Geothermal Energy Systems Overview
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Questions and Answers

What does the mass balance equation for the turbine indicate about the mass flow rate into and out of the system?

  • The mass flow rates into the turbine must be equal for proper operation.
  • The total mass flow rate into the turbine equals the total mass flow rate out. (correct)
  • The mass flow rate out is greater than the mass flow rate in.
  • The mass flow rate into the turbine is irrelevant for energy generation.

    • In the energy balance equation for the condenser, which of the following is essential for it to function correctly?

  • The energy flow out must equal the energy flow in plus heat added.
  • The heat absorbed must exceed the heat released.
  • The energy generated must be maximized without regard to flow rates.
  • The mass flow rates must be equal on both sides of the equation. (correct)

    • Which statement best describes the role of exergy efficiency in a geothermal system?

  • It accounts for the quality of energy and how much is lost to irreversibilities. (correct)
  • It only considers mass flow rates in energy calculations.
  • It measures the total energy output compared to input without considering losses.
  • It is irrelevant in assessing the performance of geothermal plants.

    • What is the primary function of the reinjection system in a geothermal power plant?

    <p>To maintain reservoir pressure and sustainability of the resource.</p> Signup and view all the answers

    Which energy balance equation correctly represents the relationship in Flash Chamber 1?

    <p>ṁ 7 = ṁ 8 + ṁ 9</p> Signup and view all the answers

    What does the MBE for the flash chamber represent?

    <p>The mass flow rates into and out of the system are equal.</p> Signup and view all the answers

    How is exergy efficiency for a turbine defined?

    <p>The ratio of useful work output to the energy input.</p> Signup and view all the answers

    What role does a separator play in a flash-steam power plant?

    <p>To divide the steam from the liquid phase before expansion.</p> Signup and view all the answers

    In the context of a condenser, what is the primary balance equation (MBE)?

    <p>Incoming mass flow equals outgoing mass flow.</p> Signup and view all the answers

    What impact does reinjection have on the energy efficiency of a geothermal power plant?

    <p>It improves the sustainability of the geothermal resource.</p> Signup and view all the answers

    Which equation represents the energy balance equation for the turbine phase?

    <p>ṁ 4 h4 = ṁ 5 h5 + Ẇ T1</p> Signup and view all the answers

    What is a key feature of single-flash steam power plants?

    <p>They produce electricity from high-pressure liquid through flashing.</p> Signup and view all the answers

    What is the function of the energy balance equation (EBE) in the separator?

    <p>To ensure energy conservation during phase change.</p> Signup and view all the answers

    What does the EnBE for the flash chamber indicate?

    <p>The generated entropy contributes to overall system efficiency.</p> Signup and view all the answers

    What is the approximate temperature increase of rock for every 100 m below ground level?

    <p>3ºC</p> Signup and view all the answers

    Which of the following represents an application of geothermal energy?

    <p>Aqua heating in spas</p> Signup and view all the answers

    What method is NOT commonly used for geothermal power generation?

    <p>Solar thermal power generation</p> Signup and view all the answers

    What is one of the main advantages of geothermal energy?

    <p>It is renewable and reliable.</p> Signup and view all the answers

    How can geothermal energy be used in agricultural production?

    <p>For heating greenhouses</p> Signup and view all the answers

    What is a key advantage of using a double-flash steam power plant over a single flash steam power plant?

    <p>It produces 10-20% more power.</p> Signup and view all the answers

    In the flashing process, what does the condition $x_1 = 0$ signify?

    <p>The fluid is completely in the liquid state.</p> Signup and view all the answers

    What happens to the remaining hot fluid after the first flashing stage in a double-flash steam power plant?

    <p>It undergoes a second flashing to produce lower pressure steam.</p> Signup and view all the answers

    Which equation represents the exergy efficiency of the turbine in a double-flash steam power plant?

    <p>$ rac{m_1 e_1}{m_1 e_1 - m_8 e_8}$</p> Signup and view all the answers

    What is indicated by the relationship $m_1 = m_2$ in the flashing process?

    <p>The total mass is conserved.</p> Signup and view all the answers

    How is the energy efficiency of a geothermal power plant with reinjection expressed mathematically?

    <p>$ rac{Ẇ_T}{ṁ_1 h_1 - ṁ_8 h_8}$</p> Signup and view all the answers

    Which equation accurately represents the energy balance equation (EBE) for the turbine phase?

    <p>$ṁ_4 h_4 = ṁ_5 h_5 + Ẇ_T$</p> Signup and view all the answers

    What is the role of the separator in a single-flash steam power plant?

    <p>To separate steam from liquid for energy extraction</p> Signup and view all the answers

    In the context of energy balances, what does the term $Ṡ_{gen,FC}$ in the flash chamber's energy balance equation denote?

    <p>Total entropy generated in the system</p> Signup and view all the answers

    How does the absence of reinjection affect the energy efficiency of a geothermal power plant?

    <p>It severely decreases energy efficiency due to loss of heat</p> Signup and view all the answers

    Study Notes

    Geothermal Energy Systems

    • Geothermal energy is derived from Earth's internal heat.
    • Geothermal resources are characterized by temperature ranges.
    • High-temperature sources (>220°C) are suitable for power generation.
    • Moderate-temperature sources (100-220°C) are used for direct applications like heating.
    • Low-temperature sources (50-150°C) are best for geothermal heat pumps.

    Geothermal Resources and Applications

    • Direct-use applications for geothermal resources include a range of industrial, agricultural, and domestic processes.
    • Geothermal energy systems use different technologies depending on the temperature of the geothermal resource.
    • Flash steam, combined flash and binary cycle, direct fluid use, heat exchangers, and heat pumps are common technologies.

    Geothermal Power Generation

    • Five common methods exist for geothermal power generation:
      • Direct steam (dry steam) power generation
      • Flash-steam power generation
      • Binary cycle power generation
      • Flash binary power generation
      • Combined geothermal power generation
    • Geothermal power plants use different technologies depending on the temperature of the geothermal resource.

    Geothermal Maps of Canada

    • Maps show the distribution of geothermal resources in Canada.
    • Different regions display different potential for geothermal use.
    • Some are high-temperature areas suitable for power generation.
    • Others are more suitable for direct use applications or ground source heat pumps.

    Geothermal Energy Use

    • The United States is a leading producer of geothermal electricity.
    • Top 10 countries (2023) for installed geothermal capacity are listed.
    • Total installed geothermal capacity is ~16,335 MW.
    • This data points to significance of geothermal capacity vs. potential use regions.

    Geothermal/Ground Source Heat Pumps

    • Geothermal/ground source heat pumps exploit constant temperature of the earth.
    • These systems are used in heating and cooling applications.
    • Ground source heat pumps are frequently used in building applications, and the use of this technology is projected to grow due to environmental and economic concerns.

    Case Studies

    • Case Studies include specific examples of geothermal energy use.
    • Examples of integrated systems, power plant designs, and multiple applications are detailed in this section.

    Closing Remarks

    • Geothermal energy is viewed as a renewable and environmentally friendly alternative.
    • Multiple applications and systems are cost-effective.
    • Geothermal energy is suitable for many use cases.

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    Related Documents

    Geothermal Energy Systems (PDF)

    Description

    Explore the fascinating world of geothermal energy through this quiz. Learn about the different temperature ranges, applications, and technologies used in geothermal systems for power generation. Test your knowledge on how geothermal energy can be harnessed for various applications.

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