scholarly journals Analysis and Simulation of Forced Ventilation in Special Condition

2018 ◽  
Vol 168 ◽  
pp. 02003
Author(s):  
Miroslav Rimár ◽  
Andrii Kulikov ◽  
Marcel Fedak ◽  
Milan Abraham
Keyword(s):  
Heat Recovery ◽  
Ventilation System ◽  
Forced Ventilation ◽  
Ansys Fluent ◽  
Closed Area ◽  
Air Ventilation ◽  
Forced Air ◽  
Passive Houses ◽  
Air Circulation ◽  
Made In

The research subject of the current work is heating of the closed area by the forced air ventilation system with heat recovery ventilator and floor radiators. The simulation model was made in ANSYS Fluent 14.0. In the simulation were taken to account the secondary thermal gains from the computers, monitors and humans. The results of the simulation approved that in the modern thermal passive houses heat balance calculations should observe secondary thermal gains from the installed equipment. Also were investigated the air circulation in the closed area and the influence of the different barriers which were installed in the laboratory.

scholarly journals CFD analysis of the ventilation heating system

2019 ◽  
Vol 20 (7) ◽  
pp. 708
Author(s):  
Miroslav Rimár ◽  
Andrii Kulikov ◽  
Marcel Fedak ◽  
Milan Abraham
Keyword(s):  
Heat Balance ◽  
Cfd Simulation ◽  
Heating System ◽  
Cfd Analysis ◽  
Ansys Fluent ◽  
Closed Area ◽  
Building Ventilation ◽  
Passive Houses ◽  
Air Circulation ◽  
The Heat Balance

Air conditioning is a significant part of the contemporary life. A lot of the medical papers confirmed the influence of the thermal comfort to the operability. The aim of the article is to understand the system of the building ventilation with the HRV unit. For this purpose, the CFD simulation model was elaborated. The ANSYS Fluent allows to calculate the heat balance of the room with secondary thermal gains like computers, monitors and humans. The results of the simulation approved that in the modern thermal passive houses heat balance calculations should take into account secondary thermal gains from the installed equipment. Also the air circulation in the closed area and the influence of the different barriers installed in the laboratory were investigated.

DEVELOPMENT OF ADAPTIVE VENTILATION IN MULTIFUNCTIONAL LARGE-SCALE SPACE OF PUBLIC BUILDINGS

2021 ◽  
pp. 19-29
Author(s):  
Виталий Владимирович Шичкин ◽  
Мария Николаевна Жерлыкина ◽  
Сергей Анатольевич Яременко ◽  
Сергей Анатольевич Соловьев
Keyword(s):  
Heat Transfer ◽  
Heat Exchanger ◽  
Large Scale ◽  
Numerical Study ◽  
Ventilation System ◽  
Public Buildings ◽  
Air Conditioners ◽  
Advantages And Disadvantages ◽  
Air Ventilation ◽  
Forced Air

Проанализирована актуальность строительства объектов культурно-массового назначения. Описана целесообразность проектирования многофункциональных трансформируемых помещений для общественных зданий. Приведены достоинства и недостатки применения рециркуляции воздуха как способа энергосбережения. Акцентировано внимание на поддержании чистоты воздуха в помещении и способах борьбы с бактериями и вирусами в приточном воздухе. Предложена схема многозональной общеобменной вентиляции воздуха без рециркуляции с блокированием кондиционеров для взаимозаменяемости с целью обеспечения микроклимата в многофункциональных помещениях общественных зданий. Описана последовательность работы системы вентиляции в теплый и холодный период года. Разработана система рекуперации с промежуточным холодоносителем для теплого периода года. Приведено описание работы установки кондиционирования воздуха. На примере реально существующего объекта выполнено численное исследование режимов работы системы вентиляции с рекуперацией теплоты и холода для трансформируемого помещения. Построен график для определения граничных условий работы рекуператора исходя из соотношения между интенсивностью теплообмена за счёт конвекции и интенсивностью теплообмена за счёт теплопроводности. При различных наружных температурах воздуха и расчетных температурах уходящего воздуха построены графики определения оптимальных параметров температуры воздуха на входе в утилизатор при оптимальных значениях водяного эквивалента . Выявлены и описаны режимы работы кондиционеров с теплоутилизатором в теплый период года, работающих в составе многозональной общеобменной вентиляции воздуха с блокированием кондиционеров для взаимозаменяемости. В ходе численного исследования выявлено, что наибольшая энергоэффективность системы вентиляции с рекуператором будет достигнута при принятии в качестве оптимального значения водяного эквивалента W = 3. We analyzed the relevance of cultural facilities construction. As well, we described the expediency of designing multifunctional transformable spaces for public buildings. Moreover we presented advantages and disadvantages of using air recirculation as a method of energy saving. A special attention is focused on maintaining indoor air clean and on various ways of combatting bacteria and viruses in the intake air. We offered a scheme of multi-zone forced air ventilation without recirculation with blocking air conditioners for interchangeability in order to provide a microclimate in multifunctional spaces of public buildings. We described the sequence of operations in the ventilation system in warm and cold seasons. We also developed a recuperation system with an intermediate refrigerant for warm seasons. The article presents a detailed description of the air conditioning unit operation. We carried out a numerical study of the operating modes of the ventilation system with heat and cold recovery for transformable spaces on the example of a real-existing facility. We show a graph to determine the boundary conditions of the recuperator operation based on the ratio between the intensity of heat transfer due to convection and the intensity of heat transfer due to thermal conductivity. At various outside air temperatures and design temperatures of the outgoing air, we created some graphs for determining the optimal parameters of the air temperature at the inlet to the heat exchanger at the optimal values of the water equivalent. We identified and described several modes of operation of air conditioners with a heat exchanger in warm seasons, operating as part of a multi-zone forced air ventilation with blocking air conditioners for interchangeability. In the course of a numerical study, it was revealed that the highest energy efficiency of a ventilation system with a recuperator could be achieved when the water equivalent value W = 3 is taken as the optimal value.

scholarly journals NUMERICAL RESEARCH OF THE MOISTURE CONDENSATION ELIMINATION IN THE CABIN OF THE UNIFIED TECHNOLOGICAL ELECTRIC TRANSPORT VEHICLE

2018 ◽  
Vol 15 (4) ◽  
pp. 538-546
Author(s):  
N. M. Filkin ◽  
A. M. Tatarkin
Keyword(s):  
Three Dimensional ◽  
Electric Transport ◽  
Three Dimensional Model ◽  
Ansys Fluent ◽  
Air Ventilation ◽  
Fluent Software ◽  
Moisture Condensation ◽  
Transport Vehicle ◽  
Numerical Research ◽  
Forced Air

Introduction. This article deals with the problem of moisture condensation inside the cabin of the technological electric transport vehicle. The hypothesis of using the forced air ventilation in the cabin is substantiated, by which such problem could be solved.Materials and methods. The article describes the application of the ANSYS Fluent Software Package to assess the effect of the location and shape of the ducts on the ventilation process inside the cabin. Accordingly, the key stages of air flow modeling in this program are considered.Results. The main content of the research is to analyze the modeling airflow process in the cabins with a different configuration of inlet and outlet nozzles. Therefore, basing on the analysis of the obtained airflow velocity contours, the conclusion is made about the rational arrangement of the inlet and outlet channels.Discussion and conclusions. The conclusion is made about the necessity of the further research that would refer to creating a three-dimensional model of the cabin. The results of the research as well as resolutions are taken into account.

Transport and trajectory of cough-induced bimodal aerosol in an air-conditioned space

2020 ◽  
pp. 1420326X2094116 ◽  
Author(s):  
Bo Zhang ◽  
Guangyu Guo ◽  
Chao Zhu ◽  
Zhiming Ji ◽  
Chao-Hsin Lin
Keyword(s):  
Ventilation System ◽  
Three Dimensional ◽  
Experimental System ◽  
Ambient Air ◽  
Lagrangian Model ◽  
Breathing Zone ◽  
Cfd Model ◽  
Ansys Fluent ◽  
Liquid Phases ◽  
Air Ventilation

Aerosol generated from a human cough can be a potential major indoor health risk due to the possible transmission of infectious respiratory diseases to surrounding individuals within the same room and even could spread out via air-ventilation/conditioning systems. This study aims to investigate the transport characteristics and trajectory of coughed aerosols under the influence of conditioned air ventilation as well as near-by human breathing zone using computational fluid dynamics (CFD). An experimental system consisting of air-conditioned space with multiple inlets and outlets, a cough simulator and a receiver was built to validate the CFD predictions. The comparison is in good agreement. The CFD model was established as a transient three-dimensional multiphase multicomponent Eulerian–Lagrangian model and numerically solved using commercial software ANSYS Fluent. Both gas and liquid phases were modelled as multicomponent mixtures. With this CFD model, the indoor transport and trajectory of coughed aerosols can be accounted for the distributions of portions inhaled by each manikin, deposited on surfaces of manikins and chamber walls, as well as recirculated back into the ventilation system. Results reveal that the aerosol source location and the ambient air movement can be crucial factors of aerosol trajectory in terms of direct and indirect influence.

scholarly journals CFD Analysis and Electrical Efficiency Improvement of a Hybrid PV/T Panel Cooled by Forced Air Circulation

2021 ◽  
Vol 12 (6) ◽  
pp. 1152-1169
Author(s):  
Alok Kumar Singh, Et. al.
Keyword(s):  
Renewable Energy Sources ◽  
Thermal Contact ◽  
Energy Sources ◽  
Total Efficiency ◽  
Pv System ◽  
Total Heat Transfer ◽  
Ansys Fluent ◽  
Fan Speed ◽  
Forced Air ◽  
Air Circulation

Renewable energy sources are becoming more and more popular, regarding the pollution and non-sustainability of common energy sources. The study mainly focused on the improvement of the PV collector performance by using ANSYS fluent.  The design of the fin will change according to the previous study. In the current study, we will increase the thermal contact area of the fin by changing the design of the fin. The change in the design of the fin will increase the total heat transfer and efficiency of the system. It concluded that with better-designed fin arrangements, the required fan speed could be lowered for any number of fins or similar results could be obtained with fewer fins. On the other hand, since the power required by the PV-powered fan will also decrease with fewer fins and at lower air velocities, the total efficiency obtained from the PV system will also increase.

scholarly journals CFD Analysis and Electrical Efficiency Improvement of a Hybrid PV/T Panel Cooled by Forced Air Circulation

2018 ◽  
Vol 2018 ◽  
pp. 1-11 ◽  
Author(s):  
Gökhan Ömeroğlu
Keyword(s):  
Heat Transfer ◽  
Heat Removal ◽  
Critical Threshold ◽  
Cfd Analysis ◽  
Ansys Fluent ◽  
Electrical Efficiency ◽  
Computational Fluid Dynamics Cfd ◽  
Forced Air ◽  
Air Circulation

The thermal and electrical efficiency of a custom-designed PV/T panel cooled by forced air circulation was investigated by experimental and computational fluid dynamics (CFD) analysis. Experiments were carried out with four different array configurations, under constant irradiation of 1100 W/m2 and 3 different air velocities (3.3 m/s, 3.9 m/s, and 4.5 m/s). The heat transfer surface area and forced air circulation are known to positively affect the total heat transfer, and therefore, it is foreseeable that an increased number of fins and higher air velocities will help maintain the electrical efficiency of the panel at higher levels. The main objective of this study is to determine the critical threshold for the abovementioned parameters as well as to show how important parameters, such as fin arrangement and consequent turbulent air flows, are for satisfying the heat removal needs. Highest efficiency was achieved with a 108 pc type 1 arrangement at 12.02% as expected. Nevertheless, while the 108 pc type 2 arrangement could maintain the electrical efficiency at 11.81%, a close level of 11.55% could be obtained with a 54 pc type 2 arrangement. Experimental results are compared with ANSYS Fluent program, and the effect of the number and arrangement of the fins on the efficiency of the panel has been shown.

scholarly journals Air circulation in a gastrointestinal light source box and endoscope in the era of SARS-CoV-2 and airborne transmission of microorganisms

2021 ◽  
Vol 09 (03) ◽  
pp. E482-E486
Author(s):  
Stanislas Chaussade ◽  
Einas Abou Ali ◽  
Rachel Hallit ◽  
Arthur Belle ◽  
Maximilien Barret ◽  
...  
Keyword(s):  
Light Source ◽  
Cooling System ◽  
Air Cooling ◽  
Airborne Transmission ◽  
Plastic Tube ◽  
Care Workers ◽  
Air Cooling System ◽  
Forced Air ◽  
Air Circulation ◽  
Closed Environment

Abstract Background and study aims The role that air circulation through a gastrointestinal endoscopy system plays in airborne transmission of microorganisms has never been investigated. The aim of this study was to explore the potential risk of transmission and potential improvements in the system. Methods We investigated and described air circulation into gastrointestinal endoscopes from Fujifilm, Olympus, and Pentax. Results The light source box contains a lamp, either Xenon or LED. The temperature of the light is high and is regulated by a forced-air cooling system to maintain a stable temperature in the middle of the box. The air used by the forced-air cooling system is sucked from the closed environment of the patient through an aeration port, located close to the light source and evacuated out of the box by one or two ventilators. No filter exists to avoid dispersion of particles outside the processor box. The light source box also contains an insufflation air pump. The air is sucked from the light source box through one or two holes in the air pump and pushed from the air pump into the air pipe of the endoscope through a plastic tube. Because the air pump does not have a dedicated HEPA filter, transmission of microorganisms cannot be excluded. Conclusions Changes are necessary to prevent airborne transmission. Exclusive use of an external CO2 pump and wrapping the endoscope platform with a plastic film will limit scatter of microorganisms. In the era of pandemic virus with airborne transmission, improvements in gastrointestinal ventilation systems are necessary to avoid contamination of patients and health care workers.

scholarly journals Effect of Mechanical Ventilation on Accidental Hydrogen Releases—Large-Scale Experiments

Energies ◽  
2021 ◽  
Vol 14 (11) ◽  
pp. 3008
Author(s):  
Agnieszka W. Lach ◽  
André V. Gaathaug
Keyword(s):  
Mechanical Ventilation ◽  
Mass Flow ◽  
Large Scale ◽  
Ventilation System ◽  
Hydrogen Gas ◽  
Forced Ventilation ◽  
British Standard ◽  
Confined Spaces ◽  
Series Of Experiments ◽  
Rate Limit

This paper presents a series of experiments on the effectiveness of existing mechanical ventilation systems during accidental hydrogen releases in confined spaces, such as underground garages. The purpose was to find the mass flow rate limit, hence the TPRD diameter limit, that will not require a change in the ventilation system. The experiments were performed in a 40 ft ISO container in Norway, and hydrogen gas was used in all experiments. The forced ventilation system was installed with a standard 315 mm diameter outlet. The ventilation parameters during the investigation were British Standard with 10 ACH and British Standard with 6 ACH. The hydrogen releases were obtained through 0.5 mm and 1 mm nozzles from different hydrogen reservoir pressures. Both types of mass flow, constant and blowdown, were included in the experimental matrix. The analysis of the hydrogen concentration of the created hydrogen cloud in the container shows the influence of the forced ventilation on hydrogen releases, together with TPRD diameter and reservoir pressure. The generated experimental data will be used to validate a CFD model in the next step.

scholarly journals Verification of the effect of sleeping environment and humidification on middle-aged people in whole-house air-conditioning ventilation system housing

2019 ◽  
Vol 111 ◽  
pp. 02044
Author(s):  
Akemi Iwaki ◽  
Takashi Akimoto ◽  
Naho Misumi ◽  
Takuya Furuhashi
Keyword(s):  
Blood Pressure ◽  
Moisture Content ◽  
Air Conditioning ◽  
Sleep Latency ◽  
Ventilation System ◽  
Circulation Type ◽  
Living Environment ◽  
Aged People ◽  
Air Circulation ◽  
Skin Moisture

This study focused on the thermal comfort of air circulation-type whole-house air-conditioning ventilation systems. We studied the influence of 24-h continuous whole-house air-conditioning on the living environment in which the occupant is sleeping. A survey was conducted in the summer of 2016 and winter of 2017 to ascertain the influence on the sleeping environment, skin moisture content, and blood pressure. We then compared the results with those of the sleeping environment of residents in air-conditioned housing surveyed the previous year. The sleeping environment when using a personal humidifier around the occupant’s head was examined during winter when the humidity is low. The results indicated that sleep latency was significantly shortened in the 24-h continuous whole-house air-conditioning ventilation system in both summer and winter because the temperature control of the bedroom before going to bed affects the sleep latency. Subjectively, no participants felt dryer than the values measured in the bedroom environment. The results implied that the comfort of the entire building was improved with continuous air-conditioned housing.

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