Roof Vents Research Articles

Odor-Cued Grab Air Sampling for Improved Investigative Odorant Prioritization Assessment of Transient Downwind Environmental Odor Events.

A critical prelude to any community odor assessment should be the prioritization of specific chemical odorants that are most responsible for targeted downwind odors. Unfortunately, and historically, this is a step that has often been bypassed or overlooked. However, correct understanding of the specific impactful volatile organic compounds (VOCs) can inform the follow-on sampling, analytical, and remediation strategies that are most appropriate and efficient, based upon the chemistry behind the issue. With this understanding, the techniques and sampling strategies presented herein should be viewed as a qualitative prelude rather than an addendum to a follow-up routine, automated downwind odor monitoring. Downwind odor characteristics can vary depending upon the size of the upwind source, interim topography, and wind conditions. At one extreme, the downwind odor plume from a relatively large source located on a flat open plain and under stable, near-straight line wind conditions can be rather broad, sustained, and predictable. In contrast, the plume from a small point source (e.g., a roof vent stack) located on irregular topography and under rapidly shifting wind conditions can be intermittent and fleeting ("spikes" or "bursts"). These transient odor events can be surprisingly intense and offensive, despite their fleeting occurrence and perception. This work reports on improving and optimizing an environmental sampling strategy for odorant prioritization from such transient downwind odor conditions. This optimization addresses the challenges of (1) sampling of transient odor "spikes" and (2) prioritizing odors/odorants from multiple, closely colocated point sources under transient event conditions. Prioritizing is defined as identifying the key impactful odorants downwind. Grab air sampling protocol refinement has emerged from actual community environmental odor assessment projects. The challenge of assessing transient odor events has been mitigated by utilizing (a) rapid, odor-cued whole-air grab sampling (i.e., activated by and synchronous with the perceived sensory spikes) into metalized fluorinated ethylene polymer (m-FEP) gas sampling bags; (b) immediate transfer from bags onto solid-phase microextraction (SPME) fibers or sorbent tubes; and (c) maintaining refrigerated storage and shipment conditions between field collection and in-laboratory analysis. Results demonstrated approximately 11-fold increases in target odorant yields for 900 mL air sample capture on sorbent tube transfers from 2 to 3 s "burst" odor event bag captures compared to equivalent direct collections (with sorbent tubes) at the same downwind receptor location but during perceived (stable) odor "lull" periods. An application targeting general odor sampling and point-source differentiation utilizing tracer gases is also presented.

Study on the optimal layout of roof vents and rooftop photovoltaic of the industrial workshop

Roof vents are crucial for facilitating natural ventilation within industrial workshops. However, their substantial size and height can limit available roof space and create extensive shadow areas, thereby impeding the installation of photovoltaic (PV) systems on industrial roofs. This study quantitatively assesses the influence of roof vent positioning, morphology, and roof architecture on the natural ventilation efficiency of workshops with varying indoor heat sources. Subsequently, the study evaluates how different vent configurations affect the installable area for rooftop solar panels. Findings suggest that shifting from traditional roof ridge vents directly above a heat source to north-side vents inclined towards the roof can marginally decrease the ventilation flow rate by approximately 5 %, translating to a minor temperature rise of around 0.46 °C within the occupied zone. Nonetheless, the Predicted Mean Vote (PMV) thermal comfort indices remain consistent across scenarios. Notably, adopting north-side vents, either flush with the roof or inclined, can enhance the annual energy yield of the rooftop PV system by 15.49 % and 22.67 %, respectively, under equivalent solar irradiation. Thus, strategic adjustments to vent positioning, form, and roof design can substantially boost the photovoltaic system's power output without compromising the workshop's natural ventilation performance.

Analytical studies on effects of wind on dispersion of hydrogen leaked in a partially open space

ABSTRACT In order to elucidate ventilation and exhaust of hydrogen (H2) leaked in a partially open space (room) practically, the effects of outer wind (forced external flow) on them were studied analytically by using a CFD (computational fluid dynamics) code in the room of experimental ‘Half-size Hallway model (1/2 Hallway model),’ which has a H2 release hole on the bottom, one vent on the roof (Roof vent) and another vent on the side (Door vent): external air flowed in the room from the Door vent and then H2 was discharged outside from the Roof vent. The H2 concentration distribution in the room was divided into two layers at the height of Door vent, with a high concentration layer above it and a low concentration layer below it, forming a stratified interface. When the wind speed blown into the room increased, the combination of the Realizable k-ε turbulence model and the turbulence Schmidt number of 1.0 improved the reproducibility of the analysis results of H2 concentration distribution. The trial analysis suggested that the concern that wind would increase the indoor H2 concentration could be reduced by using the plate with a simple structure in which two plates were crossed on the Roof vent.

The effect of natural ventilation through roof vents following hydrogen leaks in confined spaces

Hydrogen has a high diffusion rate and a wide range of combustion, making it essential to take safety precautions against leakage during storage. We investigate the change in hydrogen concentration in confined spaces due to hydrogen leakage through experimental and numerical methods assuming the worst-case scenario. The vent area consists of 12 %, 24 %, and 36 % of the floor area and is installed in the ceiling of the concrete enclosure. We confirm that the improvement of ventilation performance is insignificant just by increasing the ventilation area above a certain standard during emergency ventilation. Moreover, the improvement of ventilation performance by forced ventilation is more effective as the natural ventilation area is smaller. Still, the effect decreases as the natural ventilation area becomes larger. In conclusion, we confirm that ventilation efficiency is determined by the natural ventilation area rather than forced ventilation.

An Investigation of the Thermal Performance of a Tropical Greenhouse Constructed With an Earth Air Heat Exchanger

Abstract To maintain optimum plant growth temperature (i.e., 25–35 °C), the thermal performance of an earth air tunnel heat exchanger (EATHE)-integrated single-span saw-tooth greenhouse (GH) was assessed in peak summer. With the side and roof vents opened, natural ventilation due to wind and stack effect controlled the air movement and temperature inside the GH. In this configuration, the average temperature inside the GH remained higher than the ambient temperature by 1.5 °C for the entire period of the experiment. For EATHE (installed at a depth of 3.2 m) assisted GH with polyethylene (PE) cover, the air from the EATHE outlet entered inside the GH at 33 °C, and the average temperature within the GH was maintained at 4 °C lower than the ambient temperature. When the shading net was installed over the PE cover with the EATHE, the transmitted radiations into the GH were reduced from the roof, and the inside temperature was maintained 7 °C below the average ambient temperature (i.e., 45 °C). The measured temperatures along the length of the EATHE were compared with the indigenously developed code named PEAT (performance analysis of earth–air tunnel) and found to be in good agreement within ±4.5% deviation. The temperature distribution inside the GH was predicted using a computational fluid dynamics (CFD) model in ansys fluent with ±5% deviation from experimental results. With parametric analysis from the PEAT code and CFD model, the desired depth of the EATHE and the mass flowrate of air required to bring down the GH indoor temperatures to the optimum plant growth range were determined.

Computational analysis of the hydrogen dispersion in semi-confined spaces

Although green hydrogen is an appropriate clean energy alternative, hydrogen leakage and dispersion are the challenges to establishing safe and reliable hydrogen infrastructure. Released hydrogen in confined or semi-confined space may build up flammable gas clouds, which can have severe consequences for the safety of human life and property. Proper ventilation systems will help in reducing hydrogen gas accumulation. This study presents a comprehensive study to analyse hydrogen dispersion behaviour and the influence of ventilation variations on hydrogen volumetric concentration and stratification. A computational model is developed for the leakage diffusion of hydrogen in an enclosed cuboid space with roof and door ventilation. A detailed analysis is conducted to shed light on the impact of door and roof ventilation positions on forming the flammable cloud. It is observed that the displacement flow and multi-layer stratification are established in the absence of wind or imperceptible air circulation. Single-vent configurations were ineffective, when installed at the top of the leakage point, but multiple-vent arrangements incorporating door and roof vents were found to be more efficient in extracting hydrogen. However, it should be noted that not all multiple-vent arrangements may meet safety requirements. The result indicated that the optimal arrangement for minimizing the size of a flammable cloud involves placing the door vent close to the ceiling while situating the roof vent near the source of leakage. These findings will aid in devising strategies for minimizing the occurrence of flammable cloud formation and preventing hydrogen fire and explosion incidents within partially enclosed facilities.

Design Methodologies for Sizing of Drainage Stacks and Vent Lines in High-Rise Buildings

Diameters for drainage stacks and vent lines within high-rise building drainage systems are determined by consulting building standard agencies’ design codes. While these are critical design decisions, codes are based upon dated research (1940s to 1970s), which has numerous inherent limitations, and the methodologies employed within the codes are unclear. Thus, a new methodology is presented which is based upon an analogy with other forms of multiphase flow transport systems. This methodology assumes, as a pre-condition, that flows of air and the flow of water within the stack are reasonably steady over time. Component diameters must then be chosen which ensure an acceptably large air supply or air–water flow ratio, and an acceptably small pressure excursion within the stack. Two ways to implement this methodology are presented: an ‘explicit approach’, in which component diameters are directly calculated using empirical correlations, and an ‘implicit approach’, in which component diameters are determined by iteration, using a hydraulic model. The methodology pre-conditions of the approach are then discussed. The physical geometry of the stack and branches tends to promote steady water flow but to render air flow very susceptible to temporary interruptions. A need to maintain the air pathway within high-rise drainage systems using components to supplement the air feed drawn in through the roof vent as required is highlighted.

132 Management of horses transported by road in the US on journeys of three hours or less

Horses are regularly transported short distances by road in the US; however, general management practices when traveling less than 3 h are undefined. To investigate, we created an online survey through Qualtrics with questions about the management of an individual horse, plus a few opinion questions about transportation. A subset of 1169 responses from a larger survey were used; each describing a horse who was transported 3 h or less by road between March 2021 to 2022. The most common breeds represented were Quarter Horse (21.2%), Thoroughbred (16.7%) and Warmblood (9.9%). While the majority of horses were adults (60%, ages 5 to 15), 30% were 16 years or older; 58% of horses were geldings and 39% mares. Horses were most often used, and transported, for pleasure or trail riding (44.3%,) followed by showing and competition (31.2%). The majority of horses resided in the Southeast (41.6%) or Midwest (21.2%). A gooseneck (52.2%), slant load (48.4%) trailer with a step-up rear (52.5%) was most commonly used. Ventilation typically consisted of roof vents (71.9%) and side windows (81.9%); rubber mats (86.8%) and shavings or sawdust (61.4%) were the most common flooring and bedding types. Most horses were reported to have been tied (76.6%) at or above eye level (69.2%) during transport. While almost all horses wore halters (95.1%), 26.5% also wore some form of hoof or leg protection when being transported.Within the hour before transport the majority of horses had access to hay or pasture and water (60.2%) and 15.7% received an ulcer preventative or treatment. The majority of horses had access to hay during the transportation (65.6%), and 70.3% had access to hay or pasture and water within the hour following transport. The likelihood of a horse owner taking the temperature, pulse, and/or respiration (TPR) before or after transportation by road increased as the duration of trip increased beyond 3 h; however, 90% reported that they did not take TPR before or after a journey of 3 h or less. When asked various ways to monitor their horse during transport 60% of horse owners said they would be interested in using, or already used, video monitoring and 39% were interested in heart rate monitors. The biggest concern when transporting horses by road was injury to the horse (26.7%), followed by stress (23.1%) and dehydration or overheating (15.6%). The biggest factors when planning to travel were season or weather (24.1%), trip length (21.9%), horse health (16.8%) and traffic (15.5%). The results from the survey show how horse owners are managing horses when transporting by road over short distances in the US

Root Distribution of Tomato Cultivated in Greenhouse under Different Ventilation and Water Conditions.

Mastering root distribution is essential for optimizing the root zone environment and for improving water use efficiency, especially for crops cultivated in greenhouses. Here, we set up two irrigation amount levels based on measurements of the cumulative 20 cm pan evaporation (Ep) (i.e., K0.9: 0.9 Ep; K0.5: 0.5 Ep), and three ventilation modes through opening the greenhouse vents at different locations (TR: open the roof vents only; TRS: open both the roof and south vents; TS: open the south vents only) to reveal the effects of the ventilation mode and irrigation amount on the root distribution of greenhouse tomato. Six treatments were designed in blocks with the ventilation mode as the main treatment and the irrigation amount as the vice treatment. On this basis, the normalized root length density (NRLD) model of six treatments was developed by considering air environment, soil water and temperature conditions, root length density (RLD) and yield. The results showed that air speed of the TRS was significantly higher than TR and TS (p < 0.01), and the air temperature and relative humidity under different ventilation showed the rule: TR > TS > TRS. There was a significant third-order polynomial function relationship between NRLD and soil depth, and the coefficient of the cubic term (R0) had a bivariate quadratic polynomial function relationship with irrigation amount and air speed (determination coefficient, R2 = 0.86). Root mean square errors of the simulated and measured value of NRLD under TR, TRS and TS were 0.20, 0.23 and 0.27 in 2020, and 0.31, 0.23 and 0.28 in 2021, respectively, normalized root mean squared errors were 15%, 17%, 20% in 2020, and 23%, 18% and 21% in 2021. The RLD distribution ratio from the ground surface to a one-quarter relative root depth was 74.1%, and 88.0% from the surface to a one-half relative root depth. The results of the yield showed that a better combination of ventilation and irrigation was recommended as TRS combined with K0.9.

Effects of Vent Size and Wind on Dispersion of Hydrogen Leaked in a Partially Open Space: Studies by Numerical Analysis

To understand the dispersion of hydrogen (H2) leaked in a partially open space practically, which can be considered as a basic model for all processes of transfer, treatment, storage, and disposal of radioactive materials containing fuel debris in the decommissioning of nuclear facilities after a severe accident, this paper uses a computational fluid dynamics code to study analytically the effects of vent size and outer wind on H2 dispersion. The paper adopts the experimental Hallway model, which has a H2 release hole on the ceiling, one vent on the roof (Roof vent), and one vent on the side (Door vent). Air flows in the model (room) from the Door vent while H2 is discharged outside from the Roof vent. The discharged (outflow) amount of H2 increases in conjunction with the air inflow when the size of the Roof and/or Door vents is increased, and then vice versa. The effect of wind depends on the direction to the Door vent: Wind from the same direction as the Door vent promotes H2 discharge while wind from the opposite direction suppresses it. The dispersion behavior characteristics of indoor leaked H2 are clarified for comparing model tests with the same Froude number and different scales. It is found from the analysis results of comparing model tests with the same Froude number and different scales that when H2 leaks into the room and diffuses to the air, the flow generated by the buoyancy of mixed gas creates the stack effect, which causes natural ventilation by drawing in air from the outside through the vent. In addition, it is speculated that the H2 concentration decreases after its leak by quickly mixing with air that flows in from the vents and reaches the floor due to the Coanda effect, which is the effect of the free jet being drawn to a nearby wall.

Sizing of pressure aeration systems for stored grain

Aeration is widely used to cool grain, preserving the physical conditions of the stored product and appearing as one of the most important practices of the postharvest sector in terms of food security. The proper sizing of the aeration system components is essential for guaranteeing the correct operation and management of this preventive technique. Either pressure or suction airflow could be used in most grain storage structures, with pressure systems being most popular. In this article, procedures required when sizing pressure aeration systems for stored grain are discussed. The main equations and recommendations for selecting the proper fan power and size are presented, aiming at allowing to deliver the adequate aeration airflow rate for grain storage during aeration. Technical information about how to calculate the dimensions of roof vents are also showed, in order to provide natural ventilation inside the storage and avoid under-roof condensation. Additionally, a methodology for calculating the dimensions of the aeration perforated ducts is proposed, aiming at suitable uniformity of airflow in the grain mass during this process. Technical and scientific information described in the literature were integrated with empirical rules and recommendations, resulting in a guideline capable of helping students and engineers that need to size pressure grain aeration systems for flat and cylindrical bins.

Numerical Analysis of Ventilation Efficiency of a Korean Venlo-Type Greenhouse with Continuous Roof Vents

A Venlo-type greenhouse with a continuous roof vent (CR-Venlo greenhouse) was proposed by the Ministry of Agriculture, Food and Rural Affairs, South Korea (2019) for natural ventilation even during summers. It is ventilated through the buoyancy effect of the heated air using the high eave elevation. However, the CR-Venlo greenhouse was not distributed domestically, and its ventilation efficiency was not quantitatively evaluated. We aimed to analyze the natural ventilation efficiency of the greenhouse according to the eave height, using computational-fluid-dynamics. The simulation model was analyzed for hot summer conditions. The target greenhouse is ventilated only through the roof vent with all roof windows open; therefore, the air introduced through the roof window is easily exhausted. To evaluate the efficiency of ventilation, the external air entering through the roof window was calculated and evaluated. The amount of incoming air varied greatly with the location of the span and average temperature of the greenhouse; The temperature of the crop zone decreased lognormally with increasing height of the eave. Moreover, the ventilation efficiency of CR-Venlo greenhouse could be increased by improving the ventilation structure such as a shape, position or combination of roof window.

Ventilation and irrigation management strategy for tomato cultivated in greenhouses

Appropriate ventilation and water management strategy are beneficial to boost crop yield and quality in greenhouses, and their optimization is crucial for improving water use efficiency (WUE). Here, we set up three irrigation levels based on measurements of the cumulative pan evaporation (AEpan) (i.e. 0.9 AEpan, 0.7 AEpan, and 0.5 AEpan), and three ventilation modes through opening the greenhouse vents at different location (VST: open the both roof and south vents; VT: open the roof vents only; VS: open the south vents only) to reveal the effects of ventilation mode and irrigation amount on picking, yield (Y), evapotranspiration (ET), WUE and quality of tomato grown in a solar greenhouse. Nine treatments were split block design with ventilation mode as main treatment and irrigation amount as vice treatment. Each treatment was replicated three times. Results showed that harvesting time of tomato were substantially influenced by ventilation mode as a result of interior temperature differences. The VT treatment was beneficial to early maturity of tomato than the VST and VS treatments. The proportion of VT in the first three harvesting was ~36.8 % and ~26.3 % higher than of VST and VS, respectively. Irrigation amount had a marked effect on ET, Y, WUE, irrigation water use efficient (IWUE), and irrigation water compensation (Irc). Here, ET, Y and Irc of K0.9 were 51.7 % and 69.8 %, 11.0 % and 19.6 %, 7.0 % and 13.5 % higher than those of K0.7 and K0.5 treatments, respectively, while the WUE and IWUE were 13.1 % and 24.8 %, 18.6 % and 28.6 % lower than K0.7 and K0.5, respectively. However, the significant interaction between ventilation and irrigation were only found on Y, WUE and IWUE. Both ventilation and irrigation treatments had considerable effect on soluble solids (TSS), Vc and organic acid. TSS could represent the comprehensive quality of tomato, because TSS was very significantly positively correlated with the comprehensive quality scores. A better combination of ventilation and irrigation was recommended as VST × 0.7 AEpan by using the TOPSIS method based on a compromise of Y, quality and WUE.

Using Computational Fluid Dynamics to Evaluate High Tunnel Roof Vent Designs

Freestanding high tunnels are cost-effective, plastic film-covered growing structures that use very little to no modern environmental control technology. Natural ventilation is used to control temperature and humidity. Typically, ventilation openings are created along the sides by manually rolling up a section of the plastic film cover. While common on greenhouses, roof vents are not typically part of high tunnel designs used in the United States. This paper focuses on high tunnel ventilation during the summer, when maximizing the air exchange rate results in a low differential between inside and outside air temperatures. Computational fluid dynamics (CFD) simulations were used to evaluate the effects of several roof vent designs on the air flow rate through the high tunnel and the inside air temperature. The CFD models were developed and validated using environmental data collected at the Pennsylvania State University High Tunnel Research and Education Facility (Rock Springs, PA, USA). Five ventilation designs were simulated using a commercial CFD software package that was augmented with a radiation and crop architecture model. A root mean square error of 0.87 °C was found between the measured and simulated high tunnel temperatures (n = 144). The designs with roof vents were found to increase mass-based ventilation rates through the high tunnel by 20% to 78%. However, they did not lower inside air temperature more than 0.1 °C compared to the traditional design with roll-up side vents only. Additional research is needed to evaluate whether the control of other environmental parameters and weather conditions warrants the use of high tunnel roof vents, especially for humidity control and the combination of high temperature with low wind speed conditions.

Air pollutant dispersion around high-rise buildings due to roof emissions

Air quality in the built environment has a significant impact on public health, particularly in densely populated cities where residents live in closely-packed high-rise buildings. In this case, communicable respiratory diseases are apt to spread through vent pipe emissions on the building roof and facilitate community transmission. This study applied computational fluid dynamics to simulate the dispersion of the pollutants discharged from the roof vent pipes around high-rise buildings. The results show that the dispersion process is dominated by wind-structure interaction, wind incidence angle, air pollutant discharge location, and vent pipe height, and the dispersion is more complex around crucifix-form buildings than cubic ones. When the wind incidence angle reaches around 90°, the air pollutants are entrained in the re-entry of the building, thus impeding the dispersion process. The building areas most adversely affected by air pollutants are located on high floors near the vent pipe. Changing air pollutant discharge location and increasing the height of the vent pipe can significantly reduce the affected area. Where the height of the vent pipe is restricted, parapets at the roof edges are suggested to further reduce the adverse effects of air pollutants. These research findings can help to reduce the risk of airborne contaminants/diseases spreading in current and future built environments.

Emission of airborne microplastics from municipal solid waste transfer stations in downtown

With the continuous progress of urbanization, municipal solid waste (MSW) transfer stations, which are key points for garbage collection and transportation, have moved to residential areas than before. The emission characteristics of gas-phase emerging contaminants should be comprehensively assessed in the assessment of health threats to workers and environmental risks. In this study, the emission characteristics of airborne microplastic particles (>50 μm) were analyzed on the roof vent and waste reception hall of four MSW transfer stations in Shanghai during different seasons. The average concentration of airborne microplastic particles was 2.5 ± 1.3 n/m3. The particle sizes of airborne microplastics at the four waste transfer stations were mainly in the range of 100 μm to 500 μm. Microplastics mainly occur as films and fibers. The dominant microplastic type was Rayon, which accounted for 69.4% of the total amount. The rate of microplastic particles emission into the environment for a single transfer station was estimated to be in the range of 41,297 to 82,593 n/h. Compared with the waste reception hall, the concentration of airborne microplastic particles in the roof vent decreased by 25%, which indicated that the odor treatment facility effectively reduces the concentration of microplastic particles.

Spread of SARS-CoV-2 aerosols via two connected drainage stacks in a high-rise housing outbreak of COVID-19

Vertical transmission of severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) along a vertical column of flats has been documented in several outbreaks of coronavirus disease 2019 (COVID-19) in Guangdong and Hong Kong. We describe an outbreak in Luk Chuen House, involving two vertical columns of flats associated with an unusually connected two-stack drainage system, in which nine individuals from seven households were infected. The index case resided in Flat 812 (8th floor, Unit 12), two flats (813, 817) on its opposite side reported one case each (i.e., a horizontal sub-cluster). All other flats with infected residents were vertically associated, forming a vertical sub-cluster. We injected tracer gas (SF6) into drainage stacks via toilet or balcony of Flat 812, monitored gas concentrations in roof vent, toilet, façade, and living room in four of the seven flats with infected residents and four flats with no infected residents. The measured gas concentration distributions agreed with the observed distribution of affected flats. Aerosols leaking into drainage stacks may generate the vertical sub-cluster, whereas airflow across the corridor probably caused the horizontal sub-cluster. Sequencing and phylogenetic analyses also revealed a common point-source. The findings provided additional evidence of probable roles of drainage systems in SARS-CoV-2 transmission.

The influence of incubator design features on the incubation result

This article shows the results of chicken eggs incubation by IUP-F-45 and BioStreamer 165HD. There were two different types of machines during two-lots of eggs incubation. The BioStreamer 165HD is equipped with such feature as flexible incubation environment tuning according to its technology of embryo feedback. The sensors control the temperature inside machine by using the temperature of egg shells. Also there are sensors which can monitor the humidity level by controlling and predicting the humidity loss of each egg lot and using the narrow-hatching window technology. The incubators are managed by controller and connected to one computer network. The eggs are set to cellular structure incubation tray. The pulsators are equipped with five wide blades to ensure the required air flow rate. In addition, the roof vents have been improved. The power of the heating elements has been increased, which provides a quick heating time for all eggs at the beginning of the incubation cycle. The larger diameter of the cooling coil creates a wider overall cooling surface. As a result of the research, it was found that the use of the BioStreamer incubator made it possible to increase the hatchability of eggs, to carry out the simultaneous hatching of young brood, reducing the hatching by 5.5 hours, to increase the yield of conditioned young chickens by 0.9% and its quality, to obtain a greater amount of meat products from broilers: the average weight of chickens increased by 2.7 per cent, the safety of brood - by 3.6 per cent.

Prediction of effective ventilation in a bleaching industry using CFD analysis – A case study

Numerous industrial challenges revolve around optimization, which necessitates the use of appropriate methodologies for determining the optimal solution. This article discusses the primary issues that arise while performing CFD analysis. However, it is noted that the classical optimization strategies described in the literature may be inapplicable in real-world circumstances when the problem is highly complex. In this research, computational fluid dynamics (CFD) was used to optimise the level of velocity and temperature distribution within the industry that humans can endure throughout the textile steaming process. A detailed evaluation of all methods is conducted across a variety of scenarios using a variety of performance metrics in order to identify alternate approaches to resolving such issues. This is utilised for thermal management studies in the industrial sector. An investigation was carried out for a bleaching industry. Five different cases were considered to study the thermal behaviour. Among all the cases, if roof vents are open workers feel very comfortable. Because the temperature and velocity patters give superior results when compared to all the cases. Suggestions were given to the industry to incorporate this optimization process into an efficient bleaching process.

Experimental Investigation and Numerical Simulation of Air Circulation in a Non-AC Bus Coach System

Air circulation plays a vital role in the comfort of passengers in a bus, being a non-AC bus without any aid from the air conditioning system. The circulation of air is utterly dependent on the design of the bus and the natural flow of air. However, optimize the flow of air inside the bus, a study on the design of the bus is needed. In this regard, experimental work was carried out to achieve uniform airflow by redesigning the coach into an aerodynamic shape. The openings are provided at the leading edge of the bus to evaluate the best possibility for air to circulate in the bus. Three openings were provided at the leading edge of the bus, the first and second openings were mere openings, and the third opening was fitted with a roof vent providing three different geometric patterns to airflow. The initial boundary conditions were developed by considering that all windows and doors of the bus are closed. The scaling ratio of 1:20 was considered for modeling the bus. The experiments were conducted in the wind tunnel test rig. It was observed from the experimentation that the velocity of the air was considered to be the most influential parameter for the optimal air circulation. The velocities of 21.96 m/s and 22.68 m/s were obtained inside bus. The obtained experimental velocities were validated with results obtained by the Computational Fluid Dynamics (CFD). It was observed that a deviation of 5% for the given velocity of 20 m/s.