VBD - Villes et Bâtiments Durables

Experiments and modeling for the development of Vacuum Insulation Panels applications – EMMA-PIV

Super thermal insulation of buildings by vacuum insulation panels (VIP)

Experiments and Modeling for Multiplication of Applications of Vacuum Insulation Panels

Challenges and objectives

The improvement of the energy efficiency of buildings by renovation is the first approach for reducing greenhouse gas emissions. Interior thermal insulation is hampered by the lack of technically and economically acceptable solutions, because of the amount of work involved for the floors and the loss of living space for the walls. In both cases the use of vacuum insulation panels (VIP), 6 to 10 times better than any traditional insulation, might provide novel and suitable solutions. <br />Building applications also include a very long durability requirement of about 50 years in service. The “EMMA-PIV” project aims to develop a better understanding of the degradation mechanisms that may occur with temperature and humidity. <br />This project addresses two challenges: <br />• Forecasting in real life by modeling the physical phenomena involved in the degradation of the barrier films; <br />• Expanding the range of applications by developing components and panels that can withstand high temperatures and / or humidity. <br /> <br />There are two issues related to the EMMA-PIV project: <br />One energetic and environmental issue because the project targets the development of VIP solutions with performance characteristics that meet the broadening market demands (roofs, exterior insulation, heat production and distribution equipment, heat emitters, etc). The goal is to increase the range of affordable thermal insulation levels to a largest number of applications. <br />Also an industrial and social issue because every progress about the knowledge and the improvement of barrier envelopes will extend the domain of use and the technical possibilities allowing a better control of the performance / cost ratio. <br />

The method used to achieve this was to run in parallel:
• Academic research relating to:
o identify the basic phenomena involved in the mass transfer through the barrier films for VIP (metalized polymeric films); for this the project developed and achieved a specific test program;
o modelling at different scales (barrier envelopes, VIP, system and building) in oder to forecast the performance in real conditions over 50 years;
o understand the degradation mechanisms of the barrier laminates under severe conditions (temperature greater or equal to 50 °C with or without high humidity);

• Applied research to explore one by one the solutions for:
o improved tightness of envelopes,
o and increased resistance to the highest temperatures and humidities that may be encountered in building applications (opaque envelope and energetic systems like exterior insulation, roof, heating components).

For the two major technical tasks that correspond to the two above-mentioned objectives, the work program has been established, the barrier film references have been manufactured and characterizations successfully done.
Regarding the task devoted to the understanding of the transfer phenomena and their modeling the major results are at different scales:
• Envelope Scale: several hypothesis to model gas transfer were considered. All approaches converge and provide a flow 10 times higher than those measured. The options able to explain this difference were analysed.
• Panel Scale: A numerical model of VIP was developed taking into account i) the air and moisture transfer through the complex barriers, and ii) the possible ageing of the core. The VIP ageing is well forecasted.
• System Scale: From the VIP model and using thermal simulation tools at building scale and hydrothermal simulation tools at system scale, the effective conditions incurred by the VIP installed in a building were calculated.

Regarding the task related to the improvement of the barrier envelopes the major results are:
• the degradation phenomena in harsh conditions were identified and linked to the materials used and to the exposure conditions : PET swelling, PET and PU glue hydrolysis, aluminium corrosion, and the delamination of the laminates;
• enhancing solutions were identified and implemented at industrial scale. Two final demos were manufactured which correspond to mild and harsh conditions, and which can estimate the increase of life time at respectively x2 and x10.

The prospects are at several levels: scientific, technical and industrial:
• interpretation of differences between calculation and measurement about film permeance;
• more precise experimental assessment of dry air and steam relative permeabilities thanks to a technique developed at the end of the project, and its inclusion in the models and the product structure;
• improving the knowledge barrier defects in implemented VIPs;
• the establishment of an aging model of the barrier function.

The consortium participated massively in the two international symposia on the insulation vacuum (IVIS 2013 and 2015) becoming clearly the global reference on the subject. Articles in refereed journals and conferences have been published, others are about to be.
Many other benefits are also reportable in standardization (CEN-TC88-WG11) and participation in international activities (annex 65 IEA - EBC).
Two applications for patents and know-how related to EMMA-PIV activity were deposited.

The project "EMMA-PIV" is to ensure and improve the employability of the solution of thermal superinsulation of buildings based on vacuum insulation panels (VIPs). In particular, it deals with the prediction of life in real conditions by modeling the involved physical phenomena and by expanding the application areas currently restricted to low temperatures and low humidity.

Indeed, given the current state of our knowledge, it is difficult to ensure the efficient functioning of the PIV during lifetimes acceptable for the building (50 years) for applications that are stressed, even for short periods, with high temperatures and humidities. This would progress in two directions: the knowledge of mass transfer through the complex barriers, and the increase of the tightness of these complexes even when exposed to severe conditions.

There is a double issue attached to this project.
An energy and environmental issue first, as this project aims to develop solutions PIV reconciling the demands of performance and market demand for applications more varied (insulation of roofs, exterior insulation, insulation wall heaters and heat generation equipment, hot water tanks, transmitters, insulation distribution of hot air or hot water, ...). He can afford to offer high thermal performance of new components that without this contribution could not have been built or renovated at this level.
A major industrial and social issue as well, because any progress in understanding the behavior and improvement of complex barriers will allow the development of the market for PIV, by extending the field of employment (thus favoring mass production) and creating technical leeway to better control the trade-off performance / cost.

The means to achieve this are to run in parallel:
- A basic research on the identification and the modeling of physical phenomena of mass transfer operating in the ultra barriers used as the skin of VIPs, paving the way for the prediction of performance in real conditions of 50 years;
- An industrial research, exploring the possibilities of improving the sealing envelopes and making them more resistant to highest temperature and humidity encountered in building applications (opaque envelope and energy systems).

Project coordinator

Monsieur Bernard YRIEIX (EDF RECHERCHE & DEVELOPPEMENT) – bernard.yrieix@edf.fr

The author of this summary is the project coordinator, who is responsible for the content of this summary. The ANR declines any responsibility as for its contents.

Partner

EMPA Swiss Federal Laboratories for Materials Testing & Research
EDF RECHERCHE & DEVELOPPEMENT
REXOR REXOR
LEPMI / LMOPS Laboratoire d'Electrochimie et de Physico-chimie des Matériaux et des Interfaces
EDF
MICROTHERM MICROTHERM

Help of the ANR 738,553 euros
Beginning and duration of the scientific project: January 2013 - 42 Months

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