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Systematization and generalization of local exhaust devices characteristics - the basis for engineering design techniques of effective industrial ventilation  [cached]
A.G. Sotnikov,A.A. Borovitskiy
Magazine of Civil Engineering , 2012,
Abstract: The modern development of the industry, new technologies and a lot of harmful substances more than 2500 names attracts a lot of attention to industrial ventilation systems. The subject of this paper is analysis and generalization of foreign experience within the limits of proposed theory. In this paper, as a continuation of the previous papers the basics of designing effective industrial ventilation systems by optimizing air flow were described.An integrated exponential power dependence for defining the recovery effectiveness of different harmful substances by different local exhaust devices was proposed. The conception of equivalent effective velocity was proposed and substantiated.The method of optimal air exchange calculation and engineering design techniques were proposed.
Physical features of small disperse coal dust fraction transportation and structurization processes in iodine air filters of absorption type in ventilation systems at nuclear power plants  [PDF]
Oleg P. Ledenyov,Ivan M. Neklyudov,P. Ya. Poltinin,L. I. Fedorova
Physics , 2012,
Abstract: The research on the physical features of transportation and structurization processes by the air-dust aerosol in the granular filtering medium with the cylindrical coal adsorbent granules in an air filter of the adsorption type in the heating ventilation and cooling (HVAC) system at the nuclear power plant is completed. The physical origins of the coal dust masses distribution along the absorber with the granular filtering medium with the cylindrical coal granules during the air-dust aerosol intake process in the near the surface layer of absorber are researched. The quantitative technical characteristics of air filtering elements, which have to be considered during the optimization of air filters designs for the application in the ventilation systems at the nuclear power plants, are obtained.
Exploring Ventilation Efficiency in Poultry Buildings: The Validation of Computational Fluid Dynamics (CFD) in a Cross-Mechanically Ventilated Broiler Farm  [PDF]
Eliseo Bustamante,Fernando-Juan García-Diego,Salvador Calvet,Fernando Estellés,Pedro Beltrán,Antonio Hospitaler,Antonio G. Torres
Energies , 2013, DOI: 10.3390/en6052605
Abstract: Broiler production in modern poultry farms commonly uses mechanical ventilation systems. This mechanical ventilation requires an amount of electric energy and a high level of investment in technology. Nevertheless, broiler production is affected by periodic problems of mortality because of thermal stress, thus being crucial to explore the ventilation efficiency. In this article, we analyze a cross-mechanical ventilation system focusing on air velocity distribution. In this way, two methodologies were used to explore indoor environment in livestock buildings: Computational Fluid Dynamics (CFD) simulations and direct measurements for verification and validation (V&V) of CFD. In this study, a validation model using a Generalized Linear Model (GLM) was conducted to compare these methodologies. The results showed that both methodologies were similar in results: the average of air velocities values were 0.60 ± 0.56 m s ?1 for CFD and 0.64 ± 0.54 m s ?1 for direct measurements. In conclusion, the air velocity was not affected by the methodology (CFD or direct measurements), and the CFD simulations were therefore validated to analyze indoor environment of poultry farms and its operations. A better knowledge of the indoor environment may contribute to reduce the demand of electric energy, increasing benefits and improving the thermal comfort of broilers.
Sharma Chandan,Rana AC,Bala Rajni,Seth Nimrata
International Research Journal of Pharmacy , 2013,
Abstract: Quality is the primordial intention to any industry and its products manufactured. Recently validation has become one of the pharmaceutical industries’ most recognized and discussed subjects. Validation is the means of catering enormous benefits to even more than the acceptable quality level which in the global standard scale lending importance to validation is increasingly profound in recent years. The word validation simply means “Assessment of validation or action of proving effectiveness”. The process is developed in such a way that the required parameters are achieved and it ensures that the output of the process will consistently meet the required parameters during routine production, the process is validated. Validation and quality assurance will go hand in hand, ensuring the through quality for the products. Hence, an emphasis is made in this review that gives a detailed, overview of validation concept of designing, organizing and conducting validation trials.
Numerical simulation and analysis for indoor air quality in different ventilation  [PDF]
Yang Li
Health (Health) , 2012, DOI: 10.4236/health.2012.412197
Abstract: Indoor air environment includes indoor thermal environment and air quality, and a reasonable ventilation provides guarantee for a good indoor environment. A numerical study of the indoor environment in different ventilation is presented in this paper. The External Energy Saving Lab of the WenYuan Building was selected for this purpose, and its indoor air quality and thermal performance in the typical summer climate were simulated. For the numerical simulation, the techniques of Fluent Air-pak was adopted to establish the physical and numerical model of lab. A attention is given to the velocity field and the distribution of pollutant concentration, followed by a discussion of two ventilation modes (displacement ventilation and up-in and up-out ventilation). By comparison, it is found that the Displacement ventilation in improving indoor air quality is obviously superior to the traditional up-in and up-out ventilation.
Influence of different systems of minimum ventilation on air quality in broiler houses
Menegali, Irene;Tin?co, Ilda F. F.;Zolnier, Sérgio;Carvalho, Cinara da C. S.;Guimar?es, Maria C. de C;
Engenharia Agrícola , 2012, DOI: 10.1590/S0100-69162012000600003
Abstract: to maintain a competitive development of the brazilian aviculture, some measures must be taken to enable the identification and reduction of risks to the health of birds, as well as for the physical environment. therefore, the aim of this study was to evaluate the effectiveness of three different systems of minimum ventilation (positive pressure - svmp, negative pressure - svmn and natural ventilation - svmnat) in the air quality during the first 21 days of life of broiler chicks, during winter. three points were selected along the length to verify ammonia, carbon monoxide and oxygen concentrations at 3a.m., 9a.m., 3p.m. and 9p.m., by the respiration level of birds and workers. the averages of pollutant gases did not exceed the tolerance levels for the three minimum ventilation systems evaluated, which is 20 and 10ppm for the birds level and 20 and 39ppm for the workers level, for ammonia and carbon monoxide, respectively. it was evident that the minimum ventilation systems were appropriately sized for the required minimum ambient air renovation, in respect to ventilation rates applied for the svmn and svmp systems, and with air velocity at levels that do not stress the chicks, including for the svmnat. the three studied systems of minimum ventilation allowed the birds to externalize their productive performance, with values close to the ones considered satisfactory for all evaluated parameters, in accordance with the brazilian aviculture standards.
Enhancement of the greenhouse air ventilation rate under climate conditions of central Mexico
Romero-Gómez, Pedro;Choi, Christopher Y.;Lopez-Cruz, Irineo L.;
Agrociencia , 2010,
Abstract: mexican plastic-covered greenhouses use natural ventilation as the main method to control temperature and humidity. however, no studies on the dynamic behavior of airflow and ventilation rates are available. in the present study, air exchange rates were analyzed in a naturally-ventilated greenhouse in mexico using computational fluid dynamics (cfd). to enhance greenhouse cooling, roof vent areas and screen characteristics were examined undef various scenarios to quantify ventilation rates. the air exchange rates through the tight insect screen (model s) were about 50 % of those achieved with actual and loose insect screen (model sf) at the same outside wind speed. enlargement of the roof vent size ftom 6 % (current) to 15 % of the greenhouse-floor area increased the ventilation rate by 20-40 % at wind speeds ranging from 0 to 4 m s-1. however, extensions of insect-proof screens area on side-walls did not produce any significant change in the ventilation rate. greenhouse orientation was also considered to maximize cooling effects under the local climate condition, and the ventilation rate could be enhanced by positioning the roof vent area in a prescribed direction based on the average wind speed.
The influence of air duct geometry on air jet direction in aircraft cabin ventilated by mixing ventilation.  [cached]
Fi?er J.,Jícha M.
EPJ Web of Conferences , 2013, DOI: 10.1051/epjconf/20134501102
Abstract: The paper deals with instigation of influence of air duct geometry on air jet direction in aircraft cabin ventilated by mixing ventilation. CFD approach was used for investigation and model geometry was based on small aircraft cabin mock-up geometry. Model was also equipped by nine seats and five manikins that represent passengers. The air jet direction was observed for selected ambient environment parameters and several types of air duct geometry and influence of main air duct geometry on jets direction is discussed. The model was created in StarCCM+ ver. 6.04.014 software and polyhedral mesh was used.
Multiple model approach and experimental validation of a residential air-to-air heat pump  [PDF]
Fran?ois Garde,Harry Boyer,Florence Pignolet,Franck Lucas,Jean Brau
Computer Science , 2012,
Abstract: The beginning of this work is the achievement of a design tool, which is a multiple model software called " CODYRUN ", suitable for professionnals and usable by researchers. The original aspect of this software is that the designer has at his disposal a wide panel of choices between different heat transfer models More precisely, it consists in a multizone software integrating both natural ventilation and moisture tranfers . This software is developed on PC micro computer and gets advantage of the Microsoft WINDOWS front-end. Most of time, HVAC systems and specially domestic air conditioners, are taken into account in a very simplified way, or in a elaborated one. On one side,they are just supposed to supply the demand of cooling loads with an ideal control loop (no delay between the sollicitations and the time response of the system), The available outputs are initially the hourly cooling and heating consumptions without integrating the real caracteristics of the HVAC system This paper is also following the same multiple model approach than for the building modelling by defining different modelling levels for the air conditionning systems, from a very simplified one to a detailled one. An experimental validation is achieved in order to compare the sensitivity of each defined model and to point out the interaction between the thermal behaviour of the envelop and the electrical system consumption. For validation purposes, we will describe the data acquisition system. and the used real size test cell located in the University of Reunion island, Indian Ocean.
Cerebral Arterial Air Embolism Associated with Mechanical Ventilation and Deep Tracheal Aspiration  [PDF]
S. Gursoy,C. Duger,K. Kaygusuz,I. Ozdemir Kol,B. Gurelik,C. Mimaroglu
Case Reports in Pulmonology , 2012, DOI: 10.1155/2012/416360
Abstract: Arterial air embolism associated with pulmonary barotrauma has been considered a rare but a well-known complication of mechanical ventilation. A 65-year-old man, who had subarachnoid hemorrhage with Glasgow coma scale of 8, was admitted to intensive care unit and ventilated with the help of mechanical ventilator. Due to the excessive secretions, deep tracheal aspirations were made frequently. GCS decreased from 8–10 to 4-5, and the patient was reevaluated with cranial CT scan. In CT scan, air embolism was detected in the cerebral arteries. The patient deteriorated and spontaneous respiratory activity lost just after the CT investigation. Thirty minutes later cardiac arrest appeared. Despite the resuscitation, the patient died. We suggest that pneumonia and frequent tracheal aspirations are predisposing factors for cerebral vascular air embolism. 1. Introduction Embolism of air into the cerebral vessels is an iatrogenic complication of numerous invasive medical procedures performed in anesthesia and intensive care [1] and may occur either in artery or in vein if an entry in the arterial or venous circulation is created [2–6]. Arterial air embolism associated with pulmonary barotrauma has been considered a rare, but a well-known complication of mechanical ventilation [7]. The volume of intravascular air embolised in the cases is usually small. Massive air embolism to the major cerebral vessels is extremely rare. We report a patient with an unusual air collection at the cerebrum during positive pressure ventilation. 2. Case A 65-year-old man known with long-lasting arterial hypertension arrived at the emergency department in a subcomatose state. Subarachnoid hemorrhage (SAH) was seen on CT scan of brain. When admitting to intensive care unit, Glasgow coma scale (GCS) of the patient was 8 and he had spontaneous but insufficient breathing. Thus he required intubation after 1 hour of ICU admission. The patient was ventilated by mechanical ventilator in spontaneous mode. Four days after intubation the patient had excessive bronchial secretions and nosocomial pneumonia was diagnosed. Due to the excessive secretions, deep tracheal aspirations were made frequently. GCS was 8–10, and he was breathing in spontaneous mode in mechanical ventilator. GCS decreased from 8–10 to 4-5, and the patient was reevaluated with cranial CT scan in the 8th day of admittance. In CT scan, air embolism was detected in the cerebral arteries (Figures 1 and 2). The patient deteriorated and lost spontaneous respiratory activity just after the CT investigation. The airway pressure
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