Journal articles on the topic 'Ventilation – Efficiency – Simulation methods'
To see the other types of publications on this topic, follow the link: Ventilation – Efficiency – Simulation methods.
Create a spot-on reference in APA, MLA, Chicago, Harvard, and other styles
Consult the top 50 journal articles for your research on the topic 'Ventilation – Efficiency – Simulation methods.'
Next to every source in the list of references, there is an 'Add to bibliography' button. Press on it, and we will generate automatically the bibliographic reference to the chosen work in the citation style you need: APA, MLA, Harvard, Chicago, Vancouver, etc.
You can also download the full text of the academic publication as pdf and read online its abstract whenever available in the metadata.
Browse journal articles on a wide variety of disciplines and organise your bibliography correctly.
1
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.
Full textAbstract:
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.
2
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.
Full textAbstract:
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.
3
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.
Full textAbstract:
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.
4
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.
Full textAbstract:
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.
5
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.
Full textAbstract:
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.
6
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.
Full textAbstract:
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.
7
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.
Full textAbstract:
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.
8
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.
Full textAbstract:
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.
9
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.
Full textAbstract:
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.
10
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.
Full textAbstract:
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.
11
Krumins, Andris, Kristina Lebedeva, Antra Tamane, and Renars Millers. "Possibilities of Balancing Buildings Energy Demand for Increasing Energy Efficiency in Latvia." Environmental and Climate Technologies 26, no. 1 (January 1, 2022): 98–114. http://dx.doi.org/10.2478/rtuect-2022-0009.
Full textAbstract:
Abstract Nowadays national and international directives have focused on improving energy efficiency in the building sector. According to them, energy consumption and emissions of buildings must be reduced. This can be achieved by balancing energy demand in buildings. In this context, this paper proposes a buildings’ energy demand balancing method using the building energy consumption simulation program IDA ICE and real measurements. A 3D model of the building was developed, energy consumption and indoor climate of the building was monitored throughout the year, the behaviour of the occupants (a survey was conducted) was analysed, dynamic change of the weather was studied and all data were integrated into IDA ICE simulation. In order to increase the energy efficiency of buildings, the possibilities of optimization of heat production equipment and heating devices, as well as inspecting and optimization of ventilation and cooling equipment were considered. By adjusting the parameters of the heating system of the researched object, the energy consumption of the auto centre decreased to 39.3 kWh/m2 per year. One of the most popular methods of balancing energy demand in recent years – the creation of smart grids – is also considered.
12
Chen, Hong, En Dong Wang, and Qiong Li. "Towards the Climate Adaptive Residential Buildings Design." Applied Mechanics and Materials 193-194 (August 2012): 40–44. http://dx.doi.org/10.4028/www.scientific.net/amm.193-194.40.
Full textAbstract:
Climate adaptability of residential buildings is critical for their energy efficiency. This paper investigates the operable design methods dealing with residential climate adaptability on the basis of the general design principle and the conceptual design theory. Particularly, the impacts of wind forces on the ventilation environment and sunshine on the lighting environment for residential buildings are explored by combining qualitative analysis and numerical simulation under the perspectives of master plan and individual design, respectively. The corresponding alternative operable design schemes are presented through case examples to make buildings more adaptive to local climate.
13
Pham, Hong-Tham T., Aleksey K. Solovyev, and Sergey S. Korneev. "A field study on effects of openings on thermal performance of natural cooling efficiency for atrium buildings." Vestnik MGSU, no. 2 (February 2022): 149–58. http://dx.doi.org/10.22227/1997-0935.2022.2.149-158.
Full textAbstract:
Introduction. In this paper, we investigate the temperature stratification of buoyancy-driven natural ventilation of the atrium of building at ULK-MGSU through field experiments. The process of ventilation with different openings ratios in the translucent roofing and ground floor entrance doors are analyzed to reveal the physical insights. With this aim, the main focus of the study is to consider the temperature fields during cooling the atrium premises that increase the thermal performance of the administrative building at ULK in the summer. An expensive ventilation solution by the optimum design of the inlet-to-outlet opening area ratio in the translucent roofing covering is utilized to improve thermal comfort without reducing the level of illumination.
Materials and methods. In this study, field measurements were applied to investigate and compares temperature stratification by floors of naturally ventilated ULK atrium building with different outlet sizes and locations under hot period conditions. The results of field measurement was utilized to develop the baseline model for the computational fluid dynamics (CFD) simulation in future work.
Results. These results reveal that the sizes and locations of openings in the atrium building affect on modification of the indoor thermal condition. Moreover, energy efficiency is improved thanks to buoyancy-driven changes in air flow rate in an atrium with multiple openings.
Conclusions. This study shows that it can be possible reduce indoor air temperatures by 5 °C during the summer period. In addition to the large inlet openings at different atrium levels, a high ratio of the outlet opening area (>10 %) is recommended. The existing atrium of the building was opened 5 % of the total top-glass roof area, which helps to improve the performance of buoyancy-driven ventilation in order to achieve better atrium cooling performance and prevent the detrimental reverse air movement.
14
Zhao, Weixin, Panu Mustakallio, Sami Lestinen, Simo Kilpeläinen, Juha Jokisalo, and Risto Kosonen. "Numerical and Experimental Study on the Indoor Climate in a Classroom with Mixing and Displacement Air Distribution Methods." Buildings 12, no. 9 (August 27, 2022): 1314. http://dx.doi.org/10.3390/buildings12091314.
Full textAbstract:
One main challenge of air distribution in classrooms is to guarantee ventilation performance under different usage conditions. In this study, the indoor climate in summer and winter conditions with different occupancy densities in the classroom is presented. Thermal condition measurements of a half-size classroom were performed in a test room with four air suppliers: wall-grilles, ceiling diffusers, perforated duct diffusers, and displacement ventilation. Those measured data were used for CFD validation of the whole classroom. With CFD simulations, indoor climate parameters with different air diffusers are compared in summer and winter conditions. The results show that displacement ventilation gives the best performance in the occupied zone. The air change efficiency can be reached with displacement ventilation of 1.4 and of only 1 with the other three air diffusers. The air velocities were reasonably low (<0.3 m/s), and the indoor was quite uniform with ceiling diffusers, which is another well-performing solution for classrooms. Corridor wall-grilles give uniform thermal conditions but can have high velocities (0.4 m/s) on the perimeter side of the room space. The air distribution from the perforated duct diffuser is unstable, which causes high local draft (over 20%) in the occupied zone.
15
Uciu, Felicia, Tiberiu Catalina, Andreea Vartires, and Iolanda Colda. "Impact of Nocturnal Natural Ventilation On the Energy Consumption of Buildings." Mathematical Modelling in Civil Engineering 13, no. 2 (June 27, 2017): 17–26. http://dx.doi.org/10.1515/mmce-2017-0005.
Full textAbstract:
Abstract The analysis presented in this paper is dealing with the correct and energy efficient measures of cooling buildings through nocturnal natural ventilation. Using this solution is proved in this article to be efficient and can reduce substantially the cooling demand. In order to establish the factors influencing the process of passively cooling a building (the ventilation volume, exterior temperature, thermal capacity of the building, possible duration of the ventilation), we have chosen different buildings, which we have placed them in different temperature zones of Romania. The study is based on multiple simulations realized with a time step of one hour, with the following variations: the climatic parameters, the thermal characteristics of the building, the air flow during night time, the proposed interior temperature. Since the study consisted of numerous simulations, in order to treat the results we have used statistical methods that cover the practical and possible situations, and proved the efficiency of nocturnal ventilation.
16
Zhao, Wenxuan, Wei Ye, Qianru Zhang, and Xu Zhang. "Simulations on arrangements of induced jet-fans as auxiliary ventilation for a mechanical ventilated space with openings." E3S Web of Conferences 111 (2019): 01036. http://dx.doi.org/10.1051/e3sconf/201911101036.
Full textAbstract:
Underground garages, indoor stadiums, or more commonly used seagoing ships, can be used as large multi-purpose spaces, which are suitable for the carriage of a wide range of cargoes, as well as evacuation of people at overseas. The indoor environment in a multi-purpose cabin usually varies, in terms of pollutant emissions, hazardous levels and the corresponding ventilation requirements. A possible solution, in addition to a single regular HVAC system, is to use multiple induced jet fans. However, to pre-determine a universal design of fans, e.g., numbers, locations, directions, angles and flowrates, etc., may not be practical. In this preliminary work, methods to design the auxiliary ventilation system were discussed. The heat sources are located in the four corners on the floor. CFD method is used to further study the effects of six regular and four irregular arrangements of a 2×2 array of fans on local heat dilution with or without natural ventilation (e.g., additional openings in the space). Heat exhaust efficiency is used to evaluate the effects of different arrangements of fans on local heat dilution. The results show that adjustable ventilation using induced fans would be useful to provide various airflow distribution for a large space and the dilution of the heat can be improved and the areas of high temperature inside the space can be reduced. Furthermore, the heat exhaust efficiency would be higher and the induced fans have a more significant effect, especially when additional natural ventilation is available.
17
Shaptala, V., E. Hukalenko, N. Severin, and Y. Gusev. "FEATURES OF VENTILATION OF ARC WELDING WORKPLACES IN SMALL ROOMS." Bulletin of Belgorod State Technological University named after. V. G. Shukhov 7, no. 1 (January 18, 2022): 51–59. http://dx.doi.org/10.34031/2071-7318-2021-7-1-51-59.
Full textAbstract:
It is proposed to consider the device of an integrated ventilation system that combines local exhaust ventilation of welders' workplaces and general ventilation of premises as the main direction of normalizing the parameters of the air environment when performing arc welding. When organizing ventilation of welding rooms of limited dimensions, it is necessary to have the possible effect of drift flows. It increases as a result of the joint operation of exhaust devices. The effectiveness of devices for local exhaust ventilation of welding posts is analyzed. It depends on the space-planning solutions, the relative position of the supply and exhaust devices, as well as the peculiarities of performing technological operations. For a specific example of a welding room, an optimal variant of the organization of ventilation of welding stations is found. The fields of air mobility, its temperature and concentration of harmful impurities have been calculated by the computer modeling. The factors influencing its efficiency are revealed and the combinations of influencing factors providing the maximum permissible concentration of harmful emissions in the working zones of welders are established. The conditions have been determined under which the general exchange effect of local suction is sufficient to maintain the concentration in the room at the MPC level. The results obtained can be used to develop engineering methods for calculating and optimizing ventilation devices and systems, to analyze structural and design solutions for the ventilation of electric welding industries. Investigations of the processes of propagation of welding aerosols in the production area are carried out by means of experimental measurements, as well as computer simulation using the Ansys Fluent software hydrodynamic package.
18
Sinchuk, I., I. Peresunko, and A. Somochkyn. "MODEL STUDIES WITH IDENTIFICATION OF ENERGY EFFICIENT MODES OF FUNCTIONING OF MAIN FAN UNITS." Electromechanical and energy saving systems 2, no. 53 (2021): 40–46. http://dx.doi.org/10.30929/2072-2052.2021.2.54.40-46.
Full textAbstract:
Purpose. The paper analyzes the system and methods of starting synchronous electric motors of fans of the main ventilation of iron ore mines. It is concluded that it is necessary to modernize the method of starting a synchronous electric motor, despite the fact that the installed direct start-up system has a number of disadvantages, and negatively affects the energy indicators of the electromechanical complex of the main ventilation fan of mines. The priority direction in solving the complex of the above problems is the use of modern achievements in the field of semiconductor conversion technology, in terms of the development of effective circuits and methods for starting and controlling a synchronous electric drive. Originality. The method of separate regulation of size and frequency of output voltage of the multilevel converter of a clock at quasi-frequency start of the synchronous electric drive is offered, limits admissible values of starting currents to admissible values. Methodology. Simulation of transient processes of starting a synchronous electric motor with step-by-step changes in voltage and frequency of supply, which made it possible to determine the energy efficiency of this method. Result. A new method of starting with a step-by-step change in the voltage and frequency of a synchronous motor is proposed. The modeling of the proposed starting method for a synchronous electric motor with a fan torque on the motor shaft was carried out, while it allowed to get rid of the main drawback, namely, a large starting current and made it possible to increase the energy efficiency of the electromechanical complex of the main ventilation fans due to the fact that the consumed active energy during start-up will decrease approximately 50% compared to a direct starting system. Practical value. The proposed method and the obtained results of the study made it possible to prove that the effectiveness of the proposed method is very high and this will save most of the electrical energy when starting the fans of the main ventilation of iron ore mines. Figures 15, references 15
19
Panraluk, Chorpech, and Atch Sreshthaputra. "Development of guidelines for enhancement of thermal comfort and energy efficiency during winter for Thailand’s senior centers using surveys and computer simulation." Nakhara : Journal of Environmental Design and Planning 19 (December 31, 2020): 79–96. http://dx.doi.org/10.54028/nj2020197996.
Full textAbstract:
The objective of this study is to develop guidelines for thermal comfort and energy efficiency for senior centers during winter. The study was conducted in Phitsanulok, Thailand and it applied 3 study’s methods; field survey, laboratory study, and simulation in scSTREAM–a CFD program and DOE-2 program; to develop the guidelines. With a temperature set-point at 25.0°C in the existing air-conditioned senior centers, the study shows that occupants feel "Slightly cool". These feeling can be adjusted to "Neutral" by applying natural ventilation and fans to generate air speed of 0.57–0.60 m/s during 8:00 AM–1:00 PM, and by setting the temperature set-point at 26.0°C with air speed of 0.10–0.26 m/s during 1:00 AM–4:00 PM. The guidelines can help reduce energy consumption by 23.0 % and can apply for senior centers.
20
Melnik, V. L., M. V. Khrebor, Yu I. Sylenko, V. K. Shevchenko, and P. M. Skrypnikov. "APPLICATION OF METHODS OF SIMULATION TRAINING AT THE DEPARTMENT OF POSTGRADUATE EDUCATION OF DENTISTS." Ukrainian Dental Almanac, no. 1 (March 6, 2019): 41–43. http://dx.doi.org/10.31718/2409-0255.1.2019.08.
Full textAbstract:
The aim is to analyze the peculiarities of emergency care to dental practitioners at the department of postgraduate education of dentistry doctors for improving the quality of manual skills of the doctor in an outpatient department. Within the framework of the program, pilot trainings are held in Poltava and Lviv on the following topics: assistance in sudden coronary and sudden cardiac death, assistance with acute cerebrovascular accident, help with hypertensive crises, help with cardiac asthma and pulmonary edema. The training is carried out according to the methodological design and it consists of the theoretical and practical part. The training is provided by a certified teacher at the regional training and training center at M.V. Sklifosovsky Poltava Regional Clinical Hospital. The optimal number of listeners is 10-12 people. On the theoretical part the teacher represents the purpose, the plan of the lesson and in the logical sequence the material is presented. The theoretical part is equipped with a multimedia presentation. In the process, the teacher defines the basic level of knowledge and skills of listeners. In the practical part, the teacher initially determines the level of possession of clinical skills of doctors, teaches work on dummies, models real, simple and accessible to perception simulation scenarios. Doctors have to solve the tasks and practice practical skills from basic resuscitation measures. At the same time, an important place is given to work in the team. On phantoms, elements of the resuscitation brigade are worked out when providing emergency care to a patient with a terminal state (cardiac arrest) using cardiac-pulmonary resuscitation techniques (CPR). At the same time, artificial ventilation of the lungs (ventilation of the lungs) with exhalation in the mouth or the nose (mask) in the area of the head of the phantom is carried out. The modeling of the air duct is then modeled. This verifies the correctness of the laryngoscope in the oropharynx, and the introduction of the laryngeal mask. Doctors will work with Ambu's bag: the first hand fix the mask of the device in the area of the nose, the mouth of the phantom, and the other - by pressing the camera, the air is poured into the roton-nose area of the phantom with a certain frequency of pressure, followed by the use (if necessary) of an oxygen cylinder of type B. This checks the correctness of each reception. Conducting each manual reception and its effectiveness is fixed and processed by a computer program. The result is displayed on the monitor in the form of vital signs of the patient. In the case of effective doctor actions, the vital parameters of the "patient" on the monitor are normalized. The evaluation of the effectiveness of the manipulations is also carried out in balls. In the beginning, the trainer-instructor shows the order and correctness of carrying out emergency assistance measures on phantoms. In the future, monitors the implementation of manual techniques and assesses the actions of interns at each individual stage, emphasizing the correct implementation of the manual action. The sequence of the manual training on the "phantom-monitor" system gives confidence to doctors in the correctness and efficiency of manual skills. At the end of the practical cycle of training certified teachers of the department summarize the practical training with doctors-dentists. Practical training with the use of modern phantoms with computer processing of results helps to increase the competence of dental practitioners in providing emergency care and to ensure the use of the knowledge to improve the quality of medical care for patients.
21
Majdi, Hasan Shakir, Mahmoud A. Mashkour, Laith Jaafer Habeeb, and Ahmad H. Sabry. "Enhancement of energy transfer efficiency for photovoltaic (PV) systems by cooling the panel surfaces." Eastern-European Journal of Enterprise Technologies 4, no. 8(112) (August 31, 2021): 83–89. http://dx.doi.org/10.15587/1729-4061.2021.238700.
Full textAbstract:
The thermal coefficient of a solar photovoltaic (PV) panel is a value that is provided with its specification sheet and tells us precisely the drop in panel performance with rising temperature. In desert climates, the PV panel temperatures are known to reach above 70 degrees centigrade. Exploring effective methods of increasing energy transfer efficiency is the issue that attracts researchers nowadays, which also contributes to reducing the cost of using solar photovoltaic (PV) systems with storage batteries. Temperature handling of solar PV modules is one of the techniques that improve the performance of such systems by cooling the bottom surface of the PV panels. This study initially reviews the effective methods of cooling the solar modules to select a proper, cost-effective, and easy to implement one. An active fan-based cooling method is considered in this research to make ventilation underneath the solar module. A portion of the output power at a prespecified high level of battery state-of-charge (SOC) is used to feed the fans. The developed comparator circuit is used to control the power ON/OFF of the fans. A Matlab-based simulation is employed to demonstrate the power rate improvements and that consumed by the fans. The results of simulations show that the presented approach can achieve significant improvements in the efficiency of PV systems that have storage batteries. The proposed method is demonstrated and evaluated for a 1.62 kW PV system. It is found from a simultaneous practical experiment on two identical PV panels of 180 W over a full day that the energy with the cooling system was 823.4 Wh, while that without cooling was 676 Wh. The adopted approach can play a role in enhancing energy sustainability.
22
Cojbasic, Zarko, Milan Ristanovic, Nemanja Markovic, and Stefan Tesanovic. "Temperature controller optimization by computational intelligence." Thermal Science 20, suppl. 5 (2016): 1541–52. http://dx.doi.org/10.2298/tsci16s5541c.
Full textAbstract:
In this paper a temperature control system for an automated educational classroom is optimized with several advanced computationally intelligent methods. Controller development and optimization has been based on developed and extensively tested mathematical and simulation model of the observed object. For the observed object cascade P-PI temperature controller has been designed and conventionally tuned. To improve performance and energy efficiency of the system, several metaheuristic optimizations of the controller have been attempted, namely genetic algorithm optimization, simulated annealing optimization, particle swarm optimization and ant colony optimization. Efficiency of the best results obtained with proposed computationally intelligent optimization methods has been compared with conventional controller tuning. Results presented in this paper demonstrate that heuristic optimization of advanced temperature controller can provide improved energy efficiency along with other performance improvements and improvements regarding equipment wear. Not only that presented methodology provides for determination and tuning of the core controller, but it also allows that advanced control concepts such as anti-windup controller gain are optimized simultaneously, which is of significant importance since interrelation of all control system parameters has important influence on the stability and performance of the system as a whole. Based on the results obtained, general conclusions are presented indicating that meta-heuristic computationally intelligent optimization of heating, ventilation, and air conditioning control systems is a feasible concept with strong potential in providing improved performance, comfort and energy efficiency.
23
Mahar, Waqas Ahmed, Griet Verbeeck, Manoj Kumar Singh, and Shady Attia. "An Investigation of Thermal Comfort of Houses in Dry and Semi-Arid Climates of Quetta, Pakistan." Sustainability 11, no. 19 (September 23, 2019): 5203. http://dx.doi.org/10.3390/su11195203.
Full textAbstract:
In Pakistan, reinforced concrete frame houses are the most widely used and common construction technology. In a country that experiences extreme hot and cold seasons throughout the year, buildings need to be adaptable to the climate to improve the thermal comfort of the inhabitants. Therefore, the aim of this study was to improve thermal comfort in reinforced concrete frame houses using passive design and energy efficiency measures in Quetta, Pakistan. Thermal comfort of a representative house was investigated using a building performance simulation. The building model created in EnergyPlus was validated by comparing it with on-site monitored data in both summer and winter seasons. The model was calibrated using statistical methods. Then, the calibrated model was used to perform a whole year simulation in which various orientations, ventilation, passive design, and energy efficiency strategies were applied to perform parametric analysis for the improvement of thermal comfort. The best fit-to-context thermal comfort model was selected, and the potential of bioclimatic design strategies was quantified. The results indicate that by adopting passive design strategies comfort hours can be increased from 43% to 59%. The results of the study revealed many findings which could be useful for architects and building engineers to set a future direction for improvement of indoor comfort in Quetta as well as in many other areas of Balochistan Province in Pakistan.
24
Wang, Shiqiang, Jianchun Xing, Ziyan Jiang, and Juelong Li. "A decentralized sensor fault detection and self-repair method for HVAC systems." Building Services Engineering Research and Technology 39, no. 6 (May 7, 2018): 667–78. http://dx.doi.org/10.1177/0143624418775881.
Full textAbstract:
This study proposes a novel decentralized sensor fault detection and self-repair method for heating, ventilation and air-conditioning systems. From the perspective of network structure, sensor fault diagnosis in heating, ventilation and air-conditioning systems is distributed to the updated smart sensors without the monitoring host, which is necessary in the traditional centralized method. A fully distributed flat sensor network is established based on fundamental physical equations. Similar to the structure, mechanism and characteristics of biological communities, a smart sensor needs only to communicate with adjacent nodes and operate collaboratively to complete sensor fault detection and self-repair tasks. These tasks are formulated as a constrained optimization and are solved by a decentralized algorithm with a penalty function executed in all the sensor nodes in parallel. The diagnosis model introduces an exponential function method to determine the precise location and undertake self-repair of a fault node. Simulation results on a chilled water system illustrate the effectiveness of the proposed method. Practical application: The traditional sensor fault detection and diagnosis methods for heating, ventilation and air-conditioning systems are based on a centralized structure with several deficiencies, such as high maintenance and labor costs, link congestion and operational lag. This study presents a decentralized sensor network structure and exponential-function-based method that possess the advantages of plug-and-play, rapid deployment, high flexibility and convenience for engineering implementation without having to build a central monitor. The efficiency and effectiveness of the proposed method are demonstrated via a case study.
25
Che, Jigang, Angui Li, Jiaxing Li, Jinnan Guo, and Hong Xu. "Theoretical Study on Unsteady Temperature Field and Heat Regulating Zone for Earth-air Heat Exchanger." E3S Web of Conferences 356 (2022): 01070. http://dx.doi.org/10.1051/e3sconf/202235601070.
Full textAbstract:
The earth-air heat exchanger (EAHE) play an important role in building energy efficiency. Most of the previous studies have adopted numerical simulation and experimental methods, and Theoretical research was rarely used. The theoretical analysis method has clear mathematical physical meaning. Due to the few theoretical analysis methods used, there were no general criteria for the value of heat-regulating zone. The inaccurate value of the heat regulating zone will cause calculation errors or waste unnecessary computing resources. In this research, the calculation formula of the unsteady temperature field of the EAHE was derived and the calculation correlation of value of the heat regulating zone was also given. The results show that the derived calculation formula of the unsteady the dimensionless airflow of EAHE is in good agreement with the experiment, and calculation correlation of the value of the heat regulating zone is suitable for various engineering. This research provides a theoretical basis for the design and application of tunnel ventilation and a correlation formula for the value of the heat regulating zone.
26
Parzinger, Michael, Lucia Hanfstaengl, Ferdinand Sigg, Uli Spindler, Ulrich Wellisch, and Markus Wirnsberger. "Residual Analysis of Predictive Modelling Data for Automated Fault Detection in Building’s Heating, Ventilation and Air Conditioning Systems." Sustainability 12, no. 17 (August 20, 2020): 6758. http://dx.doi.org/10.3390/su12176758.
Full textAbstract:
Faults in Heating, Ventilation and Air Conditioning (HVAC) systems affect the energy efficiency of buildings. To date, there rarely exist methods to detect and diagnose faults during the operation of buildings that are both cost-effective and sufficient accurate. This study presents a method that uses artificial intelligence to automate the detection of faults in HVAC systems. The automated fault detection is based on a residual analysis of the predicted total heating power and the actual total heating power using an algorithm that aims to find an optimal decision rule for the determination of faults. The data for this study was provided by a detailed simulation of a residential case study house. A machine learning model and an ARX model predict the building operation. The model for fault detection is trained on a fault-free data set and then tested with a faulty operation. The algorithm for an optimal decision rule uses various statistical tests of residual properties such as the Sign Test, the Turning Point Test, the Box-Pierce Test and the Bartels-Rank Test. The results show that it is possible to predict faults for both known faults and unknown faults. The challenge is to find the optimal algorithm to determine the best decision rules. In the outlook of this study, further methods are presented that aim to solve this challenge.
27
Roccotelli, Michele, Alessandro Rinaldi, Maria Pia Fanti, and Francesco Iannone. "Building Energy Management for Passive Cooling Based on Stochastic Occupants Behavior Evaluation." Energies 14, no. 1 (December 29, 2020): 138. http://dx.doi.org/10.3390/en14010138.
Full textAbstract:
The common approach to model occupants behaviors in buildings is deterministic and consists of assumptions based on predefined fixed schedules or rules. In contrast with the deterministic models, stochastic and agent based (AB) models are the most powerful and suitable methods for modeling complex systems as the human behavior. In this paper, a co-simulation architecture is proposed with the aim of modeling the occupant behavior in buildings by a stochastic-AB approach and implementing an intelligent Building Energy Management System (BEMS). In particular, optimized control logics are designed for smart passive cooling by controlling natural ventilation and solar shading systems to guarantee the thermal comfort conditions and maintain energy performance. Moreover, the effects of occupant actions on indoor thermal comfort are also taken into account. This study shows how the integration of automation systems and passive techniques increases the potentialities of passive cooling in buildings, integrating or replacing the conventional efficiency strategies.
28
Hu, Yue, Rui Guo, Per Kvols Heiselberg, and Hicham Johra. "Modeling PCM Phase Change Temperature and Hysteresis in Ventilation Cooling and Heating Applications." Energies 13, no. 23 (December 6, 2020): 6455. http://dx.doi.org/10.3390/en13236455.
Full textAbstract:
Applying phase change material (PCM) for latent heat storage in sustainable building systems has gained increasing attention. However, the nonlinear thermal properties of the material and the hysteresis between the two-phase change processes make the modelling of PCM challenging. Moreover, the influences of the PCM phase transition and hysteresis on the building thermal and energy performance have not been fully understood. This paper reviews the most commonly used modelling methods for PCM from the literature and discusses their advantages and disadvantages. A case study is carried out to examine the accuracy of those models in building simulation tools, including four methods to model the melting and freezing process of a PCM heat exchanger. These results are compared to experimental data of the heat transfer process in a PCM heat exchanger. That showed that the four modelling methods are all accurate for representing the thermal behavior of the PCM heat exchanger. The model with the DSC Cp method with hysteresis performs the best at predicting the heat transfer process in PCM in this case. The impacts of PCM phase change temperature and hysteresis on the building energy-saving potential and thermal comfort are analyzed in another case study, based on one modelling method from the first case study. The building in question is a three-room apartment with PCM-enhanced ventilated windows in Denmark. The study showed that the PCM hysteresis has a larger influence on the building energy consumption than the phase change temperature for both summer night cooling applications and for winter energy storage. However, it does not have a strong impact on the yearly total energy usage. For both summer and winter transition seasons, the PCM hysteresis has a larger influence on the predicted percentage of dissatisfied (PPD) than the phase change temperature, but not a strong impact on the transition season average PPD. It is therefore advised to choose the PCM hysteresis according to whether it is for a summer night cooling or a winter solar energy storage application, as this has a significant impact on the system’s overall efficiency.
29
Yang, Ye, and Zhenyu Li. "Integrated Design and Assessment for Indoor Heating, Ventilation and Air-Conditioning in Hot Summer and Cold Winter Area: A Case Study in China." Buildings 12, no. 11 (November 1, 2022): 1844. http://dx.doi.org/10.3390/buildings12111844.
Full textAbstract:
Integrated design of the heating, ventilation and air-conditioning (HVAC) is indispensable to green design because the increasing demand for HVAC systems has led to the diversification of indoor terminals for residential buildings, either focusing on energy efficiency or specializing in creating comfortable indoor environments, and they have different impacts on architectural and engineering design. The paper discussed the assessment-based integration design of the HVAC system, and by introducing case experiences, the whole process of the collaboration between architects and engineers was explored. Various methods were used in the research. The analytic hierarchy process (AHP) was employed to develop the assessment structure and calculate weightings; employing fuzzy comprehensive evaluation (FCE), the social performances of HVAC systems were subjectively evaluated; simulation technology was used to calculate the energy performances; the final results were ranked by the order of preference by similarity to ideal solution (TOPSIS). The research perspective of the collaboration between architects and engineers contributed to the existing literature. Besides, different indoor terminals were analyzed from the two disciplines; an assessment tool (ATI) was conducted and could be referred to; the current green building rating tools were analyzed, and suggestions were proposed to promote the integrated design.
30
Stecka, Anna M., Tomasz Gólczewski, Elżbieta M. Grabczak, Krzysztof Zieliński, Marcin Michnikowski, Monika Zielińska-Krawczyk, Piotr Korczyński, and Rafał Krenke. "The use of a virtual patient to follow changes in arterial blood gases associated with therapeutic thoracentesis." International Journal of Artificial Organs 41, no. 11 (August 24, 2018): 690–97. http://dx.doi.org/10.1177/0391398818793354.
Full textAbstract:
Purposes: Some controversies exist on the effect of therapeutic thoracentesis (TT) on arterial blood oxygen tension. The aim of this study was to evaluate this issue using a previously developed virtual patient. Methods: The analysis was based and supported by clinical data collected during 36 TT. Pleural pressure and transcutaneous oxygen and carbon dioxide pressures (PtcO2 and PtcCO2) were measured during pleural fluid withdrawal. Arterial blood oxygen tension and arterial CO2 tension (PaO2 and PaCO2) were analysed in simulations that mimicked TT. Minute ventilation was adjusted to maintain arterial CO2 tension at a constant level unless arterial blood oxygen tension fell below 8 kPa. Specifically, the influence of hypoxic pulmonary vasoconstriction efficiency was tested. Results: In patients, PtcCO2 remained at an approximately constant level (average amplitude: 0.63 ± 0.29 kPa), while some fluctuations of PtcO2 were observed (amplitude: (1.65 ± 1.18 kPa) were observed. In 42% of patients, TT was associated with decrease in PtcCO2. Simulations showed the following: (a) there were similar PaO2 fluctuations in the virtual patient; (b) the lower the hypoxic pulmonary vasoconstriction efficiency, the more pronounced the PaO2 fall during fluid withdrawal; and (c) the lower the atelectatic lung areas recruitment rate, the slower the PaO2 normalization. The decrease in PaO2 was caused by an increase of pulmonary shunt. Conclusion: Therapeutic thoracentesis may cause both an increase and a decrease in PaO2 during the procedure. Pleural pressure decrease, caused by pleural fluid withdrawal, improves the perfusion of atelectatic lung areas. If the rate of recruitment of these areas is low, a lack of ventilation causes the arterial blood oxygen tension to fall. Effective hypoxic pulmonary vasoconstriction may protect against the pulmonary shunt.
31
Fořt, Jan, Jiří Šál, Jan Kočí, and Robert Černý. "Energy Efficiency of Novel Interior Surface Layer with Improved Thermal Characteristics and Its Effect on Hygrothermal Performance of Contemporary Building Envelopes." Energies 13, no. 8 (April 17, 2020): 2012. http://dx.doi.org/10.3390/en13082012.
Full textAbstract:
Facing the consequences of climate change and fuel price rises, the achievement of the requirements for low-energy consumption of buildings has become a challenging issue. On top of that, increased demands on indoor hygrothermal conditions usually require the utilization of additional heating, ventilation, and air-conditioning (HVAC) systems to maintain a comfortable environment. On this account, several advanced and modern materials are widely investigated as a promising way for reduction of the buildings’ energy consumption including utilization of passive heating/cooling energy. However, the efficiency and suitability of passive strategies depending on several aspects including the influence of location, exterior climatic conditions, load-bearing materials used, and insulation materials applied. The main objective of this study consists of the investigation of the energy performance benefits gained by the utilization of advanced materials in plasters by computational modeling. Results obtained from a computational simulation reveal the capability of the studied passive cooling/heating methods on the moderation of indoor air quality together with the reduction of the diurnal temperature fluctuation. Achieved results disclose differences in terms of energy savings for even small variation in outdoor climate conditions. Additionally, the effectivity of passive cooling/heating alters considerably during the summer and winter periods. Based on the analysis of simulated heat fluxes, the potential energy savings related to improved thermal properties of the applied plaster layer reached up to 12.08% and thus represent an interesting passive solution towards energy sustainability to meet the criteria on modern buildings.
32
Есин, Владимир Михайлович, and Сергей Петрович Калмыков. "Justification of the smoke consumption removed from the floor corridors during a fire in high-rise buildings." Pozharnaia bezopasnost`, no. 3(108) (September 15, 2022): 76–85. http://dx.doi.org/10.37657/vniipo.pb.2022.46.16.009.
Full textAbstract:
Статистические данные показывают, что причиной гибели людей при пожарах в 80 % случаев являются дым и отравление токсичными продуктами горения. Система противодымной защиты - одна из подсистем активной противопожарной защиты зданий и сооружений. Область применения и состав систем регламентируются действующими нормативными документами. Одной из задач системы противодымной защиты является предотвращение выхода дыма из коридора в лестничную клетку и создание незадымленной зоны в нижней части коридора. Параметры вентиляционного оборудования систем противодымной защиты определяются расчетом. В настоящее время расчеты проводятся по методикам ВНИИПО или АВОК. Statistics show that 80 % of deaths in fires are caused by smoke and poisoning by toxic combustion products. The smoke protection system is one of the subsystems of active fire protection of buildings and structures. The scope and structure of the systems are regulated by the current regulatory documents. One of the tasks of the smoke protection system is to prevent smoke from escaping from the corridor to the stairwell and to create a smoke-free zone in the lower part of the corridor. The parameters of the ventilation equipment of smoke control systems are determined by calculation. At present, calculations are carried out according to the methods of FGBU VNIIPO EMERCOM of Russia or ABOK. Purposes. To confirm the smoke-free (smoky) nature of the protected spaces and to determine the optimal parameters of operation of the smoke exhaust system from the corridors, based on numerical experiments it is necessary to evaluate the operation of the exhaust smoke ventilation of the corridors at various values of the determining parameters. Research methods. The field (differential) model was used for calculations since the floor of the building equipped with a smoke ventilation system has a complex geometric shape. There was used the Fire Dynamics Simulator software package which implements the field model of a fire in a room during the numerical simulation. Results and discussion. The least value of smoke spreading in the corridor and the absence of smoke in the stairwell of type H2 is observed in the variant of ensuring the air flow rate through the open door from the stairwell to the corridor equal to 2,1 m/s and the flow rate of the removed combustion products equal to 2,31 kg/s. A similar picture is observed in all considered options, both with opened and not opened glazing of the opening of the fire seat room and with different distances between the fire seat room and the staircase. Conclusions. The conducted numerical experiments show and confirm the assumption about the violation of the balance of the costs of smoke removal from the corridor and the support of the stairwell. The consequence of this is the low efficiency of these systems which entails smoke in the protected volumes. The results of calculations allow identifying the variant of operation of the smoke exhaust system from the corridors and the backwater system in the H2 type stairwell with the highest efficiency. This is the option when the air flow rate through the doorway is 2,1 m/s, and the smoke exhaust flow rate corresponds to the air flow rate from the staircase to the corridor. To carry out practical calculations including according to existing methods for the effective operation of the smoke exhaust system from the corridors and the backwater system in the H2 type stairwell, it is necessary to take inflow and smoke exhaust costs corresponding to the “Recommendations for the calculation of ventilation systems for smoke protection of residential buildings with increased number of storeys”.
33
Lee, Haksung, Akihito Ozaki, Younhee Choi, and Muhammad Iqbal. "Performance Improvement Plan of Air Circulation-Type Solar Heat-Storage System Using Ventilated Cavity of Roof." Energies 14, no. 6 (March 14, 2021): 1606. http://dx.doi.org/10.3390/en14061606.
Full textAbstract:
Indoor solar-heating systems that use ventilated roofs have drawn attention in recent years. The effectiveness and efficiency of such air-heating systems vary depending on the design and operation methods. In Japan, by introducing outside air into a ventilated roof cavity and circulating the air indoors, systems that simultaneously obtain ventilation, solar heating, and heat-storage effects have been actively developed. The conventional systems intake a large volume of outside air to increase the solar heat collection effect. However, there is a risk of heat loss and over-drying when a large amount of cold dry air during winter is introduced. In this paper, plans are presented for improving these solar heating and heat-storage effects by preventing over-drying using indoor air circulation via ventilated cavities in the roof and indoor wall. By comparing the results of the proposed system with those of the conventional system via numerical simulation, the heating load is found to be reduced by 50% or more by circulating indoor air to the ventilated roof and storing the heat in the indoor wall. Moreover, an increased relative humidity of approximately 10% was confirmed by reducing the intrusion of the outside air and keeping the moisture indoors.
34
Becchio, Cristina, Marta Carla Bottero, Stefano Paolo Corgnati, Federico Dell’Anna, Valentina Fabi, Carola Lingua, Leonardo Prendin, and Micaela Ranieri. "The effects of indoor and outdoor air pollutants on workers’ productivity in office building." E3S Web of Conferences 111 (2019): 02057. http://dx.doi.org/10.1051/e3sconf/201911102057.
Full textAbstract:
In the present-day society, people spend about 80% of their time inside buildings, and specifically 30-40% in workplaces. From this evidence, the indoor environmental quality needs to be investigated, and in particular, the possible sources of indoor-outdoor pollutants and their impact on the human health, comfort and productivity. First, through an examination of the indoor sources of pollution, the research analysed the main substances that affect indoor air quality in an office. Second, the pollution of external origin and its effects on the performance of employees were taken into consideration. Two scenarios were designed for a Heating Ventilation Air Conditioning (HVAC) system in an office building; one by the installation of a biocidal filter and the other by a traditional one. Two methods were applied to evaluate and compare those scenarios; the Cost Benefit Analysis and the Monte Carlo Simulation. From a financial point of view, the investment and management costs of the filters were considered. Instead, the annual benefits included increasing productivity and reducing days of absence from work due to illness. The results confirmed the energy and socio-economic efficiency of the antibacterial filter; it can be considered a solution to achieve the best income.
35
Shchetinin, E. Yu. "ENERGY SAVING TECHNOLOGIES IN POWER SUPPLY OF SMART BUILDINGS USING ARTIFICIAL INTELLIGENCE." Vestnik komp'iuternykh i informatsionnykh tekhnologii, no. 194 (August 2020): 29–37. http://dx.doi.org/10.14489/vkit.2020.08.pp.029-037.
Full textAbstract:
Intelligent energy saving and energy efficiency technologies are the modern large-scale global trend in the energy systems development. The demand for smart buildings is growing not only in the world, but also in Russia, especially in the market of construction and operation of large business centers, shopping centers and other business projects. Accurate cost estimates are important for promoting energy efficiency construction projects and demonstrating their economic attractiveness. The growing number of digital measurement infrastructure, used in commercial buildings, led to increase access to high-frequency data that can be used for anomaly detection and diagnostics of equipment, heating, ventilation, and optimization of air conditioning. This led to the use of modern and efficient machine learning methods that provide promising opportunities to obtain more accurate forecasts of energy consumption of the buildings, and thus increase energy efficiency. In this paper, based on the gradient boosting model, a method of modeling and forecasting the energy consumption of buildings is proposed and computer algorithms are developed to implement it. Energy consumption dataset of 300 commercial buildings was used to assess the effectiveness of the proposed algorithms. Computer simulations showed that the use of these algorithms has increased the accuracy of the prediction of energy consumptionin more than 80 percent of cases compared to other machine learning algorithms.
36
Shchetinin, E. Yu. "ENERGY SAVING TECHNOLOGIES IN POWER SUPPLY OF SMART BUILDINGS USING ARTIFICIAL INTELLIGENCE." Vestnik komp'iuternykh i informatsionnykh tekhnologii, no. 194 (August 2020): 29–37. http://dx.doi.org/10.14489/vkit.2020.08.pp.029-037.
Full textAbstract:
Intelligent energy saving and energy efficiency technologies are the modern large-scale global trend in the energy systems development. The demand for smart buildings is growing not only in the world, but also in Russia, especially in the market of construction and operation of large business centers, shopping centers and other business projects. Accurate cost estimates are important for promoting energy efficiency construction projects and demonstrating their economic attractiveness. The growing number of digital measurement infrastructure, used in commercial buildings, led to increase access to high-frequency data that can be used for anomaly detection and diagnostics of equipment, heating, ventilation, and optimization of air conditioning. This led to the use of modern and efficient machine learning methods that provide promising opportunities to obtain more accurate forecasts of energy consumption of the buildings, and thus increase energy efficiency. In this paper, based on the gradient boosting model, a method of modeling and forecasting the energy consumption of buildings is proposed and computer algorithms are developed to implement it. Energy consumption dataset of 300 commercial buildings was used to assess the effectiveness of the proposed algorithms. Computer simulations showed that the use of these algorithms has increased the accuracy of the prediction of energy consumptionin more than 80 percent of cases compared to other machine learning algorithms.
37
Seidabadi, Leila, Hossein Ghadamian, and Mohammad Aminy. "A Novel Integration of PCM with Wind-Catcher Skin Material in Order to Increase Heat Transfer Rate." International Journal of Renewable Energy Development 8, no. 1 (February 2, 2019): 1. http://dx.doi.org/10.14710/ijred.8.1.1-6.
Full textAbstract:
In this research, a comprehensive simulation study including 3-D Dynamic time-dependent has been performed for Phase Change Materials (PCMs) applicant as a thermal storage integrated with the wind-catcher-wall in order to reduce the temperature difference (As a sustainable cooling method) in the MATLAB open-source–code software. By means of 3-D Dynamic time-dependent, as a final finding, the temperature drop (Cooling purpose) was obtained 25 degrees at about 7 working hours. Passive cooling can be considered as a viable and attractive strategy for the sustainable concept, opposed to mitigation of energy consumption and Green House Gas (GHG) simultaneously. One of the traditional-old-age famous passive cooling systems that are still being applied nowadays is wind-catcher as an energy system. The wind catcher sustain natural ventilation and cooling in buildings through wind-driven airflow as well as temperature difference. Windcatchers can save the electrical energy used to provide thermal comfort during the hot climate in summer case of the year, especially during the peak hours contributed to energy carriers’ consumptions. In this study, by proposing a new design of the windcatchers, attempts have been made to improve the energy efficiency of passive cooling methods. Besides, the application of new efficient methods for the purpose of thermal energy storage (PCM) as a sub-system is a chosen method to increase energy efficiency. By applying energy storage systems in addition to increase system energy performance and reliability, the target of reducing energy consumption is achieved.© 2019. CBIORE-IJRED. All rights reservedArticle History: Received May 18th 2018; Received in revised form October 5th 2018; Accepted January 5th 2019; Available onlineHow to Cite This Article: Seidabadi, L., Ghadamian, H, and Aminy, M. (2019) A Novel Integration of PCM with Wind-Catcher Skin Material in Order to Increase Heat Transfer Rate. Int. Journal of Renewable Energy Development, 8(1), 1-6.https://doi.org/10.14710/ijred.8.1.1-6
38
Fedoriachenko, Serhii, Kyrylo Ziborov, Roman Dzhur, and Anton Kholodov. "Calculation of upper support shafts cooling system parameters by means of the finite element method." Bulletin of Kharkov National Automobile and Highway University, no. 99 (December 29, 2022): 92. http://dx.doi.org/10.30977/bul.2219-5548.2022.99.0.92.
Full textAbstract:
Problem. The paper proposes a method for solving the problem of the temperature regimes of the upper support shafts using the finite element method. Thus, using the experimentally obtained values of the cooling air flow of the shafts, the possibility of using the State Thermal module of the Ansys software for a multi-iteration study of the temperature distribution and determining the ranges of thermal expansion was considered. It is an important task during engineering tasks solution. Goal. The goal of the paper is to develop a methodology to solve thermal exchange tasks using FEA methods based on the experiment research of the thermal processes. Methodology. Solution of the tasks involved application of the theoretical approach in order to build up multi-purpose solid models with the range of initial data to provide a simulation research. Results. The proposed method allows to determine the efficiency of the cooling system in a wide range of changes in air flow parameters and the compliance of the established thermal clearances of the bearing assemblies. Originality. Engineering tasks of the denoted area are rarely solved with FEA, especially thermal package. Thus, implementation of the software with experimental research kit allows in timely manner check the thermal state of the shafts and indicate possible cooling air leaks at the very first stage to avoid time consuming technical service. Practical value. The use of the denoted methodology allows to adjust cooling system in terms of sufficient shaft thermal state of bearing clearances and keep updated cooling parameters to maneuver the main ventilation system.
39
Hatta, Muhammad, and Hwataik Han. "Comparison of performance of heat recovery ventilator and air purifier in reducing indoor PM10 concentrations in a classroom." E3S Web of Conferences 111 (2019): 06065. http://dx.doi.org/10.1051/e3sconf/201911106065.
Full textAbstract:
Recently, outdoor particulate matters have become a serious problem in Korea. Pollutants exhausted from industrial plants and dust transported from adjacent regions contribute to the peaks in fine particle concentration. Indoor air quality is affected by ambient air pollution. Common methods for maintaining good IAQ from harmful outdoor particles are either through the usage of an air purifier (AP) or to install a filter in the heat recovery ventilator (HRV) system. It is important to evaluate the PM10 concentrations in a room using APs and HRVs depending on various system parameters, such as building air-tightness, indoor generation characteristics, and system filter efficiency. The purpose of this study is to compare the performance of AP with that of HRV in reducing PM10 levels in a classroom based on computer simulation. Results show that the filter efficiency of HRV should be increased to over 0.8 under the reference condition in order for the HRV to be compatible with the AP. Increasing the airflow rate of HRV is not an effective way of increasing its filter performance to outperform an AP. We found that HRV performs better as compared to AP in an indoor environment under dusty conditions with the generation rate of over seven times compared to the reference condition.
40
Hany, Nermine, and Hala Alaa. "Thermal comfort optimization through bioclimatic design in Mediterranean cities." F1000Research 10 (June 1, 2022): 1047. http://dx.doi.org/10.12688/f1000research.73017.2.
Full textAbstract:
Background: Bioclimatic design is an approach based on local climate which improves thermal qualities and indoor comfort. Buildings follow this process to minimize negative effects on the environment. However, this approach is still not suitable in developed countries. This study aims to investigate Mediterranean local bioclimatic strategies’ impact on thermal comfort efficiency in housing, by examining architectural elements and treatments. Methods: We adopted a descriptive, analytical, and comparative methodology, complemented with a software simulation, within a qualitative and quantitative approach. Investigation and methodological tools were based on technical information including plans, elevations, photos, and documentation. The approach consisted of multiple stages: a literature review interpreting the concept of bioclimatic design, as well as thermal comfort variables and common Mediterranean building features. Moreover, the paper showcases three examples of successful Mediterranean passive houses. Furthermore, the paper presents a case- studyhouse in Alex West, Alexandria, designed in the Mediterranean Revival style. Results: The results showed that the most influencing building features on thermal comfort were the low-pitched roofs and the top chimney, which achieved 12.6% and 5% improvement in the summer and 13% and 6.8% in winter, respectively. The pergola and porch elements barely had an effect when placed on the northern façade. However, on the southern façade, a positive contribution in the summer by 1.4% and 3.4% respectively were reported, but a slight negative impact in winter by 0.5% and 2% respectively. Conclusions: We examined the impact of common Mediterranean building features , and compared thermal comfort results between case-study houses. Features focusing on passive design for cooling rather than heating, allowing wind flow for maximized natural ventilation, using ventilated pitched roof spaces, using sun shading elements in the proper facades and angles, help passive thermal regulation. The study proposes recommendations for optimizing thermal comfort in residential buildings in Alexandria, Egypt.
41
Hany, Nermine, and Hala Alaa. "Thermal comfort optimization through bioclimatic design in Mediterranean cities." F1000Research 10 (October 15, 2021): 1047. http://dx.doi.org/10.12688/f1000research.73017.1.
Full textAbstract:
Background: Bioclimatic design is an approach based on local climate which improves thermal qualities and indoor comfort. Buildings follow this process to minimize negative effects on the environment. However, this approach is still not suitable in developed countries. This study aims to investigate Mediterranean local bioclimatic strategies’ impact on thermal comfort efficiency in housing, by examining architectural elements and treatments. Methods: We adopted a descriptive, analytical, and comparative methodology, complemented with a software simulation, within a qualitative and quantitative approach. Investigation and methodological tools were based on technical information including plans, elevations, photos, and documentation. The approach consisted of multiple stages: a literature review interpreting the concept of bioclimatic design, as well as thermal comfort variables and common Mediterranean building features. Moreover, the paper showcases three examples of successful Mediterranean passive houses. Furthermore, the paper presents a case- studyhouse in Alex West, Alexandria, designed in the Mediterranean Revival style. Results: The results showed that the most influencing building features on thermal comfort were the low-pitched roofs and the top chimney, which achieved 12.6% and 5% improvement in the summer and 13% and 6.8% in winter, respectively. The pergola and porch elements barely had an effect when placed on the northern façade. However, on the southern façade, a positive contribution in the summer by 1.4% and 3.4% respectively were reported, but a slight negative impact in winter by 0.5% and 2% respectively. Conclusions: We examined the impact of common Mediterranean building features , and compared thermal comfort results between case-study houses. Features focusing on passive design for cooling rather than heating, allowing wind flow for maximized natural ventilation, using ventilated pitched roof spaces, using sun shading elements in the proper facades and angles, help passive thermal regulation. The study proposes recommendations for optimizing thermal comfort in residential buildings in Alexandria, Egypt.
42
Chen, Chun, Bin Zhao, Weilin Cui, Lei Dong, Na An, and Xiangying Ouyang. "The effectiveness of an air cleaner in controlling droplet/aerosol particle dispersion emitted from a patient's mouth in the indoor environment of dental clinics." Journal of The Royal Society Interface 7, no. 48 (December 23, 2009): 1105–18. http://dx.doi.org/10.1098/rsif.2009.0516.
Full textAbstract:
Dental healthcare workers (DHCWs) are at high risk of occupational exposure to droplets and aerosol particles emitted from patients' mouths during treatment. We evaluated the effectiveness of an air cleaner in reducing droplet and aerosol contamination by positioning the device in four different locations in an actual dental clinic. We applied computational fluid dynamics (CFD) methods to solve the governing equations of airflow, energy and dispersion of different-sized airborne droplets/aerosol particles. In a dental clinic, we measured the supply air velocity and temperature of the ventilation system, the airflow rate and the particle removal efficiency of the air cleaner to determine the boundary conditions for the CFD simulations. Our results indicate that use of an air cleaner in a dental clinic may be an effective method for reducing DHCWs' exposure to airborne droplets and aerosol particles. Further, we found that the probability of droplet/aerosol particle removal and the direction of airflow from the cleaner are both important control measures for droplet and aerosol contamination in a dental clinic. Thus, the distance between the air cleaner and droplet/aerosol particle source as well as the relative location of the air cleaner to both the source and the DHCW are important considerations for reducing DHCWs' exposure to droplets/aerosol particles emitted from the patient's mouth during treatments.
43
Mansurov, Rustam Sh, Yuri E. Voskoboinikov, and Vasilisa A. Boeva. "Heat transient processes identification of the elements of internal environment system." Vestnik MGSU, no. 2 (February 2022): 222–31. http://dx.doi.org/10.22227/1997-0935.2022.2.222-231.
Full textAbstract:
Introduction. The study of heat exchange transients in the climate system “Heater-Ventilator-Room”, when ventilator capacity varies step-wise, is presented. The construction of functional relations between inputs and outputs of the system is the object of special attention. This allows for a non-parametric identification of impulse responses in the system for simulation and control.
Materials and methods. The climate system is represented by a combination of several different-type elements with step inputs and experimental data as outputs. Mathematical models of the elements are governed by Volterra integral equation of the 2nd kind. Solution of this equation is an ill-posed problem, and specifics of identification experiments do not allow applying computational methods of classical regularization algorithms. A non-parametric identification of impulse responses for the elements is performed by the authors’ stable algorithm with due regard for real technical systems specifics. The algorithm is founded on stable differentiation by smoothing cubic splines with optimal smoothing parameter estimation and special type boundary conditions.
Results. Non-parametric identification algorithm is adapted for the investigated climate system. The inverse problems of impulse responses identification and the direct problems of heat flux reactions prediction are solved. A high convergence of theoretical and experimental data is shown.
Conclusions. The behavior of the transients is predictable for the climate system under the particular operation mode. The algorithm proposed takes proper account of practical problems specifics. The results obtained suggest the efficiency of the algorithm for applied identification problems solutions in real complex technical systems.
44
Min, Jian Qing, and Zi Bin Xu. "Simulation Study on Indoor Air Ventilation Efficiency Based on Computational Fluid Dynamics." Advanced Materials Research 466-467 (February 2012): 1104–8. http://dx.doi.org/10.4028/www.scientific.net/amr.466-467.1104.
Full textAbstract:
A numerical investigation is presented of the structure of a displacement ventilation convection by using the Reynolds averaged Navier-Stokes equation and K-ε turbulence model. Numerical results are reported for the effect of Gr/Re2 on structure of indoor air convection and ventilation efficiency. The results show that the structure of indoor air convection changes from mechanical ventilation to natural ventilation, and the curves of ventilation efficiency are like “M” with Gr/Re2 increasing.
45
Zhou, Jun, and Xiao Hui Liu. "Design of Natural Ventilation and Analysis of Ventilation Safety in Commercial Building." Applied Mechanics and Materials 539 (July 2014): 55–58. http://dx.doi.org/10.4028/www.scientific.net/amm.539.55.
Full textAbstract:
This paper establishes computer CFD simulation mathematical model of large commercial buildings according to the principle of cubic interpolation function and determines the cubic interpolation function based on triangular elements method. It concludes the cubic polynomial in the process of simulation which improves the efficiency of computer simulation. This paper introduces modeling process and flow diagram of simulation process of numerical simulation of natural ventilation simulation of commercial building. It also simulates the indoor ventilation of building which treats the logistics field model of commercial tower building as the object of study. It concludes two-dimensional and three-dimensional contours of air and humidity. Finally, this paper gets the environmental distribution of the temperature through the simulation calculation and draws temperature change curve with distance which provides technical reference for the design of ventilation safe indoor.
46
Yu, Liang, Zijia Liu, and Yanchun Guo. "Simulation of Indoor Pollutant Distribution in Residential Buildings under Different Ventilation Modes." E3S Web of Conferences 356 (2022): 05046. http://dx.doi.org/10.1051/e3sconf/202235605046.
Full textAbstract:
For clear residential indoor pollutant concentration under different ventilation modes and contaminant distribution, to explore the emission efficiency of different ventilation way, choose suitable way of ventilation, different season in Shenyang, this article selects some typical residence as the research object, interior decoration materials commonly used as indoor pollutant source, based on CFD fluid mechanics principle, Airpak3.0.16 software was used to simulate indoor air flow field and indoor concentration distribution field of formaldehyde, benzene and VOC, and to compare and analyse indoor pollutant distribution law, air age and pollutant discharge efficiency under natural ventilation and mechanical ventilation in winter and summer. The results show that ventilation can effectively discharge most of indoor pollutants. 69% of indoor pollutants can be discharged by natural ventilation in summer, 46% of indoor pollutants can be discharged by natural ventilation in winter, 57% of indoor pollutants can be discharged by mechanical ventilation in summer, and 51% of indoor pollutants can be discharged by mechanical ventilation in winter. Under the condition of the same ventilation volume in the same season, natural ventilation has the best effect in summer, and considering that the energy consumption of mechanical ventilation is much higher than that of natural ventilation, natural ventilation is recommended in summer. The effect of mechanical ventilation is better in winter, and because Shenyang is not suitable to open Windows for ventilation for a long time in winter, mechanical ventilation should be used in winter.
47
Yin, Xin, Xinshan Sun, Minkai Bai, and Zhan Liu. "Numerical simulation of pollutant diffusion in public toilets." E3S Web of Conferences 356 (2022): 05047. http://dx.doi.org/10.1051/e3sconf/202235605047.
Full textAbstract:
Compared with residential restrooms, public toilets usually have higher utilization rates. How to ensure the air quality in the toilets through reasonable ventilation is of great significance to human health. In this study, an office building with a public toilet is selected as the research object, and the Airpak 3.0 software is adopted to simulate the airflow velocity distribution in the toilet with different air change rates and exhaust vent heights. Variations of the air velocity distribution, ammonia concentration, ventilation efficiency, and other parameters, are compared and analyzed. The results show that increasing the air change rate could reduce the concentration of pollutants in the toilet, but it has negative effects on ventilation efficiency. After comprehensive analysis, the desirable air change rate is chosen with the value of 15h-1. The exhaust outlet is set near the source of pollution to facilitate the discharge of pollutants. This work may provide a theoretical basis for amelioration of the toilet ventilation environment.
48
Yang, Young Kwon, Min Young Kim, Yong Woo Song, Sung Ho Choi, and Jin Chul Park. "Windcatcher Louvers to Improve Ventilation Efficiency." Energies 13, no. 17 (August 28, 2020): 4459. http://dx.doi.org/10.3390/en13174459.
Full textAbstract:
Windcatcher louvers are designed to capture air flowing outside a building in order to increase its natural ventilation. There are no studies that have designed the shape of the louver to increase the natural ventilation efficiency of the building. This study aimed to conduct a computational fluid dynamics simulation and mock-up test of a Clark Y airfoil-type windcatcher louver designed to increase the natural ventilation in a building. The following test results were obtained. The optimal angle of attack of the airfoil was calculated via a numerical analysis, which demonstrated that the wind speed was at its highest when the angle of attack was 8°; further, flow separation occurred at angles exceeding 8°, at which point the wind speed began to decrease. The results of the mock-up test demonstrated that the time required to reduce the concentration of fine particles in the indoor air was 120 s shorter when the windcatcher was installed than when it was not, which indicating that the time to reduce particles represents a 37.5%reduction. These results can be seen as reducing the energy consumption of ventilation in the building because the natural ventilation efficiency is increased.
49
Chung, I.-Ping, and Derek Dunn-Rankin. "Using numerical simulation to predict ventilation efficiency in a model room." Energy and Buildings 28, no. 1 (August 1998): 43–50. http://dx.doi.org/10.1016/s0378-7788(97)00061-3.
Full text
50
Wang, Fujen, Indra Permana, Kwowhei Lee, Dibakar Rakshit, and Parisya Premiera Rosulindo. "Improvement of Airflow Distribution and Contamination Control for a Biotech Cleanroom." Atmosphere 13, no. 2 (February 17, 2022): 335. http://dx.doi.org/10.3390/atmos13020335.
Full textAbstract:
The biotech cleanroom industry presents a biological basis for living organisms or their components (bacteria or enzymes) to produce helpful medicine. However, biotech industries such as vaccine production need a clean critical environment and contamination control that is always a vital concern for the manufacturing process. This study investigates a biotech cleanroom through a comprehensive field measurement and numerical simulation. The field measurement test results conformed to the design specification to satisfactorily meet with the cleanroom standard of PIC/S and EU GMP. Furthermore, the field measurement data were used as a basic validation and boundary condition for numerical simulation. The numerical simulation results revealed that the concentration distribution in case 1 as a baseline case showed satisfactory results, with a removal efficiency of 75.2% and ventilation efficiency of 80%. However, there was still a high concentration accumulated in certain areas. The improvement strategy was analyzed through non-unidirectional flow ventilation with different face velocities and by adding one return air grille for case 2 and two return air grilles for case 3. The results revealed that case 2 presented the best results in this study, with a removal efficiency of 86.7% and ventilation efficiency of 82% when supplying air velocity at 0.2 m/s. In addition, increasing the supply air velocity to 0.3 m/s could enhance removal ventilation by around 19% and ventilation efficiency by around 5%.