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Ventilation and window opening in schools, Experiments and Analysis

Nordquist, Birgitta LU (2002) In Report TABK 1024.
Abstract (Swedish)
Popular Abstract in Swedish

Syftet har varit att studera tillämpningen av ventilation i skolbyggnader. Huvuddelen av avhandlingen behandlar vädring av klassrum. Analytiska modeller med vilka luftutbytet orsakat av vädring kan beräknas föreslås. Ett mål är att modellerna skall utgöra ett verktyg för projektörer och brukare. Modellerna skall kunna användas när man vill bestämma tidslängden för vädringen respektive hur många fönster som skall öppnas.



Spårgasmätningar har genomförts dels i ett mindre testrum samt i klassrum. De speciella förhållanden som råder vid vädring kräver en vidareutvecklad beräkningsmetod för att kunna bestämma luftutbytet som erhålls vid spårgasmätningarna. En beräkningsmetod för... (More)
Popular Abstract in Swedish

Syftet har varit att studera tillämpningen av ventilation i skolbyggnader. Huvuddelen av avhandlingen behandlar vädring av klassrum. Analytiska modeller med vilka luftutbytet orsakat av vädring kan beräknas föreslås. Ett mål är att modellerna skall utgöra ett verktyg för projektörer och brukare. Modellerna skall kunna användas när man vill bestämma tidslängden för vädringen respektive hur många fönster som skall öppnas.



Spårgasmätningar har genomförts dels i ett mindre testrum samt i klassrum. De speciella förhållanden som råder vid vädring kräver en vidareutvecklad beräkningsmetod för att kunna bestämma luftutbytet som erhålls vid spårgasmätningarna. En beräkningsmetod för spårgasmätningar vid vädring föreslås. De analytiska modellerna har jämförts med mätningarna. Resultatet visar relativt bra överensstämmelse vilket innebär att de föreslagna modellerna kan användas när grova uppskattningar eftersträvas.



Effkten vädring har på ett mekaniskt till- och frånluftssystem har undersökts genom beräkningar med datorprogrammet PFS. Det är endast vid höga vindhastigheter som vädring stör flödena i systemet.



Avhandlingen innefattar två studier vilka behandlar mekanisk ventilation. Ett kanalsystem utan möjlighet till injustering har studerats med programmet PFS. Ett antal klassrum antas vara placerade intill varandra. Flödena till respektive rum antas vara lika och grenkanalerna till respektive rum är placerade på samma avstånd. Resultaten visar att ett kanalsystem för tilluft kan utformas utan möjlighet till injustering. Ett frånluftssystem kräver emellertid injustering för att erhålla flöden av samma storleksordning från alla rum.



Värmeåtervinning har även studerats genom beräkningar. Energibehovet och de totala kostnaderna under hela drifttiden har beräknats. Det visade sig att värmeåtervinning lönar sig även för en relativt begränsad drifttid under året. En känslighetsanalys visar vilka faktorer som är av betydelse vid dimensioneringen av en värmeväxlare. (Less)
Abstract
The objective of this thesis is to study the application of ventilation in schools buildings. A number of studies of the application of different forms of ventilation are presented. The main part of the thesis focuses on window opening in a classroom. Analytical models for calculation of the air change caused by window airing are proposed. The models are intended to be a tool for designers and occupants which they can use when they want to know how long a window should be open and how many windows should be opened.



Tracer gas experiments have been performed both in a small test room and in classrooms. The specific conditions concerning airing require a special calculation method to determine the air change obtained... (More)
The objective of this thesis is to study the application of ventilation in schools buildings. A number of studies of the application of different forms of ventilation are presented. The main part of the thesis focuses on window opening in a classroom. Analytical models for calculation of the air change caused by window airing are proposed. The models are intended to be a tool for designers and occupants which they can use when they want to know how long a window should be open and how many windows should be opened.



Tracer gas experiments have been performed both in a small test room and in classrooms. The specific conditions concerning airing require a special calculation method to determine the air change obtained during the tracer gas measurements. New methods for dealing with this have been proposed. The analytical models have been compared with the measurements. The results show that agreement is quite good and that the models can be used when rough estimates are of interest.



The effect window airing has on a mechanical supply and exhaust system has been investigated by calculations with the computer program PFS. It is only when wind velocities are high that airing disturbs the flows in the system.



The thesis include two studies concerning mechanical ventilation. A duct system with no means of balancing has been studied by calculation with the program PFS. A number of classrooms are assumed to be located next to each other. It is assumed that the flows to each room are equal and that the branch ducts to each room are equally spaced. The results show that a supply duct system may be designed without balancing. An exhaust duct system however requires balancing if the flows exhausted from the classrooms are to be of the same magnitude.



Heat recovery in a ventilation system has also been studied by calculations. The energy need and the total costs including the whole service life have been calculated. It was found that heat recovery pays off even for a rather limited operating time. A sensitivity analysis has shown what factors are of significance when a heat exchanger is designed. (Less)
Please use this url to cite or link to this publication:
author
opponent
  • Fahlén, Per, Göteborg
organization
publishing date
type
Thesis
publication status
published
subject
keywords
heat exchanger efficiency, duct design, balancing, disturbance, tracer gas measurements, analytical model, window opening, single-sided ventilation, ventilation, schools, sensitivity analysis, Building construction, Byggnadsteknik
in
Report TABK
volume
1024
pages
308 pages
publisher
Lund University, Lund Institute of Technology, Division of Building Services, P.O. Box 118, SE-22100 LUND, Sweden,
defense location
A:B, Arkitektskolan, Sölvegatan 24, Lund
defense date
2002-11-29 10:15
external identifiers
  • other:ISRN: LUTADL/TABK- -1024-SE
ISSN
1103-4467
language
English
LU publication?
yes
id
4929ff5e-ff52-48da-ba11-67203ac711ce (old id 20664)
date added to LUP
2007-05-28 10:44:07
date last changed
2016-09-19 08:44:55
@phdthesis{4929ff5e-ff52-48da-ba11-67203ac711ce,
  abstract     = {The objective of this thesis is to study the application of ventilation in schools buildings. A number of studies of the application of different forms of ventilation are presented. The main part of the thesis focuses on window opening in a classroom. Analytical models for calculation of the air change caused by window airing are proposed. The models are intended to be a tool for designers and occupants which they can use when they want to know how long a window should be open and how many windows should be opened.<br/><br>
<br/><br>
Tracer gas experiments have been performed both in a small test room and in classrooms. The specific conditions concerning airing require a special calculation method to determine the air change obtained during the tracer gas measurements. New methods for dealing with this have been proposed. The analytical models have been compared with the measurements. The results show that agreement is quite good and that the models can be used when rough estimates are of interest.<br/><br>
<br/><br>
The effect window airing has on a mechanical supply and exhaust system has been investigated by calculations with the computer program PFS. It is only when wind velocities are high that airing disturbs the flows in the system.<br/><br>
<br/><br>
The thesis include two studies concerning mechanical ventilation. A duct system with no means of balancing has been studied by calculation with the program PFS. A number of classrooms are assumed to be located next to each other. It is assumed that the flows to each room are equal and that the branch ducts to each room are equally spaced. The results show that a supply duct system may be designed without balancing. An exhaust duct system however requires balancing if the flows exhausted from the classrooms are to be of the same magnitude.<br/><br>
<br/><br>
Heat recovery in a ventilation system has also been studied by calculations. The energy need and the total costs including the whole service life have been calculated. It was found that heat recovery pays off even for a rather limited operating time. A sensitivity analysis has shown what factors are of significance when a heat exchanger is designed.},
  author       = {Nordquist, Birgitta},
  issn         = {1103-4467},
  keyword      = {heat exchanger efficiency,duct design,balancing,disturbance,tracer gas measurements,analytical model,window opening,single-sided ventilation,ventilation,schools,sensitivity analysis,Building construction,Byggnadsteknik},
  language     = {eng},
  pages        = {308},
  publisher    = {Lund University, Lund Institute of Technology, Division of Building Services, P.O. Box 118, SE-22100 LUND, Sweden,},
  school       = {Lund University},
  series       = {Report TABK},
  title        = {Ventilation and window opening in schools, Experiments and Analysis},
  volume       = {1024},
  year         = {2002},
}