Abstract
Original language  English 

Qualification  Doctor Degree 
Awarding Institution 

Supervisors/Advisors 

Award date  26 Apr 1993 
Place of Publication  Espoo 
Publisher  
Print ISBNs  9513842525 
Publication status  Published  1993 
MoE publication type  G4 Doctoral dissertation (monograph) 
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Keywords
 thermal analysis
 coupling (process)
 building components
 building envelope
 structures
 buildings
 energy consumption
 heat transmission
 air tightnes
 heat transfer
 air low
 leakage
 development
 numerical analysis
 computer programs
 simulation
 convection
 models
 theses
Cite this
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Thermal coupling of leakage air and heat flows in buildings and in building components : Development and application of numerical methods: Dissertation. / Virtanen, Markku.
Espoo : VTT Technical Research Centre of Finland, 1993. 187 p.Research output: Thesis › Dissertation › Monograph
TY  THES
T1  Thermal coupling of leakage air and heat flows in buildings and in building components
T2  Development and application of numerical methods: Dissertation
AU  Virtanen, Markku
N1  Project code: LVI30191
PY  1993
Y1  1993
N2  Numerical methods have been introduced for the thermal analysis of airleakages in building components and in buildings as a whole. Numericalmethods at the structure level are developed on the basis of physical modelling derived from the balance equations of coupled heat and airtransfer in building structures. The study focuses on crack and filtrationflows. The numerical formulation of the model equations is based on the finite difference method and the reliability of the twodimensionalnumerical methods developed at the structural level have beenexperimentally confirmed. For energy analyses of buildings, an application of the response factor method for leaky structures, which takes intoaccount the thermal coupling of transmission heat flows and the convectionheat flows of air leakages, is also introduced. A simulation procedure for the simultaneous solution of air flow and heat balances is elaborated. Inthis procedure the heat balance of a building is solvedby means of the socalled convective heat balance model as well as the response factor method developed. The air flow balance is solved in a quasi steadystatecondition, using the MOVECOMP program as a basis. In the analyses at the structure level, the thermal interactions of structures and leakage air flows in some typical air leakage cases are examined. The dependence of heat transfer (the heat recovery effect) on the leakage air flow rate, the length and location of the leakage path, the dimensions and thermal property values of the structure and on the heat transfer coefficients of the surfaces are analysed numerically. The numerical analyses made on the building level are used to study the annual interactions between the airtightness of the building envelope, air leakages and heating energy consumption. A single family house with a mechanical exhaust ventilation system was chosen for the case studied. According to analyses, it is evident that both the omission of the heat recovery effect of infiltrating/exfiltrating air and using the constant exfiltrating airflow rate tend to overestimate the calculated heating load compared with the actual heating load. Finally, thermal analyses are carried out on a house with so called dynamic walls.
AB  Numerical methods have been introduced for the thermal analysis of airleakages in building components and in buildings as a whole. Numericalmethods at the structure level are developed on the basis of physical modelling derived from the balance equations of coupled heat and airtransfer in building structures. The study focuses on crack and filtrationflows. The numerical formulation of the model equations is based on the finite difference method and the reliability of the twodimensionalnumerical methods developed at the structural level have beenexperimentally confirmed. For energy analyses of buildings, an application of the response factor method for leaky structures, which takes intoaccount the thermal coupling of transmission heat flows and the convectionheat flows of air leakages, is also introduced. A simulation procedure for the simultaneous solution of air flow and heat balances is elaborated. Inthis procedure the heat balance of a building is solvedby means of the socalled convective heat balance model as well as the response factor method developed. The air flow balance is solved in a quasi steadystatecondition, using the MOVECOMP program as a basis. In the analyses at the structure level, the thermal interactions of structures and leakage air flows in some typical air leakage cases are examined. The dependence of heat transfer (the heat recovery effect) on the leakage air flow rate, the length and location of the leakage path, the dimensions and thermal property values of the structure and on the heat transfer coefficients of the surfaces are analysed numerically. The numerical analyses made on the building level are used to study the annual interactions between the airtightness of the building envelope, air leakages and heating energy consumption. A single family house with a mechanical exhaust ventilation system was chosen for the case studied. According to analyses, it is evident that both the omission of the heat recovery effect of infiltrating/exfiltrating air and using the constant exfiltrating airflow rate tend to overestimate the calculated heating load compared with the actual heating load. Finally, thermal analyses are carried out on a house with so called dynamic walls.
KW  thermal analysis
KW  coupling (process)
KW  building components
KW  building envelope
KW  structures
KW  buildings
KW  energy consumption
KW  heat transmission
KW  air tightnes
KW  heat transfer
KW  air low
KW  leakage
KW  development
KW  numerical analysis
KW  computer programs
KW  simulation
KW  convection
KW  models
KW  theses
M3  Dissertation
SN  9513842525
T3  VTT Publications
PB  VTT Technical Research Centre of Finland
CY  Espoo
ER 