Letteratura scientifica selezionata sul tema "Indirect Evaporation"
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Articoli di riviste sul tema "Indirect Evaporation":
1
Cichoń, Aleksandra, Anna Pacak, Demis Pandelidis e Sergey Anisimov. "Reducing energy consumption of air-conditioning systems in moderate climates by applying indirect evaporative cooling". E3S Web of Conferences 44 (2018): 00019. http://dx.doi.org/10.1051/e3sconf/20184400019.
Abstract (sommario):
This paper investigates the potential of applying an indirect evaporative cooler for heat recovery in air conditioning systems in moderate climates. The counter-flow indirect evaporative heat and mass exchanger is compared with commonly used recuperation unit in terms of achieved energy. The performance analysis of the indirect evaporative exchanger is carried out with original ε-NTU-model considering condensation from treated air. It was found that the indirect evaporative exchanger employed as a heat recovery device, allows to obtain higher performance than conventional recuperator. Additional energy savings potential is related with utilizing the potential of water evaporation to pre-cool the outdoor air. It is also stated that there is a high potential of reusing condensate that forms in product channels of the indirect evaporative exchanger and in the vapour-compression unit and delivering it to the working part of the indirect evaporative exchanger.
2
Budagovskyi, Anatolij, e Viliam Novák. "THEORY OF EVAPOTRANSPIRATION: 2. Soil and intercepted water evaporation". Journal of Hydrology and Hydromechanics 59, n. 2 (1 giugno 2011): 73–84. http://dx.doi.org/10.2478/v10098-011-0006-8.
Abstract (sommario):
THEORY OF EVAPOTRANSPIRATION: 2. Soil and intercepted water evaporationEvaporation of water from the soil is described and quantified. Formation of the soil dry surface layer is quantitatively described, as a process resulting from the difference between the evaporation and upward soil water flux to the soil evaporating level. The results of evaporation analysis are generalized even for the case of water evaporation from the soil under canopy and interaction between evaporation rate and canopy transpiration is accounted for. Relationships describing evapotranspiration increase due to evaporation of the water intercepted by canopy are presented. Indirect methods of evapotranspiration estimation are discussed, based on the measured temperature profiles and of the air humidity, as well as of the net radiation and the soil heat fluxes.
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Asemi, Hamidreza, Rahim Zahedi e Sareh Daneshgar. "Theoretical analysis of the performance and optimization of indirect flat evaporative coolers". Future Energy 2, n. 1 (15 novembre 2022): 9–14. http://dx.doi.org/10.55670/fpll.fuen.2.1.2.
Abstract (sommario):
External-cooling indirect evaporative coolers with different configurations and working air sources are incomprehensively analyzed and compared so far. This paper investigates the mechanism and theory of operation of indirect flat-panel evaporative coolers based on X-analysis. Then, based on the second law of thermodynamics analysis, the entropy production rate of the flat-plate heat exchanger of the cooler is calculated. As a result of this analysis, the optimal energy efficiency-evaporation efficiency and cooling capacity values are presented in terms of effective parameters in the design.
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Kim, Nae-Hyun. "Modeling of Heat and Moisture Transfer in an Indirect Evaporative Cooler Made of Plastic Film/Paper". International Journal of Air-Conditioning and Refrigeration 23, n. 04 (dicembre 2015): 1550026. http://dx.doi.org/10.1142/s2010132515500261.
Abstract (sommario):
In this study, a thermal model of indirect evaporative cooler (IEC) was constructed. An IEC made of plastic film/paper composite was tested, and the results were compared with predictions of the model. In adddition, parametric study was conducted using the model. The model was based on [Formula: see text]-NTU analysis of wet surface heat and mass transfer. Especially, the model considered air leakage, nonuniform overall heat transfer coefficient and entrance region. Comparison of the predictions of the model with limited experimental data showed favorable results. Parametric study using the model showed that increase of the dry and wet channel inlet temperature resulted in increase of the indirect evaporation efficiency. The increase of the wet channel inlet humidity also increases the efficiency. The dry channel inlet humidity, however, was independent of the efficiency. The indirect evaporation efficiency and the pressure drop increased as the IEC size increased. However, they decreased as the channel height increased.
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CHOWDHURY, A., H. P. DAS e S. D. GAIKWAD. "Determination of relative contribution of different meteorological elements on evaporation". MAUSAM 50, n. 4 (17 dicembre 2021): 365–74. http://dx.doi.org/10.54302/mausam.v50i4.1949.
Abstract (sommario):
The present study deals with influence of radiation, maximum temperature, hours of bright sunshine, relative humidity and surface wind on evaporation at Calcutta, Pune and New Delhi. Daily data from 1991-94 of January, May, June, July and October have been utilized. Direct and indirect influence of the weather factors have been determined through "path analysis" and discussed. Multiple regression equations have also been developed with evaporation as the dependent variable and the above five weather parameters as independent variables.
The results reveal that radiation and maximum temperature are the two most important parameters which enhance evaporation. Most of their effect is direct though in some cases their interaction with relative humidity or wind also contribute significantly to evaporation. Humidity and surface wind, generally, do not significantly contribute directly to evaporation; their effect is manifested through interaction with maximum temperature, indirectly.
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Dalaf, Adham Ahmed, Maki Haj Zidan e Aadel A. Al-Kumait. "Improving the Behavior of Indirect Evaporative Cooler*". Journal of Advanced Sciences and Engineering Technologies 1, n. 3 (26 dicembre 2021): 11–17. http://dx.doi.org/10.32441/jaset.01.03.02.
Abstract (sommario):
ndirect evaporative cooling is one of the technologies currently used to build highly efficient air conditioning systems and low power consumption. A computer program was created to predict the effectiveness of an indirect-evaporation cooling system which operates based on Maisotsenko cycle (M-cycle) to determine the environmental conditions and proper system design. Several variables that affect the performance of the system have been studied; the amount of volumetric flow of air ranged from (1050 cfm) to (1550 cfm) for the dry side, and changing from 700 cfm to 1200 cfm from the wet side. With respect to design variables, the length of the channel changed from 50 cm to 100 cm. For environmental variables, the effect of changes in dry and wet temperature on system performance had been studied. The experiment was conducted in mid-June over 24 hours. The results showed that the best air supply provided for the best performance of the system is (1050cfm) for the dry side, while the wet side was (900 cfm), when the length of the channel is 80 cm. The results showed the possibility of applying this system in (Tikrit) because it is characterized by its hot and dry climate in the summer, as evaporative cooling efficiency increases in hot, dry climates
© 2018 JASET, International Scholars and Researchers Association
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Shevnina, Elena, Miguel Potes, Timo Vihma, Tuomas Naakka, Pankaj Ramji Dhote e Praveen Kumar Thakur. "Evaporation over a glacial lake in Antarctica". Cryosphere 16, n. 8 (2 agosto 2022): 3101–21. http://dx.doi.org/10.5194/tc-16-3101-2022.
Abstract (sommario):
Abstract. The study provides estimates of summertime evaporation over a glacial lake located in the Schirmacher oasis, Dronning Maud Land, East Antarctica. Lake Zub (alternately named Lake Priyadarshini and referred to throughout as Lake Zub/Priyadarshini) is the second-largest lake in the oasis, and its maximum depth is 6 m. The lake is also among the warmest glacial lakes in the oasis, and it is free of ice during almost 2 summer months. The summertime evaporation over the ice-free lake was measured using the eddy covariance method and estimated on the basis of five indirect methods (bulk-aerodynamic method and four combination equations). We used meteorological and hydrological measurements collected during a field experiment carried out in 2018. The eddy covariance method was considered the most accurate, and the evaporation was estimated to be 114 mm for the period from 1 January to 7 February 2018 (38 d) on the basis of this method. The average daily evaporation was 3.0 mm d−1 in January 2018. During the experiment period, the largest changes in daily evaporation were driven by synoptic-scale atmospheric processes rather than local katabatic winds. The bulk-aerodynamic method suggests the average daily evaporation is 2.0 mm d−1, which is 32 % less than the results based on the eddy covariance method. The bulk-aerodynamic method is much better in producing the day-to-day variations in evaporation compared to the combination equations. All selected combination equations underestimated the evaporation over the lake by 40 %–72 %. The scope of the uncertainties inherent in the indirect methods does not allow us to apply them to estimate the daily evaporation over Lake Zub/Priyadarshini. We suggested a new combination equation to evaluate the summertime evaporation over the lake's surface using meteorological observations from the nearest site. The performance of the new equation is better than the performance of the indirect methods considered. With this equation, the evaporation over the period of the experiment was 124 mm, which is only 9 % larger than the result according to the eddy covariance method.
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Sun, Tiezhu, Xiaojun Huang, Caihang Liang, Riming Liu e Xiang Huang. "Prediction and Analysis of Dew Point Indirect Evaporative Cooler Performance by Artificial Neural Network Method". Energies 15, n. 13 (25 giugno 2022): 4673. http://dx.doi.org/10.3390/en15134673.
Abstract (sommario):
The artificial neural network method has been widely applied to the performance prediction of fillers and evaporative coolers, but its application to the dew point indirect evaporative coolers is rare. To fill this research gap, a novel performance prediction model for dew point indirect evaporative cooler based on back propagation neural network was established using Matlab2018. Simulation based on the test date in the moderately humid region of Yulin City (Shaanxi Province, China) finds that: the root mean square error of the evaporation efficiency of the back propagation model is 3.1367, and the r2 is 0.9659, which is within the acceptable error range. However, the relative error of individual data (sample 7) is a little bit large, which is close to 10%. In order to improve the accuracy of the back propagation model, an optimized model based on particle swarm optimization was established. The relative error of the optimized model is generally smaller than that of the BP neural network especially for sample 7. It is concluded that the optimized artificial neural network is more suitable for solving the performance prediction problem of dew point indirect evaporative cooling units.
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Jayakody, Harith, Raya Al-Dadah e Saad Mahmoud. "Cryogenic Energy for Indirect Freeze Desalination—Numerical and Experimental Investigation". Processes 8, n. 1 (21 dicembre 2019): 19. http://dx.doi.org/10.3390/pr8010019.
Abstract (sommario):
Renewed interest in freeze desalination has emerged due to its advantages over other desalination technologies. A major advantage of the freeze desalination process over evaporative methods is its lower energy consumption (latent heat of freezing is 333.5 kJ/kg and latent heat of evaporation is 2256.7 kJ/kg). Cryogenic fluids like LN2/LAir are emerging as an effective energy storage medium to maximise utilisation of intermittent renewable energy sources. The recovery of this stored cold energy has the potential to be used for freeze desalination. Computational Fluid Dynamics (CFD) modelling was developed to simulate the evaporation of liquid nitrogen to simultaneously conduct freeze desalination to investigate the feasibility of using cryogenic energy for freeze desalination. This integrated CFD model was validated using experimental heat exchanger test facility constructed, to evaporate liquid nitrogen to supply the cooling required for freezing. Parametric study on the LN2 flow rate to observe the volume of ice obtained was also examined using CFD, where increasing the velocity of LN2 by 6 times, increased the volume of ice obtained by 4.3 times. A number of freezing stages were required in order to reduce the ice salinity from 1.5% down to 0.1% as regarded by the World Health Organisation (WHO) as safe to drink. In the cryogenic desalination test rig, approximately 1.35 L of liquid nitrogen was required to reduce the ice salinity from 1.5% to less than 0.1%. Furthermore, the above results illustrate the potential of using the cold energy of cryogenic fluids such as Liquified Natural Gas (LNG) and LN2/LAir for freeze desalination applications as most cold energy during LNG regasification has been unexploited today.
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Hashim, Rasha, Salman Hammdi e Adel Eidan. "Evaporative Cooling: A Review of its Types and Modeling". Basrah journal for engineering science 22, n. 1 (24 aprile 2022): 36–47. http://dx.doi.org/10.33971/bjes.22.1.5.
Abstract (sommario):
Evaporative cooling is a widely used energy-saving and environmentally friendly cooling technology. Evaporative cooling can be defined as a mass and heat transfer process in which the air is cooled by the evaporation of water and as a result a large amount of heat is transferred from the air to the water and thus the air temperature decreases. Evaporative cooling is mainly used in many cooling technologies used in buildings, factories, agricultural in addition to it is used industrially in cooling towers, evaporative condensers, humidification, and humidity control applications. Evaporative cooling is divided into direct evaporative cooling and indirect evaporative cooling, as well as water evaporative cooling and air evaporative cooling. This paper reviews the most important developments and technologies in evaporative cooling that lead to lower energy consumption and provide suitable cooling comfort.
Tesi sul tema "Indirect Evaporation":
1
Abada, Djallel. "Intégration d'un Système de Rafraichissement par Évaporation Dans le Bâtiment". Electronic Thesis or Diss., Reims, 2021. http://www.theses.fr/2021REIMS007.
Abstract (sommario):
Avec la croissance de la population et le processus d'urbanisation effrénée qui touchent presque la totalité des centres urbains dans le monde, le besoin d'énergie pour le rafraîchissement des espaces ne cesse d'augmenter, en particulier dans les pays émergeants. Cette recherche est orientée vers les techniques relatives aux nouvelles méthodes de rafraîchissement à moindre coût et écologiques. L’étude a dévoilé que les systèmes de rafraîchissement par évaporation indirect à point de rosée comptent parmi les plus prometteurs. Leur capacité à utiliser l'évaporation de l'eau pour absorber la chaleur afin d'abaisser la température de l'air sans ajout de l’humidité, est un principe de rafraîchissement peu énergivore et avec un minimum d’impacts sur l'environnement. À partir de nos investigations, il a été possible de vérifier que le système étudié pouvait atteindre des efficacités plus élevées que les systèmes à évaporation indirects typiques à moindre coût. Son efficacité dépend en grande partie de la géométrie des canaux, du débit et de la température de l'air d'admission, de l'humidité et du rapport de l’air secondaire, mais moins de la température de l'eau d'alimentation du substrat. Il a été également conclu que le système de point de rosée convenait à la plupart des régions à climat sec, doux et chaud. Pour certaines régions à climat humide, les performances du système seraient trop faibles pour qu’il soit utilisé seul et un pré-déshumidificateur doit être incorporé pour améliorer ses performances pour une application plus large. Sa puissance de rafraîchissement varie en fonction de la région où il est utilisé. Comparé au système de rafraîchissement à compression mécanique conventionnel, en somme, le système de point de rosée a un potentiel nettement plus élevé pour économiser et réduire les factures d'énergieWith population growth and the rapid urbanization process that affects almost all urban centers in the world, the energy need for cooling spaces continue to increase, particularly in emerging countries. this research is oriented towards techniques relating to new methods of ecological cooling at lower cost. The study has shown that indirect dewpoint evaporative cooling systems are among the most promising. Their ability to use the evaporation of water to absorb heat in order to lower the air temperature without adding humidity is a principle of cooling that consumes a small amount of energy with smallest negative impact upon the environment. From our investigations, it was possible to verify that the studied system could achieve higher efficiencies than typical indirect evaporative systems at lower cost. Its efficiency depends largely on the geometry of the channels, the flow rate and temperature of the intake air, humidity and the ratio of secondary air, but less on the temperature of the inlet water. substrate feed. It was also concluded that the dew point system is suitable for most areas with a dry, mild and hot climate. For some areas with humid climates, the performance of the system would be too low for it to be used alone and a pre-dehumidifier should be incorporated to improve its performance for a wider application. Its cooling capacity varies depending on the region where it is used. Compared to the conventional mechanical compression cooling system, the dew point system has a significantly higher performance potential to reduce energy bills
2
Elzaidabi, Abdalla Ali Mohamed. "Low energy, wind catcher assisted indirect-evaporative cooling system for building applications". Thesis, University of Nottingham, 2009. http://eprints.nottingham.ac.uk/10703/.
Abstract (sommario):
Increased consciousness of the environmental problems has aroused people’s interest of renewable energy systems, especially the application of green features in buildings. The demand for air conditioning / cooling in domestic and non-domestic buildings is rising throughout the world; this increases the reliance on conventional fuels and the global warming effect from greenhouse gas emissions. Passive cooling and energy efficient design can substantially reduce reliance on fuel based heating and cooling. Passive and Hybrid Downdraught Cooling, in different forms, is now technically viable in many parts of the world. This has been established through a combination of research projects. In some hot arid regions, a major part of the energy consumed consists of air-conditioning requirements. Alternative methods, using passive cooling techniques, can assist in reducing the conventional energy consumption in buildings. Evaporative cooling, which can be tracked back several hundreds of years in ancient Egypt and Persia [1–3], is one of the most effective strategies, because of the enormous latent heat needed for evaporation of water. Green features are architectural features used to mitigate migration of various air-borne pollutants and transmission of air from outside to indoor environment in an advantageous way [9]. The reduction of fossil fuel consumption and the associated decrease in greenhouse gas emissions are vital to combat global warming and this can be accomplished, in part, by the use of natural ventilation. To assess the performance of several innovative cooling systems devices and to develop improved models for more established technology, quantitative measurement of output was necessary. This was achieved in this study by the development of simply constructed low energy cooling systems which were calibrated by the innovative use of wind and water as a source. These devices were found to be consistent and accurate in measuring the temperature and cooling load from a number of devices. There were some problems in the original evaporative units. Therefore, a number of modifications have to be made to enhance the systems performance. The novel Windcatcher – PEC cooling system was assessed and different cooling loads were achieved.
3
Duan, Zhiyin. "Investigation of a novel dew point indirect evaporative air conditioning system for buildings". Thesis, University of Nottingham, 2011. http://eprints.nottingham.ac.uk/12200/.
Abstract (sommario):
This study aims to improve the performance of existing indirect evaporative coolers. A new dew point indirect evaporative cooler with counter-current heat/mass exchanger was developed in this research by optimal design, material selection, numerical simulation, experimental investigations and economic, environmental, regional acceptance analysis. A new dew point heat/mass exchanger using a counter-current flow pattern was designed by numerical simulation in terms of material, structure, geometrical sizes and operating conditions. The numerical results indicate that under a typical cooling design condition, i.e., 35oC dry-bulb/24oC wet-bulb temperatures, the heat exchanger could achieve a wet-bulb effectiveness of approximately 1.4. The results of numerical simulation are consistent with some published test data. Based on the numeric results and the material selection determined from a set of related tests, a prototype dew point heat/mass exchanger and the associated air cooler was designed and constructed in laboratory. Testing was carried out to evaluate the performance of the experiment prototype. The results indicate that the wet-bulb effectiveness of the prototype ranged from 55% to 110% for all test conditions. The power consumption of the prototype ranged from 10 to 50 W with energy efficiency (or COP) rated from 3 to 12. It is also found that the water consumption of the prototype was very small which ranged from 0.2-1.3 litre/h. A comparison between the numerical and experimental results was carried out and the reasons for the discrepancy were analysed. This research also investigates the feasibility, economic and environmental potential of using a dew point cooler in buildings in Europe and China. From the related studies in this thesis, it is concluded that the dew point cooler can achieve a higher performance (in terms of effectiveness and energy efficiency) than the typical indirect evaporative coolers without adding too much cost. It is found that the effectiveness and energy efficiency of the heat/mass exchanger in the cooler are largely dependent upon channel geometries, the intake air velocity, temperature, humidity and the working-to-intake air ratio but less on the feed water temperature. To maximise effectiveness and energy efficiency, it is suggested that 1) the channel height and the length of exchanger should be set below 6 mm and 1-1.2 m respectively; 2) the intake channel air velocity should be controlled to 0.5-1 m/s; and 3) the working-to-intake air ratio should be adjusted to 0.4-0.5. It is also concluded that the dew point system is suitable for most regions with dry, mild and hot climate. It is, however, unsuitable for humid regions where the system is used as a stand-alone unit. Compared to the conventional mechanical compression cooling system, the dew point system has a significantly higher potential in saving energy bills and reducing carbon emission. A project to construct an 8 kW commercial dew point cooler is currently under development with the assistance of a Chinese company. By the optimisation of material, structure and geometries, the cooler is expected to achieve a cooling output of 8 kW at the inlet air of 38oC dry-bulb/ 21oC wet-bulb temperatures, with a wet-bulb effectiveness of 1.02 at 1530 m3/h of supply air flow and 1200 m3/h of discharge air flow, whereas the power input of the unit is about 450 W and the energy efficiency (or COP) at 18.5.
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Cheng, D. Christopher. "Energy savings for an air-to-air residential heat pump using indirect evaporative cooling". [Gainesville, Fla.] : University of Florida, 2006. http://purl.fcla.edu/fcla/etd/UFE0013403.
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Al-Koheji, Mohamed Y. "Application of porous ceramics and wind catchers for direct and indirect evaporative cooling in buildings". Thesis, University of Nottingham, 2003. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.289313.
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Lionello, Michele. "Modelling and control of cooling systems for data center applications". Doctoral thesis, Università degli studi di Padova, 2019. http://hdl.handle.net/11577/3424786.
Abstract (sommario):
Nowadays, the Data Center industry is playing a leading role in the world economic development and it is growing rapidly and constantly. Beside this, it has become more concerned with energy consumption and the associated environmental effects. Since about half of the total energy consumption in a typical Data Center is devoted to cooling the IT equipment, energy efficiency must be the primary focus in the design and management of the cooling infrastructure.
In this Thesis, we consider the problem of optimizing the operation of cooling systems in Data Centers. The main objective is that of maximizing the energy efficiency of the systems, while provisioning the required cooling demand. For this purpose, we propose a two-layer hierarchical control approach, where a supervisory high-level layer determines the optimal set-points for the local low-level controllers. The supervisory layer exploits an Extremum Seeking model-free optimization algorithm, which ensures flexibility and robustness against changes in the operating conditions. In particular, a Newton-like Phasor-based Extremum Seeking scheme is presented to improve the convergence properties and the robustness of the algorithm.
The proposed control architecture is tested in silico in optimizing the operation of an Indirect Evaporative Cooling system and a Liquid Immersion Cooling unit. Simulations are performed by exploiting First-Principle Data-Driven models of the considered systems and the results demonstrate the effectiveness of the proposed approach.
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Reddy, Sudheer Kumar V. "Development And Performance Evaluation Of An Indirect Evaporative Air Cooler". Thesis, 2011. https://etd.iisc.ac.in/handle/2005/2384.
Abstract (sommario):
Evaporative cooling is an alternative and efficient method of cooling in dry climates. When a liquid evaporates into the surrounding gas, the energy required for the change of phase produces a cooling effect. The wet bulb depression is the measure of potential for evaporative cooling. Greater the wet bulb depression greater is the cooling effect, and vice versa.
The residential desert cooler, apart from cooling the air increases the humidity of the air in the room by absorbing moisture from the water supplied to the cooler. This may result in an undesirable increase in humidity level. Allergies is an additional problem with direct evaporative coolers. Indirect evaporative cooling does not have these two drawbacks.
In the present work a small indirect evaporative cooler is developed with a cross flow heat exchanger and the performance of the cooler is evaluated under controlled environmental conditions. The results are compared with the results of an analytical model developed by assuming constant water film temperature on the external wall of the heat exchanger tube. The experimental results of the cooler show a satisfactory agreement with the analytical values. Design calculations are presented to show the performance characteristics of indirect evaporative coolers under different temperature and humidity conditions of the ambient. It has been shown that reducing the heat exchanger tube diameter to around 2 mm results in better cooling effect. Climatic conditions of different Indian cities are discussed with respect to the expected effectiveness of indirect evaporative coolers.
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Reddy, Sudheer Kumar V. "Development And Performance Evaluation Of An Indirect Evaporative Air Cooler". Thesis, 2011. http://etd.iisc.ernet.in/handle/2005/2384.
Abstract (sommario):
Evaporative cooling is an alternative and efficient method of cooling in dry climates. When a liquid evaporates into the surrounding gas, the energy required for the change of phase produces a cooling effect. The wet bulb depression is the measure of potential for evaporative cooling. Greater the wet bulb depression greater is the cooling effect, and vice versa.
The residential desert cooler, apart from cooling the air increases the humidity of the air in the room by absorbing moisture from the water supplied to the cooler. This may result in an undesirable increase in humidity level. Allergies is an additional problem with direct evaporative coolers. Indirect evaporative cooling does not have these two drawbacks.
In the present work a small indirect evaporative cooler is developed with a cross flow heat exchanger and the performance of the cooler is evaluated under controlled environmental conditions. The results are compared with the results of an analytical model developed by assuming constant water film temperature on the external wall of the heat exchanger tube. The experimental results of the cooler show a satisfactory agreement with the analytical values. Design calculations are presented to show the performance characteristics of indirect evaporative coolers under different temperature and humidity conditions of the ambient. It has been shown that reducing the heat exchanger tube diameter to around 2 mm results in better cooling effect. Climatic conditions of different Indian cities are discussed with respect to the expected effectiveness of indirect evaporative coolers.
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Sousa, Hugo Neves de. "Estudo de um arrefecedor evaporativo indirecto de elevada eficiência". Master's thesis, 2010. http://hdl.handle.net/10216/63338.
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Sousa, Hugo Neves de. "Estudo de um arrefecedor evaporativo indirecto de elevada eficiência". Dissertação, 2010. http://hdl.handle.net/10216/63338.
Libri sul tema "Indirect Evaporation":
1
Lin, Jie, e Kian Jon Chua. Indirect Dew-Point Evaporative Cooling: Principles and Applications. Cham: Springer International Publishing, 2023. http://dx.doi.org/10.1007/978-3-031-30758-4.
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A comparison of Class A pan evaporation measurements with Penman and Tombesi-Lauciani indirect estimation methods =: Confronto tra l'evaporazione misurata da Classe A pan e i metodi per la stima indiretta secondo Penman e Tombesi-Lauciani. Roma: Istituto sperimentale per la nutrizione delle piante, 1988.
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Method of Test for Rating Indirect Evaporative Coolers (A S H R a E Standards, 143-2000). Amer Society of Heating, 2000.
Capitoli di libri sul tema "Indirect Evaporation":
1
Weill, A. "Indirect Measurements of Fluxes Using Doppler Sodar". In Land Surface Evaporation, 301–11. New York, NY: Springer New York, 1991. http://dx.doi.org/10.1007/978-1-4612-3032-8_18.
2
Watt, John R. "Experimental Indirect Cooling". In Evaporative Air Conditioning Handbook, 394–412. Boston, MA: Springer US, 1986. http://dx.doi.org/10.1007/978-1-4613-2259-7_23.
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Watt, John R. "Indirect Evaporative Cooling Systems". In Evaporative Air Conditioning Handbook, 331–47. Boston, MA: Springer US, 1986. http://dx.doi.org/10.1007/978-1-4613-2259-7_20.
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Watt, John R. "Other Modern Indirect Cooling". In Evaporative Air Conditioning Handbook, 367–93. Boston, MA: Springer US, 1986. http://dx.doi.org/10.1007/978-1-4613-2259-7_22.
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Watt, John R. "Modern Plate-Type Indirect Cooling". In Evaporative Air Conditioning Handbook, 348–66. Boston, MA: Springer US, 1986. http://dx.doi.org/10.1007/978-1-4613-2259-7_21.
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Almusaed, Amjad. "Cooling by Indirect Evaporative Systems". In Biophilic and Bioclimatic Architecture, 363–66. London: Springer London, 2010. http://dx.doi.org/10.1007/978-1-84996-534-7_31.
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Lin, Jie, e Kian Jon Chua. "Working Principles of Evaporative Cooling". In Indirect Dew-Point Evaporative Cooling: Principles and Applications, 15–24. Cham: Springer International Publishing, 2023. http://dx.doi.org/10.1007/978-3-031-30758-4_2.
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Lin, Jie, e Kian Jon Chua. "Modeling of Dew-Point Evaporative Coolers". In Indirect Dew-Point Evaporative Cooling: Principles and Applications, 53–77. Cham: Springer International Publishing, 2023. http://dx.doi.org/10.1007/978-3-031-30758-4_4.
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Lin, Jie, e Kian Jon Chua. "Advanced Dew-Point Evaporative Cooling Systems". In Indirect Dew-Point Evaporative Cooling: Principles and Applications, 107–16. Cham: Springer International Publishing, 2023. http://dx.doi.org/10.1007/978-3-031-30758-4_6.
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Lin, Jie, e Kian Jon Chua. "Engineering of Dew-Point Evaporative Coolers". In Indirect Dew-Point Evaporative Cooling: Principles and Applications, 25–52. Cham: Springer International Publishing, 2023. http://dx.doi.org/10.1007/978-3-031-30758-4_3.
Atti di convegni sul tema "Indirect Evaporation":
1
Dartnall, W. John, Alex Revel e Vasilios Giotis. "Air-Conditioning Employing Indirect Evaporative Cooling Can Be Shown to Derive Its Energy From the Solar Source". In ASME 2009 International Mechanical Engineering Congress and Exposition. ASMEDC, 2009. http://dx.doi.org/10.1115/imece2009-10928.
Abstract (sommario):
This paper explains how Indirect Evaporative Cooling (IEC) uses water as a refrigerant. This water refrigerant may be seen as part of the rain cycle, whereby the environment (not a heat pump) returns water as the refrigerant to the system after re-condensing it. Since the rain cycle is largely driven by the solar source, so then is IEC. Indirect Evaporative Cooling (IEC) may be efficiently produced by wetting the room exhaust stream plates of an air-to-air heat exchanger so that water evaporation caused by the cool, relatively dry exhaust air effectively cools the incoming ventilation air stream as it passes through the other (supply) side of the heat exchanger. In practice, very high Coefficients of Performance (COP’s) have been recorded with IEC’s operating in hot, dry climates. These systems perform with low energy consumption requiring energy only to power fans and small water pumps. Surprisingly, a humid climate also yields a very high COP.
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Zadpoor, Amir Abbas, e Ali Asadi Nikooyan. "Development of an Improved Desiccant-Based Evaporative Cooling System for Gas Turbines". In ASME Turbo Expo 2008: Power for Land, Sea, and Air. ASMEDC, 2008. http://dx.doi.org/10.1115/gt2008-50258.
Abstract (sommario):
The evaporative inlet cooling systems used for inlet cooling of gas turbines during hot summers do not work well in humid areas. However, desiccant wheels can be used to dehumidify the air before passing it trough the evaporative cooler. Since the desiccant wheels work adiabatically, the resulting air is hotter than the air introduced to the wheel and an evaporative cooling system is used to cool down the dehumidified air. Combined direct and indirect evaporative coolers have been already used to investigate the effects of dehumidification on the effectiveness of the evaporation cooling systems. It is shown that a single desiccant wheel does not offer much higher effectiveness compared to the multiple-stage evaporative systems. In this paper, an improved version of the desiccant inlet cooling system is presented. Additional dehumidification and indirect evaporative cooling stages are added to increase the effectiveness of the inlet cooling. A typical gas turbine cycle along with an industrial gas turbine with actual performance curves are used to simulate the thermal cycle in presence of the different inlet cooling systems. The simulations are carried out for three different climatic conditions. The improved and original desiccant-based systems are compared and it is shown that the added stages substantially improve the effectiveness of the desiccant-based inlet cooling.
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Tejada, Francisco, Bert Bras e Tina Guldberg. "Direct and Indirect Water Consumption in Vehicle Manufacturing". In ASME 2012 International Design Engineering Technical Conferences and Computers and Information in Engineering Conference. American Society of Mechanical Engineers, 2012. http://dx.doi.org/10.1115/detc2012-71307.
Abstract (sommario):
There is a growing need to include the availability of water sources as a design criterion because future forecasts suggest that water demands will increase significantly while freshwater resources are being depleted. In this paper, we focus on the amounts of water that are consumed in automotive vehicle manufacturing and life-cycle processes. Although water use is typically metered at the factory level, water consumption (i.e., water lost through evaporation and/or incorporation into a material, part, and/or product) is much harder to quantify. In this paper, we will discuss the amount of water consumed directly in vehicle manufacturing and the vehicle life cycle processes. This “direct” water consumption can be directly traced to the vehicle manufacturing analogously to direct labor. It will also be shown that indirect processes, specifically, electricity production and consumption also counts for a significant amount of water consumption. Reduction of electricity consumption, in particular from thermo-electric power plants, can lead to substantial water consumption reductions, and thus win-win situations. The impact of water consumption varies by region and locality, and the impact of water saving technologies in production may be negated by increased use of electricity in water scarce regions.
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Taheri, Mohammad Hasan, e Hamid Reza Goshayeshi. "Numerical Simulation of Flows With Evaporation". In ASME 2012 International Mechanical Engineering Congress and Exposition. American Society of Mechanical Engineers, 2012. http://dx.doi.org/10.1115/imece2012-85425.
Abstract (sommario):
Multiphase flows are usually accompanied by thermodynamic effects. These effects are associated with gas-liquid phase transition which can occur in a single fluid system as well as in systems comprising more than one species. Appearance of the transition in a system has substantial thermal and mechanical consequences, such as transfer of mass, momentum as well as energy and change in the temperature field. Flows coupled with phase change occur abundantly in nature. They are responsible for atmospheric phenomena such as cloud formation, absorption of gases (including green house ones) by sea water and many other phenomena of a global or local scale, which influences everyday life. Multiphase flows are also often present in many industrial applications in which their physical features are advantageous or disadvantageous. Installations in the oil production industry and energy production plants are examples of installations in which multi-phase flows with phase transition appear. Phase transition is a desired phenomenon in vapor generation systems such as power plant boilers or water cooled nuclear reactors; as well as indirect or direct contact vapor condensers or mass transfer equipment used e.g. for humidification. Phase transition can also be an undesired phenomenon. It occurs in pumps and on ship propellers where because the pressure decreases considerably at the suction side of the impeller or propeller blade, cavitation appears. This sort of transition can cause oscillations and may threaten the structural integrity of the impeller or propeller. Two driving mechanisms for phase transition inside a fluid can be distinguished. The first is variation of the pressure leading to cavitation, whereas the second one is heat transfer (temperature) resulting in boiling and evaporation/condensation. Over the past decades researchers put much effort in the development of algorithms capable of numerically simulate multiphase flows with phase transition. The present study concerns the development of a method for the prediction of multiphase flow with temperature-driven phase transition for which the geometry of the gas-liquid interface is not known in advance. A single substance is considered consisting of incompressible phases. The gas-liquid interface in multiphase flows, with or without phase transition, involves a discontinuity in the physical properties of the flow at the interface. This leads to difficulties in preserving convergence in numerical algorithms for predicting single phase flows. The investigation of mixed convection heat and mass transfer on a vertical plate with film evaporation has been numerically examined. Results were obtained for mixed convection driven by combined thermal and mass buoyancy forces. The numerical results, including velocity, temperature and concentration distributions, Nusselt number as well as Sherwood number and evaporation rate are presented. The results show that below a certain temperature, water evaporation rate decreases as the humidity of air increases and above it this relation reverses. This temperature is named “inversion point temperature”. A numerical model using the finite difference method was developed and tested systematically.
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Ninković, Dimitrije, Uroš Milovančević, Milena Otović e Vladimir Černicin. "Comparative Analysis of Electric Energy Consumption of Cascade System R134a/CO2 with Single Stage R404a and Two-Stage CO2 Installation". In 50th International HVAC&R Congress and Exhibition. SMEITS, 2020. http://dx.doi.org/10.24094/kghk.019.50.1.287.
Abstract (sommario):
The paper analyzes electric energy consumption of three different refrigeration installations: cascade refrigeration system with R134a in the high temperature circuit and CO2 in the low temperature circuit, single stage refrigeration system operating with R404A and two-stage transcritical CO2 system. The indirect impact of the refrigeration system on global warming through electric energy consumption was examined. Thermodynamic cycles of these installations have been described and models have been developed to analyze the electric energy consumption required to drive the compressor as the largest consumer, for the cooling capacity of the evaporator 5,7 kW at evaporation temperature -30 °C for meteorological 2017, in the city of Belgrade. As a basis for comparative analysis, the existing cascade refrigeration system, which is located in the Laboratory for Thermal Science at the Faculty of Mechanical Engineering in Belgrade, was selected.
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Zyromski, Andrzej, Marcin Wdowikowski e Bartosz Kazmierczak. "Estimation of evapotranspiration empirical coefficients of scots pine (Pinus sylvestris) under climate change conditions". In 22nd International Scientific Conference Engineering for Rural Development. Latvia University of Life Sciences and Technologies, Faculty of Engineering, 2023. http://dx.doi.org/10.22616/erdev.2023.22.tf200.
Abstract (sommario):
The aim of this study was to assess the feasibility of estimating the evapotranspiration of Scots pine (Pinus silvestris) using an indirect method. The field experiment was conducted at the Agro and Hydrometeorology Observatory of the Faculty of Environmental Engineering and Geodesy of the Wrocław University of Life Sciences in Poland from 1 May to 31 October from 2016 to 2019. The experiment covered the period from the 6th to the 9th year of cultivation of Scots pine (Pinus silvestris) on arable land. Evapotranspiration of Scots pine (ETR) was measured in soil evaporometers of 0.3 m2 and 0.7 m soil monolith thickness, with a daily time step, in triplicate. In order to avoid the oasis effect, the soil evaporometers were installed so that the measured trees grew in a compact enclave, as they do under natural conditions. In parallel, the actual evaporation values from the free water surface were measured directly with the EWP 992 evaporometer, and the daily indicator evaporation values were calculated using the FAO Penman-Monteith formula. In the next step, using evaporation measurements from the EWP 992 evaporometer and determined with the FAO Penman-Monteith formula, decadal and monthly empirical coefficients were determined to estimate the evapotranspiration of Scots pine. Evaluation of the weather conditions in the individual years of the experiment was also carried out, relating it to the normative multi-year period 1981–2010.
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Zhang, Yan, Tao Mei, Deyi Kong, Chengmei Zhang, Yongchun Tao e Shengjun Hu. "Principle and Experimental Study of a MEMS Explosive Particle Detector". In ASME 2003 International Mechanical Engineering Congress and Exposition. ASMEDC, 2003. http://dx.doi.org/10.1115/imece2003-41236.
Abstract (sommario):
A new explosive particle detection with MEMS is presented in this paper, which utilize the properties of explosive particles. The principle of the detector is described firstly: every explosive has unique melting and evaporation point, when single explosive particle on the sensor surface melts and absorbs heat from it, the temperature change of the sensor will occurs. Unlike other indirect detecting method, a step heating method was proposed to control the working state of the sensor. The method had the advantages of easy implementation, active controlling and high selectivity: Firstly, the voltage will make the temperature of the sensor a little lower than the melting point of explosive, and the fusion of the explosive will not occur yet; With the voltage begin to increase again, the temperature of the sensor will also increase up to the melting point and produce a respond graph called base graph. The same voltage pulse was sent through the sensor before and after putting the explosive particles on the sensor surface. Absorption of heat from it during melting and evaporation causes its temperature changing and the shift on the respond graph is different from the former. Furthermore, experiments have been performed to confirm the feasibility to measure the temperature directly, and the graph is presented to show the difference between the changing with TNT sample existing or not, the resistance changing is apparent in graph when the temperature increase close to the melting point of TNT.
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Terček, Jure. "Physics of Respiratory Pathogen Transmission Through Droplets and Aerosol". In Socratic Lectures 8. University of Lubljana Press, 2023. http://dx.doi.org/10.55295/psl.2023.i20.
Abstract (sommario):
Recent epidemic of the COVID-19 (CoronaVirus Disease-19), caused by SARS-CoV-2 virus exposed great gaps in the understanding of respiratory transmitted diseases in many public health institutions. Traditionally, respiratory pathogens are believed to spread through: direct physical contact (like spray of droplets onto mucous membrane), indirect contact with contaminated surfaces (known as “fomites”) and inhalation of aerosols. Public health has relied on a strict split between heavy falling droplets and lighter airlingering aerosols. In this review we take a look at this distinction, comment on potential problems of its definition and examine a few basic physical phenomena affecting airborne droplet behaviour. We conclude that droplets smaller than 10 µm tend to linger in the air for extended periods of time and that air circulation has a big impact on the presence of pathogen-carrying particles in the air, which may help craft better public health policy. Keywords: Droplets; Aerosols; Transmission; Respiratory disease; Droplet sedimentation; Droplet evaporation; Public health
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Lin, Jen Fin, e Hsiao Yeh Chu. "Analysis of the Be´nard Cell-Like Worn Surface Type Occurred During Oil-Lubricated Sliding Contact". In ASME/STLE 2009 International Joint Tribology Conference. ASMEDC, 2009. http://dx.doi.org/10.1115/ijtc2009-15130.
Abstract (sommario):
Scuffing wear is usually used as an important indication of the initiation of lubrication failure. Components with scuffing wear should be readily replaced in order to avoid severe wear. This paper observed the change of surface structure in the scuffed area of the worn surface of oil-lubricated vanes-on-ring specimens from a microscopic and nano-scale observation and material characterization. There existed a kind of Be´nard cell-like special surface shape found from the observation of the TEM image of the scuffed surface. In order to see whether there was very hot surface temperature to produce Benard cell, structure of the surface ferrous material was used as an indirect evidence of high temperature. It showed that the temperature in the scuffed area suffered a very high temperature which was over 800°C from the TEM Result. It showed that very strong fluid convection or even evaporation may occur inside the scuffed surface. The material strength of the scuffed surface would be much lower due to this high temperature. The oil pressure of that high temperature area was also very high. These factors made it possible to form the Be´nard cell structure in microscale.
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Dakshinamurthy, Hemanth N., Ashwin Siddarth, Abhishek Guhe, Rajesh Kasukurthy, James Hoverson e Dereje Agonafer. "Accelerated Degradation Testing of Rigid Wet Cooling Media to Analyse the Impact of Calcium Scaling". In ASME 2018 International Mechanical Engineering Congress and Exposition. American Society of Mechanical Engineers, 2018. http://dx.doi.org/10.1115/imece2018-88508.
Abstract (sommario):
Rigid wet cooling media is a key component of direct and indirect evaporative cooling systems. Evaporation is the process of a substance in a liquid state changing to a gaseous state. When water evaporates only water molecules get evaporated and the other chemicals in the water are left behind on the surface as residue. Many studies have been conducted on how the change in air flow velocity, media depth, porosity and water distribution affect performance of the cooling system. The operational efficiency of the cooling media varies over its life cycle and depends primarily on temperature and speed of inlet air, water distribution system, type of pad and dimension of the pad. Although evaporative cooling when implemented with air-side economization enables efficiency gains, a trade-off between the system maintenance and its operational efficiency exists. In this study, the primary objective is to determine how calcium scale affects the overall performance of the cooling pad and the water system. Areas of the pad that are not wetted effectively allow air to pass through without being cooled and the edges between wetted and dry surface establish sites for scale formation. An Accelerated Degradation Testing (ADT) by rapid wetting and drying on the media pads at elevated levels of calcium is designed and conducted on the cellulose wet cooling media pad. This research focuses on monitoring the degradation that occurs over its usage and establish a key maintenance parameter for water used in media pad. As a novel study, preliminary tests were mandatory because there were no established standards for media pad degradation testing. Sump water conductivity is identified as the key maintenance parameter for monitoring sump replenishing and draining cycles which will result in reduced water usage. The average water conductivity in the sump during wetting cycles increases monotonically when ADT was performed on a new media pad. An empirical relationship between sump water conductivity and number of wetting cycles is proposed. This information will be very helpful for the manufacturers to guide their customers for maintenance of the media pad and sump water drain cycles.