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Report

Teaser, summary, work performed and final results

Periodic Reporting for period 1 - INNOVIP (Innovative multi-functional Vacuum-Insulation-Panels (VIPs) for use in the building sector)

Teaser

Summary

Effective insulation systems in buildings are key to optimizing their energy performance. Vacuum insulation panels, or VIPs, are an extremely effective and space-saving solution. Currently, vacuum insulation panels generally comprise a core of pressed pyrogenic silica or mineral fibres. Using a new type of protective envelope and alternative fillers â€“ for example ground perlite â€“ the INNOVIP consortium aims to enhance the competitiveness of this highly-efficient solution. Specifically, the following goals are planned to achieve:

- improve the thermal performance by at least 25%
- achieve a minimum standardised service life of 25 years with minimum deterioration
- develop an innovative production process incorporating simplified wrapping procedures, and through this to reduce manufacturing costs by 20% compared with those of conventional vacuum insulation panels.
- reduce insulation material costs by around 30% compared to established vacuum insulation systems and conventional insulating materials (based on the cost per square metre of thermally equivalent insulation systems).
- provide additional functionality and durability including resistance to deleterious effects such as mould growth.

Modern VIPs are already very efficient, but this performance can be lost over a period of years. The reason for this an increase in internal pressure, caused by the slow penetration of air and humidity into the vacuum elements. This causes their thermal conductivity to increase, which means that insulation decreases. The new design for the envelopes should have at least 40% lower permeability for water vapour and air and thus guarantee good insulation performance for up to 50 years. By combining several production steps, the labour-intensive wrapping of prefabricated core material with envelopes can be considerably simplified. The use of a loose pyrogenic silica powder permits a lower density for the filler compared to compressed panels, which leads to a saving in materials and production costs. Furthermore, the lower density reduces thermal conduction in the core.

Through the improvements in the envelopes, it will also be possible to use much less expensive core materials than pyrogenic silica. In the research project, expanded perlite powder is being examined as an alternative. This has significantly larger pores, which, due to the increased number density in the larger spaces, requires a higher vacuum in the panels and thus places higher requirements on the envelope. While vacuum panels with perlite, also called volcanic glass, do display thermal conductivity properties that are around one third higher than those with a silica core, they are significantly less expensive to produce. The lifetime of perlite-based panels can be extended to 50 years by using a small quantity of desiccant.

Overall, the manufacturing cost of VIPs will be reduced by 30% through the innovations in the core materials, envelopes and production processes. For applications where very thin insulation panels are not necessarily required the even less expensive alternatives with perlite cores can be used. Even the further enhanced envelopes are more cost-effective than those previously used. Added to this is the much accelerated manufacturing process, thanks to the new technology, which is likewise contributing to the cost reduction.

Work performed

While the edge design is already completed with Milestone 6, other design principles are still under investigation. Additional functions which can be achieved by nano-coatings applied to the already selected cover layers are specified at lab scale to achieve Milestone 7 but the selection of coating formulations which will be used for different types of applications has not been done definitively. Another point under development is the improved durability of envelope foils and the resulting bag design.

The use of lighter fumed silica loose powder core inside the cardboard boxes and an adapted amount of the IR-opacifier leads to values of lower than 0.004 W/(mâˆ™K), which is a big success for the very first production batch of panels.

As the new high barrier laminates are still under development (WP 2) and the artificial ageing procedure is very time consuming, no final results are available at this stage of the project.

The cardboard box solution allows a density reduction, accompanying less material used, resulting in a huge cost reduction. Exact values are not available yet as the production expenses can only be estimated after the first automated production series. For the perlite panels the cardboard solution will be applied as well whereas a higher thickness is required to reach approximately the same performance. Despite the higher amount of perlite powder needed the price will even be much lower.

Currently under investigation in the scope of WP 2 are the EVOH-approach and the PST-technology. While the EVOH is facing its biggest challenge in the durability of the moisture barrier function, the PST technology searches for a solution towards air permeation barrier properties.

In the scope of WP 5 LCC and LCA calculations are conducted. A workshop for active projects in the AMANAC cluster took place to discuss the lack of data for reasonable LCA analysis and possible solutions. As input for the LCA energy cost savings will be modelled with dynamic building simulation and the definition of suitable models for the thermal modelling has been started.

Final results

Compared to State-of-the-Art VIP, the cost will be reduced by at least 25% using silica-loose fill of lower density as core material (instead of boards) together with a less elaborated manual production. The cost can be reduced by at least 45%, using perlite granules as loose fill. Current state of the work shows, that it is feasible to reach this cost reduction at the end of the project, leading to much higher sales figures due to significantly increased numbers of panels sold.

Compared to silica boards, the silica loose-fill core material has a lower density (15%) and therefore a 10%-15% better thermal performance. Additional 10% improvement in thermal performance will be gained at the component level from reduced thermal bridging at edges and mechanical fasteners. This challenge could already be reached by the first prototype production with loose fill silica, showing 20 to 25 % better thermal performance at the center of panel alone.

Long-term performance will be improved by 20% with the proposed concepts on the envelopes. First results on the new components (foils and core) show that this ambitious goal is in reach, but additional techniques might be necessary (e.g. PST solution in WP 2 instead of the EVOH approach). Artificial ageing tests will be performed at the second period of the project on real pilot products.

By reducing the density of the silica core material and/or using perlite as alternative core material, it will be possible to reduce the embodied energy by at least 25%. Together with the better durability and longer service life and the improved insulating properties, a reduction of the energy spent during the whole life cycle of building by 15%â€“ 20% will be achieved. A density reduction for silica powder is directly related to the reduction of embodied energy of the core material. First recycling trials show fully recycled plastic materials from the envelopes and very promising results for the thermal performance of recycled silica powder.