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Статті в журналах з теми "Activated carbon; methanol; adsorption refrigeration"
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Ji, A. Min, Tian Tian, and Bo Ning Tang. "Study on Solar Energy for Pre-Cooling Technology of Fruit and Vegetable." Applied Mechanics and Materials 700 (December 2014): 37–41. http://dx.doi.org/10.4028/www.scientific.net/amm.700.37.
Повний текст джерелаАнотація:
This paper discusses the importance of per-cooling vegetable and fruit, establishes a mathematical model of the solar adsorption refrigeration system collector bed. It applies activated carbon - methanol as working pairs, takes solar vacuum tube－water cooled collector bed for refrigerating, adsorption temperature and adsorption rate versus time are calculated , draw the corresponding curve figure. Analyses solar adsorption refrigeration system performance and puts forward the improvement direction.
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Wang, R. Z., J. P. Jia, Y. H. Zhu, Y. Teng, J. Y. Wu, J. Cheng, and Q. B. Wang. "Study on a New Solid Absorption Refrigeration Pair: Active Carbon Fiber—Methanol." Journal of Solar Energy Engineering 119, no. 3 (August 1, 1997): 214–18. http://dx.doi.org/10.1115/1.2888021.
Повний текст джерелаАнотація:
Our experiments show that active carbon fiber (ACF) might be a good substitute for activated carbon (AC) as the refrigeration capacity Qf and adsorption time of ACF are three times more and 1/5 ∼ 1/10 of those of normal activated carbon (AC), respectively. The COP for ACF-methanol could be 10 percent ∼ 20 percent higher than that of AC-methanol. Thus ACF-methanol might be a good adsorption refrigeration pair for constructing adsorption refrigerators, especially those for household applications.
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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.
Повний текст джерелаАнотація:
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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Sur, Anirban, Randip Das, and Ramesh Sah. "Influence of initial bed temperature on bed performance of an adsorption refrigeration system." Thermal Science 22, no. 6 Part A (2018): 2583–95. http://dx.doi.org/10.2298/tsci160108254s.
Повний текст джерелаАнотація:
The study deals with the complete dynamic analysis (numerical and practical) of an existing adsorption refrigeration system. The adsorption refrigeration setup is available at Indian School of Mines (Dhanbad, India), Mechanical engineering department. The system operates with activated carbon (as an adsorbent) and methanol (as refrigerant).Numerical model is established base on energy equation of the heat transfer fluid (water) and transient heat and mass transfer equations of the adsorbent bed. The input temperature of heat source is 90?C, which is very low compared to other low-grade energy input refrigeration system. The thermo-physical properties of an adsorptive cooling system (using activated carbon?methanol pair) are considered in this model. In this analysis influence of initial bed temperature (T1) on the bed performances are analysed mathematically and experimentally. The simulation and practical results of this system show that the cycle time decreases with increase in initial bed temperature and the minimum cycle time is 10.74 hours (884 minutes for practical cycle) for initial bed temperature of 40?C. Maximum system COP and specific cooling capacity are 0.436 and 94.63 kJ/kg of adsorbent under a condenser and evaporator temperatures of 35?C and 5?C, respectively. This analysis will help to make a comparison between simulated and experimental results of a granular bed adsorption refrigeration system and also to meet positive cooling needs in off-grid electricity regions.
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Shabir, Faizan, Muhammad Sultan, Yasir Niaz, Muhammad Usman, Sobhy M. Ibrahim, Yongqiang Feng, Bukke Kiran Naik, Abdul Nasir, and Imran Ali. "Steady-State Investigation of Carbon-Based Adsorbent–Adsorbate Pairs for Heat Transformation Application." Sustainability 12, no. 17 (August 28, 2020): 7040. http://dx.doi.org/10.3390/su12177040.
Повний текст джерелаАнотація:
In this study, the ideal adsorption cycle behavior of eight activated carbon and refrigerant pairs is evaluated. The selected pairs are KOH6-PR/ethanol, WPT-AC/ethanol, Maxsorb-III/methanol, Maxsorb-III/CO2, Maxsorb-III/n-butane, Maxsorb-III/R-134a, SAC-2/R32 and Maxsorb-III/R507a. The following cooling performance parameters are evaluated for all pairs: specific cooling energy (SCE), concentration difference (ΔW) and coefficient of performance (COP) of ideal adsorption cooling and refrigeration cycles. The evaporator temperatures for the applications of adsorption cooling and refrigeration are selected as 7 and −5 °C, respectively. It is found that the Maxsorb-III/methanol pair has shown the highest specific cooling energy and coefficient of performance in a wide range of desorption temperatures; i.e., for the adsorption cooling cycle it has SCE and COP of 639.83 kJ/kg and 0.803, respectively, with desorption temperatures of 80 °C. The KOH6-PR/ethanol and the WPT-AC/ethanol pairs also give good performances comparable to that of the Maxsorb-III/methanol pair. However, the SAC-2/R32 pair possesses a higher concentration difference than the Maxsorb-III/methanol, KOH6-PR/ethanol and WPT-AC/ethanol pairs but shows a lower performance. This is due to the lower isosteric heat of adsorption of SAC-2/R32 compared to these pairs. It is found that Maxsorb-III/methanol, KOH6-PR/ethanol and WPT-AC/ethanol are the most promising pairs for application in designing adsorption cooling and refrigeration systems.
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Saravanan, N., and M. Edwin. "Optimization and experimental analysis of a solar powered adsorption refrigeration system using selective adsorbent/adsorbate pairs." Journal of Renewable and Sustainable Energy 14, no. 2 (March 2022): 023702. http://dx.doi.org/10.1063/5.0076645.
Повний текст джерелаАнотація:
Adsorption-based cooling system is a cost-effective method of heat conversion. It has the potential to dramatically enhance energy efficiency while also lowering pollutant levels. For this purpose, a solar-powered vapor adsorption refrigeration system (VAdRS) using activated carbon–methanol and zeolite–water as the working pair has been designed and experimentally evaluated. The aim of this experiment was to evaluate the coefficient of performance (COP) and specific cooling power (SCP) of a solar cooling unit by utilizing the optimum minimum and maximum mass concentration ratios. The novel solar-assisted adsorption refrigeration system optimization technique is used in this research to evaluate the optimal performance of the solar-powered VAdRS under various operating scenarios. The experiment was conducted at the optimum minimum and maximum mass concentration ratios of 0.1 and 0.2, respectively. The experimental results show that the activated carbon–methanol adsorption system produces a higher COP value than the zeolite–water adsorption system of 0.49–0.64 and 0.64–0.67 at constant evaporator and condenser temperature, respectively. It also showed that the higher SCP value was revealed in the zeolite–water-based adsorption cooling system as 207.5–217.4 kJ/kg. It was revealed that AC–methanol could be used to operate better in low-generating-temperature conditions. On the other hand, the zeolite–water adsorption system can be used at higher generating temperatures.
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Sur, Anirban, and Randip K. Das. "Numerical Modeling and Thermal Analysis of an Adsorption Refrigeration System." International Journal of Air-Conditioning and Refrigeration 23, no. 04 (December 2015): 1550033. http://dx.doi.org/10.1142/s2010132515500339.
Повний текст джерелаАнотація:
The aim of this paper is to develop a complete, precise and simple numerical model based on the thermophysical properties of an adsorptive cooling system (using activated carbon–methanol pair), analyze and discuss the heat and mass transfer processes and identify the parameters which influence the system performance. In the design of adsorption refrigeration system, the characteristics of both adsorbate–adsorbent pairs and system operating conditions are very important. So in this model, different thermophysical properties of working pair such as, specific heat, density, isosteric heat of adsorption and desorption, and different temperatures of the system are considered. A simulation code, written in FORTRAN, is carried out. The performance of the system is assessed in terms of refrigeration effect and coefficient of performance (COP).
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Soni, Palash, Sruthi Lolalis, Bidyut Mazumdar, Shubhankar Bhowmick, and Vivek Kumar Gaba. "Performance Analysis of an Adsorption Refrigeration System Working on Activated Carbon/Methanol Pair Using Finned Tube Type Adsorber Bed." International Journal of Heat and Technology 39, no. 4 (August 31, 2021): 1335–42. http://dx.doi.org/10.18280/ijht.390433.
Повний текст джерелаАнотація:
Adsorption refrigeration, being a unique and eco-friendly technology, has gained popularity over conventional refrigeration systems. The present study is aimed at developing an annular finned tube adsorber model which serves as a thermal compressor in adsorption refrigeration systems. The mathematical model is addressed numerically using finite difference discretization method and explicit scheme was used for the solution. The generalized model has been simulated for activated carbon–methanol working pair. The system has an optimum cycle time of 1800s. It was found to have a highest refrigeration capacity of 260.66 kJ/kg at a regeneration temperature of 393 K and evaporator temperature of 283 K. The highest COP (Coefficient of Performance) achieved by the system is 0.3706 at a regeneration temperature of 353 K and evaporator temperature of 283 K. A highest SCP (Specific Cooling Power) of 144.8 W/kg was obtained at an evaporator temperature of 283 K and regeneration temperature of 393 K.
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Hassan, H. Z. "Energy Analysis and Performance Evaluation of the Adsorption Refrigeration System." ISRN Mechanical Engineering 2013 (January 3, 2013): 1–14. http://dx.doi.org/10.1155/2013/704340.
Повний текст джерелаАнотація:
A complete steady state thermodynamic differential analysis is developed for the adsorption-based refrigeration systems. The introduced thermodynamic model accurately represents the behaviour of adsorption cooling systems, based on a precise, reasonable, and clear fundamental approach. Based on the energy conservation principle, all components and processes in the system are analyzed. The dynamics of adsorption is expressed by the Dubinin-Astakhov adsorption equilibrium model. All types of energy interactions are evaluated in order to determine the theoretical performance and the operating parameters of the system. Moreover, the actual thermodynamic properties of the refrigerant are considered in developing the model. The case studied is an ice maker which uses activated carbon-methanol as the working pair.
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Grzebielec, Andrzej, Artur Rusowicz, and Rafał Laskowski. "Experimental Study On Thermal Wave Type Adsorption Refrigeration System Working On A Pair Of Activated Carbon And Methanol." Chemical and Process Engineering 36, no. 4 (December 1, 2015): 395–404. http://dx.doi.org/10.1515/cpe-2015-0028.
Повний текст джерелаАнотація:
Abstract The aim of the study was to examine the efficiency of the thermal wave type adsorption refrigerating equipment working on a pair of activated carbon and methanol. Adsorption units can work in trigeneration systems and in applications driven by waste heat. They can be built also as a part of hybrid sorption-compressor systems, and they are very popular in solar refrigeration systems and energy storage units. The device examined in this study operates in a special mode called thermal wave. This mode allows to achieve higher efficiency rates than the normal mode of operation, as a significant contributor to transport heat from one to the other adsorber. To carry out the experiment a test bench was built, consisting of two cylindrical adsorbers filled with activated carbon, condenser, evaporator, oil heater and two oil coolers. Thermal oil circulation was responsible for providing and receiving heat from adsorbers. In order to perform the correct action a special control algorithm device was developed and implemented to keep the temperature in the evaporator at a preset level. The experimental results show the operating parameters changes in both adsorbers. Obtained COP (coefficient of performance) for the cycle was 0.13.
Дисертації з теми "Activated carbon; methanol; adsorption refrigeration"
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You, Ying 1962. "A solar adsorption refrigeration system operating at near atmospheric pressure." Monash University, Gippsland School of Engineering, 2001. http://arrow.monash.edu.au/hdl/1959.1/8740.
Повний текст джерела
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Karki, Bipin. "Experimental and Life Cycle Analysis of a Solar Thermal Adsorption Refrigeration (STAR) Using Ethanol - Activated Carbon." University of Dayton / OhioLINK, 2018. http://rave.ohiolink.edu/etdc/view?acc_num=dayton1524583058600568.
Повний текст джерела
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Raymond, Alexander William. "Investigation of microparticle to system level phenomena in thermally activated adsorption heat pumps." Thesis, Georgia Institute of Technology, 2010. http://hdl.handle.net/1853/34682.
Повний текст джерелаАнотація:
Heat actuated adsorption heat pumps offer the opportunity to improve overall energy efficiency in waste heat applications by eliminating shaft work requirements accompanying vapor compression cycles. The coefficient of performance (COP) in adsorption heat pumps is generally low. The objective of this thesis is to model the adsorption system to gain critical insight into how its performance can be improved. Because adsorption heat pumps are intermittent devices, which induce cooling by adsorbing refrigerant in a sorption bed heat/mass exchanger, transient models must be used to predict performance. In this thesis, such models are developed at the adsorbent particle level, heat/mass exchanger component level and system level.
Adsorption heat pump modeling is a coupled heat and mass transfer problem. Intra-particle mass transfer resistance and sorption bed heat transfer resistance are shown to be significant, but for very fine particle sizes, inter-particle resistance may also be important. The diameter of the adsorbent particle in a packed bed is optimized to balance inter- and intra-particle resistances and improve sorption rate. In the literature, the linear driving force (LDF) approximation for intra-particle mass transfer is commonly used in place of the Fickian diffusion equation to reduce computation time; however, it is shown that the error in uptake prediction associated with the LDF depends on the working pair, half-cycle time, adsorbent particle radius, and operating temperatures at hand.
Different methods for enhancing sorption bed heat/mass transfer have been proposed in the literature including the use of binders, adsorbent compacting, and complex extended surface geometries. To maintain high reliability, the simple, robust annular-finned-tube geometry with packed adsorbent is specified in this work. The effects of tube diameter, fin pitch and fin height on thermal conductance, metal/adsorbent mass ratio and COP are studied. As one might expect, many closely spaced fins, or high fin density, yields high thermal conductance; however, it is found that the increased inert metal mass associated with the high fin density diminishes COP. It is also found that thin adsorbent layers with low effective conduction resistance lead to high thermal conductance. As adsorbent layer thickness decreases, the relative importance of tube-side convective resistance rises, so mini-channel sized tubes are used. After selecting the proper tube geometry, an overall thermal conductance is calculated for use in a lumped-parameter sorption bed simulation. To evaluate the accuracy of the lumped-parameter approach, a distributed parameter sorption bed simulation is developed for comparison. Using the finite difference method, the distributed parameter model is used to track temperature and refrigerant distributions in the finned tube and adsorbent layer. The distributed-parameter tube model is shown to be in agreement with the lumped-parameter model, thus independently verifying the overall UA calculation and the lumped-parameter sorption bed model.
After evaluating the accuracy of the lumped-parameter model, it is used to develop a system-level heat pump simulation. This simulation is used to investigate a non-recuperative two-bed heat pump containing activated carbon fiber-ethanol and silica gel-water working pairs. The two-bed configuration is investigated because it yields a desirable compromise between the number of components (heat exchangers, pumps, valves, etc.) and steady cooling rate. For non-recuperative two-bed adsorption heat pumps, the average COP prediction in the literature is 0.39 for experiments and 0.44 for models. It is important to improve the COP in mobile waste heat applications because without high COP, the available waste heat during startup or idle may be insufficient to deliver the desired cooling duty. In this thesis, a COP of 0.53 is predicted for the non-recuperative, silica gel-water chiller. If thermal energy recovery is incorporated into the cycle, a COP as high as 0.64 is predicted for a 90, 35 and 7.0°C source, ambient and average evaporator temperature, respectively. The improvement in COP over heat pumps appearing in the literature is attributed to the adsorbent particle size optimization and careful selection of sorption bed heat exchanger geometry.
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Douss, Néjib. "Etude experimentale de cycles a cascades a adsorption solide." Paris 7, 1988. http://www.theses.fr/1988PA077052.
Повний текст джерелаАнотація:
Etude experimentale et simulation dynamique de systemes de pompe a chaleur a adsorption solide. Les systemes methanol-charbon actif et eau-zeolite sont etudies. Les conditions de temperature des composants (adsorbeur, condenseur et evaporateur) doivent etre homogenes pour la simulation. On considere les cycles intermittents (simple effet), a double effet et a triple effet (cycle a cascades). Determination d'un coefficient de performance pour la production du froid
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ABDALLAH, KHODR. "Contribution experimentale a l'etude de la cinetique d'adsorption de gaz." Paris, ENSAM, 1989. http://www.theses.fr/1989ENAM0003.
Повний текст джерелаАнотація:
Une nouvelle technique experimentale a ete mise au point pour etudier la cinetique d'adsorption due aux transferts de masse et de chaleur. Application a l'adsorption du methanol sur la zeolite x et le charbon actif
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Zhao, Yongling. "Study of activated carbon/methanol adsorption refrigeration tube and system integration." Thesis, 2011. http://hdl.handle.net/2440/66346.
Повний текст джерелаАнотація:
Solid adsorption refrigeration systems are attracting much research interest because they have numerous advantages, such as using low grade thermal energy and being environment friendly. In recent decades many efforts have been put into developing various prototypes. The adsorption refrigeration tube (ART) is one such development. Through better system integration, a module consisting of a number of individually working ARTs can achieve significant refrigeration capacity, which may solve the vacuum leaking problem that besets large adsorption systems. In order to propose a feasible ART, this thesis undertakes a study of adsorptive properties of three types of activated carbon/methanol working pairs and modelling of the adsorption refrigeration cycle. In this examination of adsorptive properties, three activated carbon samples, Calgon 207C, 207EA and WS-480, were used to test and determine their pressure-temperature-concentration (P−T−x) relationship with methanol as the adsorbate. Based on the experimental data, three adsorption state equations, Langmuir equation, Freundlich equation and Dubinin-Astakov (D-A) equation, were compared in terms of their agreement with experimental data and their format impact on calculating coefficient of performance (COP) and refrigeration output (Qr), if one of the formats was used for presenting experimental data. Moreover, a sensitivity analysis was
conducted to reveal the parameters’ sensitivity to calculation of COP and Qr. It was found in this study that the D-A equation is the best state equation for presenting the adsorptive properties of the tested activated carbon/methanol working pairs in terms of the best agreement of P−T−x correlation and least sensitivities to parameters’ errors. A1-D dynamic model was established and validated experimentally, in which a local non-equilibrium treatment and dynamic boundary condition were introduced to the mathematical model. Regarding thermal non-equilibrium treatment, the temperatures of the local solid phase (activated carbon and adsorbed methanol) and local fluid phase were treated separately. Due to this non-equilibrium treatment, i.e. a two temperature treatment, convective heat transfer within the transport pores of activated carbon can be considered in the mathematical model. Moreover, a mathematically defined function was introduced to present the transient pressure process at the beginning of an adsorption process. Using this function, the temperature jump phenomenon can be well predicted by the mathematical model. After the mathematical model had been established and validated, a parametric analysis was conducted using the mathematical model. The effects of the cylindrical activated carbon column’s diameter and evaporating temperature on cycle time, COP and specific cooling power (SCP) were examined. Furthermore, a case study of cycle time optimisation was conducted. Finally, based on the parametric analysis, a practical solution using integrated groups of individual ART was proposed for home or domestic application. A preliminary
economics analysis was also conducted to evaluate the potential of this application.Thesis (M.Eng.Sc.) -- University of Adelaide, School of Mechanical Engineering, 2011
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Wang, Ji. "Study on Accumulated Performance of a Solar Thermal Powered Adsorption Refrigeration System." Thesis, 2019. http://hdl.handle.net/2440/120966.
Повний текст джерелаАнотація:
The thesis presents the outcomes of a study on the accumulated performance of a solar thermal powered adsorption refrigeration system. The solar-powered solid adsorption refrigeration system has numerous advantages including no moving parts during operation, using solar energy as the only heat input to run the whole system and being environmentally benign. The methanol and activated carbon selected as a working pair are due to advantages of their ice-making capacity, high efficiency and low price. The system, in its simplest form, runs according to the intermittent daily solar cycle, only making cooling at night and not during the daytime. The previous research mainly focuses on the individual daily cycle under the assumption that the system restores back to its original point every day, regardless of a real climate condition. In reality, for such a refrigeration system, its real performance depends not only on the current day’s weather condition but also on the previous day’s situation. However, the accumulated performance of the system over a period has only been little studied, which brings out three research questions that remain to be answered: How should a new configuration be modified, in order to make the system accumulate cooling capacity without removing ice daily? How many situations should be involved in the new accumulated cycles with consideration of real daily and hourly climate conditions? How should the mathematical models be established, in order to simulate the accumulated performance of the system more realistic and accurately? Therefore, the aim of the research is to develop a better understanding of an accumulated performance of an activated carbon/methanol refrigeration system if running over a period, e.g. days or weeks, by developing two validated simulation models. The thesis complies with the graduation by publication format of the University of Adelaide, which consists of one published journal article and one submitted journal article which is currently under review. The two articles are able to demonstrate the outcomes of the study and also form the main part of the thesis. Additional introduction and a literature review are provided to establish the context and significance of this work. The main outcomes of the study include: The new configuration of such a system, which can accumulate the cooling capacity without removing ice daily, has been established. In the configuration, the receiver and evaporator must be separated by adding separation valves between them. Possible cycles of such a system have been identified with consideration of realistic daily climate conditions. The mathematical model using daily weather data, with consideration of possible leftover liquid in the receiver, has been developed. The model has been validated against the published experimental data with an acceptable agreement. A desktop case-study for 50 consecutive days has been used to demonstrate the difference in the simulation of accumulated performance by two models, i.e. the model using daily climate conditions and the model under ideal assumptions. It has been concluded that the developed model using daily climate conditions is more accurate than the model under the ideal assumptions. The second mathematical model using hourly weather data has been developed based on seven possible cycles. These cycles, which are involved in the initial heating process and condensing process during the daytime, have been identified. The mathematical model using hourly climate conditions has been validated against the published experimental data with a more accurate agreement, compared to that of the model using daily climate conditions. A desktop case-study for three climatic days has been conducted to demonstrate the difference in the simulation of performance when the model using daily climate conditions and hourly climate conditions respectively. The daily performance (i.e. daily-evaporated methanol liquid) simulated from the new model could be 31.3% more than that from the first mathematical model in a special climatic day.Thesis (MPhil) -- University of Adelaide, School of Mechanical Engineering, 2019
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Sambath, Srivaths. "Study of Adsorption of Methanol in an Activated Carbon and Carbon Nanotube Matrix for Use in a Solar Based Refrigeration Cycle." Thesis, 2011. http://hdl.handle.net/1969.1/ETD-TAMU-2011-05-9075.
Повний текст джерелаАнотація:
This thesis seeks to investigate the adsorption capabilities of activated carbon and carbon nanotubes. The adsorption of methanol on both of these substances was tested for their application in a solar based refrigeration cycle. Research on carbon nanotubes and their growth has been carried out for applications in the semiconductor industry. Enough focus has not been given to the use of nanotubes for refrigeration purposes.
Adsorption refrigerators have been designed with the energy source being solar energy. Various adsorbent/adsorbate pairs have been tested in literature. The present work focuses on carbon nanotubes because theoretically, nanotubes should be able to adsorb better than activated carbon due to their high surface to volume ratios and hence a higher number of adsorption sites available for methanol to adsorb.
The amount of adsorption of methanol on nanotubes depends on whether the end caps of the nanotubes are open or closed and also on the hydrophilic nature of the nanotubes. Nanotubes with ends closed are supposed to adsorb less than the nanotubes with their ends opened. The ends of carbon nanotubes can be blocked because of iron and other impurities. In this project, nanotubes are annealed under high vacuum to open the end caps. The hydrophobic nature of the nanotubes is corrected by treating them with concentrated nitric acid. The hydrophobic nature of the nanotubes is corrected by treating them with concentrated nitric acid. The acid treated nanotubes are used to obtain adsorption data at different temperatures.
The adsorption of methanol on activated carbon, pristine and treated carbon nanotubes is measured at different temperatures. Electron microscopy is used to validate that annealing the nanotubes at high temperature under vacuum opens the end caps of the nanotubes. Finally, a matrix of nanotubes and carbon powder is prepared with different concentrations. The mixture is tested for adsorption of methanol.
It is observed that the carbon nanotubes, pristine or treated, do not perform better than activated carbon. However, performance seems to increase when mixtures of activated carbon and carbon nanotubes are used as adsorbent. Also, it is found that mixtures containing annealed nanotubes perform better than mixtures with pristine nanotubes. Kinetics of the adsorption process is calculated for the different adsorbents used, which is used to explain the increase in the amount of methanol adsorbed for the activated carbon-carbon nanotube mixture.
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Nitinkumar, D. Banker. "Development Of An Activated Carbon+ HFC 134a Adsorption Refrigeration System." Thesis, 2006. http://hdl.handle.net/2005/443.
Повний текст джерелаАнотація:
The demands facing the refrigeration industry are minimal usage of conventional energy sources for compression and avoidance of ozone depleting substances. One of the approaches to combat these issues is the use of thermally driven solid sorption compression with non-ozone depleting refrigerant. In this context, the research work presented in this thesis is devoted to a comprehensive thermodynamic analysis and development of a laboratory model of an activated carbon+ HFC 134a adsorption refrigeration system. The cooling load catered to by the laboratory model is 2-5 W, mainly for thermal management of electronics.
A complete thermodynamic analysis is carried out for the desorption temperatures varying from 75 to 90 oC, evaporating temperatures from -20 to 15oC and adsorption/condensing temperatures from 25 to 40 oC. A program on MatLab platform is developed for theoretical modeling. A new concept of thermal compression uptake efficiency (u) which is analogous to volumetric efficiency of a positive displacement compressor is introduced to consider the effect of void volume. The thesis also covers an investigation of two-stage and hybrid (thermal+ mechanical) cycle compression systems. It is possible to identify the conditions under which a two-stage gives a better performance than a single-stage one. It also shows that hybrid cycle system gives the best performance and saves ~40% of power compared to operation under the same conditions run with a single-stage mechanical compression refrigeration system.
A heat transfer analysis of the thermal compressor is carried out to evaluate non-uniformities in bed temperature. As a part of it, the thermal conductivity of the bed under adsorbed state has been calculated.
A laboratory model of activated carbon+ HFC 134a adsorption refrigeration system is fabricated to meet a 2-5 Watts cooling load based on the results from theoretical calculations. Experimental results show a fair match in the trends for the COP with analysis. The main aim of the research was to examine how effective the adsorption refrigeration system is in reducing the temperature rise of the heater used to simulate the electronic component. The heater that would have stabilized at 81, 97, 103 and 112 oC without any cooling for heat inputs of 3, 4, 4.4 and 4.9 W, respectively, would attain a cyclic steady state around 24, 26, 28, 31 oC. The influence of cycle time on the performance of the systems is also investigated.
It is concluded that an activated carbon+ HFC 134a adsorption refrigeration system can be a good supplement to conventional compression refrigeration systems. In situations where heat recovery imminent this system could be a good choice. For waste heat recovery and suppression of infrared signatures of electronic components, it is ideally suited where COP becomes immaterial.
Частини книг з теми "Activated carbon; methanol; adsorption refrigeration"
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Verma, Ashok, Satish, and Prodyut R. Chakraborty. "Parametric Study of Ammonia-Activated Carbon Two-Bed Adsorption Refrigeration System." In Advances in Energy Research, Vol. 1, 481–94. Singapore: Springer Singapore, 2020. http://dx.doi.org/10.1007/978-981-15-2666-4_47.
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Elsayed, Ahmed M., Hassan J. Dakkama, Saad Mahmoud, Raya Al-Dadah, and Waseem Kaialy. "Sustainable Cooling Research Using Activated Carbon Adsorbents and Their Environmental Impact." In Applied Environmental Materials Science for Sustainability, 186–221. IGI Global, 2017. http://dx.doi.org/10.4018/978-1-5225-1971-3.ch009.
Повний текст джерелаАнотація:
Conventional vapour compression system is one of the most utilized cycles in refrigeration and air conditioning systems, due to its compact size, the relatively low running cost, the high coefficient of performance and the wide range of the operating temperatures. Nevertheless, the system suffers from the high initial cost and the high-energy consumption. Unlike the vapour compression cycle, adsorption heat pumps have the advantage of utilizing waste heat reducing the energy consumption and the carbon emissions. Activated carbon is a porous adsorbent material that can be efficiently used in low temperature adsorption refrigeration systems. This chapter reviews the recent developments in the compact adsorption cooling systems using activated carbon regarding the enhancement of the material properties, the design of the sustainable adsorption systems and their environmental and cost perspectives.
Тези доповідей конференцій з теми "Activated carbon; methanol; adsorption refrigeration"
1
Anyanwu, Emmanuel E., and Nnamdi V. Ogueke. "Transient Analysis and Performance Prediction of a Solid Adsorption Solar Refrigerator." In ASME 2005 International Solar Energy Conference. ASMEDC, 2005. http://dx.doi.org/10.1115/isec2005-76211.
Повний текст джерелаАнотація:
The transient analysis and performance prediction of a solid adsorption solar refrigerator, using activated carbon/methanol adsorbent/adsorbate pair are presented. The mathematical model is based on the thermodynamics of the adsorption process, heat transfer in the collector plate/tube arrangement, and heat and mass transfers within the adsorbent/adsorbate pair. Its numerical model developed from finite element transformation of the resulting equations computes the collector plate and tube temperatures to within 5°C. The condensate yield and coefficient of performance, COP were predicted to within 5% and 9%, respectively. The resulting evaporator water temperature was also predicted to within 4%. Thus the model is considered a useful design tool for the refrigerator to avoid costly experimentation.
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Chekirou, Wassila, Nahman Boukheit, and Tahar Kerbache. "Effect of coupled heat and mass transfers on the performance of adsorptive solar refrigerator using the pair activated carbon / methanol." In 2008 Second International Conference on Thermal Issues in Emerging Technologies (ThETA). IEEE, 2008. http://dx.doi.org/10.1109/theta.2008.5167173.
Повний текст джерела
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Astina, I. Made, M. Irfan Zidni, Hary R. Hasugian, and Prihadi S. Darmanto. "Experiment of adsorption refrigeration system with working pairs of difluoromethane and activated carbon modified by sulfuric and nitric acids." In INTERNATIONAL CONFERENCE ON THERMAL SCIENCE AND TECHNOLOGY (ICTST) 2017. Author(s), 2018. http://dx.doi.org/10.1063/1.5046599.
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El Kalkha, H., and A. Mimet. "Implementation of Moroccan map solar cooling based on the dynamic study by a solar adsorption refrigeration machine working with activated carbon- ammonia pair using a sensor plane." In 2013 International Renewable and Sustainable Energy Conference (IRSEC). IEEE, 2013. http://dx.doi.org/10.1109/irsec.2013.6529694.
Повний текст джерела
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Sharafianardakani, Amirhossein, and Majid Bahrami. "A Quasi Steady State Model for Adsorption Cooling Systems: Automotive Applications." In ASME 2012 6th International Conference on Energy Sustainability collocated with the ASME 2012 10th International Conference on Fuel Cell Science, Engineering and Technology. American Society of Mechanical Engineers, 2012. http://dx.doi.org/10.1115/es2012-91362.
Повний текст джерелаАнотація:
In this study, an analytical quasi-steady state thermodynamic cycle of an adsorption cooling system (ACS) for automotive applications is presented which allows evaluating impact of different parameters on the ACS performance as well as effects of various working pairs: zeolite 13X/water, zeolite 4A/water and activated carbon-35/methanol. A comprehensive parametric study has been performed to investigate effects of temperature variation of the evaporator and condenser as well as the ICE exhaust gas temperature on the COP, cooling load produced by the evaporator and entropy generation of ACS with (or without) the heat recovery cycle (HRC). The results show that using the heat recovery cycle in the ACS can increase the COP of system up to 41% for zeolite 13X/water pair at the base-line condition. In addition, the parametric study shows that increasing regeneration and evaporation temperature increase the COP and entropy generation of ACS while increasing condensation temperature has negative effect on the COP and entropy generation. Finally, based on our modeling results, the ACS with the heat recovery cycle (HRC) and zeolite 13X/water pair are proposed for the automotive A/C applications.