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Questions and Answers
What is the typical operating temperature of a Solid Oxide Fuel Cell (SOFC)?
What is the typical operating temperature of a Solid Oxide Fuel Cell (SOFC)?
Which type of fuel cell is commonly used in portable electronic devices and small power systems?
Which type of fuel cell is commonly used in portable electronic devices and small power systems?
What is the main advantage of Hot Dry Rock (HDR) systems over traditional geothermal resources?
What is the main advantage of Hot Dry Rock (HDR) systems over traditional geothermal resources?
What is the primary concern related to the use of Hot Dry Rock (HDR) systems?
What is the primary concern related to the use of Hot Dry Rock (HDR) systems?
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Which type of fuel cell is used in fuel cell vehicles (FCVs) and buses as a clean alternative to traditional internal combustion engines?
Which type of fuel cell is used in fuel cell vehicles (FCVs) and buses as a clean alternative to traditional internal combustion engines?
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What is the primary purpose of hydraulic fracturing in the Hot Dry Rock (HDR) system?
What is the primary purpose of hydraulic fracturing in the Hot Dry Rock (HDR) system?
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Which type of fuel cell is commonly used in stationary power plants, offering high efficiency?
Which type of fuel cell is commonly used in stationary power plants, offering high efficiency?
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What is the primary purpose of fuel cells in backup power systems?
What is the primary purpose of fuel cells in backup power systems?
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What is the primary application of hot geothermal fluid in the total flow concept?
What is the primary application of hot geothermal fluid in the total flow concept?
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What is a key factor in selecting the appropriate technology for harnessing geothermal energy?
What is a key factor in selecting the appropriate technology for harnessing geothermal energy?
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What is the main advantage of using the total flow concept in geothermal projects?
What is the main advantage of using the total flow concept in geothermal projects?
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What is the sequence of operations in the total flow concept?
What is the sequence of operations in the total flow concept?
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What is the purpose of using binary cycle systems in geothermal energy production?
What is the purpose of using binary cycle systems in geothermal energy production?
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What is a characteristic of geothermal projects that adopt the total flow concept?
What is a characteristic of geothermal projects that adopt the total flow concept?
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What is the relationship between the geothermal resource and the desired applications?
What is the relationship between the geothermal resource and the desired applications?
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What is the benefit of using the total flow concept in geothermal energy production?
What is the benefit of using the total flow concept in geothermal energy production?
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What is the key component in a solar PV cell?
What is the key component in a solar PV cell?
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What is the main principle behind solar photovoltaic cells?
What is the main principle behind solar photovoltaic cells?
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What creates regions with excess electrons and regions with electron deficiencies in a solar PV cell?
What creates regions with excess electrons and regions with electron deficiencies in a solar PV cell?
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What excites the electrons in the semiconductor material of a solar PV cell?
What excites the electrons in the semiconductor material of a solar PV cell?
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What are the metal contacts placed on in a solar PV cell?
What are the metal contacts placed on in a solar PV cell?
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What does the anti-reflective coating applied to a solar PV cell do?
What does the anti-reflective coating applied to a solar PV cell do?
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What does doping a semiconductor material do in the context of solar PV cells?
What does doping a semiconductor material do in the context of solar PV cells?
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What is the purpose of the p-n junction in a solar PV cell?
What is the purpose of the p-n junction in a solar PV cell?
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What is the purpose of encapsulating a solar cell with a protective material?
What is the purpose of encapsulating a solar cell with a protective material?
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What happens when photons strike the semiconductor material in a solar cell?
What happens when photons strike the semiconductor material in a solar cell?
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What is the major cause of a decrease in solar cell efficiency as the temperature rises?
What is the major cause of a decrease in solar cell efficiency as the temperature rises?
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Why can't electrons pass through the electrolyte in a fuel cell?
Why can't electrons pass through the electrolyte in a fuel cell?
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Which fuel cell type operates at high temperatures using molten carbonate salts as the electrolyte?
Which fuel cell type operates at high temperatures using molten carbonate salts as the electrolyte?
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What happens at the cathode of a fuel cell during electricity generation?
What happens at the cathode of a fuel cell during electricity generation?
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How is the electricity outputted in a fuel cell produced?
How is the electricity outputted in a fuel cell produced?
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What is the role of metal contacts in a solar cell?
What is the role of metal contacts in a solar cell?
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What is the primary application of vapor-dominated geothermal systems?
What is the primary application of vapor-dominated geothermal systems?
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Which type of geothermal system involves passing hot geothermal fluid through a heat exchanger to vaporize a secondary binary fluid?
Which type of geothermal system involves passing hot geothermal fluid through a heat exchanger to vaporize a secondary binary fluid?
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In which geothermal system does a rapid pressure reduction lead to the creation of steam for electricity generation?
In which geothermal system does a rapid pressure reduction lead to the creation of steam for electricity generation?
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What is the characteristic of binary fluid systems that distinguishes them from other geothermal power generation methods?
What is the characteristic of binary fluid systems that distinguishes them from other geothermal power generation methods?
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What technology is utilized in both vapour-dominated and liquid-dominated reservoirs to create electricity through steam generation?
What technology is utilized in both vapour-dominated and liquid-dominated reservoirs to create electricity through steam generation?
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What makes combined heat and power (CHP) systems advantageous when integrated with HDR systems?
What makes combined heat and power (CHP) systems advantageous when integrated with HDR systems?
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Which geothermal system uses high-pressure hot water that is brought to the surface and rapidly reduced in pressure to generate electricity?
Which geothermal system uses high-pressure hot water that is brought to the surface and rapidly reduced in pressure to generate electricity?
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In what types of geothermal systems is hot water extracted and used directly for heating applications or electricity generation?
In what types of geothermal systems is hot water extracted and used directly for heating applications or electricity generation?
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Study Notes
Fuel Cells
- Solid Oxide Fuel Cell (SOFC):
- Operates at high temperatures (around 800-1,000°C)
- Suitable for stationary power generation and certain industrial applications
- Direct Methanol Fuel Cell (DMFC):
- Similar to PEMFC but uses liquid methanol as the fuel
- Commonly used in portable electronic devices and small power systems
- Phosphoric Acid Fuel Cell (PAFC):
- Uses phosphoric acid as the electrolyte
- Commonly used in stationary power plants, offering high efficiency
- Applications of Fuel Cells:
- Transportation: used in fuel cell vehicles (FCVs) and buses as a clean alternative to traditional internal combustion engines
- Stationary Power Generation: used to generate electricity for homes, businesses, and industries
- Backup Power Systems: provide reliable backup power for critical systems, such as data centers and hospitals
- Portable Power Systems: used in portable electronic devices like laptops and mobile phones
- Remote Power Systems: used in off-grid or remote locations to provide reliable and clean power
- Military Applications: used in military applications for power generation in remote locations, submarines, and unmanned vehicles
- Space Exploration: used in space missions to generate electricity on spacecraft
Geothermal Energy Resources
- Hot Dry Rock (HDR) system:
- Also known as Enhanced Geothermal Systems (EGS)
- Aims to harness heat from deep within the Earth's crust, particularly from areas where conventional geothermal resources are not readily available
- Principle of Operation:
- Drilling: deep wells are drilled into hot rock formations
- Hydraulic Fracturing: water is injected at high pressure into the wellbore to create fractures in the hot rocks
- Water Circulation and Heat Extraction: water is circulated through the created fractures, where it absorbs heat from the hot rock
- Advantages of HDR systems:
- Geographical flexibility: not limited to specific geological settings
- Scalability: have the potential for scalability, allowing for the development of larger and more powerful geothermal projects
- Resource expansion: can potentially expand the reach of geothermal resources to areas where conventional geothermal reservoirs are not present
Solar Photovoltaic (PV) Cells
- Principle:
- Convert sunlight directly into electricity
- Based on the photovoltaic effect, which is the generation of an electric current in a material when exposed to light
- Construction:
- Semiconductor material: typically made of silicon
- Doping: creates regions with excess electrons (n-type) and regions with a deficiency of electrons or "holes" (p-type)
- Metal contacts: placed on the top and bottom surfaces of the semiconductor to allow the flow of electrons
- Anti-reflective coating: applied on the top surface to minimize the reflection of sunlight and maximize light absorption
- Encapsulation: protects the semiconductor from environmental factors
- Working:
- Photovoltaic effect: frees electrons from their bound state, creating an electric field
- Electron movement: electrons move towards the n-type region, while holes created by the absorbed photons move towards the p-type region
- Generation of electricity: creates an electric current
- Conversion efficiency: measures how effectively a solar cell converts sunlight into usable electricity
- Influenced by various factors, including material quality, cell design, anti-reflective coating, temperature, and solar spectrum
Types of Geothermal Systems
- Vapor-Dominated Systems:
- Found in high-temperature reservoirs where the dominant phase is steam
- Steam is extracted directly from the reservoir and used to drive turbines for electricity generation
- Liquid-Dominated Systems:
- Found in reservoirs where water is the dominant phase, typically at moderate temperatures
- Water is extracted and used for its heat content rather than converting it into steam
- Flash Steam Systems:
- Applies to both vapour-dominated and liquid-dominated reservoirs
- Involves the extraction of high-pressure hot water from the reservoir, followed by a rapid reduction in pressure to create steam
- Binary Fluid Systems:
- Suitable for low- to moderate-temperature resources
- Utilizes a secondary (binary) fluid with a lower boiling point than water
- Total Flow Concept:
- Combines direct use and electricity generation in a single system
- Utilizes the total flow from a geothermal reservoir for various applications
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Description
Learn about the principle and construction of solar photovoltaic cells, including the photovoltaic effect and semiconductor materials used. Understand how sunlight is directly converted into electricity through the functioning of these cells.
