Academic literature on the topic 'Ventilation – Efficiency – Simulation methods'
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Journal articles on the topic "Ventilation – Efficiency – Simulation methods"
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Vakulenko, D., and V. Mileikovskyi. "Simulation the effectiveness of heat recovery of the regenerative ventilator using different approaches." Ventilation, Illumination and Heat Gas Supply 41 (April 12, 2022): 32–38. http://dx.doi.org/10.32347/2409-2606.2022.41.32-38.
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Today buildings should be designed for energy efficiency class not less than C. This requires ventilation with heat recovery. On the market, there are different compact heat recovery ventilation units for decentralized ventilation. Regenerative ventilators represent a promising area of effective ventilation with exhaust air heat recovery. They operate cyclically for the inlet and outlet of air. These kinds of ventilators should work in a blocked pair(s) – one for input and one for output in each pair. If not, the effectiveness will decrease. A mathematical model of the ceramic heat regenerator in the regenerative ventilator “Twin Fresh” by Vents has been created to improve the efficiency of its operation. In previous works, on the basis of two different approaches, the operation of the heat regenerator was simulated. The first one uses M. Mikheev’s formula for the Nusselt number. The second one is computational fluid dynamic simulation by SolidWorks Flow Simulation. The efficiency coefficients obtained as a result of the simulation had a significant difference – up to 66.5 %. The aim of the work is to find alternative methods for adequately determining the efficiency of the ventilator. A mathematical simulation was performed using a different formula from “Novyi spravochnik khimika i tekhnologa. Protsessy i aparaty khimicheskikh tekhnologii”. This formula takes into account the Grashof number. Values obtained are significantly different from both previous ones – up to two times. There is no information in the literature about the experimental conditions for determining the Nusselt number, which was used in the simulation. Therefore, we can’t assume, what approach is closer to the conditions of the ceramic regenerator. There is a need to conduct experimental studies to determine the efficiency of the regenerative heat exchanger.
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Ayaz, Murat, Volkan Aygül, Ferhat Düzenli˙, and Erkutay Tasdemi˙rci˙. "Comparative Study on Control Methods for Air Conditioning of Industrial Paint Booths." Advanced Science, Engineering and Medicine 11, no. 11 (November 1, 2019): 1053–59. http://dx.doi.org/10.1166/asem.2019.2454.
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It is of great importance that each product in industrial production facilities is to be produced in the same quality and standard. Especially in the automotive industry, the painting process needs to be done under certain environmental conditions according to the paint properties used. Therefore, the temperature, humidity and air quality values of the paint booth are very important for a quality painting operation. In this study, adaptive control has been proposed to control of one-zone heating-ventilation system for the paint booths. The system has been modelled by using the Matlab/Simulink. Performance of the proposed control method has been compared with conventional control methods such as On/Off, PID, fuzzy logic in terms of accuracy, efficiency and response time. Simulation results show that the proposed adaptive control is effective in the Heating, Ventilating, and Air Conditioning (HVAC) systems temperature control applications. In addition, energy efficiency in HVAC systems has been provided with the proposed control model. Furthermore, thermal analysis of the system has been done to corroborate simulation results.
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Chen, Tingsen, Zhuangbo Feng, and Shi-Jie Cao. "The effect of vent inlet aspect ratio and its location on ventilation efficiency." Indoor and Built Environment 29, no. 2 (July 31, 2019): 180–95. http://dx.doi.org/10.1177/1420326x19865930.
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The total energy consumption of buildings in China has been increasing year by year, ventilation energy consumption accounts for more than 20% of the total building energy consumption. The optimisation of ventilation system design aiming at energy conservation is of great significance while keeping healthy indoor air quality. However, the current codes and standards are still lacking specification requirements for vents design, e.g. inlet size ratio or position, which can greatly impact on indoor airflow and ventilation efficiency. In this work, we investigated the aspect ratios of vent inlets and their locations on indoor air quality. Both experimental and numerical simulation methods were adopted. Ventilation efficiency is represented with the local average peak concentration 〈C ̅*〉A,max. Results showed that when vent inlet is in symmetric conditions (i.e. located in the middle of the sidewall) and the aspect ratio between the length and width of the vent inlet equals to 4, ventilation removal efficiency showed the best performance. These findings are of great importance to the engineering applicability and able to provide reference for future design standards.
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Xu, Jiang Rong, Wen Min Tian, Fang Chen, and Yan Liu. "Inhalable Particles Transportation of the Kitchen in Different Ventilation Methods." Applied Mechanics and Materials 71-78 (July 2011): 2158–62. http://dx.doi.org/10.4028/www.scientific.net/amm.71-78.2158.
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In order to evaluate the particle exposure level of people indoor, and to improve indoor air quality, research for the particle distribution in residential kitchen is important. In this paper, a residential kitchen is investigated numerically, and the spread and distribution of particles are simulated detailed using the mixture two-phase model. We focused on the particles transportation in different ventilation methods. The four different conditions are designed for simulating the two-phase flow pattern, and the results of particle concentration of different ventilation methods and different particles diameters are obtained. The simulating results are beneficial for increasing the particle removal efficiency and the design of reasonable ventilation methods.
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Kotsur, I. M., A. V. Hurazda, B. A. Dolia, and L. E. Shestov. "An energy efficient electric drive of air units." Electrical Engineering and Power Engineering, no. 1 (March 31, 2021): 18–25. http://dx.doi.org/10.15588/1607-6761-2021-1-2.
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Purpose. Improving the efficiency and energy performance of an asynchronous electric drive for stationary fan’s units of the main ventilation line of mines.
Methodology. The research was carried out using the methods of the theory of electrical circuits, mathematical physics, simulation, interpolation and approximation
Findings. The research of electromagnetic and energy processes in the asynchronous electric drive system with pulse control at a fan load, taking into account the variable aerodynamic parameters of the main ventilation line of mines. An electric drive system is able to respond with high accuracy and reliability to changes in the aerodynamic parameters of the main ventilation line of mines has been proven. This will also increase the power factor of the electric drive at a fan load up 0.8 to 0.93 p.u., and the efficiency up 92.5% to 94.5%, when regulating in the range of the operating slip of the rotor of the drive fan motor = 0.5 ÷, which, respectively, is on average up 0,25% to 40 higher in comparison with systems of an unregulated electric drive. Recommendations has been developed for the design and rational selection of the rated fan capacity for the main ventilation line to advance the best energy efficiency level of the electric drive.
Originality. The research of electro-mechanical, electro-energy power and aerodynamic processes in the dynamic modes of the fan electric drive was carried out. The fan-loaded "induction motor-converter" system has been proven to be self-regulating. It is able to respond with high accuracy and reliability even at low switching frequencies of the power chopper to any changes of the aerodynamic parameters of the main ventilation line of mines.
Practical value. Recommendations has been developed for the design and rational selection of the rated fan capacity for the main ventilation line to advance the best energy efficiency level of the electric drive.
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Darowski, M., G. Ferrari, D. M. Pisanelli, G. Tosti, and C. De Lazzari. "The Impact of Rotary Blood Pump in Conjunction with Mechanical Ventilation on Ventricular Energetic Parameters." Methods of Information in Medicine 45, no. 05 (2006): 574–83. http://dx.doi.org/10.1055/s-0038-1634120.
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Summary Objectives: Aim of this work is to study the impact of left ventricular rotary blood pump assistance, on energetic variables, when mechanical ventilation (MV) of the lungs is applied. Methods: Computer simulation was used to perform this study. Lumped parameter models reproduce the circulatory system. Variable elastance models reproduce the Starling’s law of the heart for each ventricle. After the reproduction of ischemic heart disease left ventricular assistance was applied using a model of rotary blood pump. The pump speed was changed in steps and was assumed to be constant during each step. The influence of mechanical ventilation was introduced by different values of positive mean thoracic pressure. Results: The increase of the rotational speed has a significant influence on some ventricular energetic variables. In fact it decreased left ventricular external work, left and right ventricular pressure-volume area and the left ventricular efficiency. Finally, it increased the right ventricular efficiency but had no influence on the right ventricular external work. The increase of thoracic pressure from –2 to +5 mmHg caused a significant decrease of external work, pressure-volume area (right ventricular pressure-volume area dropped up to 50%) and an increase of right ventricular efficiency (by 40%) while left ventricular efficiency remained almost stable. Conclusions: Numerical simulation is a very suitable tool to predict changes of not easily measurable parameters such as energetic ventricular variables when mechanical assistance of heart and/or lungs is applied independently or simultaneously.
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Shaptala, V., E. Hukalenko, N. Severin, and Y. Gusev. "DEVICES AND VENTILATION PROCESS DURING EXECUTION ELECTRIC WELDING." Bulletin of Belgorod State Technological University named after. V. G. Shukhov 5, no. 9 (October 3, 2020): 21–29. http://dx.doi.org/10.34031/2071-7318-2020-5-9-21-29.
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The main direction of normalizing the parameters of the air during electric welding is proposed to consider the installation of an integrated ventilation system that combines local exhaust ventilation of welder jobs and general ventilation of rooms. In the article using the computer simulation method, the fields of air mobility, its temperature and concentration of harmful impurities are calculated and a comparative analysis of the main types of stationary devices for local exhaust ventilation of electric welding jobs: exhaust umbrellas, welding panels, and suction blowers, as well as the conditions for effective use of rotary suction pumps. Factors affecting the efficiency of their work are identified and combinations of influencing factors that provide the maximum permissible concentration of harmful emissions in the welders' working areas are established. The conditions are determined under which the general exchange effect of local suction is sufficient to maintain indoor concentration at the MPC level. The results obtained can be used to develop engineering methods for calculating and optimizing ventilation devices and systems, as well as to analyze structural and design solutions for ventilation devices in electric welding plants.
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Liu, Zongxin, Changfa Ji, Pengju Zhang, and Huan Zhang. "Optimization research on indoor ventilation mode of cave dwellings in northern Shaanxi." E3S Web of Conferences 356 (2022): 03047. http://dx.doi.org/10.1051/e3sconf/202235603047.
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Cave dwelling is a characteristic residential building in northern Shaanxi. It is not only a masterpiece created by local residents in accordance with nature and local cases, but also meets the requirements of green ecology and sustainable development. In order to understand the influence of ventilation on the indoor environment of cave dwellings in northern Shaanxi, a representative traditional cave dwelling was selected as the research object. Based on the meteorological data in Yan'an and the actual measurement of indoor and outdoor thermal parameters, the methods of theoretical analysis, field testing and numerical simulation were adopted to study the indoor airflow distribution of cave dwellings under different ventilation methods, the results show that: the cave dwellings in northern Shaanxi have good thermal insulation performance, and the indoor temperature fluctuation is small; the relative humidity in the cave dwelling is relatively high, which is opposite to the trend of temperature change; reducing the humidity is the ventilation of the cave dwelling. The main task; the indoor wind speed is too small to form effective ventilation. Adjusting the size of the skylight can improve the natural ventilation in summer to optimize indoor ventilation. Through optimization analysis, when the size of the skylight is 0.5m*0.5m, the indoor airflow velocity changes between 0 and 0.3m/s, the ventilation efficiency is high, and the ventilation effect is high. Good, there will be no eddy current in the room, which can effectively remove moisture and enhance lighting, which can provide a basis for the opening of ventilation skylights in new local caves. Effectively improve indoor heat and humidity environment.
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Kobylkin, S. S., A. N. Timchenko, and A. S. Kobylkin. "Use of Computer Simulation in the Selection of Operating Parameters for the Dust Extractor Built into the Roadheaders." Occupational Safety in Industry, no. 3 (March 2021): 21–27. http://dx.doi.org/10.24000/0409-2961-2021-3-21-27.
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An increase in the rate of mine workings excavation leads to the ingress of large amount of dust into the mine atmosphere. Ensuring the aerological safety of coal mines drifting faces according to the dust factor is an urgent task. To reduce the level of dustiness of a dead mine roadheading during its sinking, the scrubbers built into the roadheader are used. In this case, the joint operation of the ventilation system and the dust extraction system is not considered. This leads to the risk of occurrence of the stagnation zones or air recirculation near the bottom-hole area. At the intensive ventilation with a high air flow, the dust is removed, and the dust extraction system becomes useless. As the analysis showed, currently there are no methods that allow to take into account these two processes simultaneously. The idea of using computer modeling in the Ansys software package is proposed. To correctly solve the problems of optimizing the scrubber operation, a method is given for determining the grid parameters, as well as for setting the initial and boundary conditions. All the data obtained were verified at the coal mines of Russia. To achieve maximum efficiency, it is proposed to use the dust and aerodynamic criteria of the scrubber operation, which will allow to increase the mining operations safety. The dust criterion characterizes the efficiency of the dust extraction systems. The aerodynamic criterion allows to determine the joint operation mode in which there will be no recirculation and not ventilated zones. To take into account the large number of factors that affect the ventilation of a dead mine working and the operation of the dust extraction system, an artificial intelligence was added to computer modeling in system design. It is implemented in the ANSYS DesignXplorer module. In a given range of changing factors during the operation of artificial intelligence, by performing multiple calculations, such a combination of operating parameters of the two systems is obtained, at which the efficiency is maximum.
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Sverdlov, A. V., M. A. Volkov, S. V. Rykov, and I. V. Kudryavtseva. "Similarity Theory when Selecting the Test Fire Parameters During Commissioning Tests of the System of Smoke Ventilation at a Closed Car Park." IOP Conference Series: Earth and Environmental Science 988, no. 3 (February 1, 2022): 032081. http://dx.doi.org/10.1088/1755-1315/988/3/032081.
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Abstract Fire protection of closed car parks, where it is possible to have a massive stay of people, is the most important and most crucial task when designing such facilities. The efficiency and effectiveness of smoke ventilation systems is achieved through compliance with design rules and numerical simulation of air distribution. The most reliable method is an experimental check of the efficiency of smoke ventilation. It is not possible to reproduce a real fire in the conditions of an object without damaging the structures of a building or a facility; therefore, tests are carried out with reduced, safe fire parameters. Based on the similarity theory, the article discusses the methodology for scaling test fire parameters and smoke ventilation parameters, which allows obtaining results relevant to the design fire parameters. In this case, the positive test results with lower parameters of the test fire confirm the design limits of the smoke distribution and the possibility of evacuating people from the car park in case of a fire having design parameters. An alternative to these scaling methods can only be the prediction of design test parameters and conditions based on the same calculation method, as well as the case when the prediction of the test results is confirmed by observations.
Dissertations / Theses on the topic "Ventilation – Efficiency – Simulation methods"
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Rohdin, Patrik. "Energy efficiency and ventilation in Swedish industries barriers, simulation and control strategy." Doctoral thesis, Linköpings universitet, Energisystem, 2008. http://urn.kb.se/resolve?urn=urn:nbn:se:liu:diva-15531.
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The energy issue is presently in focus worldwide. This is not only due to increasing environmental concern regarding energy related emissions, but also due to the trend of increasing energy prices. Energy usage in the industrial sector in Sweden today represents about one third of the national energy use. A substantial part of that is related to support processes such as heating, ventilation and cooling systems. These systems are important as they are related both to energy cost and indoor climate management as well as to the health of the occupants. The purpose of this thesis is to reach a more comprehensive view on industrial energy efficiency and indoor environment issues related to industrial ventilation. This has been studied in three themes where the first part addresses barriers to energy efficiency in Swedish industries, the second theme discuss simulation as decision support, and the third studies the variable air volume system in industrial facilities. In the first theme three different studies were made: the first studies non-energy intensive companies in Oskarshamn in Sweden, the second studies the energy intensive foundry industry and the third study was part of an evaluation of a large energy efficiency program called Project Highland. These studies had several findings in common, such as the importance of a strategic view on the energy issue and the presence of a person with real ambition with power over investment decisions related to energy issues at the company. The studies also show that several information related barriers are important for decision makers at the studied companies. This shows that information related barriers are one reason in why energy efficient equipment is not implemented. In the second theme the use of simulation in the form of Computational Fluid Dynamics (CFD) and Building Energy Simulation (BES) are used as decision support for industrial ventilation related studies at two different industries, one foundry is investigated and one dairy. BES has mainly been used to simulate energy and power related parameters while CFD was used to give a detailed description of the indoor and product environment. Together these methods can be used to better evaluate the energy, indoor and product environment and thus enable the implementation of more efficient heating, ventilation and air-conditioning systems. In the third theme the use of Variable Air Volume (VAV) systems was evaluated, and was found to be an efficient way to reduce energy use at the studied sites. At the studied foundry the VAV system is predicted to reduce space heating and electricity use by fans by about 30%, and in the dairy case by about 60% for space heating and 20% for electricity.
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Dowrani, Ali Akbar Gharooni. "Efficiency of air cooler coil defrost methods and the effect of these methods on the refrigeration cycle performance." Thesis, University of Liverpool, 1991. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.316876.
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Boyle, Patrick. "Energy Performance Simulation of Different Ventilation Systems in Sweden and Corresponding Compliance in the LEED Residential Rating System." Thesis, Högskolan Dalarna, Energiteknik, 2020. http://urn.kb.se/resolve?urn=urn:nbn:se:du-34516.
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The importance of energy efficiency in the operation of the built environment is becoming increasingly important. Energy use in the building sector has exceeded both transportation and industry, while within buildings heating, ventilation, and air conditioning has the greatest share. In light of the recent pandemic forcing governments to issue quarantines and stay-at-home orders people are spending even more time indoors, this further emphasizes the importance of proper ventilation and the impacts on energy use. The purpose of this research was to perform a case study of a low environmental impact demonstration house to compare the energy performance of various ventilation strategies. The ventilation strategies varied by overall airflow rate, control strategy, and the presence of heat recovery. Performance was evaluated by establishing a model in IDA ICE, an equation-based modeling tool for the simulation of indoor thermal climate and energy use. The results showed energy savings due to demand-control with a reduction of 12.5%. Results also showed similar savings with a heat recovery system, indicating that any savings in heat loss due to heat recovery is at the expense of increased auxiliary energy. In this particular case, the benefit of upgrading to a heat recovery system from simple demand control set up is not readily apparent. Results also demonstrated trends and possible complications useful to future research plans that aim to measure real world ventilation performance, including how differences in the number and location of sensors impact the efficacy of the demand-controlled systems. A secondary aim was to observe how a newly constructed, low environmental impact home built in Sweden performs according the residential LEED energy budget. The results demonstrated that constructing a house using low impact materials with low embodied energy does not have to negatively impact energy performance, scoring extremely well in the Energy and Atmosphere category of a widely used sustainable building rating system.
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Rundblad, Mattias, and Nasim Walid. "Systemlösningar för ventilation på en förskola : Energi- samt ekonomiutvärdering för CAV- och VAV-ventilation för olika luftbehandlingsaggregat." Thesis, Mälardalens högskola, Akademin för ekonomi, samhälle och teknik, 2017. http://urn.kb.se/resolve?urn=urn:nbn:se:mdh:diva-36341.
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Energieffektiviseringar behövs för att klara klimatmålen. Syftet med detta arbete har därför varit att undersöka ventilationen i förskolebyggnaden Rymden i Eskilstuna kommun. Fokus i arbetet har legat på att göra en analys på energibesparingar där variabelt luftflöde, VAV-system och konstant luftflöde, CAV-system jämförs i tre olika scenarier. Metodiken för att lösa arbetets frågeställningar har varit genom informationsinsamling, beräkningsprogram, intervju samt platsbesök. Informationsinsamling har varit i form av vetenskapliga tidskrifter samt arbeten som behandlar det aktuella problemområdet. Olika programvaror har använts, dessa är MagiCAD, IDA ICE, Sektionsdata 4.21 samt Microsoft Excel. För ökad förståelse för den aktuella byggnaden har platsbesök gjorts på förskolebyggnaden samt en intervju med den projektöransvarige för ventilationen i förskolan. Resultatet visar att den mest energieffektiva systemlösningen är en roterande värmeväxlare med VAV-styrning i kombination med en korsströmsvärmeväxlare för köksavdelningen. VAV-styrning med en sådan systemlösning har en total årlig energianvändning på 20 684 kWh, medan CAV-systemet med samma systemlösning använder 30 900 kWh. Ekonomisk analys visar däremot att CAV-systemet med samma systemlösning är mest lönsam. Den totala livscykelkostnaden, LCC ligger på 2 386 857 kr för CAV-systemet vid en kalkyltid på 30 år, i jämförelse med 2 420 117 kr för VAV-systemet. För att VAV-systemet skall vara lönsam, visar känslighetsanalysen att kalkylräntan måste sjunka från 5 % till 2,56 % eller energiprisutvecklingen öka med 2,44 % årligen eller en sänkning av den årliga underhållskostnaden för VAV-styrning med 2 164 kr. Övrig känslighetsanalys visar att vid nederbörd då personer stannar inomhus är det fördel för VAV-systemet, då skillnaden i total LCC-kostnad sjunker med 1 758 kr. Vid 74 % av personnärvaro minskar LCC-skillnaden mellan systemen från 39 240 kr till 26 371 kr, alltså utgör detta även en fördel för VAV-systemet. Slutsatsen som dras för förskolebyggnaden Framtiden är att större energibesparingar kan göras med ett VAV-system, men ett CAV-system är bättre ur en ekonomisk synpunkt. Känslighetsanalysen visar dock att små förändringar behövs för att VAV-systemet skall bli ekonomiskt lönsamt. Andra faktorer som påverkar valet mellan VAV- och CAV-system är exempelvis en minskning av personnärvaron relativt till det dimensionerade. En sådan minskning utgör en fördel för VAV-systemet. Detta på grund av att med ett CAV-system överventileras byggnaden. Även högre specifik fläkteffekt har en stor betydelse i valet, då mer energiåtgång till fläktarna leder till större energibesparing för VAV-system. En högre temperaturverkningsgrad för luftbehandlingsaggregat medför däremot en fördel för CAV-system.This thesis work has been done in collaboration with Sweco Systems in Eskilstuna, Sweden. The purpose with this work is to investigate the ventilation in a preschool in Eskilstuna. The focus of the work is to analyze the potential energy savings of using a variable air volume system instead of a constant air volume system. An analysis is also made to investigate the economical profitability of three different scenarios. The method used to solve the problem formulation has been through gathering information, in form of scientific journals in the current problem area. Information has also been gathered through an interview and a site visit. Various software has been used in this thesis work for calculations, such as MagiCAD, IDA ICE, Sektionsdata 4.21 and Microsoft Excel. The result shows that the most energy efficient solution is a rotary heat exchanger with variable air volume control in combination with a cross-flow heat exchanger for the kitchen section. However, the most profitable solution from an economical point of view is the same system, but with constant air volume control. Sensitivity analysis shows that for a profitable variable air volume system, either the interest rate has to be lowered from 5 % to 2,56 %, the energy price needs to increase by 2,44 % yearly. Or maintenance cost for the variable air volume system needs to be lowered by 2 164 kr. The conclusion of this thesis work is that energy savings can be done with a variable air volume system. However from an economical point of view, the constant air volume is better than variable air volume for the investigated preschool. The sensitivity analysis shows that small changes are needed to make a variable air volume system profitable. The choice between the systems are influenced by certain factors. A decrease of the attendance than the dimensioned are an advantage for variable air volume systems. This is due to the fact that a constant air volume system ventilates more than needed. A higher specific fan power number are also of great importance in the choice, as more energy consumption by the fans leads to greater energy savings for variable air volume systems.
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Widström, Torun. "Enhanced Energy Efficiency and Preservation of Historic Buildings : Methods and Tools for Modeling." Licentiate thesis, KTH, Byggnadsteknik, 2012. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-102544.
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As the environmental impacts of the energy usage of the world today becomes more and more evident, enhancement of energy performance of the already existing building stock becomes more urgent. Buildings belonging to the cultural heritage are often the ones that are most difficult to deal with in this context. The subject of this thesis is the use of building simulation of historic buildings. The task here is to identify and when necessary develop simulation tools and methods that are suitable for planning of retrofitting strategies in historic buildings, and to identify and analyze what demands such tools and methods would have to fulfill, in what contexts different simulation strategies are suitable, how the demands on the tools might be met and what results and how the results would facilitate the decision making process in the most optimal way. A powerful means to acquire such analyses is the use of whole-building simulation. In the case of historical buildings there are several aspects to take into consideration, determining the choice of simulation tool and method. This thesis includes Investigation of the variability of the demands on simulation tools and methods that the historic buildings pose, and its implication on complexity of the simulation process, and suggestion of a complexity index tool. Investigation of the whole-building simulation process and how it complies with the demands identified, and how the exergy concept can be used, exemplified by a case study. Identification of a need for a tool and method for a large amount of cases not easily covered by abundantly available tools and methods Suggestion of a tool and method to address these cases, and presentation of a case study where the suggested tool and method have been applied, with good agreement between the simulated and measured values. One important feature of the suggested tool is the Very Small Wall-part Method, that includes the assessment of especially damage prone points into the whole-building simulation model, otherwise unable to accommodate these points. Another is the damage risk assessment feature where a mould risk prediction tool is presented.QC20120920
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Vadambacheri, Manian Karthik. "Novel Methods to Improve the Energy Efficiency of Multi-core Synchronization Primitives." University of Cincinnati / OhioLINK, 2017. http://rave.ohiolink.edu/etdc/view?acc_num=ucin1511858440610247.
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Brugnera, Rosilene Regolão. "Potencial de economia de energia em edifícios de escritórios com estratégias de ventilação híbrida." Universidade de São Paulo, 2014. http://www.teses.usp.br/teses/disponiveis/102/102131/tde-30102014-152311/.
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Grandes fachadas envidraçadas têm se tornado comuns em edifícios de escritórios, desconsiderando elementos importantes como as janelas na redução do seu consumo energético, por meio da obtenção da iluminação e ventilação naturais. Dessa forma, o objetivo principal desta pesquisa é avaliar o potencial de economia de energia em edifícios de escritórios por meio da utilização de estratégias de ventilação híbrida, em duas regiões climáticas brasileiras distintas. O método consiste em medições com sensores para aferir dados de temperatura e umidade no momento em que são acionados os condicionadores de ar, a fim de obter a temperatura de setpoint. Tal resultado foi utilizado em simulações computacionais do desempenho térmico e da iluminação natural através dos programas EnergyPlus e Daysim respectivamente. Foi analisado um modelo de edifício de escritórios, com um sistema de iluminação eficiente (dimerizável) em que foram inseridas estratégias de ventilação híbrida, a fim de se obter a influência na economia de energia devido à redução do uso do condicionamento artificial de ar (nos períodos em que isso foi possível). Os resultados apresentaram uma redução no consumo do ar condicionado em torno dos 30%, enquanto que o impacto da ventilação híbrida no consumo de energia total do edifício apresentou-se na faixa dos 12%. Todavia, com a utilização de tais estratégias alcançou-se uma redução de até 84% do desconforto térmico nos ambientes. Como conclusão do trabalho tem-se que, utilizando-se um sistema de iluminação natural eficiente, o impacto da ventilação híbrida no potencial de economia de energia, dependendo do caso, pode não ser tão expressivo, ao passo que a redução no nível de desconforto térmico é bastante significativa.Large glazed facades have become common in office buildings and important elements, like windows to obtain natural lighting and ventilation to reduce their energy consumption have been ignored. This dissertation evaluates the potential of energy savings in office buildings through the use of hybrid ventilation strategies in two different Brazilian climatic regions. The method consists in measuring sensors for collecting humidity and temperature data at the time air conditioners are started so as to obtain the setpoint temperature. The results were used in computer simulations of both thermal performance and daylighting through EnergyPlus and Daysim software, respectively. A model of the office building, with efficient lighting (dimmable), was analyzed. Hybrid ventilation strategies were adopted for verifying the influence on energy savings due to a reduced use of artificial air conditioning (in periods in which it was possible). The results show a 30% reduction in the consumption of air conditioning and a 12% impact of hybrid ventilation on the total energy consumption of the building. However, such strategies caused an 84% reduction in the thermal discomfort in the environment. According to the results, the impact of hybrid ventilation on the potential energy savings by the use of efficient daylighting, in some cases, may not be so significant, whereas the reduction in the level of thermal discomfort is quite significant.
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Ertem-Müller, Senem [Verfasser]. "Numerical Efficiency of Implicit and Explicit Methods with Multigrid for Large Eddy Simulation in Complex Geometries / Senem Ertem-Müller." Aachen : Shaker, 2003. http://d-nb.info/1181602696/34.
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Mason, Kevin Richard. "Development of numerical schemes to improve the efficiency of CFD simulation of high speed viscous aerodynamic flows." Thesis, Swansea University, 2013. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.678434.
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Starke, Martin, Benjamin Beck, Denis Ritz, Frank Will, and Jürgen Weber. "Frequency based efficiency evaluation - from pattern recognition via backwards simulation to purposeful drive design." Technische Universität Dresden, 2020. https://tud.qucosa.de/id/qucosa%3A71072.
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The efficiency of hydraulic drive systems in mobile machines is influenced by several factors, like the operators’ guidance, weather conditions, material respectively loading properties and primarily the working cycle. This leads to varying operation points, which have to be performed by the drive system. Regarding efficiency analysis, the usage of standardized working cycles gained through measurements or synthetically generated is state of the art. Thereby, only a small extract of the real usage profile is taken into account. This contribution deals with process pattern recognition (PPR) and frequency based efficiency evaluation to gain more precise information and conclusion for the drive design of mobile machines. By the example of an 18 t mobile excavator, the recognition system using Hidden – Markov - Models (HMM) and the efficiency evaluation process by means of backwards simulation of measured operation points will be described.
Books on the topic "Ventilation – Efficiency – Simulation methods"
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Zurada, Jacek M., and Boris Igelnik. Efficiency and scalability methods for computational intellect. Hershey, PA: Information Science Reference, 2013.
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Persily, Andrew K. A modeling study of ventilation in manufactured houses. Gaithersburg, MD: U.S. Dept. of Commerce, Technology Administration, National Institute of Standards and Technology, 2000.
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Swaffield, J. A. Simulation and modelling of flow in drains and air vents. London: Spon Press, 2010.
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Brandt, Achi. Recent advances in achieving textbook multigrid efficiency for computational fluid dynamics simulations. Hampton, VA: Institute for Computer Applications in Science and Engineering, NASA Langley Research Center, 2002.
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Swaffield, J. A. Transient airflow in building drainage systems. Abingdon, Oxon: Spon Press, 2010.
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Swaffield, J. A. Transient airflow in building drainage systems. London: Spon Press, 2010.
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Transient airflow in building drainage systems. Abingdon, Oxon: Spon Press, 2010.
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Palmiter, Larry S. SUNDAY calibration: Informal progress report. Seattle, WA: Ecotope, 1998.
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Brandt, Achi. Barriers in achieving textbook multigrid efficiency (TME) in CFD. Hampton, Va: Institute for Computer Applications in Science and Engineering, NASA Langley Research Center, 1998.
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Brandshaug, Terje. Stability of disposal rooms during waste retrieval. Washington, DC: Division of High-Level Waste Management, Office of Nuclear Material Safety and Safeguards, U.S. Nuclear Regulatory Commission, 1989.
Find full textBook chapters on the topic "Ventilation – Efficiency – Simulation methods"
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Stauffer, Dietrich, Friedrich W. Hehl, Nobuyasu Ito, Volker Winkelmann, and John G. Zabolitzky. "Methods of Higher Accuracy (and Efficiency)." In Computer Simulation and Computer Algebra, 19–35. Berlin, Heidelberg: Springer Berlin Heidelberg, 1993. http://dx.doi.org/10.1007/978-3-642-78117-9_3.
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Sharad, Shekhar A., and Sandeep Kumar Shukla. "Optimizing System Models for Simulation Efficiency." In Formal Methods and Models for System Design, 317–30. Boston, MA: Springer US, 2004. http://dx.doi.org/10.1007/978-1-4020-8052-4_12.
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Rostek, Katarzyna, and Radosław Zając. "Simulation Modeling to Verify the Efficiency of Information Transfer." In Experimental and Quantitative Methods in Contemporary Economics, 217–28. Cham: Springer International Publishing, 2019. http://dx.doi.org/10.1007/978-3-030-30251-1_16.
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Sang, Xian-chen, Wei Shao, Min Chen, Long-fei Yang, and Quan Jin. "Qualitative Criterion and Simulation Analysis of Ventilation Efficiency of New High Protection Louver." In Proceedings of the Eighth Asia International Symposium on Mechatronics, 312–18. Singapore: Springer Nature Singapore, 2022. http://dx.doi.org/10.1007/978-981-19-1309-9_33.
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Samawi, Hani Michel. "Improving the Efficiency of the Monte-Carlo Methods Using Ranked Simulated Approach." In Monte-Carlo Simulation-Based Statistical Modeling, 17–40. Singapore: Springer Singapore, 2017. http://dx.doi.org/10.1007/978-981-10-3307-0_2.
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Peluchetti, Stefano, and Gareth O. Roberts. "A Study of the Efficiency of Exact Methods for Diffusion Simulation." In Monte Carlo and Quasi-Monte Carlo Methods 2010, 161–87. Berlin, Heidelberg: Springer Berlin Heidelberg, 2012. http://dx.doi.org/10.1007/978-3-642-27440-4_7.
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Chen, Ding-Geng. "Statistical Meta-Analysis and Its Efficiency: A Real Data Analysis and a Monte-Carlo Simulation Study." In Modern Biostatistical Methods for Evidence-Based Global Health Research, 137–65. Cham: Springer International Publishing, 2022. http://dx.doi.org/10.1007/978-3-031-11012-2_6.
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Rozanek, M., K. Roubik, and Z. Horakova. "Simulation of the Different Respiratory Mechanics Effect upon the Efficiency of Artificial Lung Ventilation Using Mathematical Model of the Respiratory System." In IFMBE Proceedings, 1674–76. Berlin, Heidelberg: Springer Berlin Heidelberg, 2009. http://dx.doi.org/10.1007/978-3-642-03882-2_444.
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Bacharoudis, Konstantinos, Atanas Popov, and Svetan Ratchev. "Application of Advanced Simulation Methods for the Tolerance Analysis of Mechanical Assemblies." In IFIP Advances in Information and Communication Technology, 153–67. Cham: Springer International Publishing, 2021. http://dx.doi.org/10.1007/978-3-030-72632-4_11.
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AbstractIn the frame of a statistical tolerance analysis of complex assemblies, for example an aircraft wing, the capability to predict accurately and fast specified, very small quantiles of the distribution of the assembly key characteristic becomes crucial. The problem is significantly magnified, when the tolerance synthesis problem is considered in which several tolerance analyses are performed and thus, a reliability analysis problem is nested inside an optimisation one in a fully probabilistic approach. The need to reduce the computational time and accurately estimate the specified probabilities is critical. Therefore, herein, a systematic study on several state of the art simulation methods is performed whilst they are critically evaluated with respect to their efficiency to deal with tolerance analysis problems. It is demonstrated that tolerance analysis problems are characterised by high dimensionality, high non-linearity of the state functions, disconnected failure domains, implicit state functions and small probability estimations. Therefore, the successful implementation of reliability methods becomes a formidable task. Herein, advanced simulation methods are combined with in-house developed assembly models based on the Homogeneous Transformation Matrix method as well as off-the-self Computer Aided Tolerance tools. The main outcome of the work is that by using an appropriate reliability method, computational time can be reduced whilst the probability of defected products can be accurately predicted. Furthermore, the connection of advanced mathematical toolboxes with off-the-self 3D tolerance tools into a process integration framework introduces benefits to successfully deal with the tolerance allocation problem in the future using dedicated and powerful computational tools.
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Kuzmina, Kseniia, and Ilia K. Marchevsky. "On the Efficiency of the Parallel Algorithms in VM2D Open Source Code for 2D Flows Simulation Using Vortex Methods." In IUTAM Symposium on Recent Advances in Moving Boundary Problems in Mechanics, 147–59. Cham: Springer International Publishing, 2019. http://dx.doi.org/10.1007/978-3-030-13720-5_13.
Full textConference papers on the topic "Ventilation – Efficiency – Simulation methods"
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Case, John B., and David C. Buesch. "Simulation of Ventilation Efficiency, and Pre-Closure Temperatures in Emplacement Drifts at Yucca Mountain, Nevada, Using Monte Carlo and Composite Thermal-Pulse Methods." In ASME 2004 Heat Transfer/Fluids Engineering Summer Conference. ASMEDC, 2004. http://dx.doi.org/10.1115/ht-fed2004-56617.
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Predictions of waste canister and repository driftwall temperatures as functions of space and time are important to evaluate pre-closure performance of the proposed repository for spent nuclear fuel and high-level radioactive waste at Yucca Mountain, Nevada. Variations in the lithostratigraphic features in densely welded and crystallized rocks of the 12.8-million-year-old Topopah Spring Tuff, especially the porosity resulting from lithophysal cavities, affect thermal properties. A simulated emplacement drift is based on projecting lithophysal cavity porosity values 50 to 800 m from the Enhanced Characterization of the Repository Block cross drift. Lithophysal cavity porosity varies from 0.00 to 0.05 cm3/cm3 in the middle nonlithophysal zone and from 0.03 to 0.28 cm3/cm3 in the lower lithophysal zone. A ventilation model and computer program titled “Monte Carlo Simulation of Ventilation” (MCSIMVENT), which is based on a composite thermal-pulse calculation, simulates statistical variability and uncertainty of rock-mass thermal properties and ventilation performance along a simulated emplacement drift for a preclosure period of 50 years. Although ventilation efficiency is relatively insensitive to thermal properties, variations in lithophysal porosity along the drift can result in a range of peak driftwall temperatures can range from 40 to 85 °C for the preclosure period.
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Liu, Pin, Yingzi Jin, Yanping Wang, Hongyu Qian, and Li Zhang. "Study on the Aerodynamic Performance of Small Axial Flow Counter-Rotating Fans." In ASME-JSME-KSME 2011 Joint Fluids Engineering Conference. ASMEDC, 2011. http://dx.doi.org/10.1115/ajk2011-06091.
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Small axial flow fans are used as cooling components for computers, electronic equipments and other electronic components. With the increasing power of electrical equipment, the demand for lower noise and higher ventilation of cooling fans to improve heat transfer effects is also increasing. Traditional methods of improving ventilation by raising the fan’s rotation speed causes a decrease in efficiency and an increase in noise. The researchers have found that higher pressure, ventilation and efficiency can be achieved in a small space by counter-rotating fans than single fans. In this paper, 3D simulation has been done on flow field of counter-rotating fans for heat exchange, and the method of large eddy simulation (LES) and FW-H acoustic model have been used to simulate the distribution of noise field. The frequency spectrum from different sound sources has been analyzed, and the optimal ranges of the distance and gap between rotors have been determined. All that will provide a theoretical basis for researches on their characteristics and structure design.
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Şen, Emine, and Touraj Ashrafian. "An Investigation on Natural Window Ventilation: Improving Indoor Air Quality and Energy Efficiency in an Office Building." In 4th International Conference of Contemporary Affairs in Architecture and Urbanism – Full book proceedings of ICCAUA2020, 20-21 May 2021. Alanya Hamdullah Emin Paşa University, 2021. http://dx.doi.org/10.38027/iccaua2021317n19.
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With the increment in time spent indoors, the contingence between building occupants and indoor air pollution has been lengthened. Accordingly, indoor air quality became a significant factor since the poor conditions can influence the occupants’ health and efficiency. Indoor air quality is mainly concerned with physical and thermophysical factors in conditioned environments and is related to occupants’ satisfaction levels on a variety of variables such as fresh air adequacy, air temperature, odor, humidity, and air velocity. This paper aims to investigate natural ventilation occupant-control methods to improve indoor air quality and increase building energy efficiency considering clean air intake levels and indoor air temperature levels. For this, variables related to climatic conditions, ventilation systems, and occupant’s control on window opening were investigated to provide healthy and liveable conditions. To comply with these goals, in an open-plan office building, the levels of indoor air quality were determined with the help of DesignBuilder simulation by comparing obtained values under different case modeling variations.
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Panindre, Prabodh, Sunil Kumar, Atulya Narendranath, Vinay Kanive Manjunath, and John Ceriello. "Technique to Improve Performance of Positive Pressure Ventilation Tactic in High-Rise Fires." In ASME 2011 International Mechanical Engineering Congress and Exposition. ASMEDC, 2011. http://dx.doi.org/10.1115/imece2011-62911.
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Positive Pressure Ventilation (PPV) is a firefighting tactic that can assist firefighters in venting of smoke and high temperature combustion products in a more efficient manner and make the fire-rescue /suppression operation safer than without PPV. The pressure created by PPV operation must be greater than that of created by spread of fire. In real-life structures such as high-rise buildings, considering the leakages and size of stairwells, it becomes difficult to achieve the desired pressure at upper floors using PPV operation. With the help from FDNY (Fire Department of New York), on-site tests and computer simulation techniques were performed to study the behavior of PPV tactic. A technique was developed that significantly increases the positive pressure level achieved by a typical PPV operation. The efficacy of this technique was tested by conducting on-site experiments and numerical simulation methods using computational fluid dynamics software - Fluent 12.0 and NIST’s Fire dynamic simulator (FDS 5.0). The results of on-site experiments and numerical simulation methods found to be in close agreement with each other and confirmed the efficacy of this technique in improving the performance of typical PPV operation. This paper describes the results obtained from these on-site tests and numerical simulation methods. As FDNY is in the phase of implementing this instrument to ease and improve the PPV deployment operation, numerical simulation methods have been used to optimize this technique and the analysis discussed in this study also simplifies the PPV fan deployment operation for firefighters.
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Abdo, Peter, and Angel Reyes-Cubas. "Simulation of Ventilation Flow Through a Room Fitted With a Windcatcher Incorporating Phase Change Materials." In ASME 2020 Fluids Engineering Division Summer Meeting collocated with the ASME 2020 Heat Transfer Summer Conference and the ASME 2020 18th International Conference on Nanochannels, Microchannels, and Minichannels. American Society of Mechanical Engineers, 2020. http://dx.doi.org/10.1115/fedsm2020-20171.
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Abstract Natural ventilation is the process of supplying and removing air through an indoor space by natural means. Windcatcher has been used over centuries for providing natural ventilation using wind power, it is an effective passive method to provide healthy and comfortable indoor environment by decreasing moisture content in the air and reducing pollutants concentration effectively. The windcatcher’s function is based on the wind and on the stack effect resulting from temperature differences. Materials that change phase at certain temperature are frequently referred to as Phase Change Materials (PCMs). PCMs change from solid to liquid and vice versa. PCMs could be used in passive cooling systems and they are directly related to building energy efficiency. In this study air flow through a two-dimensional room fitted with a windcatcher and incorporated with phase change materials (PCMs) is simulated. The temperature change in the room implementing PCM is analyzed to monitor the PCMs’ performance. To achieve this, Ansys Fluent is used to simulate the temperature changes inside the room as well as the melting process of PCM. PCM is placed at the right and left walls of the room and at its bottom. Two cases have been considered (with and without PCM) and the average temperatures at three locations have been compared for an inlet velocity of 1 m/s and an inlet temperature of 302 K. The average temperature at 1.2 m high inside the room with PCM dropped by about 1–2 °C compared to that without PCM.
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Abdo, Peter, Rahil Taghipour, and B. P. Huynh. "Three Dimensional Simulation of the Effect of Windcatcher’s Inlet Shape." In ASME-JSME-KSME 2019 8th Joint Fluids Engineering Conference. American Society of Mechanical Engineers, 2019. http://dx.doi.org/10.1115/ajkfluids2019-5385.
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Abstract Windcatcher has been used over centuries for providing natural ventilation using wind power, it is an effective passive method to provide healthy and comfortable indoor environment. The windcatcher’s function is based on the wind and on the stack effect resulting from temperature differences. Generally, it is difficult for wind to change its direction, and enter a room through usual openings, the windcatcher is designed to overcome such problems since they have vertical columns to help channel wind down to the inside of a building. The efficiency of a windcatcher is maximized by applying special forms of opening and exit. The openings depend on the windcatcher’s location and on its cross sectional area and shape such as square, rectangular, hexagonal or circular. In this study the effect of the inlet design is investigated to achieve better air flow and increase the efficiency of windcatchers. To achieve this, CFD (computational fluid dynamics) tool is used to simulate the air flow in a three dimensional room fitted with a windcatcher based on the different inlet designs. The divergent inlet has captured the highest air flow with a difference of approximately 3% compared to the uniform inlet and 5% difference compared to the bulging-convergent inlet.
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Reyes-Cubas, Angel, and Peter Abdo. "Simulation of Ventilation Flow at Different Conditions Through a Two-Dimensional Room Incorporated With Phase Change Materials." In ASME 2020 International Mechanical Engineering Congress and Exposition. American Society of Mechanical Engineers, 2020. http://dx.doi.org/10.1115/imece2020-23407.
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Abstract Climate change and global warming have raised many concerns, highlighting the necessity to reduce energy consumption associated with the building sector. HVAC systems account to almost 40% of the building’s energy consumption. Natural ventilation is the process of supplying and removing air through an indoor space by natural means. Windcatchers have been used over centuries for providing natural ventilation using wind power. Moreover, it is an effective passive method to provide healthy and comfortable indoor environment by decreasing moisture content in the air and reducing pollutants concentration significantly. Materials that change phase at certain temperature are frequently referred to as Phase Change Materials (PCMs). Phase Change Materials, also known as Thermal Energy Storage (TES), are substances with high latent heat storage capacity which absorb or release the heat from or to the surrounding environment. PCMs could be used in passive cooling systems and they are directly related to building energy efficiency. This study investigates air flow through a windcatcher into a two-dimensional room incorporated with phase change materials (PCMs). The temperature change in the room implementing PCM is analyzed to monitor the PCMs’ performance. To achieve this, Computational Fluid Dynamics (CFD) tool is used to simulate the air flow through a two-dimensional standard room (3 m × 5 m) fitted with a windcatcher at its roof. Ansys Fluent is utilized to simulate and display the contours of temperature, liquid fraction, and velocity of both PCM and air. The energy model as well as the solidification and melting model are employed, and the K-Epsilon turbulence model is implemented. PCM is placed at the right and left walls of the room, as well as at its bottom. The inlet velocity ranges between 1 m/s and 7 m/s, simulating the average wind speeds in Sydney-Australia during summer [1]. Different inlet temperatures are used, specifically at 302 K and 310 K. The effect of the phase change material presence on the air flow pattern is also investigated.
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Hasib, Naimee, Junghyon Mun, and Yong X. Tao. "Performance Analysis of Two HVAC Systems for Zero Energy Research Laboratory, Denton, TX." In ASME 2013 International Mechanical Engineering Congress and Exposition. American Society of Mechanical Engineers, 2013. http://dx.doi.org/10.1115/imece2013-65660.
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HVAC (Heating, Ventilation & Air Conditioning) system is the most significant part of a building which directly associated with human comfort. Modern HVAC system optimizes all the parameters like temperature, humidity and indoor air quality to give the occupant the best comfort. Beside human comfort some other crucial factors like installation, maintenance & operational cost, efficiency, availability and controlling method of the system need to be taken into consideration. This paper covers the study and comparison among two different HVAC systems to achieve the goal of finding the better effective HVAC system in terms of human comfort, efficiency considering North Texas climate. In this paper; power consumption, human comfort & efficiency analysis is done for the existing WWHP & WAHP system (in UNT ZØE) using Energy Plus simulation software. Calibration of the simulation data of the existing system is done comparing with the real data. After the baseline model is calibrated, simulation for other HVAC systems like evaporative cooler (EC) is conducted. The comparison analysis of both the HVAC systems shows the better effective HVAC system in North Texas weather considering all the relevant issues and challenges. The result will make UNT Zero Energy lab more energy efficient and a standard model towards a sustainable green future.
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Zhang, Yunbo, and Tsz-Ho Kwok. "A Customer-to-Manufacturer Design Model for Custom Compression Casts." In ASME 2019 International Design Engineering Technical Conferences and Computers and Information in Engineering Conference. American Society of Mechanical Engineers, 2019. http://dx.doi.org/10.1115/detc2019-98043.
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Abstract This paper presents a computational framework for designing and optimizing custom compression casts/braces. Different from the conventional cast/brace design, our framework generates custom casts/braces with fitness, lightweight, and good ventilation. The computational pipeline is an end-to-end solution, directly from customer to the manufacturer, which starts from a 3D scanned human model represented by mesh and ends with the 3D printed cast/brace. Our interactive tools allows users to define and edit the 3D curves on the mesh surface, and trim the mesh surface to form the cast/brace shape using the curves. These tools are efficient and simple to use, and also they enable designing the custom casts/braces fitting to the given human body. In order to reduce the weight and improve the ventilation, we adopt the topology optimization (TO) method to optimize the cast/brace design. We extend the existing three-dimensional (3D) TO method to the mesh surface by simplifying the optimization problem to a 2D problem. Therefore, the efficiency of the TO computation is improved significantly. After the optimized cast/brace design is obtained on the mesh surface, a solid model is generated by our design interface and then sent to a 3D printer for fabrication. Simulation results show that our method can better re-disturb the stresses compared with the conventional 3D TO.
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Zafar, Muhammad Usman, Vincent Lee, Will Timms, Patrick Bounds, and Mesbah Uddin. "Effects of HVAC Settings and Windows Open or Close on the SARS-CoV-2 Virus Transmission Inside a Mass Transit System Bus." In ASME 2021 International Mechanical Engineering Congress and Exposition. American Society of Mechanical Engineers, 2021. http://dx.doi.org/10.1115/imece2021-71701.
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Abstract With the current outbreak of SARS-CoV-2, public transportation is a key area which must be investigated to ensure both passenger safety and efficiency of passenger transport to best serve the community and reduce environmental footprint. In this paper, the transport of the SARS-CoV-2 virus through human respiratory particles is examined using transient Computational Fluid Dynamics (CFD) simulations to determine the impacts different ventilation configurations on the probability of viral exposure. The motion of the viral particles was simulated first by solving for the flow field inside the bus using a proprietary Navier-Stokes finite-volume solver, RavenCFD by Corvid Technologies, and then using Lagrangian particle tracking (LPT) post processing techniques. The LPT methods used allowed for the injection of respiratory particles, according to distributions found in literature, which included sneezing, coughing, and speaking. To fully investigate the problem space the moving bus was modeled with the windows in various states of closure and with various HVAC configurations. In all scenarios, a volumetric Viral Mean Exposure Time (VMET), which considers the viral load calculations, was used to quantify the various exposure risk of all passengers on the bus. It was found that the most efficient ventilation system on a public transport bus was to keep the windows closed and HVAC of main cabin at maximum to minimize the viral exposure within the bus.
Reports on the topic "Ventilation – Efficiency – Simulation methods"
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J. Case and D. Buesch. Simulation of Ventilation Efficiency, Temperatures, and Relative Humidities in Emplacement Drifts at Yucca Mountain, Nevada, Using Monte Carlo and Composite Thermal-Pulse Methods. Office of Scientific and Technical Information (OSTI), April 2004. http://dx.doi.org/10.2172/837500.
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Lvov, Michael S., and Halyna V. Popova. Simulation technologies of virtual reality usage in the training of future ship navigators. [б. в.], February 2020. http://dx.doi.org/10.31812/123456789/3758.
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Research goal: the research is aimed at the theoretical substantiation of the application of virtual reality technology simulators and their features in higher maritime educational institutions. Research objectives: to determine the role and place of simulation technology in the educational process in the training of future ship navigators in order to form the professional competence of navigation. Object of research: professional training of future ship navigators in higher maritime educational institutions. Subject of research: simulation technologies of virtual reality as a component of the educational process at higher educational maritime establishments. Research methods used: theoretical methods containing the analysis of scientific sources; empirical methods involving study and observation of the educational process. Research results: the analysis of scientific publications allows to define the concept of virtual reality simulators, their application in the training of future navigators, their use for assessing the acquired professional competence of navigation. Main conclusions: introduction of simulation technologies of virtual reality in the educational process in higher maritime educational institutions increases the efficiency of education, promotes the development of professional thinking of students, enhances the quality of professional competence development.
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Birchmore, Roger. Medium-density Dwellings in Auckland and the Building Regulations. Unitec ePress, July 2018. http://dx.doi.org/10.34074/ocds.0822.
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National thermal standards have historically been set to minimise winter heating energy in detached houses. It is uncertain whether these standards are optimal for the increasing number of joined, medium-density dwellings when summer and winter conditions are considered. Using freely available software, annual heating energy use and summertime peak temperatures were calculated for a number of versions of detached and joined dwellings offering the same occupied volume and window areas. Initial results indicated that, as expected, the joined dwellings required less heating energy. The detached house exhibited a higher peak summertime temperature but a lower overall average daily temperature. Interventions such as changing insulation, glazing areas and ventilation were calculated to reduce summertime temperatures in the joined dwelling. Increasing ventilation provided the greatest improvement particularly during the sensitive sleeping hours. Changes to clauses H1 Energy Efficiency, G4 ventilation and G6 Airborne and Impact Sound are recommended if these early findings are confirmed in a more complex simulation.
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Lahav, Ori, Albert Heber, and David Broday. Elimination of emissions of ammonia and hydrogen sulfide from confined animal and feeding operations (CAFO) using an adsorption/liquid-redox process with biological regeneration. United States Department of Agriculture, March 2008. http://dx.doi.org/10.32747/2008.7695589.bard.
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The project was originally aimed at investigating and developing new efficient methods for cost effective removal of ammonia (NH₃) and hydrogen sulfide (H₂S) from Concentrated Animal Feeding Operations (CAFO), in particular broiler and laying houses (NH₃) and hog houses (H₂S). In both cases, the principal idea was to design and operate a dedicated air collection system that would be used for the treatment of the gases, and that would work independently from the general ventilation system. The advantages envisaged: (1) if collected at a point close to the source of generation, pollutants would arrive at the treatment system at higher concentrations; (2) the air in the vicinity of the animals would be cleaner, a fact that would promote animal growth rates; and (3) collection efficiency would be improved and adverse environmental impact reduced. For practical reasons, the project was divided in two: one effort concentrated on NH₃₍g₎ removal from chicken houses and another on H₂S₍g₎ removal from hog houses. NH₃₍g₎ removal: a novel approach was developed to reduce ammonia emissions from CAFOs in general, and poultry houses in particular. Air sucked by the dedicated air capturing system from close to the litter was shown to have NH₃₍g₎ concentrations an order of magnitude higher than at the vents of the ventilation system. The NH₃₍g₎ rich waste air was conveyed to an acidic (0<pH<~5) bubble column reactor where NH₃ was converted to NH₄⁺. The reactor operated in batch mode, starting at pH 0 and was switched to a new acidic absorption solution just before NH₃₍g₎ breakthrough occurred, at pH ~5. Experiments with a wide range of NH₃₍g₎ concentrations showed that the absorption efficiency was practically 100% throughout the process as long as the face velocity was below 4 cm/s. The potential advantages of the method include high absorption efficiency, lower NH₃₍g₎ concentrations in the vicinity of the birds, generation of a valuable product and the separation between the ventilation and ammonia treatment systems. A small scale pilot operation conducted for 5 weeks in a broiler house showed the approach to be technically feasible. H₂S₍g₎ removal: The main goal of this part was to develop a specific treatment process for minimizing H₂S₍g₎ emissions from hog houses. The proposed process consists of three units: In the 1ˢᵗ H₂S₍g₎ is absorbed into an acidic (pH<2) ferric iron solution and oxidized by Fe(III) to S⁰ in a bubble column reactor. In parallel, Fe(III) is reduced to Fe(II). In the 2ⁿᵈ unit Fe(II) is bio-oxidized back to Fe(III) by Acidithiobacillus ferrooxidans (AF).In the 3ʳᵈ unit S⁰ is separated from solution in a gravity settler. The work focused on three sub-processes: the kinetics of H₂S absorption into a ferric solution at low pH, the kinetics of Fe²⁺ oxidation by AF and the factors that affect ferric iron precipitation (a main obstacle for a continuous operation of the process) under the operational conditions. H₂S removal efficiency was found higher at a higher Fe(III) concentration and also higher for higher H₂S₍g₎ concentrations and lower flow rates of the treated air. The rate limiting step of the H₂S reactive absorption was found to be the chemical reaction rather than the transition from gas to liquid phase. H₂S₍g₎ removal efficiency of >95% was recorded with Fe(III) concentration of 9 g/L using typical AFO air compositions. The 2ⁿᵈ part of the work focused on kinetics of Fe(II) oxidation by AF. A new lab technique was developed for determining the kinetic equation and kinetic parameters (KS, Kₚ and mₘₐₓ) for the bacteria. The 3ʳᵈ part focused on iron oxide precipitation under the operational conditions. It was found that at lower pH (1.5) jarosite accumulation is slower and that the performance of the AF at this pH was sufficient for successive operation of the proposed process at the H₂S fluxes predicted from AFOs. A laboratory-scale test was carried out at Purdue University on the use of the integrated system for simultaneous hydrogen sulfide removal from a H₂S bubble column filled with ferric sulfate solution and biological regeneration of ferric ions in a packed column immobilized with enriched AFbacteria. Results demonstrated the technical feasibility of the integrated system for H₂S removal and simultaneous biological regeneration of Fe(III) for potential continuous treatment of H₂S released from CAFO. NH₃ and H₂S gradient measurements at egg layer and swine barns were conducted in winter and summer at Purdue. Results showed high potential to concentrate NH₃ and H₂S in hog buildings, and NH₃ in layer houses. H₂S emissions from layer houses were too low for a significant gradient. An NH₃ capturing system was designed and tested in a 100-chicken broiler room. Five bell-type collecting devices were installed over the litter to collect NH₃ emissions. While the air extraction system moved only 10% of the total room ventilation airflow rate, the fraction of total ammonia removed was 18%, because of the higher concentration air taken from near the litter. The system demonstrated the potential to reduce emissions from broiler facilities and to concentrate the NH₃ effluent for use in an emission control system. In summary, the project laid a solid foundation for the implementation of both processes, and also resulted in a significant scientific contribution related to AF kinetic studies and ferrous analytical measurements.
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Shani, Uri, Lynn Dudley, Alon Ben-Gal, Menachem Moshelion, and Yajun Wu. Root Conductance, Root-soil Interface Water Potential, Water and Ion Channel Function, and Tissue Expression Profile as Affected by Environmental Conditions. United States Department of Agriculture, October 2007. http://dx.doi.org/10.32747/2007.7592119.bard.
Full textAbstract:
Constraints on water resources and the environment necessitate more efficient use of water. The key to efficient management is an understanding of the physical and physiological processes occurring in the soil-root hydraulic continuum.While both soil and plant leaf water potentials are well understood, modeled and measured, the root-soil interface where actual uptake processes occur has not been sufficiently studied. The water potential at the root-soil interface (yᵣₒₒₜ), determined by environmental conditions and by soil and plant hydraulic properties, serves as a boundary value in soil and plant uptake equations. In this work, we propose to 1) refine and implement a method for measuring yᵣₒₒₜ; 2) measure yᵣₒₒₜ, water uptake and root hydraulic conductivity for wild type tomato and Arabidopsis under varied q, K⁺, Na⁺ and Cl⁻ levels in the root zone; 3) verify the role of MIPs and ion channels response to q, K⁺ and Na⁺ levels in Arabidopsis and tomato; 4) study the relationships between yᵣₒₒₜ and root hydraulic conductivity for various crops representing important botanical and agricultural species, under conditions of varying soil types, water contents and salinity; and 5) integrate the above to water uptake term(s) to be implemented in models. We have made significant progress toward establishing the efficacy of the emittensiometer and on the molecular biology studies. We have added an additional method for measuring ψᵣₒₒₜ. High-frequency water application through the water source while the plant emerges and becomes established encourages roots to develop towards and into the water source itself. The yᵣₒₒₜ and yₛₒᵢₗ values reflected wetting and drying processes in the rhizosphere and in the bulk soil. Thus, yᵣₒₒₜ can be manipulated by changing irrigation level and frequency. An important and surprising finding resulting from the current research is the obtained yᵣₒₒₜ value. The yᵣₒₒₜ measured using the three different methods: emittensiometer, micro-tensiometer and MRI imaging in both sunflower, tomato and corn plants fell in the same range and were higher by one to three orders of magnitude from the values of -600 to -15,000 cm suggested in the literature. We have added additional information on the regulation of aquaporins and transporters at the transcript and protein levels, particularly under stress. Our preliminary results show that overexpression of one aquaporin gene in tomato dramatically increases its transpiration level (unpublished results). Based on this information, we started screening mutants for other aquaporin genes. During the feasibility testing year, we identified homozygous mutants for eight aquaporin genes, including six mutants for five of the PIP2 genes. Including the homozygous mutants directly available at the ABRC seed stock center, we now have mutants for 11 of the 19 aquaporin genes of interest. Currently, we are screening mutants for other aquaporin genes and ion transporter genes. Understanding plant water uptake under stress is essential for the further advancement of molecular plant stress tolerance work as well as for efficient use of water in agriculture. Virtually all of Israel’s agriculture and about 40% of US agriculture is made possible by irrigation. Both countries face increasing risk of water shortages as urban requirements grow. Both countries will have to find methods of protecting the soil resource while conserving water resources—goals that appear to be in direct conflict. The climate-plant-soil-water system is nonlinear with many feedback mechanisms. Conceptual plant uptake and growth models and mechanism-based computer-simulation models will be valuable tools in developing irrigation regimes and methods that maximize the efficiency of agricultural water. This proposal will contribute to the development of these models by providing critical information on water extraction by the plant that will result in improved predictions of both water requirements and crop yields. Plant water use and plant response to environmental conditions cannot possibly be understood by using the tools and language of a single scientific discipline. This proposal links the disciplines of soil physics and soil physical chemistry with plant physiology and molecular biology in order to correctly treat and understand the soil-plant interface in terms of integrated comprehension. Results from the project will contribute to a mechanistic understanding of the SPAC and will inspire continued multidisciplinary research.