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A theoretical and experimental investigation into the thermodynamic performance of a 50 MW power plant with a novel modular air-cooled condenser
... The need to conserve available water resources, which drives the wet cooling technology, has elicited interest in the deployment of alternative cooling technologies, such as dry cooling systems. The installation of air-cooled condensers (ACC) in thermoelectric power plants has increased significantly in the past few decades, and this trend is projected to grow in future [10][11][12]. The dry cooling systems offer potential environmental benefits by the ability to achieve over 90% savings in water resources and plant sitting flexibility [12,13]. ...
... To improve the performance of the air-cooled condenser to be more competitive with its wet cooling counterpart, several design modifications and operating strategies have been proposed. O'Donovan and Grimes [11] presented the design, testing and simulation results of a modular air-cooled condenser with variable speed fans to respond to variations in ambient air conditions and maintain optimum plant performance. Li et al. [20] identified optimal fan operating frequency ranges for the improvement of air-cooled plant performance under varying ambient temperature ranges (10 • C-30 • C) and off-design load conditions. ...
... It can be observed that as the ambient dry-bulb temperature increased along with the wet-bulb temperature, the steam condensing temperature increased but with a significant drop in the turbine power output. Conventionally, steam condenser cooling systems are designed for a particular ambient temperature, thus limiting the ability of current steam condensation system designs to respond to variations of ambient temperature [11]. Imperatively, the development of variable steam condensation -ambient temperature charts would help in the improvement of the dynamic performance characteristics of steam cycle power plants. ...
For combined-cycle power plants, the two most dominant steam condenser cooling options are the wet-cooling tower and the air-cooled (dry) systems. The wet cooling system is commonly installed on plants located in areas with available water sources, while the dry system is typically preferred in areas where water is scarce. However, owing to the increasing regulations on water conservation, water usage costs and improvements on cooling system designs, a new approach is required for the optimal selection of plant cooling systems, incorporating site climatic conditions, amongst other considerations. This study presents a comparative techno-economic analysis of a steam turbine cycle with wet-and dry-cooling systems for five typical tropical locations in Nigeria with different climatic conditions and water usage costs. The results show that in the hot (ambient temperatures >33 • C) and dry regions (relative humidity <65%) namely Sahel, Sudan, and Guinea savannah, the plant with wet cooling generated more net power outputs with lower life-cycle costs, operating and maintenance costs than with dry cooling. Thus, for these three regions, the wet cooling system is the best option. But for the Tropical Rainforest and Coastal zones with low ambient temperatures (≤31 • C) and high relative humidity values (≥76%), the performance and cost implications of the plant with dry cooling was more favourable due to lower system sizes and costs requirements. Parametric investigations revealed that high ambient temperature increased the size and costs requirements of air-cooled systems while relative humidity significantly influenced the total power consumption of water-cooled systems.
... He also pointed out that the performance degradation of the fan due to the distortion of the airflow at the upstream fan inlet is the main reason for the decline in the ACC's performance, and the accumulation of hot plume also led to a reduction in the ACC's performance. Alan O'Donovan et al. [12] experimentally studied that the increase in fan speed causes the temperature and pressure of the ACC to decrease, and vice-versa. Wang et al. [8] proposed setting side panels below or above the platform to prevent plume recirculation because of the flow separation at the inlet of the fan. ...
... Energies 2019,12, 4560 ...
... Energies 2019, 12, 4560 ...
In air-cooled power units, an air-cooled condenser (ACC) is usually accompanied by mechanical draft wet-cooling towers (MCTs) so as to meet the severe cooling requirements of air-cooling auxiliary apparatuses, such as water ring vacuum pumps. When running, both the ACC and MCTs affected each other through their aerodynamic fields. To make the effect of MCTs on the cooling performance of the ACC more prominent, a three-dimensional (3D) numerical model was established for one 2 × 660 MW air-cooling power plant, with full consideration the ACC, MCTs and adjacent main workshops, which was validated by design data and published test results. By numerical simulation, we obtained the effect of hot air recirculation (HAR) on the cooling performance of the ACC under different working conditions and the effect of MCTs on the cooling performance of the ACC. The results showed that as the ambient wind speed increases, the hot recirculation rate (HRR) of the ACC increased and changed significantly with the change of wind directions. An increase in ambient temperature can cause a significant rise in back pressure of the ACC. The exhaust of the MCTs partially entered the ACC under the influence of ambient wind, and the HRR in the affected cooling units was higher than that of the nearby unaffected cooling units. When the MCTs were turned off, the overall HRR of the ACC decreased. The presence of MCTs had a local influence on the cooling performance of only two cooling units, and then slightly impacted the overall cooling performance of the ACC, which provides a good insight into the arrangement optimization of the ACC and the MCTs.
... Air cooled condensers are the option to replace wet type cooling tower and get rid of the water consumption costs. An analytical model of modular type air cooled condenser is developed from experimental analysis of previous works in Ref. [39]. Fig C.4 in Appendix was adapted from their work which illustrates the modular air cooled condenser used for steam condensation. ...
... Fig C.4 in Appendix was adapted from their work which illustrates the modular air cooled condenser used for steam condensation. The authors in Ref. [39] suggested an analytical model and test its validity in experiments. They suggested that for the mentioned air cooled condenser the condensing temperature is given by Eq. (21) T cond ¼ T out;a À T db;a 1 À exp ÀNTU þ T db;ai ...
... The right-hand side of Eq. (23) is the summation of overall thermal resistance which is presented in Fig. 7 of [39] as a function of fan speed. The fan laws in connection with Figs. 2 and 7 of [39] were used to obtain raw data in terms of air mass flow rate. ...
This article compares the part-load operation of air cooled and cooling tower based low-medium temperature geothermal Organic Rankine Cycle (ORC) systems installed at different geographical locations. Working fluid R245fa was compared with a newer competitor R1233zde for thermo-economic performance, environment-friendly and efficient system integration. Monthly averaged, weather data is used to simulate ambient conditions of Ulsan, London, Vegas and Kuala Lumpur. Mathematical models for condenser part load operation were formulated for both air cooled and mechanical draft wet cooling tower based systems. Numerical study and experimental validation was performed for the condenser when wet cooling tower based system was investigated. The ORC system design was optimized for maximum power output to grid and operational control optimization was performed on the heat sink to achieve maximum power output at different ambient or off-design conditions. Economic analysis was performed by comparing the capital investment/kW and levelized cost of electricity (LCOE) over the lifetime of the system. Based on the economic analysis, the results reveal that R1233zde has potential to replace R245fa working fluid when the source temperature is higher (around 145 °C). Cooling tower based system are preferable for hot dry regions while air-cooled systems can be implemented with R1233zde for Ulsan and London.
... This model was later modified for use with wavyfinned tubes [7]. The asymptotic-composite modelling approach has been shown to be relatively accurate in predicting the behavior of straight-finned rectangular tube heat exchangers [8,9]. The tube considered in [8,9] had roughly similar dimensions to those of the current study and was investigated for a mechanical draft ACC application. ...
... The asymptotic-composite modelling approach has been shown to be relatively accurate in predicting the behavior of straight-finned rectangular tube heat exchangers [8,9]. The tube considered in [8,9] had roughly similar dimensions to those of the current study and was investigated for a mechanical draft ACC application. The methodology is yet to be applied to a wavy-finned flattube specifically. ...
Wavy-finned, flat-tube heat exchangers are used in industrial applications for their relatively low frictional pressure drops and high heat transfer coefficients. Originally developed for mechanical draft systems, these heat exchangers are now finding application in natural draft (buoyancy driven) systems (e.g. in natural draft air-cooled condensers (NDACCs)). In the context of these natural draft systems, careful consideration of finned tube configuration (notably fin configuration) is warranted due to the juxtaposition of pressure drop (resistance) and heat transfer coefficient (which contributes to motive potential) in these tubes and the sensitivity of the overall system performance to these parameters. This study presents and validates a three-dimensional computational fluid dynamics model of a wavy-finned flat ACC tube employing the transitional 𝑘 − 𝜔 SST turbulence model in Ansys Fluent 2023 R1. The numerical results are validated against experimental data and shown to correlate well in terms of both thermal and hydraulic performance prediction over the full flow range considered (Reynolds numbers of 400 to 2000 , encompassing laminar and transitional flow). Two semi-empirical finned tube models are considered and shown to be inaccurate for the specific tube considered. A full-factorial analysis of fin spacing, fin thickness, wavy amplitude and wavy wavelength identifies fin spacing and wavy amplitude as the most significant factors, and wavy wavelength is highlighted as an interesting parameter.
... The steam condenser is a critical component in a power plant with a condensing steam turbine [21,22]. Numerous studies in the literature have investigated the impact of various parameters, such as cooling water temperature at the condenser inlet, cooling water mass flow rate, and steam pressure, on the performance of steam condensers and overall power plant efficiency [23][24][25][26]. ...
... The steam condenser is a critical component in a power plant with a condensin steam turbine [21,22]. Numerous studies in the literature have investigated the impact o various parameters, such as cooling water temperature at the condenser inlet, cooling wa ter mass flow rate, and steam pressure, on the performance of steam condensers and over all power plant efficiency [23][24][25][26]. ...
The prolonged operation of thermal power plants inevitably leads to component aging and a gradual decline in performance. This deterioration increases the gross heat rate and reduces electrical output, resulting in higher fuel consumption and lower electricity production. Consequently, these issues can cause significant financial losses and threaten the plant’s competitiveness. This paper presents a comprehensive methodology for improving the performance of existing plants. The methodology consists of two crucial elements: steam turbine testing and numerical simulation of the process. The tests should be comprehensive to ensure accurate measurements and reliable conclusions. The developed method for process simulation enables the calculation of overall performance, like specific heat rate and thermal efficiency, as well as the performance of individual components under various operational conditions. Comparing numerical results with experimental data can effectively identify operational problems. Based on these findings, targeted overhauls and other corrective measures can substantially improve the plant’s thermal efficiency and financial performance. The system was demonstrated through a case study of a 120 MW coal-fired steam turbine. The test revealed that it consumes more than 10% additional heat compared to its original design specifications. The analysis identified operational issues and recommended improvement measures, focusing exclusively on the steam turbine set while excluding the boiler.
... Condensation pressure is an important system-level parameter. Decreasing condensation pressure improves power-plant performance by increasing the Carnot efficiency, as shown by O'Donovan and Grimes [21]. Only a few previous experimental parametric studies of ACC performance have been performed and only one in a flattened-tube geometry. ...
... Only a few previous experimental parametric studies of ACC performance have been performed and only one in a flattened-tube geometry. Of the previous studies, O'Donovan and Grimes [21] showed through thermodynamic modeling of a power plant that decreasing condensation pressure decreases the capacity of an ACC, due to decreased steam-ambient temperature difference. In a combined experimental and numerical study of air-steam condensation inside an ACC, Sukhanov et al. [22], found that condensation HTC increased as inlet steam-air velocity increased. ...
The effect of airflow profile and condensation pressure on the performance of air-cooled condensers is investigated experimentally. Two large, flattened-tube air-cooled steam condensers are studied. The tube lengths are 10.7 and 5.7 m, with inner dimensions of 216 × 16 mm and aluminum fins on each side of the elongated-slot cross sections. Capacity and pressure drop are measured and discussed here. All tests are performed with a horizontal tube and co-current vapor and condensate flow. Four different profiles of cross-flowing air are tested: uniform air flowing upwards, uniform air flowing downwards, and two profiles of non-uniform air flowing upwards. For the 10.7 m tube, reversing airflow direction from upwards to downwards is found to significantly increase condenser capacity. Also for the 10.7 m tube, a favorable non-uniform air-velocity profile is shown to increase capacity in comparison to a uniform air-velocity profile. Both of these performance increases are shown to be the result of matching regions of maximum heat transfer coefficient on the air and steam sides. For the 5.7 m tube, a non-uniform airflow profile is shown to have no effect on capacity. Reducing condensation pressure is shown to decrease condenser capacity for both condenser tubes.
... Air-cooled steam condensers (ACCs) are used in thermal power plants as an alternative cooling method to once-through or recirculating wet cooling. Although the air side is the larger resistance to heat transfer, the steam side has been found to account for up to onethird of the total thermal resistance [1]. Therefore, increasing the thermal performance on the steam side can reduce condenser first and installation costs by reducing the required heat transfer area. ...
... O'Donovan and Grimes [1] also investigated steam-side heat transfer resistance experimentally, looking at a flattened-tube ACC array in a power plant with tubes of 2 m length. They experimentally determined overall condenser thermal resistance, and inferred steam-side thermal resistance by subtracting the theoretical air-side resistance from this overall resistance. ...
Experimental results for capacity and heat transfer coefficient during steam condensation in a power-plant air-cooled condenser are presented. The condenser test section is a flattened steel tube with brazed aluminum fins. The tube is 5.7 m long with inner dimensions of 216 mm × 16 mm. The cooling air is in crossflow to the steam, with velocity at the fin inlet of 2.4–3.0 m s⁻¹. Condensation pressures range from 70–105 kPa, with the tube inclined from 0–49° downwards. Adiabatic visualization sections at the tube inlet and outlet provide identification of annular flow at the inlet and stratified flow at the outlet. Steam-side heat transfer coefficient is found to depend on wall-steam temperature difference, with minimal dependence on quality or vapor Reynolds number. As a result, steam-side heat transfer coefficient does not decrease significantly along the condenser length, as is common for smaller condenser tubes with higher mass flux. There is a slight decrease in steam-side heat transfer coefficient near the condenser outlet due to a build-up of condensate at the tube bottom. Overall condenser heat transfer coefficient is found to decrease near the condenser outlet due to an increase in the thickness of the stratified condensate layer.
... Later, O'Donovan and Grimes [17] carried out a series of experimental measurements taken on a full-scale prototype, which were used for the assessment and prediction of steam-side characteristics of the ACC. Experimental data and empirical correlations were employed for the evaluation of a 50 MW power plant. ...
... Two approaches devised for considering this issue were identified in the literature review and implemented in the semi-empirical model of the ACC. The technique adapted from Michejev [33] uses the correction factor ε NCG as a function of the concentration x NCG of noncondensing gases ε NCG ¼ 0:317 expðÀ4:613 x NCG Þ þ 0:532 expðÀ0:640 x NCG Þ þ 0:152 (17) which was determined as the approximation of data presented in Ref. [33]. Similarly as in case of the influence of the steam velocity, the steam-side HTC taking into account the presence of noncondensing gases is determined as HTC à steam ¼ ε NCG HTC steam : The method adapted from Caruso et al. [34] utilises the correction factor determined as ...
Many economic and environmental restrictions have resulted in the growth of dry cooling technology.
The air-cooled condenser (ACC), which can be used in power plants and other facilities, represents a way
toward the minimisation of the water footprint. In the paper, a semi-empirical computational tool
devised for the design and thermal assessment of the ACC is introduced. In comparison to commonly
used CFD-based models, the presented tool is computationally effective and inexpensive. The model is
based on a control-volume computational grid, which is coupled with three sub-models for the solution
of steam-side, air-side, and fan-related phenomena. A number of empirical correlations collected in the
literature review were incorporated in the model. Besides the underlying functionality, which includes
the determination of the steam condensation capacity, the model allows for the consideration of
advanced physical phenomena such as the condensate glut control and the influence of air in the steam
to the condensation process. The comparison of the model with datasheets from manufacturers of ACCs
as well as with experimentally gained data from a municipal solid waste incineration plant demonstrates
that the semi-empirical model is a fast and accurate tool applicable for the design and thermal assessment
of the ACC.
... Xuelei Zhang and Tingting Wu [2] installed a diffusion orifice plate structure in the lower part of the air-cooled condenser platform to eliminate the adverse effects of ambient wind-to-air condenser heat flow. Alan O'Donovan, Ronan Grimes [3] proposed a new modular air-cooled condenser (MACC). Weifeng He [4] et al. studied the mechanism of the temperature increase of the air inlet of a forced air blower in an air-cooled steam condenser. ...
... According to the gas phase data of the region, the range of ambient temperature change in this area is -25 °C-30 °C, and the relationship between the condensation capacity of the air -cooled condenser and the ambient temperature at different fan rotation speeds is obtained as shown in Figure 2: It can be seen from the figure that the condensation capacity of the air-cooled condenser decreases with the increase of the ambient temperature; meanwhile, it can be seen that as the ambient temperature increases, the effect of the fan speed is weaker. In addition, at different fan rotation speeds, the ratio of the condensation capacity of the air-cooled condenser at 30 °C to the condensation 3.75, which indicates that the ambient temperature is an important environmental factor affecting the condensation capacity of the air-cooled condenser. ...
The working environment of the air-cooled condenser is very complicated. By analyzing the heat transfer process of the air-cooled condenser, it is found that the temperature of the environment, the lateral wind speed in the environment and the rotational speed of the axial fan all have an influence on the condensation capacity of the air-cooled condenser. Through research, it is found that the condensation capacity of the space-time condenser at -25 ° C is about 3.75 times that at 30 ° C; compared with no lateral wind speed, when the wind speed increases from 4m/s to 12m/s, the decline of the condensation capacity of the air condenser changes from 1.2% to 12.6%; when the axial fan is at 1.1 times rated speed, its condensation capacity is 1.6 times that of 0.5 times. It can be seen that the rotational speed of the axial flow fan and the ambient temperature are the main influencing factors, and the rotational speed of the axial flow fan is an active adjustment factor. Furthermore, the control scheme of the axial fan speed as a function of ambient temperature can be obtained through analysis.
... As mentioned above the main purpose of this research is to increase the cycle efficiency by decreasing the condenser temperature. A. O'Donovan and R. Grimes [16], derived a formula for the steam condenser temperature in ACC as: ...
... Plate-fin heat sink geometry with rectangular channels[16]. ...
Restriction on water consumption is becoming an increasing problem for the power generation industry. As an alternative both to once-through cooling and to surface condenser/wet-cooling tower combination, utility companies and equipment manufacturers are considering, and even implementing, air-cooled condenser (ACC). However, the industry is quite reluctant to switch over to ACC for three important reasons: (a) lower power output, (b) higher capital cost, and (c) larger physical foot-print, all because of the same reason — it is not as efficient to transfer heat from condensing steam to air as it is to transfer to water. In other words, overall thermal resistance from condensing steam to the ambient air is significantly higher than to cooling water.
To get a clear and full understanding of the heat transfer process occur in air-cooling condenser, Detailed mathematical equations were derived to model the heat transfer process through the fined-tubes of the ACC. The total thermal resistance model was analyzed and investigated to identify the design components with highest affect in the process.
The paper proposes a viable cooling system based on novel heat pipe technology which addresses these problems. This technology employs boiling as the means to store and transfer heat energy. A detailed mathematical set of equations was derived to model the heat pipe thermal resistance. A comparison of the heat transfer performances of the ACC technology and the proposed method is presented.
The proposed cooling system suggests a solution for each of the three components of the thermal resistance, the super-hydrophobic coating of the steam ducts internal surfaces increased the condensing heat transfer rate by an order of magnitude, the proposed design of the heat pipes improved the external heat transfer, and the installation mechanism improves the fin efficiency by eliminating the contact resistance between steam duct and the heat pipe.
... Also, increase the momentum that will transfer from steam to condensate film. While at cooling water temperature of 26.6℃, the local steam heat transfer coefficient has weakened even though the increase in the rate of heat rejected which as shown by the authors [37], the rate of increase in Nusselt number diminishes at higher Reynolds numbers although the increasing of air-side heat transfer coefficient where used as a coolant media. ...
The steam condensation process has been experimentally investigated in an air-cooled condenser (ACC). The ACC has been designed and built using a flattened cross-section horizontal tube. The flattened tube has an internal dimension of 102 mm x 12 mm with 4030 mm length. A range of vacuum operating conditions are applied to operate the ACC. In the experiments, parameters such as vacuum pressure, saturated temperature, wall tube temperature, rate of heat transfer, and local average steam heat transfer coefficient have been considered along the flow direction with the variation of cooling water temperature. The experimental results revealed that the steam saturated temperature and the related pressure decrease with the reduction of the cooling water temperature, and the temperatures of the upper and lower parts of the horizontal flattened tube. The results also showed that the local steam condensation heat transfer coefficient decreases along with the direction of the flow, but it there is incrementing with the decreasing of saturated steam temperature at a certain range of cooling water temperature.
... The sum of TTD, approach, and cooling range is termed as initial temperature difference (ITD) (Mittelman & Epstein, 2010). To obtain better performance from a cooling tower, the range should be high, and the value of the approach, ITD, and TTD should be low (Baker et al., 2014;O'Donovan & Grimes, 2014;Poullikkas et al., 2013a, b, c;Wagner & Kutscher, 2010b). The design values of ITD govern the size (or surface area) of cooling system and the same can be optimized by economic and performance analysis between the primary energy source, cost of cooling technology, parasitic load and net Content courtesy of Springer Nature, terms of use apply. ...
Selection of condenser cooling technology can affect the financial as well as technical viability of concentrating solar power (CSP) plants. Detailed comparative assessment of three cooling technologies, i.e., wet, dry, and hybrid, is therefore desirable so as to facilitate selection of optimum cooling technology for the plant. Despite the high efficiency of wet cooling technology, considering the fact that the potential plant locations are generally in arid regions suffering from water scarcity, it is imperative to explore and consider other water conserving condenser cooling options. A review and comparison of technical, economic, and environmental aspects of the three condenser cooling technologies for CSP plants have been presented. Adoption of dry or hybrid technology as against wet cooling technology may lead to reduced thermal performance and increased parasitic power requirement resulting in the high cost of electricity generation. However, the same also results in reduced cooling water requirement up to 92% and thus increase the potential of solar thermal power generation considerably as sites in arid areas can also be utilized.
... Air cooling (throughout this paper we use the term 'air' for 'dry air') of thermal power plants has been used in a few isolated instances [4][5][6][7]. With air cooling, the exhaust vapor-liquid steam from the turbine generator is circulated through a series of finned tubes in a condenser and is cooled down by a stream of ambient air blown by fans over the tubes. ...
To our knowledge, the potential use of CO2 as a heat-transmitting fluid for cooling applications in power plants has not been explored very extensively. In this paper, we conduct a theoretical analysis to explore the use of CO2 as the heat transmission fluid. We evaluate and compare the thermophysical properties of both dry air and CO2 and perform a simple analysis on a steam-condensing device where steam flows through one of the flow paths and the cooling fluid (CO2 or air) is expanded from a high-pressure container and flows through the other. Sample calculations are carried out for a saturated-vapor steam at 0.008 MPa and 41.5 °C with the mass flow rate of 0.01 kg/s. The pressure of the storage container ranges from 1 to 5 MPa, and its temperature is kept at 35 °C. The pressure of the cooling fluid (CO2 or dry air) is set at 0.1 MPa. With air as the heat-removing fluid, the steam exits the condensing device as a vapor-liquid steam of 53% to 10% vapor for the container pressure of 1 to 5 MPa. With CO2 as the heat-removing fluid, the steam exits the device still containing 44% and 7% vapor for the container pressure of 1 MPa and 2 MPa, respectively. For the container pressure of 3 MPa and higher, the steam exits the device as a single-phase saturated liquid. Thus, due to its excellent Joule–Thomson cooling effect and heat capacity, CO2 is a better fluid for power plant cooling applications. The condensing surface area is also estimated, and the results show that when CO2 is used, the condensing surface is 50% to 60% less than that when dry air is used. This leads to significant reductions in the condenser size and the capital costs. A rough estimate of the amount of CO2 that can be stored and utilized is also carried out for a steam power plant which operates with steam with a temperature of 540 °C (813 K) and a pressure of 10 MPa at the turbine inlet and saturated-vapor steam at 0.008 MPa at the turbine outlet. The results indicate that if CO2 is used as a cooling fluid, CO2 emitted from a 1000 MW power plant during a period of 250 days could be stored and utilized.
... For comparison, O'Donovan and Grimes [53] used an analytical method to determine air-side HTC in a flattened-tube condenser. Their experimentally-validated result exceeds the mean HTC determined by Eq. (12) by 8% for the conditions tested. ...
Experimental results for counter-flow steam condensation in a 5.7 m-long air-cooled condenser tube with a flattened-tube cross section are presented. The tube is inclined at upward inclination angles from 0.5° to 40°, with both the vapor inlet and liquid outlet at the lower end of the tube. The effect of inclination angle on flow regimes, void fraction, capacity and heat transfer coefficient is presented. In addition, a water-cooled test section provides local steam-side heat transfer coefficient along the tube circumference at increased accuracy to that determined in the air-cooled test section. The range of condensation pressures tested is 88–120 kPa and all tests have a mass flux of less than 4.2 kg m⁻² s⁻¹. Stratified flow is found for nearly all conditions and locations in the condenser. Flooding of this stratified condensate layer is found for tube inclination angles of 5° and lower. This flooding is found to reduce the condenser capacity. The results are compared to those for co-current flow in the same condenser tube. Capacity is found to be unaffected by the flow configuration (counter-flow vs. co-current) when flooding does not occur. Steam-side heat transfer coefficient is also found to be unaffected by flow configuration for all conditions tested.
... Failing to maintain low turbine outlet temperatures results in significant efficiency penalties. Indeed, data presented by O'Donovan and Grimes [2] illustrated that a 1°C increase in turbine outlet temperature caused a 0.42% reduction in turbine gross power output. As the condenser is responsible for achieving and maintaining the desired turbine outlet steam temperature, condenser design and operational optimisation is a critical aspect of Rankine cycle efficiency. ...
This paper presents the essentials of low temperature thermal storage (LTTS), a novel technique whereby thermal energy storage is employed to achieve sub-ambient condensation in air-cooled Rankine cycle power plants. It summarises work which was undertaken to explore the potential and the range of application of LTTS. The technology is most effective at geographical locations with large average daily temperature ranges, and high summertime temperatures. Hourly normal temperature data was sourced for five potential deployment sites, which provided a representative sample of different climate types. A steam turbine, a condenser, an air-cooled heat exchanger, and a chilled water thermal energy storage tank formed the LTTS configuration – a techno-economic model of which was developed to simulate system behaviour. The size of the air-cooled heat exchanger, the fan speed of the air-cooled heat exchanger, and the hours of charge, discharge, and bypass of the thermal energy storage tank were all modelled as variables to determine the effects of component sizes and operating patterns. LTTS performance was benchmarked by comparison with a direct air-cooled condenser model. Results presented in this paper include daily plant output, annual power output, and payback period. This study shows that LTTS can deliver all the advantages of dry-cooling, without suffering the usual performance degradations. The inherent flexibility of LTTS allows for configurations to be customised to exploit the prevailing site climate, and capitalise on the local power demand pattern. There are also clear indications that, in suitable climatic settings, LTTS outperforms traditional air-cooled thermal power plants by offering up to 10% additional generating capacity. Coupled to this are payback periods as short as 2.5 years, ensuring LTTS can be considered a viable alternative to current air-cooling strategies.
... In specialized literature (O'Donovan & Grimes, 2014;H uang et al., 2016;Peduzzi et al., 2016;Kiran & Muthukumar, 2017),a consid erabl e group of ex pressions f or th e d etermination of h igh er cal oric pow er ( Q SC ) of a d ry sol id f uel is reported . A summary of th e most w id espread is given in Tabl e 4 accord - ing to Peduzzi et al. ( 2016). ...
This paper presents the results of the continuity in a research process carried out at the Center for Energy and Environmental Technologies Studies, belonging to Marta Abreu Central University of Las Villas, related to obtaining models for the determination of caloric powers and chemical exergy contained in any solid combustible element of biomass origin. The main formulations known in the literature are presented, as well as the results obtained by the authors to represent the lower caloric power and the chemical exergy in terms of elemental composition (C, H, O, N, and S). The formulations obtained correlate with the samples considered between 5% and 15% for the higher caloric power, and between 1,3% and 2,4% for chemical exergy. Based on these correlations, this study provides the relationship between higher caloric power and chemical exergy as a function of the elemental composition of C, H, O, N, and S in the fuel masses that will be used in biomass thermoelectric power stations (TPS) in process of construction in the country
... By CFD simulation and Experimental validation, Lee et al. [17,18] proposed VV-shaped finned-tube condenser coils with an upper fan, which is considered to improve airflow distribution and enhance heat transfer performance. A new modular air-cooled condenser design and experimental set-up is presented by O′Donovan et al. [19], which can improve efficiency and reduce costs. A novel vertical arrangement of air-cooled condensers is proposed to weaken the adverse wind effects and utilize the wind power to improve the cooling capacity of air-cooled condensers by Chen et al. [20]. ...
Uneven distribution of internal temperature and air flow field are considered to be the essential defects of the Λ-frame air-cooled condenser (ΛACC) in a power plant. Lateral air supplement to a noble, truncated cone-shaped air-cooled condenser (TCACC) is investigated by mean of numerical simulation to solve these problems fundamentally and improve the performance of the air-cooled condenser (ACC) obviously. A Circular ring, installing at the bottom of the heat transfer surface, the structure of which is optimized. According to compare a series of ACCs in different fan inlet air conditions, the TCACC with a lateral air supply (TCACCL) is obtained for heat transfer and safety. The numerical results indicate that the lateral air supplement is an effective way to improve the thermo-flow performance of TCACC.
... Following the work of Donovan and Grimes [34] the air cooled condenser analysis is performed. The analysis is based upon the assumption that only isothermal heat rejection occurs during condensation, the amount of heat rejected to condense steam to liquid water is totally absorbed by the cooling air, with sensible heat rejection (sub cooling) neglected. ...
This paper presents the thermodynamic, economic and environmental impact assessment of an existing combined cycle power plant to be retrofitted with a waste heat driven aqua lithium bromide absorption refrigerator for cooling the inlet air streams to the compressor and air cooled steam condenser. The power plant is located in the hot and humid tropical region of Nigeria, latitude 4°45′N and longitude 7°00′E. Using the operating data of the plant, the results of the analysis showed that by cooling the inlet air to the compressors to 15°C, the net power output of the gas turbine cycles increased by 48.3MW, and by cooling the inlet air streams to the air cooled steam condenser to 29°C, the net power output of the steam turbine cycle increased by 1.4MW. The overall thermal efficiency of the plant increased by 8.1% while the specific fuel consumption decreased by 7.0%. The stack flue gas exit temperature reduced from 126°C to 84°C in the absorption refrigerator, thus reducing the exhaust heat discharge rate to the atmosphere. The total capital cost, life cycle cost, annual sales revenue and net present value increased by 3.3%, 2.3%, 7.7% and 17%, respectively while the levelized cost of energy production in the plant and the break-even point of the investment reduced by 4.8% and 5.6%, respectively. Environmental impact analysis revealed that the emission rates of NOx and CO 2 emissions per MWh decreased by 65% and 7.3% respectively while the rate of CO emission increased with inlet air cooling by 12.1%. Thus inlet air cooling offers improved thermodynamic output, increased return on investment and greater environmental sustainability.
... Despite more or less symmetric floor planning in both horizontal directions, the stiffness and mass are usually unevenly distributed in the vertical direction due to the peculiar characteristics of structural components and industrial requirements. Past studies mainly focused on the ACC technology including experimental investigation, numerical simulation and optimization [4][5][6][7][8][9]. However, the supporting structure of the ACC system was addressed rarely. ...
This paper aims to provide an experimental support on seismic performance evaluation of the steel braced truss-RC (reinforced concrete) column hybrid structure, which could be applied as the air-cooled supporting structural system in large-capacity thermal power plants located in strong earthquake prone regions. A series of pseudo-dynamic tests (PDTs) and quasi-static tests (QSTs) were performed on a 1/8-scaled sub-structure. The dynamic characteristics, lateral deformation patterns, deterioration behavior, hysteretic behavior and failure mechanisms were investigated. Test results showed that the first vibration mode is torsion, which is caused by the small torsional stiffness of this kind of hybrid structure. The lateral deformation shape is shear mode, and the drift ratio of the structure above the corbel is significantly less than that of the column below the corbel. Earthquake energy is mainly dissipated by the RC pipe columns where cracks mainly occurred at the bottom of column and lower part of corbel. The failure mechanisms were identified indicating that the steel braces improved the global stiffness and modified the load transfer mechanism. This study affirms that the steel braced truss-RC column hybrid structure has the sufficient ductility and good energy dissipation capacity to satisfy the design requirements in high seismic regions.
... Recently, various novel constructions of air-cooled condensers are proposed, which have many advantages over the traditional air-cooled condensers. O'Donovan et al. [21][22][23] presented a novel modular air-cooled condenser mainly used in solar or thermoelectric power plants, which can be pre-assembled with small controlled axial flow fans. Butler and Grimes [24] studied the wind effect on the modular air-cooled condenser and proposed the optimal condenser configuration. ...
Ambient winds are generally unfavorable to the thermo-flow performances of air-cooled condensers in power plants. More emphases are placed to weaken the negative effects of ambient winds, but no layout alternative of air-cooled condensers is considered. In this work, a novel vertical arrangement of air-cooled condensers is proposed on the basis of a 2 × 600 MW direct dry cooling power plant, which can weaken the adverse wind effects and utilize the wind power to improve the cooling capacity of air-cooled condensers. By means of the CFD simulation and experimental validation, the flow and temperature fields of cooling air for the vertically arranged air-cooled condensers at ambient winds are obtained. The mass flow rate, inlet air temperature and turbine back pressure are computed and compared with the traditional air-cooled condensers. The results show that the flow rate of the novel air-cooled condensers increases conspicuously compared with the current ones both in the absence and presence of winds. In the wind directions of 60° and 90°, the off-axis flow distortions of axial flow fans are greatly weakened and the average inlet air temperature of the novel air-cooled condensers is reduced and almost equals the ambient temperature. The thermo-flow performances of the air-cooled condensers are improved, thus the turbine back pressure is reduced by the novel layout of air-cooled condensers.
... In order to alleviate deficiencies associated with current ACCs, a modular aircooled condenser (MACC) is proposed. It has been shown through previous studies by O'Donovan and Grimes [10], Moore et al. [11] and Butler and Grimes [12] that this design has the potential to maximise plant output and minimise parasitic losses. However, a factor which could inhibit the performance of the MACC, or any ACC for that matter, is the pressure losses associated with the two-phase condensing flow of steam through the tube bundle. ...
Direct air-cooling systems use air instead of water as a cooling medium, so they are easily affected by meteorological and hydrological conditions. In this paper, considering the complex geographic conditions around the direct air-cooling units, Gambit is used to model the direct air-cooling system, including the complex mountainous terrain, and the performance simulation of the direct air-cooling system and the complex mountainous terrain near the power plant is realized by combining the CFD method with the MATLAB mathematical model of the power plant. Through the simulation, the operation of the ACC system under various meteorological conditions is obtained, and the influence of environmental factors and complex geographic conditions on the performance of the ACC system is investigated and further analyzed for the special case of the back-furnace wind. On this basis, a clustering analysis algorithm was used to obtain the results of turbine zoning in different wind directions and to analyze the physical field shifts of the units caused by geographic factors.
Achieving optimum energy conversion in thermodynamic systems, such as in the thermal power plants (TPPs), is a complex task due to the involvement of several factors. One of the effective ways of determining the quantity & quality of energy systems is via energy and exergy analysis. This study is a comparative evaluation of the energy & exergy analyses of coal and gas-fired TPPs. Details of different studies on TPPs over the years were critically reviewed, followed by independent thermodynamics analysis of each component of the TPPs system. Improvements in the performance of power plants were also highlighted. From the outcome of the comparative analysis, combustion chambers were identified as the main contributors to exergy destruction owing to their associated high irreversibility. The results show that the exergy efficiency of the entire system is about 20%. The main exergy loss were occurred in the boiler and the steam turbine in the system. For further improvements, this review highlighted some of the areas for further research and made recommendations for improvement in some aspects of the existing TPPs.
Cold-end systems are heat sinks of thermal power cycles, which have an essential effect on the overall performance of thermal power plants. To enhance the efficiency of thermal power plants, multi-pressure condensers have been applied in some large-capacity thermal power plants. However, little attention has been paid to the optimization of the cold-end system with multi-pressure condensers which have multiple parameters to be identified. Therefore, the design optimization methods of cold-end systems with single- and multi-pressure condensers are developed based on the entropy generation rate, and the genetic algorithm (GA) is used to optimize multiple parameters. Multiple parameters, including heat transfer area of multi-pressure condensers, steam distribution in condensers, and cooling water mass flow rate, are optimized while considering detailed entropy generation rate of the cold-end systems. The results show that the entropy generation rate of the multi-pressure cold-end system is less than that of the single-pressure cold-end system when the total condenser area is constant. Moreover, the economic performance can be improved with the adoption of the multi-pressure cold-end system. When compared with the single-pressure cold-end system, the excess revenues gained by using dual- and quadruple-pressure cold-end systems are 575 and 580 k$/a, respectively.
A current trend for electrical power generation in areas with water difficult access is the
use of air-cooled steam condensers (ACC). Currently in the literature available there is
no single method that brings together all factors that are considered in the evaluation of
a power plant operating with dry condensation system. In present work a unique method
of analysis is developed that considers the action of the environmental variables that act
on the ACC installation, allowing therefore to determine its final effect on the power
installation. The new proposal follows the logical order of the Kröger method because
this is the most widely accepted and disseminated among researchers and specialists
working in this field. In a total of 127 tests carried out, there is an average uncertainty in
the results obtained with this method of 8.2%, which they are considered sufficiently
precise for their use in thermal engineering.
______________________________________________________________________ RESUMEN El proyecto inversionista de 25 centrales termoeléctricas (CTE) de biomasa en Cuba con potencias de 20 y 50 MW, así como la carencia probada de agua para sus sistemas de enfriamiento, apuntan al posible empleo de sistemas de condensadores secos (ACC) en dichas plantas, sin embargo el encarecimiento del proyecto inicial y la reducción de potencia útil asociada su empleo es una limitante a considerar. Para definir la factibilidad del empleo de ACC en estos proyectos se realiza un estudio de caso en el cual son considerados varios criterios de selección para alternativas de inversión, siendo evaluados adicionalmente otros tres tipos de tecnologías de condensación con el objetivo de establecer comparación de costos de inversión y operación, así como de las utilidades generadas. En todos los casos los análisis fueron efectuados para un horizonte de 20 años. Los resultados obtenidos confirman la factibilidad del empleo de sistemas ACC, con un período de recuperación compuesto de la inversión de 7,6 a los 8,4 años, la Tasa de Interés de Retorno (TIR) computa valores entre el 18,2 a 23,8 por ciento, el Valor Actual Neto (VAN) con una tasa de actualización del 15% alcanza valores entre los 1 126,9 a 3 024,0 MUSD, el costo del ciclo de vida se ubica entre los 10 682,4 a 24 406,1 MUSD, mientras que el costo nivelado de la energía fluctúa entre los 0,062 a 0,071 USD/kWh, con una relación costo beneficio entre 0,1 a 0,13. Palabras clave: costo ciclo de vida; costo nivelado; industria azucarera; planta de potencia.
______________________________________________________________________ RESUMEN Para un condensador de vapor refrigerado por aire (ACC), el viento ambiental puede causar una gran reducción del caudal en los ventiladores axiales principalmente cerca del lado de barlovento de la plataforma enfriada por aire debido a los efectos de flujo cruzado, lo que resulta en una reducción de transferencia de calor. Esto conduce a un aumento de la contrapresión de la turbina. En este documento se propone un nuevo método para evaluar el efecto del viento en la presión de salida de la turbina, así como el efecto de la combinación de la temperatura ambiental con la acción directa del viento. Finalmente los resultados obtenidos son dados en formas de gráficas y son propuestas un grupo de ecuaciones que permiten obtener la presión de salida de turbina, siendo conocidas las temperaturas ambientales y la velocidad del viento. Estas expresiones correlacionan en todos los casos con un error medio igual al 11,27 % en el 89,12 % de los datos experimentales disponibles, por lo que se consideran suficientemente precisas para su empleo en la ingeniería térmica. Palabras clave: Presión de salida; temperatura ambiental; transferencia de calor; velocidad del viento.
New generalized correlations for predicting the average Fanning friction factor f and average Nusselt number Nu for laminar flow in plain plate-fin compact cores of rectangular cross section are presented. These are based on extended experimental data, as well as three-dimensional computational simulations, obtained for a broad range of fin density and geometrical attributes. The results indicate that while the fully developed forced convection scales only with the inter-fin channel cross-sectional ratio alpha (fin spacing by fin height), the entrance region hydrodynamic and thermal performance is additionally a function of the fin-core length L, flow Reynolds number Re, and fluid Prandtl number Pr. The developing flow and convection is further shown to scale as: fRe ~ L, dh, Re, and Nu ~ L, dh, Re, Pr, alpha, where f, Re, and Nu are all based on the hydraulic diameter dh of the inter-fin flow channel. Generalized correlations for both fRe and Nu are developed by the corresponding scaling of the forced convection behavior and asymptotic matching of the entrance or developing flow (short fin-core flow length) and the fully developed flow (large fin-core flow length) region performance. Finally, the predictions from these correlations are found to be within ±15% of all available experimental data for air, water, and glycol (0.71 < Pr < 10), and fin cores with 0 < alpha < 1.
The investment project of 25 thermoelectric plants (CTE) of biomass in Cuba with powers of 20 and 50 MW, as well as the proven lack of water for their cooling systems, point to the possible use of dry capacitor systems (ACC) in these plants. However, the increase in the initial project cost and the reduction in useful power associated with its use is a limitation to consider. To define the feasibility of ACC use in these projects, a case study is carried out in which several selection criteria for investment alternatives are considered. Also three other types of condensation technologies are evaluated in order to establish the investment and operation cost comparison, as well as the profits generated. In all cases, these analyzes were carried out for a 20-year horizon. The results obtained confirm the feasibility of using ACC systems, with a composed investment recovery period from 7.6 to 8.4 years, the IRR computes values between 18.2 to 23.8 percent. The NPV with an update rate of 15% reaches values between 10682.4 and 3 024 MUSD, Life cycle cost is between 10 682.4 and 24 406.1 MUSD. Level cost of energy fluctuates between 0.062 to 0.071 USD / kWh, with a cost-benefit ratio between 0.1 to 0.13.
Offset-strip plate-fin compact heat exchangers are widely used in applications such as automobile radiators, electronic cooling devices, and HVAC heat exchangers. Higher heat transfer coefficient, compared to plain plate-fin, is obtained from the periodic disruption of the thermal boundary layer and the downstream fluid mixing. Air-flows (Pr = 0.71) in offset-strip plate-fin channels with the boundary surfaces subject to uniform temperature are investigated experimentally and computationally, and the associated Fanning friction factor f and Colburn factor j are obtained. The results characterize the rather distinct flow behavior in laminar and turbulent regions. The effects of offset length to hydraulic diameter ratio (0.3 < L/Dh < 3) are examined parametrically and are found to be the primary geometry variable influencing the performance. The enhancement in heat transfer rates under constant pressure drop condition is seen to be 2.5 – 3 times that for plain plate-fins with the smallest offset length ratio.
RESUMEN
En la actualidad para la generación de potencia eléctrica en las zonas con difícil acceso al agua, el empleo de condensadores de vapor refrigerado por aire (ACC) es una de las opciones más empleadas. Sobre el tema en la literatura disponible y conocida no existe un método único que aglutine la totalidad de factores que son requeridos en el estudio del proceso de transferencia de calor en un ACC. En el presente trabajo se desarrolla un método único de análisis que considera la acción de las variables ambientales que actúan sobre la instalación ACC, permitiendo por lo tanto determinar su efecto final sobre la instalación de potencia. La nueva propuesta sigue el orden lógico del método de Kröger, por ser este el de mayor aceptación y difusión entre los investigadores y especialistas que se desenvuelven en esta esfera. En un total de 149 pruebas efectuadas se encuentra una incertidumbre media en los resultados obtenidos con el método del orden del 8,7%, por lo que se consideran suficientemente precisas para su empleo en la ingeniería térmica. Palabras Clave: Eficiencia, planta de potencia, industria azucarera, transferencia de calor. New proposal for the determination of the heat transfer coefficients in air cooled condenser coupled to bioelectric power plant.. Abstract Currently, for the generation of electric power in areas with difficult access to water, the use of air-cooled condensers (ACC) is one of the most used options. On the subject in the literature available and known there is no single method that brings together all the factors that are required in the study of the process of heat transfer in an ACC. In the present work, a unique method of analysis is developed that considers the action of the environmental variables that act on the ACC installation, allowing therefore determining its final effect on the power installation. The new proposal follows the logical order of the Kröger method, since it is the one with the greatest acceptance and dissemination among researchers and specialists working in this field. In 149 tests carried out, there
A current trend for electrical power generation in areas with water difficult access is the use of air-cooled steam condensers (ACC). Currently in the literature available there is no single method that brings together all factors that are considered in the evaluation of a power plant operating with dry condensation system. In present work a unique method of analysis is developed that considers the action of the environmental variables that act on the ACC installation, allowing therefore to determine its final effect on the power installation. The new proposal follows the logical order of the Kröger method because this is the most widely accepted and disseminated among researchers and specialists working in this field. In a total of 127 tests carried out, there is an average uncertainty in the results obtained with this method of 8.2%, which they are considered sufficiently precise for their use in thermal engineering.
Considering both the incomplete and complete condensation, a conjugate-model-based approach is developed to characterize the distributed thermodynamic development inside finned tube condensers. Applied to an engineering oval finned tube, the approach verifies the in-tube flow pattern as annular and river in incomplete and complete condensation respectively; furthermore, quantifies and compares the varying characteristics of cooling wall temperature, condensation heat flux, condensation HTC, film thickness, wall shear in the two condensation.
In incomplete condensation, the condensation HTC increases slowly with the condensation approaching, unaffected by the steam quality, or film Reynolds number. With regarding complete condensation, an immediate decline of cooling wall temperature, and condensation heat flux and HTC is observed at the end of condensation, one easy-freezing location is marked for the safety operation of condensers, and the backflow of air is found at the vapor outlet. Concerning the phase change section, due to a much lower cooling wall temperature, the complete condensation provides a much greater condensation heat flux, but a nearly equivalent condensation HTC, as comparing to the incomplete mode.
The approach is beneficial in designing an enhanced finned tube and operating a field condenser efficiently.
El presente documento muestra de manera resumida y simple las tendencias principales, en el orden energético, que existen en la actualidad, en cuanto al incremento de la generación eléctrica en la industria azucarera mundial. Se presentan varias tendencias que ya resultan comerciales y otras cuyo nivel de madurez tecnológica es aún insuficiente y que necesitan etapas de investigación y escalado, pero que resultan promisorias. También se han incluido algunas tecnologías energéticas que, si bien se han desarrollado para otras industrias, resultan de interés para un programa inversionista como el que aborda Cuba en este campo.
A numerical simulation was presented to investigate condensation performance of core tubes in air-cooled condenser (ACC). The simulation had been performed in three iso-sectional tubes varying pattern from flat, oval to round. The local heat transfer coefficient (HTC) under the changes of tube inclination angle (β), vapor saturated temperature (Ts), vapor-inlet velocity (U), and sub-cool temperature (ΔTcool) was illustrated to verify the influence of these factors on heat performance of each individual tube. Meanwhile, the comparison on overall heat-flow characteristics among three tubes was also carried out. Regardless of the tube pattern, it was shown that a large β in 0–30°, a high Ts in 316–342 K, and a great U in 103–195 m/s effectively enhanced the local HTC, but a high ΔTcool in 2–8 K reduced it. A nearly twofold increase in Nusselt number was achieved by the round tube compared to flat and oval tubes in a negligible raise of friction coefficient, meanwhile the flat and oval tubes had very close value of performance evaluation criteria. This study highlighted the tube pattern effect to thermal-hydraulic development on the vapor-side of an ACC finned tube system.
For an air-cooled vapor condenser (ACC), environmental wind can cause a large reduction of the flow in the axial fans mainly near the windward side of the air-cooled platform due to cross-flow effects, resulting in a reduction of heat transfer. This leads to an increase in the turbines counter-pressure. This paper proposes a new method to evaluate the effect of wind on the output pressure of the turbine, as well as the effect of the combination of ambient temperature with the direct action of the wind. Finally, the results obtained are given in graph forms and a group of equations are proposed that allow attaining the output pressure of the turbine once ambient temperatures and wind speed are known. These expressions correlate in all cases with a mean error of 11.27% in 89.12% of the experimental data available, and they are considered, therefore, sufficiently precise for their use in thermal engineering.
Finned air-cooling condensers save a significant amount of water in Rankine cycle power plants; however, their heat-removal capability is difficult to predict due to the condensation in finned tubes resulting from the coupled heat transfer between vapor and cooling air fluid. This study develops a conjugate-model-based approach to characterize the thermal-hydraulic development by the transverse flow of vapor and cooling air in a finned tube, and to quantify effects of varying vapor and cooling air operation on the in-tube condensation and out-tube air convection. The approach proposes all uncoupled conditions of a conjugate model on the heat-exchange interfaces, which guarantees that the temperature and heat flux are equal everywhere on the finned tube. Applied to an engineering finned tube, the model verifies that a high vapor mass flux likely reduces the condensation level, and the effect of non-condensable gases with the inlet mass fraction of 0–5% is negligible to the vapor condensation; an increase of cooling air velocity enhances the performance of both vapor condensation and cooling air convection effectively, and a decrease of atmosphere pressure reduces them obviously. The approach is beneficial in designing an enhanced finned tube and operating a field condenser efficiently.
Experimental results for steam condensation in large, flattened-tube air-cooled condensers are presented. Capacity, void fraction, and steam-side pressure drop and heat transfer coefficient are measured, and visualization is performed simultaneously. Capacity and pressure drop results are discussed here. The condenser tube has an elongated-slot cross-section, with inner dimensions of 214 x 16 mm. The tube is 10.7 m long. Steam mass flux ranges from 6-10 kgm-2 s-1 , average air-side velocities were 1.8 and 2.2 m s-1 , and steam condensation pressure ranges from 90-105 kPa. All tests are performed with a horizontal tube and co-current vapor and condensate flow. Three different profiles of cross-flowing air are tested: uniform air flowing upwards, non-uniform air flowing upwards, and uniform air flowing downwards. Reversing airflow direction from upwards to downwards is found to significantly increase condenser capacity. Capacity is also shown to increase with a non-uniform air-velocity profile in comparison to a uniform air-velocity profile. Both of these performance increases are shown to be the result of matching regions of maximum heat transfer coefficient on the air and steam sides. Reducing condensation pressure from 105 to 90 kPa is shown to have no effect on capacity, but is shown to increase steam-side pressure drop, due to an increase in steam velocity.
This study presents the performance evaluation of a combined gas- and steam- turbine cycle power plant (CCPP) integrated with organic Rankine cycle (ORC) and absorption refrigeration cycle (ARC). The attached ORC and ARC units are powered with the flue gas exhaust heat from the CCPP. The evaluation was conducted by performing energy, exergy and environmental sustainability index analysis of the integrated power plant (IPP) and its components. Based on the operating data of an existing CCPP operating in the tropical rain forest region of Nigeria, results of the analysis showed that by utilizing exhaust heat of the CCPP to power an ORC, using R113 as the working fluid, extra 7.5 MW of electricity was generated and by powering an ARC to cool inlet air streams to 15°C in the gas turbine plants, additional 51.1 MW of electricity was generated. The overall effect of integrating ORC and ARC to the CCPP showed that the net power output of the integrated power plant was increased by 9.1%, thermal and exergy efficiencies by 8.7% and 8.8%, respectively, while the total exergy destruction rate and specific fuel consumption reduced by 13.3% and 8.4% respectively. Sustainability index increased by 8.4% which means that the integrated plant has greater environmental sustainability potential over the combined cycle plant.
Conventional power plant condensers operate at unsustainably high cooling water consumption rates (2 – 28 m³ MWh⁻¹). Dry air-cooled condensers (ACCs) can enable reduced water consumption in power plants. However, ACCs are rarely employed because of the substantial decreases in condenser performance and power plant efficiencies compared to wet-cooled systems. ACC studies typically focus on air-side transport, assuming that the effects of steam-side pressure drop and thermal resistance are small. The objective of the present investigation is to scrutinize this assumption – quantifying the influence of steam-side effects on ACC operation. A detailed model of a representative ACC is formulated. Model results demonstrate that condensation heat transfer and pressure drop are poorly characterized at ACC operating conditions. Predicted power plant efficiency varies by 0.7% with different condensation heat transfer models. Additionally, predicted plant efficiencies vary depending on which pressure drop correlation is employed. The differences are exacerbated at low steam saturation pressures (∼4 kPa), where the cycle efficiencies range from 36.0% and 37.7% between different pressure drop correlations. Results from this study indicate that both steam side and air-side effects must be considered to improve ACC performance. Some methods for enhancing in-tube condensation are mentioned, and future ACC research needs are discussed.
The traditional back pressure regulation of turbine is influenced more seriously by ambient wind and temperature, especially the hot air reflow and high temperature effect on the axial fans of the air-cooled condensers. This variation would result in the cooling capacity of the fans decreasing and the power consumption increasing. The grey difference incremental correlation method is proposed for considering the back pressure regulation problem from a single condenser cell perspective, and analyze the influence on the heat rejection when processing the speed regulation of the axial fans, then the relationship between the heat rejection increment and the influence of the back pressure will be obtained. The flow and temperature fields of the air-cooled condensers can be obtained by applying the CFD method, and the different back pressure in the different fan speed will be calculated. The results show that, larger the fans ventilation rates will not necessarily cause higher the heat rejection of the finned tube bundle. Reasonably improve the speed of the higher relational degree fans can effectively reduce the turbine back pressure and save energy.
The Λ-frame air-cooled condenser (ΛACC) is widely applied by people, but it is also the main reason of the uneven distribution of internal air flow and temperature field in the air-cooled condenser (ACC). In order to solve these problems and make the air-cooled unit running more economically, safely and efficiently, heat transfer characteristics of new types of ACC are researched, which is of significance for improving traditional direct air cooling technology. Taking the 600MW unit model of a thermal power plant as the comparative object, innovation is made to change the heat transfer surface of Λ-frame into truncated cone-shaped. By means of the numerical simulation, the relationship between the flow and heat transfer characteristics and the top baffle porosity of the truncated cone-shaped air-cooled condenser (TCACC) is studied, and the optimal baffle porosity for heat transfer and safety is got. Then, the effect of the shapes of baffle on the heat transfer characteristics of the TCACC is studied, and the shapes of which are optimized. Comparisons for a series of ACCs in different fan inlet air volumes and temperatures are made, and the optimized ACC is obtained for heat transfer and safety finally. All these we have done are going to provide some significant theory evidence for improving of direct air cooling technology.
A hybrid structural system designed for use in large thermal power plants in China to house air-cooled condenser systems is investigated. The hybrid structure consists of a series of metal A-frames resting on a steel space truss supported by an array of reinforced concrete columns. To gain a better understanding of this structural system, a one-eighth (1:8) scale test structure modeled after a prototype structure was constructed and tested. The test structure was subjected to both free vibration and forced excitation tests with the following objectives: (1) determining its modal properties and seismic response characteristics, (2) gaining insight into its response and most probable failure modes under dynamic excitations, (3) obtaining some useful experimental data for future research, and (4) providing important data to complement the Chinese seismic design code as well as to guide the design of this type of structure in practical engineering applications. The free vibration tests were carried out by inducing an initial displacement to the structure and measuring its natural frequencies and mode shapes. The forced excitation tests consist of a series of quasi-static and pseudo-dynamic tests. For the quasi-static tests, 10 reciprocating displacement excitations with peaks ranging from 6 to 100 mm were used, and for the pseudo-dynamic tests, six ground motions with scaled maximum accelerations ranging from 50 to 800 cm/s² were employed. Based on the results of these tests, modal properties of the hybrid structure such as natural frequencies, mode shapes, and equivalent damping ratios, as well as some seismic response characteristics such as seismic shears, accelerations, deformations, interstory drifts, roof drifts, and hold-down forces were determined and presented. In addition, nonlinear analysis of the test and prototype structures was conducted using the finite element software ANSYS and compared with the test results. Detailed damage inspection was performed, and important findings were summarized.
An analytical method is presented to evaluate the air flow rate required in an air-cooled heat exchanger used in a propane pre-cooling cycle operating in an LNG (liquefied natural gas) plant. With variable ambient air inlet temperature, the air flow rate is to be increased or decreased so as to assure and maintain good performance of the operating air-cooled heat exchanger at the designed parameters and specifications. This analytical approach accounts for the variations in both heat load and ambient air inlet temperature. The ambient air inlet temperature is modeled analytically by simplified periodic relations. Thus, a complete analytical method is described so as to manage the problem of determining and accordingly regulate, either manually or automatically, the flow rate of air across the finned tubes of the air-cooled heat exchanger and thus, controls the process fluid outlet temperature required for the air-cooled heat exchangers for both cases of constant and varying heat loads and ambient air inlet temperatures. Numerical results are obtained showing the performance of the air-cooled heat exchanger of a propane cycle which cools both NG (natural gas) and MR (mixed refrigerant) streams in the LNG plant located at Damietta, Egypt. The inlet air temperature variation in the summer time has a considerable effect on the required air mass flow rate, while its influence becomes relatively less pronounced in winter.
Purpose
In this paper, a first prototype of the innovative modular air-cooled condenser (MACC) proposed under the EU-funded MACCSol research project (Development and verification of a novel modular air cooled condenser for enhanced concentrated solar power generation) is compared with a water-cooled condenser (WCC) and an air-cooled condenser (ACC) in a reference concentrated solar power (CSP) plant. The aim is to evaluate the complete environmental profile of each cooling option and to highlight the differences in terms of impacts.
Diminishing fossil fuel reserves and a growing collective environmental awareness has led to the development of alternative methods of power generation such as Concentrated Solar Power (CSP). Although almost all existing CSP plants currently use water-cooled condensers, limited water supplies in the designated desert regions for such power plants, the high costs associated with providing cooling water and environmental considerations will all restrict the future use of water-cooled condensers. Air-cooled condensers (ACCs) are therefore proposed, despite evidence to suggest that they suffer from significant inefficiencies [1]. It has been suggested that a modular design, addressed in this paper, could offer solutions to issues with current ACC technologies. To fully characterise the modular ACC design it is necessary to quantify the steam-side characteristics. A series of tests were performed under vacuum conditions representative of an operational condenser. The condenser vacuum was measured for a series of incremental fan rotational speeds, to determine both the qualitative and quantitative relationship between fan speed and condenser pressure. Results indicate that for a given steam mass flow rate, the condenser pressure decreases with increasing fan rotational speed. Furthermore, the choice of vacuum pump, used to displace air leakages, was shown to have a significant influence on the steam-side response. Larger displacement-capacity vacuum pumps permit lower condenser pressures. The steam condensation pressure drop through the condenser tubes was also measured. Results for the measured pressure drop revealed a large level of momentum recovery, which is not uncommon in steam condensation processes. Experimental frictional pressure drops were determined and these compared favourably with certain two-phase frictional pressure drop correlations. In particular, the Lockhart & Martinelli correlation was found to be most capable of predicting the frictional pressure drop trends encountered during testing. The large level of agreement between the measurements and predictions provide confidence in future use of the Lockhart & Martinelli correlation to predict frictional pressure losses.
Limited water supplies in proposed concentrated solar power (CSP) plant locations have instigated the need for air-cooling of the condensers in the Rankine cycle. The current industry standard for air-cooling in power plants is the A-frame air-cooled condenser (ACC), the installation of which has increased exponentially in the last 15 years. This has occurred despite the fact they suffer from significant inefficiencies and weather effects. This paper introduces a modular air-cooled condenser (MACC) design which seeks to minimise these inefficiencies. A thermodynamic analysis is carried-out to determine the outcome of installing this MACC design in a CSP plant. Firstly, a series of measurements performed on a full-scale prototype MACC under vacuum conditions representative of an operational ACC are presented. Condenser temperature and pressure were measured as fan speed was varied, for a range of steam flow rates, to determine the qualitative and quantitative relationship between fan rotational speed and condenser steam-side conditions. Results show that for a fixed steam flow rate and constant ambient temperature, condenser temperature and pressure decrease as fan speed increases. The relationships, developed from the measurements, between fan speed and condenser temperature-pressure were then used to evaluate the gross output from a 50 MW steam turbine and, ultimately, evaluate the net plant output. Results show that increasing fan speed leads to an increase in plant output up until a certain point, at which further increases in output are offset by larger fan power consumption rates. Thus, an optimum operating point exists. The effects of ambient temperature were also examined and were seen to have a significant impact on firstly, steam-side conditions and consequently, plant output. Increases in ambient reduce plant output. However, by varying the fan speed to achieve the optimum operating point for any given ambient, the losses can be minimised.
In this work, a parametric optimization analysis of various innovative modular air-cooled condenser systems is carried out in order to identify the optimum system configuration and size to be used as the cooling system in a 50MWe parabolic trough concentrated solar power (CSP) plant. The optimization analysis is conducted individually on a total of 17 different configurations and on a total of 8 different condenser sizes for each configuration. The results identify the optimum air cooled condenser configuration and size that can achieve the minimum CSP plant electricity unit cost.
The problem of laminar film condensation of vapor in the presence of high concentration non-condensable gas such as humid air flowing in a vertical pipe under laminar forced convection conditions is formulated theoretically. The vapor condensing at dew point temperature releases both sensible and latent heats and diffuses on to the surface of the pipe through a non-condensable gas film. Thus it is treated as combined heat and mass transfer problem governed by mass, momentum and energy balance equations for the vapor–gas mixture and diffusion equation for the vapor species. The flow of the falling condensate film is governed by the momentum and energy balance equations. The temperature at the gas-to-liquid interface, at which the condensation takes place, is estimated with the help of the heat balance and mass balance equations at the interface. The local and average values of the condensation Nusselt number, condensate Reynolds number, gas–liquid interface temperature and pressure drop are estimated from the numerical results for different values of the system parameters at inlet, such as relative humidity, temperature of vapor–gas mixture, gas phase Reynolds number and total pressure. The gas phase convection Nusselt and Sherwood numbers are also computed from numerical results. The predictions of the present study are compared with the experimental data available in literature, and the agreement is found to be reasonably good. An implicit pressure correction method developed by the authors is used in solving the momentum balance equation for the gas phase.
A theory has been devised for predicting condensation heat transfer in the presence of a noncondensable gas. The analysis is based on the conservation laws alone and does not utilize empirical data. It is shown that the presence of a very small amount of noncondensable gas in the bulk of the vapor can cause a large buildup of the noncondensable at the liquid-vapor interface. A consequence of this buildup is that the partial pressure of the vapor at the interface is reduced. This, in turn, lowers the temperature at which the vapor condenses and diminishes the effective thermal driving force. Heat-transfer reductions of well over fifty percent may be brought about by the presence of the noncondensable. The predictions of the analysis are compared with condensation heat-transfer measurements for steam with air as noncondensable. The agreement between theory and experiment is satisfactory.
The use of air cooled condensers in power generation is increasing in many arid regions of the world. The classical A-frame condenser design is implemented in most new installations despite significant empirical evidence that such designs suffer from poor efficiencies and weather effects, and therefore provide significant scope for improvements. An inefficient condenser results in higher back pressure on the turbine, over-sized condensers and increased fan power. This paper addresses the flow distribution from an air cooled condenser for a ∼400MW gas and steam power plant. The results indicate that the flow patterns from the large scale fans results in a severe inhomogeneous distribution of cooling on the condenser fins. These region of high and low velocity are closely related to the outlet flow pattern from the fans, where in the hub region the air mass flow rate is reduced, while in the tip region it is increased. These measurements provide an excellent basis for both understanding the existing deficiencies of the A-frame designs and moreover provide direction for improved designs in the future.
For the complex system, there are many influencing factors of the reliability, and apart of the factors can only be assessed qualitatively. Furthermore, the complex system is composed by different type sub-systems. So it is difficult to allocate the reliability of system to every subsystem by traditional reliability allocation method. So, a new reliability allocation method which based on the fuzzy decision is proposed. The basic idea and the steps are introduced. And the formula for calculating the reliability of sub-system is defined. At last, an example is calculated by this method. It is proved that the result is accord with the principles of reliability allocation completely.
Infrared thermography technique was employed to monitor overall as well as local surface temperature distributions of air-cooled condensers (ACC) in order to investigate the influence of ambient air temperatures, surface fouling of fin-tube bundles and natural wind on performance of air-cooled power generating units. Three typical direct air-cooled power generating units in operation in north China were selected as the research objects, which are 300 MW sub-critical units with ACC of three-row fin-tube bundles, 600 MW sub-critical unit and 600 MW supercritical unit with ACC of single-row fin-tube bundle respectively. The monitoring results revealed that the counterflow ACC units were vulnerable to freezing in winter. The results also cast light on the uneven steam flow distributions inside fin-tubes of different parallel-flow ACC units, especially when the redundant cooling areas of ACC Island were large. The characteristics of surface temperature distributions were obtained in different regions of ACC units under surface fouling conditions. It was also acquired that the gentle natural wind can have an impact on the heat transfer of most cooling areas of ACC island by forming overhead vortex. This should be paid attention to as well as besides the effect of thermal recirculation under large natural wind conditions. The present study may benefit the optimal operation of air-cooled power generating units.
Because of the current environmental requirements for zero discharge from power plants and scarcity of water, the cooling tower—a proven and industry-recognized conventional option for combined cycle application heat sinks—is being scrutinized by designers, developers, operators, and regulatory agencies. This paper is a guideline to selecting the most appropriate solution for the plant heat sink based on water availability, site location, and wastewater disposal requirements. The paper discusses wet as well as dry cooling systems and evaluates the impact of heat sink selection for cogeneration applications and merchant power plant cycling operation mode. For each proposed option, the performance, relative costs, and noise issues will be presented.
A three-dimensional analysis of the combined heat and mass transfer between a moist air turbulent flow and a cooled solid surface was carried out. A turbulent boundary layer was modelled using the Wilcox k–ω turbulence model. Numerical results for the extended surface efficiency under various psychrometric conditions were obtained by solving simultaneously coupled equations of the fluid and the solid. The results show that variations in moist air parameters have a significant effect on the extended surface efficiency. It is shown that an increase in the inlet air humidity decreases the surface efficiency.
The effect of inlet flow distortions on fan performance in forced-draught air-cooled heat exchangers (ACHEs) is investigated numerically and experimentally. By varying the distance between the ACHE fan platform and the ground level, significant changes in air volume flow rate are observed. Three different fan inlet shrouds are considered and recommendations towards designing and evaluating the performance of an ACHE are made. The effect of different lengths of a cylindrical fan inlet shroud, as well as the effect of cylindrical sections as part of a conical and a bell-mouth inlet shroud, is also investigated. The results show that a critical length for both the cylindrical inlet shroud and the cylindrical sections of the conical and bell-mouth inlet shrouds can be obtained for optimal fan performance.
In order to improve the system running economics of the direct air-cooled unit, based on the thermodynamic model of the air-cooled system, through considering the steam turbine power and the consumption power of fan, this article has researched the optimal back-pressure of the unit in theory under the running conditions, and given the basic law about the optimal back-pressure affected by the corresponding main factors. Thus, the results of studying will provide helpful guidance for the cold-end optimization and economical running of the direct air-cooled thermal power plants.
Utility power producers are being driven by the inherently high efficiency and attractive installed cost of Combined Cycle Power Plants (CCPP) to consider them as the dominant choice for least-cost power. However, in a CCPP the power capability is significantly affected by the ambient temperature [Sue DC, Chuang CC, Lin PH. Performance improvement for gas turbine combined cycle power plants (GTCCPP) in Taiwan. In: Johnson D, editor. Electric power. Fourth annual conference and exhibition, vol. 4A; 2004. St Louis, MI, USA: American Center. p. 1–15. [1]], condenser pressure and power demand. In the Power Purchase Agreements (PPA) written in Taiwan, the capacity payment is based on the guaranteed power output during the operating period. Therefore, operating the CCPP at the highest performance and maintaining the guaranteed or contractual power output are important factors to get the full capacity and energy payments from the power purchaser and reduce the fuel and operating costs for the power producer.
This third edition is an update of the second edition published in 1964. New data and more modern theoretical solutions for flow in the simple geometries are included, although this edition does not differ radically from the second edition. It contains basic test data for eleven new surface configurations, including some of the very compact ceramic matrices. Al dimensions are given in both the English and the Systeme International (SI) system of units.
This book presents a complete introduction to the fundamentals of the theory and application of thermodynamics. Revisions include a new chapter on the sources, uses and management of energy as well as major updating of the chapters on internal combustion engines and psychometry. It features new sections on extended surfaces, two-dimensional and transient conduction using finite difference methods, and the NTU method for heat exchanger design. It also stresses the application of theory to real situations and applies principles to practical engineering problems.
The effect of nonuniform (or maldistributed) inlet airflow and temperature on the thermal performance of cross-flow air-cooled heat exchangers, with both fluids unmixed, and taking into consideration differences in performance characteristics of individual tube rows, is addressed in this article. The latter may be due to different fin pitches or other geometric variations or row effects due to changes in air turbulence. Downstream tube rows in such a multirow tube bundle experience higher performance reductions than the tube row at the air inlet. A nonuniform air velocity distribution to a tube row leaves the row with a distorted temperature profile. This temperature nonuniformity increases as the air passes through subsequent tube rows, and causes the downstream rows to be progressively less effective. The present analysis is used to evaluate the performance of the individual tube rows and ultimately the entire bundle. Velocity distributions which have been measured on air-cooled heat exchanger models are employed in the analysis in order to determine to what extent airflow maldistribution reduces exchanger performance. It is found that maldistribution occurring in well-designed air-cooled heat exchangers reduces the thermal performance by only a few percent.
In order to minimize the hot air recirculation (HAR) to ensure normal operation of the air-cooled condensers (ACC) system, the hot air recirculation phenomenon and its dependence on ambient winds are numerically simulated by using the computational fluid dynamics code, FLUENT. Under the constant ambient temperature, the effects of different wind speed and wind direction on the HAR are qualitatively considered by applying the concept of the hot recirculation rate (HRR). The mechanism of occurrence of hot air recirculation are presented and analyzed. It was found that when considering about the existing and normally operating power plants, the HAR is more sensitive to wind direction and wind speed. Based on the above results, two improved measures increasing the wind-wall height and accelerating the rotational speed of the fans near the edge of the ACC platform are developed to effectively reduce the hot air recirculation.
The expression Y = (1 + Zn)1/n where Y and Z are expressed in terms of the solutions for asymptotically large and small values of the independent variable is shown to be remarkably successful in correlating rates of transfer for processes which vary uniformly between these limiting cases. The arbitrary exponent n can be evaluated simply from plots of Y versus Z and Y/Z versus 1/Z. The expression is quite insensitive to the choice of n and the closest integral value can be chosen for simplicity. The process of correlation can be repeated for additional variables in series. Illustrative applications are presented only for flow, conduction, forced convection, and free convection, but the expression and procedure are applicable to any phenomenon which varies uniformly between known, limiting solutions.
With the rapid development of virtual instruments and meteorological automation, combining virtual technology with meteorological measurement is becoming an important development direction of meteorological instruments. It can realize the data acquisition of temperature and humidity as well as data transmission, analysis and display, with the development software of virtual instruments - LabVIEW, sensors, wireless transmission modules, which receive and send the data from sensors, and so on, in addition to providing users with control and display panel as well as historic data inquire. Users can change the function of the system so that it saves a lot of labor power and material resources so that it makes measurement more convenient and fast.
The recirculation of hot exhaust air and its dependence on wind direction was investigated as a cause of reduced efficiency in an air-cooled condenser (ACC). A method of simulating exhaust air recirculation at an ACC platform using a wind tunnel is presented, and applied to a proposed ACC addition at an existing power plant. It was found that wind speed and the height of an ACC platform have a significant impact on recirculation. Wind direction was also found to be significant, due to the interference of the buildings adjacent to the ACC platform. The mechanisms that cause recirculation are presented and analyzed, and the characteristics of the recirculating flow are described. It was found that when considering additions to existing power plants, the distance of the new ACC and power plant from the original buildings and structures has only a minor effect on the recirculation of the added ACC platform. Wind tunnel simulation is recommended in the initial design stage of new or renovated power plants with ACC systems to minimize exhaust recirculation.
The influence of wind on fan performance and recirculation in a forced draught air-cooled heat exchanger (ACHE) bank is investigated numerically. Winds blowing across and parallel to the longitudinal axis (long axis) of an ACHE bank are considered. It is found that cross winds significantly reduce the air volume flow rate that is delivered by the up-wind fans, while winds along the longitudinal axis cause increased hot plume air recirculation along the sides of the ACHE bank.
Experimental and theoretical investigations were conducted for the film condensation with noncondensable gas in a vertical tube. Condensation experiments were performed for a steam–air mixture in a vertical tube submerged in a water pool where the heat from the condenser tube was removed through a boiling heat transfer. Degradation of the condensation with noncondensable gas was investigated. A heat and mass analogy model for the annular filmwise condensation with noncondensable gas was developed. In the steam–air mixture region, general momentum, heat and mass transport relations derived by analytic method were used with the consideration of surface suction effect. The predictions from the model were compared with the experimental data and the agreement was satisfactory.
Selection Criteria Based on Operating Parameters General Selection Guidelines for Major Exchanger Types Some Quantitative Considerations Summary References Review Questions Problems
Thesis (Ph. D.)--Massachusetts Institute of Technology, Dept. of Mechanical Engineering, 1960. Vita. Includes bibliographical references (leaves 107-110). by John C. Chato. Ph.D.
An analytical model is presented that predicts the average heat
transfer rate for forced convection air cooled plate fin heat sinks for
use in the design and selection of heat sinks for electronics
applications. Using a composite solution based on the limiting cases of
fully-developed and developing flow between isothermal parallel plates,
the average Nusselt number can be calculated as a function of the heat
sink geometry and fluid velocity. The resulting model is applicable for
the full range of Reynolds number, 0.1<Reb*<100, and
accurately predicts the experimental results to within an RMS difference
of 2.1%
The specification and design of heat sinks for electronic
applications is not easily accomplished through the use of conventional
thermal analysis tools because “optimized” geometric and
boundary conditions are not known a priori. A procedure is presented
that allows the simultaneous optimization of heat sink design parameters
based on a minimization of the entropy generation associated with heat
transfer and fluid friction. All relevant design parameters for plate
fin heat sinks, including geometric parameters, heat dissipation,
material properties and flow conditions can be simultaneously optimized
to characterize a heat sink that minimizes entropy generation and in
turn results in a minimum operating temperature. In addition, a novel
approach for incorporating forced convection through the specification
of a fan curve is integrated into the optimization procedure, providing
a link between optimized design parameters and the system operating
point. Examples are presented that demonstrate the robust nature of the
model for conditions typically found in electronic applications. The
model is shown to converge to a unique solution that gives the optimized
design conditions for the imposed problem constraints
Applied Thermodynamics for Engineering Technologists
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Reams, Steam-side charac-terisation of a modular air-cooled condenser, in: ASME 2012 International Mechanical Engineering Congress and Exposition
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Analysis of Laminar Forced-convection Heat Transfer in Entrance Region of Flat Rectangular Ducts, National Advisory Committee for Aeronautics
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E. Sparrow, Analysis of Laminar Forced-convection Heat Transfer in Entrance
Region of Flat Rectangular Ducts, National Advisory Committee for Aeronautics, 1955.
Local Heat-transfer Coefficients and Static Pressures for Condensation of High-velocity Steam within a Tube, National Aeronautics and Space Administration
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J.H. Goodykoontz, R.G. Dorsch, Local Heat-transfer Coefficients and Static
Pressures for Condensation of High-velocity Steam within a Tube, National
Aeronautics and Space Administration, 1967.
Performance characteristics of an air-cooled condenser under ambient conditions
- A R V Ramani
- B Paul
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A.R.V. Ramani, B. Paul, D. Saparia, Performance characteristics of an air-cooled
condenser under ambient conditions, in: International Conference on Current
Trends in Technology, IEEE, Ahmedabad, India, 2011.
Steam-side characterisation of a modular air-cooled condenser
- A O'donovan
- R Grimes
- E Walsh
- J Moore
- N Reams
A. O'Donovan, R. Grimes, E. Walsh, J. Moore, N. Reams, Steam-side characterisation of a modular air-cooled condenser, in: ASME 2012 International
Mechanical Engineering Congress and Exposition, American Society of Mechanical Engineers, Houston, 2012, pp. 1719e1730.