Air Circulation System Research Articles

Assessment of a LPG hybrid solar dryer assisted with smart air circulation system for drying basil leaves

The fluctuation of solar radiation throughout the day presents a significant obstacle to the widespread adoption of solar dryers for the dehydration of agricultural products, particularly those that are sensitive to high temperatures, such as basil leaf drying during the winter season. Consequently, this recent study sought to address the limitations of solar-powered dryers by implementing a hybrid drying system that harnesses both solar energy and liquid petroleum gas (LPG). Furthermore, an innovative automatic electronic unit was integrated to facilitate the circulation of air between the drying chamber and the ambient environment. Considering the solar radiation status in Egypt, an LPG hybrid solar dryer has been developed to be suitable for both sunny and cloudy weather conditions. This hybrid solar dryer (HSD) uses indirect forced convection and a controlled auxiliary heating system (LPG) to regulate both temperature and relative humidity, resulting in increased drying rates, reduced energy consumption, and the production of high-quality dried products. The HSD was tested and evaluated for drying basil leaves at three different temperatures of50, 55, and 60 °C and three air changing rates of 70, 80, and 90%, during both summer and winter sessions. The obtained results showed that drying basil at a temperature of 60 °C and an air changing rate of 90% led to a decrease in the drying time by about 35.71% and 35.56% in summer and winter, respectively, where summer drying took 135–210 min and winter drying took 145–225 min to reach equilibrium moisture content (MC). Additionally, the effective moisture diffusivity ranged from 5.25 to 9.06 × 10− 9 m2/s, where higher values of effective moisture diffusivity (EMD) were increased with increasing both drying temperatures and air change rates. Furthermore, the activation energy decreased from 16.557 to 25.182 kJ/mol to 1.945–15.366 kJ/mol for the winter and summer sessions, respectively. On the other hand, the analysis of thin-layer kinetic showed that the Modified Midilli II model has a higher coefficient of determination R2, the lowest χ2, and the lowest root mean square error (RMSE) compared to the other models of both winter and summer sessions. Finally, the LPG hybrid solar dryer can be used for drying a wide range of agricultural products, and it is more efficient for drying medicinal plants. This innovative dryer utilizes a combination of LPG and solar energy, making it efficient and environmentally friendly.

A novel solid-phase extraction device for the pneumatic cycle pharmaceuticals residues adsorption: A proof of concept study

In this study, a pneumatic cycle device, herein called the air-operated solid-phase extraction (AO-SPE), was designed for the enrichment of pharmaceutical residues. The device consisted of two parts: an air circulation system and an adsorption system. The continuous air flow ensured that the water sample flowed past the adsorbent, completing the adsorption process. One significant advantage of this device is that the air circulation system can generate pneumatic cycle adsorption with the continuous air flow, increasing the interaction between the adsorbent and the target analytes. Additionally, the entire device is easy to install and dismantle, and the adsorbent can be easily replaced, making the AO-SPE suitable for various types of adsorbents materials tailored to specific target analytes. The smart design is aimed at extracting trace analytes in the large-volume water samples. As a proof-of-concept, the AO-SPE was applied to enrich non-steroidal anti-inflammatory drugs in soil. A Ce-based metal organic framework composite was prepared and applied to verify the applicability of AO-SPE, exhibiting the enrichment factor of up to 538. The results showed that AO-SPE exhibited a maneuverable approach with high efficiency and sensitivity for analyzing large-volume samples, indicating a great potential for extracting of trace analytes.

Risk evaluation of respiratory droplet dispersion in high-speed train compartments with different air circulation systems

Ongoing respiratory epidemics are raising health concerns in public transportation environments, especially in densely populated train compartments. While air circulation systems inside these compartments play a crucial role in controlling the risk of droplets carrying pathogens, the mechanisms and strategies have rarely been investigated. This study employs computational fluid dynamics (CFD) to investigate the impacts on droplet dispersion and exposure risk within passenger compartments under two prevalent air circulation modes: centralized return-centralized exhaust (CR-CE) and distributed return-centralized exhaust (DR-CE), as well as a newly proposed mode, distributed return-distributed exhaust (DR-DE). Additionally, other key influential factors, including the release source location and the respiratory jet speed, are also considered. The results indicate that the CR-CE mode exacerbates the longitudinal airflow in the passenger compartment, thereby increasing the distance of droplet transmission. In contrast, the DR-CE mode moderately restricts the range of droplet spread to a certain extent. When the release source is in the middle of the compartment, the average distance of droplet transmission can be reduced by about 30%. The proposed DR-DE mode further confines the behavior of droplet dispersion, significantly lowering the overall exposure risk for passengers. Furthermore, the results show that sneezing, compared to speaking, results in a decrease in the exposure risk peak among passengers, from approximately 95% to around 70%. The passengers in the four rows directly in front of the release source face a relatively high potential risk. These findings provide valuable insights for improving air quality and passenger safety in public transportation vehicles.

A complete review on enhancing air circulation and filtration for improving internal air quality in a healthy school environment

The health of staff and students is impacted by Indoor Air Quality (IAQ) in educational environments. A healthy atmosphere depends on good IAQ, yet millions of students worldwide might develop respiratory illnesses due to poor air quality. Immediate action is required to alleviate the burden of IAQ consequences in the pandemic-dominated period. This detailed evaluation focuses on techniques for improving air circulation and filtration systems to meet the critical demand for improved IAQ in schools. This research demonstrates the negative impacts of inadequate IAQ on students and educators’ cognitive capacities, health and performance based on an extensive examination of current records. A healthy learning environment, on the other hand, can minimize absenteeism, raise test results and increase pupil/teacher education/teaching productivity. This review explores the effectiveness of different ventilation as well as filtration methods, such as air purifiers, mechanical ventilation, natural ventilation and advanced filtration systems, in lowering airborne pollutants like particulate matter, volatile organic compounds (VOCs) and microbiological contaminants. This study reviews current information, emphasizes recent findings along with options and provides guidelines for the future of education. It underlines the limits of previous studies, gives ideas for further research and indicates a path forward for more enhancements to the air quality in schools. Comprehensive analysis with greater sample numbers is required to evaluate student performance, indoor contentment and environmental health exposure. On-site measurements are essential for comprehending the properties of contaminants. Intricate mitigation strategies must take health impacts, IAQ and energy efficiency into effect.

Effectiveness of Asthma Home Management Manual and Low-Cost Air Filter on Quality of Life Among Asthma Adults: A 3-Arm Randomized Controlled Trial.

Asthma affects the quality of life (QoL) of millions of people worldwide. Effective control is paramount to a decline in prevalence and severity. To address this, we aimed to investigate the effectiveness of an asthma home management manual and low-cost air filter in improving resource-limited settings. This randomized controlled trial was conducted between March to July 2022. The participants were 18-55 years old outpatient with asthmatic patients. A total of 114 participants were recruited and randomly assigned to three groups: home management only, home management and air filtering, and control. Validated measurement tools were applied, and the Wilcoxon test was used to evaluate changes in QoL. Asthma burden was found in at least one-third of participants in each group. At baseline, there was no difference in mAQLQ scores among participants in all group allocations (p-value > 0.05), and the air filter group had an increase in the total mAQLQ score (p-value = 0.044) and post-intervention activity quality of life (p-value = 0.002). The environmental quality of life increased post-intervention (p-value = 0.004) and remained higher after four weeks of follow-up compared to baseline (p-value = 0.041) in the home management group participants. The findings indicate that the enforcement of a home management manual and the application of low-cost filters in air circulation systems offer advantages in improving the quality of life of patients with moderate and mild asthma.

Improved grey principal component analysis neural network based adaptive thermal comfort model: Application in the enclosed cabin with microclimatic conditions

Predicting the thermal comfort of operators in enclosed cabins under extreme operational conditions is crucial for the enhanced and optimal design of cabin air circulation systems. In this study, an improved supervised machine learning algorithm, namely a Grey Principal Component Analysis (G-PCA) was proposed to evaluate the operators’ thermal comfort. The comprehensive dataset was first attained and constructed from the proposed 32 indicators, which recorded each tested object’s EEG and physiological features, core body temperature, skin temperature, and subjective assessments. The accuracy of the proposed model was demonstrated by comparing it with the results predicted via existing indicator sets (PMV and 7-point skin temperature) and modelling algorithms (BP and PCA BP). The results showed that the prediction accuracy of the PMV model, 7-point skin temperature, the 32 indicators were found to be 79.4%, 82.8%, 96.1%, utilising the G-PCA WNN algorithm, and the prediction accuracy of BP, PCA BP, G-PCA WNN is 82.3%, 89.9%, 96.1%, based on the 32 indicators. A conclusion could be drawn that the proposed 32 indicators can incorporate a more comprehensive range of thermal comfort information, and the improved G-PCA WNN thermal comfort prediction model achieved the best prediction performance among the compared algorithms and models.

Performance of greenhouse effect-hybrid type tray dryer in drying cloves

The open sun drying method needs to be improved. This study aimed to evaluate the performance of the greenhouse effect hybrid (GHE-hybrid) type tray dryer using solar and biomass energy in drying cloves as a sustainable dryer for future. The dryer has 10 series of thin layers at gap of 10cm and each layer contains of 4 separated trays by 0.80m x 0.75m cross-section. We had run 2 experiments at capacity of 72 and 244kg, respectively. Results showed that increasing the drying capacity will prolong the drying time. The low solar irradiation will also increase the use of biomass energy and the input energy in the system was dominated by biomass energy at level of 75%. The drying temperature ranged from 37 to 46°C. The humidity was relatively high while the air velocity in drying chamber was lower than 0.68m/s and non-uniformly distributed. The moisture of cloves was reduced below 14% in both experiment after 3 and 6 days drying, respectively. The thermal efficiency was about 14 to 15% and the drying efficiency was 17%. The use of GHE-hybrid dryer is promising to be used by farmers sustainably. However, the dryer needs some improvement on air circulation system.

Penerapan Good Handling Practices (GHP) dan Optimalisasi Solar Dryer Tipe Rak untuk Meningkatkan Mutu Biji Kopi Kelompok Tani Karya Makmur Sidomulyo, Kecamatan Air Naningan, Kabupaten Tanggamus

Coffee is one of the strategic plantation commodities that significantly contributes to the economy in Indonesia. The lack of proper post-harvest handling of coffee has resulted in the low quality of coffee beans produced by farmers affiliated with the Karya Makmur Farmer Group. This activity aims to (1) provide technical guidance on proper post-harvest handling of coffee to partner farmers, (2) modify drying racks and air circulation systems to enhance the capacity of the solar dryer dome, and (3) improve the quality of coffee beans produced in accordance with general coffee quality standards. The implementation of the activity has been successful, yielding the following results: 1) There has been an increase in knowledge and skills among members of the Karya Makmur farmer group in post-harvest coffee handling according to Good Handling Practices (GHP), 2) The Outreach Team has constructed one unit of a stacked-rack solar dryer with a drying capacity of 450 kg as an additional drying tool that can be utilized by the group, 3) The performance of the stacked-rack solar dryer produces better quality coffee beans compared to drying using the solar dryer stackted rak or sun-drying on the ground, and 4) The use of the stacked-rack solar dryer is effectively utilized by the Karya Makmur farmer group in the drying process of fresh coffee beans as well as for other commodities.

Innovative technologies combating with dust emission releasing into the atmosphere

An examination of various approaches, methods, and technologies recommended as optimal for safeguarding atmospheric air against dust pollution has led to the identification of the distinct advantages associated with vortex inertial dust collectors utilizing swirling currents. These collectors, referred to as Cyclone Separation Fans (CSF), have been determined to serve as primary and auxiliary equipment in dust removal systems within the production of building materials and other industries. Traditionally employed circuit designs for dust collection systems were also subject to analysis, revealing two prevalent types: open and partially closed air circulation systems. In the latter, a portion of the cleaned airflow is reintroduced into the system, representing a key feature of the design. This assessment underscores the significance of vortex inertial dust collectors, specifically CSFs, as instrumental components in dust removal systems across various industrial sectors. Their effectiveness in mitigating dust pollution, coupled with their versatility as both primary and supplementary equipment, positions them as recommended technologies for atmospheric air protection in the production of building materials and other related industries. The recognition of open and partially closed air circulation systems in traditional dust collection circuit designs further contributes to refining and optimizing dust removal processes for enhanced environmental protection.

Identifikasi dan Evaluasi Pengaruh Ventilasi Alami pada Ruang Kelas Terhadap Fenomena Sick Building Syndrome

Natural ventilation is closely related to the indoor air quality and will affect the occupant activities. The unhealthy air conditioning will create discomfort for the occupants. One of the phenomena that is caused by indoor air quality is Sick Building Syndrome (SBS). Bad air circulation systems in the classroom can lead to Sick Building Syndrome (SBS) among students. This study was conducted to identify and evaluate the influence of natural ventilation in the classroom on the Sick Building Syndrome phenomenon. The object of the study was classrooms in the Department of Architecture, Faculty of Engineering, Diponegoro University. Data of temperature, relative humidity, and air velocity were collected to identify the indoor air quality of the classrooms. Based on the analysis, either with closed or open natural ventilation, the indoor air quality inside the classroom still did not meet the requirement of healthy air. Therefore, further actions such as improving the quality of natural ventilation are needed.

SOCIALIZATION OF THERMAL COMFORT STANDARDS AT SMKN 4 SOUTH TANGERANG

Vocational High School (SMK) is a formal education unit that provides education that prepares students to work in specific fields. Students can continue their vocational education after completing their education at the junior high school level. SMK Negeri 4 South Tangerang is one of the 4th Vocational High Schools in the City of South Tangerang, specializing in Building Modeling and Information Design, Health Services, Animation, and Visual Communication Design. SMKN 4 South Tangerang is located on Jalan Sumatra-Tidore, Jombang Village, Ciputat District, South Tangerang City, Banten Province, with a land area of 4,562 m2. Currently, SMK Negeri 4 South Tangerang uses a natural air circulation system with openings in each class; then, each class uses a fan for artificial air circulation. There are four types of building comfort: thermal comfort, space comfort, and audio comfort. Space comfort is related to the comfort of movement space and relationships between spaces. Meanwhile, thermal comfort is an essential part of building comfort because room temperature influences the feeling of comfort. This is because every human being has sensors on their skin that work when there are hot or cold temperatures. Thermal comfort conditions that comply with standards will help the teaching and learning process be streamlined at SMK Negeri 4 South Tangerang. So that SMK Negeri 4 South Tangerang has thermal comfort that meets standards, Budi Luhur University organizes Community Service activities to socialize the achievement of thermal comfort at SMK Negeri 4 South Tangerang. The method of implementing activities uses the concept of Problem Solving. At the same time, the Problem-Solving concept uses input stages, problem-solving processes, and output. The aim of socializing the achievement of thermal comfort is so that the management of SMK Negeri 4 South Tangerang knows how to achieve thermal comfort standards so that students at the School are comfortable when carrying out the teaching process.

Humidity Control for Air Circulation in the Drying Process

Recycling exhaust air is acknowledged as a method to reduce the energy consumption of agricultural products in the dryer. This study investigates the performance of an air circulation system at a laboratory scale and develops a feedback control compensator for optimizing the drying air circulation process. A servo motor is employed to drive a valve, to feed the exhaust drying air with high temperature and humidity back in different proportions. The system is controlled using an Arduino DUE microcontroller, which communicates data with MATLAB/Simulink. The system identification methodology is employed to analyze the mathematical model of the system. The result indicates that the response of the system meets the acceptance criteria when the percent overshoot is less than 25%, and the settling time is within 60 seconds (with a 2% error tolerance). Evaluation of control system performance during equilibrium employs R2 and RMSE values.

Work-related Skin Disease Symptoms in Tofu Makers in Cipayung District

Introduction: One of the risks that may come from exposure to chemicals, physics, and biological agents in the interaction of processes in industrial activities, particularly in the business of making tofu in the tofu maker's environment, is a work-related skin disease. The number of years of employment, chemical exposure and the time spent each day, hand-washing routines, and the use of personal protective equipment while at work are additional risk factors known to influence the frequency of occupational skin disorders. This study seeks to obtain information about the symptoms and some risk factors of work-related skin diseases in tofu makers in Jalan Raya X, Cipayung District. Methods: The analytical cross-sectional design with a chi-square test was carried out with 50 tofu makers as the total research sample. Measurements were made using the modified Nordic Occupational Skin Questionnaire (NOSQ-2002)/LONG. Results: The study found that 46% (23 people) of tofu makers did experience symptoms of work-related skin diseases. As many as 84% (42 people) of tofu makers with a working period of more than 3 years, and as many as 96% (50 people) had exposure 3 hours per day. As many as 62% (31 people) had bad hand-washing habits, and 96% (48 people) did not fully use personal protective equipment. Conclusion: Improvement of supporting facilities and infrastructures in the production area, such as air circulation systems, modification of machinery and equipment, setting working hours, and providing proper cleaning facilities will increase the health status of workers.

Optimization of the Outlet Shape of an Air Circulation System for Reduction of Indoor Temperature Difference

This study proposes an air circulation system that can forcibly circulate the lowest cold air to the top of indoor smart farms, and it has a width, length, and height of 6, 12, and 2.5 m, respectively, to reduce the effect of temperature differences between the upper and lower parts on the growth rate of plants in winter. This study also aimed to reduce the temperature deviation generated between the upper and lower parts of the target indoor space by optimizing the shape of the manufactured outlet of the air circulation system. A table of L9 orthogonal arrays, which is a design of experiment methodology, was used, and it presented three levels of the following design variables: blade angle, blade number, output height, and flow radius. Flow analysis was performed for the experiments on the nine models to minimize the high time and cost requirements. Based on the derived analysis results, an optimized prototype was manufactured by applying the Taguchi method, and experiments were conducted by installing 54 temperature points in an indoor space to identify the temperature difference between the upper and lower parts over time for the performance experiment. Under natural convection, the minimum temperature deviation was 2.2 °C and the temperature difference between the upper and lower parts did not decrease. For a model without an outlet shape, such as a vertical fan, the minimum temperature deviation was 0.8 °C and at least 530 s were required to reach a difference of less than 2 °C. When air was circulated in the air circulation system with the proposed outlet shape, the minimum temperature deviation was 0.6 °C and the time required to reach a difference of less than 2 °C was 440 s. Using the proposed air circulation system, cooling and heating costs are expected to be reduced in summer and winter because the arrival time and temperature difference between the upper and lower parts can be reduced using the outlet shape compared with the case without the outlet shape.

Numerical investigations on roof ventilator turbine performance characteristics using ANSYS

Rooftop wind turbine ventilators are natural air circulation systems that employ a rotating blade to remove stale air from a building, improving the indoor air quality and saving money in the process. The effectiveness of a roof ventilator turbine depends heavily on its construction. By varying the diameter of the turbine blades (500, 670, and 690 mm), this CFD study modeled and examined three distinct designs for wind-driven ventilation devices. This numerical analysis was further developed to compute the presentation of a rotating ventilator by analyzing the pressure, turbulence kinetic energy, and velocity of the airflow related with the ventilator at variant designs. To investigate the viability of a numerical approach to modeling the many aspects of a ventilator flow, a computational fluid dynamics (CFD) analysis was conducted utilizing the conventional k- turbulence model with the multiple reference frame meshing method. The proposed design of a 690 mm ventilator blade for a rooftop turbine was found to perform better than two alternative designs using computational fluid dynamics (500 and 670 mm turbine blade diameter). The trend lines appear to be in virtuous contract with formerly available data, signifying that mathematical modelling could be a useful and cost-efficient tool for the design, growth, and performance evaluation of a wind-driven rotational ventilation system in the future.

A new system to prevent SARS-CoV-2 and microorganism air transmission through the air circulation system of endoscopes.

Background and study aims Evidence for the modes of transmission of SARS-CoV-2 remains controversial. Recently, the potential for airborne spread of SARS-CoV-2 has been stressed. Air circulation in gastrointestinal light source boxes and endoscopes could be implicated in airborne transmission of microorganisms. Methods The ENDOBOX SC is a 600 × 600 mm cube designed to contain any type of machine used during gastrointestinal endoscopy. It allows for a 100-mm space between a machine and the walls of the ENDOBOX SC. To use the ENDOBOX SC, it is connected to the medical air system and it provides positive flow from the box to the endoscopy room. The ENDOBOX SC uses medical air to inflate the digestive tract and to decrease the temperature induced by the microprocessors or by the lamp. ENDOBOX SC has been investigated in different environments. Results An endoscopic procedure performed without ventilation was interrupted after 40 minutes to prevent computer damage. During the first 30 minutes, the temperature increased from 18 °C to 31 °C with a LED system. The procedure with fans identified variations in temperature inside the ENDOBOX SC from 21 to 26 °C (± 5 °C) 1 hour after the start of the procedure. The temperature was stable for the next 3 hours. Conclusions ENDOBOX SC prevents the increase in temperature induced by lamps and processors, allows access to all necessary connections into the endoscopic columns, and creates a sterile and positive pressure volume, which prevents potential contamination from microorganisms.

Study on Performance of Closed Air Circulation System Driven by Electric Compressor

Study on Performance of Closed Air Circulation System Driven by Electric Compressor

Simulation model and fault analysis of air circulation system of the aircraft based on grasshopper optimization algorithm: support vector machine

Simulation model and fault analysis of air circulation system of the aircraft based on grasshopper optimization algorithm: support vector machine

Risco Químico associado ao setor dos Transportes de Passageiros e Mercadorias

Introduction/framework/objectives Drivers are subject to numerous occupational hazards; however, the associates at the Chemical level are not particularly developed, nor is bibliography on the subject easily found. The aim of this review was to summarize what is most relevant described, in order to enhance the work developed by the Occupational Health and Safety teams with clientes on this sector. Methodology This is a Bibliographic Review, initiated through a search carried out in February 2022, in the databases “CINALH plus with full text, Medline with full text, Database of Abstracts of Reviews of Effects, Cochrane Central Register of Controlled Trials, Cochrane Database of Systematic Reviews, Cochrane Methodology Register, Nursing and Allied Health Collection: comprehensive, MedicLatina and RCAAP”. Contents Individuals with jobs in this sector are exposed to chemical agents resulting from incomplete combustion, engine emissions and elements secondary to the evaporation of fuels. Although some exist in low concentrations, they have carcinogenic potential. After the decrease in lead in gasoline, other substances began to be used more, such as benzene, toluene and xylene; as well as ethanol and metanol, in order to increase efficiency. The International Agency for Research on Cancer has classified benzene as a human carcinogen. In practice, a decrease in the number of blood cells is observed (anemia, thrombocytopenia, leukopenia or even leukemia); although the mechanism is not fully understood. Taxi drivers are considered to be sufficiently exposed professionally to present these changes. The concentration of benzene for these is two to three times lower than that found in the vicinity of structures in the oil industry (for example), but still three times higher than the limit recommended by the American Conference of Government Industrial Hygienists. There is also exposure to other hydrocarbons, particulate matter, heavy metals such as lead and volatile organic compounds. Discussion and Conclusions The Chemical Risk associated with passenger and/or goods transport vehicles is relevant and reasonably little studied, although some medical consequences are very relevant. In terms of collective protection measures, only the use of HEPA filters are mentioned in some contexts, as well as having or not having the window open and the air circulation system on; in the context of individual protection measures, none of the consulted articles developed them. It would be relevant for a Health and Safety team with several clients in these sector, to better assess the situation and disseminate their data and conclusions through the publication of article(s), to have more knowledge to work in this area and be able to provide a healthier and safer work environment. Keywords: chemical risk, driver, taxi driver, occupational health and occupational medicine.

DESAIN INTERIOR DAN MINAT KUNJUNG MASYARAKAT DI PERPUSTAKAAN DAERAH KABUPATEN TRENGGALEK

Interest in visiting the public at the Trenggalek regional library is still relatively low. One of the important factors that can increase the interest in visiting and the comfort of the community is interior design. This study aims to determine the role of interior library design in increasing user interest in visiting and knowing the condition of the library based on the elements of interior library design. This study uses a qualitative method with purposive sampling technique as a way of searching for informants. The informants in this study consisted of 3 informants, namely 2 users who had visited the Trenggalek regional library before and before, and 1 librarian. Researchers used data collection techniques in the form of observation, interviews, and documentation. The presentation of the research is done in the form of a narrative text. The results of this study indicate that the interior design of the Trenggalek regional library has a good influence on efforts to increase public interest in visiting. There are several elements that have been implemented well, including layout, color, and lighting. However, there are still unsatisfactory elements, namely air circulation and sound system. This is due to the small number of fans, the absence of air conditioning, and a whispering sound is still heard. The interior design of the Trenggalek regional library is not optimal due to the limited cost of building a library. Meanwhile, several factors in the interest of visiting are service, infrastructure, attractiveness of the place, and security.