Efficient Airflow Research Articles

Experimental Mouse Models and Human Lung Organoid Models for Studying Chronic Obstructive Pulmonary Disease.

Chronic obstructive pulmonary disease (COPD), a leading cause of morbidity and mortality throughout the world, is a highly complicated disease that includes chronic airway inflammation, airway remodeling, emphysema, and mucus hypersecretion. For respiratory function, an intact lung structure is required for efficient air flow through conducting airways and gas exchange in alveoli. Structural changes in small airways and inflammation are major features of COPD. At present, mechanisms involved in the genesis and development of COPD are poorly understood. Currently, there are no effective treatments for COPD. To develop better treatment strategies, it is necessary to study mechanisms of COPD using proper experimental models that can recapitulate distinctive features of human COPD. Therefore, this review will discuss representative established mouse models to investigate inflammatory processes and basic mechanisms of COPD. In addition, human COPD-mimicking human lung organoid models are introduced to help researchers overcome limits of mouse COPD models.

Development and evaluation of a buoyancy-driven airflow window with multioperation modes

This study introduces a novel, cost-effective window-integrated passive system (WIPS) that enhances indoor air quality and maintains comfortable temperatures throughout both summer and winter. The WIPS utilizes buoyancy-driven air flow through dual air cavities that alternately preheat or cool the incoming air depending on the season. The system’s design was optimized for Seoul, Korea, through computational fluid dynamics (CFD) simulations using Fluent 2021 R2 software, which employed a Reynolds-Averaged Navier-Stokes (RANS) model with RNG κ-ε turbulence modeling. Key design adjustments included the use of glass and unplasticized polyvinyl chloride (UPVC) to minimize unintended airflow, as well as modifications to the geometry and size of the air cavities to maximize efficient air flow and thermal effectiveness. The optimized design demonstrated significant improvements in thermal performance, achieving a preheating effect up to 35 °C in winter and reducing indoor temperatures by 10 °C in summer. These results underline the potential of WIPS to provide a sustainable solution for building ventilation and climate control.

ANALYSIS OF ENGINEERING ECONOMICS OF THE NEW ERA COMPARED WITH THE CONVENTIONAL MATERIALS USED IN HVAC DUCT APPLICATION

Selecting suitable materials for air ductwork is essential to ensure efficient airflow distribution and reduce economic costs, as it directly impacts an air conditioning system’s overall performance and functionality. The PVC-coated polyester canvas and foam materials have revolutionized the construction of air ductwork, offering numerous benefits and advantages over conventional materials. For instance, these materials have been successfully used in the construction of air ducts for large commercial buildings, resulting in significant energy savings and improved indoor air quality. Using these new-era materials has design flexibility, durability, energy efficiency, and cost-effectiveness. This research has provided a comprehensive analysis of the economic cost of the new era of air ductwork compared with conventional air ductwork in Thailand, and the thorough assessment of total service life costs has improved on the financial implications of adopting this new technology. The economic analysis of PID ducts reveals their cost-effective excellence compared to other investment types. The benefit-cost ratio of 4.73 and a payback period of 1.48 years show the financial advantages offered by PID ducts. With their affordability, efficiency, and simplicity, PID ducts emerge as the most attractive option for investors seeking long-term profitability and sustainability in construction projects.

Simulation study of dynamic building insulation with transpired solar collectors

This study conducts a comprehensive numerical analysis using Ansys Fluent to investigate the thermal behaviour of transpired solar collectors (TSCs) focusing on temperature distribution, airflow dynamics, and heat recapture capabilities. The research evaluates TSC performance across various environmental conditions. A significant observation from the study is the TSCs' ability to recapture heat losses from the enclosures during nighttime, particularly under higher airflow conditions, where TSCs effectively redirect heat back into building spaces, contributing to energy conservation. Subsequently, the study reveals an inverse relationship between solar radiation levels and TSC efficiency in heat loss recapture. As solar radiation increases from 200 W/m2 to 1000 W/m2, the recaptured wall heat loss decreases by a percentage, ranging from 125 % to 241 % compared to the maximum observed during nocturnal periods. Additionally, the temperature analysis of the TSC backplate demonstrates a complex thermal response under different operational conditions. Solar radiation, airflow rates, and environmental properties influence this interplay. The study also uncovers a consistent linear increase in airflow velocity from the inlet to the outlet within the TSC air cavity, suggesting efficient airflow management. This insight is crucial for optimizing TSC design for improved heat exchange efficiency. In conclusion, the findings of this research offer valuable insights into the operational dynamics of TSCs, highlighting the importance of environmental factors in their design and functionality.

3D spacer fabric structured airflow channel for enhanced solar desalination with efficient multi-energy harvesting

Solar steam generation (SSG) is a sustainable way to drive seawater desalination and wastewater purification with green environmental energies including solar radiation, ambient heat, and airflow. Airflow is ubiquitous in outdoor environments, however, the utilization of airflow for accelerated evaporation through structure engineering remains unclear. Herein, environmental energies are efficiently utilized in an integrated way with the rational design of 3D spacer fabric. Carbon fiber bundles with broadband photothermal conversion ability and Tencel yarns with superior hydrophilicity are fabricated into the 3D spacer fabric. The stereoscopic airflow channel, wide evaporation surface area, and separated layers are constructed to optimize airflow pathways. Heat loss is reduced through the accelerated evaporation cooling effect. Extra ambient heat is harvested for cold evaporation by efficient airflow utilization. The evaporation rate of 3D spacer fabric reaches 5.15 kg·m−2·h−1 under a convective airflow of 3.5 m·s−1, which is twice the rate of traditional plain fabrics. The outstanding salt resistance is realized due to the separate design of photothermal and water supply layers as well as the continuous water circulation. The structural engineering of condenser devices is also investigated for enhanced airflow utilization. Overall, this work presents an effective and comprehensive multi-energy harvesting strategy to achieve rapid and durable SSG for practical clean water production.

Numerical Simulation of a Efficient Solar-Powered Ventilation System

The objective of this study is to conduct a numerical analysis of a small-scale solar ventilation-air conditioning system operating under the meteorological conditions of Bisha, Saudi Arabia. The primary objective of the proposed system is to provide sustainable and comfortable thermal conditions. To achieve this objective, the system recovers the heat wasted by the solar ventilation process and reuses it to power the desiccant dehumidification process. The solar chimney features a lateral (vertical) wall design, and a comparative performance investigation of two solar chimney designs (conventional vs original) is conducted. Mathematical models of the ventilated room and solar chimney are developed, and numerical simulations are carried out to evaluate the performance of each solar chimney design. The study aims to assess the ability of each design to maintain indoor thermal comfort through the analysis of air distribution temperature and air streamlines. The results of the performance comparison revealed that the proposed solar chimney design outperformed the conventional design in terms of thermal and ventilation performance. The proposed solar chimney design, with its lateral (vertical) wall, was also found to be more effective in maintaining indoor thermal comfort than the conventional design. The simulations showed that the proposed design produced a more uniform air distribution temperature within the ventilated room, resulting in improved comfort levels. Additionally, the proposed design was found to have a more efficient airflow pattern, with fewer areas of stagnant airflow. These results suggest that the proposed solar ventilation-air conditioning system has the potential to provide sustainable and comfortable thermal conditions in small-scale buildings.

A novel method to assess heat transfer and impact of relevant physicochemical parameters for the scaling up of solid state fermentation systems

Heat production during fermentation is undesirable. It can affect the growth of biomass, sporulation, products formation and the scaling-up. Physico-chemical properties of substrates influence heat and mass transfer in Solid State Fermentation. Heat is chemically produced into substrates without micro-organism to allow better reproducibility. A 24–1 fractional factorial design is chosen to study the influence of four physicochemical parameters on heat transfer: Granulometry, Bulk Density, Carr Index (compressibility index) and Water Absorption Capacity. Results show that the two main physicochemical parameters which influence heat transfer are Granulometry and Carr Index. High Granulometry and low Carr Index have influence on maximum temperature reached during the test, warm-up speed and cooling speed. These two parameters allow efficient air flow through the substrate bed with large interparticle spaces enhancing exchange surface between air and particles. A substrate with these characteristics facilitates heat transfers in forced-aerated reactors.

Derivation of High-Resolution Meteorological Parameters for Use in Airport Wind Shear Now-Casting Applications

Methods for now-casting adverse weather conditions with the potential to cause disruption to aircraft landings often make use of real-time measurements at high temporal resolution. This paper describes processing methodologies developed to derive meteorological parameters from such measurements recorded in the vicinity of Hong Kong International Airport, specifically a radiometer in King’s Park, a wind profiler and surface anemometer on Cheung Chau Island and weather buoys in the Pearl River estuary. These parameters are suitable for use as input to a now-casting application of the computationally efficient airflow model, FLOWSTAR, which has previously been shown to predict mountain waves generated by flow over Lantau Island to the southeast of the airport. Radiosonde data from King’s Park have been used to test the radiometer processing method; the novel approach of using minimum and maximum potential temperature deviations from a series of height-dependent linear profiles to derive radiometer inversion layer parameters generates data that compares well with values derived from corresponding radiosonde profiles. Mountain wave strength depends on the magnitude of wind speed in the inversion layer; wind profiler data can be used to estimate typical and maximum wind speeds and associated wind directions using estimates of inversion layer depth derived from the radiometer data. With estimates of surface sensible heat flux appropriate for the airport’s coastal location calculated using a marine boundary layer scheme, a dataset of meteorological parameters at 20-min resolution has been derived for input into the FLOWSTAR model. The combination of automated meteorological data processing methods and flow field modelling has the potential to form part of a now-casting system for determining strong wind shear conditions at the airport.

Evaluation of fast fluid dynamics with different turbulence models for predicting outdoor airflow and pollutant dispersion

Fast fluid dynamics (FFD) could provide informative and efficient airflow and concentration simulation. The commonly used turbulence model in FFD was Re-Normalization Group (RNG) k-ε turbulence model which solved two transport equations to obtain eddy viscosity. To reduce this part of time and further improve computing speed, this investigation implemented no turbulence model, Smagorinsky model and dynamic Smagorinsky model which calculated eddy viscosity without solving equation in FFD in an open-source program, OpenFOAM. By simulating several outdoor cases of varying complexity and comparing with experiment and CFD, this study assessed the accuracy and computing efficiency of FFD with four turbulence models. Compared with CFD, FFD greatly improved the computing speed without reducing accuracy. The simulation of FFD without turbulence model was fast but inaccurate. FFD with Smagorinsky model increased the computing speed while ensuring the same accuracy as RNG k-ε turbulence model. FFD with dynamic Smagorinsky model provided accurate results with high efficiency. Computation errors arose mainly from inaccurate prediction of turbulence dispersion. The computing cost was associated with the number of transport equations and calculation method of model coefficient. This investigation recommended the use of FFD with dynamic Smagorinsky model for outdoor airflow and pollutant dispersion studies.

Optimal design of thin laminate plates for efficient airflow in ventilation via buckling

This work studies an optimal design problem to maximize the airflow opening of a thin-walled structure for efficient ventilation. The airflow opening is defined in terms of nodal displacements as the area swept by a deformed free edge, or the volume formed between the deformed and undeformed configurations or their combination. In this study, a novel formulation for the airflow opening in a plate or shell with large deflections is derived by using the principle of virtual work and the constructed generalized virtual force. In this formulation, the airflow opening can be evaluated via only two finite element analyses for one real and one virtual load cases. By using the present formulation, the maximum airflow problem is formulated as a topology optimization problem for a laminated thin-walled structure, and is subsequently solved by using a moving iso-surface threshold method. Numerical examples are presented for the optimum laminated flat plates of three edges simply supported and one edge free with designable and non-designable layers and under in-plane compression along the two opposite simply-supported edges. The numerical results show that the airflow opening can be maximized when the optimized laminated plate deforms in a shape similar to its critical buckling mode and the opening is much larger than that of the flat plate with the same amount of material and constant thickness.

A novel integrated fuzzy control system toward automated local airflow management in data centers

Today, Data Centers (DCs) are dynamic environments with considerable fluctuations in workload and power dissipation. As a result, active monitoring and dynamic thermal management strategies are essential. In this study, an automated dynamic airflow management technique using air dampers was introduced to manage cold air delivery to individual aisles based on the Information Technology Equipment (ITE) airflow demand. Within this management system, pressure measurements inside the Cold Aisle Containment (CAC) and the plenum were considered controlled variables. First, a feedback fuzzy controller was designed to regulate the airflow delivered to the aisles by adjusting the Open Area Ratio (OAR) of the air dampers. Then, to improve the system’s performance and to implement a control system which was adaptable to environmental changes, another fuzzy controller was developed to adjust the blower speed of the cooling units. To estimate the required airflow for provisioning all the ITE in a DC, an Artificial Neural Network (ANN) was developed to characterize the air dampers. This study experimentally examined several opportunities for improving the thermal management and energy performance of DCs with automatic control schemes. Experimental data showed that by using the proposed cooling control strategy, 75% of the cooling units’ blower powers and 16% of the chiller’s power were saved while maintaining proper thermal management conditions compared to the worst case scenario in which the air dampers were completely open and the cooling units’ blower speeds were at maximum. Experimental data from the implementation of the holistic control methodology indicated that there was minimal air leakage from the plenum to the room. Additionally, this approach achieved more efficient airflow delivery from CRAH units to the cold aisles with minimal air loss through leakage.

A new applied protocol concerning COVID-19`s pandemic control: “Outdoor Access Approach” remodel of living for ensuring better ventilation

COVID-19 is a mucoso-respiratory highly contagious disease that has leaded to a tremendous global pandemic wide spreading throughout nations of all continents with successive waves of high morbidities and mortalities. However, several independent vaccine production projects are working ahead for combatting the pandemic, but it is obvious they cannot create a sufficient umbrella that could protect billions of humans in a short term. Indeed, the current approved protocols including frequent cleaning of hands, social distancing and covering face mask are disappointing for their claimed capabilities to efficiently control of the pandemic. As they failed to highlight the critical determining role of air refreshing into indoors that 90 percent of infected people at least involved in enclosed spaces. Instead, Outdoor Access Approach (OAA) can be promising according veterinary medical successful experiences in control of air-borne contagious diseases as control of highly pathogenic avian influenza to become a global pandemic (One Health integration). Along with the above-mentioned protocols. Adaptation of all aspects of ordinary life activities in human societies to guarantee an efficient fresh air flow into enclosed spaces and prevention of the most dangerous air stagnation in them is the core stone of the OAA. This article discusses practical suggestions to attain such situation which can provide a kind of symbiosis with COVID-19` infection major threatening.

Spontaneous exfoliation and tailoring derived oxygen-riched porous carbon nanosheets for superior Li+ storage performance

2D carbon nanosheets are promising electrode materials for high-efficiency lithium ion batteries (LIBs). However, the bottleneck in this field is how to obtain high quality carbon nanosheets via a scalable and facile procedure while well-maintaining superior Li+ storage performance. Herein, an efficient airflow annealing method to prepare porous carbon nanosheets (PCNs). The structure characteristics and electrochemical properties of PCNs have been fully investigated. The airflow annealing induces ultrathin porous nanosheets with rich oxygen-containing functional groups, which not only provide facile channels for the migration of Li+ ions and charge electron but also greatly improve the surface wettability and active sites. As a result, the PCNs anode exhibits a superior Li+ storage performance, including outstanding reversible capacity (782 mA h g−1), high Li+ diffusion coefficient (5.1 × 10−13 cm2 s−1), excellent rate (294.3 mA h g−1 at 2 A g−1) and cycle performance (742.8 mAh g−1 at 0.1 A g−1 after 100 cycles), outperforming previously reported biomass-carbon anodes. Considering the facile fabrication procedure and excellent electrochemical performance, this work throws light on a new avenue for the development of carbon materials for high-performance energy storage devices.

Numerical analysis of the methods for reducing the energy use of air-conditioning systems in non-uniform indoor environments

Previous studies have shown that using efficient airflow distributions for a non-uniform indoor environment can reduce the space cooling load significantly. However, the system cooling load (SCL) of air-conditioning is decreased only a little when the fresh-air ratio is small, causing the limited decrease in the air-conditioning system energy use (SEU). To fully exploit the energy-saving potentials of efficient airflow distributions to reduce the SEU, the SCL in a large-space building with different airflow distributions was simulated, and the SEU was compared between using a single cooling source and the multiple low-grade cooling sources to handle the air. The results show that (1) efficient airflow distributions actually provide the potentials of using the multiple low-grade cooling sources to handle the air; in contrast, using a single cooling source will abandon the potentials and result in little energy saving; (2) using multiple low-grade cooling sources for cooling the supply air, return air, and fresh air can make the potentials available, and the energy-saving rate could be 13.9%–27.5% in the numerical cases with a displacement ventilation; (3) although the increase in the SCL for inefficient airflow distributions is little when the fresh-air ratio is small, the grade of cooling source is increased significantly so that 22.9% more energy is needed in the numerical case with a short-circuit ventilation. This study will be beneficial for the design of air-conditioning systems in non-uniform indoor environments with higher energy-saving capacity.

Electrostatic Transparent Air Filter Membranes Composed of Metallized Microfibers for Particulate Removal.

Particulate matter (PM) from ever-increasing industrialization poses a great public health risk. Although fiber-based filters are used effectively to block PM, filters with high packing densities suffer from excessive pressure drops. Electret filters bypass intermediate- or large-sized particles and thus capture only small particles, the motion of which can be influenced by weak electrostatic fields. In this study, we demonstrate the fabrication of metallized fibers that produce intense electric fields, thereby enabling capture of PMs of a variety of sizes produced by burning incense. The filter consisting of these metallized fibers effectively removes moving particles from air. An electricity-driven filter is relatively thin and has a low packing density, making it light, portable, transparent, and inexpensive. The sizes of the pores between the metallized fibers are readily controlled by manipulating the electrospinning and electroplating times. Sufficiently large pores permit efficient airflow and thus increase permeability without risking an excessive pressure drop. The metallized fiber filter is washable and thus reusable. In this study, a PM removal rate of >97% was recorded using a filter designed under optimal conditions.

Efficient air flow control for remote laser beam welding

Efficient air flow control plays a crucial role for the reliability of remote laser beam welding applications. Local air flows are helpful to suppress unfavorable interactions between laser radiation and welding fumes as a result of absorption and/or scattering effects. On the other hand, local and additional global flows have to be applied for emission control to protect optical components and workpieces from contamination and to avoid harmful air pollution of the atmosphere. However, the appropriate design of complex air flow systems under the additional condition of preferably low overall gas consumption is still a challenging task because a high number of decisive factors and a multitude of possible interactions complicate the pure empirical selection and positioning of suitable flow components and the adjustment of the numerous control parameters. This paper presents the results of a combined and complementary approach of experimental and theoretical investigations to meet these challenges. The experimental work was focused on the aspects of interaction mechanisms between the laser beam and the welding fume. Besides the characterization of process emissions, some of the requirements of stable remote processing with maximum penetration depth are revealed. In contrast, the theoretical work describes a general methodology on how to support the optimization of the cabin air flow by means of Computational Fluid Dynamics (CFD) models in combination with Design-of-Experiment (DoE) approaches.

Ion Wind Generator Utilizing Bipolar Discharge in Parallel Pin Geometry

We present a simple and efficient airflow generator utilizing the effect of ion wind by generating simultaneously both the positive and negative ions from two sharp electrodes mounted parallel to each other. The unique bipolar geometrical setup eliminates the effect of space charge by the high recombination rate of oppositely charged ions. The two-electrode arrangement is symmetrical, where the electrode creating charged ions of one polarity also serves as the reference electrode to establish the electric field required for ion creation by the opposite electrode, and vice versa. Unlike the conventional setup, with a single electrode generating ion wind with movement toward the reference electrode, in this configuration the air movement is parallel to the electrodes, and is directed away from the device. The airflow behavior is studied by both experiments and numerical simulation. The ion wind speed has a linear relationship with the square root of the discharge current, U ∝ √I, and its measured values agree well with simulation. The characterization of the discharge current-voltage relationship was derived from mathematical processing in the general form I = b(V - V <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">o</sub> ) <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">n</sup> . The ion wind speed and the current-voltage characteristics depend on the interspace between the electrodes and the electrode geometry. An ion wind speed on the order of ms <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">-1</sup> is created with a microampere discharge current, resulting in a total net charge of only several femtoampere. The proposed configuration is beneficial in minimizing the power consumption of the system, and in enabling air recirculation for airflow control applications, cooling applications, propulsion technology, and micropump design, especially for the applications where neutralized ion wind flow is required.

Transistor Resizing Based Low Power Thermal Aware Adder Design on FPGA

In this work, we are going to search the most thermal and energy efficient technology among 90nm, 65nm, 45nm, 40nm and 38nm technology based FPGA, and also searching the most thermal and energy efficient airflow, and heat sink profile. We are also doing thermal analysis for 273.15K-343.15K temperature. we are getting 31.67%, 75.71%, reduction in leakage power for 250LFM and 58.53%, 75.71% reduction in leakage power for 500LFM when we scale down ambient temperature from 343.15K to 283.15K for 65nm, 28nm technology based FPGA. There is 84.54%, 85.65%, reduction in junction temperature for 250LFM, 84.90%, 85.65%, reduction in junction temperature for 500LFM when we scale down ambient temperature from 343.15K to 283.15K for 65nm, 28nm technology based FPGA. In this work, we are using 90nm Spartan-3E FPGA, 65nm Virtex-5 FPGA, 45nm Spartan-6 FPGA, 40nm Virtex-6 FPGA, and 28nm Artix-7 FPGA. We are taking two different airflow of 250LFM and 500LFM. LFM is a unit of airflow. LFM is linear feet per minute. Adder is our target design.

Experimental Investigations on Effect of Particles Removal in Cleanroom with Non-Unidirectional Airflow

Efficient airflow delivery is key to achieve effective contamination control for a high-performance cleanroom. The influence of airflow organization on effect of particles removal in cleanroom with non-unidirectional airflow was investigated in this paper. A series of experiments were conducted on a cleanroom experimental platform with different airflow organization modes and supply air volume variation by frequency converter ( 40 to 50 Hz, 5Hz interval) on air-supply fan unit. The results showed that higher cleanliness could be gained at local area in cleanroom with radial airflow organization. Moreover, the outcomes from these experiments indicated that particle concentration at measuring points appeared more orderly when the cleanroom operated with radial airflow organization. The conclusion can be drawn that radial airflow can benefit contamination control at local area for cleanroom operation with non-unidirectional airflow when compared with ceiling-supply and wall-return airflow organization.

Real-Time Implementation of a Constrained MPC for Efficient Airflow Control in a PEM Fuel Cell

<para xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> Fuel cells represent an area of great industrial interest due to the possibility to generate clean energy for stationary and automotive applications. It is clear that the proper performance of these devices is closely related to the kind of control that is used; therefore, a study of improved control alternatives is fully justified. The air-supply control is widely used to guarantee safety and to achieve a high performance. This paper deals with this control loop, proposing and comparing two control objectives aimed at satisfying the oxygen starvation avoidance criterion and the maximum efficiency criterion, respectively. The control architecture is based on a constrained explicit model predictive control (MPC) law suitable for real-time implementation due to its low computational demands. The proposed controller is implemented and evaluated on a 1.2-kW polymer electrolyte membrane or proton exchange membrane fuel-cell test bench, thus obtaining real data which show that the maximum efficiency criterion does not conflict with the starvation avoidance criterion and allows system performance improvements of up to 3.46%. Moreover, experimental results utilizing the explicit MPC approach also show improved transient responses compared to those of the manufacturer's control law. </para>