Effect of Ageing on Service Life of Vacuum Insulation Panels

Transcription

1 ZEB Effect of Ageing on Service Life of Vacuum Insulation Panels Erlend Wegger a, Bjørn Petter Jelle ab, Erland Sveipe a, Steinar Grynning b, Ruben Baetens c, Jan Vincent Thue a a Department of Civil and Transport Engineering, Norwegian University of Science and Technology (NTNU), NO-7491 Trondheim, Norway. b Department of Materials and Structures,, NO-7465 Trondheim, Norway. c Department of Civil Engineering, Catholic University of Leuven (KUL), B-3001 Heverlee, Belgium Building Enclosure Science & Technology (BEST ), Portland, Oregon, U.S.A, April,

2 Introduction Vacuum Insulation Panels (VIP) High-tech state-of-the-art thermal insulation solution Ageing of VIPs highly dependent on water content and gas pressure Graphical plots relevant for service life prediction of VIPs provided Discussion on accelerated ageing of VIPs 2

3 VIP Buildup Porous core Usually pressed fumed silica (SiO 2 ) Air and water vapour tight foil maintaining vacuum in the VIP Various foil configurations: Simmler et al Willems et al

4 Water Content of VIP vs. Time w Qwv, tot pwv, sat ( T ) t m ( ) (1 VIP, dryk ) X t k e out 4

5 Air Pressure in VIP vs. Time p( t) p ( p p ) e app app init T p Q m 0 gas, tot TV 0 t 5

6 Thermal Conductivity of VIP vs. Time p p u c c c c g wv pg pwv u du get g des w des w (1 ) (1 ) (1 ) p p u d c ( t t )/ c ( t t )/ c ( t t )/ pg; e e pwv; e e e e g wv 6

7 Accelerated Ageing - Temperature p p u c c c c g wv pg pwv u Q( T ) Q( T )e 0 E a 1 1 ( ) R T T 0 7

8 Accelerated Ageing - Pressure p( t) p ( p p ) e app app init T p Q m 0 gas, tot TV 0 t 8

9 Accelerated Ageing - Pressure X t k e w Q wv, tot wv, sat ( T) t ( ) (1 VIP, dry ) out m p k 9

10 Accelerated Ageing - Pressure p p u c c c c g wv pg pwv u du get g des w des w (1 ) (1 ) (1 ) p p u d c ( t t )/ c ( t t )/ c ( t t )/ pg; e e pwv; e e e e g wv 10

11 Accelerated Ageing - Experiments Temperature Ageing CUAP 12.01/30 Cycling for 8 cycles. Each 24 h cycle consists of 80 C for 8 h and -15 C for 16 h. 80 C for 180 days (180 x 24 h). Thermal conductivity measurements at certain ageing intervals. Climate Ageing NT Build 495 UV radiation (UVA = 33 W/m 2, UVB = 2.4 W/m 2 ) and IR radiation giving a black panel temperature of 63 C. Water spray (15 dm 3 /(m 2 h)). Freezing at -20 C. Thawing at laboratory climate. Each 4 h cycle consists of 1 h of each of the above 4 exposures, i.e. 6 cycles per day (24 h). Total ageing duration to be determined. Thermal conductivity measurements at certain ageing intervals. 11

12 Thermal Conductivity Accelerated Ageing - Experiments Some swelling of the CUAP panel occured between days 50 and 100, thus increasing the thermal conductivity 12

13 Thermal Resistance Accelerated Ageing - Experiments 13

14 Conclusions A summary of ageing relationships for VIPs are provided Changes in air pressure, water content and thermal conductivity plotted for a time span of 100 years Accelerated ageing with respect to temperature, humidity and pressure has been investigated Results of some preliminary ageing experiments have been presented 14

15 Acknowledgements This work has been supported by the Research Council of Norway and several partners through the SINTEF and NTNU research project Robust Envelope Construction Details for Buildings of the 21st Century (ROBUST). The company va-q-tec, by Roland Caps, is acknowledged for supplying the vacuum insulation panel test samples. References R. Baetens, B. P. Jelle, J. V. Thue, M. J. Tenpierik, S. Grynning, S. Uvsløkk and A. Gustavsen, "Vacuum insulation panels for building applications: A review and beyond", Energy and Buildings, 42, , CUAP 12.01/30, Factory made vacuum insulation panels, Nordtest Method, NT Build 495, Building materials and components in the vertical position: Exposure to accelerated climatic strains, Nordtest, H. Schwab, U. Heinemann, A. Beck, H.-P. Ebert and J. Fricke, Permeation of different gases through foils used as envelopes for vacuum insulation panels, Journal of Thermal Envelope & Building Science, 28, , H. Schwab, U. Heinemann, A. Beck, H.-P. Ebert and J. Fricke, Dependence of thermal conductivity on water content in vacuum insulation panels with fumed silica kernels, Journal of Thermal Envelope & Building Science, 28, , H. Schwab, U. Heinemann, J. Wachtel, H.-P. Ebert and J. Fricke, Predictions for the increase in pressure and water content of vacuum insulation panels (VIPs) integrated into building constructions using model calculations, Journal of Thermal Envelope & Building Science, 28, , H. Schwab, U. Heinemann, A. Beck, H.-P. Ebert and J. Fricke, Prediction of service life for vacuum insulation panels with fumed silica kernel and foil cover, Journal of Thermal Envelope & Building Science, 28, , H. Simmler, S. Brunner, U. Heinemann, H. Schwab, K. Kumaran, P. Mukhopadhyaya, D. Quènard, H. Sallèe, K. Noller, E. Kücküpinar- Niarchos, C. Stramm, M. Tenpierik, H. Cauberg and M. Erb, Vacuum Insulation Panels. Study on VIP-Components and Panels for Service Life Prediction in Building Applications (Subtask A), HiPTI - High Performance Thermal Insulation, IEA/ECBCS Annex 39, September M. Tenpierik, W. van der Spoel and H. Cauberg, Simplified analytical models for service life prediction of a vacuum insulation panel, Proceedings of the 8th International Vacuum Insulation Symposium, 2007, ZAEBayern/UniWue, Würzburg, September 18-19, Va-Q-tec AG, va-q-vip B Product data, (downloaded ). E. Wegger, B. P. Jelle, E. Sveipe, S. Grynning, R. Baetens and J. V. Thue, "Ageing Effects on Thermal Properties and Service Life of Vacuum Insulation Panels", Accepted for publication in Journal of Building Physics, M. K. Willems, K. Schild and G. Hellinger, Numerical investigation on thermal bridge effects in vacuum insulating elements, Proceedings of the 7th International Vacuum Insulation Symposium, EMPA, Duebendorf, Switzerland, September, 2005, pp ,