Final Report Summary - AEROCOINS (Aerogel-Based Composite/Hybrid Nanomaterials for Cost-Effective Building Super-Insulation Systems)
Executive Summary:
In the context of global climate control policies, improving the energy efficiency of existing buildings represents a great challenge, worldwide as well as at the European level. Reducing the energy consumption of buildings is nowadays preferably achieved by increasing the thermal resistance of the insulation layer in the building envelope.
The AEROCOINs project, in order to contribute to the future reduction of energy consumption by decreasing heating and cooling demands of existing-buildings, has been working on the clever combination of sol-gel science and nanotechnology aiming to advance on the design and development of novel super-insulating aerogels.
The AEROCOINs project has developed new reinforcement strategies in order to produce mechanically strong super-insulating aerogel composite/hybrid materials. The main approaches developed are based on the employment of two polysaccharides materials: cellulose and pectin, respectively. These strategies open new possibilities for further development of superinsulating materials.
It was found in this project that the critical stress point when wet gels crack during Ambient Pressure Drying (APD) can be found by measuring the internal pressure evolution. This valuable information can be used to reduce the drying rate before the crack develops. In the current state-of-the art it is commonly assumed that this point roughly corresponds to transition from the constant to the falling rate period, which requires sample mass monitoring in situ.
For the thermal characterization of this type of highly insulating materials, an optimized hot-wire method has been developed within AEROCOINs, which permits the characterization of very small samples (down to diameters of about 27 mm). This method has been validated by comparing it to measurement with the same set-up on larger samples and comparing it to hot-plate results.
In addition, an efficient ambient pressure drying process and optimization on the supercritical drying process have allowed the up-scaling manufacture of aerogel boards. Designing and fabricating a novel building component prototype based on the developed aerogel-like material has yield a component compatible with conventional construction installations where the envelope is part of the buildings. This building component integrates low-conductive plastic-composite profiles and plasterboard renders within a multi-layer arrangement, and it has obtained the best fire classification for organic materials: B-s1,d0.
Demonstration of the structural, mechanical and thermal performance of the insulating component under real conditions have been performed in two demo buildings (in the DemoPark in Madrid and KUBIK in Bilbao) and compared with conventional insulating materials.
Project Context and Objectives:
World energy demand is expected to increase by up to 71% between 2003 and 2030. As it is defined by the International Energy Agency (IEA) the energy future demand has to be a balance between the “three Es”: Environmental protection, Energy security and Economic growth. Different researches have indeed concluded that the only way to avoid a drastic increase of energy consumption is to achieve an order-of-magnitude improvement in Energy-Efficiency (EE), defined as the ratio between energy services provided and energy consumed.
According to the Buildings Performance Institute Europe (BPIE) the residential stock in Europe is the biggest segment with a floor space of 75% of the building stock and accounts for the 68% of the total final energy use in buildings . Space heating is the most energy intensive end-use in homes accounting for 70% of the total final energy use. This is due to the fact that more than 40% of the European residential buildings were constructed before the 1960s, when energy building regulations were very limited, and have not undergone renovations to improve energy performance, meaning that, these have low insulation levels and their systems are old and inefficient. One approach to improve energy efficiency of buildings is to enhance the thermal resistance of the envelope.
The development of advanced insulation technologies for energy efficient buildings is a very promising field. Indeed, the emerging field of superinsulating materials for new and retrofitting buildings, thanks to nanotechnology, has great promise to contribute to this unique domain of sustainable development.
Based on the “global” assessment that silica is the ideal raw material for large-scale commercial insulation application for buildings, the present project restricts its research area on a well-defined selection of improvement strategies for the silica-based aerogel composite/hybrid systems. The central goal is to capitalize on partners’ expertise and their deep knowledge of the state-of-the-art described in the literature by finding new and/or complimentary ways to manufacture superinsulating and strong very efficient aerogel-like materials.
The main goal of the AEROCOINs project was to develop a new composite/hybrid aerogel material to improve the insulating performance of existing buildings aiming at reducing their energy demands. Hence, the main objectives were:
OG1.- to synthesize and elaborate novel, mechanically strong and superinsulating aerogel-based materials via a subcritical ambient drying process.
OG2.- to design and fabricate a highly efficient and robust building component (based on the developed aerogel composite and/or hybrid material) for its implementation in the external part of the envelope of existing buildings.
OG3.- to demonstrate the significant cost reduction of the commercial production of superinsulating aerogel-like materials and hence also of the component.
These general objectives were expected to be achieved through the development and completion of complementary work packages. These, were based on the following specific scientific and technical objectives:
S&T O - Related to the elaboration and development of a composite/hybrid aerogel material.
1. To obtain a reinforced aerogel-based superinsulator material: improvement of mechanical properties (an improvement of up to 100 times versus plain silica aerogel) while maintaining thermal conductivity at a very low level (λ< 0.018Wm-1K-1) by cross-linking and/or nanodispersion concepts.
2. To promote multifunctionality of the so-obtained superinsulating materials: for example, enhancement of flame retardancy with mineral nanodispersion in the sol.
3. To develop a subcritical ambient drying process: minimize evaporation-induced shrinkage thanks to an optimized fine-coupling between sylilation chemistry of the silica network and strengthening techniques (cross-linking and nanodispersion).
S&T O – Related to the design and development of the insulation façade construction component.
4. To transfer the chemical process technology of best candidate lab-scale materials to the pilot scale (including both, the synthesis and ambient pressure drying processes for the elaboration of large monolithic superinsulating boards of 50 x 50 x 1 cm3 dimensions.
5. To design and fabricate a brand-new building component prototype based on the developed aerogel-like material, which will need to be compatible with conventional construction installations for implementation into the envelope part of buildings.
6. To design a cost-effective continuous industrial-level process for the production of the aerogel-like material board.
S&T O – Related to the validation of the efficiency of the insulation façade component and building integration.
7. To demonstrate the thermal performance of the highly insulating component under real conditions.
8. To demonstrate the structural and mechanical performance of the insulating component under real conditions.
To accomplish its objectives, the AEROCOINs project was structured into seven workpackages (WP), five of which address specific technical objectives (WP1-WP5), one of them is devoted to dissemination and exploitation issues (WP6) and the last one to management activities (WP7).
The seven WPs were the following:
The WP1- Synthesis of reinforced superinsulating aerogels was focused on the design and synthesis of brand new superinsulating silica-based aerogels. The main technical and scientific objective of WP1 has been to optimize the soft-chemistry processes for the preparation of such superinsulating silica-based aerogel-like materials i) to promote their mechanical reinforcement and ii) their multifunctionality, without degrading their very low thermal conductivity.
The WP2 - Drying and thermal conductivity optimization dealt with the development and optimization of a robust and efficient drying process to be transferred at pilot scale (in WP3) for elaboration of strong superinsulating aerogel-like boards. The main technical objective of WP2 was to develop an effective lab-scale subcritical ambient pressure drying (SAPD) process i) able to minimize shrinkage and cracking during evaporation, ii) permitting to obtain 10cm×10cm×1cm monolithic aerogel plates and iii) well-suited for further transfer to pilot scale. WP2 also aimed at adapting standard supercritical drying (SCD) process to the specificities of the brand new organic/inorganic gels synthesized within WP1. Because of its higher degree of maturity, the SCD route would provide the so-called “plates of reference”.
The WP3- Pilot scale material fabrication focused on the design and fabrication of new superinsulating aerogel board (of 50cm×50cm×1cm dimensions). The 3 main technical objectives of WP3 were i) up-scaling of optimized materials (at least one solution chosen from WP1-WP2), ii) to produce sufficient amounts of the selected best-case aerogel boards for the component manufacture in WP4 and iii) to perform an analysis of the potential for up-scaling and large-scale industrial fabrication of the aerogel boards. This included the design of a continuous fabrication scheme and a complete volume and parameter dependent cost estimation.
The WP4- Aerogel-based component manufacturing dealt with the design and fabrication of new superinsulating building components for retrofitting installations. The main technical objective of WP4 has been the customization of individual aerogel boards to yield a component which is compliant with current insulating systems and solutions and can be used directly in construction.
The WP5- Building integration and validation dealt with energy efficiency demonstration activities and its main objective was the integration of the component (obtained in WP4) in a demonstrator building to validate its thermal, mechanical and structural performance under real conditions.
The WP6-Dissemination and exploitation aimed at finely studying the global impact of the developed superinsulating silica-based aerogel-like materials for improving energy efficiency in buildings and to set up the academic/industrial dissemination and exploitation strategies of the outputs of the project.
Finally, the WP7-Project Management had as a main objective to ensure a sound coordination and management of the project covering administrative, legal and financial issues, and the relation with the EC.
Project Results:
The main scientific and technical results of AEROCOINs project are described in this section. They can be divided in the following categories:
1. Developments on the sol-gel chemistry in order to prepare reinforced silica-based aerogel materials.
2. Characterization of Aerogel materials.
3. Development of the up-scaling process for the fabrication of aerogel material.
4. Life cycle analysis of aerogel materials.
5. Aerogel-based building component design and evaluation.
1. DEVELOPMENTS ON THE SOL-GEL CHEMISTRY IN ORDER TO PREPARE REINFORCED SILICA-BASED AEROGEL MATERIALS
Different chemical strategies have been pursued for the reinforcement of silica aerogels, based on crosslinking and nanodispersion approaches. Herein, the main achievements are described.
New strong polysaccharide and polysaccharide-silica aerogels have been developed within AEROCOINs. Two polysaccharides were used for this purpose: cellulose and pectin. Silica sol was polyethoxydisiloxane (PEDS), a product from PCAS.
Cellulose-based aerogels
a) New experimental set-up for accelerating the impregnation of silica sol into cellulose matrix, and strong cellulose-silica aerogels have been developed by ARMINES
Strong, light (bulk density around 0.2 g/cm3) and monolithic crack-free cellulose-silica composite aerogels have been prepared by impregnation of wet coagulated cellulose with PEDS-based solution. The impregnation was performed either by molecular diffusion or by a forced flow process (due to a pressure gradient). The latter allowed an enormous decrease in the impregnation times, by almost three orders of magnitude. In both cases, nanostructured silica gel was in situ formed inside cellulose matrix porosity.
Nitrogen (N2) adsorption analysis revealed an almost threefold increase in specific surface area, from cellulose aerogel alone to their organic-inorganic composite counterparts. Thermal conductivity of composite aerogels was lower than that of cellulose aerogel due to the formation of mesoporous silica inside cellulose pores. Composite aerogels were strongly reinforced as compared with the reference aerogels still keeping high ductility characteristic of Aerocellulose (i.e. pure cellulose aerogels): Young modulus increased by 3-4 times and fracture strain remained very high, about 60%.
b) Thermal super-insulating hydrophobic and monolithic cellulose-silica aerogels
Hydrophobic cellulose-based aerogels and their organic-inorganic counterparts were synthesized and characterized by ARMINES. Cellulose was chemically modified with triphenylmethyl chloride in homogeneous conditions; composite aerogels were prepared by impregnation of coagulated tritylcellulose by PEDS which was then in situ gelled in the porous cellulosic matrix (Figure 1). Silica phase was subsequently hydrophobised with HMDZ (hexamethydisilazane) and composite samples were dried with supercritical CO2.
The impregnation approach and hydrophobization of both phases resulted in new organic-inorganic monolithic thermal super-insulating aerogels with the thermal conductivity significantly below that of air at ambient conditions, 0.021-0.022 Wm-1K-1, and good resistance (in weight and volume) towards humidity in the conditions studied (at 30°C and 80%RH for 24 hours). The obtained organic-inorganic aerogels are finely nanostructured, with very high specific surface area (between 600 and 800 m2/g depending on synthesis parameters), and highly hydrophobic, with water contact angles 133-135°. Tritylcellulose aerogels are highly compressible, with zero Poisson’s ratio. The mechanical properties of composite organic-inorganic aerogels are strongly improved as compared with pure silica aerogels.
c) Nanofibrillated cellulose dispersion route
Compounding of PEDS gels with unmodified, maleic anhydride esterified and TEMPO oxidized NFC works in principle, yielding monoliths via supercritical drying; mechanical reinforcement in compression is nonexistent but in tension there is a 50% improvement.
Figure 2. .Cellulose-silica aerogels prepared from nanofibrillated cellulose (EMPA)
d) Cellulose foams route
Since a poor dispersion of the cellulosic fibers in silica sol was observed, an alternative route was developed by EMPA for compounding of PEDS gels with unmodified and silylated modified NFC foams. The approach uses freeze drying of nanofibrillated cellulose in presence of MTMS. The E-modulus of the composites increased, but fracture toughness remained the same or was slightly lowered. Thermal conductivity values were around 0.016 W/(m K) at room condition for the composites reinforced with the MTMS modified foams, while values significantly higher (0.018-0.020 W/(m K)) were obtained for silica reinforced with the unmodified foams.
Figure 3. Cellulose-silica aerogels reinforced with silylated NFC foams (EMPA)
Pectin-based aerogels
Pectin based aerogels can be obtained applying crosslinking and nanodispersion approaches:
e-1) 100% pectin strong and monolithic thermal super-insulating aerogels via cross-linking
Pectin-based aerogels were synthesised via cross-linking of pectin with Ca2+ by ARMINES. Finely nanostructured Aeropectins with extremely low densities (0.02 – 0.06 g/cm3) were thus obtained, showing high specific surface areas (200-300 m2.g-1). Such Aeropectins are able to sustain up to 80-90% strain without breaking. The associated thermal conductivity is remarkably low, 0.015-0.023 W/(m.K) at room conditions (Figure 2). This fully biobased aerogel is thus completely falling in the range of true thermal super-insulating materials.
e-2) Pectin route via nanodispersion
In the nanodispersion approach pectin biopolymer has also been employed. Using one-pot mixing of dissolved pectin with sodium silicate, monolithic pectin-silica aerogels with super-insulating properties could be obtained via SCD; the thermal conductivity values of the resulting composites range from 0.016-0.022 W/(m K).
Figure 5. ‘One-pot’ pectin-silica aerogels designed by EMPA &ARMINES
f) Super-insulating pectin-silica aerogels.
Pectin-silica composite aerogels were prepared via impregnation of pectin matrix, using the same approach as developed for cellulose-silica composite aerogels. Hereby the silica phase was hydrophobized. Higher density as compared to the neat Aeropectin (0.10 – 0.15 g/cm3), and huge specific surface area (800-850 m2.g-1) were obtained. Pectin-silica aerogels were also super-insulating with the conductivity 0.015-0.023 W/(m.K) (Figure 5). The contact angle with water was around 135° and humidity uptake was strongly decreased as compared to neat Aeropectin at the same conditions.
2. CHARACTERIZATION of AEROGEL MATERIALS
Several characterization tools have been employed for the characterization of the developed aerogel materials and also for optimizing the synthesis strategies in reducing the thermal conductivity of silica aerogel based composites on one hand and improving their mechanical properties for handling and application on the other hand.
For the thermal characterization of this type of highly insulating materials, an optimized hot-wire method has been developed by ZAE within AEROCOINs, which permits the characterization of very small samples (down to diameters of about 27 mm). This method has been validated by comparing it to results derived with the same set-up on larger samples and comparing it to hot-plate results.
Structural and mechanical characterization was performed to provide first trends in terms of the two contributions, solid and gas phase thermal transport to the overall thermal conductivity (see Figure 6). After a cross validation of the methods with lab scale samples provided by the AEROCOINs partners, aerogel samples were analyzed with respect to their thermal properties at ambient conditions as well to their Young’s moduli.
Figure 6: The measurement of the Young’s modulus and the specific BET-surface area (pore size) provide quantities that allow for an identification of trends in terms of contributions to the total thermal conductivity to be expected. The later can also be measured at ambient conditions representing a superposition of the solid phase and the gas phase contribution. The two effects can be separated by measuring the gas pressure dependence of the thermal conductivity (p), with (p0)= solid.
The evaluation of the thermal conductivity of some aerogels reinforced with vinyl polymers (prepared by TEC) reveals that the thermal conductivities as determined at ambient conditions decrease with density down to about a density of about 150 kg/m3 and then saturate at 0.013 to 0.014 W/m K. In other cases, i.e. some aerocellulose-based aerogels, high thermal conductivities are obtained due to a combination of a high heat transport along the solid phase and a large fraction of macropores also present in the composites.
In general, for the nanofibrillated cellulose based aerogels the incorporation of individual NFC fibres into the aerogels yielded materials with poorer or equivalent mechanical properties; the elastic modulus was observed to decrease slightly, while no change was observed in the compressive strengths. However, the tensile properties were observed to increase by about 50 % with the addition of lower concentrations of NFC. The presence of the fibres does not affect the thermal conductivities of the aerogels or increased them slightly.
In the case of Cellulose foams route combined with supercritical drying, the presence of unmodified NFC foams within the silica aerogel caused a deterioration of the mechanical properties, as exemplified by the gradual decrease in elastic modulus (E), compressive strength and fracture strain with increasing NFC mass fraction. A significant improvement of mechanical properties is observed when the silica is interpenetrated with silylated NFC foams. In comparison with the reference silica aerogel, these composites display a maximum increase in E of 55 %. All composites displayed thermal conductivities of 0,020 W/m·K or less which makes them superinsulating materials.
For the supercritical dried pectin based aerogels, in general, the elastic modulus (E), compressive strength and fracture strain strongly depend on pectin loading and pH fabrication value. The most significant improvement of the optimized composite displayed an increase in E, final compressive strength and fracture strain of 9.4 MPa/ 27.5 MPa/ >80%. All composites displayed thermal conductivity values below 0.017Wm-1K-1 which shows that they are true superinsulating materials.
Figure 7. (a) Strain-stress curve (b) Thermal conductivity (c) Compressive strength and (d) E modulus of the supercritical dried NFC foam reinforced PEDS-P750E20 aerogels synthesized at different pH values.
3. DEVELOPMENT OF THE UP-SCALING PROCESS FOR THE FABRICATION OF AEROGEL MATERIAL
An ambient pressure drying process (EMPA) has been developed and applied in the manufacturing of aerogel boards in AEROCOINs. The reactors were constructed from corrosion resistant (HCl) grade stainless steel and are designed for 22 samples of 50×50×2 cm³ per batch. The main steps for the fabrication of the boards are as follows:
Stage 1: Sol-gel process: In a first step, lab-scale recipes were adjusted to the large scale reactors and the gelation and aging processes optimized. In a typical batch, 190 liters of the sol with 30% of the PEDS-P75E20 precursor content (55.1L) was stirred with ammonia and then transferred into the gelation reactor.
Stage 2: Gelation and aging process of the aerogel composites: After keeping sols at 55oC for 2 hours, the gelation and aging proceeded simultaneously and the hydrogel blocks were lifted for checking the strength and removing the extra gels between plates.
Stage 3: Hydrophobization process of the aerogel composites. After aging, the hydrophobization of the gels is initiated by using HMDSO (the HMDSO can be recycled for next batches use) with catalytic amount HCl/Ethanol solution for 15 hours.
Stage 4: Ambient drying of the aerogel composites: After hydrophobizaton, the gels are dried employing the drying profile: 3 hours at 150°C.
Figure 8. Fabrication of ambient pressure drying of the prototype board of aerogel: (A) the hydrogels moved out of the aging container (B) wet gels moved to modification reactor (C) silylated gels take out from modification (D) aerogels after drying.
4. LIFE CYCLE ANALYSIS (LCA) OF AEROGEL MATERIALS
An LCA assessment for the production of silica aerogel insulation has been developed and compared with conventional insulation materials made from oil or mineral bases.
Life cycle analysis has been performed for two silica aerogel production routes: for ambient drying and for supercritical drying processes, respectively. (Even if the scope of AEROCOINs was the development of ambient drying process, supercritical drying has also been employed).
The LCA assessment is made according to the basic principles of LCA methodology (ISO 14040/14044). The main goal was to use the data from European Life Cycle database (ELCD) but due to the limitation of this database, the LCA has taken also existing literature data.
The assessment covers also some variation in raw-material routes and electricity production method. Normally the life cycle of a product assessment covers all the phases of the product life but as this is a novel product and thus its environmental impact size is not known, only production phase (A1 – A3) and global warming potential (GWP) is taken into consideration. Thus the assessment covers life cycle stages from “cradle to factory gate” including information from raw material supply, transportations, manufacturing of products and all upstream processes.
Total GWP for aerogel life cycle stages A1 - A3: GWP impacts for the aerogel life cycle stages A1 – A3 (raw material acquisition, transportation and production) calculated per 0.11 m3 aerogel board for ambient drying- and 0.06 m3 for the supercritical product. The result is shown in Table 1,
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Table 1. GWP results for the aerogel production (0.11 m3). Electricity, which used in production process, has low GWP (140 g/kWh). Production life cycles are: raw-materials (A1), raw material transportation (A2) and aerogel production (A3). A1 considers that virgin HDMSO is used by 7 % and virgin ethanol is used by 2%.
A1
kg CO2e A2
kg CO2e A3, low
kg CO2e Total,
A1-A3, low
kg CO2e Relative impact, %
Sol gel preparation 50 9.5 0.74 60 52 %
Gelation and aging 5 0.0063 0.71 5.2 5 %
Hydrophobization 33 0.33 2.0 35 31 %
Ambient drying 13 13 12 %
Total, kg/0.11 m3 aerogel 88 9.9 17 114 100 %
Total, kg/kg aerogel 7.3 0.82 1.4 9.5 100 %
Table 2. GWP results for the supercritical aerogel production (batch size 0.06 m3). Electricity, which used in production process, has low GWP (140 g/kWh). Life cycles are: raw-materials (A1), raw material transportation (A2) and aerogel production (A3). A1 considers that ethanol and isopropanol is recycled and only 1% of virgin substance is used.
A1
kg CO2e A2
kg CO2e A3, low
kg CO2e Total,
A1-A3, low
kg CO2e Relative impact, %
Sol gel preparation 22 4.2 26.2 31%
Gelation and aging 3.1 0.93 3.2 5%
Hydrophobization 2.8 0.0018 2.8 3%
Total for production 50.6 50.6 61%
Total, kg/0.06 m3 supercritical aerogel 28 5.1 51 83.3 100%
Total, kg/kg supercritical aerogel 4.2 0.78 7.7 12.6 100%
Figure 9. GWP share for Aerogel life cycle A1-A3.respectively for ambient drying and supercrithical drying product. Electricity used in production produced with low GWP.
The assessment is also made for the aerogel use. The GWP result is compared on the level of building components with alternative insulation solutions (building components with traditional insulation materials with the same performance and for the case of renovation with 100 mm additional aerogel in Northern or Southern Europe use). Figure 8 shows the example of energy saving, which is presented for one analysed case.
Figure 10. Annual heat losses and savings compared to the 100 mm mineral wool insulation, cases Finland and Spain.
5. AEROGEL BASED BUILDING COMPONENT DESIGN AND EVALUATION
A building integration framework has been generated, as it is directly linked with the format in which the material/building component is available. The defined integration framework targeted at internal insulation systems for building retrofitting, as this application provided the most suitable environment for the competitive advantage of superinsulation: reduced use of space in locations with space constraints.
Several alternatives were discussed, and integration of laminated aerogel boards in plasterboard based solutions was approached. However, when manufacture tests were conducted with up-scaled aerogel processes, this solution was evaluated inadequate for full-scale deployment, and an alternative building component was proposed. This finally developed building component integrates all the elements needed for the building integration of aerogel boards, as it incorporates all the elements previously defined as part of the construction system for building integration. The final version of the prototype consists of: 2 aerogel boards closed between two polymeric profiles and covered on one side by the reflexive cover and on the other side by the plaster board (Figure 11).
Figure 11. Prototype selected for the further studies
In AEROCOINS, a novel approach has been provided to the use of structural reinforcement profiles for internal insulation systems. State of the art dry internal insulation systems rely on metal or wooden profiles/studs to mechanically bear the system and render. Along the project, it was realized that these solutions tend to produce relevant thermal bridge effects (above 30% reduction of insulation capacity) when used in highly insulated façades, and traditional solutions are not applicable when highly insulating materials such as aerogels are used. Therefore, TEC has applied plastic composite based solutions which provide a high performing solution to this problem.
The moisture performance was also evaluated as relevant. This issue was approached through the evaluation under typical construction environments by VTT, where assessments in typical building applications under cold and warm climate conditions were performed. The moisture performance principles, required protection means against moisture loads and the moisture risks in the aerogel applications were studied. Only the performance of AEROCOINs aerogel materials were studied, other materials were assumed to have safe moisture performance in the presented assembly.
Example of simulation performance is presented in Figure 12. In this simulation performance in Malaga (south Spain) was examined in undamaged composite. Also effects of different structure and small damages were investigated both in Finland and Spanish climatic conditions.
Figure 12. Simulation of relative humidity values for the exterior (ext) and interior (int) surfaces of aerogel thermal insulation under Malaga climate (south Spain).
To verify used parameters in simulations also experimental investigation was performed. In these test the aerogel component was subjected to different moisture loadings and moisture behaviour was followed. Example of these tests is presented in Figure 13. In the test, component is subjected to 95%RH moisture. In the test, a moisture barrier prevents moisture accumulation. Even small nail or drill hole did not cause dramatic weakening in moisture behaviour.
Figure 13. Panel interior humidity when subjected to high relative humidity in moisture barrier side.
According to simulations and measurements the moisture damage risks were higher in cold northern climate than in warm climate conditions. This is due to the higher temperature and partial vapour pressure gradients in structures and the also the lower drying capacity of the structures under cold conditions. These differences set also different requirements for the protection of aerogel insulation layer under different climate loads, something to be considered for further designs of aerogel-based materials.
On the other hand, concerning the fire retardant properties of this type of materials, indicative Single Burning Item (SBI) test and inflammability test were performed by TEC. Organic modified silica-based aerogels developed in AEROCOINs ignited very quickly as soon as the burner was on. Hence, the peak of the heat release was very high. Once the organic part burns, the inorganic part starts to fall down. This phenomenon should be considered the final of the test (according to EN13823 standard and an E classification would be declared). The sample did not ignite neither propagate after the application of the flame. However, the building component based on the aerogel materials has obtained the best fire classification for organic materials: B-s1,d0.
AEROCOINs has evaluated the performance of aerogel materials in two demo buildings, KUBIK in Bilbao by TEC and DemoPark in Madrid by ACC, respectively. Test set-ups were constructed and monitorization campaigns performed over roughly 6 months where the overall thermal and mechanical performance of building components was evaluated. Results from demonstration reached the performance obtained at laboratory scale, and that in all cases superinsulated assemblies were obtained.
Figure 14. Left: External view of the test set-up for Aerocoins at the Kubik test facility in Bilbao (Spain). Right: DemoPark in Madrid, Spain.
Potential Impact:
The DISSEMINATION EFFORTS undertaken within the AEROCOINs project were aimed at communicating and disseminating the relevance and importance of super-insulating materials aerogels, mainly for the building application. Over last years, the European Commission has boosted innovative measures to improve Europe´s energy efficiency and to contribute to the objectives 40-27-27 by 2030 . Specific Directives , energy labels and standards for products save money which can partially result in new job creation. Under this context, AEROCOINs has aimed at communicating the developments of high insulation performance aerogel based materials developed within the project.
Dissemination activities were deployed at two levels: consortium/project level as well as by individual project partners using their own dissemination channels and networking relationships. Below the main dissemination channels and respective activities developed within AEROCOINs are presented.
Project website and mailings:
AEROCOINs project web site (www.aerocoins.eu) was created as a primary source of information about the project activities and its key outputs. Some visual materials that have been presented there include public deliverables, information on relevant events, list of dissemination activities, and list of publications.
Mailings as a dissemination channel were also used. Since the creation of AEROCOINs website it has received a total of 8.023 visitors, with a 72.2% of new visitors and a 27.8% of returning visitors.
Restricted access zone of the web site
To ensure proper dissemination of project outcomes amongst project partners, a restricted access zone was created within AEROCOINs web site. All key documents, restricted deliverables, working presentations, minutes of the meetings have been uploaded for internal consortium use.
Workshops and Conferences:
Two AEROCOINs workshops and a final conference have been organized.
i) 1st AEROCOINS workshop “Superinsulation Aerogel Materials for Energy Efficiency” was organized by ARMINES and TECNALIA on the 19th of June 2012 in Sophia Antipolis (France).
The goal of the workshop was to engage external academic and industrial experts together with Aerocoins partners in scientific and technical discussions and exchanges concerning the opportunities arising from the current demand in Europe for Energy Efficient Materials particularly focused on superinsulating aerogel materials for strategic sectors (building, space, …).
More than 30 persons from Finland, France, Germany, Poland, Portugal, Spain and Switzerland participated to the work-shop. There were about 10 representatives from companies, and also from agencies related to building industry. About 20 participants were from public research laboratories and universities.
The work-shop showed a lot of interest from all players, both at industry and academy levels, involved in the development of efficient insulation materials for building envelopes applications. The presentations were followed by questions and discussions; the exchanges on hot topics continued during lunch and poster presentations.
ii) 2nd AEROCOINs Workshop “High Performance Thermal Insulation (HPI) 2013 - Towards Near Zero Energy Buildings” organized by ZAE and TECNALIA at the Energy Efficiency Center (EEC), ZAE Bayern (Würzburg, Germany) on the 27/28th of November 2013.
The focus of the workshop was specifically more on competitive insulation systems and integration rather than materials synthesis.
In particular, the workshop aimed at bringing together the people in the field of thermal insulation, building physics and architecture to:
• Present recent developments in terms of insulation materials and components suited for building applications;
• Address problems to be solved upon integration and combination of new components towards zero energy buildings;
• Give an overview over current demo-activities;
• Discuss degradation and recycling issues related to next generation buildings.
90 participants from all over Europe attended the workshop. The attendees were from industries (30 companies), universities and research institutes (20). In particular, all AEROCOINs partners as well as partners from the Nano-E2B Cluster attended the workshop. The attendees came from 16 different European countries (e.g. D, F, NL, DK, GR, N, E, B, SVN, FL,SE, CH) as well as Hong-Kong.
The workshop attracted a lot of interest in particular from industries and partners in Nano E2B projects. The vivid podium discussions at the end of each day as well as during coffee breaks and the dinner reflected the current importance of the workshop’s topics.
During the workshop the following key points for high performance thermal insulations (HPI) were addressed; hereby high performance insulation was defined by thermal conductivities < 0.02 W/(mK):
1) performance & handling
a) thermal conductivity
b) costs (added values, e.g. comfort for example with respect to moisture)
c) handling (easy to handle on construction site)
d) installation (time needed for installation, components required for installation that reduce the overall performance of the thermal insulation material, specific training of architects and craftsmen)
2) characterization of HPI components (homogeneity, on-site measurements)
3) building regulations, standards (extensions required?)
4) long term stability of thermal and mechanical properties of nanomaterials based HPI such as VIP cores, fumed or precipitated silica boards, aerogels (high surface energies, stability of hydrophobization)
5) recycling
6) health risks, public acceptance
In the current phase, costs and handling issues are key characteristics that represent thresholds that must be overcome to allow introduction of HPI into the market. In the second phase, installation related topics, standards and long term stability as well as public acceptance have to be addressed.
iii) The Final Conference was held in the frame of the VII International Congress on Architectural Envelopes organized by TECNALIA on the 27-29th May 2015 (www. http://icae.hei-tecnalia.com). The conference was organized together with AMANAC Cluster (www.amanac.eu) in which AEROCOINs is taking part very actively.
On the 27th an AMANAC entitled session was organized in which AEROCOINs project presented some of its developments. On the 28th a Fire Workshop took place. The full agenda for the conference can be found on the following webpage: http://www.icae2015.com.
The main objective of AMANAC session was to disseminate, promote, raise awareness on the latest results and the technologies developed within the cluster projects with the main focus put on the envelope application. Several participant projects gave talks around the following topics:
• High performance insulation systems based on aerogel-based materials.
• Nano-based HVAC systems
• Buildings with low embodied energy materials
• Lightweight materials and components for construction
• New materials/composites/paints for a Healthier indoor environment
• New materials for Smart windows
AEROCOINs project presented the next three presentations:
Mechanically robust pectin-silica nanocomposite aerogels: potential materials for thermal superinsulation
S.Zhao1 A. Demilecamps2, A.Rigacci3 L.Huber1 T. Budtova2,*, M.M. Koebel1,*
1Lab. for Building Energy Materials and Components, EMPA, CH; 2MINES ParisTech, Centre de Mise en Forme des Matériaux, France 3MINES ParisTech, Centre procédés, energies renouvelables et systems énergétiques, France
Full scale performance evaluation of Aerogel products and systems for building insulation
Ignacio del Val1 Roberto Garay2, Ewa A. Zukowska1 , Eunate Goiti2
1 Acciona Infraestructuras, Spain. 2 Tecnalia Research & Innnovation, Spain
Bio-aerogels: new promising materials for thermal superinsulation
Cyrielle Rudaz1, Arnaud Demilecamps1, Georg Pour1, Margot Alves1, Arnaud Rigacci2, Christian Beauger2, Claudia Hildenbrand2, Gudrun Reichenauer3, Tatiana Budtova1
1 Centre for Materials Forming (CEMEF), MINES ParisTech, France; 2Centre procédés, énergies renouvelables et systèmes énergétiques (PERSEE), MINES ParisTech, France; Bavarian Center for Applied Energy Research, Germany
The main objective of Fire Workshop was to make an overview on the fire aspects related to the buildings components and systems, and for doing so, the following topics were addressed:
• New trends in fire-retardant materials
• Reaction to Fire and Resistance to Fire Testing and related European Regulations: Challenges for advanced Materials
• Façade and Structural fire Testing: State of the Art and future needs
• Computational tools for Fire Research: Potentials and link to Performance based Codes.
The vivid podium discussions at the end of each day as well as during coffee breaks reflected the current importance of the conference topics.
This type of events represents a good opportunity to disseminate and also increase the impact of the projects such as AEROCOINs as the promising applications, uses and advantages of materials such as aerogels in the building envelope were presented in front of a wide audience composed of companies related to architectural envelopes and their components; Architectural and Engineering studies; Facade manufacturers; Developers and builders.
Participation at conferences, seminars, workshops outside the project framework
AEROCOINs consortium members took part in up to 70 events organized in different part of Europe. List of these events are included in Table A2.
Peer-reviewed publications
Six scientific papers have been published so far in indexed journals. A seventh paper has been recently submitted and additional ones are expected to be submitted in the following months. The list of papers is presented in Table A1.
Awards
ARMINES received an award from ADEME (French Agency for Energy and Environment) in innovation for materials for energy for 2014, based on the work performed on BIOAEROGELS within AEROCOINs. (see http://www.pollutec.com/prix-techniques-innovantes.htm).
Within AEROCOINs project a number of EXPLOITABLE RESULTS have been identified:
ER1 Trityl cellulose aerogels and their silica-based composites
ER2 Pectin-silica one-pot
ER3 Hot-wire characterization method suitable for small samples
ER4 Profile-based facade insulation system for highly insulating materials
ER5 Method of identification of critical stress point in ambient pressure drying
ER6 Knowledge for analysis, simulation procedures and sheltering principles
- New reinforcement strategies for silica aerogels (ER1 and ER2)
AEROCOINs have developed new reinforcement strategies for the silica based aerogels. These approaches are aiming at improving the mechanical properties of silica aerogels to obtain aerogels via ambient drying process.
An innovative cellulosic route to elaborate some reinforced silica-based superinsulating materials at lab-scale has been developed by ARM. The processing is based on impregnation of nanostructured hydrophobic cellulose matrix with a silica sol and gelation in the porosity of the superinsulating silica gel. The corresponding product does not present yet the targeted thermal conductivity and is still dried in supercritical conditions but the achieved level of conductivity is really promising (20 mW/m.K) and the basic mechanical properties are significantly increased.
As alternative and innovative ‘one pot’ route of reinforcement, cross-linked silica network with pectin biopolymer has also been explored for the elaboration of strong super-insulating aerogel composite materials by ARM and EMPA. The main innovation is ‘one-pot’ synthesis route, based on inexpensive sodium silicate.
SEP and PCAS industrial partners could be interesting in exploiting these results, however, there is an issue of importance, that is a common baseline in the area of aerogels , the high cost of the precursors/starting materials. This aspect could retrieve/delay the exploitation of these two results mainly for the application of the resultant aerogels, at least in the building sector. Therefore it is an important aspect to consider in future developments.
- Hot-wire characterization method suitable for small samples
A modified hot-wire set-up was developed by ZAE that allows analysis of thermal conductivity for small samples down to about 3 cm in diameter at height of about 1 cm. The method was validated within the AEROCOINs project.
- Profile-based facade insulation system for highly insulating materials
State of the art dry internal insulation systems rely on metal or wooden profiles/studs to mechanically bear the system and render. These solutions tend to produce relevant thermal bridge effects (above 30% reduction of insulation capacity) when used in highly insulated façades, and traditional solutions are not applicable when highly insulating materials such as aerogels are used. The profile system employed by TEC is independent of the aerogel material developed in AEROCOINs. Its target technical niche covers the integration of any superinsulation material (AEROGEL/VIP), or insulation materials below a threshold of λ≤0.020W/m2K.
- Method of identification of critical stress point in ambient pressure drying
TUL has developed a method that identifies the critical stress point when wet gels crack during Ambient Pressure Drying (APD). The method is based on the experimental analysis performed in a tunnel that can measure drying kinetics of solvent saturated gels under variable conditions and measure internal pressure in gel as a representative of stress formation inside.
- Knowledge for analysis, simulation procedures and sheltering principles
New materials have properties that differ from traditional materials, therefore, the building physics behaviours are also different. Reliable and verified simulation is one result of this research work within AEROCOINs. This can be used in all new superinsulation material concepts and also in different applications with different superinsulation materials. So it is not dependent of the material development in the project. Major risk in this result is if the used parameters in simulation are not practical, but this could be dealt by doing sensitivity analysis.
List of Websites:
www.aerocoins.eu
1 FUNDACION TECNALIA RESEARCH & INNOVATION Spain
Dr. Eunate Goiti
eunate.goiti@tecnalia.com
2 ASSOCIATION POUR LA RECHERCHE ET LE DEVELOPPEMENT DES METHODES ET PROCESSUS INDUSTRIELS - ARMINES France
Dr. Arnaud Rigacci
arnaud.rigacci@mines-paristech.fr
3 EIDGENOESSISCHE MATERIALPRUEFUNGS- UND FORSCHUNGSANSTALT EMPA Switzerland
Dr. Matthias Koebel
matthias.koebel@empa.ch
4 TEKNOLOGIAN TUTKIMUSKESKUS VTT Finland
Dr. Markku Leivo
Markku.Leivo@vtt.fi
5 POLITECHNIKA LODZKA TUL Poland
Dr. Zdzisław Pakowski
zdzislaw.pakowski@p.lodz.pl
6 BAYERISCHES ZENTRUM FUR ANGEWANDTEENERGIEFORSCHUNG ZAE EV Germany
Dr. Gudrun Reichenauer
Gudrun.Reichenauer@zae-bayern.de
7 PRODUITS CHIMIQUES AUXILIAIRES ET DE SYNTHESE SA France
Dr. Pierre-Andre Marchal
pierre-andre.marchal@pcas.com
8 SEPAREX SA France
Dr. Eric Francais
efrancais@separex.fr
9 ACCIONA INFRAESTRUCTURAS S.A. Spain
Ms. Ewa Zukowska
ewaalicja.zukowska@acciona.com
In the context of global climate control policies, improving the energy efficiency of existing buildings represents a great challenge, worldwide as well as at the European level. Reducing the energy consumption of buildings is nowadays preferably achieved by increasing the thermal resistance of the insulation layer in the building envelope.
The AEROCOINs project, in order to contribute to the future reduction of energy consumption by decreasing heating and cooling demands of existing-buildings, has been working on the clever combination of sol-gel science and nanotechnology aiming to advance on the design and development of novel super-insulating aerogels.
The AEROCOINs project has developed new reinforcement strategies in order to produce mechanically strong super-insulating aerogel composite/hybrid materials. The main approaches developed are based on the employment of two polysaccharides materials: cellulose and pectin, respectively. These strategies open new possibilities for further development of superinsulating materials.
It was found in this project that the critical stress point when wet gels crack during Ambient Pressure Drying (APD) can be found by measuring the internal pressure evolution. This valuable information can be used to reduce the drying rate before the crack develops. In the current state-of-the art it is commonly assumed that this point roughly corresponds to transition from the constant to the falling rate period, which requires sample mass monitoring in situ.
For the thermal characterization of this type of highly insulating materials, an optimized hot-wire method has been developed within AEROCOINs, which permits the characterization of very small samples (down to diameters of about 27 mm). This method has been validated by comparing it to measurement with the same set-up on larger samples and comparing it to hot-plate results.
In addition, an efficient ambient pressure drying process and optimization on the supercritical drying process have allowed the up-scaling manufacture of aerogel boards. Designing and fabricating a novel building component prototype based on the developed aerogel-like material has yield a component compatible with conventional construction installations where the envelope is part of the buildings. This building component integrates low-conductive plastic-composite profiles and plasterboard renders within a multi-layer arrangement, and it has obtained the best fire classification for organic materials: B-s1,d0.
Demonstration of the structural, mechanical and thermal performance of the insulating component under real conditions have been performed in two demo buildings (in the DemoPark in Madrid and KUBIK in Bilbao) and compared with conventional insulating materials.
Project Context and Objectives:
World energy demand is expected to increase by up to 71% between 2003 and 2030. As it is defined by the International Energy Agency (IEA) the energy future demand has to be a balance between the “three Es”: Environmental protection, Energy security and Economic growth. Different researches have indeed concluded that the only way to avoid a drastic increase of energy consumption is to achieve an order-of-magnitude improvement in Energy-Efficiency (EE), defined as the ratio between energy services provided and energy consumed.
According to the Buildings Performance Institute Europe (BPIE) the residential stock in Europe is the biggest segment with a floor space of 75% of the building stock and accounts for the 68% of the total final energy use in buildings . Space heating is the most energy intensive end-use in homes accounting for 70% of the total final energy use. This is due to the fact that more than 40% of the European residential buildings were constructed before the 1960s, when energy building regulations were very limited, and have not undergone renovations to improve energy performance, meaning that, these have low insulation levels and their systems are old and inefficient. One approach to improve energy efficiency of buildings is to enhance the thermal resistance of the envelope.
The development of advanced insulation technologies for energy efficient buildings is a very promising field. Indeed, the emerging field of superinsulating materials for new and retrofitting buildings, thanks to nanotechnology, has great promise to contribute to this unique domain of sustainable development.
Based on the “global” assessment that silica is the ideal raw material for large-scale commercial insulation application for buildings, the present project restricts its research area on a well-defined selection of improvement strategies for the silica-based aerogel composite/hybrid systems. The central goal is to capitalize on partners’ expertise and their deep knowledge of the state-of-the-art described in the literature by finding new and/or complimentary ways to manufacture superinsulating and strong very efficient aerogel-like materials.
The main goal of the AEROCOINs project was to develop a new composite/hybrid aerogel material to improve the insulating performance of existing buildings aiming at reducing their energy demands. Hence, the main objectives were:
OG1.- to synthesize and elaborate novel, mechanically strong and superinsulating aerogel-based materials via a subcritical ambient drying process.
OG2.- to design and fabricate a highly efficient and robust building component (based on the developed aerogel composite and/or hybrid material) for its implementation in the external part of the envelope of existing buildings.
OG3.- to demonstrate the significant cost reduction of the commercial production of superinsulating aerogel-like materials and hence also of the component.
These general objectives were expected to be achieved through the development and completion of complementary work packages. These, were based on the following specific scientific and technical objectives:
S&T O - Related to the elaboration and development of a composite/hybrid aerogel material.
1. To obtain a reinforced aerogel-based superinsulator material: improvement of mechanical properties (an improvement of up to 100 times versus plain silica aerogel) while maintaining thermal conductivity at a very low level (λ< 0.018Wm-1K-1) by cross-linking and/or nanodispersion concepts.
2. To promote multifunctionality of the so-obtained superinsulating materials: for example, enhancement of flame retardancy with mineral nanodispersion in the sol.
3. To develop a subcritical ambient drying process: minimize evaporation-induced shrinkage thanks to an optimized fine-coupling between sylilation chemistry of the silica network and strengthening techniques (cross-linking and nanodispersion).
S&T O – Related to the design and development of the insulation façade construction component.
4. To transfer the chemical process technology of best candidate lab-scale materials to the pilot scale (including both, the synthesis and ambient pressure drying processes for the elaboration of large monolithic superinsulating boards of 50 x 50 x 1 cm3 dimensions.
5. To design and fabricate a brand-new building component prototype based on the developed aerogel-like material, which will need to be compatible with conventional construction installations for implementation into the envelope part of buildings.
6. To design a cost-effective continuous industrial-level process for the production of the aerogel-like material board.
S&T O – Related to the validation of the efficiency of the insulation façade component and building integration.
7. To demonstrate the thermal performance of the highly insulating component under real conditions.
8. To demonstrate the structural and mechanical performance of the insulating component under real conditions.
To accomplish its objectives, the AEROCOINs project was structured into seven workpackages (WP), five of which address specific technical objectives (WP1-WP5), one of them is devoted to dissemination and exploitation issues (WP6) and the last one to management activities (WP7).
The seven WPs were the following:
The WP1- Synthesis of reinforced superinsulating aerogels was focused on the design and synthesis of brand new superinsulating silica-based aerogels. The main technical and scientific objective of WP1 has been to optimize the soft-chemistry processes for the preparation of such superinsulating silica-based aerogel-like materials i) to promote their mechanical reinforcement and ii) their multifunctionality, without degrading their very low thermal conductivity.
The WP2 - Drying and thermal conductivity optimization dealt with the development and optimization of a robust and efficient drying process to be transferred at pilot scale (in WP3) for elaboration of strong superinsulating aerogel-like boards. The main technical objective of WP2 was to develop an effective lab-scale subcritical ambient pressure drying (SAPD) process i) able to minimize shrinkage and cracking during evaporation, ii) permitting to obtain 10cm×10cm×1cm monolithic aerogel plates and iii) well-suited for further transfer to pilot scale. WP2 also aimed at adapting standard supercritical drying (SCD) process to the specificities of the brand new organic/inorganic gels synthesized within WP1. Because of its higher degree of maturity, the SCD route would provide the so-called “plates of reference”.
The WP3- Pilot scale material fabrication focused on the design and fabrication of new superinsulating aerogel board (of 50cm×50cm×1cm dimensions). The 3 main technical objectives of WP3 were i) up-scaling of optimized materials (at least one solution chosen from WP1-WP2), ii) to produce sufficient amounts of the selected best-case aerogel boards for the component manufacture in WP4 and iii) to perform an analysis of the potential for up-scaling and large-scale industrial fabrication of the aerogel boards. This included the design of a continuous fabrication scheme and a complete volume and parameter dependent cost estimation.
The WP4- Aerogel-based component manufacturing dealt with the design and fabrication of new superinsulating building components for retrofitting installations. The main technical objective of WP4 has been the customization of individual aerogel boards to yield a component which is compliant with current insulating systems and solutions and can be used directly in construction.
The WP5- Building integration and validation dealt with energy efficiency demonstration activities and its main objective was the integration of the component (obtained in WP4) in a demonstrator building to validate its thermal, mechanical and structural performance under real conditions.
The WP6-Dissemination and exploitation aimed at finely studying the global impact of the developed superinsulating silica-based aerogel-like materials for improving energy efficiency in buildings and to set up the academic/industrial dissemination and exploitation strategies of the outputs of the project.
Finally, the WP7-Project Management had as a main objective to ensure a sound coordination and management of the project covering administrative, legal and financial issues, and the relation with the EC.
Project Results:
The main scientific and technical results of AEROCOINs project are described in this section. They can be divided in the following categories:
1. Developments on the sol-gel chemistry in order to prepare reinforced silica-based aerogel materials.
2. Characterization of Aerogel materials.
3. Development of the up-scaling process for the fabrication of aerogel material.
4. Life cycle analysis of aerogel materials.
5. Aerogel-based building component design and evaluation.
1. DEVELOPMENTS ON THE SOL-GEL CHEMISTRY IN ORDER TO PREPARE REINFORCED SILICA-BASED AEROGEL MATERIALS
Different chemical strategies have been pursued for the reinforcement of silica aerogels, based on crosslinking and nanodispersion approaches. Herein, the main achievements are described.
New strong polysaccharide and polysaccharide-silica aerogels have been developed within AEROCOINs. Two polysaccharides were used for this purpose: cellulose and pectin. Silica sol was polyethoxydisiloxane (PEDS), a product from PCAS.
Cellulose-based aerogels
a) New experimental set-up for accelerating the impregnation of silica sol into cellulose matrix, and strong cellulose-silica aerogels have been developed by ARMINES
Strong, light (bulk density around 0.2 g/cm3) and monolithic crack-free cellulose-silica composite aerogels have been prepared by impregnation of wet coagulated cellulose with PEDS-based solution. The impregnation was performed either by molecular diffusion or by a forced flow process (due to a pressure gradient). The latter allowed an enormous decrease in the impregnation times, by almost three orders of magnitude. In both cases, nanostructured silica gel was in situ formed inside cellulose matrix porosity.
Nitrogen (N2) adsorption analysis revealed an almost threefold increase in specific surface area, from cellulose aerogel alone to their organic-inorganic composite counterparts. Thermal conductivity of composite aerogels was lower than that of cellulose aerogel due to the formation of mesoporous silica inside cellulose pores. Composite aerogels were strongly reinforced as compared with the reference aerogels still keeping high ductility characteristic of Aerocellulose (i.e. pure cellulose aerogels): Young modulus increased by 3-4 times and fracture strain remained very high, about 60%.
b) Thermal super-insulating hydrophobic and monolithic cellulose-silica aerogels
Hydrophobic cellulose-based aerogels and their organic-inorganic counterparts were synthesized and characterized by ARMINES. Cellulose was chemically modified with triphenylmethyl chloride in homogeneous conditions; composite aerogels were prepared by impregnation of coagulated tritylcellulose by PEDS which was then in situ gelled in the porous cellulosic matrix (Figure 1). Silica phase was subsequently hydrophobised with HMDZ (hexamethydisilazane) and composite samples were dried with supercritical CO2.
The impregnation approach and hydrophobization of both phases resulted in new organic-inorganic monolithic thermal super-insulating aerogels with the thermal conductivity significantly below that of air at ambient conditions, 0.021-0.022 Wm-1K-1, and good resistance (in weight and volume) towards humidity in the conditions studied (at 30°C and 80%RH for 24 hours). The obtained organic-inorganic aerogels are finely nanostructured, with very high specific surface area (between 600 and 800 m2/g depending on synthesis parameters), and highly hydrophobic, with water contact angles 133-135°. Tritylcellulose aerogels are highly compressible, with zero Poisson’s ratio. The mechanical properties of composite organic-inorganic aerogels are strongly improved as compared with pure silica aerogels.
c) Nanofibrillated cellulose dispersion route
Compounding of PEDS gels with unmodified, maleic anhydride esterified and TEMPO oxidized NFC works in principle, yielding monoliths via supercritical drying; mechanical reinforcement in compression is nonexistent but in tension there is a 50% improvement.
Figure 2. .Cellulose-silica aerogels prepared from nanofibrillated cellulose (EMPA)
d) Cellulose foams route
Since a poor dispersion of the cellulosic fibers in silica sol was observed, an alternative route was developed by EMPA for compounding of PEDS gels with unmodified and silylated modified NFC foams. The approach uses freeze drying of nanofibrillated cellulose in presence of MTMS. The E-modulus of the composites increased, but fracture toughness remained the same or was slightly lowered. Thermal conductivity values were around 0.016 W/(m K) at room condition for the composites reinforced with the MTMS modified foams, while values significantly higher (0.018-0.020 W/(m K)) were obtained for silica reinforced with the unmodified foams.
Figure 3. Cellulose-silica aerogels reinforced with silylated NFC foams (EMPA)
Pectin-based aerogels
Pectin based aerogels can be obtained applying crosslinking and nanodispersion approaches:
e-1) 100% pectin strong and monolithic thermal super-insulating aerogels via cross-linking
Pectin-based aerogels were synthesised via cross-linking of pectin with Ca2+ by ARMINES. Finely nanostructured Aeropectins with extremely low densities (0.02 – 0.06 g/cm3) were thus obtained, showing high specific surface areas (200-300 m2.g-1). Such Aeropectins are able to sustain up to 80-90% strain without breaking. The associated thermal conductivity is remarkably low, 0.015-0.023 W/(m.K) at room conditions (Figure 2). This fully biobased aerogel is thus completely falling in the range of true thermal super-insulating materials.
e-2) Pectin route via nanodispersion
In the nanodispersion approach pectin biopolymer has also been employed. Using one-pot mixing of dissolved pectin with sodium silicate, monolithic pectin-silica aerogels with super-insulating properties could be obtained via SCD; the thermal conductivity values of the resulting composites range from 0.016-0.022 W/(m K).
Figure 5. ‘One-pot’ pectin-silica aerogels designed by EMPA &ARMINES
f) Super-insulating pectin-silica aerogels.
Pectin-silica composite aerogels were prepared via impregnation of pectin matrix, using the same approach as developed for cellulose-silica composite aerogels. Hereby the silica phase was hydrophobized. Higher density as compared to the neat Aeropectin (0.10 – 0.15 g/cm3), and huge specific surface area (800-850 m2.g-1) were obtained. Pectin-silica aerogels were also super-insulating with the conductivity 0.015-0.023 W/(m.K) (Figure 5). The contact angle with water was around 135° and humidity uptake was strongly decreased as compared to neat Aeropectin at the same conditions.
2. CHARACTERIZATION of AEROGEL MATERIALS
Several characterization tools have been employed for the characterization of the developed aerogel materials and also for optimizing the synthesis strategies in reducing the thermal conductivity of silica aerogel based composites on one hand and improving their mechanical properties for handling and application on the other hand.
For the thermal characterization of this type of highly insulating materials, an optimized hot-wire method has been developed by ZAE within AEROCOINs, which permits the characterization of very small samples (down to diameters of about 27 mm). This method has been validated by comparing it to results derived with the same set-up on larger samples and comparing it to hot-plate results.
Structural and mechanical characterization was performed to provide first trends in terms of the two contributions, solid and gas phase thermal transport to the overall thermal conductivity (see Figure 6). After a cross validation of the methods with lab scale samples provided by the AEROCOINs partners, aerogel samples were analyzed with respect to their thermal properties at ambient conditions as well to their Young’s moduli.
Figure 6: The measurement of the Young’s modulus and the specific BET-surface area (pore size) provide quantities that allow for an identification of trends in terms of contributions to the total thermal conductivity to be expected. The later can also be measured at ambient conditions representing a superposition of the solid phase and the gas phase contribution. The two effects can be separated by measuring the gas pressure dependence of the thermal conductivity (p), with (p0)= solid.
The evaluation of the thermal conductivity of some aerogels reinforced with vinyl polymers (prepared by TEC) reveals that the thermal conductivities as determined at ambient conditions decrease with density down to about a density of about 150 kg/m3 and then saturate at 0.013 to 0.014 W/m K. In other cases, i.e. some aerocellulose-based aerogels, high thermal conductivities are obtained due to a combination of a high heat transport along the solid phase and a large fraction of macropores also present in the composites.
In general, for the nanofibrillated cellulose based aerogels the incorporation of individual NFC fibres into the aerogels yielded materials with poorer or equivalent mechanical properties; the elastic modulus was observed to decrease slightly, while no change was observed in the compressive strengths. However, the tensile properties were observed to increase by about 50 % with the addition of lower concentrations of NFC. The presence of the fibres does not affect the thermal conductivities of the aerogels or increased them slightly.
In the case of Cellulose foams route combined with supercritical drying, the presence of unmodified NFC foams within the silica aerogel caused a deterioration of the mechanical properties, as exemplified by the gradual decrease in elastic modulus (E), compressive strength and fracture strain with increasing NFC mass fraction. A significant improvement of mechanical properties is observed when the silica is interpenetrated with silylated NFC foams. In comparison with the reference silica aerogel, these composites display a maximum increase in E of 55 %. All composites displayed thermal conductivities of 0,020 W/m·K or less which makes them superinsulating materials.
For the supercritical dried pectin based aerogels, in general, the elastic modulus (E), compressive strength and fracture strain strongly depend on pectin loading and pH fabrication value. The most significant improvement of the optimized composite displayed an increase in E, final compressive strength and fracture strain of 9.4 MPa/ 27.5 MPa/ >80%. All composites displayed thermal conductivity values below 0.017Wm-1K-1 which shows that they are true superinsulating materials.
Figure 7. (a) Strain-stress curve (b) Thermal conductivity (c) Compressive strength and (d) E modulus of the supercritical dried NFC foam reinforced PEDS-P750E20 aerogels synthesized at different pH values.
3. DEVELOPMENT OF THE UP-SCALING PROCESS FOR THE FABRICATION OF AEROGEL MATERIAL
An ambient pressure drying process (EMPA) has been developed and applied in the manufacturing of aerogel boards in AEROCOINs. The reactors were constructed from corrosion resistant (HCl) grade stainless steel and are designed for 22 samples of 50×50×2 cm³ per batch. The main steps for the fabrication of the boards are as follows:
Stage 1: Sol-gel process: In a first step, lab-scale recipes were adjusted to the large scale reactors and the gelation and aging processes optimized. In a typical batch, 190 liters of the sol with 30% of the PEDS-P75E20 precursor content (55.1L) was stirred with ammonia and then transferred into the gelation reactor.
Stage 2: Gelation and aging process of the aerogel composites: After keeping sols at 55oC for 2 hours, the gelation and aging proceeded simultaneously and the hydrogel blocks were lifted for checking the strength and removing the extra gels between plates.
Stage 3: Hydrophobization process of the aerogel composites. After aging, the hydrophobization of the gels is initiated by using HMDSO (the HMDSO can be recycled for next batches use) with catalytic amount HCl/Ethanol solution for 15 hours.
Stage 4: Ambient drying of the aerogel composites: After hydrophobizaton, the gels are dried employing the drying profile: 3 hours at 150°C.
Figure 8. Fabrication of ambient pressure drying of the prototype board of aerogel: (A) the hydrogels moved out of the aging container (B) wet gels moved to modification reactor (C) silylated gels take out from modification (D) aerogels after drying.
4. LIFE CYCLE ANALYSIS (LCA) OF AEROGEL MATERIALS
An LCA assessment for the production of silica aerogel insulation has been developed and compared with conventional insulation materials made from oil or mineral bases.
Life cycle analysis has been performed for two silica aerogel production routes: for ambient drying and for supercritical drying processes, respectively. (Even if the scope of AEROCOINs was the development of ambient drying process, supercritical drying has also been employed).
The LCA assessment is made according to the basic principles of LCA methodology (ISO 14040/14044). The main goal was to use the data from European Life Cycle database (ELCD) but due to the limitation of this database, the LCA has taken also existing literature data.
The assessment covers also some variation in raw-material routes and electricity production method. Normally the life cycle of a product assessment covers all the phases of the product life but as this is a novel product and thus its environmental impact size is not known, only production phase (A1 – A3) and global warming potential (GWP) is taken into consideration. Thus the assessment covers life cycle stages from “cradle to factory gate” including information from raw material supply, transportations, manufacturing of products and all upstream processes.
Total GWP for aerogel life cycle stages A1 - A3: GWP impacts for the aerogel life cycle stages A1 – A3 (raw material acquisition, transportation and production) calculated per 0.11 m3 aerogel board for ambient drying- and 0.06 m3 for the supercritical product. The result is shown in Table 1,
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Table 1. GWP results for the aerogel production (0.11 m3). Electricity, which used in production process, has low GWP (140 g/kWh). Production life cycles are: raw-materials (A1), raw material transportation (A2) and aerogel production (A3). A1 considers that virgin HDMSO is used by 7 % and virgin ethanol is used by 2%.
A1
kg CO2e A2
kg CO2e A3, low
kg CO2e Total,
A1-A3, low
kg CO2e Relative impact, %
Sol gel preparation 50 9.5 0.74 60 52 %
Gelation and aging 5 0.0063 0.71 5.2 5 %
Hydrophobization 33 0.33 2.0 35 31 %
Ambient drying 13 13 12 %
Total, kg/0.11 m3 aerogel 88 9.9 17 114 100 %
Total, kg/kg aerogel 7.3 0.82 1.4 9.5 100 %
Table 2. GWP results for the supercritical aerogel production (batch size 0.06 m3). Electricity, which used in production process, has low GWP (140 g/kWh). Life cycles are: raw-materials (A1), raw material transportation (A2) and aerogel production (A3). A1 considers that ethanol and isopropanol is recycled and only 1% of virgin substance is used.
A1
kg CO2e A2
kg CO2e A3, low
kg CO2e Total,
A1-A3, low
kg CO2e Relative impact, %
Sol gel preparation 22 4.2 26.2 31%
Gelation and aging 3.1 0.93 3.2 5%
Hydrophobization 2.8 0.0018 2.8 3%
Total for production 50.6 50.6 61%
Total, kg/0.06 m3 supercritical aerogel 28 5.1 51 83.3 100%
Total, kg/kg supercritical aerogel 4.2 0.78 7.7 12.6 100%
Figure 9. GWP share for Aerogel life cycle A1-A3.respectively for ambient drying and supercrithical drying product. Electricity used in production produced with low GWP.
The assessment is also made for the aerogel use. The GWP result is compared on the level of building components with alternative insulation solutions (building components with traditional insulation materials with the same performance and for the case of renovation with 100 mm additional aerogel in Northern or Southern Europe use). Figure 8 shows the example of energy saving, which is presented for one analysed case.
Figure 10. Annual heat losses and savings compared to the 100 mm mineral wool insulation, cases Finland and Spain.
5. AEROGEL BASED BUILDING COMPONENT DESIGN AND EVALUATION
A building integration framework has been generated, as it is directly linked with the format in which the material/building component is available. The defined integration framework targeted at internal insulation systems for building retrofitting, as this application provided the most suitable environment for the competitive advantage of superinsulation: reduced use of space in locations with space constraints.
Several alternatives were discussed, and integration of laminated aerogel boards in plasterboard based solutions was approached. However, when manufacture tests were conducted with up-scaled aerogel processes, this solution was evaluated inadequate for full-scale deployment, and an alternative building component was proposed. This finally developed building component integrates all the elements needed for the building integration of aerogel boards, as it incorporates all the elements previously defined as part of the construction system for building integration. The final version of the prototype consists of: 2 aerogel boards closed between two polymeric profiles and covered on one side by the reflexive cover and on the other side by the plaster board (Figure 11).
Figure 11. Prototype selected for the further studies
In AEROCOINS, a novel approach has been provided to the use of structural reinforcement profiles for internal insulation systems. State of the art dry internal insulation systems rely on metal or wooden profiles/studs to mechanically bear the system and render. Along the project, it was realized that these solutions tend to produce relevant thermal bridge effects (above 30% reduction of insulation capacity) when used in highly insulated façades, and traditional solutions are not applicable when highly insulating materials such as aerogels are used. Therefore, TEC has applied plastic composite based solutions which provide a high performing solution to this problem.
The moisture performance was also evaluated as relevant. This issue was approached through the evaluation under typical construction environments by VTT, where assessments in typical building applications under cold and warm climate conditions were performed. The moisture performance principles, required protection means against moisture loads and the moisture risks in the aerogel applications were studied. Only the performance of AEROCOINs aerogel materials were studied, other materials were assumed to have safe moisture performance in the presented assembly.
Example of simulation performance is presented in Figure 12. In this simulation performance in Malaga (south Spain) was examined in undamaged composite. Also effects of different structure and small damages were investigated both in Finland and Spanish climatic conditions.
Figure 12. Simulation of relative humidity values for the exterior (ext) and interior (int) surfaces of aerogel thermal insulation under Malaga climate (south Spain).
To verify used parameters in simulations also experimental investigation was performed. In these test the aerogel component was subjected to different moisture loadings and moisture behaviour was followed. Example of these tests is presented in Figure 13. In the test, component is subjected to 95%RH moisture. In the test, a moisture barrier prevents moisture accumulation. Even small nail or drill hole did not cause dramatic weakening in moisture behaviour.
Figure 13. Panel interior humidity when subjected to high relative humidity in moisture barrier side.
According to simulations and measurements the moisture damage risks were higher in cold northern climate than in warm climate conditions. This is due to the higher temperature and partial vapour pressure gradients in structures and the also the lower drying capacity of the structures under cold conditions. These differences set also different requirements for the protection of aerogel insulation layer under different climate loads, something to be considered for further designs of aerogel-based materials.
On the other hand, concerning the fire retardant properties of this type of materials, indicative Single Burning Item (SBI) test and inflammability test were performed by TEC. Organic modified silica-based aerogels developed in AEROCOINs ignited very quickly as soon as the burner was on. Hence, the peak of the heat release was very high. Once the organic part burns, the inorganic part starts to fall down. This phenomenon should be considered the final of the test (according to EN13823 standard and an E classification would be declared). The sample did not ignite neither propagate after the application of the flame. However, the building component based on the aerogel materials has obtained the best fire classification for organic materials: B-s1,d0.
AEROCOINs has evaluated the performance of aerogel materials in two demo buildings, KUBIK in Bilbao by TEC and DemoPark in Madrid by ACC, respectively. Test set-ups were constructed and monitorization campaigns performed over roughly 6 months where the overall thermal and mechanical performance of building components was evaluated. Results from demonstration reached the performance obtained at laboratory scale, and that in all cases superinsulated assemblies were obtained.
Figure 14. Left: External view of the test set-up for Aerocoins at the Kubik test facility in Bilbao (Spain). Right: DemoPark in Madrid, Spain.
Potential Impact:
The DISSEMINATION EFFORTS undertaken within the AEROCOINs project were aimed at communicating and disseminating the relevance and importance of super-insulating materials aerogels, mainly for the building application. Over last years, the European Commission has boosted innovative measures to improve Europe´s energy efficiency and to contribute to the objectives 40-27-27 by 2030 . Specific Directives , energy labels and standards for products save money which can partially result in new job creation. Under this context, AEROCOINs has aimed at communicating the developments of high insulation performance aerogel based materials developed within the project.
Dissemination activities were deployed at two levels: consortium/project level as well as by individual project partners using their own dissemination channels and networking relationships. Below the main dissemination channels and respective activities developed within AEROCOINs are presented.
Project website and mailings:
AEROCOINs project web site (www.aerocoins.eu) was created as a primary source of information about the project activities and its key outputs. Some visual materials that have been presented there include public deliverables, information on relevant events, list of dissemination activities, and list of publications.
Mailings as a dissemination channel were also used. Since the creation of AEROCOINs website it has received a total of 8.023 visitors, with a 72.2% of new visitors and a 27.8% of returning visitors.
Restricted access zone of the web site
To ensure proper dissemination of project outcomes amongst project partners, a restricted access zone was created within AEROCOINs web site. All key documents, restricted deliverables, working presentations, minutes of the meetings have been uploaded for internal consortium use.
Workshops and Conferences:
Two AEROCOINs workshops and a final conference have been organized.
i) 1st AEROCOINS workshop “Superinsulation Aerogel Materials for Energy Efficiency” was organized by ARMINES and TECNALIA on the 19th of June 2012 in Sophia Antipolis (France).
The goal of the workshop was to engage external academic and industrial experts together with Aerocoins partners in scientific and technical discussions and exchanges concerning the opportunities arising from the current demand in Europe for Energy Efficient Materials particularly focused on superinsulating aerogel materials for strategic sectors (building, space, …).
More than 30 persons from Finland, France, Germany, Poland, Portugal, Spain and Switzerland participated to the work-shop. There were about 10 representatives from companies, and also from agencies related to building industry. About 20 participants were from public research laboratories and universities.
The work-shop showed a lot of interest from all players, both at industry and academy levels, involved in the development of efficient insulation materials for building envelopes applications. The presentations were followed by questions and discussions; the exchanges on hot topics continued during lunch and poster presentations.
ii) 2nd AEROCOINs Workshop “High Performance Thermal Insulation (HPI) 2013 - Towards Near Zero Energy Buildings” organized by ZAE and TECNALIA at the Energy Efficiency Center (EEC), ZAE Bayern (Würzburg, Germany) on the 27/28th of November 2013.
The focus of the workshop was specifically more on competitive insulation systems and integration rather than materials synthesis.
In particular, the workshop aimed at bringing together the people in the field of thermal insulation, building physics and architecture to:
• Present recent developments in terms of insulation materials and components suited for building applications;
• Address problems to be solved upon integration and combination of new components towards zero energy buildings;
• Give an overview over current demo-activities;
• Discuss degradation and recycling issues related to next generation buildings.
90 participants from all over Europe attended the workshop. The attendees were from industries (30 companies), universities and research institutes (20). In particular, all AEROCOINs partners as well as partners from the Nano-E2B Cluster attended the workshop. The attendees came from 16 different European countries (e.g. D, F, NL, DK, GR, N, E, B, SVN, FL,SE, CH) as well as Hong-Kong.
The workshop attracted a lot of interest in particular from industries and partners in Nano E2B projects. The vivid podium discussions at the end of each day as well as during coffee breaks and the dinner reflected the current importance of the workshop’s topics.
During the workshop the following key points for high performance thermal insulations (HPI) were addressed; hereby high performance insulation was defined by thermal conductivities < 0.02 W/(mK):
1) performance & handling
a) thermal conductivity
b) costs (added values, e.g. comfort for example with respect to moisture)
c) handling (easy to handle on construction site)
d) installation (time needed for installation, components required for installation that reduce the overall performance of the thermal insulation material, specific training of architects and craftsmen)
2) characterization of HPI components (homogeneity, on-site measurements)
3) building regulations, standards (extensions required?)
4) long term stability of thermal and mechanical properties of nanomaterials based HPI such as VIP cores, fumed or precipitated silica boards, aerogels (high surface energies, stability of hydrophobization)
5) recycling
6) health risks, public acceptance
In the current phase, costs and handling issues are key characteristics that represent thresholds that must be overcome to allow introduction of HPI into the market. In the second phase, installation related topics, standards and long term stability as well as public acceptance have to be addressed.
iii) The Final Conference was held in the frame of the VII International Congress on Architectural Envelopes organized by TECNALIA on the 27-29th May 2015 (www. http://icae.hei-tecnalia.com). The conference was organized together with AMANAC Cluster (www.amanac.eu) in which AEROCOINs is taking part very actively.
On the 27th an AMANAC entitled session was organized in which AEROCOINs project presented some of its developments. On the 28th a Fire Workshop took place. The full agenda for the conference can be found on the following webpage: http://www.icae2015.com.
The main objective of AMANAC session was to disseminate, promote, raise awareness on the latest results and the technologies developed within the cluster projects with the main focus put on the envelope application. Several participant projects gave talks around the following topics:
• High performance insulation systems based on aerogel-based materials.
• Nano-based HVAC systems
• Buildings with low embodied energy materials
• Lightweight materials and components for construction
• New materials/composites/paints for a Healthier indoor environment
• New materials for Smart windows
AEROCOINs project presented the next three presentations:
Mechanically robust pectin-silica nanocomposite aerogels: potential materials for thermal superinsulation
S.Zhao1 A. Demilecamps2, A.Rigacci3 L.Huber1 T. Budtova2,*, M.M. Koebel1,*
1Lab. for Building Energy Materials and Components, EMPA, CH; 2MINES ParisTech, Centre de Mise en Forme des Matériaux, France 3MINES ParisTech, Centre procédés, energies renouvelables et systems énergétiques, France
Full scale performance evaluation of Aerogel products and systems for building insulation
Ignacio del Val1 Roberto Garay2, Ewa A. Zukowska1 , Eunate Goiti2
1 Acciona Infraestructuras, Spain. 2 Tecnalia Research & Innnovation, Spain
Bio-aerogels: new promising materials for thermal superinsulation
Cyrielle Rudaz1, Arnaud Demilecamps1, Georg Pour1, Margot Alves1, Arnaud Rigacci2, Christian Beauger2, Claudia Hildenbrand2, Gudrun Reichenauer3, Tatiana Budtova1
1 Centre for Materials Forming (CEMEF), MINES ParisTech, France; 2Centre procédés, énergies renouvelables et systèmes énergétiques (PERSEE), MINES ParisTech, France; Bavarian Center for Applied Energy Research, Germany
The main objective of Fire Workshop was to make an overview on the fire aspects related to the buildings components and systems, and for doing so, the following topics were addressed:
• New trends in fire-retardant materials
• Reaction to Fire and Resistance to Fire Testing and related European Regulations: Challenges for advanced Materials
• Façade and Structural fire Testing: State of the Art and future needs
• Computational tools for Fire Research: Potentials and link to Performance based Codes.
The vivid podium discussions at the end of each day as well as during coffee breaks reflected the current importance of the conference topics.
This type of events represents a good opportunity to disseminate and also increase the impact of the projects such as AEROCOINs as the promising applications, uses and advantages of materials such as aerogels in the building envelope were presented in front of a wide audience composed of companies related to architectural envelopes and their components; Architectural and Engineering studies; Facade manufacturers; Developers and builders.
Participation at conferences, seminars, workshops outside the project framework
AEROCOINs consortium members took part in up to 70 events organized in different part of Europe. List of these events are included in Table A2.
Peer-reviewed publications
Six scientific papers have been published so far in indexed journals. A seventh paper has been recently submitted and additional ones are expected to be submitted in the following months. The list of papers is presented in Table A1.
Awards
ARMINES received an award from ADEME (French Agency for Energy and Environment) in innovation for materials for energy for 2014, based on the work performed on BIOAEROGELS within AEROCOINs. (see http://www.pollutec.com/prix-techniques-innovantes.htm).
Within AEROCOINs project a number of EXPLOITABLE RESULTS have been identified:
ER1 Trityl cellulose aerogels and their silica-based composites
ER2 Pectin-silica one-pot
ER3 Hot-wire characterization method suitable for small samples
ER4 Profile-based facade insulation system for highly insulating materials
ER5 Method of identification of critical stress point in ambient pressure drying
ER6 Knowledge for analysis, simulation procedures and sheltering principles
- New reinforcement strategies for silica aerogels (ER1 and ER2)
AEROCOINs have developed new reinforcement strategies for the silica based aerogels. These approaches are aiming at improving the mechanical properties of silica aerogels to obtain aerogels via ambient drying process.
An innovative cellulosic route to elaborate some reinforced silica-based superinsulating materials at lab-scale has been developed by ARM. The processing is based on impregnation of nanostructured hydrophobic cellulose matrix with a silica sol and gelation in the porosity of the superinsulating silica gel. The corresponding product does not present yet the targeted thermal conductivity and is still dried in supercritical conditions but the achieved level of conductivity is really promising (20 mW/m.K) and the basic mechanical properties are significantly increased.
As alternative and innovative ‘one pot’ route of reinforcement, cross-linked silica network with pectin biopolymer has also been explored for the elaboration of strong super-insulating aerogel composite materials by ARM and EMPA. The main innovation is ‘one-pot’ synthesis route, based on inexpensive sodium silicate.
SEP and PCAS industrial partners could be interesting in exploiting these results, however, there is an issue of importance, that is a common baseline in the area of aerogels , the high cost of the precursors/starting materials. This aspect could retrieve/delay the exploitation of these two results mainly for the application of the resultant aerogels, at least in the building sector. Therefore it is an important aspect to consider in future developments.
- Hot-wire characterization method suitable for small samples
A modified hot-wire set-up was developed by ZAE that allows analysis of thermal conductivity for small samples down to about 3 cm in diameter at height of about 1 cm. The method was validated within the AEROCOINs project.
- Profile-based facade insulation system for highly insulating materials
State of the art dry internal insulation systems rely on metal or wooden profiles/studs to mechanically bear the system and render. These solutions tend to produce relevant thermal bridge effects (above 30% reduction of insulation capacity) when used in highly insulated façades, and traditional solutions are not applicable when highly insulating materials such as aerogels are used. The profile system employed by TEC is independent of the aerogel material developed in AEROCOINs. Its target technical niche covers the integration of any superinsulation material (AEROGEL/VIP), or insulation materials below a threshold of λ≤0.020W/m2K.
- Method of identification of critical stress point in ambient pressure drying
TUL has developed a method that identifies the critical stress point when wet gels crack during Ambient Pressure Drying (APD). The method is based on the experimental analysis performed in a tunnel that can measure drying kinetics of solvent saturated gels under variable conditions and measure internal pressure in gel as a representative of stress formation inside.
- Knowledge for analysis, simulation procedures and sheltering principles
New materials have properties that differ from traditional materials, therefore, the building physics behaviours are also different. Reliable and verified simulation is one result of this research work within AEROCOINs. This can be used in all new superinsulation material concepts and also in different applications with different superinsulation materials. So it is not dependent of the material development in the project. Major risk in this result is if the used parameters in simulation are not practical, but this could be dealt by doing sensitivity analysis.
List of Websites:
www.aerocoins.eu
1 FUNDACION TECNALIA RESEARCH & INNOVATION Spain
Dr. Eunate Goiti
eunate.goiti@tecnalia.com
2 ASSOCIATION POUR LA RECHERCHE ET LE DEVELOPPEMENT DES METHODES ET PROCESSUS INDUSTRIELS - ARMINES France
Dr. Arnaud Rigacci
arnaud.rigacci@mines-paristech.fr
3 EIDGENOESSISCHE MATERIALPRUEFUNGS- UND FORSCHUNGSANSTALT EMPA Switzerland
Dr. Matthias Koebel
matthias.koebel@empa.ch
4 TEKNOLOGIAN TUTKIMUSKESKUS VTT Finland
Dr. Markku Leivo
Markku.Leivo@vtt.fi
5 POLITECHNIKA LODZKA TUL Poland
Dr. Zdzisław Pakowski
zdzislaw.pakowski@p.lodz.pl
6 BAYERISCHES ZENTRUM FUR ANGEWANDTEENERGIEFORSCHUNG ZAE EV Germany
Dr. Gudrun Reichenauer
Gudrun.Reichenauer@zae-bayern.de
7 PRODUITS CHIMIQUES AUXILIAIRES ET DE SYNTHESE SA France
Dr. Pierre-Andre Marchal
pierre-andre.marchal@pcas.com
8 SEPAREX SA France
Dr. Eric Francais
efrancais@separex.fr
9 ACCIONA INFRAESTRUCTURAS S.A. Spain
Ms. Ewa Zukowska
ewaalicja.zukowska@acciona.com
