Journal articles on the topic 'Indirect Evaporation'
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1
Cichoń, Aleksandra, Anna Pacak, Demis Pandelidis, and 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:
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, and Viliam Novák. "THEORY OF EVAPOTRANSPIRATION: 2. Soil and intercepted water evaporation." Journal of Hydrology and Hydromechanics 59, no. 2 (June 1, 2011): 73–84. http://dx.doi.org/10.2478/v10098-011-0006-8.
Abstract:
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.
3
Asemi, Hamidreza, Rahim Zahedi, and Sareh Daneshgar. "Theoretical analysis of the performance and optimization of indirect flat evaporative coolers." Future Energy 2, no. 1 (November 15, 2022): 9–14. http://dx.doi.org/10.55670/fpll.fuen.2.1.2.
Abstract:
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.
4
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, no. 04 (December 2015): 1550026. http://dx.doi.org/10.1142/s2010132515500261.
Abstract:
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.
5
CHOWDHURY, A., H. P. DAS, and S. D. GAIKWAD. "Determination of relative contribution of different meteorological elements on evaporation." MAUSAM 50, no. 4 (December 17, 2021): 365–74. http://dx.doi.org/10.54302/mausam.v50i4.1949.
Abstract:
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.
6
Dalaf, Adham Ahmed, Maki Haj Zidan, and Aadel A. Al-Kumait. "Improving the Behavior of Indirect Evaporative Cooler*." Journal of Advanced Sciences and Engineering Technologies 1, no. 3 (December 26, 2021): 11–17. http://dx.doi.org/10.32441/jaset.01.03.02.
Abstract:
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
7
Shevnina, Elena, Miguel Potes, Timo Vihma, Tuomas Naakka, Pankaj Ramji Dhote, and Praveen Kumar Thakur. "Evaporation over a glacial lake in Antarctica." Cryosphere 16, no. 8 (August 2, 2022): 3101–21. http://dx.doi.org/10.5194/tc-16-3101-2022.
Abstract:
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.
8
Sun, Tiezhu, Xiaojun Huang, Caihang Liang, Riming Liu, and Xiang Huang. "Prediction and Analysis of Dew Point Indirect Evaporative Cooler Performance by Artificial Neural Network Method." Energies 15, no. 13 (June 25, 2022): 4673. http://dx.doi.org/10.3390/en15134673.
Abstract:
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.
9
Jayakody, Harith, Raya Al-Dadah, and Saad Mahmoud. "Cryogenic Energy for Indirect Freeze Desalination—Numerical and Experimental Investigation." Processes 8, no. 1 (December 21, 2019): 19. http://dx.doi.org/10.3390/pr8010019.
Abstract:
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.
10
Hashim, Rasha, Salman Hammdi, and Adel Eidan. "Evaporative Cooling: A Review of its Types and Modeling." Basrah journal for engineering science 22, no. 1 (April 24, 2022): 36–47. http://dx.doi.org/10.33971/bjes.22.1.5.
Abstract:
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.
11
Chernyshev, B., L. Jean-Korotkova, Y. Gurov, T. Leonova, S. Lapushkin, R. Pritula, and T. Shchurenkova. "Charged Particles Evaporation in the Stopped Pion Absorption Reactions." KnE Energy 3, no. 1 (April 9, 2018): 41. http://dx.doi.org/10.18502/ken.v3i1.1720.
Abstract:
In the present work we have analyzed evaporation spectra and yields of p,d,t formed in the reaction of stopped pion absorption. It is shown that the values of equilibrium temperature obtained through the usage of proposed model are in agreement with the values obtained in various other experiments. We also discuss the A-dependences of the evaporation yields and consider possible contributions of the “indirect” evaporation processes.
12
Rezaee, Vahid, and Arash Houshmand. "Feasibility Study Of Maisotsenko Indirect Evaporative Air Cooling Cycle In Iran." GeoScience Engineering 61, no. 2 (June 1, 2015): 23–36. http://dx.doi.org/10.1515/gse-2015-0015.
Abstract:
Abstract This paper presents energy and exergy analysis of air cooling cycle based on novel Maisotsenko indirect evaporative cooling cycle. Maisotsenko cycle (M-cycle) provides desired cooling condition above the dew point and below the wet bulb temperature. In this study, based on average annual temperature, The Iran area is segmented into eleven climates. In energy analysis, wet-bulb and dew point effectiveness, cooling capacity rate and in exergy analysis, exergy input rate, exergy destruction rate, exergy loss, exergy efficiency, exergetic COP and entropy generation rate for Iran's weather conditions in the indicated climates are calculated. Moreover, a feasibility study based on water evaporation rate and Maisotsenko cycle was presented. Energy and exergy analysis results show that the fifth, sixth, seventh and eighth climates are quite compatible and Rasht, Sari, Ramsar and Ardabile cities are irreconcilable with the Maisotsenko cycle.
13
Gorbachev, M., and V. Terekhov. "A comparative analysis of schemes of indirect evaporation type apparatuses." Journal of Physics: Conference Series 2057, no. 1 (October 1, 2021): 012130. http://dx.doi.org/10.1088/1742-6596/2057/1/012130.
Abstract:
Abstract In this paper, a comparative analysis of schemes of heat and mass transfer devices of indirect evaporation type is carried out. These devices are a family of plane-parallel channels, in one of which the evaporation of water film takes place. Mathematical modeling of heat and mass transfer devices is based on solving a system of differential equations that represent the heat balance equations for each of the channels. Numerical studies are carried out in a wide range of input parameters: temperature t0 = 15÷50°C, relative air humidity ϕ0 = 20÷100%, and Reynolds number Re = 50÷1500. The assumed geometric dimensions of the channels are height H = 6 mm and length L 50H. The calculations are carried out at atmospheric pressure.
14
Pawłowski, Mateusz, Jerzy Gagan, and Dariusz Butrymowicz. "Assessment of Efficiency of Heat Transportation in Indirect Propane Refrigeration System Equipped with Carbon Dioxide Circulation Loop." Sustainability 14, no. 16 (August 22, 2022): 10422. http://dx.doi.org/10.3390/su141610422.
Abstract:
Recent research on indirect cooling systems using natural refrigerants has become increasingly common. One such solution is the gravity-induced circulation loop. The paper provides model considerations of the configuration of an indirect propane refrigeration system equipped with a circulation loop using carbon dioxide as a heat transfer fluid. Close attention has been paid to the analytical modelling of the carbon dioxide circulation loop operation. The model was formulated to determine the optimum height of the liquid downcomer based on the determination of flow resistance and heat transfer rate in evaporation and condensation processes. A validation of the proposed analytical model against the available literature on two-phase flow structure predictions and thermal performance predictions was performed. The effect of the change in the refrigeration capacity of the system on the coefficient of performance COP of the entire indirect system was analysed for the first time. The analysis was performed for three different carbon dioxide evaporation temperatures for the system’s refrigeration capacity, ranging from 0.5 to 10 kW. It has been proven that the system efficiency increases by up to 23% with an increase in the refrigeration capacity of the system. An increase in evaporation temperature in the circulation loop from −20 °C to 0 °C improves the COP of the entire indirect refrigeration system by approximately 50%. The above findings indicate that indirect cooling systems using naturally circulated CO2 as a heat transfer fluid should be designed for operation at maximum refrigeration capacity.
15
Havlík, Jan, Tomáš Dlouhý, and Michel Sabatini. "THE EFFECT OF THE FILLING RATIO ON THE OPERATING CHARACTERISTICS OF AN INDIRECT DRUM DRYER." Acta Polytechnica 60, no. 1 (March 2, 2020): 49–55. http://dx.doi.org/10.14311/ap.2020.60.0049.
Abstract:
This article investigates the effect of the filling ratio of the indirect rotary dryers on their operating characteristics. For moist biomass drying before combustion, the use of indirect drum dryers heated by a low pressure steam has proven to be highly suitable. Regarding the design of new dryers, it is necessary to experimentally verify the operating characteristics for specific materials and drying conditions. For this purpose, a set of experiments on a steam heated rotary drum dryer were carried out with green wood chips containing 60 to 66 wt% of moisture. The following operational characteristics of the dryer were experimentally determined: drying curves describing the process, square and volumetric evaporation capacities and drying heat consumptions. Based on the experimental results, the effect of various drum filling by dried material on the mentioned operating characteristics was analysed. On the one hand, higher drum filling ratio increases the drying time, on the other hand, the evaporation capacity also increases, while the specific energy consumption does not significantly alter. The maximum value of the evaporation capacity was reached when the drum was filled to 20 wt%. When the filling ratio was increased to 25 wt%, the evaporation capacity experienced almost no change.
16
Caruana, Roberta, Stefano De Antonellis, Luca Marocco, and Manfredo Guilizzoni. "Modeling of Indirect Evaporative Cooling Systems: A Review." Fluids 8, no. 11 (November 18, 2023): 303. http://dx.doi.org/10.3390/fluids8110303.
Abstract:
Air-to-air indirect evaporative cooling (IEC) systems are particular heat exchangers that use the latent heat of evaporation of water to cool down an air stream, without increasing its specific humidity, thus guaranteeing adequate thermohygrometric conditions in the refrigerated environment with low energy consumption. Dew-point indirect evaporative cooling (DIEC) systems are based on the IEC technology, but they recirculate a part of the air taken from the room to be refrigerated, in order to possibly achieve a lower air temperature. IEC and DIEC systems are becoming increasingly common these years, as they can ensure a good efficiency, minimizing the environmental impact of the air-conditioning system. Consequently, it has been necessary to develop models, both analytical and numerical, to quickly and accurately design this type of system and to predict their performance. This paper presents a review of the analytical and numerical models developed specifically for IEC and DIEC systems, highlighting their method, main innovations and advantages, and possible limitations. From this analysis, it emerged that analytical models have been developed since the late 1990s and only few of them are suitable for DIEC heat exchangers, while numerical models for both IEC and DIEC systems are gaining popularity in recent years. Almost all the analyzed models have been validated by comparison with numerical and/or experimental data, showing a maximum discrepancy within 10% in the majority of the cases. However, the validations were performed for a few specific cases, so in real applications it might be difficult to associate the model boundary conditions and the heat exchangers operating conditions, such as nozzles orientations, plates materials, water flow rates, and configurations. Another common limitation concerns the modeling of some properties, as wettability factor and air density, which might affect the accuracy of the results.
17
Metzger, Jutta, Manuela Nied, Ulrich Corsmeier, Jörg Kleffmann, and Christoph Kottmeier. "Dead Sea evaporation by eddy covariance measurements vs. aerodynamic, energy budget, Priestley–Taylor, and Penman estimates." Hydrology and Earth System Sciences 22, no. 2 (February 9, 2018): 1135–55. http://dx.doi.org/10.5194/hess-22-1135-2018.
Abstract:
Abstract. The Dead Sea is a terminal lake, located in an arid environment. Evaporation is the key component of the Dead Sea water budget and accounts for the main loss of water. So far, lake evaporation has been determined by indirect methods only and not measured directly. Consequently, the governing factors of evaporation are unknown. For the first time, long-term eddy covariance measurements were performed at the western Dead Sea shore for a period of 1 year by implementing a new concept for onshore lake evaporation measurements. To account for lake evaporation during offshore wind conditions, a robust and reliable multiple regression model was developed using the identified governing factors wind velocity and water vapour pressure deficit. An overall regression coefficient of 0.8 is achieved. The measurements show that the diurnal evaporation cycle is governed by three local wind systems: a lake breeze during daytime, strong downslope winds in the evening, and strong northerly along-valley flows during the night. After sunset, the strong winds cause half-hourly evaporation rates which are up to 100 % higher than during daytime. The median daily evaporation is 4.3 mm d−1 in July and 1.1 mm d−1 in December. The annual evaporation of the water surface at the measurement location was 994±88 mm a−1 from March 2014 until March 2015. Furthermore, the performance of indirect evaporation approaches was tested and compared to the measurements. The aerodynamic approach is applicable for sub-daily and multi-day calculations and attains correlation coefficients between 0.85 and 0.99. For the application of the Bowen ratio energy budget method and the Priestley–Taylor method, measurements of the heat storage term are inevitable on timescales up to 1 month. Otherwise strong seasonal biases occur. The Penman equation was adapted to calculate realistic evaporation, by using an empirically gained linear function for the heat storage term, achieving correlation coefficients between 0.92 and 0.97. In summary, this study introduces a new approach to measure lake evaporation with a station located at the shoreline, which is also transferable to other lakes. It provides the first directly measured Dead Sea evaporation rates as well as applicable methods for evaporation calculation. The first one enables us to further close the Dead Sea water budget, and the latter one enables us to facilitate water management in the region.
18
Pettijohn, J. Cory, and Guido D. Salvucci. "A New Two-Dimensional Physical Basis for the Complementary Relation between Terrestrial and Pan Evaporation." Journal of Hydrometeorology 10, no. 2 (April 1, 2009): 565–74. http://dx.doi.org/10.1175/2008jhm1026.1.
Abstract:
Abstract Archived global measurements of water loss from evaporation pans constitute an important indirect measure of evaporative flux. Historical data from evaporation pans shows a decreasing trend over the last half century, but the relationship between pan evaporation and moisture-limited terrestrial evaporation is complex, leading to ambiguities in the interpretation of these data. Under energy-limited conditions, pan evaporation Epan and moisture-limited terrestrial evaporation E increase or decrease together, whereas in moisture-limited conditions these fluxes form a complementary relation (CR) in which increases in one rate accompany decreases in the other rate. This has led to debate about the meaning of the observed trends in the context of changing climate. Here a two-dimensional numerical model of a wet pan in a drying landscape is used to demonstrate that, over a wide range of realistic atmospheric and surface conditions, the influence that changes in E have on Epan 1) are complementary and linear, 2) do not depend upon surface wind speed, and 3) are strikingly asymmetrical, in that a unit decrease in E causes approximately a fivefold increase in Epan, as found in a recent analysis by Kahler and Brutsaert of daily evaporation from U.S. grasslands. Previous attempts to explain the CR have been based on one-dimensional diffusion and energy balance arguments, leading to analytic solutions based on Penman-type bulk difference equations. However, without acknowledging the spatially complex humidity and temperature fields around the pan and, specifically, how these fields change as the contrast between the wet pan and the drying land surface increases, such integrated bulk difference equations are a priori incomplete (they ignore important divergence terms), and thus these explanations must be considered physically incomplete. Results of this study improve the theoretical foundation of the CR, thus increasing the reliability with which it can be applied to estimate water balance and to understand the pan evaporation record of climate change.
19
Gorbachev, Maksim V., and Viktor I. Terekhov. "Comparative analysis of heat and mass transfer apparatus schemes for indirect-evaporative air cooling." Proceedings of the Russian higher school Academy of sciences, no. 4 (December 27, 2022): 18–28. http://dx.doi.org/10.17212/1727-2769-2022-4-18-28.
Abstract:
In this paper, a comparative analysis of schemes of heat and mass transfer devices of indirect evaporation type is carried out. These devices are a family of plane-parallel channels, in one of which the evaporation of water film takes place. Mathematical modeling of heat and mass transfer devices is based on solving a system of differential equations that represent the heat balance equations for each of the channels. Numerical studies are carried out in a wide range of input parameters: temperature from 15 to 50 °С, relative air humidity from 20 to 100 %, and Reynolds number 50…1500. The calculations are carried out at atmospheric.
20
Du, Ying, Lujun Li, Xiaojun Song, and Fei Wang. "A Study on Mechanism of Evaporation Reduction of Desulfurization Wastewater in Air Cooling Tower." Journal of Physics: Conference Series 2694, no. 1 (January 1, 2024): 012002. http://dx.doi.org/10.1088/1742-6596/2694/1/012002.
Abstract:
Abstract It’s a new technology for the concentration and reduction of desulfurization wastewater by the indirect air cooling tower. In this paper, indoor experiments are conducted to explore the evaporation characteristics of the evaporation tower and the evaporation law of desulfurization wastewater in the filler and analyze the factors affecting the evaporation characteristics, and a power plant adopting this technology is tested to verify the conclusion of the indoor experiments. The results show that the evaporation rate of the evaporation tower is positively correlated with the cross-sectional wind speed, water spray density, packing height and other parameters, and the influence of the interrupted wind speed on the evaporation rate is the most significant. The difference of vapor pressure has a positive linear relationship with that of mass fraction of the air in inlet and outlet, and the results of model test conform to those of actual one basically. On the condition of ventilation rate of 817.56m3/s, the evaporation efficiency of a mechanical ventilation cooling tower with a drenching area of about 400m2 can reach 16.2-18.4t/h, which basically meets the engineering needs of desulfurization wastewater concentration and reduction in millions of thermal power plants.
21
Nowak, Bernard, and Zbigniew Kuczera. "Heat Power Determination of Dv-290 Refrigerator’s Evaporator on the Basis of Thermodynamic Parameters of Inlet Air / Określenie Mocy Cieplnej Parownika Chłodziarki Dv-290 Na Podstawie Parametrów Termodynamicznych Powietrza Wlotowego." Archives of Mining Sciences 57, no. 4 (December 1, 2012): 911–20. http://dx.doi.org/10.2478/v10267-012-0060-z.
Abstract:
Abstract The present paper introduces a method for calculating the thermal power of DV-290 mining air cooler’s evaporator. The power usually differs from the nominal power given by the manufacturer. The thermodynamic parameters of cooled air are not obtained as a result of in situ measurements, but in indirect manner that is by determining the evaporation and condensation’s pressure values of R407C refrigerant. The pressure dependencies formulated as a function of air enthalpy at the evaporator’s inlet were obtained using calculations of a computer program which solves the system of equations describing heat and mass transfer in the refrigerator’s compressor on the basis of previous measurements of air performed before and after its cooling. The obtained dependencies are demonstrated in a graphical (fig. 2 and fig. 3) and analytical (the regression equations (19) and (20)) manner, the values of correlation coefficients are also presented. For the known evaporation and condensation pressure values of the refrigerant, and thus for its basic physical parameters the complete thermal power of the evaporator was determined, that is its: air cooling overt power, dehumidification occult power, temperature, relative humidity and specific humidity of air after its cooling. In addition, using the mentioned method, the capacity of DV-290 refrigerator’s evaporator is provided for the given thermodynamic parameters of air before cooling, along with air thermodynamic parameters after cooling.
22
Chen, Hai Feng, Jian Hua Zhu, Long Jie Chen, and Miao Gen Qian. "Preparation and Contrast of Transparent Conductive TiO2/Ag/ZnS Film by Magnetron Sputtering and Evaporation Coating Deposition." Applied Mechanics and Materials 117-119 (October 2011): 1152–55. http://dx.doi.org/10.4028/www.scientific.net/amm.117-119.1152.
Abstract:
In this paper, TiO2/Ag/TiO2 and TiO2/Ag/ZnS films were prepared by evaporation coating (EC) and magnetron sputtering (MS). To test the resistance and light transmission rate to characterize the coating effect, both the size of indirect resistance that the relative thickness of the situation. By comparing the single magnetron sputtering and evaporation coating fabricated by the two transparent conductive oxide films (TCO) material conductivity and light transmission properties, determine a reasonable process. Firstly, the first layer is TiO2 film by magnetron sputtering, and then coating Ag film and ZnS film plated by evaporation, the final form of TiO2/Ag/ZnS film, which haSubscript textd much higher transmittance than TiO2/Ag/TiO2 at the same resistancSubscript texte.
23
Khrystian, Ye V., and I. V. Tytarenko. "JUSTIFICATION OF THE CHOICE OF AIR CONDITIONING SYSTEM FOR LOCOMOTIVES CAB." Science and Transport Progress, no. 18 (October 25, 2007): 25–28. http://dx.doi.org/10.15802/stp2007/17432.
Abstract:
The existing systems of an air conditioning by mobile machines are considered, the analysis of the strengths and weaknesses is performed. The improved conditioning system for a locomotive cabin is proposed on the basis of regenerative indirect evaporation cooling.
24
Шацкий, Vladimir Shatskiy, Гулевский, and Vyacheslav Gulevskiy. "Modeling of work of plate water evaporation coolers of indirect operation principle." Forestry Engineering Journal 3, no. 4 (January 21, 2014): 160–66. http://dx.doi.org/10.12737/2199.
Abstract:
More complex mathematical model is proposed which is a system of partial differential equations of elliptic and parabolic type with the corresponding initial and boundary conditions, which are not involved in the heat transfer coefficients, the deter-mination of the numerical values of which is very difficult. For its implementation diffe-rence analogue of the proposed model was built with Nx steps along the length of the channel, Ny steps along the section of channels, Ny / 2 +1 steps of the cross section of the plate. The presented model and the method of its implementation makes it possible to determine the temperature of the air flows along the length of coolers that offers a choice of the geometric parameters.
25
Emelyanov, Slava. "Low-energy electromagnetic radiation as an indirect probe of black-hole evaporation." Nuclear Physics B 913 (December 2016): 318–26. http://dx.doi.org/10.1016/j.nuclphysb.2016.09.011.
26
Zeng, D. W., C. S. Xie, M. Dong, R. Jiang, X. Chen, A. H. Wang, J. B. Wang, and J. Shi. "Spinel-type ZnSb2O4 nanowires and nanobelts synthesized by an indirect thermal evaporation." Applied Physics A 79, no. 8 (December 2004): 1865–68. http://dx.doi.org/10.1007/s00339-004-2916-3.
27
Safe, Abdolah, Fatemeh Sabokkhiz, Mohamad Hosein Ramesht, Morteza Djamali, and Abdolmajid Naderi Beni. "Study Clastic Sediments and Evaporite Deposits’ Changes in the Sedimentary Core Lake Maharlou, Iran." Modern Applied Science 10, no. 4 (February 13, 2016): 1. http://dx.doi.org/10.5539/mas.v10n4p1.
Abstract:
The continental environments, lakes are proper for deposition locations of evaporites. Evaporite minerals are formed wherever the evaporation rate is more than incoming water to the basin. In this article the evaporate deposits (Calcite, Gypsum and Halite) are studied in a sedimentary core of Lake Maharlou, Zagros Mountains, South of Iran. The core sample treated for getting Magnetic Susceptibility values along with the core as well as basic sedimentological data including grain size, Total Organic Matter and carbonate contents. NaCl is determin ed by gravimetric analysis. Loss on Ignition is applied to measure and estimate the amount of (OC), (Ca) and (SO4) mineralogy of which is determined by SEM method. The exists a direct relation between evaporation deposit formation of lake water level reduction. Accordingly, the change in the sediment stratum indicating the level of evaporations. The results indicate a lower extant of gypsum than Ca and NaCl. The sequence of layers principle, changes in the shoreline (lake water level fluctuations) with respect to stratum zonation. Magnetic susceptibility level is directly related to the Silt layer thickness but also there is an indirect relation with the level of organically rich sediments’ occurrence and abundance.
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Chen, Xi, Yuanyuan Cui, Chao Wen, Bin Wang, and Wei-Lin Dai. "Continuous synthesis of methanol: heterogeneous hydrogenation of ethylene carbonate over Cu/HMS catalysts in a fixed bed reactor system." Chemical Communications 51, no. 72 (2015): 13776–78. http://dx.doi.org/10.1039/c5cc05030h.
Abstract:
Continuous fixed-bed catalytic hydrogenation of ethylene carbonate (EC) to methanol and ethylene glycol (EG), an emerging synthetic process of methanol via indirect conversion of CO2, was successfully performed over Cu/HMS catalysts prepared by the ammonia evaporation (AE) method.
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Ginzburg, Sivan, and Eliot Quataert. "Black widow evolution: magnetic braking by an ablated wind." Monthly Notices of the Royal Astronomical Society 495, no. 4 (May 11, 2020): 3656–65. http://dx.doi.org/10.1093/mnras/staa1304.
Abstract:
ABSTRACT Black widows are close binary systems in which a millisecond pulsar is orbited by a companion, a few per cent the mass of the sun. It has been suggested that the pulsar’s rotationally powered γ-ray luminosity gradually evaporates the companion, eventually leaving behind an isolated millisecond pulsar. The evaporation efficiency is determined by the temperature Tch ∝ F2/3 to which the outflow is heated by the flux F on a dynamical time-scale. Evaporation is most efficient for companions that fill their Roche lobes. In this case, the outflow is dominated by a cap around the L1 point with an angle θg ∼ (Tch/Tg)1/2, and the evaporation time is tevap = 0.46(Tch/Tg)−2 Gyr, where Tg > Tch is the companion’s virial temperature. We apply our model to the observed black widow population, which has increased substantially over the last decade, considering each system’s orbital period, companion mass, and pulsar spin-down power. While the original black widow (PSR B1957+20) evaporates its companion on a few Gyr time-scale, direct evaporation on its own is too weak to explain the overall population. We propose instead that the evaporative wind couples to the companion’s magnetic field, removes angular momentum from the binary, and maintains stable Roche lobe overflow. While a stronger wind carries more mass, it also reduces the Alfvén radius, making this indirect magnetic braking mechanism less dependent on the flux $t_{\rm mag}\propto t_{\rm evap}^{1/3}$. This reduces the scatter in evolution times of observed systems, thus better explaining the combined black widow and isolated millisecond pulsar populations.
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Petrovic, Milica, Martina Gilic, Jovana Cirkovic, Maja Romcevic, Nebojsa Romcevic, Jelena Trajic, and Ibrahim Yahia. "Optical properties of CuSe thin films - band gap determination." Science of Sintering 49, no. 2 (2017): 167–74. http://dx.doi.org/10.2298/sos1702167p.
Abstract:
Copper selenide thin films of three different thicknesses have been prepared by vacuum evaporation method on a glass substrate at room temperature. The optical properties of the films were investigated by UV-VIS-NIR spectroscopy and photoluminescence spectroscopy. Surface morphology was investigated by field-emission scanning electron microscopy. Copper selenide exhibits both direct and indirect transitions. The band gap for direct transition is found to be ~2.7 eV and that for indirect transition it is ~1.70 eV. Photoluminescence spectra of copper selenide thin films have also been analyzed, which show emission peaks at 530, 550, and 760 nm. The latter corresponds to indirect transition in investigated material.
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Ariani, Sri Retno Dwi, Endang Susilowati, Elfi Susanti VH, and Setiyani Setiyani. "ACTIVITY TEST OF GUAVA (Psidium guajava L.) LEAF METHANOL EXTRACT AS CONTRACEPTION ANTIFERTILITY TO WHITE MICE (Rattus norvegicus)." Indonesian Journal of Chemistry 8, no. 2 (June 17, 2010): 264–70. http://dx.doi.org/10.22146/ijc.21632.
Abstract:
The aim of this research is to know about if the guava (Psidium guajava L.) leaf methanol extract on 10.5 mg/mL and 21.0 mg/mL dossages indicate a positive test as contraception antifertility to white mice (Rattus norvegicus). The sample is guava leaf from Mungkid, Magelang Central of Java Indonesia. The animals experiment are the white mice on 140-300 g for female, 200-250 g for male and about 3 months of age in average. The steps of this research are : (1) preparing sample, i.e. washing, drying on to indirect sunlight and make the sample into powder, (2) isolation the guava leaf powder in soxhlet instrument with hexane, (3) evaporation the sample with rotary evaporator until guava leaf hexane extract produced, (4) maseration the sample with methanol, (5) evaporation the sample with rotary evaporator until guava leaf methanol extract produced, (6) conducting contraception antifertility activity test to guave leaf methanol extract on 10.5 mg/mL and 21.0 mg/mL dossages to mice white. The results of this research are guava leaf methanol extract on 10.5 mg/mL and 21.0 mg/mL dossages indicate a negative contraception antifertility test to white mice but in these dossages have indicated that an antiimplantation effect (the total natality of fetus is less than the total implantation site in mice white). Keywords: Guava leaf, contraseption antifertility, methanol extract, white mice, implantation
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Al-Sharafi, Z., S. Mohyeddine, Samir Osman Mohammed, and R. M. Kershi. "Structural and Optical Properties of Germanium Thin Films Prepared by the Vacuum Evaporation Technique." Physics Research International 2014 (February 17, 2014): 1–7. http://dx.doi.org/10.1155/2014/594968.
Abstract:
Germanium (Ge) thin films have been deposited onto the glass substrates by the vacuum evaporation technique. The effect of annealing temperature on the structural and optical properties of the germanium thin films was investigated. The structural and optical properties of thin films were characterized by XRD, SEM, and UV-Vis techniques. XRD results showed that the structure of the deposited thin films changed from amorphous phase for the films, which deposited at room temperature, to crystalline phase for the films, which deposited at high temperature. Optimum temperature to obtain a good crystalline structure was 525°C. The SEM image also showed that the crystallization of the thin films is increased with increasing of annealing temperature. Transmittance and reflectance spectral were used to calculate the absorption coefficient. Two absorption edges in two spectral regions were distinguished according to direct and indirect electron transitions. Energy band gap Eg was calculated by using the Tauc relationship for both direct and indirect electron transitions. The average value of Eg was equal to 0.79 eV and 0.61 eV for direct and indirect transitions, respectively.
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Steveler, E., H. Rinnert, X. Devaux, M. Dossot, and M. Vergnat. "Indirect excitation of Er3+ ions in silicon nitride films prepared by reactive evaporation." Applied Physics Letters 97, no. 22 (November 29, 2010): 221902. http://dx.doi.org/10.1063/1.3521279.
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Гулевский, В. А., Е. Н. Осипов, and В. П. Шацкий. "Cooling of the Tehnical Objects Using Water-Evaporation Coolers." НАУЧНЫЙ ЖУРНАЛ СТРОИТЕЛЬСТВА И АРХИТЕКТУРЫ, no. 2(58) (September 17, 2020): 20–28. http://dx.doi.org/10.36622/vstu.2020.58.2.002.
Abstract:
Постановка задачи. Рассматривается задача охлаждения воздуха технических объектов с помощью водоиспарительных охладителей рекуперативного принципа действия. Результаты. Выводится уравнение нестационарного теплового баланса ограниченного объема с технологическим оборудованием с учетом его охлаждения рекуперативными водоиспарительными охладителями. Представлены математическая модель теплофизических процессов в косвенных водоиспарительных воздухоохладителях рекуперативного принципа действия и метод ее реализации. Модель содержит дифференциальные уравнения в частных производных, описывающие перенос энергии и массы в каналах теплообменного блока. Выводы. В результате проведенных исследований установлено, что установки водоиспарительного охлаждения косвенно-рекуперативного типа позволят, не повышая влагосодержания воздуха, значительно снизить температуру в помещениях с технологическим оборудованием, выделяющим большое количество тепла. Экологическая чистота и невысокая стоимость охладительных установок подобного типа добавляют положительный эффект от их применения. Statement of the problem. The problem of air cooling of technical objects by means of water-evaporative coolers of the recuperative principle of action is considered. Results. The equation of unsteady thermal balance of limited volume with technological equipment is derived taking into account its cooling by recuperative water-evaporative coolers. The mathematical model of thermal physical processes in indirect water-evaporative air coolers of the recuperative principle of action and the method of its implementation are presented. The model contains partial differential equations describing the transfer of energy and mass in the channels of the heat exchange unit. Conclusions. As a result of the conducted studies, it is established that installations of water-evaporative cooling of indirect-recuperative type will allow one without increasing moisture content of air to considerably to reduce the temperature in rooms with the processing equipment allocating a large amount of heat. Environmental friendliness and a low cost of cooling units of this type add a positive effect from their application.
35
Yan, Ming, Xinnan Song, Jin Tian, Xuebin Lv, Ze Zhang, Xiaoyan Yu, and Shuting Zhang. "Construction of a New Type of Coal Moisture Control Device Based on the Characteristic of Indirect Drying Process of Coking Coal." Energies 13, no. 16 (August 12, 2020): 4162. http://dx.doi.org/10.3390/en13164162.
Abstract:
This paper presents an in-depth study on the indirect drying characteristics and interface renewal. By comparing the drying rate curve, it is found that shortening the surface drying stage, which contains a repeated evaporation-diffusion-condensation process of moisture, is the key to improve the total drying efficiency. By stirring the coal and realizing the interface renewal between the bottom layer and the surface layer, the drying efficiency reached seven times than that of static indirect drying. Based on indirect heat transfer with high heat and mass transfer rate, a new type of indirect heat transfer moving bed coal moisture control device is designed. At the same time, Fluent fluid mechanics software is used for mathematical modeling and simulation experiments. It is proved that the designed moving bed coal moisture control device has a good application prospect in coal pre-drying technology.
36
Jeon, Min-Ju. "Investigation of Heat Transfer and Pressure Drop for R744 in a Horizontal Smooth Tube of R744/R404A Hybrid Cascade Refrigeration System—Part 1: Intermediate Temperature Region." Energies 15, no. 6 (March 21, 2022): 2285. http://dx.doi.org/10.3390/en15062285.
Abstract:
In this study, the evaporation heat transfer characteristics of an intermediate temperature of R744 in a smooth horizontal tube, when operating as an indirect refrigeration system (IRS) among hybrid cascade refrigeration systems (HCRSs), are evaluated. Studies on the characteristics of intermediate-temperature evaporation heat transfer under the operating conditions of evaporators used in actual refrigeration systems, such as IRS, cascade refrigeration systems, and HCRS, used in supermarkets are lacking. Thus, this study provides basic data on the characteristics of evaporation heat transfer of R744 in the evaporators of refrigerators used in supermarkets. The tube employed to the evaporation experiment in this study was a horizontal smooth copper tube with a length of 8000 mm and an inner diameter of 11.46 mm. The experimental variables were measured over a wide range of mass flux of 200–500 kg/(m2·s), heat flux of 10–40 kW/m2, and saturation temperature of −40–0 °C. The main results are summarized as follows: (1) The application of Kandlikar’s correlation formula at an evaporation temperature of −20 °C in an IRS helps in a good prediction of the R744 evaporation heat transfer coefficient. (2) The pressure drop according to the heat and mass flux showed the same heat transfer coefficient trend, but the pressure drop at saturation temperature was different from the trend of heat transfer coefficient.
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Shutov, Vladimir, Robert E. Gieck, Larry D. Hinzman, and Douglas L. Kane. "Evaporation from land surface in high latitude areas: a review of methods and study results." Hydrology Research 37, no. 4-5 (August 1, 2006): 393–411. http://dx.doi.org/10.2166/nh.2006.022.
Abstract:
Evaporation (ET) from land surfaces in high latitudes is examined on a circumpolar perspective based upon the study results obtained in various environments, from boreal forest (taiga) to the high Arctic desert. Direct and indirect methods of evaporation measurement are reviewed, as well as numerous computational techniques. We have focused upon methods conveniently adopted for calculating evaporation when detailed information on meteorological conditions within the surface boundary layer is not available. These methods range from complicated ones, such as eddy correlation, energy balance and Penman equations, to empirical relationships between ET and incoming solar radiation. Great attention was paid to the principles of each method, especially those developed in Russia as they differ from most of the methods utilized internationally. For example, the Budyko–Zubenok empirical scheme is based upon the principle of potential evaporation, which is affected by soil moisture (SM). This relationship between ET and SM, expressed in terms of the field capacity, has been found to be non-linear; a complication that is not typically accounted for in traditional approaches. This paper also contains a brief review of a number of evaporation case studies including Alaska (USA), north-western Russia and Siberian taiga, Yukon basin (Canada), mountainous forest on Hokkaido Island (Japan), Canadian Arctic and glacierized basins of Greenland.
38
Liu, Qiuyu, Ying Yan, Lei Meng, Zhengyu Zhang, and Ping Zhou. "Influence of Airflow Disturbance on the Uniformity of Spin Coating Film Thickness on Large Area Rectangular Substrates." Coatings 12, no. 9 (August 26, 2022): 1253. http://dx.doi.org/10.3390/coatings12091253.
Abstract:
Spin coating is widely used to form a uniform film on a solid substrate. Airflow disturbance has been considered as one of the most influential factors of film thickness, especially for spin coating on large area noncircular substrates. However, the exact mechanism of airflow disturbance influence, such as air shear force effect or indirect effects on evaporation, so far, remains ambiguous. In this work, the influence mechanism of airflow disturbance on film uniformity on large rectangular substrates is studied. The experiment with airflow disturbance is artificially introduced and contrasts with the common spin coating conditions. Both numerical simulations and experiments show a causal relationship between airflow disturbances and the uniformity of the spin coating film. The film thickness and airflow field results show that the film uniformity is affected by solvent evaporation and air shear force caused by airflow disturbance. Additionally, evaporation inhibition and airflow disturbance results do not support the proposition that air shear forces can affect film uniformity, but that solvent evaporation is the primary factor affecting film thickness uniformity. These conclusions are beneficial to the understanding of the mechanism of airflow disturbance influence on the film thickness uniformity on large rectangular substrates.
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Havlík, Jan, and Tomáš Dlouhý. "Indirect Dryers for Biomass Drying—Comparison of Experimental Characteristics for Drum and Rotary Configurations." ChemEngineering 4, no. 1 (March 10, 2020): 18. http://dx.doi.org/10.3390/chemengineering4010018.
Abstract:
This paper focuses on indirect biomass drying. It compares the operating characteristics of a laboratory-scale drum dryer and a pilot-scale rotary dryer. Before the design of an industrial dryer for a specific material, it is important to experimentally prove the process and to determine the drying characteristics of the material. To verify the portability of experimental results for indirect dryers, a drum dryer with indirect electric heating in a laboratory scale was designed and built to test and study the process of indirect drying. Based on the results obtained on a small-scale device, a prototype of a pilot steam-heated rotary dryer was designed and manufactured. A broad range of experiments with green wood chips and wet bark from open-air storage with moisture contents of 50 to 65 wt % were carried out on both dryers. The drying curves indicating the process, the square and volumetric evaporation capacities, and the drying energy consumption were obtained and compared, and the feasibility of indirect drying for these tested types of biomass was confirmed.
40
Meggers, Forrest, Hongshan Guo, Eric Teitelbaum, Gideon Aschwanden, Jake Read, Nicholas Houchois, Jovan Pantelic, and Emanuele Calabrò. "The Thermoheliodome – “Air conditioning” without conditioning the air, using radiant cooling and indirect evaporation." Energy and Buildings 157 (December 2017): 11–19. http://dx.doi.org/10.1016/j.enbuild.2017.06.033.
41
BATISHCHEVA, Ksenia A., Yuliya N. Vympina, and Evgeniya G. ORLOVA. "The influence of laser treatment of aluminum-magnesium alloy surface on the ”self-assembly” of nanoparticles during the evaporation of colloidal solution." Tyumen State University Herald. Physical and Mathematical Modeling. Oil, Gas, Energy 7, no. 1 (2021): 26–43. http://dx.doi.org/10.21684/2411-7978-2021-7-1-26-43.
Abstract:
Establishing the characteristics of the self-assembly of micron and sub-micron particles when colloidal solution droplets evaporate from solid surfaces is an urgent problem. This is explained by the possibility of using these structures obtained by droplet technologies to create and optimize the production of direct and indirect liquid cooling devices, electronic and sensor working boards, current-conducting coatings, optical crystals, and chemo sensors. The method used in this study for processing of metals and alloys by laser radiation is prospective for controlling the processes at the liquid/gas/solid interface. This article aims to analyze the effect of laser processing of the widely used in the industry aluminum-magnesium alloy on the formation of a layer of particles during the droplet evaporation of colloidal solutions. The samples’ surfaces were processed by two methods: polished by tumbling and nanosecond laser pulses. The geometric parameters of the droplets of colloidal solutions evaporating from the samples’ surfaces were determined by the shadow method. To process the obtained shadow images, the Young — Laplace method was used. Using a scanning electron microscope, the authors have received the images of the particles’ layers formed due to the droplet evaporation of colloidal solutions. The experimental studies reveal the effect of texture formed on aluminum-magnesium alloy sample on the morphology of the layer of polystyrene nanoparticles during the droplet evaporation of colloidal solutions. Due to the self-assembly of particles, solid ring-like sediments are formed, which are elongated under the action of the capillary force parallel to the motion vector of the laser beam (when creating the texture). When the solvent evaporated from the solution droplet on the textured surface, in addition to the rings, a homogeneous layer of polystyrene particles was formed. This refers to the droplet evaporation of the solution. The results show that with an increase in the concentration of particles in the solution, the sizes of radial cracks on the rings formed due to particle deposition increase. There were no cracks on the rings at a relatively low volume concentration of particles.
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Alamri, Saleh N., and Ahamed A. Joraid. "Smart Windows with Different Thicknesses of V2O5 as Ion Storage Layers." Materials Science Forum 663-665 (November 2010): 743–50. http://dx.doi.org/10.4028/www.scientific.net/msf.663-665.743.
Abstract:
Smart windows were fabricated with different thicknesses of amorphous V2O5, which acts as an ion storage layer. In these devices, V2O5 was deposited by thermal evaporation at a substrate temperature of 200 oC, and an electrochromic layer (WO3) was deposited by electron beam evaporation at a substrate temperature of 250 oC. Both layers were amorphous. V2O5 was found to exhibit direct-forbidden electron transitions, whereas the WO3 layer exhibited indirect-allowed electron transitions. An increase in the thickness of V2O5 from 78 nm to 313 nm reduced the colouration efficiency from 64 to 48 cm2/C, and the time of the transmission variation curve from the coloured state to the bleached state was increased from 82.41 s to 558 s.
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Taler, Jan, Bartosz Jagieła, and Magdalena Jaremkiewicz. "Overview of the M-Cycle Technology for Air Conditioning and Cooling Applications." Energies 15, no. 5 (March 1, 2022): 1814. http://dx.doi.org/10.3390/en15051814.
Abstract:
The indirect evaporative cooler (IEC) has excellent potential to replace or improve conventional vapor compression equipment in HVAC and refrigeration applications. This could be achieved by using the M-cycle (dew-point evaporative cooling technology). This thermodynamic concept makes it possible to derive a large amount of energy from the air stream (as latent heat released during water evaporation into the working air stream) and use it for another air stream (product). Its application has also spread to other sectors, such as water desalination and distillation, power plants, or NOx reduction. This paper provides an overview of the M-cycle mainly in air conditioning (MAC, D-MAC, H-MAC) and refrigeration (MCT, M-condenser). Various integrated solutions are described, showing improved effectiveness in terms of the wet-bulb temperature and the dew point. The design features of consolidated solutions are better In terms of the flow distribution, geometry, or volume. Most of the improvements confirm the great potential of the M-cycle to increase the unit or the system efficiency due to lower energy and water consumption.
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Asfahan, Hafiz M., Uzair Sajjad, Muhammad Sultan, Imtiyaz Hussain, Khalid Hamid, Mubasher Ali, Chi-Chuan Wang, Redmond R. Shamshiri, and Muhammad Usman Khan. "Artificial Intelligence for the Prediction of the Thermal Performance of Evaporative Cooling Systems." Energies 14, no. 13 (July 1, 2021): 3946. http://dx.doi.org/10.3390/en14133946.
Abstract:
The present study reports the development of a deep learning artificial intelligence (AI) model for predicting the thermal performance of evaporative cooling systems, which are widely used for thermal comfort in different applications. The existing, conventional methods for the analysis of evaporation-assisted cooling systems rely on experimental, mathematical, and empirical approaches in order to determine their thermal performance, which limits their applications in diverse and ambient spatiotemporal conditions. The objective of this research was to predict the thermal performance of three evaporation-assisted air-conditioning systems—direct, indirect, and Maisotsenko evaporative cooling systems—by using an AI approach. For this purpose, a deep learning algorithm was developed and lumped hyperparameters were initially chosen. A correlation analysis was performed prior to the development of the AI model in order to identify the input features that could be the most influential for the prediction efficiency. The deep learning algorithm was then optimized to increase the learning rate and predictive accuracy with respect to experimental data by tuning the hyperparameters, such as by manipulating the activation functions, the number of hidden layers, and the neurons in each layer by incorporating optimizers, including Adam and RMsprop. The results confirmed the applicability of the method with an overall value of R2 = 0.987 between the input data and ground-truth data, showing that the most competent model could predict the designated output features (Toutdb, wout, and Eoutair). The suggested method is straightforward and was found to be practical in the evaluation of the thermal performance of deployed air conditioning systems under different conditions. The results supported the hypothesis that the proposed deep learning AI algorithm has the potential to explore the feasibility of the three evaporative cooling systems in dynamic ambient conditions for various agricultural and livestock applications.
45
Xue, Huiwen, and Graham Feingold. "Large-Eddy Simulations of Trade Wind Cumuli: Investigation of Aerosol Indirect Effects." Journal of the Atmospheric Sciences 63, no. 6 (June 1, 2006): 1605–22. http://dx.doi.org/10.1175/jas3706.1.
Abstract:
Abstract The effects of aerosol on warm trade cumulus clouds are investigated using a large-eddy simulation with size-resolved cloud microphysics. It is shown that, as expected, increases in aerosols cause a reduction in precipitation and an increase in the cloud-averaged liquid water path (LWP). However, for the case under study, cloud fraction, cloud size, cloud-top height, and depth decrease in response to increasing aerosol concentration, contrary to accepted hypotheses associated with the second aerosol indirect effect. It is found that the complex responses of clouds to aerosols are determined by competing effects of precipitation and droplet evaporation associated with entrainment. As aerosol concentration increases, precipitation suppression tends to maintain the clouds and lead to higher cloud LWP, whereas cloud droplets become smaller and evaporate more readily, which tends to dissipate the clouds and leads to lower cloud fraction, cloud size, and depth. An additional set of experiments with higher surface latent heat flux, and hence higher LWP and drizzle rate, was also performed. Changes in cloud properties due to aerosols have the same trends as in the base runs, although the magnitudes of the changes are larger. Evidence for significant stabilization (or destabilization) of the subcloud layer due to drizzle is not found, mainly because drizzling clouds cover only a small fraction of the domain. It is suggested that cloud fraction may only increase with increasing aerosol loading for larger clouds that are less susceptible to entrainment and evaporation. Finally, it is noted that at any given aerosol concentration the dynamical variability in bulk cloud parameters such as LWP tends to be larger than the aerosol-induced changes in these parameters, indicating that the second aerosol indirect effect may be hard to measure in this cloud type. The variability in cloud optical depth is, however, dominated by changes in aerosol, rather than dynamics.
46
Vorobevskii, Ivan, Thi Thanh Luong, Rico Kronenberg, Thomas Grünwald, and Christian Bernhofer. "Modelling evaporation with local, regional and global BROOK90 frameworks: importance of parameterization and forcing." Hydrology and Earth System Sciences 26, no. 12 (June 22, 2022): 3177–239. http://dx.doi.org/10.5194/hess-26-3177-2022.
Abstract:
Abstract. Evaporation plays an important role in the water balance on a different spatial scale. However, its direct and indirect measurements are globally scarce and accurate estimations are a challenging task. Thus the correct process approximation in modelling of the terrestrial evaporation plays a crucial part. A physically based 1D lumped soil–plant–atmosphere model (BROOK90) is applied to study the role of parameter selection and meteorological input for modelled evaporation on the point scale. Then, with the integration of the model into global, regional and local frameworks, we made cross-combinations out of their parameterization and forcing schemes to show and analyse their roles in the estimations of the evaporation. Five sites with different land uses (grassland, cropland, deciduous broadleaf forest, two evergreen needleleaf forests) located in Saxony, Germany, were selected for the study. All tested combinations showed a good agreement with FLUXNET measurements (Kling–Gupta efficiency, KGE, values 0.35–0.80 for a daily scale). For most of the sites, the best results were found for the calibrated model with in situ meteorological input data, while the worst was observed for the global setup. The setups' performance in the vegetation period was much higher than for the winter period. Among the tested setups, the model parameterization showed higher spread in performance than meteorological forcings for fields and evergreen forests sites, while the opposite was noticed in deciduous forests. Analysis of the of evaporation components revealed that transpiration dominates (up to 65 %–75 %) in the vegetation period, while interception (in forests) and soil/snow evaporation (in fields) prevail in the winter months. Finally, it was found that different parameter sets impact model performance and redistribution of evaporation components throughout the whole year, while the influence of meteorological forcing was evident only in summer months.
47
Rodrigues, Carlos Miranda, Madalena Moreira, Rita Cabral Guimarães, and Miguel Potes. "Reservoir evaporation in a Mediterranean climate: comparing direct methods in Alqueva Reservoir, Portugal." Hydrology and Earth System Sciences 24, no. 12 (December 17, 2020): 5973–84. http://dx.doi.org/10.5194/hess-24-5973-2020.
Abstract:
Abstract. Alqueva Reservoir is one of the largest artificial lakes in Europe and is a strategic water storage for public supply, irrigation, and energy generation. The reservoir is integrated within the Multipurpose Alqueva Project (MAP), which includes almost 70 reservoirs in a water-scarce region of Portugal. The MAP contributes to sustainability in southern Portugal and has an important impact on the entire country. Evaporation is the key component of water loss from the reservoirs included in the MAP. Evaporation from Alqueva Reservoir has been estimated by indirect methods or pan evaporation measurements; however, specific experimental parameters such as the pan coefficient were never evaluated. Eddy covariance measurements were performed at Alqueva Reservoir from June to September in 2014 as this time of the year provides the most representative evaporation volume losses in a Mediterranean climate. This period is also the most important period for irrigated agriculture and is, therefore, the most problematic period of the year in terms of managing the reservoir. The direct pan evaporation approach was first tested, and the results were compared to the eddy covariance evaporation measurements. The total eddy covariance (EC) evaporation measured from June to September 2014 was 450.1 mm. The mean daily EC evaporation in June, July, August, and September was 3.7, 4.0, 4.5, and 2.5 mm d−1, respectively. A pan coefficient, Kpan, multivariable function was established on a daily scale using the identified governing factors: air temperature, relative humidity, wind speed, and incoming solar radiation. The correlation between the modelled evaporation and the measured EC evaporation had an R2 value of 0.7. The estimated Kpan values were 0.59, 0.57, 0.57, and 0.64 in June, July, August, and September, respectively. Consequently, the daily mean reservoir evaporation (ERes) was 3.9, 4.2, 4.5, and 2.7 mm d−1 for this 4-month period and the total modelled ERes was 455.8 mm. The developed Kpan function was validated for the same period in 2017 and yielded an R2 value of 0.68. This study proposes an applicable method for calculating evaporation based on pan measurements in Alqueva Reservoir, and it can be used to support regional water management. Moreover, the methodology presented here could be applied to other reservoirs, and the developed equation could act as a first evaluation for the management of other Mediterranean reservoirs.
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Journal, Baghdad Science. "Fabrication of multi-junction solar cells." Baghdad Science Journal 11, no. 2 (June 1, 2014): 614–20. http://dx.doi.org/10.21123/bsj.11.2.614-620.
Abstract:
Fabrication of solar cell prepared by thermal spray and vacuum thermal evaporation method on silicon wafer(n-type) and studying its efficiency. The film have been deposited on three layers(ZnO then CdS and CdTe) on Si and glass respectively.Direct energy gap was calculated and equal to (4.3,3.4,3)eV and indirect energy gap equal to (3.5,2.5,1.5)eV respectively . Efficiency was calculated for the cell of area 2cm2 it was equal to 0.14%.
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Abood, Morooj A., Falah I. Mustafa, MarwaR Fraih, and Mstafa D. Abduljaber. "Fabrication of multi-junction solar cells." Baghdad Science Journal 11, no. 2 (June 1, 2014): 614–20. http://dx.doi.org/10.21123/bsj.2014.11.2.614-620.
Abstract:
Fabrication of solar cell prepared by thermal spray and vacuum thermal evaporation method on silicon wafer(n-type) and studying its efficiency. The film have been deposited on three layers(ZnO then CdS and CdTe) on Si and glass respectively.Direct energy gap was calculated and equal to (4.3,3.4,3)eV and indirect energy gap equal to (3.5,2.5,1.5)eV respectively . Efficiency was calculated for the cell of area 2cm2 it was equal to 0.14%.
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Mullan, Daniel J., and Matthew P. Reynolds. "Quantifying genetic effects of ground cover on soil water evaporation using digital imaging." Functional Plant Biology 37, no. 8 (2010): 703. http://dx.doi.org/10.1071/fp09277.
Abstract:
Rapid development of leaf area and/or aboveground biomass has the potential to improve water harvest of rain fed wheat in Mediterranean-type environments through reduced soil evaporation. However, quantitative relationships between genetic differences in early ground cover and soil water evaporation have not been established. Furthermore, accurate phenotyping of ground cover and early vigour have typically been achieved via destructive sampling methods, which are too time-consuming to undertake within breeding programs. Digital image analysis has previously been identified as an alternative indirect method of analysis, whereby computer analysis is ued to determine percentage ground cover. This study uses a digital ground cover (DGC) analysis tool for high throughput screening of four large wheat populations. The DGC methodology was validated via comparisons with alternative measures of canopy cover, such as normalised difference vegetation index (NDVI) (r2 = 0.69), biomass (r2 = 0.63), leaf area index (r2 = 0.80) and light penetration through the canopy (r2 = 0.70). The wheat populations were utilised to estimate the potential variation in soil evaporation associated with genetic differences in early ground cover, which was validated using established models. Estimates of genetic differences in soil evaporation within the four populations (6.90–24.8 mm) suggest that there is sufficient genetic variation to increase water harvest through targeting faster ground cover. Implications for improved wheat yields and breeding are discussed.