An Estimation of the Performance Limits of Dry Cooling on Trough-Type Solar Thermal Plants

2008 ◽  
Author(s):  
Huifang Deng ◽  
Robert F. Boehm
Keyword(s):  
Power Plants ◽  
High Efficiency ◽  
Cooling System ◽  
Low Cost ◽  
Performance Limits ◽  
Cooling Systems ◽  
Solar Power Plants ◽  
Solar Resource ◽  
Dry Cooling ◽  
The Ideal

The southwestern US is an ideal location for solar power plants due to its abundant solar resource, while there is a difficulty in implementing wet cooling systems due to the shortage of water in this region. Dry cooling could be an excellent solution for this, if it could achieve a high efficiency and low cost as wet cooling. Some dry cooling systems are currently in operation, and investigations of their performance have been reported in the literature. This paper looks into the limits to the power production implicit in dry cooling, assuming that improvements might be made to the system components. Use of higher performance heat transfer surfaces is one such possible improvement. We have developed a model of a fairly typical, but simplified, solar trough plant, and simulated thermodynamic performance of this with the software Gatecycle. We have examined the power generation and cycle efficiency of the plant for the Las Vegas vicinity with conventional wet cooling and conventional dry cooling cases considered separately using this software. TMY2 data are used for this location for this purpose. Similarly, the same studies are carried out for “ideal” cooling systems as a comparison. We assumed that in the ideal dry cooling system, the condensing temperature is the ambient dry bulb temperature, and in the ideal wet cooling system, it is the ambient wet bulb temperature. It turned out that the ideal dry cooling system would significantly outperform the conventional wet cooling system, indicating the possibility of the dry cooling system being able to achieve increased performance levels with component improvements.

scholarly journals Studying the Reduction of Water Use in Integrated Solar Combined-Cycle Plants

2019 ◽  
Vol 11 (7) ◽  
pp. 2085 ◽  
Author(s):  
Fontina Petrakopoulou ◽  
Marina Olmeda-Delgado
Keyword(s):  
Water Consumption ◽  
Power Plants ◽  
High Efficiency ◽  
Cooling System ◽  
Combined Cycle ◽  
Special Focus ◽  
Cooling Systems ◽  
Cooling Fluid ◽  
Hybrid Cooling ◽  
Dry Cooling

With vast amounts of water consumed for electricity generation and water scarcity predicted to rise in the near future, the necessity to evaluate water consumption in power plants arises. Cooling systems are the main source of water consumption in thermoelectric power plants, since water is a cooling fluid with relatively low cost and high efficiency. This study evaluates the performance of two types of power plants: a natural gas combined-cycle and an integrated solar combined-cycle. Special focus is made on the cooling system used in the plants and its characteristics, such as water consumption, related costs, and fuel requirements. Wet, dry, and hybrid cooling systems are studied for each of the power plants. While water is used as the cooling fluid to condense the steam in wet cooling, dry cooling uses air circulated by a fan. Hybrid cooling presents an alternative that combines both methods. We find that hybrid cooling has the highest investment costs as it bears the sum of the costs of both wet and dry cooling systems. However, this system produces considerable fuel savings when compared to dry cooling, and a 50% reduction in water consumption when compared to wet cooling. As expected, the wet cooling system has the highest exergetic efficiency, of 1 and 5 percentage points above that of dry cooling in the conventional combined-cycle and integrated solar combined-cycle, respectively, thus representing the lowest investment cost and highest water consumption among the three alternatives. Hybrid and dry cooling systems may be considered viable alternatives under increasing water costs, requiring better enforcement of the measures for sustainable water consumption in the energy sector.

scholarly journals Towards the Development of a Low-Cost Irradiance Nowcasting Sky Imager

2019 ◽  
Vol 9 (6) ◽  
pp. 1131 ◽  
Author(s):  
Luis Valentín ◽  
Manuel Peña-Cruz ◽  
Daniela Moctezuma ◽  
Cesar Peña-Martínez ◽  
Carlos Pineda-Arellano ◽  
...  
Keyword(s):  
Solar Irradiance ◽  
Power Plants ◽  
Solar Power ◽  
Detection System ◽  
Low Cost ◽  
Resource Assessment ◽  
The Sun ◽  
Robust Detection ◽  
Solar Power Plants ◽  
Solar Resource

Solar resource assessment is fundamental to reduce the risk in selecting the solar power-plants’ location; also for designing the appropriate solar-energy conversion technology and operating new sources of solar-power generation. Having a reliable methodology for solar irradiance forecasting allows accurately identifying variations in the plant energy production and, as a consequence, determining improvements in energy supply strategies. A new trend for solar resource assessment is based on the analysis of the sky dynamics by processing a set of images of the sky dome. In this paper, a methodology for processing the sky dome images to obtain the position of the Sun is presented; this parameter is relevant to compute the solar irradiance implemented in solar resource assessment. This methodology is based on the implementation of several techniques in order to achieve a combined, fast, and robust detection system for the Sun position regardless of the conditions of the sky, which is a complex task due to the variability of the sky dynamics. Identifying the correct position of the Sun is a critical parameter to project whether, in the presence of clouds, the occlusion of the Sun is occurring, which is essential in short-term solar resource assessment, the so-called irradiance nowcasting. The experimental results confirm that the proposed methodology performs well in the detection of the position of the Sun not only in a clear-sky day, but also in a cloudy one. The proposed methodology is also a reliable tool to cover the dynamics of the sky.

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.

scholarly journals Economic Analysis of a Zero-Water Solar Power Plant for Energy Security

2021 ◽  
Vol 11 (20) ◽  
pp. 9639
Author(s):  
Eduardo de la Rocha Camba ◽  
Fontina Petrakopoulou
Keyword(s):  
Power Plant ◽  
Energy Security ◽  
Power Plants ◽  
Net Present Value ◽  
Solar Power ◽  
Cooling System ◽  
Solar Power Plant ◽  
Levelized Cost Of Electricity ◽  
Cooling Systems ◽  
Dry Cooling

Water dependency of power plants undermines energy security by making power generation susceptible to water scarcity. This study evaluates the economic performance of a novel dry-cooling system for a water-independent solar power plant. The proposed cooling system is based on the concept of earth–air heat exchangers, approaching zero environmental impact. The viability of the proposed design is discussed based on both costs and benefits, and it is compared to both conventional dry- and wet-cooling systems. The installation costs of the plant are found to be EUR 13,728/kW, resulting in the substantial levelized cost of electricity of EUR 505.97/MWh. The net present value of the studied design assuming a water-cost saving of EUR 1/m3 is found to be MEUR –139.59. Significantly higher water prices in the future might eventually make the proposed system economically attractive when compared to water-cooling systems. However, the new system would require drastic modifications to become more attractive when compared to existing dry-cooling systems. Specific possibilities to improve it for zero-water use in thermoelectric power plants are further discussed.

scholarly journals Investigation of Thermo-Flow Characteristics of Natural Draft Dry Cooling Systems Designed with Only One Tower in 2 × 660 MW Power Plants

Energies ◽  
2021 ◽  
Vol 14 (5) ◽  
pp. 1308
Author(s):  
Mohan Liu ◽  
Lei Chen ◽  
Kaijun Jiang ◽  
Xiaohui Zhou ◽  
Zongyang Zhang ◽  
...  
Keyword(s):  
Heat Transfer ◽  
Power Plants ◽  
Cooling System ◽  
Flow Characteristics ◽  
Cooling Systems ◽  
Natural Draft ◽  
Wind Speeds ◽  
Flow And Heat Transfer ◽  
Power Load ◽  
Dry Cooling

In recent years, natural draft dry cooling systems with only one tower have been adopted in some 2 × 660 MW power-generating units owing to the advantage of lower construction costs. The operating cases of two power-generating units and one power-generating unit will both appear based on the power load requirement, which may lead to very different flow and heat transfer performances of this typical cooling system. Therefore, this research explores the local thermo-flow characteristics of air-cooled heat exchangers and sectors, and then analyzes the overall cooling performance of the above two operating cases under various wind conditions. Using the numerical modeling method, the results indicate that the flow and heat transfer performance of this cooling system decreases significantly in the case of one unit with half sectors dismissed. At wind speeds lower than 8 m/s, the difference in turbine back pressure between two units and one unit appears obviously higher than in other wind conditions, even reaching 4.37 kPa. Furthermore, the air-cooled heat exchanger in the lower layer always has better cooling capability than that in the upper layer, especially in conditions where there is an absence of wind and under low wind speeds. The operating case of one unit is not recommended for this dry cooling system because of the highly decreased energy efficiency. In conclusion, this research could provide theoretical support for the engineering operation of this typical natural draft dry cooling system in 2 × 660 MW power plants.

scholarly journals Improving the cooling system of ship equipment

2020 ◽  
Author(s):  
А.В. Фомин ◽  
Е.В. Фомин
Keyword(s):  
Power Plants ◽  
High Efficiency ◽  
Cooling System ◽  
Heat Removal ◽  
Normal Operation ◽  
Water Cooling ◽  
Cooling Systems ◽  
Start Up ◽  
Membrane Type ◽  
Water Cooling System

В статье представлены результаты исследования эффективности работы системы охлаждения корабельного оборудования и предложены конструктивные решения, позволяющие модернизировать данную систему. В настоящее время, для обеспечения нормальной работы корабельного оборудования, применяются системы охлаждения. В корабельных энергетических установках распространены системы водяного охлаждения из-за целого ряда преимуществ. К ним относится и высокая эффективность теплоотвода, и меньшее влияние внешней среды, а также более надежный пуск и возможность использования энергии отводимого тепла для других нужд. Одним из основных элементов в таких системах является расширительный бак гравитационного типа, обеспечивающий правильную циркуляцию дистиллированной воды во внутреннем контуре и расположенный в верхней точке системы. Однако практика испытаний и эксплуатации показала, что есть и серьезный недостаток в таком расположении бака – в случаи его перелива или разрыва может пострадать дорогостоящее оборудование, расположенное ниже. В связи с этим, определены направления по совершенствованию системы водяного охлаждения корабельного оборудования, которые связаны с применением расширительного бака мембранного типа и использования воздухоудаляющих клапанов. The article presents the results of a study of the efficiency of the cooling system of ship equipment and offers design solutions that allow to modernize this system. Currently, to ensure the normal operation of ship's equipment, cooling systems are used. Water cooling systems are common in ship power plants due to a number of advantages. These include high efficiency of heat removal, less influence of the external environment, as well as more reliable start-up and the ability to use the energy of the heat being withdrawn for other needs. One of the main elements in such systems is a gravity-type expansion tank that ensures proper circulation of distilled water in the internal circuit and is located at the top of the system. However, the practice of testing and operation has shown that there is a serious drawback in this arrangement of the tank – in cases of overflow or rupture, expensive equipment located below may suffer. In this regard, the directions for improving the water cooling system of ship equipment, which are associated with the use of an expansion tank of the membrane type and the use of air-removing valves, have been identified.

Technoeconomic Optimization of Turbocompression Cooling Systems

2017 ◽  
Author(s):  
Spencer C. Gibson ◽  
Derek Young ◽  
Todd M. Bandhauer
Keyword(s):  
Heat Exchangers ◽  
Power Plants ◽  
High Efficiency ◽  
Waste Heat ◽  
Cooling System ◽  
Payback Period ◽  
Low Grade ◽  
Air Cooling ◽  
Total System ◽  
Cooling Systems

Low grade waste heat streams with temperatures near 100°C are abundant, presenting a significant opportunity to reduce primary energy consumption across the world. For example, thermally activated cooling systems can utilize waste heat to meet air conditioning loads. Recently, a turbocompression cooling system (TCCS) that utilizes low grade waste heat from power plants was investigated to improve the economic viability of dry air cooling systems. The TCCS utilizes Rankine and vapor-compression cycles that are directly coupled through a high efficiency centrifugal turbine and a compressor. In this paper, a coupled thermodynamic, heat transfer, and economic model for a TCCS is applied to utilizing low grade engine coolant waste heat to meet cargo ship cooling load requirements while minimizing the payback period for a particular operational scenario. The results of this study show that with a constant heat input of 2 MW, the liquid coupled turbocompression cooling system provided 642 kW of cooling with a payback period of 2 years and 6 months, and the total cost of the heat exchangers made up more than 84% of the total system cost. In addition, a sensitivity analysis showed that the effectiveness of the power cycle heat exchangers have a stronger influence on the payback period than the cooling cycle heat exchangers.

Performance Testing of Hybrid Wet-Dry Cooling Systems: Insights From Numerical Modeling

2014 ◽  
Author(s):  
R. W. Card
Keyword(s):  
Water Conservation ◽  
Power Plants ◽  
Performance Test ◽  
Cooling System ◽  
Performance Testing ◽  
Cooling Systems ◽  
Effective Performance ◽  
Performance Penalty ◽  
Dry Cooling ◽  
Turbine Exhaust

A hybrid wet-dry cooling system can reduce water consumption at a power plant while minimizing the performance penalty of an air-cooled condenser (ACC). Automatic allocation of turbine exhaust steam among the wet and dry sections provides robust performance. However, the performance test for the unit must be carefully designed to prove the guarantees for water conservation and thermal performance with minimal uncertainty. A hybrid wet-dry cooling system of the “parallel” type is modeled based on recently-constructed power plants. Effects of typical off-design test conditions are demonstrated. Techniques are recommended for designing an effective performance test for a hybrid wet-dry cooling system based on the use of existing Performance Test Codes (PTC).

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.

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