This document provides an overview of geothermal power plants. It discusses two main types - condensing power plants using reservoirs between 200-320°C, and binary fluid power plants using temperatures as low as 120°C. Issues encountered include scaling, erosion, and corrosion. Countermeasures involve separator and turbine maintenance, condenser material selection, and cooling system design. The document outlines components and typical problems in areas like the power house, controls, cooling towers, and re-injection systems.
This document summarizes an article from the International Journal of Mechanical Engineering and Technology that analyzes the performance of an oscillatory flow heat exchanger design for a hybrid solar water system. The study compares the performance of a commercial PV module versus a hybrid PV/T system with an oscillatory flow heat exchanger attached. Key findings include the hybrid system achieving a combined PV/T efficiency of 53.7% at a solar irradiance of 918 W/m2 and water flow rate of 0.035 kg/sec, representing an improvement over the commercial PV module alone. The hybrid system also achieved a higher PV module efficiency of 11.7% under these conditions due to cooling from the heat exchanger.
IJRET : International Journal of Research in Engineering and Technology is an international peer reviewed, online journal published by eSAT Publishing House for the enhancement of research in various disciplines of Engineering and Technology. The aim and scope of the journal is to provide an academic medium and an important reference for the advancement and dissemination of research results that support high-level learning, teaching and research in the fields of Engineering and Technology. We bring together Scientists, Academician, Field Engineers, Scholars and Students of related fields of Engineering and Technology
Phase Change Materials(PCM) based solar refrigerationVishvesh Shah
Topics to be Covered
Refrigeration Using solar Energy
Introduction
Solar PV Based Refrigeration
Solar Absorption Refrigeration
Energy Storage Systems
Battery
Phase Change Materials
Solar Refrigeration System Model Studies
Solar powered refrigerator with Thermal Energy Storage
Solar Direct Drive Refrigerator for Vaccine Storage
Improve energy efficiency for distillate hydrotreaters retrofit options hyd...Bhavesh kanani
This document discusses options for improving the energy efficiency of retrofitting distillate hydrotreaters. It examines increasing the surface area of feed preheat exchangers and installing a hot separator. Installing additional surface area in exchangers E-1 and E-3 through projects like adding twisted tubes recovers some heat but has a payback period of 4-14 years. Installing a hot separator that sends liquid directly to the stripper eliminates the need for exchanger E-3 and has better energy savings and payback around 3 years.
Experimental analysis of a flat plate solar collector with integrated latent heat thermal storage
*Mauricio, Carmona1, Mario Palacio2, ArnoldMartínez3
1 Mechanical Engineering Department, Universidad del Norte, Colombia
2 Faculty of Mechanical and Industrial Engineering, Universidad PontificiaBolivariana, Colombia
3 Mechanical Engineering Department, Universidad de Córdoba, Colombia
1E mail: mycarmona@uninorte.edu.co,2E mail: mario.palaciov@upb.edu.co
A B S T R A C T
In the present paper, an experimental analysis of a solar water heating collector with an integrated latent heat storage unit is presented. With the purpose to determine the performance of a device on a lab scale, but with commercial features, a flat plate solar collector with phase change material (PCM) containers under the absorber plate was constructed and tested. PCM used was a commercial semi-refined light paraffin with a melting point of 60°C. Tests were carried out in outdoor conditions from October 2016 to March 2017 starting at 7:00 AM until the collector does not transfer heat to the water after sunset. Performance variables as water inlet temperature, outlet temperature, mass flow and solar radiation were measured in order to determine a useful heat and the collector efficiency. Furthermore, operating temperatures of the glass cover, air gap, absorber plate, and PCM containers are presented. Other external variables as ambient temperature, humidity and wind speed were measured with a weather station located next to the collector. The developed prototype reached an average thermal efficiency of 24.11% and a maximum outlet temperature of 50°C. Results indicate that the absorber plate reached the PCM melting point in few cases, this suggests that the use of a PCM with a lower melting point could be a potential strategy to increase thermal storage. A thermal analysis and conclusions of the device performance are discussed.
The document discusses solar refrigeration systems, including their theory, types (photovoltaic, solar mechanical, absorption), and applications. It describes how solar refrigeration works by using solar energy to power a vapor compression refrigeration cycle. Three main types are described: photovoltaic systems use solar panels to power a compressor, solar mechanical uses solar heat to power a Rankine cycle and generate mechanical energy, and absorption replaces compression with heat-powered absorption into a liquid. Solar refrigeration can provide off-grid refrigeration for food storage, vaccines, and more to address energy access issues.
Enhancement of the output power generated from a hybrid solar thermal systemeSAT Journals
Abstract This paper investigates the output power and increased the efficiency of a hybrid Photovoltaic/ Thermal (PV/T) modules through utilizing the heat generated from the surface of panels by one axial tracking of the hybrid PV/Tsystem by means of zenith angle and decreasing the heat generated from the PV modules by controlling the flow rate of the system. A comparison between theoretical and experimental work results for fixed and tracking PV/T hybrid system is presented. Comsol software package used to simulate the electromagnetic waves produced by the sun through solving Maxwell's equations in three dimensions and the sun irradiance is assumed to be Gaussian distribution across the twelve mourning hours. Beside that an experimental work is presented depending on the results conjured from the theoretical experience used in Comsol Multiphysics In the second part of the experimental work, one axial sun-tracking system is designed where the movement of a photo-voltaic module is controlled to follow the Sun’s radiation using a Data acquisition card (DAQ) unit. Finally an active cooling system is designed and conducted to cool the fixed and tracking modules at which an absorber system consists of copper pipe welded with aluminium plate is attached underneath the PV modules to allow water flowing below the modules. In addition to the above an electrical analysis for both systems are presented where I-V, P-V, power with 12 mourning hour’s and electrical efficiency. Beside that the thermal analysis for the fixed and tracking PV modules and the piping water are presented where the input, output temperatures, the total energy of heat losses and thermal efficiency are calculated. As a result, a significant enhancement in the total electrical efficiency is observed with acceptable increase in the output water temperature. Keywords: Cooling systems; DAQ; Hybrid; Comsol Multiphysics; Mat lab; Solid work; Lab view.…
This paper describes an experimental study of using the waste heat from a Panasonic Under-
Ceiling split room air - conditioner had a rated capacity of 3.51 kW (12,000 Btu/h). An under – ceiling
split type air conditioning for heating domestic water in private homes. Energy recovery improved the
performance, and the recovered energy could replace electricity completely for heating domestic water
use. An extra charge of refrigerant in the air-conditioner could prevent its compressor from over heating
during energy recovery. The experimental conducted on varies capacity of the range from 22.5 litres to
120 litres storage tank. Results show the water temperature increased lies in the range of 50 OC to 65
OC. It was found that, when the initial water temperature in the 22.5 litres storage tank 27 OC, the water
temperature reached 65 OC in 105 minutes. For 120 litres water, temperature increased from 27 OC to 62
OC,5 in 240 minutes.
This document summarizes an article from the International Journal of Mechanical Engineering and Technology that analyzes the performance of an oscillatory flow heat exchanger design for a hybrid solar water system. The study compares the performance of a commercial PV module versus a hybrid PV/T system with an oscillatory flow heat exchanger attached. Key findings include the hybrid system achieving a combined PV/T efficiency of 53.7% at a solar irradiance of 918 W/m2 and water flow rate of 0.035 kg/sec, representing an improvement over the commercial PV module alone. The hybrid system also achieved a higher PV module efficiency of 11.7% under these conditions due to cooling from the heat exchanger.
IJRET : International Journal of Research in Engineering and Technology is an international peer reviewed, online journal published by eSAT Publishing House for the enhancement of research in various disciplines of Engineering and Technology. The aim and scope of the journal is to provide an academic medium and an important reference for the advancement and dissemination of research results that support high-level learning, teaching and research in the fields of Engineering and Technology. We bring together Scientists, Academician, Field Engineers, Scholars and Students of related fields of Engineering and Technology
Phase Change Materials(PCM) based solar refrigerationVishvesh Shah
Topics to be Covered
Refrigeration Using solar Energy
Introduction
Solar PV Based Refrigeration
Solar Absorption Refrigeration
Energy Storage Systems
Battery
Phase Change Materials
Solar Refrigeration System Model Studies
Solar powered refrigerator with Thermal Energy Storage
Solar Direct Drive Refrigerator for Vaccine Storage
Improve energy efficiency for distillate hydrotreaters retrofit options hyd...Bhavesh kanani
This document discusses options for improving the energy efficiency of retrofitting distillate hydrotreaters. It examines increasing the surface area of feed preheat exchangers and installing a hot separator. Installing additional surface area in exchangers E-1 and E-3 through projects like adding twisted tubes recovers some heat but has a payback period of 4-14 years. Installing a hot separator that sends liquid directly to the stripper eliminates the need for exchanger E-3 and has better energy savings and payback around 3 years.
Experimental analysis of a flat plate solar collector with integrated latent heat thermal storage
*Mauricio, Carmona1, Mario Palacio2, ArnoldMartínez3
1 Mechanical Engineering Department, Universidad del Norte, Colombia
2 Faculty of Mechanical and Industrial Engineering, Universidad PontificiaBolivariana, Colombia
3 Mechanical Engineering Department, Universidad de Córdoba, Colombia
1E mail: mycarmona@uninorte.edu.co,2E mail: mario.palaciov@upb.edu.co
A B S T R A C T
In the present paper, an experimental analysis of a solar water heating collector with an integrated latent heat storage unit is presented. With the purpose to determine the performance of a device on a lab scale, but with commercial features, a flat plate solar collector with phase change material (PCM) containers under the absorber plate was constructed and tested. PCM used was a commercial semi-refined light paraffin with a melting point of 60°C. Tests were carried out in outdoor conditions from October 2016 to March 2017 starting at 7:00 AM until the collector does not transfer heat to the water after sunset. Performance variables as water inlet temperature, outlet temperature, mass flow and solar radiation were measured in order to determine a useful heat and the collector efficiency. Furthermore, operating temperatures of the glass cover, air gap, absorber plate, and PCM containers are presented. Other external variables as ambient temperature, humidity and wind speed were measured with a weather station located next to the collector. The developed prototype reached an average thermal efficiency of 24.11% and a maximum outlet temperature of 50°C. Results indicate that the absorber plate reached the PCM melting point in few cases, this suggests that the use of a PCM with a lower melting point could be a potential strategy to increase thermal storage. A thermal analysis and conclusions of the device performance are discussed.
The document discusses solar refrigeration systems, including their theory, types (photovoltaic, solar mechanical, absorption), and applications. It describes how solar refrigeration works by using solar energy to power a vapor compression refrigeration cycle. Three main types are described: photovoltaic systems use solar panels to power a compressor, solar mechanical uses solar heat to power a Rankine cycle and generate mechanical energy, and absorption replaces compression with heat-powered absorption into a liquid. Solar refrigeration can provide off-grid refrigeration for food storage, vaccines, and more to address energy access issues.
Enhancement of the output power generated from a hybrid solar thermal systemeSAT Journals
Abstract This paper investigates the output power and increased the efficiency of a hybrid Photovoltaic/ Thermal (PV/T) modules through utilizing the heat generated from the surface of panels by one axial tracking of the hybrid PV/Tsystem by means of zenith angle and decreasing the heat generated from the PV modules by controlling the flow rate of the system. A comparison between theoretical and experimental work results for fixed and tracking PV/T hybrid system is presented. Comsol software package used to simulate the electromagnetic waves produced by the sun through solving Maxwell's equations in three dimensions and the sun irradiance is assumed to be Gaussian distribution across the twelve mourning hours. Beside that an experimental work is presented depending on the results conjured from the theoretical experience used in Comsol Multiphysics In the second part of the experimental work, one axial sun-tracking system is designed where the movement of a photo-voltaic module is controlled to follow the Sun’s radiation using a Data acquisition card (DAQ) unit. Finally an active cooling system is designed and conducted to cool the fixed and tracking modules at which an absorber system consists of copper pipe welded with aluminium plate is attached underneath the PV modules to allow water flowing below the modules. In addition to the above an electrical analysis for both systems are presented where I-V, P-V, power with 12 mourning hour’s and electrical efficiency. Beside that the thermal analysis for the fixed and tracking PV modules and the piping water are presented where the input, output temperatures, the total energy of heat losses and thermal efficiency are calculated. As a result, a significant enhancement in the total electrical efficiency is observed with acceptable increase in the output water temperature. Keywords: Cooling systems; DAQ; Hybrid; Comsol Multiphysics; Mat lab; Solid work; Lab view.…
This paper describes an experimental study of using the waste heat from a Panasonic Under-
Ceiling split room air - conditioner had a rated capacity of 3.51 kW (12,000 Btu/h). An under – ceiling
split type air conditioning for heating domestic water in private homes. Energy recovery improved the
performance, and the recovered energy could replace electricity completely for heating domestic water
use. An extra charge of refrigerant in the air-conditioner could prevent its compressor from over heating
during energy recovery. The experimental conducted on varies capacity of the range from 22.5 litres to
120 litres storage tank. Results show the water temperature increased lies in the range of 50 OC to 65
OC. It was found that, when the initial water temperature in the 22.5 litres storage tank 27 OC, the water
temperature reached 65 OC in 105 minutes. For 120 litres water, temperature increased from 27 OC to 62
OC,5 in 240 minutes.
1. The document discusses a study that modifies the design of an electro-thermal energy storage (ETES) system to integrate it with district heating and cooling networks. The goal is to utilize excess heat from the ETES cycles to provide useful heating and cooling services.
2. Two major design modifications are proposed - turbine intercooling and turbine bleeding. These allow the ETES system to balance irreversibilities by producing additional heating and cooling while storing electricity.
3. An economic evaluation calculates the marginal costs and average total costs of energy services from the integrated system under different operating conditions. As expected, the average total cost is found to continuously decrease for a monopolistic energy service firm.
This document is a thesis submitted by Ahmad Asyraf Bin Ramli in partial fulfillment of the requirements for a Bachelor of Mechanical Engineering degree from Universiti Malaysia Pahang in 2010. It presents a theoretical analysis of a solar water heating system, developing a mathematical model to analyze how the temperature changes based on factors like the area of the flat plate collector, volume of the insulated storage tank, piping size, and water flow rate. The analysis calculates the efficiency of the collector and storage tank for different sizes and volumes, as well as the solar fraction for different collector and tank sizes under varying temperature and flow conditions. The models provide data to optimize design for high capacity and facilitate future study.
This document proposes a novel latent heat storage system for solar space heating and cooling systems using refrigerant storage. The system utilizes an absorption refrigeration cycle using a heat source such as solar energy to generate refrigerant gas. The refrigerant is condensed and stored for later use, providing improved energy storage capacity over sensible heat storage methods. When heating or cooling is needed, the stored refrigerant is evaporated to power the cycle. For heating, the absorber heat is used to heat buildings. The refrigerant storage concept provides high energy density, near-ambient storage temperatures, and low storage pressures. This system could improve the viability of solar heating and cooling if extended for combined year-round operation.
IRJET- A Review on Thermal Analysis and Optimization of Heat Exchanger Design...IRJET Journal
This document discusses heat exchangers and their optimization for co-generation units. It begins with an abstract discussing heat exchangers and their uses. It then discusses key factors that influence heat exchanger efficiency such as temperature differential, flow rate, and installation configuration. Common heat exchanger materials are also discussed. The document then focuses on co-generation and discusses past studies on optimizing heat exchangers for co-generation units through variables like number of tubes, tube diameter, and inlet velocity. The present work aims to obtain the best heat exchanger design for co-generation units by comparing efficiency under different parameters.
thermo chemical energy storage system for solar plantsRajneesh Gautam
Thermochemical energy storage (TES) systems store energy through chemical reactions and have a higher energy density than sensible or latent heat storage. They involve dissociating a chemical into components during charging and reintegrating them during discharge. One example is an ammonia-based TES system for concentrating solar power plants. It uses the reversible dissociation of ammonia (NH3) into nitrogen (N2) and hydrogen (H2) gases. During charging, solar energy dissociates NH3, and the components are stored. During discharge, the gases recombine exothermically to regenerate NH3, releasing energy. Such chemical TES systems could provide baseload power but require more research on performance and costs
This document summarizes research on integrating phase change materials (PCMs) into solar water heating systems for thermal energy storage. It reviews five studies that examined using PCMs like paraffin wax, calcium chloride hexahydrate, and sodium thiosulfate pentahydrate. The performance enhancements of PCMs include storing up to 3.45 times more energy and maintaining hot water temperatures during off-sunshine hours through latent heat release. However, flow rate affects efficiency, with lower rates providing hot water longer. Increased PCM mass also lengthens storage time but lowers charging temperatures. Overall, PCMs improve solar water heating by enabling isothermal energy storage and release.
This document discusses different types of energy storage systems including superconducting magnetic energy storage (SMES), thermal energy storage (TES), and their applications. SMES stores energy in a superconducting coil's magnetic field and can quickly discharge stored energy back to the electric grid. TES temporarily stores thermal energy and can balance energy supply and demand. TES includes sensible heat storage using liquids, solids, or both, and latent heat storage using phase change materials. These storage systems provide benefits like clean power generation and mitigating renewable energy fluctuations.
THERMAL ANALYSIS AND DESIGN OF A NATURAL DRAFT COOLING TOWER OF A 1000 MW NUC...Sayeed Mohammed
This poster was presented at 2nd International Bose Conference, 2015, December 03-04, 2015, University of Dhaka
Abstract
Cooling towers use the principle of evaporative cooling to remove process heat from the cooling water and reduces its temperature to the wet-bulb air temperature. It is a heat and mass transfer device. This method of cooling provides with efficient and environment-friendly method of cooling particularly in locations where sufficient cooling water cannot be easily obtained from natural sources or where concern for the environment imposes some limits on the temperature at which cooling water can be returned to the surrounding. Cooling towers are an important part of the nuclear power plants which remove heat from coolant (water) of the condenser and recirculate it. Natural draft cooling towers represent a relatively inexpensive and dependable means of removing heat from cooling water as air inside it is circulated by natural convection, no mechanical means such as fans propellers are needed. The performance of the natural draft cooling tower is dominated by wind speed, ambient air temperatures and humidity in the atmospheric conditions. This paper provides the analysis of designing a natural draft cooling tower considering all these parameters with the help of trial and iterative method. The effect of height, diameter, and the type of filling material selected, are studied.
Utility companies generate electricity to meet fluctuating demand by using both base load and peak power stations. Base load stations operate continuously using cheaper fuels, while peak stations only operate during high demand periods and use more expensive fuels. Energy storage technologies allow excess energy, such as solar, to be stored and discharged later to better match supply with demand, reducing costs. Common storage methods include sensible heat storage using water, rocks or phase change materials, and thermochemical storage using chemical reactions.
Thermal energy storage systems store thermal energy and make it available at a later time for uses such as balancing energy supply and demand or shifting energy use from peak to off-peak hours. The document discusses several types of thermal energy storage including latent heat storage using phase change materials, sensible heat storage using temperature changes in materials, and thermo-chemical storage using chemical reactions. Case studies of thermal energy storage applications in solar plants, buildings, and cold chain transportation are also presented.
Sensible heat energy storage technology using low cost locally available ther...Husain Mehdi
Thermal energy storage in packed beds is increasing attention due to necessary component for efficient utilization of solar energy. A one dimensional thermal model for the behavior of a packed bed is presented for low cost thermal energy sensible heat energy storage materials (i.e. stone, glass, rocks, bricks, and granite) and air as the heat transfer fluid. This model predicts successfully during storage are presented for brick and rock in a cylindrical packed bed storage unit. Explicit expression for time variation of storage material temperature and air flowing in the system have been developed and performance parameters have been computed for five storage materials.
This document summarizes a senior design project to develop a cooling system for solar panels. The system aims to improve solar panel efficiency by preventing overheating. It uses flowing water within an insulated chamber behind the panels to conduct heat away. Testing showed the cooling system reduced panel temperatures by 16.9°C compared to an uncooled panel, increasing power output by 4%. While heat transfer to the water was lower than expected, the design demonstrates proof of concept. Potential improvements include using molded thermoplastics, adding insulation, and including fins to further transfer heat.
Experiment study of water based photovoltaic-thermal (PV/T) collectorIJECEIAES
Solar radiation can be converted to the electrical energy and thermal energy by photovoltaic panel and solar collector. In this experiment, PV/T collector was designed, fabricated and tested its performance. The experiment conducted on PV/T collector with water flow at mass flow rate 0.012 kg/s to 0.0255 kg/s. The water flow with the stainless stell absorber help the PV/T collector in increasing the convection of thermal heat transfer. The power output increase with increase of radiation. The efficiency of PVT varies with different intensity of radiation which stated in this experiment for 750 W/m2 and 900 W/m2. The analysis of energy and exergy are excuted and results show energy output for water based PV/T collector are 346 W for solar radiation 700 W/m2 and 457 W for solar radiation 900 W/m2. Meanwhile the total exergy output compared to the PV panel without stainless stell absorber, which the exergy increased by 22.48% for 700 W/m2 and 20.87% for 900 W/m2.
A geothermal heating and cooling system uses a heat pump and underground pipes (loops) to extract or discharge heat from the earth to provide heating and cooling for buildings. There are two main types of loops - closed loops which circulate water or antifreeze through buried pipes to exchange heat with the ground without contaminating the external environment, and open loops which draw groundwater from wells. Vertical closed loops are common for commercial buildings, using U-shaped pipes in deep wells, while horizontal closed loops use parallel pipes in shallow trenches. Geothermal systems can also use pond loops or hybrid systems.
This presentation describes how use of judiciously selected Phase Change Materials can be used effectively to store energy and make it available when needed.
In a solar thermal application, typically sunlight is available in a 6-8 hour window from 8am to 4pm. However, the usage extends much beyond that. Phase Change Materials can be used to store energy for usage as required.
Novel technique for maximizing the thermal efficiency of a hybrid pveSAT Journals
Abstract In this paper a comparison between numerical model and experimental work results for a fixed Photovoltaic/ Thermal (PV/T) hybrid system is presented. The simulation in this work is based on a numerical model in solving the equations and determining the Photovoltaic (PV) cells thermal characteristics using both MATLAB and COMSOL Multiphysics. COMSOL is simulating the electromagnetic waves produced by the Sun through solving Maxwell's equations in three dimensions using Finite Elements Methods (FEM) and the sun irradiance is assumed to be Gaussian distribution across the twelve mourning hours. Beside that an experimental work is presented depending on the results conjured from the theoretical experience used in Comsol Multiphysics. A Pulse Width Modulator (PWM) is used to control the solenoid valve operation. In addition to the above a thermal analysis for the fixed PV modules and the piping water is presented where the output water temperatures, rate of heat transfer, overall heat transfer coefficient and thermal efficiency are calculated. As a result, a significant enhancement in the total thermal efficiency is observed with acceptable increase in the output water temperature. Keywords: Cooling systems; DAQ; Hybrid; COMSOL MULTIPHYSICS; MATLAB; Solid work; Lab view.
2013.10.18 alfred piggott gentherm nrel sae thermoelectric battery thermal ma...ap3slidshare
This document discusses using thermoelectric devices (TEDs) for distributed battery thermal management. It proposes integrating TEDs directly into battery bus bars to provide localized and individually controlled cooling of battery cells. Modeling shows TED-only cooling of 5 watts per cell can maintain a 10-year battery life. Future development testing will evaluate air-cooled TED concepts for battery thermal management and utilize a simplified drive cycle generating 3.5-5 watts of heat per cell. Thermoelectric battery thermal management could enable active cooling solutions for mild hybrid applications without liquid cooling loops.
DIRECT EXPANSION GROUND SOURCE HEAT PUMPS FOR HEATING AND COOLINGIJSIT Editor
This article is an introduction to the energy problem and the possible saving that can be achieved
through improving building performance and the use of ground energy sources. The relevance and
importance of the study is discussed in the paper, which, also, highlights the objectives of the study, and the
scope of the theme. This study discusses some of the current activity in the GSHPs field. The basic system and
several variations for buildings are presented along with examples of systems in operation. Finally, the GCHP
is presented as an alternative that is able to counter much of the criticism leveled by the natural gas industry
toward conventional heat pumps. Several advantages and disadvantages are listed. Operating and installation
costs are briefly discussed.
Thermal energy storage materials and systems for solar energy applicationsSivanjaneya Reddy
How to enhance thermal conductivity for phase change materials and selection of phase change material and about systems for solar energy application has been presented
This document discusses utilizing solar energy for facility cooling. Key points include:
- Solar cooling is useful in summer months or tropical regions due to increased solar energy availability and cooling demand. It requires only 20% of the power of conventional cooling.
- Solar plants match energy production to consumption profiles and reduce environmental impacts compared to conventional cooling through use of renewable energy and no CO2 emissions.
- Maintenance costs are lower for solar plants which have few moving parts and longer lifetimes (20-25 years) than conventional cooling systems. Cost savings also result from reduced energy costs over time.
- The document provides steps for properly assessing a facility's cooling load, available solar space, conversion methods, collector selection, system s
Early modes of communication included sending messages by birds and using fire signals. The postal system was developed with protocols for addressing letters, applying postage, and routing letters to their destinations via local and destination post offices. Modern communication involves various protocols at different layers, from the physical transmission of bits to the application content being transmitted. Protocols ensure devices and systems can effectively communicate according to shared standards.
The document provides information about the television standards and communication systems used at Doordarshan Kendra Patna from December 4th to December 24th, 2012. It discusses the PAL television standard used in India and describes PAL encoders and decoders. It also summarizes television principles such as scanning, cameras, color composite video signals, television studios, transmitters and more. The document was submitted in partial fulfillment of a Bachelor of Technology degree.
1. The document discusses a study that modifies the design of an electro-thermal energy storage (ETES) system to integrate it with district heating and cooling networks. The goal is to utilize excess heat from the ETES cycles to provide useful heating and cooling services.
2. Two major design modifications are proposed - turbine intercooling and turbine bleeding. These allow the ETES system to balance irreversibilities by producing additional heating and cooling while storing electricity.
3. An economic evaluation calculates the marginal costs and average total costs of energy services from the integrated system under different operating conditions. As expected, the average total cost is found to continuously decrease for a monopolistic energy service firm.
This document is a thesis submitted by Ahmad Asyraf Bin Ramli in partial fulfillment of the requirements for a Bachelor of Mechanical Engineering degree from Universiti Malaysia Pahang in 2010. It presents a theoretical analysis of a solar water heating system, developing a mathematical model to analyze how the temperature changes based on factors like the area of the flat plate collector, volume of the insulated storage tank, piping size, and water flow rate. The analysis calculates the efficiency of the collector and storage tank for different sizes and volumes, as well as the solar fraction for different collector and tank sizes under varying temperature and flow conditions. The models provide data to optimize design for high capacity and facilitate future study.
This document proposes a novel latent heat storage system for solar space heating and cooling systems using refrigerant storage. The system utilizes an absorption refrigeration cycle using a heat source such as solar energy to generate refrigerant gas. The refrigerant is condensed and stored for later use, providing improved energy storage capacity over sensible heat storage methods. When heating or cooling is needed, the stored refrigerant is evaporated to power the cycle. For heating, the absorber heat is used to heat buildings. The refrigerant storage concept provides high energy density, near-ambient storage temperatures, and low storage pressures. This system could improve the viability of solar heating and cooling if extended for combined year-round operation.
IRJET- A Review on Thermal Analysis and Optimization of Heat Exchanger Design...IRJET Journal
This document discusses heat exchangers and their optimization for co-generation units. It begins with an abstract discussing heat exchangers and their uses. It then discusses key factors that influence heat exchanger efficiency such as temperature differential, flow rate, and installation configuration. Common heat exchanger materials are also discussed. The document then focuses on co-generation and discusses past studies on optimizing heat exchangers for co-generation units through variables like number of tubes, tube diameter, and inlet velocity. The present work aims to obtain the best heat exchanger design for co-generation units by comparing efficiency under different parameters.
thermo chemical energy storage system for solar plantsRajneesh Gautam
Thermochemical energy storage (TES) systems store energy through chemical reactions and have a higher energy density than sensible or latent heat storage. They involve dissociating a chemical into components during charging and reintegrating them during discharge. One example is an ammonia-based TES system for concentrating solar power plants. It uses the reversible dissociation of ammonia (NH3) into nitrogen (N2) and hydrogen (H2) gases. During charging, solar energy dissociates NH3, and the components are stored. During discharge, the gases recombine exothermically to regenerate NH3, releasing energy. Such chemical TES systems could provide baseload power but require more research on performance and costs
This document summarizes research on integrating phase change materials (PCMs) into solar water heating systems for thermal energy storage. It reviews five studies that examined using PCMs like paraffin wax, calcium chloride hexahydrate, and sodium thiosulfate pentahydrate. The performance enhancements of PCMs include storing up to 3.45 times more energy and maintaining hot water temperatures during off-sunshine hours through latent heat release. However, flow rate affects efficiency, with lower rates providing hot water longer. Increased PCM mass also lengthens storage time but lowers charging temperatures. Overall, PCMs improve solar water heating by enabling isothermal energy storage and release.
This document discusses different types of energy storage systems including superconducting magnetic energy storage (SMES), thermal energy storage (TES), and their applications. SMES stores energy in a superconducting coil's magnetic field and can quickly discharge stored energy back to the electric grid. TES temporarily stores thermal energy and can balance energy supply and demand. TES includes sensible heat storage using liquids, solids, or both, and latent heat storage using phase change materials. These storage systems provide benefits like clean power generation and mitigating renewable energy fluctuations.
THERMAL ANALYSIS AND DESIGN OF A NATURAL DRAFT COOLING TOWER OF A 1000 MW NUC...Sayeed Mohammed
This poster was presented at 2nd International Bose Conference, 2015, December 03-04, 2015, University of Dhaka
Abstract
Cooling towers use the principle of evaporative cooling to remove process heat from the cooling water and reduces its temperature to the wet-bulb air temperature. It is a heat and mass transfer device. This method of cooling provides with efficient and environment-friendly method of cooling particularly in locations where sufficient cooling water cannot be easily obtained from natural sources or where concern for the environment imposes some limits on the temperature at which cooling water can be returned to the surrounding. Cooling towers are an important part of the nuclear power plants which remove heat from coolant (water) of the condenser and recirculate it. Natural draft cooling towers represent a relatively inexpensive and dependable means of removing heat from cooling water as air inside it is circulated by natural convection, no mechanical means such as fans propellers are needed. The performance of the natural draft cooling tower is dominated by wind speed, ambient air temperatures and humidity in the atmospheric conditions. This paper provides the analysis of designing a natural draft cooling tower considering all these parameters with the help of trial and iterative method. The effect of height, diameter, and the type of filling material selected, are studied.
Utility companies generate electricity to meet fluctuating demand by using both base load and peak power stations. Base load stations operate continuously using cheaper fuels, while peak stations only operate during high demand periods and use more expensive fuels. Energy storage technologies allow excess energy, such as solar, to be stored and discharged later to better match supply with demand, reducing costs. Common storage methods include sensible heat storage using water, rocks or phase change materials, and thermochemical storage using chemical reactions.
Thermal energy storage systems store thermal energy and make it available at a later time for uses such as balancing energy supply and demand or shifting energy use from peak to off-peak hours. The document discusses several types of thermal energy storage including latent heat storage using phase change materials, sensible heat storage using temperature changes in materials, and thermo-chemical storage using chemical reactions. Case studies of thermal energy storage applications in solar plants, buildings, and cold chain transportation are also presented.
Sensible heat energy storage technology using low cost locally available ther...Husain Mehdi
Thermal energy storage in packed beds is increasing attention due to necessary component for efficient utilization of solar energy. A one dimensional thermal model for the behavior of a packed bed is presented for low cost thermal energy sensible heat energy storage materials (i.e. stone, glass, rocks, bricks, and granite) and air as the heat transfer fluid. This model predicts successfully during storage are presented for brick and rock in a cylindrical packed bed storage unit. Explicit expression for time variation of storage material temperature and air flowing in the system have been developed and performance parameters have been computed for five storage materials.
This document summarizes a senior design project to develop a cooling system for solar panels. The system aims to improve solar panel efficiency by preventing overheating. It uses flowing water within an insulated chamber behind the panels to conduct heat away. Testing showed the cooling system reduced panel temperatures by 16.9°C compared to an uncooled panel, increasing power output by 4%. While heat transfer to the water was lower than expected, the design demonstrates proof of concept. Potential improvements include using molded thermoplastics, adding insulation, and including fins to further transfer heat.
Experiment study of water based photovoltaic-thermal (PV/T) collectorIJECEIAES
Solar radiation can be converted to the electrical energy and thermal energy by photovoltaic panel and solar collector. In this experiment, PV/T collector was designed, fabricated and tested its performance. The experiment conducted on PV/T collector with water flow at mass flow rate 0.012 kg/s to 0.0255 kg/s. The water flow with the stainless stell absorber help the PV/T collector in increasing the convection of thermal heat transfer. The power output increase with increase of radiation. The efficiency of PVT varies with different intensity of radiation which stated in this experiment for 750 W/m2 and 900 W/m2. The analysis of energy and exergy are excuted and results show energy output for water based PV/T collector are 346 W for solar radiation 700 W/m2 and 457 W for solar radiation 900 W/m2. Meanwhile the total exergy output compared to the PV panel without stainless stell absorber, which the exergy increased by 22.48% for 700 W/m2 and 20.87% for 900 W/m2.
A geothermal heating and cooling system uses a heat pump and underground pipes (loops) to extract or discharge heat from the earth to provide heating and cooling for buildings. There are two main types of loops - closed loops which circulate water or antifreeze through buried pipes to exchange heat with the ground without contaminating the external environment, and open loops which draw groundwater from wells. Vertical closed loops are common for commercial buildings, using U-shaped pipes in deep wells, while horizontal closed loops use parallel pipes in shallow trenches. Geothermal systems can also use pond loops or hybrid systems.
This presentation describes how use of judiciously selected Phase Change Materials can be used effectively to store energy and make it available when needed.
In a solar thermal application, typically sunlight is available in a 6-8 hour window from 8am to 4pm. However, the usage extends much beyond that. Phase Change Materials can be used to store energy for usage as required.
Novel technique for maximizing the thermal efficiency of a hybrid pveSAT Journals
Abstract In this paper a comparison between numerical model and experimental work results for a fixed Photovoltaic/ Thermal (PV/T) hybrid system is presented. The simulation in this work is based on a numerical model in solving the equations and determining the Photovoltaic (PV) cells thermal characteristics using both MATLAB and COMSOL Multiphysics. COMSOL is simulating the electromagnetic waves produced by the Sun through solving Maxwell's equations in three dimensions using Finite Elements Methods (FEM) and the sun irradiance is assumed to be Gaussian distribution across the twelve mourning hours. Beside that an experimental work is presented depending on the results conjured from the theoretical experience used in Comsol Multiphysics. A Pulse Width Modulator (PWM) is used to control the solenoid valve operation. In addition to the above a thermal analysis for the fixed PV modules and the piping water is presented where the output water temperatures, rate of heat transfer, overall heat transfer coefficient and thermal efficiency are calculated. As a result, a significant enhancement in the total thermal efficiency is observed with acceptable increase in the output water temperature. Keywords: Cooling systems; DAQ; Hybrid; COMSOL MULTIPHYSICS; MATLAB; Solid work; Lab view.
2013.10.18 alfred piggott gentherm nrel sae thermoelectric battery thermal ma...ap3slidshare
This document discusses using thermoelectric devices (TEDs) for distributed battery thermal management. It proposes integrating TEDs directly into battery bus bars to provide localized and individually controlled cooling of battery cells. Modeling shows TED-only cooling of 5 watts per cell can maintain a 10-year battery life. Future development testing will evaluate air-cooled TED concepts for battery thermal management and utilize a simplified drive cycle generating 3.5-5 watts of heat per cell. Thermoelectric battery thermal management could enable active cooling solutions for mild hybrid applications without liquid cooling loops.
DIRECT EXPANSION GROUND SOURCE HEAT PUMPS FOR HEATING AND COOLINGIJSIT Editor
This article is an introduction to the energy problem and the possible saving that can be achieved
through improving building performance and the use of ground energy sources. The relevance and
importance of the study is discussed in the paper, which, also, highlights the objectives of the study, and the
scope of the theme. This study discusses some of the current activity in the GSHPs field. The basic system and
several variations for buildings are presented along with examples of systems in operation. Finally, the GCHP
is presented as an alternative that is able to counter much of the criticism leveled by the natural gas industry
toward conventional heat pumps. Several advantages and disadvantages are listed. Operating and installation
costs are briefly discussed.
Thermal energy storage materials and systems for solar energy applicationsSivanjaneya Reddy
How to enhance thermal conductivity for phase change materials and selection of phase change material and about systems for solar energy application has been presented
This document discusses utilizing solar energy for facility cooling. Key points include:
- Solar cooling is useful in summer months or tropical regions due to increased solar energy availability and cooling demand. It requires only 20% of the power of conventional cooling.
- Solar plants match energy production to consumption profiles and reduce environmental impacts compared to conventional cooling through use of renewable energy and no CO2 emissions.
- Maintenance costs are lower for solar plants which have few moving parts and longer lifetimes (20-25 years) than conventional cooling systems. Cost savings also result from reduced energy costs over time.
- The document provides steps for properly assessing a facility's cooling load, available solar space, conversion methods, collector selection, system s
Early modes of communication included sending messages by birds and using fire signals. The postal system was developed with protocols for addressing letters, applying postage, and routing letters to their destinations via local and destination post offices. Modern communication involves various protocols at different layers, from the physical transmission of bits to the application content being transmitted. Protocols ensure devices and systems can effectively communicate according to shared standards.
The document provides information about the television standards and communication systems used at Doordarshan Kendra Patna from December 4th to December 24th, 2012. It discusses the PAL television standard used in India and describes PAL encoders and decoders. It also summarizes television principles such as scanning, cameras, color composite video signals, television studios, transmitters and more. The document was submitted in partial fulfillment of a Bachelor of Technology degree.
The document provides details about the design of a G+2 residential building structure located in Delhi for Swati Structure Solutions Pvt. Ltd. It includes information on the design loads as per Indian codes, analysis of the structure using STAAD Pro software, load calculations, seismic design criteria as per IS 1893, and design and detailing of reinforced concrete structural elements. The structure will consist of a column-beam-slab framing system to resist vertical and lateral loads.
This document discusses a mini project on a four bar linkage mechanism. A four bar linkage consists of four links connected by four pin joints to form a quadrilateral. It includes a fixed link, connecting link, crank link, and rocker link. The crank rotates due to the rotation of a driving wheel and transmits motion to the connecting rod. The connecting rod then transmits oscillating motion to the rocker arm. Four bar linkages have many applications such as in deep boring machines, locomotives, hand pumps, and lathes.
The document provides information on load reduction factors according to ACI code section 9.3 for different structural members. It also provides design steps and calculations for an under reinforced steel beam and a reinforced concrete footing. Additionally, it discusses pre-stressed concrete and losses of pre-stressing such as elastic shortening, creep, shrinkage, steel relaxation, anchorage slip, frictional loss, and bending of member.
India faces many environmental challenges including loss of forest cover and biodiversity, water scarcity, air and water pollution, soil degradation, and unsustainable waste management. Specific issues discussed include the country's ranking high globally for river erosion, open defecation, and population growth reducing available fresh water. Agricultural practices have also reduced soil organic content and replaced more nutritious coarse grains with water-intensive rice and wheat. Loss of access to common property resources like forests and grazing lands further threatens the environment and livelihoods.
Doordarshan is India's largest public service broadcaster. It started television services in Delhi in 1959 and uses the PAL television standard with 625 horizontal lines and 50 vertical lines. A television studio contains areas for filming as well as production and control rooms for broadcasting programs. Key components include cameras, video tape recorders, character generators, and an earth station for transmitting signals to satellites. Signals are then broadcast from transmitters via antennas to satellites and received by viewers.
This document provides a summary of an implant training conducted by three students - Abhay Anand, Abhishek Prasad, and Argha Das - at BSNL, Patna from December 5, 2011 to December 30, 2011. The training covered topics such as company profile of BSNL, introduction to telecommunications technologies including exchanges, local and trunk lines, PCM, fibre optics, mobile communications, internet and broadband. The document includes sections on acknowledgements and contents covering the various topics studied during the training.
The document discusses several key factors regarding airport lighting, including different types of lights used for various purposes like approach lighting, runway lighting, taxiway lighting, and threshold lighting. It explains that airport lighting must be properly installed and maintained to guide pilots during night operations or low visibility conditions. Different lighting systems and patterns are used depending on the airport classification and level of air traffic. Standardization of airport lighting helps pilots navigate unfamiliar airports safely.
ELECTRICAL POWER GENERATION BY NON CONVENTIONAL ENERGY-GEOTHERMALJournal For Research
Geothermal energy has the potential to provide long-term, secure base-load energy and greenhouse gas (GHG) emissions reductions. Climate change is not expected to have any major impacts on the effectiveness of geothermal energy utilization, but the widespread deployment of geothermal energy could play a meaningful role in mitigating climate change and accessible geothermal energy from the Earth’s interior supplies heat for direct use and to generate electric energy. The paper deals with the use of geothermal resources for the production of electricity next are technologies of change geothermal energy into electrical energy, future of geothermal energy and advantage and disadvantage of geothermal energy
This document discusses several innovative power generation technologies for the future, including ocean thermal energy conversion (OTEC), biomass energy, and magneto-hydrodynamic (MHD) power generation. OTEC uses the temperature difference between warm surface waters and cold deep waters to power a turbine via a closed-cycle system using ammonia. Biomass energy generates power by burning organic materials like wood. MHD power generation directly converts the heat of fuels into electricity using ionized gases moving through powerful magnetic fields. The document concludes these new techniques can improve power generation efficiency to help address future power shortages.
To Improve Thermal Efficiency of 27mw Coal Fired Power PlantIJMER
Booming demand for electricity, especially in the developing countries, has raised power generation technologies in the headlines. At the same time the discussion about causes of global warming has focused on emissions originating from power generation and on CO2 reduction technologies such as:
(1) Alternative primary energy sources,
(2) Capture and storage of CO2,
(3) Increasing the efficiency of converting primary energy content into electricity.
In the dissertation, the thermal efficiency of the power plant is improved when Control of furnace draft (nearer to balanced draft). Oxygen level decreases percentage of flue gases. Above this level heat losses are increases & below this carbon mono-oxide is formed. Steam power plant is using fuel to generate electrical power. The used of the fuel must be efficient so the boiler can generate for the maximum electrical power. By the time the steam cycle in the boiler, it also had heat losses through some parts and it effect on the efficiency of the boiler. This project will analyze about the parts of losses and boiler efficiency. to find excess air which effect heat losses in boiler. By using the 27 MW coal fired thermal power plant of Birla Corporation Limited, Satna (M.P.) the data is collect by using types of Combustion & heat flow in boiler. Result of the analysis show that the efficiency of boiler depends on mass of coal burnt & type of combustion .This study is fulfilling the objective of analysis to find the boiler efficiency and heat losses in boiler for 27 MW thermal power plant of Birla Corporation Limited, Satna (M.P.)
Cogeneration systems produce both electricity and useful thermal energy in a single integrated system to improve efficiency. This document discusses cogeneration systems that use steam turbines, gas turbines, or reciprocating engines as the prime mover. Steam turbine cogeneration systems can be backpressure or extraction condensing configurations. Gas turbine cogeneration systems operate on the Brayton cycle of compressing, heating, and expanding air. Cogeneration provides benefits like increased efficiency, lower emissions, and cost savings compared to separate thermal and electrical systems.
This document discusses different types of power plants. It begins by describing thermal power plants, including their turbines and cooling towers. It then covers hydroelectric power plants, explaining pelton, reaction, kaplan and francis turbines. The document also examines nuclear power plants, outlining their basic layout and how nuclear reactors work. Additionally, it summarizes gas and diesel power plants. Finally, the document explores non-conventional power sources such as ocean thermal, wind, tidal, geothermal and magneto hydro dynamic systems.
Analysis of Induction Generator for Geothermal Power Generation Systemijtsrd
Nowadays, renewable energy sources contribute approximately twenty five percent of the world electricity supply. The challenge is the inevitable increase in energy consumption in the world with the risk of a major environmental impact and climate change as a results of the combustion of fossil fuels. Therefore, renewable energy has a very important role to play in the near future. Geothermal Power is one of the renewable energy sources, but it is largely ignored in favor of wind and solar energy. However, geothermal power is reliably predictable years in advance for power generation unlike wind and solar energy. Besides, it is convenient to supply the electricity sufficiently for rural and coastal areas which are far from national grid. The appropriate steam turbine to use in geothermal power plant is carefully selected. More importantly, the design calculation of a 0.5 MW, 6 poles induction generator is calculated in detail in order to generate electrical power concerned with the geothermal ranges of coastal areas in Myanmar. Geothermal power plant operations tend to be of three general kinds dry stream plants and flash plants, applied to high energy resources, and binary plants. Aung Myo Naing "Analysis of Induction Generator for Geothermal Power Generation System" Published in International Journal of Trend in Scientific Research and Development (ijtsrd), ISSN: 2456-6470, Volume-3 | Issue-5 , August 2019, URL: https://www.ijtsrd.com/papers/ijtsrd26756.pdf Paper URL: https://www.ijtsrd.com/engineering/electrical-engineering/26756/analysis-of-induction-generator-for--geothermal-power-generation-system/aung-myo-naing
This document provides an overview of different types of power plants including thermal, hydroelectric, nuclear, gas, diesel, and non-conventional power plants. It describes the basic components and working principles of each type of power plant. For hydroelectric plants specifically, it explains the key features and applications of Pelton wheels, reaction turbines, Kaplan turbines, and Francis turbines. The document also provides details on ocean thermal energy conversion, wind power, tidal power, geothermal energy, and magnetohydrodynamic power generation.
Energy and Exergy Analysis of a Cogeneration Cycle, Driven by Ocean Thermal E...theijes
Ocean Thermal Energy Conversion (OTEC) is a technology by which thermal energy from the ocean is harnessed and converted into electricity. It is one of the renewable energy technologies being researched into, as part of solutions to the challenge of global warming and climate change. A major setback of this technology, however, is that it has a very low cycle efficiency. In this work a cogeneration cycle is proposed which is driven by the temperature difference between the warm surface layer and the cold bottom layer of the ocean. The work is aimed at improving the overall cycle efficiency of OTEC systems by reducing the depth at which cold water is captured from the ocean. To achieve this, the cycle employs a binary mixture of ammonia and water as the working fluid and uses the mechanism of absorption to obtain the liquid phase of the working fluid after expansion through the turbine. The effects of varying cycle parameters such as the depth of cold-water capture, heat source temperature and mixture composition of the working fluid were investigated. With a basic solution mixture concentration of 0.40 kg/kg NH3/H2O, and under operating conditions of 30oC as the warm surface water temperature and a cold water temperature of 10oC, captured at a depth of 600m the proposed cycle produced a net power output of 42 kW, and a refrigeration capacity of 370 kW. The thermal efficiency computed was 1.94% and the exergy efficiency was 13.78%, both higher than the case where the depth of cold water capture was 1000m.
Realization of exhaust air recovery and waste heat recovery systems for energ...Alexander Decker
This document summarizes two energy recovery systems: exhaust air recovery and waste heat recovery. It describes how exhaust air from ventilation systems can be used to power small wind turbines to generate electricity. Experimental results show electricity generation of 190V and 230V at different air velocities. It also discusses using waste heat from air conditioning/chiller plants in a finned water tube boiler to warm water or produce steam, recovering some of the energy lost in exhaust gases. Both systems help convert wasted energy into useful energy and reduce carbon dioxide emissions through increased energy efficiency.
Solar air conditioning uses solar power through photovoltaic conversion of sunlight to electricity, geothermal cooling, or passive cooling methods. Photovoltaic systems can power conventional or absorption cooling systems for small residential or commercial buildings. Earth sheltering and cooling tubes can reduce cooling needs by taking advantage of stable underground temperatures. Geothermal heat pumps exchange heat with the ground through water circulating in closed loops to improve air conditioning efficiency. Passive solar techniques like building orientation and shading can reduce cooling loads through natural ventilation and heat transfer principles without active solar thermal systems.
The document describes binary cycle geothermal power plants and their operation. It discusses:
- Binary cycle power plants use a secondary working fluid to harness low and medium temperature geothermal resources, avoiding issues from contacting geothermal fluids directly.
- El Salvador operates two geothermal fields for power production, with one including a 9.2 MW binary plant using a heat exchanger to vaporize a working fluid like isopentane from geothermal brine.
- A basic binary plant consists of a preheater, evaporator, turbine, condenser, and pump, following a Rankine cycle to produce power from geothermal heat without mixing fluids.
The document discusses several key topics regarding distributed generation (DG) integration and microgrids:
1) It defines the differences between "integration" which encompasses economic and managerial aspects, and "interconnection" which refers only to the technological aspects.
2) It describes various DG technologies that can be used in microgrids like combined heat and power (CHP) systems, gas turbines, steam turbines, reciprocating engines, microturbines, and fuel cells.
3) It discusses important economic and managerial considerations for microgrid feasibility and viability, such as capacity optimization, demand management, and tariff mechanisms. Technical impacts of DG interconnection like voltage changes and protection challenges are also covered.
GENERATION OF POWER THROUGH HYDROGEN – OXYGEN FUEL CELLSinventy
This document summarizes a study that tested the ability of a hydrogen-oxygen fuel cell to generate electricity. The study used a small test rig to run experiments supplying hydrogen and oxygen gases to the fuel cell. The experiments measured voltage, current, power output, and other parameters over time. The results showed that the fuel cell was able to produce up to 13.44W of power at 11.20V by converting the chemical energy of hydrogen into electrical energy. Producing power from hydrogen in a fuel cell is presented as a clean and renewable alternative to fossil fuel-based power generation.
A Review On Thermal Energy Storage For Concentrating Solar Power PlantsSophia Diaz
The document reviews thermal energy storage technologies for concentrating solar power plants. It discusses several thermal energy storage systems including two-tank direct, two-tank indirect, and single tank thermocline systems. It also examines different types of thermal storage materials including sensible heat materials like molten salts, latent heat phase change materials, and chemical heat storage. Thermal energy storage can help overcome the intermittency of solar energy and reduce the levelized cost of energy for concentrating solar power plants.
This document discusses waste heat recovery through the use of a reverse refrigeration cycle or organic Rankine cycle (ORC). It begins by outlining the problem of inefficient production processes that lose a significant amount of heat. The document then provides an overview of how a reverse refrigeration cycle works using a lower boiling point fluid to convert low-temperature waste heat into electricity. It discusses some key components of the cycle like the evaporator, turbine, condenser and pump. The document outlines the methodology that will be used to analyze implementing a reverse refrigeration cycle for waste heat recovery, including specifying the problem, evaluating heat sources, selecting a working fluid, calculating the ideal cycle, sizing heat exchangers, and calculating the real cycle
HIGH TEMERATURE THERMAL ENERGY STOARAGE SYSTEM APPLICATIONSijiert bestjournal
Thermal energy storage (TES) includes a number of d ifferent technologies. Thermal energy can be stored at temperatures from -40�C to more than 400�C as sensi ble heat,latent heat and chemical energy (i.e. the rmo- chemical energy storage) using chemical reactions. Thermal energy storage in the form of sensible heat is based on the specific heat of a storage medium,whi ch is usually kept in storage tanks with high therm al insulation. The most popular and commercial heat st orage medium is water,which has a number of reside ntial and industrial applications. Underground storage of sensible heat in both liquid and solid media is al so used for typically large-scale applications. However,TES sy stems based on sensible heat storage offer a storag e capacity that is limited by the specific heat of th e storage medium. Phase change materials (PCMs) can offer a higher storage capacity that is associated with the latent heat of the phase change. PCMs also enable a target- oriented discharging temperature that is set by the constant temperature of the phase change. Thermo-c hemical storage (TCS) can offer even higher storage capacit ies. Thermo-chemical reactions (e.g. adsorption or the adhesion of a substance to the surface of another s olid or liquid) can be used to accumulate and disch arge heat and cold on demand (also regulating humidity) in a variety of applications using different chemical re actants. At present,
The document discusses magneto-hydrodynamic (MHD) power generation. It describes MHD generators that directly convert heat from ionized gases into electricity using magnetic fields. There are open-cycle and closed-cycle MHD systems. Open-cycle systems use gases once and then discharge them, while closed-cycle systems circulate working fluids like helium or argon in a loop. Hybrid MHD systems couple an MHD generator with a steam turbine to further improve efficiency. MHD systems have advantages like high efficiency but also disadvantages like high costs and challenges with high temperatures.
This document summarizes research on cooling systems for high heat flux electronics. It discusses direct and indirect liquid cooling systems using single or two-phase flow. Direct systems use coolants like dielectric fluids in contact with chips, while indirect systems use a liquid loop and secondary refrigeration loop. Two-phase microchannel and spray cooling can remove over 800 W/cm2. Refrigeration systems maintain low chip temperatures below 125°C even at over 1000 W/cm2. Flow instabilities are a challenge, and active control methods are needed for transient applications. Advanced modeling and control strategies may enable effective cooling of future high-power electronics.
Thermal energy is the total kinetic and potential energy of particles in a substance. Thermal energy increases with temperature and mass. Thermal power plants convert heat energy from combustion of fuels like coal into electrical energy. They are major sources of electricity but also pollute the environment. Improving efficiency and using techniques like flue gas heat recovery and dry coal can reduce their environmental impact.
REVIEW OF THERMAL ENERGY STORAGE SYSTEMS AND THEIR APPLICATIONSijiert bestjournal
Nowadays,the worldwide worry about a global climat e change pushes to develop new energetic strategies. And more,after the recent energetic cr isis due to the increase of oil price,or the gas crisis arisen between Russia and Ukraine This paper reviews the Thermal energy storage systems which have the potential for increasing the effecti ve use of thermal energy equipment and for facilitating large-scale switching. They are normal ly useful for correcting the mismatch between the supply and demand of energy. There are different me thods in thermal storage systems.
A review of the growth of the Israel Genealogy Research Association Database Collection for the last 12 months. Our collection is now passed the 3 million mark and still growing. See which archives have contributed the most. See the different types of records we have, and which years have had records added. You can also see what we have for the future.
This presentation includes basic of PCOS their pathology and treatment and also Ayurveda correlation of PCOS and Ayurvedic line of treatment mentioned in classics.
বাংলাদেশের অর্থনৈতিক সমীক্ষা ২০২৪ [Bangladesh Economic Review 2024 Bangla.pdf] কম্পিউটার , ট্যাব ও স্মার্ট ফোন ভার্সন সহ সম্পূর্ণ বাংলা ই-বুক বা pdf বই " সুচিপত্র ...বুকমার্ক মেনু 🔖 ও হাইপার লিংক মেনু 📝👆 যুক্ত ..
আমাদের সবার জন্য খুব খুব গুরুত্বপূর্ণ একটি বই ..বিসিএস, ব্যাংক, ইউনিভার্সিটি ভর্তি ও যে কোন প্রতিযোগিতা মূলক পরীক্ষার জন্য এর খুব ইম্পরট্যান্ট একটি বিষয় ...তাছাড়া বাংলাদেশের সাম্প্রতিক যে কোন ডাটা বা তথ্য এই বইতে পাবেন ...
তাই একজন নাগরিক হিসাবে এই তথ্য গুলো আপনার জানা প্রয়োজন ...।
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How to Fix the Import Error in the Odoo 17Celine George
An import error occurs when a program fails to import a module or library, disrupting its execution. In languages like Python, this issue arises when the specified module cannot be found or accessed, hindering the program's functionality. Resolving import errors is crucial for maintaining smooth software operation and uninterrupted development processes.
A workshop hosted by the South African Journal of Science aimed at postgraduate students and early career researchers with little or no experience in writing and publishing journal articles.
it describes the bony anatomy including the femoral head , acetabulum, labrum . also discusses the capsule , ligaments . muscle that act on the hip joint and the range of motion are outlined. factors affecting hip joint stability and weight transmission through the joint are summarized.
Strategies for Effective Upskilling is a presentation by Chinwendu Peace in a Your Skill Boost Masterclass organisation by the Excellence Foundation for South Sudan on 08th and 09th June 2024 from 1 PM to 3 PM on each day.
How to Make a Field Mandatory in Odoo 17Celine George
In Odoo, making a field required can be done through both Python code and XML views. When you set the required attribute to True in Python code, it makes the field required across all views where it's used. Conversely, when you set the required attribute in XML views, it makes the field required only in the context of that particular view.
Chapter wise All Notes of First year Basic Civil Engineering.pptxDenish Jangid
Chapter wise All Notes of First year Basic Civil Engineering
Syllabus
Chapter-1
Introduction to objective, scope and outcome the subject
Chapter 2
Introduction: Scope and Specialization of Civil Engineering, Role of civil Engineer in Society, Impact of infrastructural development on economy of country.
Chapter 3
Surveying: Object Principles & Types of Surveying; Site Plans, Plans & Maps; Scales & Unit of different Measurements.
Linear Measurements: Instruments used. Linear Measurement by Tape, Ranging out Survey Lines and overcoming Obstructions; Measurements on sloping ground; Tape corrections, conventional symbols. Angular Measurements: Instruments used; Introduction to Compass Surveying, Bearings and Longitude & Latitude of a Line, Introduction to total station.
Levelling: Instrument used Object of levelling, Methods of levelling in brief, and Contour maps.
Chapter 4
Buildings: Selection of site for Buildings, Layout of Building Plan, Types of buildings, Plinth area, carpet area, floor space index, Introduction to building byelaws, concept of sun light & ventilation. Components of Buildings & their functions, Basic concept of R.C.C., Introduction to types of foundation
Chapter 5
Transportation: Introduction to Transportation Engineering; Traffic and Road Safety: Types and Characteristics of Various Modes of Transportation; Various Road Traffic Signs, Causes of Accidents and Road Safety Measures.
Chapter 6
Environmental Engineering: Environmental Pollution, Environmental Acts and Regulations, Functional Concepts of Ecology, Basics of Species, Biodiversity, Ecosystem, Hydrological Cycle; Chemical Cycles: Carbon, Nitrogen & Phosphorus; Energy Flow in Ecosystems.
Water Pollution: Water Quality standards, Introduction to Treatment & Disposal of Waste Water. Reuse and Saving of Water, Rain Water Harvesting. Solid Waste Management: Classification of Solid Waste, Collection, Transportation and Disposal of Solid. Recycling of Solid Waste: Energy Recovery, Sanitary Landfill, On-Site Sanitation. Air & Noise Pollution: Primary and Secondary air pollutants, Harmful effects of Air Pollution, Control of Air Pollution. . Noise Pollution Harmful Effects of noise pollution, control of noise pollution, Global warming & Climate Change, Ozone depletion, Greenhouse effect
Text Books:
1. Palancharmy, Basic Civil Engineering, McGraw Hill publishers.
2. Satheesh Gopi, Basic Civil Engineering, Pearson Publishers.
3. Ketki Rangwala Dalal, Essentials of Civil Engineering, Charotar Publishing House.
4. BCP, Surveying volume 1
Beyond Degrees - Empowering the Workforce in the Context of Skills-First.pptxEduSkills OECD
Iván Bornacelly, Policy Analyst at the OECD Centre for Skills, OECD, presents at the webinar 'Tackling job market gaps with a skills-first approach' on 12 June 2024
1. ASSIGNMENT OF POWER PLANT
ENGINEERING
TOPIC:-GEOTHERMAL POWER PLANT
SUBMITTED BY:-
Ankur kumar
)
2. ABSTRACT
The paper gives an overview of the existing power plant technology. It addresses
various problems that have been encountered, and outlines countermeasures
that have been applied. Two main types of geothermal power plants are
common, the condensing power plant, using fluid from reservoirs with
temperatures in the range 200–320°C, and the binary fluid power plant using
temperatures as low as 120°C.
Also featured are the principal advantages appropriate to the utilization
ofgeothermal resources for production of electricity.The paper moreover touches
upon some of the advantages accruable from the integrated use of geothermal
resources (using the same resource for electricity production in cascade or
parallel with production of hot water for alternative uses), taking hybrid
conversion as a case in point.Also featured is a worldwide overview of the
geothermal power plants by Bertani(under the auspices of IGA in 2005). The
survey categorises the power plants bycountry, type of power conversion system
used, and its role with respect to the country’s total electricity generation and
total power demand. Also addressed is the actual geothermal electric power
generation per continent relative to actual totalinstalled plant capacity. Finally
the survey features the effect of resource temperature on the power generation
density.
Environmental abatement measures, such as re-injection of the spent (denuded
of most of its thermal energy) geothermal fluid and methods of minimizing
atmospheric contamination by CO2 and H2S gases are also outlined, and so are
the main associated technical problems.The paper closes with a comprehensive
list of the parameters that should be considered in designing a sustainable
geothermal application scenario.
3. 1. INTRODUCTION
The generation of electrical power using the thermal energy contained in the fluid
circulating in deep lying formations in geothermal areas is typically quite feasible
in the fluid temperature range of 200°C to 320°C, which characterises so called
high-temperature (high enthalpy) geothermal areas.
Geothermal fluid of this temperature is generally mined using current technology
at resource depths Eliasson et al. 2 Geothermal Power Plantsbetween about
1200 m to 2500 – 3000 m in Iceland and most other geothermal areas of the
world, for instance the USA, the Philippines, Indonesia, Japan, New Zealand,
Mexico, and Kenya to name a few.
Geothermal energy is renewable, when measured relative to human age spans,
and generallycategorised as such. It is environmentally benign (“green”) and has
many advantages over other renewable energy resources, such as hydro, wind,
bioenergy and wave energy. The following are the more important of these
advantages:
High degree of availability (>98% and 7500 operating hrs/annum common)
Low land use
Low atmospheric pollution compared to fossil fuelled plants
Almost zero liquid pollution with re-injection of effluent liquid
Insignificant dependence on weather conditions
Comparatively low visual impact
In compliance with current environmental, resource and economic sustainability
principles it(Axelsson et al., 2001, 2003, and 2005) is important to select
technologies and operational systems forthe highest possible over all thermal
4. efficiency for extracting the useful thermal energy, contained inthe fluid, before
it is returned back to the reservoir. The advantage of adopting such policies is
the reduced number of production and injection wells required, less
replacement drilling, higher level ofsustainability, and greater environmental
benefits.
These advantages may be attained in several ways, the optimal of which are
multiple use (e.g. simultaneous electricity plus hot water production) systems and
hybrid power plants.The following chapter addresses the most common types of
technologies applied in the conversion of geothermal energy into electric power;
reviews some of the associated problems, and availablecountermeasures.
2. OVERVIEW OF POWER PLANT DESIGNS
This chapter addresses the geothermal to electrical power conversion systems
typically in use in the world today. These may be divided into three basic
systems, wiz:
Flashed steam/dry steam condensing system; resource temperature range
from about 320°C to some 230°C
Flashed steam back pressure system; resource temperature range from
about 320°C to some 200°C
Binary or twin-fluid system (based upon the Kalina or the Organic Rankin
cycle); resource temperature range between 120°C to about 190°C
In addition to the above three basic power conversion systems, there are in use,
the so called hybrid systems, which are in fact a combined system comprising two
or more of the above basic types in series and/or in parallel.
5. Condensing and back pressure type geothermal turbines are essentially low
pressure machines designed for operation at a range of inlet pressures ranging
from about 20 – 2 bar, and saturated steam.
They are generally manufactured in output module sizes of the following power
ratings, i.e. 25 MW, 35 MW, 55 MW and 105 MW (the largest currently
manufactured geothermal turbine unit is 117MW). Binary type low/medium
temperature units, whereof the Kalina Cycle or Organic Rankin Cycletype, are
typically manufactured in smaller modular sizes, i.e. ranging between 1 MWe and
10 MWin size. Larger units specially tailored to a specific use are, however,
available typically at a somewhat higher price. .
2.1 Back pressure type systems
Back pressure type systems are the simplest of the above, least expensive and
have the lowest overall thermal efficiency. Currently they are largely used in
multiple use applications (such as combined electricity and hot water production),
to provide temporary power during resource development, in the mineral mining
industry where energy efficiency has low priority, and most importantly as part of
a hybrid system. Their stand-alone scope of application covers the whole of the
normally useful geothermal resource temperature range, i.e. from about 320°C
to some 200°C.
2.2 Condensing type systems
Condensing type systems are somewhat more complex in as much as they require
a condenser, and gas exhaust system. This is the most common type of power
conversion system in use today. The turbineis an expansion machine and the unit
normally comprises two turbine sets arranged coaxially cheek to cheek (hp end to
hp end) to eliminate/minimise axial thrust. To improve its thermal efficiency and
flexibility, the unit is also available in a twin pressure configuration (say 7 bar/2
bar), where the lower pressure (say 2 bar) steam is induced downstream of the
6. third expansion stage. When these condensing turbines are used in a co-
generation scheme they may be fitted with extraction points to
provide low pressure steam to the district heating side. The hallmarks of the
condensing system are long and reliable service at reasonable over all thermal
efficiency, and good load following capability. Their stand-alone scope of
application covers the high to medium (200–320°C) geothermal resource
temperature range.
2.3 Binary type systems
Binary type systems are of a quite different concept. The thermal energy of the
geothermal fluid from the production well field is transferred to a secondary fluid
system via heat exchangers . The geothermal fluid is thus isolated from the
secondary fluid, which comprises a low boiling point carbohydrate (butane,
propane etc.) or specially designed low boiling point fluid, which complies with
low ozone layer pollution constraints, in the case of the Organic Rankin Cycle . In
the case of the Kalina Cycle, the secondary or motive liquid comprises water
solution of ammonia. This heated secondary fluid thereupon becomes the motive
fluid driving the turbine/generator unit. The hallmark of the binary system is its
ability to convert low-temperature (120–190°C) geothermal energy to electric
power albeit at a relatively low overall thermal efficiency, and to isolate scaling,
gas and erosion problems at an earlypoint in the power conversion cycle. The
binary system is quite complex and maintenance intensive.
Typical geothermal back pressure, condensing, binary and hybrid systems are
depicted in Figures 1, 2, 3, 4, 5and 6.
7.
8.
9.
10. 2.4 Hybrid conversion system
The hybrid conversion system is a combined system, as said before,encompassing
two or more of the basic types in series and/or in parallel. Their hallmark is
versatility, increased o/a thermal efficiency, improved load following capability,
and ability to efficiently cover the medial (200–260°C) resource temperature
range (Tester, 2007). To illustrate the concept a hybrid configuration
encompassing a backpressure flashed steam turbine/generator unit and three
binary t/units in series is depicted inFigure 4. Two of the binary units utilise the
exhaust steam from the back pressure unit, and theremaining binary t/g unit
utilises the energy content of the separator fluid. The fluid effluent streams are
then combined for re-injection back into the geothermal reservoir, so maintaining
sustainability of the resource in a most elegant manner.
11. 3. PREVAILING PROBLEM TYPES AND COUNTERMEASURES IN
OPERATION OF POWER PLANTS
Different parts of the surface components of power generation system have
associated different problem flora. It is therefore expedient to divide the system
into the following seven principal portions:
Power house equipment: Comprising of turbine/generator unit complete
with condenser, gas exhaust system,
Automatic control and communication system: Consisting of frequency
control, servo valve control, computer system for data collection, resource
and maintenance monitoring, internal and external communication etc.
Cooling system: Cooling water pumps, condensate pumps, fresh water
(seawater) cooling, or cooling towers,
Particulate and/or droplet erosion: This is an erosion problem that is
typically associated with the parts of the system where the fluid is
accelerated (e.g. in control valves, turbine nozzles, etc.) and/or abruptly
made change direction (e.g. via pipe bends, T-fittings or wanes),
Heat exchangers: These are either of the plate or the tube and shell type.
These are generally only used in binary and hybrid type conversion
systems, and/or in integrated systems.
Gas evacuation systems: High temperature geothermal fluid contains a
significant quantity of non-condensable gases (C02, N2, H2S, and others).
These have to be removed for instance from the condensing plant for
reasons of conversion efficiency and to minimise atmospheric pollution.
Re-injection system: Comprising liquid effluent collection pipelines,
injection pumps, injection pipelines, injection wells and control system.
The problem areas typical for each of these conversion components are now
outlined in turn each under its own chapter heading. It must, however,
beemphasized that the featured problems and counter measures can only be
addressed in general terms because of their site and locality specific nature. A
locality specific case by case pre-engineering study is decidedly required in order
to address this subject matter in any detail.
12. 4.1 Power house equipment
4.1.1 Turbine
The problems potentially associated with the turbine are scaling of the flow
control valve and nozzles (primarily in the stator inlet stage); stress corrosion of
rotor blades; erosion of turbine (rotor and stator) blades and turbine housing.
The rate and seriousness of scaling in the turbine are directly related to the steam
cleanliness, i.e. the quantity and characteristics of separator “carry-over“. Thus
the operation and efficiency of theseparator are of great importance to trouble
free turbine operation. Prolonged operation of the powerplant off-design point
also plays a significant role.
Most of the scaling takes place in the flow control valve and the first stator nozzle
row. The effect of this scaling is:
A significant drop-off in generating capacity as sufficient steam cannot
enter theturbine
Sluggish response to load demand variations.
This situation is easily monitored, since the build-up of scales causes the pressure
in the steam chestbetween the control valve and the inlet nozzles to increase
over time.
Significant turbine and control valve scaling is avoided by the adoption of careful
flasher/separator plant operating practices that minimise “carry-over“, and
moreover selecting a high efficiency misteliminator by the power plant.
Significant scaling in turbine and control valve requires scheduled maintenance
stops for inspection and cleaning, say every second or third year. Another means
of reducing turbine cleaning frequency, is to inject condensate into the inlet
steam during plant operation and run the turbine at say 10% wetness for a short
period. This washes awaynozzle scaling, in particular the calcite component
thereof, and simultaneously weakens the silica scalestructure, which then tends
13. to break off. This cleaning technique if properly applied has been found toreduce
the frequency of major turbine overhaul.
4.1.2 Generator
It must be pointed out here that high-temperature steam contains a significant
amount of carbondioxide CO2 and some hydrogen sulphite H2S and
theatmosphere in geothermal areas is thus permeated by these gases. All
electrical equipment and apparatus contains a lot of cuprous or
silvercomponents, which are highly susceptible to sulphite corrosion and thus
have to be kept in an H2S free environment.
The power generator is therefore either cooled by nitrogen gas or atmospheric air
that has been cleaned of H2S by passage through special active carbon filter
banks.
4.1.3 Condenser
The steam-water mixture emitted from the turbine at outlet contains a significant
amount of non condensablegases comprising mainly CO2(which is usually 95–
98% of the total gas content), CH4Eliasson et al. 10 Geothermal Power Plants
and H2S, and is thus highly acidic. Since most high-temperature geothermal
resources are located inarid or semi-arid areas far removed from significant
freshwater (rivers, lakes) sources, the condenser cooling choices are mostly
limited to either atmospheric cooling towers or forced ventilation ones.
The application of evaporative cooling of the condensate results in the
condensate containing dissolved oxygen in addition to the non-condensable
gases, which make the condenser fluid highlycorrosive and require the condenser
to be clad on the inside with stainless steel; condensate pumps to be made of
stainless steel, and all condensate pipelines either of stainless steel or glass
reinforcedplastic. Addition of caustic soda is required to adjust the pH in the
cooling tower circuit. Make-up water and blow-down is also used to avoid
accumulation of salts in the water caused by evaporation.
14. A problem sometimes encountered within the condenser is the deposition of
almost pure sulphur on walls and nozzles within the condenser. This scale
deposition must be periodically cleaned by high pressure water spraying etc.
4.2 Automatic control and communication system
Modern power plants are fitted with a complex of automatic control apparatus,
computers and various forms of communication hardware. These all have
components of silver and cuprous compounds that are extremely sensitive to H2S
corrosion. They are therefore housed inside “clean enclosures”, i.e. airtight
enclosures that are supplied with atmospheric air under pressure higher than that
of the ambient atmospheric one and specially scrubbed of H2S. Entrance and exit
from this enclosure is through a clean air blow-through antechamber to prevent
H2S ingress via those entering the enclosure.A more recent design is to clean all
the air in all control rooms by special filtration and maintainOverpressure.
Most other current carrying cables and bus bars are of aluminium to prevent H2S
corrosion. Where copper cables are used a field applied hot-tin coating is applied
to all exposed ends.
4.3 Cooling tower system
4.3.1 Cooling tower and associated equipment
Most high-temperature geothermal resources are located in arid or semi-arid
areas far removed from significant freshwater (rivers, lakes) sources. This mostly
limits condenser cooling choices to eitheratmospheric cooling towers or forced
ventilation ones. Freshwater cooling from a river is however, used for instance
in New Zealand and seawater cooling from wells on Reykjanes, Iceland.
In older power plants the atmospheric versions and/or barometric ones were
most often chosen . Most frequently chosen for modern power plants is the
forced ventilation type because of environmentalissues and local proneness to
earth quakes.
15. The modern forced ventilation cooling towers are typically of wooden/plastic
construction comprisingseveral parallel cooling cells erected on top of a lined
concrete condensate pond. The ventilation fans are normally vertical, reversible
flow type and the cooling water pumped onto a platform at the top of the tower
fitted with a large number of nozzles, through which the hot condensate drips in
counter -flow to the airflow onto and through the filling material in the tower and
thence into the condensate pond, whence the cooled condensate is sucked by the
condenser vacuum back into the condenser. To minimise scaling and corrosion
effects the condensate is neutralised through pH control, principally via addition
of sodium carbonate.Three types of problems are found to be associated with the
cooling towers, i.e.:
Icing problems in cold areas
Sand blown onto the tower in sandy and arid areas
Clogging up by sulphitephylic bacteria
The first mentioned is countered by reversing the airflow cell by cell in rotation
whilst operating thus melting off any icing and snow collecting on the tower.
The second problem requires frequent cleaning of nozzles and condensate pond.
The last mentioned is quite bothersome. It is most commonly alleviated by
periodic application of bacteria killing chemicals, and cleaning of cooling tower
nozzles by water jetting. The sludge accumulation in the condensate pond,
however, is removed during scheduled maintenance stops. A secondary problem
is the deposition of almost pure sulphur on walls and other surfaces within the
condenser . It must beperiodically cleaned by high pressure water spraying etc.,
which must be carried out during scheduled turbine stops.
4.3.2 Condenser pumping system
The condensate pumps must, as recounted previously, be made of highly
corrosion resistant materials, and have high suction head capabilities. They are
mostly trouble free in operation.The condensate pipes must also be made of
16. highly corrosion resistant materials and all joints efficiently sealed to keep
atmospheric air ingress to a minimum, bearing in mind that such pipes are all
in a vacuum environment. Any air leakage increases the load on the gas
evacuation system and thus the ancillary power consumption of the power plant.
4.4 Particulate/droplet erosion and countermeasures
Geothermal production wells in many steam dominated reservoir have entrapped
in the well flow minute solids particles (dust), which because of the prevailing
high flow velocities may cause particulate erosion in the well head and
downstream of it. Such erosion in the well head may, inextreme cases, cause
damage of consequence to wellhead valves, and wellhead and fittings,particularly
in T-fittings and sharp bends in the fluid collection pipelines. This is, however,
generallynot the case and such damage mostly quite insignificant. It is, however,
always a good practice to use fairly large radius pipe bends to minimise any such
erosion effects.
Droplet erosion is largely confined to the turbine rotor and housing. At exit from
the second or the third expansion stage the steam becomes wet and condensate
droplets tend to form in and after theexpansion nozzles. Wetness of 10% to 12%
is not uncommon in the last stages. The rotor blades have furthermore reached a
size where the blade tip speeds become considerable and the condensate
droplets hit the blade edges causing erosion. The condensate water which has
become acidic from the dissolved non condensable gas attaches to the blades and
is thrown against the housing. This water has the potential to cause erosion
problems. The most effective countermeasures are to fit the blade edges of the
last two stages with carbide inserts (Stellite) that is resistant to the droplet
impingement and the housing with suitable flow groves that reduce the
condensate flow velocity and thereby potential erosion damage.
In addition to the erosion the blades and rotor are susceptible to stress corrosion
in the H 2S environment inside the turbine housing. The most effective
countermeasure is to exercise great care in selecting rotor, expansion nozzle and
17. rotor blade material that is resistant to hydrogen sulphitecorrosion cracking. The
generally most effective materials for the purpose are high chromium steels.
4.5 Heat exchangers
In high-temperature power generation applications heat exchangers are generally
not used on the well fluid. Their use is generally confined to ancillary uses such as
heating, etc. using the dry steam. In cogeneration plants such as the
simultaneous production of hot water and electricity, their use is universal. The
exhaust from a back pressure turbine or tap-off steam from a process turbine is
passed as primary fluid through either a plate or a tube and shell type heat
exchanger. The plate type heatexchanger was much in favour in cogeneration
plants in the seventies to nineties because of theircompactness and high
efficiency. They were, however, found to be rather heavy in maintenance.
Thesecond drawback was that the high corrosion resistance plate materials
required were only able towithstand a relatively moderate pressure difference
between primary and secondary heat exchanger media. Thirdly the plate seals
tended to degenerate fairly fast and stick tenaciously to the platesmaking
removal difficult without damaging the seals. The seals that were needed to
withstand the required temperature and pressure were also pricy and not always
in stock with the suppliers. This hasled most plant operators to change over to
and new plant designers to select the shell and tube configurations, which
demand less maintenance and are easily cleaned than the plate type though
requiring more room.
In low-temperature binary power plants shell and tube heat exchangers are used
to transfer the heat from the geothermal primary fluid to the secondary (binary)
fluid. They are also used ascondensers/and or regenerators in the secondary
system.
18. In supercritical geothermal power generation situation it is foreseen that shell
and tube heat exchangers will be used to transfer the thermal energy of the
supercritical fluid to the production of clean steam to power the envisaged power
conversion system.
In all instances it is very important to select tube and/or plate materia l in contact
with the geothermal fluid that will withstand the temperature, pressure and
corrosion potential of the fluid . Some inconel, itanium and duplex stainless steel
alloys have given good service. It is also important to make space allowance for
tube withdrawal for maintenance and/or tube cleaning procedures. High pressure
water-jet cleaning has for instance proved its value.
Scaling will normally be present. Provisions should therefore be made timely for
scale abatement such as by hydrothermal operation or chemical scale inhibitor
injection, and/or mechanical cleaning.
4.6 Gas evacuation system
As previously stated the geothermal steam contains a significant quantity of non-
condensable gas (NCG) or some 0.5% to 10% by weight of steam in the very worst
case. To provide and maintainsufficient vacuum in the condenser, the NCG plus
any atmospheric air leakage into the condenser must be forcibly exhausted. The
following methods are typically adopted, viz.:
The use of a single or two stage steam ejectors, economical for NCG
content less than1.5% by weight of steam.
The use of mechanical gas pumps, such as liquid ring vacuum pumps, which
are economical for high concentration of NCG.
The use of hybrid systems incorporating methods 1 and 2 in series.
19. The advantages of the ejector systems are the low maintenance,and high
operational security of such systems. The disadvantage is the significant pressure
steam consumption, which otherwise would be available for power production.
The advantages of the vacuum pumps are the high degree of evacuation possible.
The disadvantage is the electric ancillary power consumption, sensitivity to
particulate debris in the condenser, and highmaintenance requirements.
To reduce the ambient level of H2S in the proximity of the power plant, the
exhausted NCG is currently in most countries discharged below the cooling tower
ventilators to ensure a thorough mixing with the air as it is being blown high into
the air and away from the power plant and itsenvirons. In the USA and Italy H2S
abatement is mandatory by law, and in Italy also mercury (Hg) and thus require
chemical type abatement measures.
In some of the older Geysers field power plants the H2S rich condenser exhaust
was passed through abed of iron and zinc oxide to remove the H2S. These proved
a very messy way of getting rid of the H2S and were mostly abandoned after a
few years. In a few instances the Stretford process and other equivalent ones
have been used upstream of the power plant to convert H2S gas into sulphur for
industrial use. This has proved expensive and complex and is not in use in other
geothermal fields than the Geysers field in California.
The main H2S abatement methods currently in use worldwide are (only some
are currently used forgeothermal NCG):
Claus (Selectox)
HaldorTopsöe – WSA process
Shell-Paques Biological H2S removal process/THIOPAC
LO-CAT (wet scrubbing liquid redox system)
Fe-Cl hybrid process
Aqueous NaOH absorbent process
Polar organic absorbent process
20. 4.7 Re-injection system
In most geothermal areas the geothermal fluid may be considered to be brine
because of the typically high chloride content. It may also contain some
undesirable tracer elements that pose danger to humans, fauna and flora.
In considering the most convenient way of disposing of this liquid effluent other
than into effluent ponds on the surface, the idea of injecting the liquid effluent
back into the ground has been with the geothermal power industry for a long
time (Stefánsson, 1997). Initially the purpose of re-injection was simply to get rid
of the liquid effluent in a more elegant way than dumping it on the surface, into
lakes or rivers, and even to the ocean. Many technical and economic drawbacks
were soon discovered. The more serious of these were the clogging up of
injection wells, injection piping and the formations close to the borehole; the cold
effluent migrated into the production zone so reducing the enthalpy of the well
output with consequent fall-off in power plant output. Injection into sandstone
and other porous alluvial formations was and is fraught with loss of injectivity
problems that are still not fully understood.
Soon, however, it became generally understood and accepted that returning the
effluent liquid back into the reservoir had even greater additional benefits, viz.:
Greatly reducing the rate of reservoir pressure and fluid yield decline
Improved extraction of the heat content contained within the reservoir
formationsReducing the fluid withdrawal effect on surface manifestations,
e.g. hot pools, steam vents etc.
All the above items serve to maintain resource sustainability and are thus of
significant environmental benefit.Re-injection should be considered an integral
part of any modern, sustainable and environmentally friendly geothermal
utilization, both as a method of effluent water disposal and to counteract
pressure draw-down by providing artificial water recharge (Stefánsson, 1997).
Re-injection is essential for sustainable utilization of virtually closed and limited
21. recharge geothermal systems. Cooling of production wells, which is one of the
dangers associated with re-injection, can be minimised through careful testing
and research. Tracer testing, combined with comprehensive interpretation, is
probably the most important tool for this purpose. Many different methods have
and are still being tried to overcome these technical problems mentioned above
such as the use of settling tanks that promote polymerisation of the silica
molecules and settling in the tanks prior to injection; injection of the effluent
liquid directly from the separators at temperatures in the range of 145–160°C, so
called “hot injection”, both to avoid contact with atmospheric air and to hinder
scaling in the injection system; controlling the pH of the effluent commensurate
with reduction in the rate of silica/calcite precipitation using acids and add
condensate from the plant to dilute the silica in the brine, to name a few. The
danger of production well cooling can be minimised through careful testing and
research. Tracer testing, combined with comprehensiveinterpretation, is
probably the most important tool for this purpose. One way to delay the effects
of cooling is also to locate the re-injection wells far enough away from the
production area, say 2 km. Another way gaining popularity is to inject deep into
the reservoir, even where there is small permeability, by pumping at high
pressures (60–100 bar).Surface disposal contravenes the environmental statutes
of most countries and the use of settling tanks has ceased mostly because of
associated cost and complexity. The most commonly adopted injection methods
are the last two, i.e. hot re-injection and chemical pH control ones. The main
disadvantage of the hot re-injection technique is the lowered overall thermal
efficiency and the consequent greater fluid production (more wells to yield the
same power output) required. The main disadvantage of the pH control scheme
is the very large acid consumption (cost) and uncertainties regarding its long-
term effects.
Hot re-injection is precluded in low-temperature power generation and the most
common technique is to make use of the reverse solubility of calcite in water by
operating the conversion system at a pressure level above the CO2 bubble point
and only reduce the pressure once the fluid temperature has attained a level low
enough to prevent calcite dissipation prior to re-injection.