Journal articles on the topic 'Evaporatore'
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1
Rachman, Arfidian, and Lisa Nesti. "Experimental Study to Performance Improvement of Vapor Compression Cooling System Integrated Direct Evaporative Cooler and Condenser." MATEC Web of Conferences 215 (2018): 01017. http://dx.doi.org/10.1051/matecconf/201821501017.
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For areas with very hot and humid weather condition increased latent and sensible load are a major problem in cooling systems that will increase compressor work so that electricity consumption will also increase. Combined condenser with direct evaporate cooling will increase the heat removal process by using an evaporative cooler effect that will increase the efficiency of energy use. This paper presents the study of the use of evaporator cooling and condenser. This paper mainly calculated energy consumption in steam compression cooling systems and related problems. From the results of this study, the use of condensers with evaporative cooling, power consumption can be reduced to 46% and performance coefficient (COP) can be increased by about 12%, with 1,2 kW cooling capacity.
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Permatasari, Rosyida, Muhammad Alwan Ridhoarto, Sally Cahyati, and Martinus Bambang Susetyarto. "Determining Position of the Evaporator in a Smart Classroom Concept Using CFD Method." International Journal of Electrical, Energy and Power System Engineering 4, no. 3 (October 31, 2021): 179–84. http://dx.doi.org/10.31258/ijeepse.4.3.178-184.
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Various, different evaporator placements in a room have produced different airflow patterns, temperature distribution, and airflow velocities. In this study, the average room temperature and airflow velocity measured at 27 points of the CFD simulation for 4 positions of the planned evaporator placements were compared to determine the most ideal position based on the comfortable temperature and the maximum airflow velocity pursuant to the SNI 03-6572-2001 recommendation. On Position 1, two evaporators were given to the west wall. Position 2, two evaporators were placed on the south wall. On Position 3, two evaporators were given to the north wall. Moreover, on Position 4, two evaporators were placed opposite to each other where an evaporator was placed on the south wall, and the other evaporator was placed on the north wall. An ANSYS Fluent software was employed to make the CFD simulation. Based on the results of the study, it was found out that Position 2 was the most ideal evaporator placement position since it met the comfortable temperature limit and has the highest number of airflow velocity points meeting the recommended maximum airflow velocity pursuant to the SNI 03-6572-2001 recommendation.
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Smith, R. A., and P. D. Hills. "3.5.2 EVAPORATORS: TYPES OF EVAPORATOR." Heat Exchanger Design Updates 8, no. 2 (2001): 12. http://dx.doi.org/10.1615/heatexchdesignupd.v8.i2.20.
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Riadi, Indra, Zulfan Adi Putra, and Heri Cahyono. "Thermal integration analysis and improved configuration for multiple effect evaporator system based on pinch analysis." Reaktor 21, no. 2 (August 11, 2021): 74–93. http://dx.doi.org/10.14710/reaktor.21.2.74-93.
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Pinch analysis for a sugar plant production capacity 4000 TCD has been carried out to reduce its energy consumptions. The plant has ten evaporators that can be configured to several multiple effect evaporators. It has been running with five-effect evaporator (quintuple) scheme. To maximize energy utilization within the plant, three multiple effect evaporator schemes were evaluated. They are triple effect evaporator, quadruple effect evaporator, and quintuple effect evaporator as the benchmark. The result shows that the quintuple effect evaporator yields the highest energy efficiency by about 10%. Options to achieve such target is to use low pressure steam only for the first effect and to use steam bleeding from the first effect to heat a tertiary juice heater. With this proposed scenario, sugar dryer, wash water RVF unit and wash water HGF unit no longer need external steam for its operation.
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Chantasiriwan, Somchart. "Increased Energy Efficiency of a Backward-Feed Multiple-Effect Evaporator Compared with a Forward-Feed Multiple-Effect Evaporator in the Cogeneration System of a Sugar Factory." Processes 8, no. 3 (March 16, 2020): 342. http://dx.doi.org/10.3390/pr8030342.
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The cogeneration system of a sugar factory consists of boiler, steam turbine, and sugar juice evaporation process. The multiple-effect evaporator used for the conventional sugar juice evaporation process is the forward-feed multiple-effect evaporator, in which steam and sugar juice flow in the same direction. The main objective of this paper is to investigate the energy efficiency of the backward-feed multiple-effect evaporator, in which steam and sugar juice flow in opposite directions, compared with that of the forward-feed multiple-effect evaporator. Mathematical models are developed for both multiple-effect evaporators, and used to compare the performances of two cogeneration systems that use the forward-feed and backward-feed multiple-effect evaporators. The forward-feed multiple-effect evaporator requires extracted steam from a turbine at one pressure, whereas the backward-feed multiple-effect evaporator requires steam extraction at two pressures. Both evaporators have the same total heating surface area, process the same amount of sugar juice, and operate at the optimum conditions. It is shown that the cogeneration system that uses the backward-feed multiple-effect is more energy efficient than the cogeneration system that uses the forward-feed multiple-effect because it yields more power output for the same fuel consumption.
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Trinh, Ngoc Van, Younghyeon Kim, Hongjip Kim, and Sangseok Yu. "Evaporation of Methanol Solution for a Methanol Steam Reforming System." Energies 14, no. 16 (August 9, 2021): 4862. http://dx.doi.org/10.3390/en14164862.
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In a methanol-reforming system, because the mixture of methanol and water must be evaporated before reaching the reforming reaction zone, having an appropriate evaporator design is a fundamental requirement for completing the reforming reaction. This study investigates the effect of the evaporator design for the stable reforming of methanol–water mixtures. Four types of evaporator are compared at the same heat duty of the methanol-reforming system. The four evaporators are planar heat exchangers containing a microchannel structure, cylindrical shell-and-tube evaporators, zirconia balls for internal evaporation, and combinations of cylindrical shell-tubes and zirconia balls. The results show that the evaporator configuration is critical in performing stable reform reactions, especially for the flow-field mode of the evaporator. Additionally, the combination of both internal and external evaporation methods generates the highest performance for the methanol-reforming system, with the methanol conversion reaching almost 98%.
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Fei, Ji You, Qi Chao Guo, Hua Li, and Ran Deng. "Study on the Intervascular Two-Phase Flow Characters of Horizontal-Tube Falling Film Evaporator." Advanced Materials Research 516-517 (May 2012): 208–11. http://dx.doi.org/10.4028/www.scientific.net/amr.516-517.208.
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In this paper, the mathematical model of a horizontal-tube falling film evaporator that used in air condition and refrigeration system was founded. The evaporative tubes of the evaporator were cold and staggered arrangement. The numerical simulation of the intervascular flow of the oil-bearing refrigerant R134a was carried out, under the conditions of varies flow mode and varies structures of distributed equipment. Under the standard condition of air conditioning, the study of the intervascular two-phase flow characters of the horizontal-tube falling film evaporator were analyzed in the last. The research achievements can provide theoretical laws for relief the effects of the intervascular vapor shear stress on the quality of the liquid film formed outside the evaporative tubes. And the conclusions have practical and guide means for the horizontal-tube falling film evaporator design and evaporative tubes arrangement optimization.
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Yang, Maoli, Xianyun Wu, Wenping Zhou, Xiangshu Liu, Rui Qiang, and Fuchuan Huang. "Experimental Study on Effects of Different Water Flow Rates on Heat Transfer Characteristics of Evaporator." Journal of Physics: Conference Series 2418, no. 1 (February 1, 2023): 012003. http://dx.doi.org/10.1088/1742-6596/2418/1/012003.
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Abstract Since China set forth the goal of “dual carbon”, studies on heat transfer characteristics of evaporators have been one of the hot spots in the field of refrigeration and heating. This paper conducts an experimental study on the heat transfer performances of evaporators under different flow rates by changing the water flow of the evaporator and condenser. The results shows that on the premise of unchanged water flow of condenser, cooling coefficient of performance (COP) and heat transfer coefficient (HTC) grow with the increases in flow rates of evaporator and temperatures of inlet and outlet water. However, the changes in HTC are relatively smooth; the compressor’s inhalation and expulsion temperatures grow with the increases in water flow rates of the evaporator, and the changes are quite evident. The paper also discusses and analyzes deeply those manifestations, which provides experimental evidence for the experiments and improvement of the evaporator, optimization of evaporator design, and the enhancement of the economic performance of the system.
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O’Reilly, J. M., and P. F. Monaghan. "Wind Evaporator Heat Pumps—Part II: Thermal Performance Results." Journal of Energy Resources Technology 114, no. 4 (December 1, 1992): 286–90. http://dx.doi.org/10.1115/1.2905955.
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Wind evaporators are alternative evaporators for air source heat pumps which rely on wind-driven or natural convection to move air across the heat transfer surfaces. A fully automatic, computer-controlled test facility which allows side-by-side testing of wind evaporator and conventional heat pumps and monitoring of weather conditions has been designed and built at University College Galway. The aim of this paper is to quantify the advantages of wind evaporators by comparing the performance of a wind evaporator heat pump with that of a conventional heat pump over an extended testing period and by examining the relationship between weather conditions and heat pump performance. In this paper, results are presented in the form of plots of coefficient of performance (COP), compressor power, evaporator and condenser heat transfers and climatic variables against time. In addition, a testing period coefficient of performance has been calculated for each heat pump. The results show that wind speed is the dominant climatic variable affecting wind evaporator heat pump performance, and that frost growth does not significantly reduce this performance. Even at extremely low wind speeds, the COP of the wind evaporator heat pump is not significantly affected. After over 460 hr of testing, the testing period COP of the wind evaporator heat pump shows a 16 percent increase over that of the conventional heat pump. (Refer to Nomenclature in Part I of this paper.)
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Monaghan, P. F., D. P. Finn, and J. M. O’Reilly. "Wind Evaporator Heat Pumps—Part I: Test Methods." Journal of Energy Resources Technology 114, no. 4 (December 1, 1992): 281–85. http://dx.doi.org/10.1115/1.2905954.
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Wind evaporators are alternative evaporators for air source heat pumps which rely on wind-driven or natural convection to move air across the heat transfer surfaces. It is believed that, in certain climates, wind evaporators can operate satisfactorily with frost on their surfaces for extended periods of time and defrost passively during switch-off periods. If so, an active defrost cycle would be unnecessary in these climates. Wind evaporators present an opportunity for heat pumps to be less expensive, more reliable, and more energy-efficient. However, the heat transfer performance of wind evaporators varies as a result of changes in a wide range of climatic variables. To determine the technical feasibility of wind evaporators, it is necessary to test complete wind evaporator heat pumps and to compare their monitored field performance over extended periods to that of conventional heat pumps with fan-assisted, finned-tube evaporators. In this paper, a test facility which allows side-by-side testing of wind evaporator and conventional heat pumps and monitoring of weather conditions is described. The choice of measurement technique for each variable is discussed and estimates of the measurement uncertainty for each sensor are made.
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CANTRELL, JAMES G. "Black liquor evaporator upgrades— life cycle cost analysis." March 2021 20, no. 3 (April 1, 2021): 208–21. http://dx.doi.org/10.32964/tj20.3.208.
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Black liquor evaporation is generally the most energy intensive unit operation in a pulp and paper manufacturing facility. The black liquor evaporators can represent a third or more of the total mill steam usage, followed by the paper machine and digester. Evaporator steam economy is defined as the unit mass of steam required to evaporate a unit mass of water from black liquor (i.e., lb/lb or kg/kg.) The economy is determined by the number of effects in an evaporator train and the system configuration. Older systems use four to six effects, most of which are the long tube vertical rising film type. Newer systems may be designed with seven or even eight effects using falling film and forced circulation crystallization technology for high product solids. The median age of all North American evaporator systems is 44 years. Roughly 25% of the current North American operating systems are 54 years or older. Older systems require more periodic maintenance and have a higher risk of unplanned downtime. Also, older systems have chronic issues with persistent liquor and vapor leaks, shell wall thinning, corrosion, and plugged tubes. Often these issues worsen to the point of requiring rebuild or replacement. When considering the age, technology, and lower efficiency of older systems, a major rebuild or new system may be warranted. The intent of this paper is to review the current state of black liquor evaporator systems in North America and present a basic method for determining whether a major rebuild or new installation is warranted using total life cycle cost analysis (LCCA).
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Lee, Cho Han, and Yao Yang Tsai. "Measurement of Thin-Film Evaporation Heat Transfer for Evaporators with Sintered Powder Wick Structure." Advanced Materials Research 579 (October 2012): 379–86. http://dx.doi.org/10.4028/www.scientific.net/amr.579.379.
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Two-phase heat transfer devices such as heat pipes and vapor chambers are composed of an evaporator, an adiabatic section and a condenser. For the dry-out prevention and capillary purpose, adiabatic sections and evaporators are covered by wick structures. Common wick structures are grooves, mesh, sintered powder and their combination. Combining with the wick structures, the major phase change effects on evaporators are thin-film evaporation. For the research between parameters of wick structure and evaporator performance, we developed a facility to measure the heat transfer on evaporators. To ensure the least heat losing, the path of heat flux and test condition were designed with several thermal guards. A pressure control system was established with balance mechanisms to maintain a stable condition of low pressure. Since temperature differences are very fast while the major phase change effect is thin-film evaporation, a high speed data acquisition system was used. Based on this test platform, the performance of evaporators can be determined at specific conditions.
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Miyatake, O., T. Tomimura, and Y. Ide. "Enhancement of Spray Flash Evaporation by Means of the Injection of Bubble Nuclei." Journal of Solar Energy Engineering 107, no. 2 (May 1, 1985): 176–82. http://dx.doi.org/10.1115/1.3267673.
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Spray flash evaporators are being used or considered for power systems utilizing solar energy, ocean thermal energy, and geothermal energy. As part of an attempt to develop a compact, efficient flash evaporator, an experimental study of the effect of injection of bubble nuclei has been conducted. The bubble nuclei were generated by electrolyzing warm water, which was ejected from a simple tubular nozzle into a low-pressure vapor zone. Effects of electrolytic current level, nozzle diameter, liquid flow rate, liquid temperature, and superheat were investigated. The evaporator rates attained were superior to those in conventional multistage flash evaporators with open channels.
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Mankonen, Aleksi, Juha Kaikko, Esa Vakkilainen, and Vitaliy Sergeev. "Thermodynamic analysis of a condensing evaporator in an evaporative gas turbine cycle." MATEC Web of Conferences 245 (2018): 07007. http://dx.doi.org/10.1051/matecconf/201824507007.
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Low efficiency is the main stumbling block preventing the widespread adoption of small-scale gas turbines in distributed energy production. The evaporative gas turbine cycle has been proposed as a way to improve efficiency, but the large number of components required make the configuration complex and expensive. The condensing evaporator is a component that simplifies the evaporative gas turbine cycle. The heat and mass exchanger device is designed for an externally fired application, which means that the flue gas stream is replaced by moist air. The air-water mixture condenses inside a tube bank, releasing heat to the evaporating water film on the other side of the tubes. Similar inventions include the tubular humidifier and the Maisotsenko compressed air saturator, which also aim to make the evaporative gas turbine cycle more economically feasible. Available theory focuses on either humidification towers or evaporative condensers in HVAC applications. The tubular humidifier has been analyzed in a similar manner as humidification tower since the flow configurations of the two components are similar. However, the theory of humidification towers is not directly applicaple to the condensing evaporator. This study proposes a method of analysis of the condensing evaporator in power generation.
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Белогуров, С. А. "КРИЗИС ТЕПЛООТДАЧИ В ЖИДКОМЕТАЛЛИЧЕСКИХ ИСПАРИТЕЛЯХ С СОСТАВНОЙ КАПИЛЛЯРНО-ПОРИСТОЙ СТРУКТУРОЙ В ВЫХОДНОМ СЕЧЕНИИ." Journal of Rocket-Space Technology 26, no. 4 (September 5, 2018): 15–19. http://dx.doi.org/10.15421/451803.
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Results of experimental research represent conditions of heat transfer deterioration for boiling potassium in a straight-through evaporator with a composite capillary-porous structure in the output section. A region of mass velocities is identified, where boundary vapor content, with heat transfer deterioration in the composite capillary-porous structure, is higher than in smooth-tube evaporators and evaporators with a simple capillary structure.
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Mishra, R. S., and S. S. Kachhwaha. "Thermodynamic Irreversibilities Analysis of Industrial Ice Plant." International Journal of Advance Research and Innovation 2, no. 4 (2014): 83–92. http://dx.doi.org/10.51976/ijari.241413.
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The behavior of single-stage vapour compression-refrigeration cycle, using NH3, has been investigated by the exergy method. The condenser and the evaporator’s saturation temperatures were varied from 295 K to 305 K and from 249 K to 239 K respectively. The effects of temperature changes in the condenser and evaporator on the plant’s irreversibility rate were determined. The greater the temperature difference between either (i) the condenser and the environment, or (ii) the evaporator and the cold room, the higher the irreversibility rate. Reduction in the irreversibility rate of the condenser gives approximately 2.58 times greater reduction in the irreversibility rate for the whole plant, whereas reduction in the evaporator’s irreversibility rate gives a 2.32 times greater mean reduction in the irreversibility rate of the whole plant. Because the changes in the temperatures in the condenser and the evaporator contribute significantly to the plant’s overall irreversibility, there is considerable scope for optimizing the condition imposed upon the condenser and evaporator.
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Gao, Shenyue, Yuetong Tao, Gang Wang, Hui Wang, Jinbo Bai, Beibei Wang, and Shenghua Ma. "Janus interpenetrating structure based on optimized water supply for solar-driven water evaporation." Applied Physics Letters 120, no. 25 (June 20, 2022): 253903. http://dx.doi.org/10.1063/5.0085688.
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Realizing a balance between water supply and the evaporation of photothermal evaporators is a valuable means to enhance the solar–thermal evaporation rate, but practical obstacles remain. The interfacial mechanics of a Janus evaporator with an interpenetrating structure are proposed to achieve a dramatic improvement in the solar–thermal evaporation rate. The Janus evaporator is composed of a membrane material of Cu1.96S grown in situ on a foamed copper skeleton (CF@Cu1.96S) and a graphene oxide/sodium alginate aerogel (GA), through an interfacial freeze-drying shape technology. In this unique architecture, the superhydrophilic GA can be stretched into the hydrophobic CF@Cu1.96S interior to build an interpenetrating network architecture (CF@Cu1.96S/GA), thereby adjusting the Laplace pressure and constraining capillarity. Due to the optimized water supply of interfacial mechanics, the CF@Cu1.96S/GA evaporator achieves an evaporation rate of 1.79 kg m−2 h−1 under 1 sun irradiation and exhibits superior salt resistance. This provides a rationale for the reasonable design of the structure of the solar–thermal evaporators.
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Yu, Dongjin, Ngoc Trinh Van, Jinwon Yun, and Sangseok Yu. "A Thermal Design of a 1 kW-Class Shell and Tube Methanol Steam Reforming System with Internal Evaporator." Processes 8, no. 11 (November 20, 2020): 1509. http://dx.doi.org/10.3390/pr8111509.
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Due to its low operating temperature, the performance of a methanol steam reformer depends on efficient thermal integration. In particular, the integration of the evaporator is crucial to enhance thermal efficiency. This paper presents two different configurations to utilize thermal energy for evaporation of methanol/water mixture. The reformer system is composed of a methanol steam reformer, a burner, and two different evaporators such as internal evaporator and external evaporator. Moreover, since the performance of the reforming system strongly depends on thermal utilization, a heat recovery module is designed for methanol reforming system with internal evaporator. The heat duty and steam to carbon ratio (S/C) are the variables for evaluation of its suitability. The experimental results indicate that the internal evaporator with the auxiliary heat recovery module provides stable conditions over wide operating ranges.
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Szymanski, Pawel, Richard Law, Ryan MᶜGlen, and David Reay. "Recent Advances in Loop Heat Pipes with Flat Evaporator." Entropy 23, no. 11 (October 20, 2021): 1374. http://dx.doi.org/10.3390/e23111374.
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The focus of this review is to present the current advances in Loop Heat Pipes (LHP) with flat evaporators, which address the current challenges to the wide implementation of the technology. A recent advance in LHP is the design of flat-shaped evaporators, which is better suited to the geometry of discretely mounted electronics components (microprocessors) and therefore negate the need for an additional transfer surface (saddle) between component and evaporator. However, various challenges exist in the implementation of flat-evaporator, including (1) deformation of the evaporator due to high internal pressure and uneven stress distribution in the non-circular casing; (2) heat leak from evaporator heating zone and sidewall into the compensation chamber; (3) poor performance at start-up; (4) reverse flow through the wick; or (5) difficulties in sealing, and hence frequent leakage. This paper presents and reviews state-of-the-art LHP technologies; this includes an (a) review of novel manufacturing methods; (b) LHP evaporator designs; (c) working fluids; and (d) construction materials. The work presents solutions that are used to develop or improve the LHP construction, overall thermal performance, heat transfer distance, start-up time (especially at low heat loads), manufacturing cost, weight, possibilities of miniaturization and how they affect the solution on the above-presented problems and challenges in flat shape LHP development to take advantage in the passive cooling systems for electronic devices in multiple applications.
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Mrihardjono, Juli, Didik Ariwibowo, Sutrisno Sutrisno, and Dista Yoel Tadeus. "EFEK PENAMBAHAN EVAPORATOR PADA ATMOSPHERE WATER HARVESTER (AWH) TERHADAP PERFORMA SISTEM." Gema Teknologi 21, no. 2 (April 30, 2021): 74–80. http://dx.doi.org/10.14710/gt.v21i2.33448.
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Atmosphere Water Harvester (AWH) was investigated to get water collected from air in elevated performance. Improvement was performed by introducing a series-arrangement of two evaporators. Air flew through the evaporators in cross-flow. This arrangement would influence performance of the AWH system in title of COP, MHI, and specific energy consumption. The AWH was designed using vapor compression refrigeration system. Parameter measured to the system were refrigerant temperature in suction and discharge line, inlet and outlet pipe wall temperatures at evaporator and condenser, air velocity enter into evaporator, and electrical energy consumption. Instrument used in this research were refrigerant pressure-temperature gauge, K-type digital thermometer, digital fan anemometer, thermo-hygro meter, and kWh meter. Air temperature and RH data were 36,5 oC, 40%, and 19 oC, 42 % for inlet and outlet air stram at evaporator, subsequently. With air velocity 1.5 m/s, the COP of the system was 3.7. Water collected from AWH was 1.1 litres/hour with energy consumption of 1.24 kWh. The AWH could be considered as a water harvester with value of specific energy of 1.13 kWh/litre and MHI of 0,2.
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Amirfakhraei, Amirhossein, Jamshid Khorshidi, and Taleb Zarei. "A thermodynamic modeling of 2-bed adsorption desalination to promote main equipment performance." Journal of Water Reuse and Desalination 11, no. 1 (January 5, 2021): 136–46. http://dx.doi.org/10.2166/wrd.2021.059.
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Abstract Adsorption desalination utilizes the discrete adsorption of the water vapor from the evaporator, and is capable of being discharged to the condenser. This study illuminated an advanced cycle of mass and heat recovery among beds, condensers, and evaporators. Morover, the thermodynamic modeling of adsorption desalination systems (ADS) under different operating conditions was investigated. Furthermore, its effect on the evaporator vapor production and the water vapor adsorption and desorption in the adsorption beds were accounted for. Parenthetically, the mathematical model of ADS thermodynamics was validated with the experimental data. Besides, the advanced ADS modeling was conducted via mass and heat recovery among beds, condensers, and evaporators. In addition to the amount of desalinated water, the time history chart of the equipment applied in the process with and without the thermal and mass recovery is also illustrated. Finally, under such operating conditions, the specific daily water production (SDWP) advanced ADS is 153% higher than conventional ADS.
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Guinn, Gerald R. "Field Test Evaluation of Solar-Heated Evaporators." Journal of Solar Energy Engineering 114, no. 3 (August 1, 1992): 165–70. http://dx.doi.org/10.1115/1.2930000.
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The cost of disposal of liquid industrial waste is of intense concern to all industrial waste generators, but especially so to smaller generators which are penalized by the economy of scale. As a last resort to on-site treatment or recycling, the smaller generator is forced to depend upon commercial waste disposal at costs approaching $6.00 per gallon. The use of solar energy to evaporate water from aqueous wastes is a potentially viable alternative if the contaminants are salts having low volatility. This paper describes a field test conducted with a small solar evaporator installed in a machine shop. A naturally vented, basin-type evaporator was used to evaporate water from a spent plating solution used to anodize aluminum. Measured evaporation data validated performance predictions made earlier using TRNSYS and TMY weather data. The data also indicated that accepted correlation models for predicting performance of solar stills underpredict evaporator performance by about 20 percent.
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Pektezel and Acar. "Energy and Exergy Analysis of Combined Organic Rankine Cycle-Single and Dual Evaporator Vapor Compression Refrigeration Cycle." Applied Sciences 9, no. 23 (November 21, 2019): 5028. http://dx.doi.org/10.3390/app9235028.
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This paper presents energy and exergy analysis of two vapor compression refrigeration cycles powered by organic Rankine cycle. Refrigeration cycle of combined system was designed with single and dual evaporators. R134a, R1234ze(E), R227ea, and R600a fluids were used as working fluids in combined systems. Influences of different parameters such as evaporator, condenser, boiler temperatures, and turbine and compressor isentropic efficiencies on COPsys and ƞex,sys were analyzed. Second law efficiency, degree of thermodynamic perfection, exergy destruction rate, and exergy destruction ratio were detected for each component in systems. R600a was determined as the most efficient working fluid for proposed systems. Both COPsys and ƞex,sys of combined ORC-single evaporator VCR cycle was detected to be higher than the system with dual evaporator.
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Rogié, Brice, Jonas Kjær Jensen, Svenn Ole Kjøller Hansen, and Wiebke Brix Markussen. "Analysis of Cold Air Recirculation in the Evaporators of Large-Scale Air-Source Heat Pumps Using CFD Simulations." Fluids 5, no. 4 (October 21, 2020): 186. http://dx.doi.org/10.3390/fluids5040186.
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The present study investigates cold air recirculation in the evaporators of large-scale air-source heat pumps. A case study considered a 5 MW air-source heat pump producing heat for district heating. The heat pump comprises 20 horizontal evaporators, where each evaporator is equipped with eight fans. The evaporators were implemented in a CFD model, where the influence of the outdoor wind direction on the recirculation was investigated. Firstly, the air recirculation was analysed with no surrounding obstacles. Secondly, the surrounding building and the real ground topology was included in the CFD model, to analyse their influence on the air recirculation. The results show that recirculation occurs for all wind directions, due to the turbulent behaviour of the flow around the evaporators. The results also show that the presence of a building intensifies the recirculation when it is placed directly upstream of the evaporators due to the presence of vortices in the wake of the building. On the other hand, a ground depression helps to reduce the recirculation by having additional energy dissipation due to the sudden change in the ground direction.
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Krapivin, Mkrtchyan, and Rochon. "Hydrological Model for Sustainable Development in the Aral Sea Region." Hydrology 6, no. 4 (October 22, 2019): 91. http://dx.doi.org/10.3390/hydrology6040091.
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Possible scenarios of the Aral Sea crisis solution are discussed, and a new scenario is proposed. Previous scenarios have provided for the transfer of water from Siberian Rivers to Central Asia and the restriction of unsustainable expansion of irrigation in this region. The scenario proposed in this paper is partly based on the use of Caspian water evaporators located on the eastern coast of the Caspian Sea. Engineering realization of this scenario needs only the construction of the drainage system for the runoff of Caspian waters to the natural evaporators, between which Kara-Bogaz-Gol is the functioning evaporator. This paper shows that realization of this scenario allows the rescue of the Aral Sea and normalization of the water balance in Central Asia. Under this, as the simulation modeling results show, there exist different versions of the scenario depending on the area of evaporators and restrictions for the runoff of Amu Darya and Syr Darya waters to the irrigation systems. Calculation results show that the Aral Sea could be restored within 90–240 years depending on the scenario versions. With only Kara-Bogaz-Gol as the evaporator, the Aral Sea cannot be restored within a century. Additionally, if the anthropogenic runoff of river waters was decreased by 10 percent, the Aral Sea would be restored over about 90 years. Possible versions of the recovery scenario are discussed and assessed.
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Usmonov, Nizomjon, Shaxlo Mavjudova, and Adeliya Ivanisova. "Mathematical modeling of heat and mass exchange processes in the evaporative cooler." E3S Web of Conferences 304 (2021): 01012. http://dx.doi.org/10.1051/e3sconf/202130401012.
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This article describes the advantages of the widespread using of the evaporative coolers for cooling recycled wastewater in the air conditioning systems in various industries. The mathematical model of heat and mass transfer processes in the evaporative coolers has been developed. The dependence of the changes in the temperature of the air leaving the evaporator on the irrigation density is considered. When comparing the values obtained by using mathematical expressions and experiments, the resulting difference was 6.7%.
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Zavargo, Zoltan, Aleksandar Jokic, Bojana Prodanic, Jasna Grbic, and Rada Jeftic-Mucibabic. "Performance of falling film plate evaporators in reconstructed multiple-effect evaporation station in sugar factory." Thermal Science 10, no. 4 (2006): 55–61. http://dx.doi.org/10.2298/tsci0604055z.
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General trend of free trade in regional level as well as in the direction of European Union has motivated sugar factories located in Serbia to invest into technologies that are more efficient in order to make their products more competitive at the markets in Europe. The aim of this work was to evaluate effects of falling film plate evaporators on the energy consumption of evaporation plant, as well as to validate performance of this type of evaporators. It was found that this type of evaporator decreased energy requirements and in the same time evaporation process was more effective due to high values of heat transfer coefficients. .
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Hung, Kuo-Shu, Jenn-Chyi Chung, Chung-Che Liu, Jun-Jie Lin, and Chi-Chuan Wang. "A Comparative Study of the Oil-Free Centrifugal Water Chillers with the Flooded or Falling Film Evaporator—A Case Study." Energies 12, no. 13 (July 2, 2019): 2548. http://dx.doi.org/10.3390/en12132548.
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A comparative study regarding the performance of real-scale oil-free centrifugal chillers having the flooded evaporator or falling film evaporator was conducted in this study. The nominal capacity for the test chillers was around 200~230 USRT (US refrigeration ton) (703~809 kW). The compressors of the two chillers were identical and R-134a was used as the working fluid. Both evaporators employed the same enhanced tubes (GEWA-B) to fulfill phase change. Tests were conducted in full, 75%, 50%, and 25% loading. Test results indicate that both chillers contained a comparable system performance with an integrated part-load value of around 8.62~8.63. The overall heat transfer coefficient for the flooded evaporator was appreciably higher (20~40%) than the falling film evaporator. This is because the falling film flowrate was below the threshold value and the heat transfer was dominated by evaporation mode. Yet, the heat transfer performance for the falling film evaporator was further jeopardized due to starvation of the film flowrate (partial dry-out), especially in the middle or bottom of the tube bundle. This phenomenon became even more pronounced at partial loading (25%), whereas the flooded evaporator did not reveal such a performance dip at partial loading.
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Hermes, Christian J. L., Joel Boeng, Diogo L. da Silva, Fernando T. Knabben, and Andrew D. Sommers. "Evaporator Frosting in Refrigerating Appliances: Fundamentals and Applications." Energies 14, no. 18 (September 21, 2021): 5991. http://dx.doi.org/10.3390/en14185991.
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Modern refrigerators are equipped with fan-supplied evaporators often tailor-made to mitigate the impacts of frost accretion, not only in terms of frost blocking, which depletes the cooling capacity and therefore the refrigerator coefficient of performance (COP), but also to allow optimal defrosting, thereby avoiding the undesired consequences of condensate retention and additional thermal loads. Evaporator design for frosting conditions can be done either empirically through trial-and-error approaches or using simulation models suitable to predict the distribution of the frost mass along the finned coil. Albeit the former is mandatory for robustness verification prior to product approval, it has been advocated that the latter speeds up the design process and reduces the costs of the engineering undertaking. Therefore, this article is aimed at summarizing the required foundations for the design of efficient evaporators and defrosting systems with minimized performance impacts due to frosting. The thermodynamics, and the heat and mass transfer principles involved in the frost nucleation, growth, and densification phenomena are presented. The thermophysical properties of frost, such as density and thermal conductivity, are discussed, and their relationship with refrigeration operating conditions are established. A first-principles model is presented to predict the growth of the frost layer on the evaporator surface as a function of geometric and operating conditions. The relation between the microscopic properties of frost and their macroscopic effects on the evaporator thermo-hydraulic performance is established and confirmed with experimental evidence. Furthermore, different defrost strategies are compared, and the concept of optimal defrost is formulated. Finally, the results are used to analyze the efficiency of the defrost operation based on the net cooling capacity of the refrigeration system for different duty cycles and evaporator geometries.
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Mohd Khanafiah, Muhammad Azim, Nur Adilah Sahafudin, and Fauziah Jerai. "Evaporator Performance for Water Refrigerant Adsorption Cooling System." Journal of Mechanical Engineering 19, no. 2 (April 15, 2022): 1–16. http://dx.doi.org/10.24191/jmeche.v19i2.19667.
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Adsorption Cooling System gives an alternative to the commercial vapor compression refrigeration cycles due to their benefits of having a very environmentally friendly and promising energy-saving system. An adsorption cooling system consists of four main components which are thecondenser, evaporator, expansion valve, and adsorption bed for the system to effectively function. One of the factors that affect the efficiency of the system is the performance of the evaporator itself as the system operates at sub-atmospheric pressure and the performance is mediocre when using conventional evaporators. Due to the low-pressure condition, hydrostatic pressure may affect the saturated temperature of the water refrigerant in a flooded type evaporator. Therefore, in this study, the performance of the evaporator was investigated based on the water height variation. The highest heat transfer coefficient and evaporation heat transfer rate are achieved when the water is set at the heat exchanger tube diameter level. Furthermore, 0.1 kg of silica gel adsorbent is used to obtain the maximum of 250 W/kg of Specific Cooling Power when the heat transfer fluid is set to 20 ºC.
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Zhou, Shu Zhang, Rui Kong, Min Qiang Pan, Qiao Xia Yuan, and Ting Bo Hou. "Effects of Microstructure Types on the Evaporation Efficiency of Electrically Heated Micro Evaporator." Advanced Materials Research 655-657 (January 2013): 1123–26. http://dx.doi.org/10.4028/www.scientific.net/amr.655-657.1123.
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In this work, a laminated microstructure-plate electrically heated micro evaporator was proposed. The effects of microstructure types on the evaporation efficiency of electrically heated micro evaporator under different input voltage values and flow rates of water were investigated. It was indicated that the triangular microstructure plate presented the best evaporation efficiency regardless of the change of input voltage and feed flow rate. The nonuniform-distributed microchannel plate presented better evaporation performance than that of uniform-distributed microchannel plate, while the triangular microstructure plate presented higher evaporative performance than that of rectangular microstructure plate.
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Nguyen, Tronghieu, and Thanhtrung Dang. "The Effect of Fin Shape on the Heat Transfer and the Solution Time of a Microchannel Evaporator in a CO2 Air Conditioning System—A Numerical Investigation." Micromachines 13, no. 10 (September 30, 2022): 1648. http://dx.doi.org/10.3390/mi13101648.
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Numerical simulations on the fin shape of a microchannel evaporator in a CO2 air conditioning system were performed at the inlet evaporative temperature of 10 °C and the vapor quality of 0.61. Two types of fin shapes were dealt with: the straight fins and V-fins. The numerical results were verified by the experimental data. For the system under consideration and for the same heat transfer area and the heat transfer coefficient for the air side in the microchannel evaporator, the effect of the fin shape on the heat transfer was not different; however, the solution time and the physical memory for the straight fins were 1.3 and 1.45 times compared with the V-fins, respectively. Therefore, the V-fin shape should be used for numerical simulation to compare it with the straight fin shape. In this study, the evaporation of the refrigerant in the microchannel evaporator took place in four passes. The normal heat flux from the air through the fins and tubes was almost reached at 1550 W/m2 at the evaporative temperature of 10 °C. The results obtained from the experimental data were in good agreement with those obtained from the numerical results, with a deviation of less than 10%.
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Pisal, Prof Mr N. S. "Design and Development of Solar Powered 360degree Automatic Air Cooler." International Journal for Research in Applied Science and Engineering Technology 10, no. 7 (July 31, 2022): 837–40. http://dx.doi.org/10.22214/ijraset.2022.45370.
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Abstract: Evaporative coolers lower the temperature of air using the principle of evaporative cooling, unlike typical air conditioning systems which use vapor-compression refrigeration or absorption refrigerator. Evaporative cooling is the conversion of liquid water into vapor using the thermal energy in the air, resulting in a lower air temperature. The energy needed to evaporate the water is taken from the air in the form of sensible heat, which affects the temperature of the air, and converted into latent heat, the energy present in the water vapor component of the air, whilst the air remains at a constant enthalpy value. Vapor-compression refrigeration uses evaporative cooling, but the evaporated vapor is within a sealed system, and is then compressed ready to evaporate again, using energy to do so. Simple evaporative coolers water is evaporated into the environment, and not recovered. In an interior space cooling unit, the evaporated water is introduced into the space along with the now-cooled air; in an evaporative tower the evaporated water is carried off in the airflow exhaust. To Develop the Energy efficient, environment friendly direct evaporative air conditioning system having low operating cost suitable for hot and dry regions To Manufacture advanced 360-degree Rotating air cooler which rotates and provide air cooling in all directions. It can be used for domestic as well as Industrial applications. The temperature of dry air can be dropped significantly through the phase transition of liquid water to water vapor (evaporation). This can cool air using much less energy than refrigeration. In extremely dry climates, evaporative cooling of air has the added benefit of conditioning the air with more moisture for the comfort of building occupants
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Riadi, Indra, and Dani Puji Utomo. "The Effect of Operating Condition on Low Pressure Steam (LPS) in Sugar Factory by Pinch Analysis." UNISTEK 9, no. 1 (March 24, 2022): 68–82. http://dx.doi.org/10.33592/unistek.v9i1.1786.
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In the present work the sugar plant in Sragen, Central Java, Indonesia has ten evaporators that can be configured to five effect evaporators. The optimization ofenergy demand, finding optimum operating condition of LowPressure Steam (LPS), and choosing the best configuration of multiple effect evaporator (MEE) were performed by pinch analysis. In this paper, LPS at 0.4 kg/cm2.G – 1.1 kg/cm2.G were evaluated. The results show that the optimum operating condition of LPS was at 0.9 kg/cm2.G – 1.1 kg/cm2.G. This optimum operating condition enhances the energy saving by about 30% compared to that of existing plant (0.4 kg/cm2.G). The best performance value that can be achieved were Steam on Cane (SOC) by 43.50% and Steam Economy (SE) by 2.1
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Wadell, Robert, Yogendra K. Joshi, and Andrei G. Fedorov. "Experimental Investigation of Compact Evaporators for Ultralow Temperature Refrigeration of Microprocessors." Journal of Electronic Packaging 129, no. 3 (March 28, 2007): 291–99. http://dx.doi.org/10.1115/1.2753919.
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Microprocessor performance can be significantly improved by lowering the junction temperature, especially down to the deep subambient levels. This provides the strong motivation for the current study, which focuses on the design and thermohydraulic performance evaluation of high heat flux evaporators suitable for interfacing the microprocessor chip with a cascaded R134a∕R508b vapor compression refrigeration system at −80°C. Four compact evaporator designs are examined—a base line slit-flow structure with no microfeatures, straight microchannels, an inline pin fin array, and an alternating pin fin array—all fitting the same size envelope. Pressure drop and heat transfer measurements are reported and discussed to explain the performance of the various evaporator geometries for heat fluxes ranging between 20W∕cm2 and 100W∕cm2.
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Li, Chao-Jen, Jiung-Horng Lin, and Chin-Chia Su. "Heat Transfer in the Evaporators of a Double-Evaporator Refrigerating System." Heat Transfer Engineering 27, no. 8 (September 2006): 16–24. http://dx.doi.org/10.1080/01457630600793947.
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Li, Junying, Sheng Chen, Cuihuan Li, Mengyao Cao, Jiahui Mu, Haq Nawaz, Zhe Ling, and Feng Xu. "Janus Biopolymer Sponge with Porous Structure Based on Water Hyacinth Petiole for Efficient Solar Steam Generation." International Journal of Molecular Sciences 23, no. 16 (August 16, 2022): 9185. http://dx.doi.org/10.3390/ijms23169185.
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Solar-driven steam generation for desalination is a facile, sustainable, and energy-saving approach to produce clean freshwater. However, the complicated fabrication process, high cost, potential environmental impact, and salt crystallization of conventional evaporators limit their large-scale application. Herein, we present a sustainable Janus evaporator based on a biopolymer sponge from the water hyacinth petiole (WHP) for high-performance solar steam generation. The freeze-dried WHP maintained its original porous structure and aligned channels well, and therefore holds the capability for rapid water transport due to strong capillary action. The WHP coated with carbon nanotubes/ethyl cellulose paste on its surface (WHP-C) gains a good photothermal property, thus achieving an efficient solar steam generation with a rate of 1.50 kg m−2 h−1 under 1 sun irradiation. Moreover, the WHP-C after hydrophobic modification by fluorocarbon (WHP-CH) is endowed with high water repellency and exhibits good salt resistance during long-term solar desalination. Additionally, we demonstrate that a stable wet surface that enables efficient water supply and vapor escape is also significant to the successive desalination of a solar evaporator. Our work provides new insights into the high-value utilization of biomass waste, i.e., water hyacinth, and the development of sustainable interfacial solar evaporators for the environmentally friendly production of freshwater.
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Tahir, Furqan, Abdelnasser Mabrouk, Sami G. Al-Ghamdi, Igor Krupa, Tomas Sedlacek, Ahmed Abdala, and Muammer Koc. "Sustainability Assessment and Techno-Economic Analysis of Thermally Enhanced Polymer Tube for Multi-Effect Distillation (MED) Technology." Polymers 13, no. 5 (February 24, 2021): 681. http://dx.doi.org/10.3390/polym13050681.
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Metal-alloys tubes are used in the falling-film evaporator of the multi-effect distillation (MED) that is the dominant and efficient thermal seawater desalination process. However, the harsh seawater environment (high salinity and high temperature) causes scale precipitation and corrosion of MED evaporators’ metal tubes, presenting a serious technical challenge to the process. Therefore, the metal/metal alloys used as the material of the MED evaporators’ tubes are expensive and require high energy and costly tube fabrication process. On the other hand, polymers are low-cost, easy to fabricate into tubes, and highly corrosion-resistant, but have low thermal conductivity. Nevertheless, thermally conductive fillers can enhance the thermal conductivity of polymers. In this article, we carried out a feasibility-study-based techno-economic and socioeconomic analysis, as well as a life-cycle assessment (LCA), of a conventional MED desalination plant that uses titanium tubes and a plant that used thermally enhanced polymer composites (i.e., polyethylene (PE)-expanded graphite (EG) composite) as the tubes’ material. Two different polymer composites containing 30% and 40% filler (expanded graphite/graphene) are considered. Our results indicate that the MED plant based on polymer composite tubes has favored economic and carbon emission metrics with the potential to reduce the cost of the MED evaporator (shell and tubes) by 40% below the cost of the titanium evaporator. Moreover, the equivalent carbon emissions associated with the composite polymer tubes’ evaporator is 35% lower than titanium tubes. On the other hand, the ozone depletion, acidification, and fossil fuel depletion for the polymer composite tubes are comparable with that of the titanium tubes. The recycling of thermally enhanced polymers is not considered in this LCA analysis; however, after the end of life, reusing the polymer material into other products would lower the overall environmental impacts. Moreover, the polymer composite tubes can be produced locally, which will not only reduce the environmental impacts due to transportation but also create jobs for local manufacturing.
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Ozturk, Recep, and Ahmet Dursun Alkan. "Determination of Optimum Heat Transfer Area for Vacuum Evaporators in Ships." Marine Technology and SNAME News 41, no. 01 (January 1, 2004): 17–21. http://dx.doi.org/10.5957/mt1.2004.41.1.17.
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In ships, utility water can be produced from seawater through a vacuum evaporator instead of supplying from ports, and this solution will certainly allow extra load capacity for ships. In this application, the size of vacuum evaporators and their heat transfer areas are significant factors in terms of investment costs and the volume or weight capacity, which for ships are particularly important parameters. In the present research, the change of heat transfer areas of vacuum evaporators that are used to produce utility water was analyzed with respect to design parameters and the results from the thermodynamic analysis were evaluated to define the optimum heat transfer area. Because an analytical method has been employed in the definition of the optimum heat transfer area, the influence of design parameters on the evaporatorsize can be identified easily.
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Ebuehi, Osaretin N. I., Olanrewaju M. Daramola, and Aminat I. Idowu. "The Chemical Engineering Design of a Commercial Citrus Evaporator for the Production of 6,539.86 kg/hr Orange Juice Concentrate in Lagos, Nigeria, West Africa." European Journal of Engineering and Technology Research 7, no. 5 (October 12, 2022): 50–59. http://dx.doi.org/10.24018/ejeng.2022.7.5.2860.
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Chemical engineers are high in importunity by industries in a wide range of sectors for the following impetus: Based on nominally defined problem statements, such as a client need or a set of experimental ramifications, chemical engineers can devise and gain a profound understanding of fundamental physical science relevant to the enigma, and harness this apprehension to excogitate a comprehensive action plan and a set of detailed specifications that, if implemented, will lead to forecasted financial dividends. In this treatise, as chemical engineers, apply our scientific and mathematical knowledge, specifically chemistry, applied mathematics, and engineering concepts, to translate experimental or conceptual ideas into value-added products in a lucrative, safe (environmentally friendly), and industry-leading manner. Citrus sinensis is the scientific name for orange, a savory and aromatic fruit from the Rutaceae family. The annual global citrus production increased dramatically over the last few decades, from around 30 million metric tonnes in the late 1960s to an estimated total of more than 105 million metric tonnes from 2000 to 2004, with oranges accounting for more than half of total global citrus production. Evaporation is a principle habituated in the processing industry to concentrate aqueous liquid streams by vaporizing the quantity of water content in a solution. The curtailment of energy consumption for evaporation reckoned on multitudinous components, such as evaporation capacity, number of effects, operation efficiency, and annual operation hours. We emphasized burgeoning efficient strategies to curtail the energy consumption of evaporators and alluded that monitoring the rate of energy dissipation guarantee the sustainability of an industrial enterprise. We betokened the heat transfer area was the indispensable criterion in the design of an evaporator and delineated correlations for estimating the size of the tube bundle. Ideally, a well-designed evaporator should be able to transfer heat adeptly at a high flow rate, have the minimum valuation of installation, operation, and maintenance, be able to bifurcate vapors from liquid concentrates, meet the conditions required by the product under treatment, produce a product of a quality required, and, if possible, be energy efficient. The peculiar grade of evaporator adopted was the 5-effect, 8-stage Thermally Accelerated Short Time Evaporator. We embraced the genre of evaporators after investigating their benefits relative to other evaporators used in food processing. In addition, it is fundamental to institute governance to identify benchmarks for optimal distribution based on results obtained by all segments of the production chains and orange juice exporters. This input will benefit the collective national interest and is pivotal for the orange juice industry.
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Rulev, A. V., and A. A. Sidorin. "Study of Heat Transfer Rate in Electric Evaporators of Liquefied Petroleum Gas Using Electrothermal Modeling." Journal of Physics: Conference Series 2096, no. 1 (November 1, 2021): 012067. http://dx.doi.org/10.1088/1742-6596/2096/1/012067.
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Abstract In modern domestic and foreign experience of gas power supply to houses and industrial facilities located remotely from the main power station, decentralized gas power supply systems fed with propane-butane mixtures of liquefied petroleum gases from tanks are increasingly used. When using liquefied petroleum gases as the main energy carrier in gas tank systems, they are evaporated artificially in evaporators with an intermediate solid-state or liquid heat transfer agent, under conditions of its natural convection. The main operational characteristic of industrial tube evaporators of propane-butane mixtures of liquefied petroleum gases used for gas power supply from tank installations of housing and communal, industrial and industrial facilities that are remote from the main power supply stations is evaporation capacity. The evaporation capacity of industrial tube evaporators of propane-butane mixtures with a solid-state intermediate heat transfer medium is determined by the heat input from the tubular electric heaters through the aluminum casting layer. Therefore, the study of heat transfer in the solid–state intermediate heat transfer medium-evaporation coil system is the most important prerequisite for the effective operation of industrial tube evaporators of propane-butane mixtures and requires detailed research. To solve the problem of determining the heat transfer resistance between the layers of aluminum casting in contact with the surface of the tubular electric heaters group and the outer evaporation coil surface studies were performed on an electrical model. The average value of the total error of the results of experimental studies on electrothermal modeling is 3.7 %, with a confidence probability of 95 %. Recommendations are given for reducing the thickness of the layers in clear from the lower coil of the evaporative tube coil to the lower generatrix of the solid-state aluminum mass and the upper coil of the evaporative tube coil to the upper generatrix of the solid-state aluminum mass.
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Zabet, Ion, and Gratiela Maria Tarlea. "Mathematical Simulation of the Thermodynamic Processes Associated with the Vapour-Injected Scroll Compressor." E3S Web of Conferences 111 (2019): 06057. http://dx.doi.org/10.1051/e3sconf/201911106057.
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Both the major energetic crisis and the global warming, which influence the worldwide economy and the future of the society, determine the development of energetic and ecological performances of both the refrigeration equipment and air conditioning systems. Thus, there is a worldwide supported effort made in order to decrease the carbon dioxide emissions resulted from the burning of fossil fuels and the other greenhouse effect gas emissions. This article presents a refrigeration system design model using a vapour injection scroll compressor and tube in tube evaporators working with refrigerant R407C. The refrigerant circuit comprises of a main evaporator, a secondary evaporator (for the injection process), scroll compressor, condenser and five expansion valves. Furthermore it uses R407C as refrigerant. The secondary refrigerant for both the main and the secondary evaporator is a 50% concentration solution of propylene-glycol and water. Secondary circuit comprises of a pump, an electric boiler, an expansion vessel and a by-pass circuit made of many stop valves. The condenser is cooled with mains water.
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Pang, Liping, Desheng Ma, Yadan Zhang, and Xiaodong Yang. "Experimental and Numerical Investigation on Heat Transfer Performance of Water Evaporators with Different Channels and Fin Structures in a Sub-Atmosphere Environment." Aerospace 9, no. 11 (November 7, 2022): 697. http://dx.doi.org/10.3390/aerospace9110697.
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A water evaporator is a phase change heat exchanger, as a heat sink, especially for high-speed flight vehicles. It is composed of internal channels for convective cooling and external fins for boiling. In this paper, six water evaporators, Hex0–Hex5, are designed with five different internal channels and two different external fins. The VOF simulation models are built to investigate their boiling heat transfer performances in a sub-atmospheric environment. Experimental studies were carried out to verify the accuracy of the numerical model of water evaporator. The simulation results show that the structures of the internal channel and external fin both have an impact on the heat transfer performance. For the internal channels, their height change has much more obvious effect than their structural continuity. For the external fins, the increase of the fin bulge structure helps to improve the heat transfer performance. For the aircraft, the optimal design structure of water evaporator is Hex4 and its heat transfer performance can be improved by 13.31% compared with Hex0.
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Zhou, Xiaojiao, Ningyao Tao, Wen Jin, Xingyuan Wang, Tuqiao Zhang, and Miaomiao Ye. "Inhibition of Phenol from Entering into Condensed Freshwater by Activated Persulfate during Solar-Driven Seawater Desalination." Molecules 27, no. 21 (October 23, 2022): 7160. http://dx.doi.org/10.3390/molecules27217160.
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Recently, solar-driven seawater desalination has received extensive attention since it can obtain considerable freshwater by accelerating water evaporation at the air–water interface through solar evaporators. However, the high air–water interface temperature can cause volatile organic compounds (VOCs) to enter condensed freshwater and result in water quality safety risk. In this work, an antioxidative solar evaporator, which was composed of MoS2 as the photothermal material, expandable polyethylene (EPE) foam as the insulation material, polytetrafluoroethylene (PTFE) plate as the corrosion resistant material, and fiberglass membrane (FB) as the seawater delivery material, was fabricated for the first time. The activated persulfate (PS) methods, including peroxymonosulfate (PMS) and peroxodisulfate (PDS), were applied to inhibit phenol from entering condensed freshwater during desalination. The distillation concentration ratio of phenol (RD) was reduced from 76.5% to 0% with the addition of sufficient PMS or PDS, which means that there was no phenol in condensed freshwater. It was found that the Cl− is the main factor in activating PMS, while for PDS, light, and heat are the dominant. Compared with PDS, PMS can make full utilization of the light, heat, Cl− at the evaporator’s surface, resulting in more effective inhibition of the phenol from entering condensed freshwater. Finally, though phenol was efficiently removed by the addition of PMS or PDS, the problem of the formation of the halogenated distillation by-products in condensed freshwater should be given more attention in the future.
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Khaleel, Wissam H., Abdul Hadi N. Khalifa, and Hilal Tareq Abdulazeez. "Performance Study of Solar Adsorption Refrigeration System Using Activated Carbon - Methanol." Al-Nahrain Journal for Engineering Sciences 21, no. 4 (December 21, 2018): 523–31. http://dx.doi.org/10.29194/njes.21040523.
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The depleting of the conventional sources of energy and the excess use of HCF components lead to the need for new techniques both for conservation of energy sources for the future and for decreasing the its harmful effects on the environment. This study investigated the adsorption capabilities of activated carbon. The adsorption of methanol on this substance was tested for their application in the adsorption refrigeration system based on solar energy.
Adsorption refrigeration system has been designed and manufactured with the energy source being solar energy. Methanol/activated carbon pairs have been used in experiments. The present work focused on the performance of the adsorption refrigeration system considering the temperature attained in the evaporator and the cooled spaced cabinet. The amounts of activated carbon used was (8 kg), while the amount of methanol were (1, 1.25, and 1.5) kg. The experiments were done in different days of the year. The amount of adsorption of methanol (as a result of decreasing the evaporator and cooled spaced temperature) was found to depend on the generator pressure and its increase as the primary generator pressure decreases. The best mass of methanol used was (1 kg) which give the lowest temperature obtained at the evaporative surface was ( 3.4 oC ) at the day ( 4/4/2017 ). The results shown that even in cloudy days there is a benefit from using such a system because the temperature attained is enough to start the adsorption process. The lowest temperature obtained at the evaporative surface was (3.4 oC) at the day (4/4/2017) for methanol mass of (1 kg) at an opening time of the valve between the evaporator and the generator (9:30am). The increase of methanol amount used in the experiment led to a good decrease in temperature attained in cooled spaced, but this is related to the time of connecting the evaporator and generator.
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Oliveira, R. N., R. V. M. Reis, R. N. N. Koury, and L. Machado. "TRANSIENT MODEL OF A STATIC EVAPORATOR FOR AN AIR-WATER HEAT PUMP." Revista de Engenharia Térmica 10, no. 1-2 (December 31, 2011): 07. http://dx.doi.org/10.5380/reterm.v10i1-2.61944.
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The increasing demand of electric energy in Brazil, allied to the great consumption in rush hour, has stimulated the study of water heating systems that substitute the electric shower. One of these equipments, the solar collector, is the most viable, with the best cost-benefits relation, because Brazil is a tropical country. A heat pump can be used as a support to solar collectors in places where the climatic conditions and/or the lack of available area of solar collection limit the use of the system. One way to improve this heat pump would be the substitution of its conventional evaporator for a static evaporator. This evaporator is constituted of a metallic plate with conformed canals, inside of which the coil is fixed through which the refrigerator cooling of the heat pump flows. The objective of this paper is the development of a mathematical model in transient regimen to simulate the static evaporator operation of an air-water heat pump. Some simulations had been carried through, that had allowed testing geometric parameters of the system, materials for the pipes and plates and different weather conditions. These computational tests had indicated that the model represents a good tool to project static evaporators.
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Kapilan, N., M. Manjunath Gowda, and H. N. Manjunath. "Computational Fluid Dynamics Analysis of an Evaporative Cooling System." Strojnícky casopis – Journal of Mechanical Engineering 66, no. 2 (November 1, 2016): 117–24. http://dx.doi.org/10.1515/scjme-2016-0026.
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Abstract The use of chlorofluorocarbon based refrigerants in the air-conditioning system increases the global warming and causes the climate change. The climate change is expected to present a number of challenges for the built environment and an evaporative cooling system is one of the simplest and environmentally friendly cooling system. The evaporative cooling system is most widely used in summer and in rural and urban areas of India for human comfort. In evaporative cooling system, the addition of water into air reduces the temperature of the air as the energy needed to evaporate the water is taken from the air. Computational fluid dynamics is a numerical analysis and was used to analyse the evaporative cooling system. The CFD results are matches with the experimental results.
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Ilsters, Andrievs, and Imants Ziemelis. "Research On Decrease Of Outside Air Heat Pump Passive Evaporators Ice-Cover." Environment. Technology. Resources. Proceedings of the International Scientific and Practical Conference 1 (August 5, 2015): 197. http://dx.doi.org/10.17770/etr2011vol1.895.
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Two years (2009-2010) experience of the experimental use of alternative energy sources in technological processes of agriculture is analyzed. Water was heated by an outside air heat pump with passive evaporators, and used for new born piglets resting place floor heating. Experimental data were obtained by the reckoning consumption of electric energy for the operation of the heat pump’s compressor and electric heater, and by a heat meter registering the consumed heat energy. The obtained data show that the outside air heat pump with passive evaporators is working successfully during summer months, when the coefficient of performance (COP) of the heat pump exceeds 3.5. When the outside temperature decreases under +10˚C, the heat pump evaporators become covered with hoarfrost and ice. The value of the COP and produced amount of heat energy reduce, and the electric heater often switches on. During the experimental research one of the heat pump evaporators was supplied with a ventilator, air flow from which was washing the surface of the evaporator’s plates. So the satisfactory operation of the heat pump was provided till December 10, 2009 and November 25, 2010.
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Hussain, Shafqat, Abdulrahim Kalendar, Muhammad Zeeshan Rafique, and Patrick Oosthuizen. "Numerical investigations of solar-assisted hybrid desiccant evaporative cooling system for hot and humid climate." Advances in Mechanical Engineering 12, no. 6 (June 2020): 168781402093499. http://dx.doi.org/10.1177/1687814020934999.
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This article presents numerical investigations of the solar-assisted hybrid desiccant evaporative cooling system integrated with standard air collectors for applications under the hot and humid climatic conditions of Kuwait city. The objective is to introduce the energy-efficient and carbon-free solar-assisted hybrid desiccant evaporative cooling system to alleviate the principal problems of electricity consumption and carbon emissions resulting from the use of the conventional vapor-compression cooling systems. In the normal building, during cooling load operation, the solar-assisted hybrid desiccant evaporative cooling system can cope with the cooling load particularly sensible by evaporative cooling and latent through desiccant dehumidification. The outcomes of this work indicate that solar-assisted hybrid desiccant evaporative cooling device integrated with air collectors is capable of providing average coefficient of performance of 0.85 and has the potential to provide cooling with energy saving when compared with conventional vapor-compression refrigeration systems. It was concluded that under the intense outdoor environmental conditions (ambient air at greater than 45°C and 60% relative humidity), the delivered supply air from the evaporative cooling was nearly at 27°C and 65% relative humidity. To solve this problem, the system was assisted with conventional cooling coil (evaporator of heat pump) to supply air at comfortable conditions in the conditioned space.
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Usmonov, N., Sh Sanayev, and Z. Yusupov. "CALCULATION OF TEMPERATURE OF ROUTINE WATER COOLED IN IRRIGATED LAYERS." Technical science and innovation 2019, no. 3 (September 18, 2019): 249–55. http://dx.doi.org/10.51346/tstu-01.19.3.-77-0036.
Full textAbstract:
The article describes the developed mathematical model, algorithm and program for calculating the process of cooling the water leaving the evaporative cooler and the final temperature of humid air. The compilation of a mathematical model is based on the analysis of literature data. Practically at all industrial enterprises, technological equipment is cooled by means of circulating water supply systems equipped with evaporative coolers. The article made a choice of a cooling system for air conditioning systems of residential premises. The developed basic design scheme of the evaporative water and air cooler with the irrigated layer is presented, as well as the estimated thermal and material balance. One of the main elements of these devices is a heat-mass transfer nozzle - sprinkler. This article presents the results of mathematical modeling of processes occurring in the volume of the sprinkler evaporator chamber, Raschig rings composed of vertical polymeric materials. Expressions are obtained for determining the values of air temperature based on the calculation of thermal modeling of the process of cooling circulating water in evaporative coolers of the type in question.