10 minutes with…Andrew Dunster and Jorge Corker

Materials World magazine
,
30 Apr 2017

Simon Frost talks to two of the partners in GELCLAD, an EU H2020 project developing a sustainable insulation system based on functional biopolymers and aerogels. 

What is the GELCLAD project?

GELCLAD aims to develop a novel, cost-effective, durable and easy-to-install composite insulation cladding system for buildings, based on an integrated façade panel element with excellent insulation properties. The panels are made from a functional biopolymer structural composite framing skin containing wood-polymer composite (WPC). This, together with an advanced foamable extrudable aerogel core, engineered using a co-extrusion/injection technology, enables the industrial production of a single integrated product with both insulating and weatherproofing capabilities.

The project focuses on using a low energy consumption aerogel acting with an ambient temperature production technology. The composite skin profile will be centred on the combination of natural fibres, along with bioplastics based on lignin-based resins or recycled polymers, such as rPVC, to substitute the oil derived polymers commonly used in WPC systems.

By replacing synthetic polymers with by-product lignin resins derived from the pulp and paper industry and other renewable polymers, we believe that GELCLAD has the potential to create a new product frame made with 100% natural polymers (ecoWPC). Finally, GELCLAD is being designed to be durable and easily demounted, reused and recycled at the end of its service life, reinforcing its sustainability profile.

How developed is the technology?

The project is in its early stages, but some laboratory prototypes have already been developed. At the end of the project in 2019, pre-commercial trials will be carried out to test GELCLAD prototype products. A full-scale prototype demonstration will be performed in demo buildings. Full technical compliance and lifecycle assessment programmes will also help with commercialisation and market entry. We hope that these studies will also provide valuable insights for institutions such as the European Committee for Standardization, the European Organisation for Technical Assessment, other ongoing H2020 projects and promoting the framework and outcomes of the EU’s Energy-efficient Buildings Public-Private Partnership.

Who is involved?

A non-profit association for technology transfer, Instituto Pedro Nunes, Portugal, is coordinating the GELCLAD project, involving universities, research and technology organisations and companies from Portugal, Germany, Slovenia, Spain and the UK. 

What are the properties of the biopolymer composite? 

The functional biopolymer forms the external structural part of the panel, which gives physical and weather protection, and will include functional additives and bioplastics to achieve aesthetic appearance, low environmental impact and thermal insulation, together with essential fire and moisture resistance. The thermal performance is associated with the highly insulating phases in the biopolymer composite and insulating layer. We expect the product to achieve these functionalities while being more sustainable than oil-derived polymers through the use of biopolymers within a WPC.

And the aerogel?

These are made by a sol-gel chemistry process where, firstly, a sol solution is prepared by the hydrolysis and condensation of a precursor in a solvent that becomes a gel through polycondensation reactions. The constituent materials, namely the precursors (alkoxide family) and surface modifiers to generate this gel are becoming available on mass scale. Finally, the liquid phase is removed from the gel structure upon drying before obtaining the final aerogel material. In GELCLAD, this last step will be achieved in ambient pressure drying conditions, allowing for a more affordable, easier and more sustainable production. This complex process results in an extraordinary physical and chemical structure with remarkable insulating properties. 

Aerogels are synthetic solid network materials with a very low density (as low as 1kg/m3) and porosity levels up to 99%, mostly in the nanoscale range. Apart from outstanding thermal conductivities that can be as low as 13mW/mK, aerogels can also present other valuable properties for building applications, such as fire resistance, high hydrophobicity and longevity.

How could GELCLAD make energy savings of 40% or more? 

The improvement in thermal insulation provided by the materials within the ecoWPC skin, and especially the aerogel core, will make the GELCLAD system extremely thermally efficient. Based on advanced nanotechnologies, the superinsulation aerogel will aim to be a key element of the GELCLAD solution. This foam-like aerogel is expected to exceed the performance of current state-of-the-art insulation materials commonly used for similar applications (fibre insulation and polymeric foams such as mineral wool, PU, EPS, etc) by around 45%, meaning that it will easily meet the superior insulation requirements of the latest nearly-zero-energy buildings thresholds. Moreover, the composite outer skin material will be optimised towards low moisture absorption, fire resistance, dimension stability and low density, all contributing to the overall value of the solution.

What makes GELCLAD less labour intensive than alternative systems?

One of the GELCLAD project goals is to address market needs for a practical answer to faster and easier retrofit on-site to upgrade the appearance and energy performance of existing buildings. We are designing the product to be an easy-to-install single multifunctional construction panel system, producing weather protection, ventilation and external insulation. This will allow the replacement of traditional labour-intensive external insulation systems currently available, such as ventilated façade frames, external thermal insulation composite systems and standard cladding profiles. These require several products to be set up together on site to achieve the required performance. We expect the ease of installation of GELCLAD will be unmatchable compared with traditional solutions, being a truly modular product, with standard joints and connections systems and being easy to cut, mounted and fixed on-site with standard tools, as well as having good mechanical properties and being totally compatible with the majority of building and material combinations.

What is the commercial aim of the project? 

Our overall objective is to create, demonstrate and validate an affordable and efficient smart cladding eco-panel solution that can meet energy efficiency requirements. It will maximise living space by delivering the insulation from the outside of the building, and could also provide some sound insulation. The primary entrance market of GELCLAD will be for the retrofitting of urban residential buildings, but we envisage that the panel could also be used for new buildings, especially those related to lightweight construction and nearly-zero-energy buildings. The total wall areas of the European residential building stock is currently estimated to be around 12,600 million m2 for houses and 4,450 million m2 for high-rise buildings. Under this context, adding insulation will be relevant for 40–60% of the building stock during the next 10 years, which represents a huge market. Meanwhile, many old buildings, mostly from the 1960s–80s, could benefit greatly from energy savings for their residents.

Dr Andrew Dunster FIMMM is Principal Consultant (Materials) for BRE, UK.

Jorge Corker is Senior Researcher in Materials at Instituto Pedro Nunes, Portugal.