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Ventilation System (ventilation + system)
Selected AbstractsMultidisciplinary investigations at Stalag Luft III allied prisoner-of-war camp: The site of the 1944 "great escape," Zagan, Western PolandGEOARCHAEOLOGY: AN INTERNATIONAL JOURNAL, Issue 7 2007J.K. Pringle Stalag Luft III, situated in Zagan, Poland (formerly eastern Germany), was the site of a World War II Allied aviator prisoner of war (POW) camp famous for repeat escape attempts,notably the mass escape of 76 POWs in March 1944, shown in the 1963 film "The Great Escape." The site has had little attention to date because it was within restricted military training grounds until 1992. This paper reports on attempts to locate the undiscovered "Dick" escape tunnel (the "Tom" and "Harry" tunnels from the same escape attempt were discovered and destroyed by camp authorities). Geological and geophysical surveys located hut 122, which contained the "Dick" entrance shaft. Subsequent archaeological investigations included surface artifact collection and inspection of the rubble-filled, tunnel entrance shaft. Excavations to a depth of 10 m through yellow glacio-fluvial sand resulted in the discovery of the refilled "Dick" tunnel with intact bed-board shoring and ventilation system. Our investigation provides valuable insights into POW escape efforts. © 2007 Wiley Periodicals, Inc. [source] Some questions on dispersion of human exhaled droplets in ventilation room: answers from numerical investigationINDOOR AIR, Issue 2 2010C. Chen Abstract, This study employs a numerical model to investigate the dispersion characteristics of human exhaled droplets in ventilation rooms. The numerical model is validated by two different experiments prior to the application for the studied cases. Some typical questions on studying dispersion of human exhaled droplets indoors are reviewed and numerical study using the normalized evaporation time and normalized gravitational sedimentation time was performed to obtain the answers. It was found that modeling the transient process from a droplet to a droplet nucleus due to evaporation can be neglected when the normalized evaporation time is <0.051. When the normalized gravitational sedimentation time is <0.005, the influence of ventilation rate could be neglected. However, the influence of ventilation pattern and initial exhaled velocity on the exhaled droplets dispersion is dominant as the airflow decides the droplets dispersion significantly. Besides, the influence of temperature and relative humidity on the dispersion of droplets can be neglected for the droplet with initial diameter <200 ,m; while droplet nuclei size plays an important role only for the droplets with initial diameter within the range of 10 ,m,100 ,m. Practical Implications Dispersion of human exhaled droplets indoor is a key issue when evaluating human exposure to infectious droplets. Results from detailed numerical studies in this study reveal how the evaporation of droplets, ventilation rate, airflow pattern, initial exhaled velocity, and particle component decide the droplet dispersion indoor. The detailed analysis of these main influencing factors on droplet dispersion in ventilation rooms may help to guide (1) the selection of numerical approach, e.g., if the transient process from a droplet to a droplet nucleus due to evaporation should be incorporated to study droplet dispersion, and (2) the selection of ventilation system to minimize the spread of pathogen-laden droplets in an indoor environment. [source] Experimental study of ventilation performance and contaminant distribution of underfloor ventilation systems vs. traditional ceiling-based ventilation systemINDOOR AIR, Issue 5 2004C. Y. Chao First page of article [source] Effect of improved home ventilation on asthma control and house dust mite allergen levelsALLERGY, Issue 11 2009G. R. Wright Background:, The warm, humid environment in modern homes favours the dust mite population, but the effect of improved home ventilation on asthma control has not been established. We tested the hypothesis that a domestic mechanical heat recovery ventilation system (MHRV), in addition to allergen avoidance measures, can improve asthma control by attenuating re-colonization rates. Methods:, We conducted a randomized double-blind placebo-controlled parallel group trial of the installation of MHRV activated in half the homes of 120 adults with asthma, allergic to Dermatophagoides pteronyssinus. All homes had carpets steam cleaned and new bedding and mattress covers at baseline. The primary outcome was morning peak expiratory flow (PEF) at 12 months. Results:, At 12 months, the primary end-point; change in mean morning PEF as compared with baseline, did not differ between the MHRV group and the control group (mean difference 13.5 l/min, 95% CI: ,2.6 to 29.8, P = 0.10). However, a secondary end-point; evening mean PEF, was significantly improved in the MHRV group (mean difference 24.5 l/min, 95% CI: 8.9,40.1, P = 0.002). Indoor relative humidity was reduced in MHRV homes, but there was no difference between the groups in Der p 1 levels, compared with baseline. Conclusions:, The addition of MHRV to house dust mite eradication strategies did not achieve a reduction in mite allergen levels, but did improve evening PEF. [source] High levels of grass pollen inside European dairy farms: a role for the allergy-protective effects of environment?ALLERGY, Issue 7 2009B. Sudre Background:, There is evidence of an allergy protective effect in children raised on farm. It has been assumed that microbial exposure may confer this protection. However in farm, little attention has been given to the pollen level and to concomitant microbiological exposure, and indoor pollen concentrations have never been precisely quantified. Methods:, The kinetics of pollen in dairy farms have been studied in a pilot study (n = 9), and exposure in a sub-sample of the ongoing European birth cohort PASTURE (n = 106). Measurements of viable microorganisms and pollen were performed in air samples. To identify factors that modulate the pollen concentration multivariate regression analyses were run. Results:, Indoor pollen (95% of Poaceae fragments and grains) were significantly higher in winter than in summer (P = 0.001) and ranged between 858 to 11 265 counts/m3 during feeding in winter, thus exceeding typical outdoor levels during the pollen season. Geometric mean in French farms was significantly higher than in German and Swiss farms (7 534, 992 and 1 079 count/m3, respectively). The presence of a ventilation system and loose housing systems significantly reduced indoor pollen levels. This pollen concentration rise after feeding was accompanied by an increase in fungal and actinomycetal levels, whereas the concentration of bacteria was not associated with feeding. Conclusions:, Farmers and their children who attend cowsheds during the feeding sessions are exposed perennially to high pollen concentrations. It might be speculated that the combined permanent exposure to microbes from livestock and grass pollen may initiate tolerance in children living on a farm. [source] Erkenntnisse über Lüftung und Energieverbrauch sowie Bodenplattendämmung aus Monitoring-Untersuchungen an einem Passivhaus-SchulgebäudeBAUPHYSIK, Issue 1 2008Søren Peper Dipl.-Ing. Über zweieinhalb Jahre Monitoring einer Passivhaus-Schule und Kindertagesstätte (KiTa) in Frankfurt a.M. zeigt behagliche raumklimatische Bedingungen bei guten Luftqualitäten. Die Heizwärmeverbrauchswerte liegen wie erwartet niedrig und zeigen Einsparungen um 90 % gegenüber dem Durchschnitt im Bestand. Auch primärenergetisch bewertet, weist die Schule beste Resultate auf. Die Ergebnisse zu weiteren Untersuchungen der effizienten Lüftungsanlage mit Wärmerückgewinnung, den umlaufenden Dämmschürzen als Alternative zur Bodenplattendämmung und dem Einfluss der Luftwechselrate durch die Eingangstüren werden vorgestellt. Monitoring of a Passive House School Building. More than two and a half years of monitoring of a Passive House school and day-care centre in Frankfurt a. M. show comfortable indoor climate and good air quality. The space heat consumption is low and shows savings of approximately 90 % as compared to average existing schools. Excellent performance was also achieved in terms of primary energy. The results of further analyses of the efficient ventilation system with heat recovery, the perimeter insulation as an alternative to floor slab insulation and the influence of the air change due to the entrance door are presented. [source] Energetisch und bauphysikalisch optimierte Sanierung eines Baudenkmals in GörlitzBAUPHYSIK, Issue 3 2007Christian Conrad Dipl.-Ing. Mit den angewendeten Sanierungsmassnahmen an einem barocken Gebäude in Görlitz (Innendämmung Straßenfassade, WDVS Hoffassade, Solaranlage, Lüftungsanlage mit WRG, Grauwassernutzung und Fußbodenabwasserheizung) wurden unter Einhaltung der Auflagen des Denkmalschutzes die Energieeffizienzklasse A+ erreicht, die Belange des Umweltschutzes berücksichtigt und die Dauerhaftigkeit und Zuverlässigkeit der Konstruktionen gewährleistet. Die erreichten Ergebnisse werden u.a. mit instationären Simulationsrechnungen (Wärme-, Luft- und Feuchtetransport in kapillarporösen Baustoffen) für die einzelnen Bauteile und instationären Simulationsrechnungen anlagentechnischer Komponenten verifiziert. Dabei wird bauphysikalisch der Einfluss der hohen Bauwerksmasse ganzjährig quantifiziert. Die Auswirkungen der eingesetzten Anlagentechnik auf historische Bauteile, wie z. B. die Holzbalkendecken, werden untersucht. Auf der Grundlage der Erfahrungen zur Vermeidung der Kondensat- und Reifbildungen bei hochdämmenden geneigten Verglasungen wurde gemeinsam mit einem ortsansässigen Glaswerk eine neue Wärmeschutzverglasung mit einer außenliegenden Beschichtung entwickelt/kombiniert und eingesetzt. Optimized energy saving rehabilitation of a baroque building monument. With the rehabilitation of the baroque building Handwerk 15 in Görlitz the authors achieved the energy efficiency class A+ under observance of all conditions from preservation of historic buildings and monuments, taking into account the environmental issues as well as durability and safety of the constructions in the house. The rehabilitation includes the internal thermal insulation of the historically valuable façade on the street side, the thermal insulation of the façade on the backyard side, the use of solar energy for hot water and for the support of heating especially in summer for heating the ground floor, a ventilation system with heat exchanger, the use of gray water generated from domestic processes such as laundry and bathing, and an underfloor heating for the ground floor with waste water as medium. The measurement results will be verified with numerical simulations (temperature, air, moisture transport in porous materials) of the separate building constructions and the technical components. The physical influence of the high building mass is quantified. The effects of the HVAC system on the historical building construction like for instance the timber beam floor will be investigated. Based on experiences about avoiding condensate and hoarfrost on inclined insulated glass together with a glass producing firm a new insulate glass with a special coating was developed. [source] Review of research into and application of chilled ceilings and displacement ventilation systems in EuropeINTERNATIONAL JOURNAL OF ENERGY RESEARCH, Issue 3 2004S. B. Riffat Abstract This paper discusses the origination, development and current status of chilled ceilings, displacement ventilation and combined systems. Current knowledge of chilled ceilings (including ceiling panels and beams), displacement ventilation and combined systems is summarised and a comprehensive review of research into chilled ceilings and displacement ventilation systems is presented. Research work has been categorized, and some conclusions made. Opportunities for further work are discussed. Copyright © 2004 John Wiley & Sons, Ltd. [source] Determination of aerial microbiological contamination in scholastic sports environmentsJOURNAL OF APPLIED MICROBIOLOGY, Issue 5 2003C. Dacarro Abstract Aims: To assess the microbiological indoor air quality (IAQ) of high school and college gyms during physical training lessons and to evaluate the effective microbiological exposure of students. Methods and Results: Air samples from 11 high school and college gyms of Pavia, Italy were collected. Total bacterial counts, total fungal counts and characterization of fungal taxa were determined. Air quality was evaluated using three microbiological contamination indices: the global index of microbiological contamination per m3 (GIMC per m3), the index of mesophilic bacterial contamination (IMC) and the amplification index (AI). Conclusions: This work testifies that air contamination in indoor gyms is always superior to that of the outdoor environment. Nevertheless, students are exposed to relatively low concentrations of airborne micro-organisms. The highest values of fungal counts and GIMC per m3 (>14 661) were observed between April and October when the central heating systems were switched off. The lowest fungal counts were detected in modern buildings equipped with forced ventilation systems. From qualitative aeromycological studies, 45 fungal taxa were identified, and different potentially allergenic species were isolated. Significance and Impact of the Study: The standardization of air sampling methods and the correct evaluation of aeromicrobiological results allow the classification of indoor air healthiness. The proposed microbiological contamination indices together with the characterization of airborne fungal taxa are useful tools for detailed description of IAQ. [source] Ausstattung von Klassenräumen mit Einrichtungen zum Temperieren, Lüften und BelichtenBAUPHYSIK, Issue 3 2009Gruppenleiterin Raumklimaqualität Runa Tabea Hellwig Dr.-Ing. Bauphysik allgemein; Energieeinsparung Abstract Fast alle Schulräume werden in Deutschland ausschließlich über Fenster mit Außenluft versorgt. Messungen haben gezeigt, dass die Belüftung der Schulräume vor allem in der kalten Jahreszeit unzureichend ist. Hybride Lüftungssysteme mit einer automatischen Unterstützung der Fensterlüftung könnten eine Möglichkeit bieten, die Häufigkeit schlechter Innenluftqualität in Schulen zu minimieren. Hierbei ist die Anordnung der dezentralen Zuluftöffnungen in den Fassaden eine der kritischsten Systemkomponenten, und es besteht gerade bei Schulgebäuden weiterer Untersuchungs- und Optimierungsbedarf. Im Rahmen des vom Bundesministerium für Wirtschaft und Technologie geförderten Verbund- projektes "Heizenergieeinsparung, thermische Behaglichkeit und gute Luftqualität in Schulgebäuden durch hybride Lüftungstechnik" werden die Eigenschaften von Klassenräumen im Landkreis Miesbach bezüglich der Temperierung, Belüftung und Belichtung aufgenommen. Die Begehung von 22 Schulen im Landkreis Miesbach ermöglicht für einen gesamten Landkreis die Bewertung der baulichen Gegebenheiten, welche die raumklimatischen Verhältnisse entscheidend beeinflussen. Die Belegungsdichte der Klassenräume im Landkreis Miesbach ist eher als normal bis gering einzustufen, da in ca. 80 % der Räume der Mindestwert von 2 m2 je Schüler eingehalten wird. 88 % der untersuchten Räume weisen eine mittlere bis hohe thermische Masse auf. Die meisten Klassenräume im Landkreis haben einen Fensterflächenanteil von 30 bis 60 %. Etwa 50 % der Räume besitzen keinen Sonnenschutz. Der bauliche sommerliche Wärmeschutz muss überwiegend als unzureichend bewertet werden. Etwa zwei Drittel der Klassenräume weisen eine gute bis mittlere Tageslichtversorgung auf. Die Klassenräume werden über Fenster belüftet. Die Fassaden besitzen vielfältige Öffnungsmöglichkeiten, wobei Drehkippflügel und Schwingflügel am häufigsten angetroffen werden. Equipment of classrooms with systems for maintaining temperature, for ventilation and for illumination. Most German classrooms are not equipped with mechanical ventilation systems. Natural ventilation controlled by the occupants opening the windows is the main way to provide fresh air. Measurements in real classrooms showed that the ventilation especially in cold season is insufficient. Hydrid ventilation systems with automatically controlled windows might reduce the prevalence of high carbon dioxide concentration inside the classrooms. The position of the air supply opening in the façade is the most sensible design task. There is still a big potential for optimization. In the frame of the project "Energy saving, thermal comfort and good indoor air quality in schools using hybrid ventilation" supported by the German Federal Ministry for Economic Affairs and Technology the properties of classrooms in the county Miesbach/Germany regarding thermal comfort, ventilation and illumination were collected. In sum data of 106 classrooms in 22 schools were collected. The density of persons is normal to low. Approximately 80% of the rooms offer at least 2 or more square meter per pupil. 88% of the investigated classrooms are built with medium or high thermal mass. The glazed facade area is between 30 and 60% for most of the classrooms. 50% of the classrooms do not have any sun shading device. The summer overheating protection by passive means is insufficient. Two thirds of the classrooms offer a good to acceptable daylight condition. The classrooms are ventilated by opening the windows. There are different opening types of the windows and several combinations of the types in the façades. Tilt and turn windows and the horizontally pivot-hung type are the most prevalent types. [source] Die Ermittlung des Jahresnutzkühlenergiebedarfs in Bürogebäuden mit dem Berechnungsverfahren nach Energieeinsparverordnung 2007 bzw.BAUPHYSIK, Issue 2 2009DIN V 1859 Energieinsparung; Technische Regelwerke Abstract Die seit 2007 gültige Energieeinsparverordnung (EnEV) schreibt für Bürogebäude eine gesamtheitliche Bilanzierung des Energiebedarfs vor, so dass neben dem Heizwärmeverbrauch und dem Energieverbrauch für Lüftungsanlagen erstmals auch der Kühlenergieverbrauch und der Stromverbrauch für Beleuchtung zu berücksichtigen ist. Die vorliegende Studie fokussiert auf den Jahreskühlenergieverbrauch von Büroräumen, welcher neben den Rechenregeln nach EnEV 2007 bzw. DIN V 18599 auch mit Hilfe der Algorithmen in der VDI 2067 oder mittels dynamischer, thermischer Simulationen ermittelt werden kann. Hierzu wird der Jahreskühlenergiebedarf für einen typischen Büroraum mit unterschiedlichen Fassadentypen nach den verschiedenen Verfahren berechnet, um Unterschiede aufzuzeigen. Abschließend wird exemplarisch der Einfluss des dem jeweiligen Verfahren zugrundeliegenden Außenklimas aufgezeigt. Determining the annual cooling energy demand for office buildings using the calculation procedure according to the 2007 Building Energy Conservation Ordinance or the DIN V 18599 standard. The German Building Energy Conservation Ordinance (EnEV), which has been in force since 2007, requires a holistic balance of the energy demand for office buildings, so that for the first time energy used for cooling and electricity used for lighting must be taken into account besides energy used for thermal heat and ventilation systems. This study focuses on the annual energy consumption for cooling offices which can be determined not only according to the calculation rules laid down in the EnEV 2007 or DIN V 18599 standards but also with the aid of algorithms specified in VDI 2067 or by means of dynamic thermal simulations. Here the annual energy demand for cooling a typical office with different types of facade is calculated by means of various calculation procedures in order to highlight the differences and deduce which types of facade react particularly sensitively. An example is used to illustrate the influence of the prevailing outdoor weather conditions for each procedure. [source] Untersuchungen zum Raumklima und zur Fensterlüftung in SchulenBAUPHYSIK, Issue 2 2009Gruppenleiterin Raumklimaqualität Bauphysik Allgemein; Energieeinsparung Abstract Es gibt mehr als 40.000 Schulgebäude in Deutschland, von denen die meisten noch auf eine Sanierung warten. Sanierungen sollen nicht nur dazu dienen, den energetischen Standard der Gebäude zu verbessern, sondern sollten in erster Linie dazu genutzt werden, die raumklimatischen Bedingungen in den Klassenräumen für Schüler und Lehrer zu verbessern. Da die meisten deutschen Schulgebäude nicht mit Raumlufttechnischen Anlagen ausgestattet sind, werden die Räume durch freie Fensterlüftung, betätigt durch die Lehrer und Schüler, belüftet. Daher ist das Fensteröffnungsverhalten der Nutzer von Interesse. Der Einfluss des Fensteröffnungsverhaltens der Nutzer auf die raumklimatischen Bedingungen in den Klassenräumen wurde in zwei Schulen untersucht. Innentemperatur, Kohlendioxidkonzentration sowie die außenklimatischen Bedingungen wurden gemessen. In einer Schule wurde die Fensteröffnungszeit erfasst. Neben hohen Kohlendioxidkonzentrationen besonders während der Heizperiode, sind einige Klassenräume im Winter zu kalt und zu warm im Sommer. Einige Klassenräume haben keinen Sonnenschutz, oder der Sonnenschutz ist unzureichend oder er behindert die Belüftung des dahinterliegenden Raumes. Die Fenster werden zu einem gewissen Grad während des Unterrichts und in den Pausen genutzt. Jedoch werden die Fenster nach dem Unterricht geschlossen und bleiben geschlossen bis zum nächsten Morgen. Es wird keine Nachtlüftung oder Lüftung in den frühen Morgenstunden praktiziert. Signifikante schwache bis moderate Korrelationen zwischen der Fensteröffnungszeit und der Innentemperatur wurden gefunden. Die Korrelation zwischen der Fensteröffnungszeit und der Außentemperatur ist in den meisten Fällen nicht signifikant oder ist nur schwach ausgeprägt. Investigations on indoor environmental conditions and natural ventilation in school buildings. There are more than 40,000 school buildings in Germany. Most of them are awaiting retrofitting. Retrofitting is not only intended to improve the energetic standards, but first of all to improve indoor environmental conditions for pupils and teachers. As most of German schools are not equipped with mechanical ventilation systems, natural ventilation controlled by the occupants opening the windows is the main way to maintain healthy and comfortable conditions in the classrooms. For that purpose the influence of window opening behaviour of the occupants on the indoor environment was measured in two German schools. Temperature and carbon dioxide concentration of the indoor air as well as the outdoor climate conditions were measured. In one school the frequency of window opening was recorded. Besides high CO2 -concentrations especially during winter, some of the investigated classrooms are additionally to cold in winter or to hot in summer. Some classrooms do not have a shading device or the shading device is insufficient or it constricts the ventilation of the room. Windows are used as controls in some degree during lessons and during the breaks. But windows get closed after lessons and stay closed until next morning. There is no night or early morning ventilation in summer. A significant weak to moderate positive correlation between total open window ratio and indoor temperature has been found. Correlation between total open window ratio and outdoor temperature is not significant in most cases or show a weak correlation coefficient. [source] | ||||||||||