Indoor Air Quality: Combining Air Humidity with Construction

3,42

MB

Moisture

205

stron

5253

ID

University of Strathclyde

2005

rok

Acknowledgements

List of Symbols

Chapter 1 Indoor air quality . 1

1.1 Introduction 1

1.2 Factors affecting indoor air quality .. .... 2

1.3 Impacts on building performance and health . 3

1.4 Health aspects of indoor air quality ..4

1.5 Research objectives and thesis outline 8

Chapter 2: Review of heat, air and moisture transfer modelling . 12

2.1 Porous medium heat and mass transfer . 12

2.1.1 Moisture flow model . .13

2.1.2 Heat, air and moisture transport through porous medium 20

2.1.3 The IEA Annex XIV enquiry on HAM codes 21

2.2 Zone moisture transfer .23

2.2.1 Air humidity and energy balance 23

Chapter 3: Review of indoor air flow modelling with CFD .. 27

3.1 Introduction .. 27

3.2. Co-located grid system 47

3.2.1 Numerical solution and algorithm 47

3.2.2 SIMPLE algorithm for a co-located grid arrangement .. 53

3.3 Turbulence modelling 60

3.3.1 Near-wall treatments . .. 66

3.4 Application of CFD to indoor air quality 79

3.5 Commonalities between HAM and CFD models 82

Chapter 4: Review of boundary layer theory . .86

4.1 Convective surface transfers . .86

4.2. Boundary layer classification . .. .. .87

4.2.1 Velocity boundary layer . ... .. 88

4.2.2 Thermal boundary layer 88

4.2.3 Concentration boundary layer .90

4.2.4 Transfer equations 91

4.3 Heat and Mass Transfer Analogy 94

4.3.1 Correlations for convective mass transfer coefficient . .. 96

4.4 Boundary conditions as they relate to buildings . 101

Chapter 5: Conflation mechanism 104

5.1 Coupling approaches. 104

5.1.1 Staged coupling . .. 104

5.2 The conflation problem. 108

5.2.1 The conflation technique 110.

5.2.2 Two-time step dynamic coupling ..116

5.2.3 Coupling of 1D HAM model to 3D CFD model .. 122

5.3 Configuration mechanism 126

5.3.1 Factors that impact on the convection heat and mass transfer coefficient 127

5.4 Moisture control algorithm..129

5.4.1 Free convection flow .... 133

5.5 Moisture desorption/absorption at the interface 138

5.5.1 CFD model adjustments 138

5.5.2 HAM model adjustments147

Chapter 6: Conclusion and Future work . .. .150

6.1 Conclusion . 150

6.2 Future work 153

6.2.1 Coding . 153

6.2.2 Material properties 154

6.2.3 Moisture transport models . 154

6.2.4 Experiments 154

APPENDICES

A: Mathematical model for moisture transport 155

B: Overview - I.E.A. Annex XIV classification of HAM codes .165

C: The sequential solution procedure 167

D: Alternative near-wall treatments .170

E: Boundary layer theory - significant dimensionless parameters . 173

F. Characterisation of the energy transfer mechanism at internal surfaces by ESP-r 177

REFERENCES .184