Download or read book System Performance Evaluation and Design Guidelines for Displacement Ventilation written by Qingyan Chen and published by American Society of Heating Refrigerating and Air-Conditioning Engineers. This book was released on 2003 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book presents system performance evaluation, and includes a 10-step design guideline for displacement ventilation systems for U.S. buildings. These design guidelines present two important models: 1) to calculate the temperature difference between the head and the foot level of an occupant; and 2) one to determine the ventilation effectiveness at the breathing level.The book notes that: A displacement ventilation system can provide a thermally comfortable indoor environment at a high cooling load through careful design. The indoor air quality in a space with displacement ventilation is better if the contaminant sources are associates with the heat sources. The displacement ventilation system can also save energy but requires a separate heating system if it is applied to building perimeter zones. 6 x 9, soft cover.

Download or read book Displacement Ventilation Performance written by and published by . This book was released on 1993-03-01 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Displacement Ventilation and Static Cooling Devices written by Tariq Abbas and published by . This book was released on 1999 with total page 32 pages. Available in PDF, EPUB and Kindle. Book excerpt: This volume presents the accepted practice for the design and implementation of displacement ventilation systems with and without static cooling devices, based on research as well as the views of consultants and manufacturers considered to be experts in this field. The book presents a detailed description of how displacement ventilation systems work, applications where they can be used, design issues, calculation procedures, system performance in terms of temperature, air speed, thermal comfort and indoor air quality as well as control, installation and maintenance.

Download or read book Natural Ventilation for Infection Control in Health care Settings written by Y. Chartier and published by World Health Organization. This book was released on 2009 with total page 132 pages. Available in PDF, EPUB and Kindle. Book excerpt: This guideline defines ventilation and then natural ventilation. It explores the design requirements for natural ventilation in the context of infection control, describing the basic principles of design, construction, operation and maintenance for an effective natural ventilation system to control infection in health-care settings.

Download or read book Industrial Ventilation Design Guidebook written by Howard D. Goodfellow and published by Academic Press. This book was released on 2021-06-04 with total page 745 pages. Available in PDF, EPUB and Kindle. Book excerpt: Industrial Ventilation Design Guidebook, Volume 2: Engineering Design and Applications brings together researchers, engineers (both design and plants), and scientists to develop a fundamental scientific understanding of ventilation to help engineers implement state-of-the-art ventilation and contaminant control technology. Now in two volumes, this reference contains extensive revisions and updates as well as a unique section on best practices for the following industrial sectors: Automotive; Cement; Biomass Gasifiers; Advanced Manufacturing; Industrial 4.0); Non-ferrous Smelters; Lime Kilns; Pulp and Paper; Semiconductor Industry; Steelmaking; Mining. - Brings together global researchers and engineers to solve complex ventilation and contaminant control problems using state-of-the-art design equations - Includes an expanded section on modeling and its practical applications based on recent advances in research - Features a new chapter on best practices for specific industrial sectors

Download or read book Ventilation of Buildings written by H.B. Awbi and published by Routledge. This book was released on 2004-06-02 with total page 537 pages. Available in PDF, EPUB and Kindle. Book excerpt: Hazim Awbi's Ventilation of Buildings has become established as the definitive text on the subject. This new, thoroughly revised, edition builds on the basic principles of the original text drawing in the results of considerable new research in the field. A new chapter on natural ventilation is also added and recent developments in ventilation concepts and room air distribution are also considered. The text is intended for the practitioner in the building services industry, the architect, the postgraduate student undertaking courses or research in HVAC, building services engineering, or building environmental engineering, and the undergraduate studying building services as a major subject. Readers are assumed to be familiar with the basic principles of fluid flow and heat transfer and some of the material requires more advanced knowledge of partial differential equations which describe the turbulent flow and heat transfer processes of fluids. The book is both a presentation of the practical issues that are needed for modern ventilation system design and a survey of recent developments in the subject

Download or read book The Performance of Displacement Ventilation Systems written by Elisabeth Mundt and published by . This book was released on 1996 with total page 155 pages. Available in PDF, EPUB and Kindle. Book excerpt: In a displacement ventilated room the air flow pattern is mainly governed by the convection flows from different heat sources. The interaction of the convection flows influences the contamination distribution in the room. This distribution also depends on the position and strength of the contamination sources. Local va lues at the same height in the room may differ significantly. The distribution i s also sensitive to 'disturbances' in the form of e.g. persons mowing around. Th e factors governing the air flow patterns were investigated by measurements of t emperature gradients, convection flow rates in plumes and contamination distribu tions. The efficiency of the ventilation was measured for many different combina tions of ventilation flow rates, heat loads and contamination sources. The tempe rature gradient was strongly correlated to the ventilation flow rate and very st able. People mowing around or walking in and out of the room did not influence t he shape of the gradient. Models for the temperature gradient in balanced and un balanced conditions were developed. The convection flow rate in a plume and its maximum height were influenced by the temperature gradient. Models for the conve ction flow rate in a plume from a point or a line source are given including the height where the plumes disintegrate due to the gradient in the surroundings. T he air change efficiency increased with the ventilation flow rate as long as the convection plumes reached the ceiling, and decreased when the plume disintegrat ed below the ceiling. The contaminant removal effectiveness was dependent on the position of the contamination (tracer gas) source and on the interaction of the convection flows in the room. A small change in the position of the tracer gas source caused a great change in the contaminant removal effectiveness. The inter action of the different convection flows in the room also caused a great variati on in the local air quality indices measured at the same level at different posi tions both with the tracer gas source in a plume and outside a plume. When the t racer gas source was outside a plume a heavy tracer gas spread to the floor in a ll measured cases while a light tracer gas spread to the floor only at low tempe rature gradients independent of the ventilation flow rate. Opening and closing o f a door was enough to ...

Download or read book Healthy Buildings written by JOSEPH G. ALLEN and published by Harvard University Press. This book was released on 2022-10-18 with total page 337 pages. Available in PDF, EPUB and Kindle. Book excerpt: Buildings can make us sick or keep us well. Diseases and toxins course through indoor spaces, making us ill. Meanwhile, better air quality and light levels improve productivity. At a time when the COVID-19 pandemic has us focused more than ever on indoor air quality, Healthy Buildings shows how much we have to gain from human-centered design.

Download or read book Performance Evaluation and Development of Design Guidelines for Displacement Ventilation written by Qingyan Chen and published by . This book was released on 1999 with total page 230 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Materials for Energy Efficiency and Thermal Comfort in Buildings written by Matthew R Hall and published by Elsevier. This book was released on 2010-04-21 with total page 761 pages. Available in PDF, EPUB and Kindle. Book excerpt: Almost half of the total energy produced in the developed world is inefficiently used to heat, cool, ventilate and control humidity in buildings, to meet the increasingly high thermal comfort levels demanded by occupants. The utilisation of advanced materials and passive technologies in buildings would substantially reduce the energy demand and improve the environmental impact and carbon footprint of building stock worldwide.Materials for energy efficiency and thermal comfort in buildings critically reviews the advanced building materials applicable for improving the built environment. Part one reviews both fundamental building physics and occupant comfort in buildings, from heat and mass transport, hygrothermal behaviour, and ventilation, on to thermal comfort and health and safety requirements.Part two details the development of advanced materials and sustainable technologies for application in buildings, beginning with a review of lifecycle assessment and environmental profiling of materials. The section moves on to review thermal insulation materials, materials for heat and moisture control, and heat energy storage and passive cooling technologies. Part two concludes with coverage of modern methods of construction, roofing design and technology, and benchmarking of façades for optimised building thermal performance.Finally, Part three reviews the application of advanced materials, design and technologies in a range of existing and new building types, including domestic, commercial and high-performance buildings, and buildings in hot and tropical climates.This book is of particular use to, mechanical, electrical and HVAC engineers, architects and low-energy building practitioners worldwide, as well as to academics and researchers in the fields of building physics, civil and building engineering, and materials science. - Explores improving energy efficiency and thermal comfort through material selection and sustainable technologies - Documents the development of advanced materials and sustainable technologies for applications in building design and construction - Examines fundamental building physics and occupant comfort in buildings featuring heat and mass transport, hygrothermal behaviour and ventilation

Download or read book Air Distribution in Rooms written by H.B. Awbi and published by Elsevier. This book was released on 2000 with total page 746 pages. Available in PDF, EPUB and Kindle. Book excerpt: The air distribution in occupied spaces is a major issue of public concern. It is widely recognized that the quality of air and the nature of airflow can affect the health of occupants and the energy consumed in buildings and transport vehicles. ROOMVENT is the principal international conference in the field of air distribution. It was first initiated in 1987 by SCANVAC, the Scandinavian Federation of Heating, Ventilating and Sanitary Engineering Associations in Denmark, Finland, Iceland, Norway and Sweden. The aim of the Conference is to bring together researchers from universities and research institutes, engineers from industry and government officials and policy makers, with the goal of experiencing the latest techniques for measuring and analyzing indoor air flow, the visualization of indoor air flow patterns, the evaluation of ventilation parameters and the most recent developments in computer simulation techniques of room airflow. It is hoped that the theme of ROOMVENT 2000 "Ventilation for Health and Sustainable Environment" will set the scene for room air distribution research and development for the new millennium.

Download or read book A Ventilation Strategy Based on Confluent Jets written by Setareh Janbakhsh and published by Linköping University Electronic Press. This book was released on 2015-04-27 with total page 96 pages. Available in PDF, EPUB and Kindle. Book excerpt: This study presents air distribution systems that are based on confluent jets; this system can be of interest for the establishment of indoor environments, to fulfill the goals of indoor climate and energy-efficient usage. The main objective of this study is to provide deeper understanding of the flow field development of a supply device that is designed based on wall confluent jets and to investigate the ventilation performance by experimental and numerical methods. In this study, the supply device can be described as an array of round jets on a flat surface attached to a side wall. Multiple round jets that issue from supply device apertures are combined at a certain distance downstream from the device and behave as a united jet or so-called confluent jets. Multiple round jets that are generated from the supply device move downward and are attached to the wall at the primary region, due to the Coanda effect, and then they become wall confluent jets until the floor wall is reached. A wall jet in a secondary region is formed along the floor after the stagnation region. The characteristics of the flow field and the ventilation performance of conventional wall confluent jets and modified wall confluent jets supply devices are investigated experimentally in an office test room. The study of the modified wall confluent jets is intended to improve the efficiency of the conventional one while maintaining acceptable thermal comfort in an office environment. The results show that the modified wall confluent jets supply device can provide acceptable thermal comfort for the occupant with lower airflow rate compared to the conventional wall confluent jets supply device. Numerical predictions using three turbulence models (renormalization group (RNG k– ?), realizable (Re k– ?), and shear stress transport (SST k– ?) are evaluated by measurement results. The computational box and nozzle plate models are used to model the inlet boundary conditions of the nozzle device. In the isothermal study, the wall confluent jets in the primary region and the wall jet in the secondary region, when predicted by the three turbulence models, are in good agreement with the measurements. The non-isothermal validation studies show that the SST k– ? model is slightly better at predicting the wall confluent jets than the other two models. The SST k– ? model is used to investigate the effects of the nozzle diameter, number of nozzles, nozzle array configuration, and inlet discharge height on the ventilation performance of the proposed wall confluent jets supply device. The nozzle diameter and number of nozzles play important roles in determining the airflow pattern, temperature field, and draught distribution. Increased temperature stratification and less draught distribution are achieved by increasing the nozzle diameter and number of nozzles. The supply device with smaller nozzle diameters and fewer nozzles yields rather uniform temperature distribution due to the dominant effect of mixing. The flow behavior is nearly independent of the inlet discharge height for the studied range. The proposed wall confluent jets supply device is compared with a mixing supply device, impinging supply device and displacement supply device. The results show that the proposed wall confluent jets supply device has the combined behavior of both mixing and stratification principles. The proposed wall confluent jets supply device provides better overall ventilation performance than the mixing and displacement supply devices used in this study. This study covers also another application of confluent jets that is based on impinging technology. The supply device under consideration has an array of round jets on a curve. Multiple jets issue from the supply device aperture, in which the supply device is positioned vertically and the jets are directed against a target wall. The flow behavior and ventilation performance of the impinging confluent jets supply device is studied experimentally in an industrial premise. The results show that the impinging confluent jets supply device maintains acceptable thermal comfort in the occupied zone by creating well-distributed airflow during cold and hot seasons.

Download or read book A Guide to Energy Efficient Ventilation written by Martin W. Liddament and published by . This book was released on 1996 with total page 254 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Displacement Ventilation written by Håkon Skistad and published by Research Studies PressLtd. This book was released on 1994 with total page 146 pages. Available in PDF, EPUB and Kindle. Book excerpt: In displacement ventilation systems, the principle of buoyancy is utilised to remove warm contaminated air from an occupied area. The main driving force is natural convection: instead of attempting to combat the forces of natural convection as in mechanical dilution ventilation, displacement systems supply and exhaust air in such a way as not to interfere with the convection currents set up by the heat sources in a space. Provided that pollution and heat sources are in close proximity, displacement ventilation can give better air quality than dilution ventilation, but good design is necessary to ensure that unacceptable vertical temperature gradients and cold draughts along the floor are avoided.

Download or read book Performance of Displacement Ventilation at Pori Works Ltd written by Raimo Niemelä and published by . This book was released on 1996 with total page 34 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Ventilation Systems written by Hazim B. Awbi and published by Psychology Press. This book was released on 2008 with total page 459 pages. Available in PDF, EPUB and Kindle. Book excerpt: This comprehensive account of the methods used for ventilating buildings and the type of systems currently in use for achieving the desired indoor environment will be of particular interest to graduate students, professionals and researchers.

Download or read book On the performance of stratified ventilation written by Ulf Larsson and published by Linköping University Electronic Press. This book was released on 2018-08-20 with total page 108 pages. Available in PDF, EPUB and Kindle. Book excerpt: People nowadays spend most of their time indoors, for example in their homes, cars, in trains, at work, etc. In Sweden, the energy demand in the built environment is a growing issue. The building sector accounts for 40% of total energy use and 15% of total CO2 emissions, and around one-third of the energy use in the world is related to providing a healthy and good comfort indoors. To achieve acceptable indoor climates new designs for the ventilation systems have been proposed in recent decades, among them stratified ventilation systems. Stratified ventilation is a concept that often allows good performance for both indoor air quality and thermal comfort. Stratified ventilation systems are effective in reducing cross contamination, since there is virtually no mixing in the space; the temperature and the pollutant concentration increase linearly from the heat source with the height of the occupied zone. There are many different ventilation supply devices using the stratified principle, such as displacement supply device (DSD), impinging jet supply device (IJSD) and wall confluent jet supply device (WCJSD). The main aim of this thesis is to analyze and compare different supply devices based on stratified ventilation, with different setups, related to thermal indoor climate, energy efficiency and ventilation efficiency. The ultimate goal is to contribute to an increased understanding of how ventilation systems with stratified supply devices perform. Two scientific methods have mainly been used in this thesis, i.e., experimental and numerical investigations. For numerical experiments the CFD (Computational Fluid Dynamics) code ANSYS and FIDAP have been used. Experimental studies have been performed with thermocouples, Hot-Wire Anemometry (HWA) and Hot-Sphere Anemometry, thermal comfort measurement equipment and tracer gas measurement equipment. This thesis mainly focuses on three research questions: Interaction between a supply device based on stratified ventilation and downdraft from windows; Flow behavior, energy performance and air change effectiveness for different supply devices based on stratified ventilation; and Thermal comfort for different supply devices based on stratified ventilation. Research question one showed that the arrangement of displacement supply device and window in cold climate has significant effect on the flow pattern below the window. Different supply airflow rates have an effect on both the velocity and the temperature of the downdraft. In this case the velocity decreased by approximately 9.5% and the temperature in the downdraft decreased 0.5°C when the flowrate from the supply device increased from 10 to 15 l/s. Research question two showed that airflow patterns between different air supply systems were essentially related to characteristics of air supply devices, such as the type, configuration and position, as well as air supply velocities and momentum. For WCJSD, IJSD and DSD, positions of heat sources (such as occupant, computers, lights and external heat sources) played an important role in formation of the room airflow pattern. One interesting observation is that the temperature in the occupied zone is lower and a more stratified temperature field implies a more efficient heat removal by a stratified air supply device. The results revealed that the lowest temperature in the occupied zone was achieved for DSD, but with IJSD and WCJSD slightly warmer, while the system with a mixing supply device (MSD) showed a much higher temperature. The results confirm that air change effectiveness (ACE) for the DSD, WCJSD and IJSD is close to each other. However, MSD shows lower ACE in all the present papers than IJSD, WCJSD and DSD. Research question three showed that ventilation systems with stratified supply devices in almost all of the studied cases showed an acceptable level for predicted percentage dissatisfied (PPD), predicted mean vote (PMV) and percentage dissatisfied due to draft (DR). If comparing ventilation systems, using IJSD, WCJSD or DSD with MSD always showed thermal comfort better or at the same level. Människor spenderar en stor del av sin tid inomhus, exempelvis i sina bostäder och bilar, på tåg och på arbetet. Sveriges energibehov i den byggda miljön har en växande trend. Byggnadssektorn står för 40 % av det totala energibehovet och för 15 % av CO2 utsläppet och för cirka en tredjedel av energianvändningen i världen för att tillhandahålla en hälsosam och bra inomhusmiljö. För att skapa en bra inomhusmiljö har nya sätt att ventilera inomhusmiljön utvecklats under de senaste årtiondena. De olika principer som används för att ventilera en byggnad kan indelas i: kolvströmning, omblandande strömning och deplacerande strömning. De genererar rumsförhållanden som ger olika fördelning av hastighet, temperatur och föroreningar i det ventilerade utrymmet. Stratifierad ventilation är ett koncept som ofta ger ett bra utfall av både inomhusluftkvalitet och termisk komfort. Stratifierade system är effektiva för att minska korskontaminering, eftersom det nästan inte finns någon omblandning i rummet, temperaturen och föroreningskoncentration ökar linjärt från värmekällan med höjden i vistelsezonen. Det finns många olika ventilationsdon som använder den stratifierade principen, såsom deplacerande ventilationsdon (DSD), impinging jet-ventilationsdon (IJSD) och väggbaserad confluent jet-ventilationsdon (WCJSD). Huvudsyftet med denna avhandling är att analysera och jämföra olika tilluftsdon baserat på stratifierad princip i olika rumskonfigurationer med avseende på termiskt inomhusklimat, energieffektivitet och ventilationseffektivitet. Det yttersta målet är att bidra till ökad förståelse för hur ventilationssystem med olika stratifierade tilluftsdon fungerar. Två vetenskapliga metoder har huvudsakligen använts i denna avhandling: experimentella och numeriska analyser. För numeriska analyser har CFD (Computational Fluid Dynamics) använts. De simuleringsprogram som utnyttjats för detta ändamål är ANSYS och FIDAP. Experimenten har utförts med hjälp av termoelement, varmtråds- och varmsfärsteknik, mätutrustning för termisk komfort och mätutrustning för spårgas. Denna avhandling fokuserar framför allt på tre forskningsfrågor: interaktion mellan ett tilluftsflöde från ett deplacerande don och kallraset från ett fönster; strömningsbilden, energiprestandan och luftbyteseffektiviteten för olika tilluftsdon baserat på stratifierad ventilation; och termisk komfort för olika tilluftsdon baserade på stratifierad ventilation. Forskningsfråga ett visade att kombinationen av tilluftsflöde genom ett deplacerande don och fönster i kallt klimat har tydlig effekt på strömningsbilden för kallraset under fönstret. Olika tilluftsflöden har en effekt på både hastigheten och temperaturen i kallraset. I detta fall minskade hastigheten med ca 9,5% och temperaturen i kallraset minskade med 0,5°C när flödeshastigheten från tilluftsdonet ökade från 10 till 15 l/s. Forskningsfråga två visade att luftflödesmönstren mellan olika luftförsörjningssystem väsentligen var relaterade till egenskaper hos tilluftsdonen, såsom typ, konfiguration och position samt lufttillförselhastigheter och impulskraft. För WCJSD, IJSD och DSD spelade värmekällans placering, d.v.s. människor, datorer, belysning och externa värmekällor, en viktig roll vid utformningen av rummets luftflödesmönster. En intressant observation är att temperaturen i vistelsezonen är lägre och rummet har ett mer stratifierat temperaturfält, vilket innebär en effektivare ventilering av den zonen. Resultaten visade att den lägsta temperaturen i vistelsezonen uppnåddes för DSD medan IJSD och WCJSD visade en något högre temperatur, systemet med ett omblandande don (MSD) visade en påtagligt högre temperatur. Resultaten bekräftar också att luftförändringseffektiviteten (ACE) för DSD, WCJSD och IJSD ligger nära varandra. MSD visar dock i alla ingående artiklar lägre ACE än IJSD, WCJSD och DSD. Forskningsfråga tre visade att ventilationssystem med stratifierade tilluftsdon i nästan samtliga studerade fallen haren acceptabel nivå för predicted mean vote (PPD), predicted mean vote (PMV) och percentage dissatisfied due to draft (DR). Om man jämförde ventilationssystem IJSD, WCJSD eller DSD med MSD visade det sig alltid att den termiska komforten var bättre eller på samma nivå som för MSD.