Search results for: Mechanical ventilation and Prone position.

Authors: Maha Salah Abdullah Ismail, Mahmoud M. Alsagheir, Mohammed Salah Abd Allah

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Acute respiratory distress syndrome (ARDS) is characterized by permeability pulmonary edema and refractory hypoxemia. Lung-protective ventilation is still the key of better outcome in ARDS. Prone position reduces the trans-pulmonary pressure gradient, recruiting collapsed regions of the lung without increasing airway pressure or hyperinflation. Prone ventilation showed improved oxygenation and improved outcomes in severe hypoxemic patients with ARDS. This study evaluates the effect of prone positioning on mechanically ventilated patients with ARDS. A quasi-experimental design was carried out at Critical Care Units, on 60 patients. Two tools were utilized to collect data; Socio demographic, medical and clinical outcomes data sheet. Results of the present study indicated that prone position improves oxygenation in patients with severe respiratory distress syndrome. The study recommended that use prone position in patients with severe ARDS, as early as possible and for long sessions. Also, replication of this study on larger probability sample at the different geographical location is highly recommended.

Keywords: Acute respiratory distress syndrome, Critical care, Mechanical ventilation and Prone position.

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Authors: Bin Su

Abstract:

According to the Auckland climate, building passive design more focus on improving winter indoor thermal and health conditions. Based on field study data of indoor air temperature and relative humidity close to ceiling and floor of an insulated Auckland townhouse with and without a whole home mechanical ventilation system, this study is to analysis variation of indoor microclimate data of an Auckland townhouse using or not using the mechanical ventilation system to evaluate winter indoor thermal and health conditions for the future house design with a mechanical ventilation system.

Keywords: House ventilation, indoor thermal condition, indoor health condition, passive design.

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Authors: Ayşin Sev, Görkem Aslan

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Sustainable tall buildings that provide comfortable, healthy and efficient indoor environments are clearly desirable as the densification of living and working space for the world’s increasing population proceeds. For environmental concerns, these buildings must also be energy efficient. One component of these tasks is the provision of indoor air quality and thermal comfort, which can be enhanced with natural ventilation by the supply of fresh air. Working spaces can only be naturally ventilated with connections to the outdoors utilizing operable windows, double facades, ventilation stacks, balconies, patios, terraces and skygardens. Large amounts of fresh air can be provided to the indoor spaces without mechanical air-conditioning systems, which are widely employed in contemporary tall buildings. This paper tends to present the concept of natural ventilation for sustainable tall office buildings in order to achieve healthy and comfortable working spaces, as well as energy efficient environments. Initially the historical evolution of ventilation strategies for tall buildings is presented, beginning with natural ventilation and continuing with the introduction of mechanical airconditioning systems. Then the emergence of natural ventilation due to the health and environmental concerns in tall buildings is handled, and the strategies for implementing this strategy are revealed. In the next section, a number of case studies that utilize this strategy are investigated. Finally, how tall office buildings can benefit from this strategy is discussed.

Keywords: Tall office building, natural ventilation, energy efficiency, double-skin façade, stack ventilation, air conditioning.

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Authors: C. Lanzerstorfer

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The off-gas from the basic oxygen furnace (BOF), where pig iron is converted into steel, is treated in the primary ventilation system. This system is in full operation only during oxygen-blowing when the BOF converter vessel is in a vertical position. When pig iron and scrap are charged into the BOF and when slag or steel are tapped, the vessel is tilted. The generated emissions during charging and tapping cannot be captured by the primary off-gas system. To capture these emissions, a secondary ventilation system is usually installed. The emissions are captured by a canopy hood installed just above the converter mouth in tilted position. The aim of this study was to investigate the dependence of Zn and other components on the particle size of BOF secondary ventilation dust. Because of the high temperature of the BOF process it can be expected that Zn will be enriched in the fine dust fractions. If Zn is enriched in the fine fractions, classification could be applied to split the dust into two size fractions with a different content of Zn. For this air classification experiments with dust from the secondary ventilation system of a BOF were performed. The results show that Zn and Pb are highly enriched in the finest dust fraction. For Cd, Cu and Sb the enrichment is less. In contrast, the non-volatile metals Al, Fe, Mn and Ti were depleted in the fine fractions. Thus, air classification could be considered for the treatment of dust from secondary BOF off-gas cleaning.

Keywords: Air classification, converter dust, recycling, zinc.

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Authors: Minjeong Kim, Seungchul Lee, Iman Janghorban Esfahani, Jeong Tai Kim, Chang Kyoo Yoo

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This study was carried out for an underground subway station at Seoul Metro, Korea. The optimal set-points of the ventilation control system are determined every 3 hours, then, the ventilation controller adjusts the ventilation fan speed according to the optimal set-point changes. Compared to manual ventilation system which is operated irrespective of the OAQ, the IDP-based ventilation control system saves 3.7% of the energy consumption. Compared to the fixed set-point controller which is operated irrespective of the IAQ diurnal variation, the IDP-based controller shows better performance with a 2% decrease in energy consumption, maintaining the comfortable IAQ range inside the station.

Keywords: Indoor air quality, iterative dynamic algorithm, outdoor air information, ventilation control system.

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Authors: An-Shik Yang, Chiang-Ho Cheng, Jen-Hao Wu, Yu-Hsuan Juan

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Natural ventilation has played an important role for many low energy-building designs. It has been also noticed as a essential subject to persistently bring the fresh cool air from the outside into a building. This study carried out the computational fluid dynamics (CFD)-based simulations to examine the natural ventilation development of a work area in a public building. The simulated results can be useful to better understand the indoor microclimate and the interaction of wind with buildings. Besides, this CFD simulation procedure can serve as an effective analysis tool to characterize the airing performance, and thereby optimize the building ventilation for strengthening the architects, planners and other decision makers on improving the natural ventilation design of public buildings.

Keywords: CFD simulations, Natural ventilation, Microclimate, Wind environment.

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Authors: Andres Gonzalez, Adam Boies, Jacob Swanson, David Kittelson

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The concern of the indoor air quality (IAQ) has been increasing due to its risk to human health. The smoking, sweeping, and stove and stovetop use are the activities that have a major contribution to the indoor air pollution. Outdoor air pollution also affects IAQ. The most important factors over IAQ from cooking activities are the materials, fuels, foods, and ventilation. The low-cost, mobile air quality monitoring (LCMAQM) sensors, is reachable technology to assess the IAQ. This is because of the lower cost of LCMAQM compared to conventional instruments. The IAQ was assessed, using LCMAQM, during cooking activities in a University of Minnesota graduate-housing evaluating different ventilation systems. The gases measured are carbon monoxide (CO) and carbon dioxide (CO₂). The particles measured are particle matter (PM) _2.5 micrometer (µm) and lung deposited surface area (LDSA). The measurements are being conducted during April 2019 in Como Student Community Cooperative (CSCC) that is a graduate housing at the University of Minnesota. The measurements are conducted using an electric stove for cooking. The amount and type of food and oil using for cooking are the same for each measurement. There are six measurements: two experiments measure air quality without any ventilation, two using an extractor as mechanical ventilation, and two using the extractor and windows open as mechanical and natural ventilation. 3The results of experiments show that natural ventilation is most efficient system to control particles and CO₂. The natural ventilation reduces the concentration in 79% for LDSA and 55% for PM_2.5, compared to the no ventilation. In the same way, CO₂ reduces its concentration in 35%. A well-mixed vessel model was implemented to assess particle the formation and decay rates. Removal rates by the extractor were significantly higher for LDSA, which is dominated by smaller particles, than for PM_2.5, but in both cases much lower compared to the natural ventilation. There was significant day to day variation in particle concentrations under nominally identical conditions. This may be related to the fat content of the food. Further research is needed to assess the impact of the fat in food on particle generations.

Keywords: Cooking, indoor air quality, low-cost sensor, ventilation.

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Authors: Bin Su

Abstract:

Auckland has a temperate climate with comfortable warm, dry summers and mild, wet winters. Auckland house design not only focus on winter thermal performance and indoor thermal condition, but also indoor moisture control, which is closely related to indirect health effects such as dust mites, fungi, etc. Most Auckland houses are designed to use temporary heating for winter indoor thermal comfort. Based on field study data of indoor microclimate conditions of two Auckland townhouses with a whole home mechanical ventilation system or a passive wind directional skylight vent, this study is to evaluate and compare indoor moisture conditions of two insulated townhouses only using temporary heating with different ventilation systems.

Keywords: House ventilation, house thermal design, indoor health condition, indoor moisture control.

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Authors: Zahra Ghiabaklou

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Ventilation is a fundamental requirement for occupant health and indoor air quality in buildings. Natural ventilation can be used as a design strategy in free-running buildings to: • Renew indoor air with fresh outside air and lower room temperatures at times when the outdoor air is cooler. • Promote air flow to cool down the building structure (structural cooling). • Promote occupant physiological cooling processes (comfort cooling). This paper focuses on ways in which ventilation can provide the mechanism for heat dissipation and cooling of the building structure..It also discusses use of ventilation as a means of increasing air movement to improve comfort when indoor air temperatures are too high. The main influencing factors and design considerations and quantitative guidelines to help meet the design objectives are also discussed.

Keywords: Natural Ventilation, Sustainable Building, Passive Cooling, Energy Saving

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Authors: Ramy H. Mohammed

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Displacement ventilation of a room with an occupant is modeled using CFD. The geometry of manikin is accurately represented in CFD model to minimize potential. Indoor zero equation turbulence model is used to simulate all cases and the effect of the thermal radiation from manikin is taken into account. After validation of the code, predicted mean vote, mean age of air, and ventilation effectiveness are used to predict the thermal comfort zones and indoor air quality. The effect of the inlet velocity and temperature on the thermal comfort and indoor air quality is investigated. The results show that the inlet velocity has great effect on the thermal comfort and indoor air quality and low inlet velocity is sufficient to establish comfortable conditions inside the room. In addition, the displacement ventilation system achieves not only thermal comfort in ventilated rooms, but also energy saving of fan power.

Keywords: Displacement ventilation, Energy saving, Thermal comfort, Turbulence model.

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Authors: Azian Hariri, M. Z. M Yusof, A. M. Leman

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Experimental study was conducted to assess personal welding fumes exposure toward welders during an aluminum metal inert gas (MIG) process. The welding process was carried out by a welding machine attached to a Computer Numerical Control (CNC) workbench. A dummy welder was used to replicate welder during welding works and was attached with sampling pumps and filter cassettes for welding fumes sampling. Direct reading instruments to measure air velocity, humidity, temperature and particulate matter with diameter size 10µm or less (PM₁₀) were located behind the dummy welder and parallel to the neck collar level to make sure the measured welding fumes exposure were not being influenced by other factors. Welding fumes exposure during standing and sitting position with and without the usage of local exhaust ventilation (LEV) was investigated. Welding fume samples were then digested and analyzed by using inductively coupled plasma mass spectroscopy (ICP-MS) according to ASTM D7439-08 method. The results of the study showed the welding fume exposure during sitting was lower compared to standing position. LEV helped reduce aluminum and lead exposure to acceptable levels during standing position. However during sitting position reduction of exposure was smaller. It can be concluded that welder position and the correct positioning of LEV should be implemented for effective exposure reduction. 

Keywords: ICP-MS, MIG process, personal sampling, welding fumes exposure.

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Authors: Kyung Jin Ryu, MakhsudaJuraeva, Sang-Hyun Jeongand Dong Joo Song

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Clean air in subway station is important to passengers. The Platform Screen Doors (PSDs) can improve indoor air quality in the subway station; however the air quality in the subway tunnel is degraded. The subway tunnel has high CO2 concentration and indoor particulate matter (PM) value. The Indoor Air Quality (IAQ) level in subway environment degrades by increasing the frequency of the train operation and the number of the train. The ventilation systems of the subway tunnel need improvements to have better air-quality. Numerical analyses might be effective tools to analyze the performance of subway twin-track tunnel ventilation systems. An existing subway twin-track tunnel in the metropolitan Seoul subway system is chosen for the numerical simulations. The ANSYS CFX software is used for unsteady computations of the airflow inside the twin-track tunnel when the train moves. The airflow inside the tunnel is simulated when one train runs and two trains run at the same time in the tunnel. The piston-effect inside the tunnel is analyzed when all shafts function as the natural ventilation shaft. The supplied air through the shafts is mixed with the pollutant air in the tunnel. The pollutant air is exhausted by the mechanical ventilation shafts. The supplied and discharged airs are balanced when only one train runs in the twin-track tunnel. The pollutant air in the tunnel is high when two trains run simultaneously in opposite direction and all shafts functioned as the natural shaft cases when there are no electrical power supplies in the shafts. The remained pollutant air inside the tunnel enters into the station platform when the doors are opened.

Keywords: indoor air quality, subway twin-track tunnel, train-induced wind

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Authors: Ramy H. Mohammed

Abstract:

Understanding the behavior of airflow in a room is essential for building designers to provide the most efficient design of ventilation system, and having acceptable indoor air quality. This trend is the motive to solve the relationship between airflow parameters and thermal comfort. This paper investigates airflow characteristics, indoor air quality (IAQ), and the thermal comfort (TC) in a ventilated room with a displacement ventilation system using three dimensional CFD code [AirPak 2.0.6]. After validation of the code, a numerical study is executed for a typical room with dimensions of 5m by 3m by 3m height according to a variety of supply air velocities, supply air temperature and supply air relative humidity. The finite volume method and the indoor zero equation turbulence models are employed for solving the governing equations numerically. The temperature field and the mean age of air (MAA) in the modeled room for a displacement ventilation system are determined according to a variety of the above parameters. The variable air volume (VAV) systems with different supply air velocity are applicable to control room air temperature for a displacement ventilation system.

Keywords: Displacement ventilation, AirPak, Indoor zero equation, MAA.

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Authors: Su Ying-Ming

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High density of high rise buildings in urban areas lead to a deteriorative Urban Heat Island Effect, gradually. This study focuses on discussing the relationship between urban layout and ventilation comfort in street canyons. This study takes Songjiang Nanjing Rd. area of Taipei, Taiwan as an example to evaluate the wind environment comfort index by field measurement and Computational Fluid Dynamics (CFD) to improve both the quality and quantity of the environment. In this study, different factors including street blocks size, the width of buildings, street width ratio and the direction of the wind were used to discuss the potential of ventilation. The environmental wind field was measured by the environmental testing equipment, Testo 480. Evaluation of blocks sizes, the width of buildings, street width ratio and the direction of the wind was made under the condition of constant floor area with the help of Stimulation CFD to adjust research methods for optimizing regional wind environment. The results of this study showed the width of buildings influences the efficiency of outdoor ventilation; improvement of the efficiency of ventilation with large street width was also shown. The study found that Block width and H/D value and PR value has a close relationship. Furthermore, this study showed a significant relationship between the alteration of street block geometry and outdoor comfortableness.

Keywords: Urban ventilation path, ventilation efficiency indices, CFD, building layout.

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Authors: Karina Natali, Wei-Hwa Chiang

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This study examines the stack ventilation performance of an office building located in Taipei, Taiwan. Atriums in this building act as stacks that facilitate buoyancy-driven ventilation. Computational Fluid Dynamic (CFD) simulations are used to identify interior airflow patterns, and then used these patterns to assess the building’s heat expulsion efficiency. Ambient temperatures of 20°C were adopted as the typical seasonal spring temperature range in Taipei. Further, “zero-wind” conditions are established to ensure simulation results reflected only the buoyancy effect. After checking results against neutral pressure level (NPL) level, airflow, air velocity, and indoor temperature stratification, the lower stack is modified to reduce the NPL in order to remove heat accumulated on the top floor.

Keywords: Natural ventilation, side outlet, stack effect, thermal comfort.

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Authors: Ying-Chang Yu, Yuan-Lung Lo

Abstract:

Building ventilation performance is an important indicator of indoor comfort. However, in addition to the geometry of the building or the proportion of the opening, the ventilation performance is also very much related to the actual wind pressure of the building. There are more and more contemporary building designs built with multi-layer exterior envelope. Due to ventilation and view observatory requirement, the porous outer layer of the building is commonly adopted and has a significant wind damping effect, causing the phenomenon of actual wind pressure loss. However, the relationship between the wind damping effect and the actual wind pressure is not linear. This effect can make the indoor ventilation of the building rationalized to reasonable range under the condition of high wind pressure, and also maintain a good amount of ventilation performance under the condition of low wind pressure. In this study, wind tunnel experiments were carried out to simulate the different wind pressures flow through the porous outer layer, and observe the actual wind pressure strength engage with the window layer to find the decreasing relationship between the damping effect of the porous shell and the wind pressure. Experiment specimen scale was designed to be 1:50 for testing real-world building conditions; the study found that the porous enclosure has protective shielding without affecting low-pressure ventilation. Current study observed the porous skin may damp more wind energy to ease the wind pressure under high-speed wind. Differential wind speed may drop the pressure into similar pressure level by using porous skin. The actual mechanism and value of this phenomenon will need further study in the future.

Keywords: Renault number, porous media, wind damping, wind tunnel test, building ventilation.

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Authors: Sepideh Samadzadehyazdi, Mohammad Javad Khalili, Sarvenaz Samadzadehyazdi, Mohammad Javad Mahdavinejad

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The term ‘Windphil Architecture’ refers to the building that facilitates natural ventilation by architectural elements. Natural ventilation uses the natural forces of wind pressure and stacks effect to direct the movement of air through buildings. Natural ventilation is increasingly being used in contemporary buildings to minimize the consumption of non-renewable energy and it is an effective way to improve indoor air quality. The main objective of this paper is to identify the strategies of using natural ventilation in Iranian modern buildings. In this regard, the research method is ‘descriptive-analytical’ that is based on comparative techniques. To simulate wind flow in the interior spaces of case studies, FLUENT software has been used. Research achievements show that it is possible to use natural ventilation to create a thermally comfortable indoor environment. The natural ventilation strategies could be classified into two groups of environmental characteristics such as public space structure, and architectural characteristics including building form and orientation, openings, central courtyards, wind catchers, roof, wall wings, semi-open spaces and the heat capacity of materials. Having investigated modern buildings of Iran, innovative elements like wind catchers and wall wings are less used than the traditional architecture. Instead, passive ventilation strategies have been more considered in the building design as for the roof structure and openings.

Keywords: Natural ventilation strategies, wind catchers, wind flow, Iranian modern buildings.

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Authors: Daniel Micallef, Damien Bounaudet, Robert N. Farrugia, Simon P. Borg, Vincent Buhagiar, Tonio Sant

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The physical effects of upstream flow obstructions such as vegetation on cross-ventilation phenomena of a building are important for issues such as indoor thermal comfort. Modelling such effects in Computational Fluid Dynamics simulations may also be challenging. The aim of this work is to establish the cross-ventilation jet behaviour in such complex terrain conditions as well as to provide guidelines on the implementation of CFD numerical simulations in order to model complex terrain features such as vegetation in an efficient manner. The methodology consists of onsite measurements on a test cell coupled with numerical simulations. It was found that the cross-ventilation flow is highly turbulent despite the very low velocities encountered internally within the test cells. While no direct measurement of the jet direction was made, the measurements indicate that flow tends to be reversed from the leeward to the windward side. Modelling such a phenomenon proves challenging and is strongly influenced by how vegetation is modelled. A solid vegetation tends to predict better the direction and magnitude of the flow than a porous vegetation approach. A simplified terrain model was also shown to provide good comparisons with observation. The findings have important implications on the study of cross-ventilation in complex terrain conditions since the flow direction does not remain trivial, as with the traditional isolated building case.

Keywords: Complex terrain, cross-ventilation, wind driven ventilation, Computational Fluid Dynamics (CFD), wind resource.

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Authors: Wei-Hwa Chiang, Hao-Hsiang Hsu, Jian-Sheng Huang

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Appropriate ventilation in a classroom is helpful for enhancing air exchange rate and student concentration. This study focuses on the effects of fenestration in a four-story school building by performing numerical simulation of a building when considering indoor and outdoor environments simultaneously. The wind profile function embedded in PHOENICS code was set as the inlet boundary condition in a suburban environment. Sixteen fenestration combinations were compared in a classroom containing thirty seats. This study evaluates mean age of air (AGE) and airflow pattern of a classroom on different floors. Considering both wind profile and fenestration effects, the airflow on higher floors is channeled toward the area near ceiling in a room and causes older mean age of air in the breathing zone. The results in this study serve as a useful guide for enhancing natural ventilation in a typical school building.

Keywords: Cross ventilation, Fenestration effect, Wind profile, Mean age of air, CFD

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Authors: Himanshu Dehra

Abstract:

An experimental study was conducted for ascertaining electrical and thermal characteristics of a pair of photovoltaic (PV) modules integrated with solar wall of an outdoor room. A pre-fabricated outdoor room was setup for conducting outdoor experiments on a PV solar wall with passive and active ventilation through the outdoor room. The selective operating conditions for glass coated PV modules were utilized for establishing their electrical and thermal characteristics. The PV solar wall was made up of glass coated PV modules, a ventilated air column, and an insulating layer of polystyrene filled plywood board. The measurements collected were currents, voltages, electric power, air velocities, temperatures, solar intensities, and thermal time constant. The results have demonstrated that: i) a PV solar wall installed on a wooden frame was of more heat generating capacity in comparison to a window glass or a standalone PV module; ii) generation of electric power was affected with operation of vertical PV solar wall; iii) electrical and thermal characteristics were not significantly affected by heat and thermal storage losses; and iv) combined heat and electricity generation were function of volume of thermal and electrical resistances developed across PV solar wall. Finally, a comparison of temperature plots of passive and active ventilation envisaged that fan pressure was necessary to avoid overheating of the PV solar wall. The active ventilation was necessary to avoid over-heating of the PV solar wall and to maintain adequate ventilation of room under mild climate conditions.

Keywords: Photovoltaic solar wall, solar energy, passive ventilation, active ventilation.

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Authors: C. Nutphuang, S. Chirarattananon, V.D. Hien

Abstract:

In research on natural ventilation, and passive cooling with forced convection, is essential to know how heat flows in a solid object and the pattern of temperature distribution on their surfaces, and eventually how air flows through and convects heat from the surfaces of steel under roof. This paper presents some results from running the computational fluid dynamic program (CFD) by comparison between natural ventilation and forced convection within roof attic that is received directly from solar radiation. The CFD program for modeling air flow inside roof attic has been modified to allow as two cases. First case, the analysis under natural ventilation, is closed area in roof attic and second case, the analysis under forced convection, is opened area in roof attic. These extend of all cases to available predictions of variations such as temperature, pressure, and mass flow rate distributions in each case within roof attic. The comparison shows that this CFD program is an effective model for predicting air flow of temperature and heat transfer coefficient distribution within roof attic. The result shows that forced convection can help to reduce heat transfer through roof attic and an around area of steel core has temperature inner zone lower than natural ventilation type. The different temperature on the steel core of roof attic of two cases was 10-15 oK.

Keywords: CFD program, natural ventilation, forcedconvection, heat transfer, air flow.

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Authors: Amon Tunwannarux, Supanunt Tunwannarux

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This paper describes the design concepts and implementation of a 5-Joint mechanical arm for a rescue robot named CEO Mission II. The multi-joint arm is a five degree of freedom mechanical arm with a four bar linkage, which can be stretched to 125 cm. long. It is controlled by a teleoperator via the user-friendly control and monitoring GUI program. With Inverse Kinematics principle, we developed the method to control the servo angles of all arm joints to get the desired tip position. By clicking the determined tip position or dragging the tip of the mechanical arm on the computer screen to the desired target point, the robot will compute and move its multi-joint arm to the pose as seen on the GUI screen. The angles of each joint are calculated and sent to all joint servos simultaneously in order to move the mechanical arm to the desired pose at once. The operator can also use a joystick to control the movement of this mechanical arm and the locomotion of the robot. Many sensors are installed at the tip of this mechanical arm for surveillance from the high level and getting the vital signs of victims easier and faster in the urban search and rescue tasks. It works very effectively and easy to control. This mechanical arm and its software were developed as a part of the CEO Mission II Rescue Robot that won the First Runner Up award and the Best Technique award from the Thailand Rescue Robot Championship 2006. It is a low cost, simple, but functioning 5-Jiont mechanical arm which is built from scratch, and controlled via wireless LAN 802.11b/g. This 5-Jiont mechanical arm hardware concept and its software can also be used as the basic mechatronics to many real applications.

Keywords: Multi-joint, mechanical arm, inverse kinematics, rescue robot, GUI control program.

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Authors: D. Aubin, D. Won, H. Schleibinger, P. Lajoie, D. Gauvin, J.-M. Leclerc

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This paper describes the results obtained in a two-year randomized intervention field study investigating the impact of ventilation rates on indoor air quality (IAQ) and the respiratory health of asthmatic children in Québec City, Canada. The focus of this article is on the comparative effectiveness of heat recovery ventilators (HRVs) and energy recovery ventilators (ERVs) at increasing ventilation rates, improving IAQ, and maintaining an acceptable indoor relative humidity (RH). In 14% of the homes, the RH was found to be too low in winter. Providing more cold and dry outside air to under-ventilated homes in winter further reduces indoor RH. Thus, low-RH homes in the intervention group were chosen to receive ERVs (instead of HRVs) to increase the ventilation rate. The installation of HRVs or ERVs led to a near doubling of the ventilation rates in the intervention group homes which led to a significant reduction in the concentration of several key of pollutants. The ERVs were also effective in maintaining an acceptable indoor RH since they avoided excessive dehumidification of the home by recovering moisture from the exhaust airstream through the enthalpy core, otherwise associated with increased cold supply air rates.

Keywords: Asthma, field study, indoor air quality, ventilation.

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Authors: Hankun Lin, Yiqiang Xiao, Qiaosheng Zhan

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Shading devices (SDs) are widely used in buildings in the hot-humid climate areas for reducing cooling energy consumption for interior temperature, as the result of reducing the solar radiation directly. Contrasting the surface temperature of materials of SDs to the glass on the building façade could give more analysis for the shading effect. On the other side, SDs are much more used as the independence system on building façade in hot-humid area. This typical construction could have some impacts on building ventilation as well. This paper discusses the outdoor SDs’ effects on the building thermal environment and ventilation, through a set of measurements on a 2-floors office building in Guangzhou, China, which install a dynamic aluminum SD-system around the façade on 2^nd-floor. The measurements recorded the in/outdoor temperature, relative humidity, velocity, and the surface temperature of the aluminum panel and the glaze. After that, a CFD simulation was conducted for deeper discussion of ventilation. In conclusion, this paper reveals the temperature differences on the different material of the façade, and finds that the velocity of indoor environment could be reduced by the outdoor SDs.

Keywords: Outdoor shading devices, hot-humid area, temperature, ventilation, measurement, CFD.

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Authors: Marketa Kotova, Jana Kolarova, Ludek Zalud, Petr Dobsak

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A game for training of breath (TRABR) for continuous monitoring of pulmonary ventilation during the patients’ therapy focuses especially on monitoring of their ventilation processes. It is necessary to detect, monitor and differentiate abdominal and thoracic breathing during the therapy. It is a fun form of rehabilitation where the patient plays and also practicing isolated breathing. Finally the game to practice breath was designed to evaluate whether the patient uses two types of breathing or not.

Keywords: Pulmonary ventilation, thoracic breathing, abdominal breathing, breath monitoring using pressure sensors, game TRABR (TRAining of BReath).

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Authors: Dong-Mei Pan, Liang XIA, Ming-Yin Chan

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This paper reports an experimental study on a sleeping thermal manikin in a room equipped with a mixing ventilation system. In the experimental work, heat loss from the sleeping thermal manikin was measured under different conditions. The supply air temperature was in a range of 17°C to 27°C. Apart from the heat loss of the sleeping thermal manikin, the velocity distributions and temperature distributions were also measured in the experiments for subsequent analysis.

Keywords: Sleeping Environment, Mixing Ventilation System

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Authors: T. Delval, C. Sauvage, Q. Jullien, R. Viano, T. Diallo, B. Collignan, G. Picinbono

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In the context of the international spread of COVID-19, the Centre Scientifique et Technique du Bâtiment (CSTB) has led a joint research with the French government authorities Hauts-de-Seine department, to analyse the risk in school spaces according to their configuration, ventilation system and spatial segmentation strategy. This paper describes the main results of this joint research. A multidisciplinary team involving experts in indoor air quality/ventilation, pedestrian movements and IT domains was established to develop a COVID risk analysis tool based on Building Information Model. The work started with specific analysis on two pilot schools in order to provide for the local administration specifications to minimize the spread of the virus. Different recommendations were published to optimize/validate the use of ventilation systems and the strategy of student occupancy and student flow segmentation within the building. This COVID expertise has been digitized in order to manage a quick risk analysis on the entire building that could be used by the public administration through an easy user interface implemented in a free BIM Management software. One of the most interesting results is to enable a dynamic comparison of different ventilation system scenarios and space occupation strategy inside the BIM model. This concurrent engineering approach provides users with the optimal solution according to both ventilation and pedestrian flow expertise.

Keywords: BIM, knowledge management, system expert, risk management, indoor ventilation, pedestrian movement, integrated design.

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Authors: Ranojoy Dutta, Adam Barker

Abstract:

Multifamily residential buildings are increasingly being built with large glazed areas to provide tenants with greater daylight and outdoor views. However, traditional double-glazed window assemblies can lead to significant thermal discomfort from high radiant temperatures as well as increased cooling energy use to address solar gains. Dynamic glazing provides an effective solution by actively controlling solar transmission to maintain indoor thermal comfort, without compromising the visual connection to outdoors. This study uses thermal simulations across three Canadian cities (Toronto, Vancouver and Montreal) to verify if dynamic glazing along with operable windows and ceiling fans can maintain the indoor operative temperature of a prototype southwest facing high-rise apartment unit within the ASHRAE 55 adaptive comfort range for a majority of the year, without any mechanical cooling. Since this study proposes the use of natural ventilation for cooling and the typical building life cycle is 30-40 years, the typical weather files have been modified based on accepted global warming projections for increased air temperatures by 2050. Results for the prototype apartment confirm that thermal discomfort with dynamic glazing occurs only for less than 0.7% of the year. However, in the baseline scenario with low-E glass there are up to 7% annual hours of discomfort despite natural ventilation with operable windows and improved air movement with ceiling fans.

Keywords: Electrochromic, operable windows, thermal comfort, natural ventilation, adaptive comfort.

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Authors: Oguz Ustun, Erdal Bekiroglu

Abstract:

In the present study, position estimation of switched reluctance motor (SRM) has been achieved on the basis of the artificial neural networks (ANNs). The ANNs can estimate the rotor position without using an extra rotor position sensor by measuring the phase flux linkages and phase currents. Flux linkage-phase current-rotor position data set and supervised backpropagation learning algorithm are used in training of the ANN based position estimator. A 4-phase SRM have been used to verify the accuracy and feasibility of the proposed position estimator. Simulation results show that the proposed position estimator gives precise and accurate position estimations for both under the low and high level reference speeds of the SRM

Keywords: Artificial neural networks, modeling andsimulation, position observer, switched reluctance motor.

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Authors: Geun-Mo Kim, Young-Jae Ryoo

Abstract:

In this paper, an automatic guided mobile robot using a new magnetic position meter is described. In order to measure the lateral position of a mobile robot, a new magnetic position meter is developed. The magnetic position meter can detect the position of a magnetic wire on the center of road. A mobile robot in designed with a sensing system, a steering system and a driving system. The designed mobile robot is tested to verify the performance of automatic guidance.

Keywords: Autonomous vehicle, magnetic position meter, steering, magnet.

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