The document summarizes the design of a heat rejection system for a power plant consisting of a shell-and-tube condenser and a natural draft cooling tower. Steam enters the condenser at 46°C and exits as saturated liquid at 10kPa. Cooled water from the tower at 31°C enters the condenser and exits at 41°C. The condenser is designed as two parallel counter-flow heat exchangers based on effectiveness calculations. The cooling tower design is based on energy and mass balances to reject heat from the condenser outlet water to the ambient air. The total cost of the heat rejection system is estimated to be 1.04 billion USD.
The document provides an overview of the course contents for a Power Plant Module. It includes 4 sections: [1] Fundamentals of Thermodynamics covering basics, phases of water, steam properties, thermodynamic laws and cycles; [2] Power Plant Components and applications of thermodynamics; [3] Power Plant Facilities and configurations; [4] Power Plant Operations. Section 1 further outlines topics such as measurable/quantifiable properties, phases of water, steam tables, thermodynamic processes, and cycles like Carnot and Rankine.
This document presents a rule-of-thumb design procedure for wet cooling towers that can be used for power plant cycle optimization. It begins with defining the design problem and specifying inlet/outlet water temperatures and ambient wet-bulb temperature. It then provides methods to calculate the outlet air temperature, tower characteristic, loading factor, and other key parameters. These include using the average of inlet/outlet water temperatures to approximate outlet air temperature, graphically integrating the Merkel equation to determine tower characteristic, and using graphs to determine the optimum loading factor based on design conditions. The goal is to provide simplified methods for estimating cooling tower dimensions, performance, costs and other details needed for power plant analysis without requiring detailed iterative design calculations.
This document summarizes a study on the performance characteristics of counter flow wet cooling towers. The study uses a detailed model to investigate cooling tower performance. It is shown that evaporation contributes the majority (62.5-90%) of the total heat transfer rate from the bottom to the top of the tower. The model accounts for variations in air and water temperatures and properties along the height of the tower. Heat and mass transfer mechanisms are explained using psychrometric charts.
This document provides an overview of cooling tower components and design. It describes the basic components of cooling towers including frames, fill materials, cold water basins, drift eliminators, air inlets, louvers, nozzles, and fans. It also discusses different types of cooling towers, factors that affect performance like wet bulb temperature, and efficient system operation through water treatment and use of efficient fans. The equipment used in this project includes a fan, DC centrifugal pump, sump, and tank. The fan and pump are powered by a DC motor.
1) The revised report analyzes the performance of a cooling tower under varying operating conditions, focusing on efficiencies and characteristics at different water flow rates.
2) Improvements were made to the report, including formatting, removing unnecessary explanations, focusing on theory over derivation, explaining the significance of cooling towers, and providing more detailed conclusions.
3) The results show that increasing the water flow rate decreases the cooling tower characteristic and efficiency, in agreement with previous literature and Merkel theory.
This document provides an overview of an experiment analyzing the performance of a mechanical draft cooling tower. The experiment varied the water flow rate and fan speed to measure water temperature changes. The Merkel equation was then used to calculate the "tower characteristic" or coefficient of performance. As the water to air flow rate ratio (LG) increased, the tower characteristic and efficiency decreased, matching the Merkel theory. The conclusion is that higher water flow rates decrease the cooling tower's efficiency and characteristic.
MERKELS METHOD FOR DESIGNING INDUCED DRAFT COOLING TOWERIAEME Publication
In general, cooling towers are used to dissipate process waste heat into the atmosphere. In this paper, induced draft cooling tower has been designed by simplified merkel’s method. The design of cooling tower is based on Merkel’s method. The t ower characteristic is determined by the ratio of range and log-mean-enthalpy difference. Optimization of the operating conditions for cooling tower applications in cooling water is extremely significant in order to get the most energy efficient operating point for these systems. A simple algebraic formula is used to calculate the optimum water-to-air flow rate. Merkel’s method is the most widely accepted theory for cooling tower calculations. It combines equations for heat and water vapor transfer. The objective of this paper is to present the design procedure of counter – flow cooling towers in a simplified manner
This experiment studied the effects of cooling load and inlet water temperature on a cooling tower's performance. In experiment 1, cooling load was varied at 0.5 kW, 1 kW, and 1.5 kW while water flow rate and air flow were held constant. Higher cooling loads resulted in larger cooling ranges between inlet and outlet water temperatures. Experiment 2 varied water flow rate from 0.8 LPM to 1.6 LPM at a 1 kW cooling load. Higher water flow rates produced smaller cooling ranges and lower heat loads transferred. The results show that increasing cooling load or decreasing water flow rate improves a cooling tower's heat removal capabilities.
The document provides an overview of the course contents for a Power Plant Module. It includes 4 sections: [1] Fundamentals of Thermodynamics covering basics, phases of water, steam properties, thermodynamic laws and cycles; [2] Power Plant Components and applications of thermodynamics; [3] Power Plant Facilities and configurations; [4] Power Plant Operations. Section 1 further outlines topics such as measurable/quantifiable properties, phases of water, steam tables, thermodynamic processes, and cycles like Carnot and Rankine.
This document presents a rule-of-thumb design procedure for wet cooling towers that can be used for power plant cycle optimization. It begins with defining the design problem and specifying inlet/outlet water temperatures and ambient wet-bulb temperature. It then provides methods to calculate the outlet air temperature, tower characteristic, loading factor, and other key parameters. These include using the average of inlet/outlet water temperatures to approximate outlet air temperature, graphically integrating the Merkel equation to determine tower characteristic, and using graphs to determine the optimum loading factor based on design conditions. The goal is to provide simplified methods for estimating cooling tower dimensions, performance, costs and other details needed for power plant analysis without requiring detailed iterative design calculations.
This document summarizes a study on the performance characteristics of counter flow wet cooling towers. The study uses a detailed model to investigate cooling tower performance. It is shown that evaporation contributes the majority (62.5-90%) of the total heat transfer rate from the bottom to the top of the tower. The model accounts for variations in air and water temperatures and properties along the height of the tower. Heat and mass transfer mechanisms are explained using psychrometric charts.
This document provides an overview of cooling tower components and design. It describes the basic components of cooling towers including frames, fill materials, cold water basins, drift eliminators, air inlets, louvers, nozzles, and fans. It also discusses different types of cooling towers, factors that affect performance like wet bulb temperature, and efficient system operation through water treatment and use of efficient fans. The equipment used in this project includes a fan, DC centrifugal pump, sump, and tank. The fan and pump are powered by a DC motor.
1) The revised report analyzes the performance of a cooling tower under varying operating conditions, focusing on efficiencies and characteristics at different water flow rates.
2) Improvements were made to the report, including formatting, removing unnecessary explanations, focusing on theory over derivation, explaining the significance of cooling towers, and providing more detailed conclusions.
3) The results show that increasing the water flow rate decreases the cooling tower characteristic and efficiency, in agreement with previous literature and Merkel theory.
This document provides an overview of an experiment analyzing the performance of a mechanical draft cooling tower. The experiment varied the water flow rate and fan speed to measure water temperature changes. The Merkel equation was then used to calculate the "tower characteristic" or coefficient of performance. As the water to air flow rate ratio (LG) increased, the tower characteristic and efficiency decreased, matching the Merkel theory. The conclusion is that higher water flow rates decrease the cooling tower's efficiency and characteristic.
MERKELS METHOD FOR DESIGNING INDUCED DRAFT COOLING TOWERIAEME Publication
In general, cooling towers are used to dissipate process waste heat into the atmosphere. In this paper, induced draft cooling tower has been designed by simplified merkel’s method. The design of cooling tower is based on Merkel’s method. The t ower characteristic is determined by the ratio of range and log-mean-enthalpy difference. Optimization of the operating conditions for cooling tower applications in cooling water is extremely significant in order to get the most energy efficient operating point for these systems. A simple algebraic formula is used to calculate the optimum water-to-air flow rate. Merkel’s method is the most widely accepted theory for cooling tower calculations. It combines equations for heat and water vapor transfer. The objective of this paper is to present the design procedure of counter – flow cooling towers in a simplified manner
This experiment studied the effects of cooling load and inlet water temperature on a cooling tower's performance. In experiment 1, cooling load was varied at 0.5 kW, 1 kW, and 1.5 kW while water flow rate and air flow were held constant. Higher cooling loads resulted in larger cooling ranges between inlet and outlet water temperatures. Experiment 2 varied water flow rate from 0.8 LPM to 1.6 LPM at a 1 kW cooling load. Higher water flow rates produced smaller cooling ranges and lower heat loads transferred. The results show that increasing cooling load or decreasing water flow rate improves a cooling tower's heat removal capabilities.
The document discusses cooling towers, including:
1. Types of cooling towers like natural draft, mechanical draft, forced draft, induced draft, cross flow and counter flow towers.
2. Parameters for assessing cooling tower performance including range, approach, effectiveness and cooling capacity.
3. Energy efficiency opportunities like selecting an appropriately sized tower, using efficient fill media to reduce pumping needs, and optimizing fans and motors.
Piping For Cooling Water Circulation between Cooling Tower and CondenserIJSRD
In thermal power plant, as we know that exhaust steam from turbine goes to heat recovery unit and from there the exhaust stem goes to the condenser to condense. In shell and tube heat exchanger, cooling water as a cooling medium running inside the tubes whereas steam is inside the shell. So to have sufficient amount of cooling water, we require continuous flow of water from the cooling tower. Our main project aim is to provide a piping between condenser and cooling tower. So in this particular project, we will make basic documents such as pfd, p&id, plot plan, equipment layout, piping ga drawing, isometrics, mto, piping specifications, pump specification, calculations, and stress analysis etc.
This document discusses predicting the cold water temperature of a cooling tower under different conditions. It begins by explaining cooling tower theory and the accepted performance equation. It then shows how to calculate the tower characteristics (NTU) at design conditions using the Merkel equation. This involves calculating parameters like L/G ratio, enthalpy differences, and incremental NTU values. The example calculates the design tower characteristic (NTU) of 1.367 for a cooling tower in Mumbai with given design temperatures. It further demonstrates how to predict the new tower characteristic if the wet bulb temperature changes while other factors remain constant.
As run energy efficiency of cooling towersD.Pawan Kumar
This document discusses factors that affect the energy efficiency of cooling towers, including entering wet bulb temperature, cooling range, effectiveness, and approach temperature. It notes that simultaneous achievement of maximum range, capacity, and effectiveness with lowest input energy is desirable. The performance of cooling towers in actual operation should be assessed against design conditions and performance curves. Key factors to examine include heat load, water flow, fan power, range, and effectiveness. Optimizing factors like fan operation, cycles of concentration, drift eliminators, and load segregation can improve efficiency.
In this Thesis I will try to understand the concept associated with cooling towers and model a laboratory sized cooling tower in a software package called Engineering Equation Solver (EES). An example of system modelling is presented in this progress report, along with the comparison of a set of results with an experimental data from P.A Hilton Model H892 Bench top cooling tower with a maximum of 9% error. A user interface is also modelled to simulate off-design performance rather than conducting experiments. It also allows you to do additional scenarios that cannot be practically being done in lab,
like Relative humidity, etc.
The document discusses a seminar on studying the behavior of hyperbolic cooling tower shells with pipe openings using a 1:50 scale model subjected to seismic loads. Hyperbolic cooling towers are large reinforced concrete structures that extract heat from water to cool it. The seminar focuses on analyzing a scaled down model of a cooling tower subjected to earthquake loads. Sensors are placed on the model to measure strains and deflections under simulated seismic conditions to understand how the structure responds.
the final abstract of our major project for the award of the degree of bachel...Sourav Lahiri
Cooling towers are heat rejection devices that allow industrial processes to reuse water by cooling it through evaporation. There are several types of cooling towers based on their design and operating principles. The key types are wet cooling towers, which use direct evaporation to cool water below the ambient air temperature, and closed circuit cooling towers, which protect process water from exposure while still enabling evaporative cooling. Cooling towers have evolved from early designs like spray ponds and platform towers to modern configurations that optimize heat transfer, such as those using fill materials to increase surface area between air and water flows.
The document discusses the history and scientific development of cooling tower design theory. It begins by explaining how Merkel developed the first scientific theory for evaluating cooling tower performance in 1925. It then provides definitions of key cooling tower concepts like approach, range, and heat transfer methods. The document goes on to describe parameters like tower characteristics, fan power requirements, and water loss factors. It also summarizes Merkel's assumptions and the development of generalized supply equations from manufacturer curves.
Cooling Tower: Types and performance evaluation, Efficient system operation, Flow control strategies and energy saving opportunities, Assessment of cooling towers
This document summarizes water treatment methods for cooling towers. It discusses corrosion inhibition, scale inhibition, and bacterial control, which are the three main objectives of water treatment. For each objective, it describes the causes of problems, prevention methods, and common chemical and physical treatment methods. It also covers water treatment system controls and monitoring, occupational safety considerations, and definitions of key terms related to water treatment. The intended audience includes cooling tower owners, designers, and operators to help them properly design, operate, and maintain water treatment systems for cooling towers.
Four students designed and modeled a counter flow cooling tower for an air conditioning system with 578 ton cooling capacity. They developed a thermodynamic model based on Merkel's theory and implemented it in a computer program. Their model determined the optimal water to air mass flow ratio matched the cooling tower characteristic and packing function. Their results showed the cooling tower area increases with higher inlet air humidity and larger temperature range.
The document discusses forced draft cooling towers and their components. It describes the key parts including fans, drift eliminators, fills, nozzles, and basins. It also covers topics like packing materials, water and salt balances, windage losses, heat balances, biocides, chlorine dioxide production, and links to additional resources.
This document describes the process of how wet cooling towers function to transfer waste heat from industrial processes to the atmosphere. The warm water returns to the top of the cooling tower and trickles down over fill material, contacting an upward flow of ambient air induced by fans. This contact causes some of the water to evaporate, cooling the remaining water which is then ready to recirculate. Dissolved salts are left behind in the water, increasing its concentration, so blowdown removes some water to control the salt level while fresh makeup water is added to compensate for losses from evaporation, drift, and blowdown.
Analysis of forced draft cooling tower performance using ansys fluent softwareeSAT Journals
Abstract In this project the cooling tower performance has been analyzed by varying air inlet parameters with different air inlet angles and by attaching a nozzle in air inlet. The cooling tower analyzed here is used specifically for small scale industries, which is forced draft counter-flow cooling tower with single module capacities from 10 to 100 cooling tons. In this project 50 tons cooling capacity model has been taken as reference model. The analysis has been done using computational fluid dynamics (CFD) ANSYS 14.5 software. The cooling tower models have been modeled using SOLIDWORKS 2013 software and they have been meshed using ICEM CFD 14.5 software. The meshed models have been analyzed using FLUENT software. The air inlet angles varied in horizontal direction, vertical direction and by combining both horizontal and vertical inclination. A convergent nozzle has been modeled and assembled to the inlet pipe. The temperature contours of the cooling tower models have been taken from the analysis. Based on the outlet cold water temperature, the improved effectiveness of the cooling tower model has been obtained.
Keywords: Forced draft cooling tower, Air inlet parameter, Convergent nozzle, Cooling ton capacity, Counter flow cooling tower, Ansys 14.5, Solidworks 2013, ICEM CFD 14.5, Effectiveness of cooling tower.
This document provides a summary of the selection process for a water cooled chiller system for Comin Khmere Co. Ltd. The following key steps are described:
1) A building load calculation using HAP software determined a total cooling load of 2357 kW. This required selecting a chiller with a 843.9 kW cooling capacity and 4 chillers total.
2) A 1012.68 kW cooling tower was selected based on the chiller condenser load and design parameters.
3) Pumps were selected to move 40.4 l/s of chilled water and 48.5 l/s of condenser water, with pressure drops of 270 kPa and 280 kPa respectively accounted
This document provides an overview of cooling towers. It begins with introductions and definitions, explaining that cooling towers reject heat from condenser water to the ambient air. It then discusses cooling tower fundamentals, components, performance factors like approach and effectiveness. It outlines the heat transfer process. It describes the two main types of cooling towers: natural draft and mechanical draft. Finally, it lists several parameters for assessing cooling tower performance, such as range, approach, effectiveness, cooling capacity, and cycles of concentration.
This document is a report on a study of cooling towers conducted by five mechanical engineering students at Delhi Technological University. It provides an overview of cooling towers, including their components, materials, types, and ways to assess performance and increase energy efficiency. The two main types are natural draft towers, which use temperature differences to circulate air without fans, and mechanical draft towers, which use large fans. The report evaluates selecting the right tower, fill media effects, pumps, distribution systems, fans and more to optimize efficiency. It includes acknowledgments, objectives, figures, tables, and conclusions from the study.
A natural draft cooling tower uses convection to remove waste heat from water and release it into the atmosphere. It has no mechanical components and relies on the natural draft or stack effect to circulate air through the tower. Hot water is distributed through fill material inside the reinforced concrete shell where it comes into contact with rising ambient air, causing heat to transfer from the water to the air through evaporation and cooling the water.
This document compares the thermal performances of plate-fin and pin-fin heat sinks subject to an impinging flow. Experiments are conducted for various flow rates and channel widths to collect data on pressure drop and thermal resistance. A model is developed based on a volume averaging approach to predict these parameters. The optimized plate-fin and pin-fin heat sinks are then compared using the model. A contour map is presented showing the ratio of thermal resistances of the optimized designs as a function of dimensionless pumping power and length. The map indicates pin-fin heat sinks have lower resistance when pumping power is small and length is large, while plate-fin heat sinks perform better when pumping power is large and length is small.
Convection is the transfer of heat by the motion of liquids and gases. It occurs due to differences in density caused by temperature variations. There are two types of convection: free convection, which occurs due to natural density differences, and forced convection, where an external force circulates the fluid. The rate of convective heat transfer depends on properties of the fluid and surface, and can be calculated using empirical correlations that involve parameters like Reynolds number, Nusselt number, and Prandtl number. Boiling and condensation are specific types of phase-change heat transfer that occur at saturated temperatures. Different regimes like nucleate boiling or film boiling depend on the temperature difference between the surface and fluid.
The document discusses cooling towers, including:
1. Types of cooling towers like natural draft, mechanical draft, forced draft, induced draft, cross flow and counter flow towers.
2. Parameters for assessing cooling tower performance including range, approach, effectiveness and cooling capacity.
3. Energy efficiency opportunities like selecting an appropriately sized tower, using efficient fill media to reduce pumping needs, and optimizing fans and motors.
Piping For Cooling Water Circulation between Cooling Tower and CondenserIJSRD
In thermal power plant, as we know that exhaust steam from turbine goes to heat recovery unit and from there the exhaust stem goes to the condenser to condense. In shell and tube heat exchanger, cooling water as a cooling medium running inside the tubes whereas steam is inside the shell. So to have sufficient amount of cooling water, we require continuous flow of water from the cooling tower. Our main project aim is to provide a piping between condenser and cooling tower. So in this particular project, we will make basic documents such as pfd, p&id, plot plan, equipment layout, piping ga drawing, isometrics, mto, piping specifications, pump specification, calculations, and stress analysis etc.
This document discusses predicting the cold water temperature of a cooling tower under different conditions. It begins by explaining cooling tower theory and the accepted performance equation. It then shows how to calculate the tower characteristics (NTU) at design conditions using the Merkel equation. This involves calculating parameters like L/G ratio, enthalpy differences, and incremental NTU values. The example calculates the design tower characteristic (NTU) of 1.367 for a cooling tower in Mumbai with given design temperatures. It further demonstrates how to predict the new tower characteristic if the wet bulb temperature changes while other factors remain constant.
As run energy efficiency of cooling towersD.Pawan Kumar
This document discusses factors that affect the energy efficiency of cooling towers, including entering wet bulb temperature, cooling range, effectiveness, and approach temperature. It notes that simultaneous achievement of maximum range, capacity, and effectiveness with lowest input energy is desirable. The performance of cooling towers in actual operation should be assessed against design conditions and performance curves. Key factors to examine include heat load, water flow, fan power, range, and effectiveness. Optimizing factors like fan operation, cycles of concentration, drift eliminators, and load segregation can improve efficiency.
In this Thesis I will try to understand the concept associated with cooling towers and model a laboratory sized cooling tower in a software package called Engineering Equation Solver (EES). An example of system modelling is presented in this progress report, along with the comparison of a set of results with an experimental data from P.A Hilton Model H892 Bench top cooling tower with a maximum of 9% error. A user interface is also modelled to simulate off-design performance rather than conducting experiments. It also allows you to do additional scenarios that cannot be practically being done in lab,
like Relative humidity, etc.
The document discusses a seminar on studying the behavior of hyperbolic cooling tower shells with pipe openings using a 1:50 scale model subjected to seismic loads. Hyperbolic cooling towers are large reinforced concrete structures that extract heat from water to cool it. The seminar focuses on analyzing a scaled down model of a cooling tower subjected to earthquake loads. Sensors are placed on the model to measure strains and deflections under simulated seismic conditions to understand how the structure responds.
the final abstract of our major project for the award of the degree of bachel...Sourav Lahiri
Cooling towers are heat rejection devices that allow industrial processes to reuse water by cooling it through evaporation. There are several types of cooling towers based on their design and operating principles. The key types are wet cooling towers, which use direct evaporation to cool water below the ambient air temperature, and closed circuit cooling towers, which protect process water from exposure while still enabling evaporative cooling. Cooling towers have evolved from early designs like spray ponds and platform towers to modern configurations that optimize heat transfer, such as those using fill materials to increase surface area between air and water flows.
The document discusses the history and scientific development of cooling tower design theory. It begins by explaining how Merkel developed the first scientific theory for evaluating cooling tower performance in 1925. It then provides definitions of key cooling tower concepts like approach, range, and heat transfer methods. The document goes on to describe parameters like tower characteristics, fan power requirements, and water loss factors. It also summarizes Merkel's assumptions and the development of generalized supply equations from manufacturer curves.
Cooling Tower: Types and performance evaluation, Efficient system operation, Flow control strategies and energy saving opportunities, Assessment of cooling towers
This document summarizes water treatment methods for cooling towers. It discusses corrosion inhibition, scale inhibition, and bacterial control, which are the three main objectives of water treatment. For each objective, it describes the causes of problems, prevention methods, and common chemical and physical treatment methods. It also covers water treatment system controls and monitoring, occupational safety considerations, and definitions of key terms related to water treatment. The intended audience includes cooling tower owners, designers, and operators to help them properly design, operate, and maintain water treatment systems for cooling towers.
Four students designed and modeled a counter flow cooling tower for an air conditioning system with 578 ton cooling capacity. They developed a thermodynamic model based on Merkel's theory and implemented it in a computer program. Their model determined the optimal water to air mass flow ratio matched the cooling tower characteristic and packing function. Their results showed the cooling tower area increases with higher inlet air humidity and larger temperature range.
The document discusses forced draft cooling towers and their components. It describes the key parts including fans, drift eliminators, fills, nozzles, and basins. It also covers topics like packing materials, water and salt balances, windage losses, heat balances, biocides, chlorine dioxide production, and links to additional resources.
This document describes the process of how wet cooling towers function to transfer waste heat from industrial processes to the atmosphere. The warm water returns to the top of the cooling tower and trickles down over fill material, contacting an upward flow of ambient air induced by fans. This contact causes some of the water to evaporate, cooling the remaining water which is then ready to recirculate. Dissolved salts are left behind in the water, increasing its concentration, so blowdown removes some water to control the salt level while fresh makeup water is added to compensate for losses from evaporation, drift, and blowdown.
Analysis of forced draft cooling tower performance using ansys fluent softwareeSAT Journals
Abstract In this project the cooling tower performance has been analyzed by varying air inlet parameters with different air inlet angles and by attaching a nozzle in air inlet. The cooling tower analyzed here is used specifically for small scale industries, which is forced draft counter-flow cooling tower with single module capacities from 10 to 100 cooling tons. In this project 50 tons cooling capacity model has been taken as reference model. The analysis has been done using computational fluid dynamics (CFD) ANSYS 14.5 software. The cooling tower models have been modeled using SOLIDWORKS 2013 software and they have been meshed using ICEM CFD 14.5 software. The meshed models have been analyzed using FLUENT software. The air inlet angles varied in horizontal direction, vertical direction and by combining both horizontal and vertical inclination. A convergent nozzle has been modeled and assembled to the inlet pipe. The temperature contours of the cooling tower models have been taken from the analysis. Based on the outlet cold water temperature, the improved effectiveness of the cooling tower model has been obtained.
Keywords: Forced draft cooling tower, Air inlet parameter, Convergent nozzle, Cooling ton capacity, Counter flow cooling tower, Ansys 14.5, Solidworks 2013, ICEM CFD 14.5, Effectiveness of cooling tower.
This document provides a summary of the selection process for a water cooled chiller system for Comin Khmere Co. Ltd. The following key steps are described:
1) A building load calculation using HAP software determined a total cooling load of 2357 kW. This required selecting a chiller with a 843.9 kW cooling capacity and 4 chillers total.
2) A 1012.68 kW cooling tower was selected based on the chiller condenser load and design parameters.
3) Pumps were selected to move 40.4 l/s of chilled water and 48.5 l/s of condenser water, with pressure drops of 270 kPa and 280 kPa respectively accounted
This document provides an overview of cooling towers. It begins with introductions and definitions, explaining that cooling towers reject heat from condenser water to the ambient air. It then discusses cooling tower fundamentals, components, performance factors like approach and effectiveness. It outlines the heat transfer process. It describes the two main types of cooling towers: natural draft and mechanical draft. Finally, it lists several parameters for assessing cooling tower performance, such as range, approach, effectiveness, cooling capacity, and cycles of concentration.
This document is a report on a study of cooling towers conducted by five mechanical engineering students at Delhi Technological University. It provides an overview of cooling towers, including their components, materials, types, and ways to assess performance and increase energy efficiency. The two main types are natural draft towers, which use temperature differences to circulate air without fans, and mechanical draft towers, which use large fans. The report evaluates selecting the right tower, fill media effects, pumps, distribution systems, fans and more to optimize efficiency. It includes acknowledgments, objectives, figures, tables, and conclusions from the study.
A natural draft cooling tower uses convection to remove waste heat from water and release it into the atmosphere. It has no mechanical components and relies on the natural draft or stack effect to circulate air through the tower. Hot water is distributed through fill material inside the reinforced concrete shell where it comes into contact with rising ambient air, causing heat to transfer from the water to the air through evaporation and cooling the water.
This document compares the thermal performances of plate-fin and pin-fin heat sinks subject to an impinging flow. Experiments are conducted for various flow rates and channel widths to collect data on pressure drop and thermal resistance. A model is developed based on a volume averaging approach to predict these parameters. The optimized plate-fin and pin-fin heat sinks are then compared using the model. A contour map is presented showing the ratio of thermal resistances of the optimized designs as a function of dimensionless pumping power and length. The map indicates pin-fin heat sinks have lower resistance when pumping power is small and length is large, while plate-fin heat sinks perform better when pumping power is large and length is small.
Convection is the transfer of heat by the motion of liquids and gases. It occurs due to differences in density caused by temperature variations. There are two types of convection: free convection, which occurs due to natural density differences, and forced convection, where an external force circulates the fluid. The rate of convective heat transfer depends on properties of the fluid and surface, and can be calculated using empirical correlations that involve parameters like Reynolds number, Nusselt number, and Prandtl number. Boiling and condensation are specific types of phase-change heat transfer that occur at saturated temperatures. Different regimes like nucleate boiling or film boiling depend on the temperature difference between the surface and fluid.
This document discusses heat exchangers and their classification. It begins by defining a heat exchanger as equipment that transfers heat between two fluids through a separating wall. It then describes the most common type, the shell and tube heat exchanger, where one fluid flows through tubes enclosed in a shell through which the other fluid flows. The document goes on to classify heat exchangers based on their type (regenerative or recuperative), fluid flow characteristics (liquid/liquid, liquid/gas, gas/gas), and flow arrangements (counter-current, co-current, cross-flow). It also describes specific heat exchanger configurations like clustered pipe, double pipe, and shell and tube heat exchangers.
This document discusses heat exchangers and provides details on shell-and-tube heat exchangers. It describes the basic components and design of shell-and-tube heat exchangers, including tubes, tube sheets, baffles, and shells. Equations for heat transfer and thermal analysis of shell-and-tube exchangers are presented. An example problem demonstrates the design calculations to determine the required heat exchanger area and fluid flow rates.
Characterization of a cold battery with iced water and doubleAlexander Decker
This document summarizes research characterizing a cold battery that uses iced water and a double heat exchanger system in humid conditions. The cold battery uses two heat exchangers in series - a flat plate exchanger and a shell-and-tube exchanger. It is modeled in humid mode where the battery surface is cooler than the air dew point, causing condensation. Equations are provided to calculate the heat transfer between the air and condensation film, the film and water, and overall heat flux considering the heat exchangers in series. The efficiency of the battery is determined based on the individual exchanger efficiencies. Methods to determine the overall heat transfer coefficient and local heat transfer coefficients on the air side are also
This document discusses heat exchangers and includes the following key points:
- It describes different types of heat exchangers including concentric-tube, cross-flow, shell-and-tube, and compact heat exchangers.
- It discusses the overall heat transfer coefficient and factors that influence it such as convection, conduction, fins, and fouling.
- It introduces the log mean temperature difference (LMTD) method for calculating heat transfer in heat exchangers and how LMTD is evaluated for different flow configurations.
- It provides an example problem demonstrating how to determine the overall heat transfer coefficient and heat transfer rate for a heat recovery device.
This document discusses heat exchangers, including their types, performance parameters, and design methodologies. It introduces the log mean temperature difference method for relating heat transfer rate to inlet/outlet temperatures. It also describes the effectiveness-NTU method, where effectiveness is defined as the ratio of actual to maximum possible heat transfer, and NTU is the number of transfer units. Sample problems demonstrate the use of these methods to determine required surface areas, heat transfer rates, and outlet temperatures for given heat exchanger configurations and operating conditions.
Thermal rating of Shell & Tube Heat ExchangerVikram Sharma
This presentation file was created with the objective to provide a refresher course on the thermal rating of Shell and Tube heat exchanger for single-phase heat transfer
The document provides details on the design and construction of shell and tube heat exchangers. It describes the key components of a shell and tube heat exchanger including the shell, tubes, tube sheets, bonnet, channel, pass partition plates, nozzles, baffles, tie rods, and flanges. It also explains the functions of each component and provides examples of different types of components like baffles, joints between tubes and tube sheets, and impingement plates.
This document discusses different types of heat transfer via convection. It defines convection as the transfer of heat from a solid to a fluid medium. Convection is classified into natural (free) convection driven by temperature differences and forced convection using an external force. Formulas are provided for calculating heat transfer via natural convection over plates, cylinders, and spheres as well as forced convection in internal and external flows.
The document contains answers to frequently asked questions about heat transfer, listing the three main modes of heat transfer as conduction, convection, and radiation. It also provides explanations of key heat transfer terms and concepts such as baffles in shell and tube heat exchangers, factors that influence heat transfer rates, and equations that describe heat transfer mechanisms like Fourier's law of heat conduction.
This document provides details on designing a kettle reboiler to vaporize n-butane. It includes:
1) A step-by-step example design for vaporizing 5000 kg/h of n-butane using a kettle reboiler with U-tubes and steam as the heat source. Calculations are shown for required heat transfer area, boiling heat transfer coefficient, and heat exchanger effectiveness.
2) Considerations for kettle reboiler design like tube arrangement, pitch, and shell sizing based on heat flux. Equations are provided for maximum heat flux and vapor velocity.
3) General design guidelines for kettle reboilers like using a logarithmic mean
This document discusses simultaneous heat and mass transfer processes. It notes that heat conduction, mass diffusion, and fluid flow obey similar governing equations. While heat and mass transfer are mathematically analogous for gases, they are not as closely coupled for liquids due to lower mass diffusivity. The Chilton-Colburn analogy was developed based on experimental data to relate heat and mass transfer coefficients for liquids, with an exponent of 2/3. Cooling tower design examples demonstrate how heat and mass transfers are coupled in such systems.
Second sneak peak of Metal Core PCB Design webinar featuring the Thermal Management for LED Applications segment: What is the role of the PCB? by Clemens Lasance, former Principal Scientist Emeritus with Philips Research. With over 30 years experience in the field, Clemens' passion and scrutiny for the subject has established him as the principally renowned expert pertaining to thermal management.
Description af the steam generation at power plants. And a basic description of kinds of nowadays nuclear reactors. And physical basis for the calculation of boiling in the energy equipment.
Cooling of mine air by chilled water system (final)Safdar Ali
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1. HEAT REJECTION
Thomas Assaid http://benkay.net/blog/wp-content/uploads/2008/08/nuclear-
power_5810.jpg
po er 5810 jpg
Grant Welch
Jean P. Cortes
David Sobhi
3. Heat Rejection – Condenser Principles
1) Cooled water from the cooling tower at T1= 31oC.
2) Hot water to the cooling tower at T2= 41oC.
3) Steam in two-phase region (x = 0.88, P = 10kPa, 46oC) from
turbine.
turbine
4) Saturated liquid toward the nuclear reactor (x = 0, P = 10kPa)
∞ heat capacity due to phase change T and P do not change.
3)
2)
1)
4)
Condenser single-pass counter-flow shell-and-tube HX.
*higher effectiveness then the parallel-flow of similar type*
Note:
Shell-and-tube heat exchanger, Ref. [1]
HX = heat exchanger
4. Heat Rejection – Condenser Analysis
Calculate the h for the steam side and the water side.
Re, Pr,
Re Pr and Nu number of the two flows.
flows
internal flow.
Water side
external flow across tube bundles.
Steam side
These numbers change with respect to geometric variables of HX itself
• Diameter of the tubes
• Number of tubes
• Number of condensers
NTU method:
Note:
h = convective heat transfer coefficient
HX = heat exchanger
5. Condenser- MathCAD calculations
The final design for the condenser is two single-
single
pass counter-flow shell-and-tube HX in parallel.
The dimensions for each:
• 15,000 1.5” schedule 40 tubes.
• 24 7 meter long tubes with one diameter between tubes in the
24.7
staggered arrangement.
• 8.1 meter diameter shell.
• 48 000 k / of cooling water.
48,000 kg/s f li t
• Less than 10oC temperature rise.
Staggered alignment of the tube bundle, Ref. [4]
6. Heat Rejection - Cooling Tower (CT)
• Evaporative cooling tower Natural draft
draft.
• Direct counter-flow contact and mass transfer
between moist air and hot water
water.
Water will transfer heat/energy to the surrounding air
(evaporation of small portion of water due to latent heat )
then water will cool down.
Air will be heated and humidified by the sprayed-hot water
coming from the condenser.
g
• This cooled water will work as coolant for our
condenser.
7. Heat Rejection – CT Principles
Qrejected (heated air out)
Drift
eliminators
Splash-type
fill packing
Hot
Spray water
distribution
Air in
Air in
Film-type
fill packing
Cold
water
Schematic representation of a counter flow cooling
tower depicted from ASHRAE. Systems and
Equipment 1996, pp. 36.2,36.3
8. Heat Rejection – CT Analysis
Detailed Analysis iteration solution, trial and error
solution
procedure, or graphical solution.
Schematic diagram of
1) From the energy balance between air counterflow cooling tower
g
and water at dV element,
2) Water energy balance in terms of the
heat- and mass-transfer coefficients,
heat mass transfer
hc and hD; and substituting
Le = hc/hD*cpa
3) Air-side water-vapor mass balance
Note:
W = humidity ratio.
h = enthalpy
hs,w enthalpy of saturated moist air evaluated at tw
ma = mA= mass of the moist air.
AV= area of the splash-type packing
9. Heat Rejection – CT Analysis
W
Conclusion: the minimum Twater leaving the
cooling tower would be the Twet-bulb_air_in
t b lb i i
T
NTU method Graphical solution on the psychrometric chart.
CT effectiveness (ε) = ratio of actual energy transferred to the maximum possible
energy transfer units for the fluid with minimum capacity rate. Assuming minimum
t f it f th fl id ith i i it tA i ii
evaporation and Le = 1
The error can be reduced by using two or more increments rather than one. As
more increments are considered, the assumption of a linear relationship
between saturated moist air enthalpy and temperature becomes more exact.
10. Cooling Tower- Final Design
The final design for the cooling tower is the natural draft
type.
The dimensions are:
• 9971 m3 volume of splash type packing.
• 1.9 m of the packing height .
• 80 m diameter of packing fill.
• 18,750 kg/s of moist air.
• ΔT = 10oC of water
water.
• Approximately 120 m tall hyperbolic design.
11. Pumping and piping calculations
The final design for pumping system :
• 2 Pumps to the condenser,
Power: 18 MW
Head loss: 32 m
Mass flow rate: 48000 kg/s
• 2 Pumps to the makeup water:
Power: < 100 KW
Head loss:3 m
Mass flow rate: 2400 kg/s
g
The final design for piping network:
• Diameter: 2.5 m
• Transport pipe total length: 800 m
Total length from the pump to the condenser: 200 m
Total length from the condenser to the cooling tower: 200 m
Note:
Pumps are Vertical Wet Pit from Goulds Pumps
Pipes: mild steel.
13. Environmental Impact
Environmental Impact:
Environmental impact can be briefly described in two categories:
• Harmful usage effects on the environment such as natural resource p
g pollution.
• Performance efficiency reduction due to the surroundings such as fouling,
corrosion and drift.
Design and operating considerations related to the environmental impact:
g g
•In air conditioning installations with the experience of Legionella, it is now
mandatory to keep a working log as well as a record of hygiene testing to
determine non existence of bacteria.
•Cooling tower water treatment by chlorine dosing is recommended by certain
local authorities.
•Close checks should be kept on the overall system and extra cleaning of the
tower pack and distribution system should be taken under such circumstance
p y
where gusty conditions by windage or blow-out from the air inlets or by outside
influences
14. Economic and Budget
Cost Estimate:
•The estimated purchase cost value of the cooling tower
was determined to be 13.4 million USD using the volumetric
flow rate (GPM) of the cooled water, and assuming liner
interpolation of the cost estimate curve.
•The estimated purchase cost value of all the equipments in
p qp
the heat rejection system was determined to be 136 million
USD.
• The operational cost was determined to be 462.35 million
USD.
•Including direct costs, indirect costs, and 43% overhead
Including costs costs
costs, the total cost of the entire systems was determined
to be 1.04 billion USD
15. Heat Rejection - Conclusion and Recommendations
Component Strength Weakness
Condenser High effectiveness and NTU. Larger overall volume than a
cross flow fin and tube heat
Two condensers, so if needed
exchanger
the plant can still operate
while one is worked on.
Cooling tower Most reliable compared to To build it is expensive
other t
th types of cooling t
f li towers.
Low operating costs
Pumps Small amount of head loss due Large pump power due to the
to parallel system high mass flow rate of the
system
Condenser:
• Split it up for iterative solution solving for the h as the xsteam changes
• Parametric analysis should include:
• Type of material used for the tubes .
• Tube spacing and thickness.
Cooling tower:
• Develop a detailed analysis and compare the NTU method.
• Set up an iterative solution that will calculate for the variable
diameter.
• Develop a means of calculating the packing mass transfer coefficient
instead of assuming one.