Maximizing Plant Power Output Using Dry Cooling System

2004 ◽  
Author(s):  
Ram Chandran
Keyword(s):  
Power Output ◽  
Cooling System ◽  
Combined Cycle ◽  
Ambient Temperatures ◽  
Turbine Efficiency ◽  
The Cost ◽  
The Impact ◽  
Lower Plant ◽  
Plant Power ◽  
Dry Cooling

As the power industry is deregulated, the cost of power plays a major role in obtaining long-term Power Purchase agreements. More and more plants, now, are developed with Dry Cooling System for condensing steam from the steam turbine of combined cycle plants or coal-fired plants. However, Dry Cooling has become synonymous with lower plant output. This paper presents solutions to dispel that myth. 1. Options available for control of the air-cooled system, their initial cost and the impact on minimizing internal power consumption and maximizing plant power output. 2. The air-cooled condenser operates normally at high turbine exhaust pressures during high ambient temperatures. The high backpressure results in lower turbine efficiency and lower plant output. Various options available are presented to combat this deficiency to maximize power output.

Inlet Air Cooling Applied to Combined Cycle Power Plants: Influence of Site Climate and Thermal Storage Systems

2008 ◽  
Vol 130 (2) ◽  
Author(s):  
Nicola Palestra ◽  
Giovanna Barigozzi ◽  
Antonio Perdichizzi
Keyword(s):  
Power Output ◽  
Parametric Analysis ◽  
Power Plants ◽  
Cooling System ◽  
Thermal Storage ◽  
Combined Cycle ◽  
Operating Conditions ◽  
Air Cooling ◽  
Ambient Conditions ◽  
Cooling Systems

The paper presents the results of an investigation on inlet air cooling systems based on cool thermal storage, applied to combined cycle power plants. Such systems provide a significant increase of electric energy production in the peak hours; the charge of the cool thermal storage is performed instead during the night time. The inlet air cooling system also allows the plant to reduce power output dependence on ambient conditions. A 127MW combined cycle power plant operating in the Italian scenario is the object of this investigation. Two different technologies for cool thermal storage have been considered: ice harvester and stratified chilled water. To evaluate the performance of the combined cycle under different operating conditions, inlet cooling systems have been simulated with an in-house developed computational code. An economical analysis has been then performed. Different plant location sites have been considered, with the purpose to weigh up the influence of climatic conditions. Finally, a parametric analysis has been carried out in order to investigate how a variation of the thermal storage size affects the combined cycle performances and the investment profitability. It was found that both cool thermal storage technologies considered perform similarly in terms of gross extra production of energy. Despite this, the ice harvester shows higher parasitic load due to chillers consumptions. Warmer climates of the plant site resulted in a greater increase in the amount of operational hours than power output augmentation; investment profitability is different as well. Results of parametric analysis showed how important the size of inlet cooling storage may be for economical results.

Evaluating the Impact of the Uncertainty of Evaporative Cooler Effectiveness on the Net Power for a PTC 46 Test

2010 ◽  
Author(s):  
Matthew J. Dooley
Keyword(s):  
Relative Humidity ◽  
Power Output ◽  
Combined Cycle ◽  
Performance Guarantees ◽  
K Factor ◽  
Evaporative Cooler ◽  
The Impact

This paper discusses how relative humidity impacts the effectiveness of an evaporative cooler, the uncertainty of the calculated effectiveness and the corresponding impact of the limits of this uncertainty on the power output. This is particularly related to a combined cycle facility where performance guarantees are based upon the evaporative cooler being in service. Different options for testing with and without the evaporative cooler in service are discussed as well as the need for an uncertainty when using a K factor.

Hybrid Cooling for Thermal-Electric Power Generation

2013 ◽  
Author(s):  
John S. Maulbetsch
Keyword(s):  
Cooling System ◽  
Meteorological Data ◽  
Combined Cycle ◽  
Plant Performance ◽  
Design Parameters ◽  
Water Requirements ◽  
Cooling Systems ◽  
Capital Costs ◽  
Hybrid Cooling ◽  
Dry Cooling

Water use by power plant cooling systems has become a critical siting issue for new plants and the object of increasing pressure for modification or retrofit at existing plants. Wet cooling typically costs less and results in more efficient plant performance. Dry cooling, while costing more and imposing heat rate and capacity penalties on the plant, conserves significant amounts of water and eliminates any concerns regarding thermal discharge to or intake losses on local water bodies. Hybrid cooling systems have the potential of combining the advantages of both systems by reducing, although not eliminating, water requirements while incurring performance penalties that are less than those from all-dry systems. The costs, while greater than those for wet cooling, can be less than those for dry. This paper addresses parallel wet/dry systems combining direct dry cooling using a forced-draft air-cooled condenser (ACC) with closed-cycle wet cooling using a surface (shell-and-tube) steam condenser and a mechanical-draft, counterflow wet cooling tower as applied to coal-fired steam plants, gas-fired combined-cycle plants and nuclear plants. A brief summary of criteria used to identify situations where hybrid systems should be considered is given. A methodology for specifying and selecting a hybrid system is described along with the information and data requirements for sizing and estimating the capital costs and water requirements a specified plant at a specified site. The methodology incorporates critical plant and operating parameters into the analysis, such as plant monthly load profile, plant equipment design parameters for equipment related to the cooling system, e.g. steam turbine, condenser, wet or dry cooling system, wastewater treatment system. Site characteristics include a water budget or constraints, e.g. acre feet of water available for cooling on an annual basis as well as any monthly or seasonal “draw rate” constraints and meteorological data. The effect of economic parameters including cost of capital, power, water and chemicals for wastewater treating are reviewed. Finally some examples of selected systems at sites of varying meteorological characteristics are presented.

An analysis of the impact of draft tube modifications on the performance of a Kaplan turbine by means of computational fluid dynamics

2017 ◽  
Vol 232 (11) ◽  
pp. 1937-1952
Author(s):  
Juergen Schiffer ◽  
Helmut Benigni ◽  
Helmut Jaberg
Keyword(s):  
Fluid Dynamics ◽  
Computational Fluid Dynamics ◽  
Draft Tube ◽  
Vertical Axis ◽  
Hydropower Plant ◽  
Construction Costs ◽  
Turbine Efficiency ◽  
Kaplan Turbine ◽  
The Cost ◽  
The Impact

Due to the low electricity prices in central Europe, cost optimisations related to all parts of a new hydropower plant have become increasingly important. In case of a run-of-river hydropower plant using a vertical axis Kaplan turbine, one of the cost drivers are the excavation works. Thus, a decisive factor for the reduction of construction costs is the minimisation of the construction depth of the elbow-type draft tube. In course of the design phase of a new hydropower plant in Austria, an analysis of the impact of draft tube modifications on the performance of the Kaplan turbine was carried out by applying computational fluid dynamics. The net head of the turbine with a diameter of D = 3.15 m accounts for Hnet = 9.00 m and the maximum discharge per unit is Qmax = 57.5 m3/s. After it was proven that there is a good agreement of the numerically calculated and experimentally measured turbine efficiency for the original turbine configuration, various draft tube designs were tested in order to find out their impact on the turbine efficiency and to analyse the sources of draft tube losses in detail. Finally, it was possible to find a new draft tube design representing a compromise of reduced construction costs and acceptable turbine efficiency.

Economic Design of Hybrid Wet-Dry Cooling Systems

2013 ◽  
Author(s):  
R. W. Card
Keyword(s):  
Power Plants ◽  
Cooling System ◽  
Combined Cycle ◽  
Weather Data ◽  
Net Generation ◽  
Steam Turbines ◽  
Cooling Systems ◽  
Hybrid Cooling ◽  
Seasonal Basis ◽  
Dry Cooling

A hybrid wet-dry cooling system can be designed for a large combined-cycle power plant. A well-designed hybrid cooling system will provide reasonable net generation year-round, while using substantially less water than a conventional wet cooling tower. The optimum design for the hybrid system depends upon climate at the site, the price of power, and the price of water. These factors vary on a seasonal basis. Two hypothetical power plants are modeled, using state-of-the-art steam turbines and hybrid cooling systems. The plants are designed for water-constrained sites incorporating typical weather data, power prices, and water prices. The principles for economic designs of hybrid cooling systems are demonstrated.

Towards a Technoeconomic Framework for Estimating Cost-Performance Tradeoffs for Power Plants Incorporating Transformative Dry-Cooling Technologies

2016 ◽  
Author(s):  
Geoffrey Short ◽  
Addison K. Stark ◽  
Daniel Matuszak ◽  
James F. Klausner
Keyword(s):  
Heat Transfer ◽  
Power Plant ◽  
Fresh Water ◽  
Power Plants ◽  
Cooling System ◽  
Combined Cycle ◽  
Cooling Systems ◽  
Natural Gas Combined Cycle ◽  
Evaporative Cooling System ◽  
Dry Cooling

Fresh water withdrawal for thermoelectric power generation in the U.S. is approximately 139 billion gallons per day (BGD), or 41% of total fresh water draw, making it the largest single use of fresh water in the U.S. Of the fresh water withdrawn for the power generation sector, 4.3 BGD is dissipated to the atmosphere by cooling towers and spray ponds. Dry-cooled power plants are attractive and sometimes necessary because they avoid significant withdrawal and consumption of freshwater resources that could otherwise be used for other purposes. This could become even more important when considering the potential effects of climate change (1). Additional benefits of dry-cooling include power plant site flexibility, reduced risk of water scarcity, and faster permitting (reducing project development time and cost). However, dry-cooling systems are known to be more costly and larger than their wet-cooling counterparts. Additionally, without the benefit of additional latent heat transfer through evaporation, the Rankine cycle condensing (cold) temperature for dry-cooling is typically higher than that for wet-cooling, affecting the efficiency of power production and the resultant levelized cost of electricity (LCOE). The Advanced Research Projects Agency - Energy (ARPA-E) has developed a technoeconomic analysis (TEA) model for the development of indirect dry-cooling systems employing steam condensation within a natural gas combined cycle power plant. The TEA model has been used to inform the Advanced Research in Dry-Cooling (ARID) Program on the performance metrics needed to achieve an economical dry-cooling technology. In order to assess the relationship between air-cooled heat exchanger (ACHX) performance, including air side heat transfer coefficient and pressure drop, and power plant economics, ARPA-E has employed a modified version of the National Energy Technology Laboratory (NETL) model of a 550 MW natural gas combined cycle (NGCC) plant employing an evaporative cooling system. The evaporative cooling system, including associated balance of system costs, was replaced with a thermodynamic model for an ACHX with the desired improved heat transfer performance and supplemental cooling and storage systems. Monte Carlo simulation determined an optimal ACHX geometry and associated ACHX cost. Allowing for an increase in LCOE of 5%, the maximum allowable additional cost of the supplemental cooling system was determined as a function of the degree of cooling of the working fluid required. This paper describes the methodologies employed in the TEA, details the results, and includes related models as supplemental material, while providing insight on how the open source tool might be used for thermal management innovation.

Combined-Cycle Power Plants From Gas Turbines and Geothermal Source Integration

1993 ◽  
Author(s):  
R. Bettocchi ◽  
G. Cantore ◽  
G. Negri di Montenegro ◽  
A. Peretto ◽  
E. Gadda
Keyword(s):  
Power Output ◽  
Gas Turbines ◽  
Power Plants ◽  
High Efficiency ◽  
Combined Cycle ◽  
Point Of View ◽  
Total Power ◽  
Geothermal Fluid ◽  
Exhaust Gases ◽  
Plant Power

Geothermal power plants have difficulties due to the low conversion efficiencies achievable. Geothermal integrated combined cycle proposed and analyzed in this paper is a way to achieve high efficiency. In the proposed cycle the geothermal fluid energy is added, through suitable heat ecxhangers, to that of exhaust gases for generating a steam cycle. The proposed cycle maintains the geothermal fluid segregated from ambient and this can be positive on the environmental point of view. Many systems configurations, based on this possibility, can be taken into account to get the best thermodynamic result. The perfomed analysis examines different possible sharings between the heat coming from geothermal and exhaust gases, and gives the resulting system efficiencies. Various pressures of the geothermal steam and water dominated sources are also taken into account. As a result the analysis shows that the integrated plant power output is largely greater than the total power obtained by summing the gas turbine and the traditional geothermal plant power output, considered separately.

Incremental Cost of CO2 Reduction in Power Plants

2002 ◽  
Author(s):  
Ram G. Narula ◽  
Harvey Wen ◽  
Kenneth Himes
Keyword(s):  
Incremental Cost ◽  
Co2 Emissions ◽  
Power Plants ◽  
Alternative Fuels ◽  
Co2 Reduction ◽  
Combined Cycle ◽  
Co2 Removal ◽  
Integrated Gasification Combined Cycle ◽  
The Cost ◽  
The Impact

Carbon dioxide (CO2) emissions from fossil-fueled power plants contribute to more than one-third of all CO2 emissions in the U.S. [1]. Any effort to curtail greenhouse gases should therefore include the reduction of this emission source. Methods of CO2 reduction include (1) use of alternative fuels with lower CO2 emissions and (2) CO2 scrubbing and sequestration to prevent its release to the atmosphere. The cost of CO2 reduction varies with the selected technology. This paper compares (1) the cost of electricity (COE) without and with CO2 removal/avoidance and (2) the impact of the incremental cost of CO2 reduction on COE for different technology options, including replacing existing coal plants with natural-gas-fired combined cycle (NGCC), integrated gasification combined cycle (IGCC) with and without CO2 removal, pulverized coal (PC) with CO2 scrubber, and nuclear plants. Full and partial compliance with the Kyoto Protocol are addressed.

HRSGs for Combined Cycle Plants: Design Considerations and Life Consumption Estimation Using Dynamic Software

2011 ◽  
Author(s):  
Suichu Sun ◽  
Akber Pasha
Keyword(s):  
Economic Benefits ◽  
Combined Cycle ◽  
Operating Conditions ◽  
Damage Mechanisms ◽  
Start Up ◽  
On Line ◽  
Critical Components ◽  
Life Consumption ◽  
The Impact ◽  
Plant Power

Today’s Heat Recovery Steam Generators are exposed to more severe operation than just running at a base load. The deregulation of the electric generation industry has resulted in an increase of merchant plants that are required to supply electrical power to the grid as needed and when needed. The plants will be coming on line with minimal notice. This puts a strain on the HRSG and unless properly designed and operated to withstand the quick start-ups and shut downs, the integrity will be compromised. Fast starts result in achieving full load revenues much sooner including the cost of high start-up emission reduction. Basic definition of a fast start is to have about 66% of the plant power available in 30–50 minutes and full plant power available in 60–75 minutes with a hot or warm steam turbine. This paper describes various mechanisms which affect the integrity of the boilers. These include the damage mechanisms, their effect on various parts and how to control them. The causes and the end results of these damage mechanisms are not the same for all components of the boiler. This analysis results in deciding which components need further review of the critical components. Detailed analysis of the critical components under the specified operating conditions can lead the nature and origin of the forces causing adverse impact on the life of the component. Once the failure mechanism is determined, means to eliminate or reduce the impact can be developed. This paper also describes the Life Consumption Estimation software which uses the data directly retrieved from the plant data acquisition system, thus eliminating the tedious task of manual data transmission. Based on the correlations developed by Vogt Power International Inc. (VPI) with the detailed dynamic simulation, Finite Element Analysis and various codes the component consumption is estimated and displayed with the calculated replacement and start-up costs on a continual basis. This gives the plant owners and operators an on line tool to gauge the economic benefits of the aggressive operations in real time.

Consideration of the Environmental Impact of Wet vs Dry Cooling for Combined Cycle Power Plants

2014 ◽  
Author(s):  
A. G. Howell
Keyword(s):  
Environmental Impact ◽  
Power Plants ◽  
Combined Cycle ◽  
Regulatory Agencies ◽  
Cooling Systems ◽  
Increasing Trend ◽  
Carbon Dioxide Co2 ◽  
The Impact ◽  
Dry Cooling ◽  
Selection Of

Combined cycle power plants fueled with natural gas have been increasingly preferred by regulatory agencies for new power generation projects, compared with traditional coal-fired plants. With growing concerns about water resource availability and the environmental impact of wet cooling systems, there has been an increasing trend for new combined cycle projects to incorporate dry cooling, often as a mandate for regulatory approval of the project. There appears to be little consideration given to the impact of less efficient dry cooling systems on unit efficiency, and particularly on increased fuel requirements and therefore carbon dioxide (CO2) emissions for a given power generating output. The trade-off between reduction of water use and increased fuel requirements with dry cooling should be included as part of the decision on the selection of cooling systems for new fossil plant construction.

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