Internal Ventilation Research Articles

Sound insulation characterisation of innovative natural ventilated façade in the context of living lab installations

Building acoustic standards like EN 14351 and ISO 10140 regulate the measurement of sound insulation of transparent elements, with indications of the test sample dimensions, test conditions, and criterions of adaptations of the results to different on-site conditions. However, given the research on innovative transparent building envelope including internal ventilation as double skin facades, these methodologies present limitations related to the characterization of the high variability of operating conditions in real in-field conditions. To this aim the acoustic performance could be explored with more flexible methods inside the multi-domain context of Living Labs, which present an opportunity for multiple characterizations and testing costs reduction. This work investigates the possibility of using the sound-intensity probe method to evaluate the airborne sound insulation of a transparent building element with internal ventilation. For this purpose, a comparative measurement campaign has been performed on the same building element installed in two Living Labs. The results show good compatibility between the different measurements and scales supporting the application of this methodology for comparative studies in the perspective of innovative building components measurements, and the application in Living Labs.

Impact of Indoor Plants on Human Health: A Review

One of the goals of a construction was to have a sustainable and healthy interior, something that engineers took seriously when creating and utilizing it. Physical approaches can be used to design arrangements, such as in the layout arrangements, lighting, and air reflections. Still, there has been a fierce pushback against the natural approach paradigm. This paper addresses the greening of interior spaces as a means of preserving and improving the quality of interior spaces. The sick-structure pattern, disinclinations, nasal and ocular vexations, and respiratory dysfunction, including unseasonable fatalities, have all been linked to poor IAQ. The use of phytoremediation is a novel method to lessen air adulterants and improve IAQ by absorbing, adsorbing, assimilating, or transferring them. Thus, the current review's goal is to investigate the role that inner sources play in perfecting inner air quality, including their sanctification capabilities. There’s adding substantiation that colorful factory species or their corridor can reliably reduce the attention of multitudinous air adulterants in the inner medium and promote mortal good. still, the inner air adulterant junking effectiveness depends on the species of the factory, and colorful factory characteristics like splint size, consistency, area, photosynthetic exertion, and light intensity. One of the cheapest and most reliable ways to create a healthier inner terrain is by using inner shops. If more focus is put on developing a biophilic environment and increasing the usage of inner stores, more public health can be maintained at a lower cost and with less load on the health care system. As of yet, no standards have been set for fashionable interior stores or how they affect vibrant elements like internal ventilation, moisture content, and temperature. Thus, further experimental exploration is demanded that simulates the interior terrain to cover the impacts of inner shops on factors like moisture, temperature, and ventilation., in perfecting the medium of unrestricted space.

Numerical study on the internal ventilation of the engine room of a ship under construction

Manual welding operations are performed inside the engine room of a liquefied natural gas carrier under construction. The welders are at risk of exposure to welding fumes in case of poor ventilation. Therefore, ventilation fans are installed at shipbuilding sites to improve indoor air quality. Although ensuring the respiratory health of welders is important, studies focusing on ventilation in the ship engine room have not been conducted. Therefore, the ventilation efficiency was evaluated herein based on the placement of ventilation fans to alleviate air stagnation using a computational fluid dynamic (CFD) model operating on Fluent. The mean age of air (MAA) was computed to assess the ventilation efficiency. In addition, particles with size and physical properties similar to welding fumes were sourced assuming 30 welders in the engine room. Results revealed that ventilation fan and/or exhaust in enclosed spaces contributes significantly to alleviating the MAA level. MAA and particle distribution did not correlate well due to the different properties of air and the iron oxide particle. Therefore, to determine the optimal ventilation fan displacement, particle motion should be studied along with performing MAA analysis. The proposed CFD model potentially guides to improvement of the working environments and respiratory health of welders.

Research Progress of Enhanced Thermal Evacuation and Cooling Technology for High-Speed Motors

In high-speed motors, there is a huge amount of heat generation from core and winding losses, which may result in thermal failures or motor performance deterioration. In the prevention of heat accumulation, efficient cooling technology is critical for smooth and reliable motor movement. This paper summarizes the diverse application of high-speed motor and thermal requirements, such as in electrical devices, turbo-machinery, and high-precision machine tools. Three paths of case convection—cooling, internal ventilation cooling and spindle core cooling—are analyzed. Methods for configuring thermal resistance and improving cooling efficiency are summarized. Among them, coolant flow characteristics and flow channel shapes, gas supply ventilation systems, and methods to reduce air resistance, as well as axial cooling and integrated heat pipe structures, are extensively investigated. Finally, the development prospects of high-speed motor cooling are also forecasted. At present, the primary research directions are to reduce the heat generated by the heat source, utilize the latent heat of the coolant, optimize the cooling flow path of the shell, design an axial air-cooling circulation system, and enhance the heat dissipation of the spindle.

An overcooled coarse‐grained talus slope at low elevation: New insights on air circulation and environmental impacts, Cannon Cliff, New Hampshire, USA

AbstractOvercooled talus slopes are generally described as islands of sporadic permafrost below the lower alpine limit of permafrost. The negative thermal anomaly of the ground is mainly consecutive to the internal ventilation of the deposit, but it is also conditioned by multiple factors as topography, slope aspect and incline, openwork structure and coarseness of the deposit, air temperature, solar radiation and wind regime. Therefore, the study of the spatiotemporal dynamics of ventilation processes allows a better understanding of the phenomenon. At Cannon Cliff, New Hampshire (USA), several field visits and environmental monitoring allowed us to describe the varying nature and significance of the ventilation mechanisms that can be observed at the ground surface and associated with both the intensity and direction of the airflows in a talus debris accumulation/protalus rampart system. The thermal negative anomalies are strong enough to lower the ground temperature to the point of preserving ice during the late spring and summer seasons. The monitoring of the gradient between external (air) and internal (talus) temperatures coupled with several dendroecological and geomorphological analyses provided a complete environmental picture of the impacts, feedback and extent of the phenomenon.

A Comparative Numerical Study of Lithium-Ion Batteries with Air-Cooling Systems towards Thermal Safety

Given the growing demand for increased energy capacity and power density in battery systems, ensuring thermal safety in lithium-ion batteries has become a significant challenge for the coming decade. Effective thermal management plays a crucial role in battery design optimization. Air-cooling temperatures in vehicles often vary from ambient due to internal ventilation, with external air potentially overheating due to vehicle malfunctions. This article highlights the efficiency of lateral side air cooling in battery packs, suggesting a need for further exploration beyond traditional front side methods. In this study, we examine the impact of three different temperature levels and two distinct air-cooling directions on the performance of an air-cooling system. Our results reveal that the air-cooling direction has a more pronounced influence compared with the air-cooling temperature. By employing an optimal air-cooling direction and ambient air-cooling temperature, it is possible to achieve a temperature reduction of approximately 5 K in the battery, which otherwise requires a 10 K decrease in the air-cooling temperature to achieve a similar effect. Therefore, we propose an empirical formula for air-cooling efficiency under various conditions, aiming to provide valuable insights into the factors affecting air-cooling systems for industrial applications toward enhancing the fire safety of battery energy storage systems.

Numerical simulation of aerodynamics in the cabin of transport

One of the most important tasks of transport engineering is the task of providing optimal and comfortable conditions for drivers and passengers, in particular: temperature, pressure, dust content, humidity, air speed, noise, illumination, etc. Temperature, humidity and vibration influences are also of great importance for the functioning of electronic devices and transport equipment. In this paper, a numerical-mathematical model is presented for studying the fields of temperatures, velocities, pressures, densities and humidity of air in the cabin space with simultaneous blowing by an external flow and internal ventilation. As a mathematical model, the Navier-Stokes equations in the RANS formulation are used, together with the diffusion equation, which allows calculating the mass fractions of water vapor in the domain. As a numerical implementation, the finite volume method is used together with turbulence models in the Ansуs Fluent software product. A non-stationary setting is considered, the stabilization time of flows is found; the stabilized fields are compared with the results obtained for the stationary setting. A method for obtaining numerical values of heat transfer coefficients for walls consisting of several layers of materials is also given. As a numerical experiment, a cabin of a special technological transport with a large glass area and multi- layered walls, with one driver without passengers, is considered. The obtained results are compared with the results obtained earlier without taking into account the diffusion equation and relative air humidity modeling.

Simulation and Optimization Study on the Ventilation Performance of High-Rise Buildings Inspired by the White Termite Mound Chamber Structure.

High-rise buildings often use mechanical systems to assist ventilation to maintain the stability of their internal environments, and the energy consumption of mechanical ventilation poses a great challenge to urban environments and energy systems. The ventilation system of termite mounds with a combination of internal main and attached chambers is one of the classic examples of nature's bionic approach to maintaining a stable internal ventilation environment for large-volume structures. In this study, based on the inspiration of the internal ventilation chamber structure of bionic termite mounds, we constructed seven high-rise building chamber ventilation models based on the chamber structure of termite mounds with main chambers, main chambers plus single-attached chambers (three types), and main chambers plus double-attached chambers (three types) under natural ventilation conditions, aiming at obtaining the optimal low-energy and high-efficiency chamber ventilation model for bionic termite mounds in high-rise buildings. (1) The wind speed and wind pressure of the high-rise building with the addition of the bionic termite mound chamber structure is higher than that of the traditional chamber-free high-rise building in the sample floors, the maximal difference of the wind speed between the two models is 0.05 m/s, and the maximal difference of the wind speed of the single building is 0.14 m/s, with the maximal difference of the wind speed of the single building being 0.14 m/s; and the natural ventilation environment can be satisfied by a high-rise building with a chamber. (2) After increasing the single-attached chamber structure of the bionic termite mound, the difference in wind speed of different floors is 0.15 m/s, which is 0.10 m/s higher than that of the high-rise building model with the main chamber only. (3) Under the bionic termite mound chamber high-rise building double-attached chamber model, the maximum difference in wind speed of each floor sampling point can reach 0.19 m/s, while the wind pressure cloud map shows a stable wind environment system. (4) Two attached chambers are added at A and B of the high-rise building to form the a4 model of the chamber of the high-rise building with a double-chamber bionic termite mound. According to the results, it can be seen that the model of the nine floor sampling points of the maximum wind speed difference has six places for the highest value, and the single building wind speed difference for the minimum value of 0.10 m/s. The study aims to optimize the connectivity and ventilation performance of high-rise buildings under natural ventilation conditions and to promote the green and sustainable design of high-rise buildings.

Characterisation of flow dynamics within and around an isolated forest, through measurements and numerical simulations

The case study of ‘Bosco Fontana’, a densely-vegetated forest located in the north of Italy, is analysed both experimentally and numerically to characterise the internal ventilation of a finite forest with a vertically non-homogeneous canopy. Measurements allow for the evaluation of the turbulent exchange across the forest canopy. The case study is then reproduced numerically via a two-dimensional RANS simulation, successfully validated against experimental data. The analysis of the internal ventilation leads to the identification of seven regions of motion along the predominate-wind direction, for whose definition a new in-canopy stability parameter was introduced. In the vertical direction, the non-homogeneity of the canopy leads to the separation of the canopy layer into an upper foliage layer and a lower bush layer, characterised respectively by an increasing streamwise velocity and turbulence intensity, and a weak backflow. The conclusions report an improved description of the dynamic layer and regions of motion presented in the literature.

Natural Ventilation in Low-Cost Housing: An Evaluation by CFD

With the spread of sustainability concepts, due to the global energy crisis and the unrestrained consumption of natural resources, the importance of rational use and reduction of energy consumption has been intensified, albeit in short steps. This concern has taken up bioclimatic concepts in buildings, especially housing buildings for low-income people, aiming at improving the quality of housing production in terms of its habitability. The objective of this research is to theoretically and experimentally study the natural ventilation in a housing building, which fits into the low-cost pattern. The use of Computational Fluid Dynamics to predict natural ventilation was adopted as a tool to perform these analyses. Experiments were carried out by visiting the study area to collect data on air velocity, temperature, and relative humidity in all rooms of the residence in order to carry out the intended analyses. Computer simulation of natural ventilation considering the building with the doors and windows open and with fixed geometry was performed. Results proved that the proposed mathematical model was able to reproduce, with rich details and physical coherence, the internal and external air flow inside the building, indicating better internal ventilation performance in environments that have door and window openings, with recesses, revealing the importance of cross ventilation to reduce the internal temperature and consequent improvement in thermal comfort. The idea is to help civil engineers and specialists in the economically viable design of low-cost buildings from the economic, social, and thermal comfort points of view.

MZ세대의 퍼스널 트레이닝 센터 선택속성에 대한 IPA 분석 : 부산지역을 중심으로

Purpose: The purpose of this study is to present a generation MZ inflow strategy and a plan to establish and improve a new marketing strategy by analyzing the attributes of training centers recognized s important by generation MZ users, using the importance-performance analysis (IPA).BR Method: To achive this, 332 users of the generation MZ who utilized a personal training center in the Busan area were selected as subjects, and a questionnaire was sued to collect data. Data processing involved the use of SPSS Window Version 28.0, and involved reliability analysis, exploratory factor analysis, frequency analysis, paired-sample t-test, and IPA analysis.BR Results: The study revealed that the following attributes were important for generation MZ users: leader’s personality and communication style, sincere guidance from the leader, long-term discounts and event benefits, home accessibility, and provision of free sportswear and towels (quadrant 1). Additionally, cleanliness of changing rooms and shower rooms and internal temperautre and ventilation facilities were also found to be important (quadrant 2). Safety facility and emergency supplies, parking lot availability, onetime experience cost, one-month use cost, one-time PT cost, and vending machine availability were also important (quadrant 3). Lastly, the appearance, career and academic background of the leader, and convenience of public transportation were idenBR Conclusion: Based on these results, it can be concluded that generation MZ users value facility cleanliness and internal ventilation when selecting a personal training center. Therefore, it is recommended that feedback from the MZ generation be utilized to improve the hygiene and cleanliness of facilities, by reflecting the characteristics of this generation who are familiar whit social media and frequently share their experiences. Additionally, an indoor space can be provided for MZ generation’s social media activities, as this can lead to effective marketing through this group.

Improving indoor air quality in primary school buildings through optimized apertures and classroom furniture layouts

This study aimed to examine the influences of the opened to total aperture area (the O/A ratio) and furniture arrangements in a naturally ventilated classroom’s internal ventilation and PM 2.5 deposition. For the experiments, four cases were established for the O/A ratio and layout. Computational fluid dynamics (CFDs) was validated and applied, using the ANSYS Fluent software, to determine the velocity and concentration of PM 2.5 in the primary school classroom. The results indicated that different furniture arrangements and O/A ratios affected the air velocities and PM 2.5 concentrations, and could improve indoor air quality. The furniture arrangement affected the PM 2.5 concentration at a height of 0–1.6 m, and concentrations at the inlet and outlet, as well as near the classroom wall, which were higher than that in the center. The U-shaped layout reduced the concentrations of PM 2.5 and the natural air in the classroom, yielding a minimum vertex in the middle of the classroom, particularly in the breathing zone of elementary students. Moreover, the indoor PM 2.5 concentration increased, with an increasing ratio of apertures in the classroom. An O/A ratio of 1 corresponded to the highest air velocity and PM 2.5 concentration in the classroom, with high turbulence in the middle. A ratio of 0.25 corresponded to the least PM 2.5 concentration in the classroom, particularly at below 2 m. Thus, applying the optimized results, an O/A ratio of 0.25 and the U-shaped furniture layout, to a classroom significantly lowered its PM 2.5 concentrations. • Primary school students are severely affected by air pollution in Chiang Mai. • Inexpensive and facile strategies necessary for reducing the PM2.5 concentrations. • Effects of the O/A ratio and furniture layouts on PM2.5 deposition are studied. • Computational fluid dynamics was applied employing the Ansys Fluent software. • Optimized results significantly lowered the PM2.5 concentrations of the room.

Modeling of Flow Heat Transfer Processes and Aerodynamics in the Cabins of Vehicles

Ensuring comfortable climatic conditions for operators in the cabin of technological machines is an important scientific and technical task affecting operator health. This article implements numerical and analytical modeling of the thermal state of the vehicle cabin, considering external airflow and internal ventilation. A method for calculating the heat transfer coefficients of a multilayer cabin wall for internal and external air under conditions of forced convective heat exchange is proposed. The cabin is located in the external aerodynamic flow to consider the speed and direction of the wind, as well as the speed of traffic. Inside the cabin, the operation of the climate system is modeled as an incoming flow of a given temperature and flow rate. The fields of velocities, pressures, and temperatures are calculated by the method of computer hydrodynamics for the averaged Navier–Stokes equations and the energy equation using the turbulence model. To verify the model, the values of the obtained heat transfer coefficients were compared with three applied theories obtained from experimental data based on dimensionless complexes for averaged velocities and calculated by a numerical method. It is shown that the use of numerical simulation considering the external air domain makes it possible to obtain more accurate results from 5% to 75% compared to applied theories, particularly in areas with large velocity gradients. This method makes it possible to get more accurate values of the heat transfer coefficients than for averaged velocities.

Research on the Planning of an Urban Ventilation Corridor Based on the Urban Underlying Surface Taking Kaifeng City as an Example

With the rapid development of urbanization, various urban problems such as air pollution, urban heat islands, poor ventilation, and so on have followed. Ventilation corridors can improve the internal ventilation conditions of a city and can effectively alleviate these urban problems. Taking Kaifeng as an example of a medium-sized city, this study used meteorological analysis and remote sensing (RS) technology and a geographical information system (GIS) to plan ventilation corridors. Through analysis of the thermal environment, the influential factors of the underlying surface (building density, road length, water length, vegetation coverage) and wind environment in Kaifeng, the compensation space and action space, and the comprehensive values of the ventilation potential in each region were determined. The results show that with the use of the single-window algorithm and Landsat8 data, high-resolution ground temperature can be retrieved. Moreover, although the ventilation potential value of Kaifeng in the northern part is better than that in the southern part, the temperature in the north is higher than that in the south. Through comparison and analysis of the location of the low-temperature zone, the air duct opening of the ventilation corridor can be determined and the source areas of three ecological ventilation corridors identified. According to the ventilation corridor air duct opening, the urban underlying surface and the dominant wind direction of Kaifeng city, two ventilation corridors located on the eastern and western sides of Kaifeng city were planned. This urban ventilation corridor planning method, which is based on temperature difference analysis and determination of the source area of the ventilation corridor, can provide a reference for the construction of an ecologically livable city.

Analysis of the effects of shading screens on the microclimate of greenhouses and glass facade buildings

Shading devices are widely used in the Mediterranean area, since they reduce strong solar radiation effects in the closed environment. On the contrary, they have negative effects on the internal ventilation, especially if they have low porous texture limiting the air exchange with the external environment. This work aims to characterize by means of computational fluid dynamics the microclimate given by the use of shading devices in buildings with glass envelopes, such as greenhouses. The method is applied to a naturally ventilated glass greenhouse. Three commercial shading screens are compared, having typical porosity for the use in Mediterranean climate. The screens are modeled by means of porous materials, with the properties evaluated by experimental measurements of permeability. The numerical simulations are verified by a comparison with measurements of temperature and velocity within the greenhouse. In particular, the experimental setup is based on a novel and patented methodology which gives the exact position of the sensors within the greenhouse thanks to an acoustic referencing system. It is shown that screens with low permeability give optimal temperature distribution above the crops for the wind and air temperature conditions analyzed. The best screen position and permeability, for the environmental most frequent conditions in terms of solar radiation and wind directions with respect to orientation and position of the windows, were established. The methodology and the results shown in the work can be applied to different glass envelope buildings, to yield the best choice of shading screens in correspondence of given environmental characteristics.

Development and Eevaluation of HMD with Internal Ventilation Function using Small Blower

Development and Eevaluation of HMD with Internal Ventilation Function using Small Blower

Controlling energy consumption in residential buildings using air infiltration in humid climates

Given the ever-increasing people’s need for housing, affordable housing and environmental comfort are important, and the use of inactive design methods is the cheapest solution to achieve low-energy buildings. This study aimed at understanding the natural ventilation potential in Gorgan. This research has been conducted aiming at providing solutions based on airflow to reduce energy consumption in the building for the warm months of the year. Solutions for using natural ventilation in the design of a residential complex include a terrace, void, direct ventilation for the corridors, cross ventilation, and arranging the units to get suitable ventilation. The energy influence the air through the intermediate spaces of the floor units; as the external consumption during the warm period of the year was simulated in the form of an applied project. In this research, a model with mechanical ventilation and 4 patterns of 22 modes were designed using natural ventilation. The results showed that the factors such as using void, stair layout of the plan, using semi-empty spaces in the building, creating internal lateral ventilation, being the interior doors opened, placing the smaller unit from west to south, the connection between the kitchen and the living space in the building causes a reduction of the energy consumption in the warm seasons of the year in moderate and humid climates.

COMPUTATIONAL ANALYSIS OF LOAD VENTILATION IN BROILER TRANSPORT

The characterization of ventilation during the transport of broiler chickens is essential for identifying and characterizing the potential problems of a convective heat flow and its effects on the welfare and the health and production conditions of the chickens. The objective of this study was to evaluate the ventilation patterns in two layout models of a live transport load: conventional (LC) and alternative (LA) with spacers placed between the chicken transport crates. Computational fluid dynamics (CFD) simulations and wind tunnel tests were performed using small scale models. The results showed that the use of spacers between crates (LA model) modified the ventilation patterns and increased the wind circulation between crates. However, wind tunnel tests simulating a density of eight birds/crate were inconclusive because the ventilation was below the sensitivity of the measuring devices used (0.001 m/s). It can be concluded that the use of spacers between the transport crates can modify the ventilation patterns within the load and increase the air circulation between the crates. However, the internal ventilation within the crates has not changed, suggesting the need for studies on the aerodynamics of a transport crate for poultry use.

Rock glaciers and related cold rocky landforms: Overlooked climate refugia for mountain biodiversity.

Mountains are global biodiversity hotspots where cold environments and their associated ecological communities are threatened by climate warming. Considerable research attention has been devoted to understanding the ecological effects of alpine glacier and snowfield recession. However, much less attention has been given to identifying climate refugia in mountain ecosystems where present-day environmental conditions will be maintained, at least in the near-term, as other habitats change. Around the world, montane communities of microbes, animals, and plants live on, adjacent to, and downstream of rock glaciers and related cold rocky landforms (CRL). These geomorphological features have been overlooked in the ecological literature despite being extremely common in mountain ranges worldwide with a propensity to support cold and stable habitats for aquatic and terrestrial biodiversity. CRLs are less responsive to atmospheric warming than alpine glaciers and snowfields due to the insulating nature and thermal inertia of their debris cover paired with their internal ventilation patterns. Thus, CRLs are likely to remain on the landscape after adjacent glaciers and snowfields have melted, thereby providing longer-term cold habitat for biodiversity living on and downstream of them. Here, we show that CRLs will likely act as key climate refugia for terrestrial and aquatic biodiversity in mountain ecosystems, offer guidelines for incorporating CRLs into conservation practices, and identify areas for future research.

Real-time ventilation control based on a Bayesian estimation of occupancy

Demand-controlled ventilation (DCV) is commonly implemented to provide variable amounts of outdoor air according to an internal ventilation demand. The objective of the present study is to investigate the applicability and the performance of occupancy-based DCV schemes in comparison with time-based and CO2-based DCV schemes. To do this, we apply the occupancy estimation method by the Bayes theorem to control the ventilation rate of an office building in real-time. We investigated six cases in total (two cases for each control scheme). Experiments were conducted in a small office room with controllable ventilation equipment and relevant sensors. The observed results indicated that the occupancy-based schemes relying on Bayes theorem could be applied successfully to perform continuous control of ventilation rates without causing recursive problems. Additionally, we discussed the time delays associated with the control procedure, including dispersion time, sensor-response time, and data processing time. Finally, we compared the performance of the proposed approach in six DCV cases in terms of a resultant indoor CO2 level and the total ventilation-air volume. We concluded that DCV control based on both occupancy and floor area provided the best conformity to the ASHRAE standard among the analyzed schemes.