AN EXPERIMENTAL STUDY OF

Transcription

1 Micro-CT and nano-ct for the hierarchical analysis of materials May 24 th, 2011 AN EXPERIMENTAL STUDY OF THE HYGRIC PERFORMANCE OF DIFFERENT INTERIOR INSULATION SYSTEMS PhD Hygrothermal analysis of interior insulation Supervisor: Staf Roels Evy Vereecken Building Physics Section Departement of Civil Engineering K.U.Leuven 1

2 CONTENTS Introduction Capillary active materials Measurement - Measurement technique - Results Conclusions 2

3 INTRODUCTION Rising energy prices CO 2 -emission excesses Building sector: large potential Low energy buildings Existing building stock (<1945)? Exterior or interior insulation Interior insulation = most risky insulation technique (Interstitial condensation, thermal bridges, frost damage, mould,...) BUT: urban environment, historical buildings Interior insulation 3

4 INTRODUCTION Interior insulation = most risky insulation technique (Interstitial condensation, thermal bridges, frost damage, mould,...) p v,sat p v 4

5 INTRODUCTION Standard solution : vapour tight systems (e.g. XPS, cellular glass, insulation + vapour retarder) BUT: reduction drying rate of the masonry wall towards the inside p v,sat p v d µd 5

6 INTRODUCTION Standard solution : vapour tight systems (e.g. XPS, cellular glass, insulation + vapour retarder) BUT: reduction drying rate of the masonry wall towards the inside Recent innovative proposals: Smart vapour retarder Hydrophilic mineral wool Capillary active insulation 6

7 CAPILLARY ACTIVE MATERIALS Vapour open + high capillary pores (e.g. Calcium silicate, wood fibre board) redistribution of liquid moisture avoidance of interstitial condensation Capillary active insulation Non capillary active insulation Theory practice? 7

8 EXPERIMENTAL TEST SETUP TEST WALLS 30 cm high 3 cm thick 5 cm insulation (except e.g. Pavadentro) 1.25 gypsum board (uncoated) A Glue mortar B Mineral wool C Mineral wool Vapour retarder D Glue mortar XPS E Glue mortar Foamglas F Masonry wall (29 cm) Glue mortar Multipor G Multipor H Glue mortar Calcium silicate I Glue mortar Pavadentro J Glue mortar Cellulose G y p s u m b o a r d K Glue mortar Cellulose Vapour retarder L Plexiglass Calcium silicate Mineral wool Masonry wall

9 EXPERIMENTAL TEST SETUP HOT BOX COLD BOX COLD BOX HOT BOX T = 2 C RH = 54% T = 35 C RH = 86% 9

10 MEASUREMENT TECHNIQUES 1. Logging RH and T at interfaces B4 B3 B2 B1 Mineral wool B 3 B 2 10

11 MEASUREMENT TECHNIQUES 2. Moisture distribution: X-ray Beer s law: I I 0 exp d wvw wdw w V d w w ln I I d w wet ln dry I exp dry I0 d I exp wet I0 d wdw Source: S. Roels, J. Carmeliet; Analysis of moisture flow in porous materials using microfocus X-ray radiography (International Journal of Heat and Mass Transfer 2006) 11

12 RESULTS 2. Moisture distribution: X-ray PAVADENTRO CELLULOSE CELLULOSE + SVR CALCIUMSILICATE Negligible increase in moisture content High increase in moisture content 12

13 RESULTS 2. Moisture distribution: X-ray GOOD CONTACT IDEAL CONTACT : - Redistribution of liquid moisture BUT, importance properties (K l,, ) glue mortar and insulation material!! AIR GAP: - NO redistribution of liquid moisture 13

14 Weight increase (g) RESULTS 3. Weight increase Vapour open, K l = 0 Vapour open, K l 0 Vapour tight systems Time (h) No insulation No insulation Mineral wool Mineral wool + SVR XPS Foamglas Multipor (with glue mortar) Multipor (without glue mortar) Calcium silicate Pavadentro Cellulose Cellulose + SVR 14

15 CONCLUSIONS Hot box cold box experiment Combined measurement technique: 1. Logging RH and T 2. Moisture distribution: X-ray 3. Weight increase X-ray projection method = Useful technique to investigate the moisture distribution (especially to study the working principle of capillary active insulation systems) ADVANTAGES - No disturbance of the material (! Capillary active systems) - Also for a high moisture content ( RH sensors) BUT: - Small walls (1D?) - Difficult for a low moisture content 15

16 Thank you for your attention! 16