal is discounted, the average attenuation of the transportation unit and content inside can be monitored to estimate the void fraction of the content. 
         [0028]    Based on the void fraction estimation, velocity flow/pressure information, and/or temperature information, the enthalpy estimation module  217  can dynamically compute enthalpy in the content of the transportation unit  202  in real-time. This enthalpy estimation can be presented via the user interface module  218 . The user interface module  218  can present information about the geothermal well on a display device, via webpage, via an application programming interface (API), an audio speaker, or any combination thereof. 
         [0029]    In some embodiments, the estimated enthalpy can be used to control the generator at the geothermal power plant via the generator control module  220 , such as controlling a valve to the turbine coupled to the generator. In some embodiments, the estimated enthalpy and the estimated void fraction can be used to control the postprocessing of the geothermal content (e.g., steam and brine) via the postprocessing control module  222 . For example, decreasing enthalpy can indicate breakthrough of injection water or invasion of cooler groundwater. Hence, upon detecting decreasing enthalpy, the postprocessing control module  222  can temporarily stop or decrease the injection of water down the geothermal well. For another example, increasing enthalpy can indicate reservoir boiling and the formation of a steam cap. In some cases, enthalpy is essential for the interpretation of geochemical data because it determines the steam fraction at sampling conditions and allows the correction of chemical concentrations back to reservoir conditions 
         [0030]    The geothermal modeling module  224  can use the real-time sensor data from the temperature sensor  210 , the receiver circuitry  207 , and the orifice plate  208  to determine context information about the heat production from the geothermal well. In some cases, the geothermal modeling module  224  can determine potential failure points in the geothermal power plant. For example, a first pattern of noisy variations in attenuation measurements may trigger an alert that a valve is chattering and about to fail. For another example, a second pattern of noisy variations in attenuation measurements may trigger an alert of the occurrence of slug flow. Unlike convention geothermal reservoir models that are static in nature, the geothermal modeling module  224  can maintain a real-time, dynamic model of a geothermal reservoir (e.g., multiple geothermal wells) based on the real-time enthalpy content (e.g., computed from the void fraction) produced from the geothermal wells of the geothermal reservoir. 
         [0031]    The geothermal modeling module  224  can alert a user through the user interface module  218  when a slug flow pattern is determined. Slug flow pattern prediction can be achieved by monitoring the flow velocity with the orifice plate  208  and/or estimation of the void fraction. The combined information from the orifice plate  208  and the dynamic estimation of void fraction enables the geothermal modeling module  224  to detect onset triggers of slug flow and/or cyclical patterns of slug flow. This is advantageous over traditional systems that lack the ability to dynamically estimate void fraction during production. These contextual patterns, including slug flow patterns, can be time-stamped and tagged with other metadata (e.g., location, magnitude, frequency, etc.) such that the onset of these patterns (e.g., slug flow) can be compared with other phenomenon being measured around the steam field of the geothermal well or geothermal wells of the same reservoir. 
         [0032]    In some embodiments, the geothermal modeling module  224  can be used to model the reservoir underneath the geothermal well by combining data from multiple geothermal wells connecting to the same reservoir. Traditionally, because void fraction cannot be tracked in real-time, modeling of a reservoir is accomplished by building a static reservoir model to balance the extraction of the two-phase mixture from different geothermal wells and re-injection of the water/liquid back to the geothermal wells. In some embodiments, the geothermal modeling module  224  can generate a 3D map of the reservoir based on the locations of the geothermal wells. The 3D map can illustrate a heat map corresponding to the enthalpy computed by the computing system  214  in real-time. With multiple geothermal wells monitored, and all the results aggregated in a 3D spatial model/display, for example, the geothermal modeling module  224  can accurate predict trigger-based and cyclical behaviors of a geothermal well or reservoir. The triggers and cycles of these behaviors can be identified using statistical analysis (e.g., principal component analysis and/or regression), signal analysis (e.g., Fourier transform and/or auto-correlation) and/or machine learning (e.g., Hidden Markov Model or Gaussian Mixture Model). 
         [0033]    Portions of active components (e.g., sensors, computing devices, functional modules, etc.) associated with the void fraction monitor  200  may be implemented in the form of special-purpose circuitry, in the form of one or more appropriately programmed programmable processors, a single board chip, a field programmable gate array, a network capable computing device, a virtual machine, a cloud-based terminal, or any combination thereof. For example, the components described can be implemented as instructions on a tangible storage memory capable of being executed by a processor or other integrated circuit chip. The tangible storage memory may be volatile or non-volatile memory. In some embodiments, the volatile memory may be considered “non-transitory” in the sense that it is not transitory signal. Memory space and storages described in the figures can be implemented with the tangible storage memory as well, including volatile or non-volatile memory. 
         [0034]    Each of the components may operate individually and independently of other components. Some or all of the components may be executed on the same host device or on separate devices. The separate devices can be coupled through one or more communication channels (e.g., wireless or wired channel) to coordinate their operations. Some or all of the components may be combined as one component. A single component may be divided into sub-components, each sub-component performing separate method step or method steps of the single component. 
         [0035]    In some embodiments, at least some of the components share access to a memory space. For example, one component may access data accessed by or transformed by another component. The components may be considered “coupled” to one another if they share a physical connection or a virtual connection, directly or indirectly, allowing data accessed or modified from one component to be accessed in another component. In some embodiments, at least some of the components can be upgraded or modified remotely (e.g., by reconfiguring executable instructions that implements a portion of the components). The void fraction monitor  200  may include additional, fewer, or different components for various applications. 
         [0036]      FIG. 3  is a flow chart of a method  300  of operating a void fraction monitor (e.g., the void fraction monitor  200  of  FIG. 2 ) at a geothermal power plant, in accordance with various embodiments. The method  300  begins at step  302  of configuring normalization parameters for estimating the void fraction. For example, the normalization parameters can include the levels of RF signal strength that a transmitter circuitry used. The normalization parameters can include an expected signal attenuation pattern (e.g., a spectral analysis pattern) when the two-phase mixture is completely vapor, when the two-phase mixture is completely liquid, and/or when the transportation pipe is empty. 
         [0037]    In some embodiments, a computing system (e.g., the computing device  400  of  FIG. 4 ) of the void fraction monitor can present an interface (e.g., a display and keyboard or a touchscreen) for a user to input the normalization parameters. In some embodiments, the normalization parameters can be estimated based on contextual information. For example, the user can input the length and thickness of the transportation pipe, and the computing system can estimate the attenuation pattern based on that information. The computing system can also estimate an expected signal strength variance due to noise rather than changes in void fraction. 
         [0038]    In some embodiments, the computing system can calibrate the void fraction estimation algorithm prior to production operation of a geothermal well. For example, the computing system can instruct the transmitter circuit transmit when a transportation pipe is empty, when the transportation pipe is full of vapor, or when the transportation pipe is full of liquid. The computing system can collect the received signal strength (e.g., from the receiver circuit), the inputting signal strength (e.g., from the transmitter circuit), and the reflected/reverse signal strength (e.g., from the transmitter circuit) to determine the expected attenuation patterns at the upper and lower void fraction limits. 
         [0039]    At step  304 , a transmitter circuit can transmit an RF signal through a transportation pipe during production operation of the geothermal well. The transportation pipe may be conveying a two-phase mixture extracted from the geothermal well when the RF signal is transmitted. The RF signal propagates through the two-phase mixture. In turn, the two-phase mixture attenuates the signal strength of the RF signal. 
         [0040]    A receiver antenna then captures the RF signal at a fixed distance away from the transmitter antenna. At step  306 , a receiver circuit measures signal strength attenuation of the RF signal received at the receiver antenna. 
         [0041]    In order to optimize the steam field to achieve an optimal efficiency, the void fraction monitor has to discern changes in the void fraction of the two-phase mixture within a certain resolution. Because the resolution of the void fraction estimation corresponds directly to signal attenuation measured at the receiver circuit, the initial signal strength modulated by the transmitter circuit can be increased when the receiver circuit is unable to detect the RF signal, such as when the signal attenuation is too high. Alternatively, a preamp at the receiver circuit can be selectively activated when the signal attenuation is too high. By selectively raising the initial signal strength and/or selectively using the preamp, the resolution of attenuation readings can be adjusted to match the resolution needed for estimating void fraction. 
         [0042]    In some embodiments, steps  304  and  306  are repeated iteratively. To ensure that the power of the RF signal does not fry the circuitry used, the transmitter circuit can employ a feedback mechanism to determine the power used to modulate the RF signal. In some embodiments, the receiver circuit can communicate with the transmitter circuit. For example, the receiver circuit can communicate with the transmitter circuit via a cable or wirelessly. This enables the receiver circuit to provide feedback to the transmitter circuit. When the signal attenuation is too high (e.g., above a threshold), the transmitter circuit can then increase the initial signal strength to modulate the RF signal. When the received signal strength is too high (e.g., above a threshold) at the receiver antenna, the transmitter circuit can then decrease the initial signal strength when modulating the RF signal. 
         [0043]    In some embodiments, the feedback mechanism can be a sensor (e.g., optical sensor, a temperature sensor, humidity sensor, or pressure sensor) that estimates, at a low resolution (e.g., lower than what the void fraction monitor can estimate), the void fraction of the two-phase mixture. This feedback mechanism enables the transmitter circuit to increase the power when the two-phase mixture has more liquid than vapor and decrease the power when the two-phase mixture has more vapor than liquid. 
         [0044]    At step  308 , the receiver circuit sends the attenuation measurements to the computing system. Based on at least the attenuation measurements, the known distance between the transmitter antenna and the receiver antenna, and/or the normalization parameters, the computing system can estimate a void fraction of the two-phase mixture. In some embodiments, the computing system can estimate the void fraction based on a moving average of the attenuation measurements. 
         [0045]    At step  310 , the computing system can compute enthalpy in the two-phase mixture based on the void fraction. At step  312 , the computing system can generate a heat variation timeline and/or a heat map to present to an operator of the geothermal power plant. At step  314 , the computing system can dynamically adjust parameters, such as the steam field, of the geothermal power plant based on the computed enthalpy. 
         [0046]    While processes or methods are presented in a given order, alternative embodiments may perform routines having steps, or employ systems having blocks, in a different order, and some processes or blocks may be deleted, moved, added, subdivided, combined, and/or modified to provide alternative or subcombinations. Each of these processes or blocks may be implemented in a variety of different ways. In addition, while processes or blocks are at times shown as being performed in series, these processes or blocks may instead be performed in parallel, or may be performed at different times. 
         [0047]      FIG. 4  is a block diagram of an example of a computing device  400 , which may represent one or more computing device or server described herein, in accordance with various embodiments. The computing device  400  can be one or more computing devices that implement the void fraction monitor  200  of  FIG. 2  or methods and processes described in this disclosure. The computing device  400  includes one or more processors  410  and memory  420  coupled to an interconnect  430 . The interconnect  430  shown in  FIG. 4  is an abstraction that represents any one or more separate physical buses, point-to-point connections, or both connected by appropriate bridges, adapters, or controllers. The interconnect  430 , therefore, may include, for example, a system bus, a Peripheral Component Interconnect (PCI) bus or PCI-Express bus, a HyperTransport or industry standard architecture (ISA) bus, a small computer system interface (SCSI) bus, a universal serial bus (USB), IIC (I2C) bus, or an Institute of Electrical and Electronics Engineers (IEEE) standard 1494 bus, also called “Firewire”. 
         [0048]    The processor(s)  410  is/are the central processing unit (CPU) of the computing device  400  and thus controls the overall operation of the computing device  400 . In certain embodiments, the processor(s)  410  accomplishes this by executing software or firmware stored in memory  420 . The processor(s)  410  may be, or may include, one or more programmable general-purpose or special-purpose microprocessors, digital signal processors (DSPs), programmable controllers, application specific integrated circuits (ASICs), programmable logic devices (PLDs), trusted platform modules (TPMs), or the like, or a combination of such devices. 
         [0049]    The memory  420  is or includes the main memory of the computing device  400 . The memory  420  represents any form of random access memory (RAM), read-only memory (ROM), flash memory, or the like, or a combination of such devices. In use, the memory  420  may contain a code  470  containing instructions according to the mesh connection system disclosed herein. 
         [0050]    Also connected to the processor(s)  410  through the interconnect  430  are a network adapter  440  and a storage adapter  450 . The network adapter  440  provides the computing device  400  with the ability to communicate with remote devices, over a network and may be, for example, an Ethernet adapter or Fibre Channel adapter. The network adapter  440  may also provide the computing device  400  with the ability to communicate with other computers. The storage adapter  450  enables the computing device  400  to access a persistent storage, and may be, for example, a Fibre Channel adapter or SCSI adapter. 
         [0051]    The code  470  stored in memory  420  may be implemented as software and/or firmware to program the processor(s)  410  to carry out actions described above. In certain embodiments, such software or firmware may be initially provided to the computing device  400  by downloading it from a remote system through the computing device  400  (e.g., via network adapter  440 ). 
         [0052]    The techniques introduced herein can be implemented by, for example, programmable circuitry (e.g., one or more microprocessors) programmed with software and/or firmware, or entirely in special-purpose hardwired circuitry, or in a combination of such forms. Special-purpose hardwired circuitry may be in the form of, for example, one or more application-specific integrated circuits (ASICs), programmable logic devices (PLDs), field-programmable gate arrays (FPGAs), etc. 
         [0053]    Software or firmware for use in implementing the techniques introduced here may be stored on a machine-readable storage medium and may be executed by one or more general-purpose or special-purpose programmable microprocessors. A “machine-readable storage medium,” as the term is used herein, includes any mechanism that can store information in a form accessible by a machine (a machine may be, for example, a computer, network device, cellular phone, personal digital assistant (PDA), manufacturing tool, any device with one or more processors, etc.). For example, a machine-accessible storage medium includes recordable/non-recordable media (e.g., read-only memory (ROM); random access memory (RAM); magnetic disk storage media; optical storage media; flash memory devices; etc.), etc. 
         [0054]    The term “logic,” as used herein, can include, for example, programmable circuitry programmed with specific software and/or firmware, special-purpose hardwired circuitry, or a combination thereof. 
         [0055]    Some embodiments of the disclosure have other aspects, elements, features, and steps in addition to or in place of what is described above. These potential additions and replacements are described throughout the rest of the specification.