Final Report Summary - HYDROBOND (New cost/effective superHYDROphobic coatings with enhanced BOND strengh and wear resistance for application in large wind turbine blades.)
Executive Summary:
Over the past twenty years, there has been a great deal of effort connected to the design of wind turbines, control systems, and energy storage systems to enable wind generation to be used in remote or hybrid power applications. The driving force behind the HYDROBOND project is the need for a step-wise acceleration of wind turbines for cold climate applications.
The HYDDROBOND consortium aims to achieve a variety of benefits with the development of a new coating/paint:
• As a passive anti-icing method the hydrophobic coating enable the development oflarger and lighter turbines, as there is no requirement for alternative, heavy de-icing systems.
• The minimization of ice accretion increase the reliability and operational life of components by reducing mechanical failures caused by ice loading on the turbine blades.
• The cost/efficiency ratio of blades increased due to the avoidance of ice affecting the aerodynamic properties of blades which can result in power losses.
• Enhanced bond strength enable the blades to retain anti-icing properties even when wearing occurs, which will reduce maintenance costs, and as it is a portable solution, in-situ repairs will also be possible. This is particularly important for the offshore market, where maintenance can be extremely expensive and time-consuming.
As a summarythe project activities were focused on feedstock and coating development through different technologies. Optimization procedures for both raw materials and coating technologies have been carried out in the R&D period of the project. A highly innovative process for the application of superhydrophobic coatings onto large on/off-shore turbine blades was developed during the industrialization work package in the last year of the project.
Coatings/paints with tailored anti-icing properties and enhanced bond strength have now been produced Atomic-scale simulations (molecular dynamics) have been considered to investigate the interactions between water and the developed coatings. On the other hand, two new tests have been developed inside the project to account for the different type of exposures of the blades. A jet erosion test and a centrifugal ice adhesion test have been set up due to the pivotal role played within the project by these newly-developed test apparatus.
A novel European Patent (EP17151460) was submitted in February 2017 with the title of: Process for obtaining a dense superhydrophobic or hydrophobic, icephobic and wear resistant coating by means of Cold Gas Spray technique.
The invention relates to a process of production of a dense superhydrophobic or hydrophobic, icephobic and wear resistant coating by means of Cold Gas Spray technique, to the coatings obtained by said process, its use as coating in wind turbine blades, to a wind turbine blade comprising said coatings. Furthermore, the invention relates to the uses of said coatings as anti-fouling coatings, as self-cleaning architecture and as aircraft coatings, as well as the uses in the manufacture of civil engineering or machinery pieces and car, train or truck parts.
Project Context and Objectives:
HYDROBOND project has developed hydrophobic coating which will act as a passive anti-icing method to minimize ice accretion. This PROJECT outlines the development of a highly innovative process for application of SUPERHYDROPHOBIC coatings onto large turbine blades, with the aim of providing step-wise advancement in wind turbine performance, long term operation in icing, and humid environments, wear improving, significantly reducing manufacturing time/costs, flexible scalability of application and reduced environmental impact.
The main objective of Hydrobond project has been to obtain multifunctional properties on windblade surface. To combine hydrophobicity, anti-icing and wear resistance was a challenge from the beginning of project since in the world market there is no material that complies with the multifunctionality of the three properties.
The scope and marketing routes of the project are underlined through the following aspects:
- POWDERS/RESINS/SOL GEL/AEROSOL DEVELOPMENT
- SUPERHYDROPHOBIC, ICEPHOBIC & DURABLE COATINGS/HYBRIDS
- ICE ADHESION & JET EROSION STANDARDIZATION
- WEAR RESISTANCE LEADING EDGE COATINGS/HYBRIDS
- NEW GENERATION OF WIND TURBINE BLADES COATED/PAINTED
- NEW NICHES OF APPLICATION OF SUPERHYDROPHOBIC COATED/PAINTED SURFACES
The FIGURE 1 illustrates the four phases of the project:
Phase 1: Development at Laboratory Scale, including recipes development, substrate definition and coating development in small specimens. Also the characterization and modelling activities are considered in this stage. Taking into account all these important issues, the protocols to produce coated wind blades were stablished:
TiO2 and CeO2 powders were chosen as the main oxides for all technologies. Later also SiO2, SiC and ZrO2 were used. Used oxide materials had different particle sizes extending from nano to micron scale. Hybrids and Composite powders base in a polymeric matrix reinforced with ceramic materials were obtained (more than 150 formulations) at large satisfaction for the main objectives of the project.
The aim was to develop a new type of coating to meet the specifications using advanced coating microstructures and application technologies. Special emphasis was given to achieve superhydrophobic-deicing and rain erosion resistance coatings with improved wear resistance as it has been reported earlier that superhydrophobicity decreases ice adhesion greatly. Moreover, specific focus was on Cold Gas Spraying (CGS), Suspension Liquid Flame Spraying (SLFS) and paint technology using nanostructured materials. New type of materials was developed for each technology.
The developed coatings were compared to commercial solutions and as a main conclusion of each one and after the optimisation process, two recipes for hybrids and one for coatings have been chosen for the scaling up step of the project. All them are base in a composite formulation with nanoceramic reinforce of a fluoropolymer matrix.
The selected hybrid paints present excellent results in ice-adhesion (around 30 kPa), much below the benchmark materials, hydrophobic behaviour, good abrasion resistance, no colour change after UV treatment, excellent sand erosion resistance and good performance in the jet erosion test which can be improved by growing the coating a bit thicker.
On the other hand, the selected CGS powder shows excellent resistance to UV treatment, to abrasion and to the jet erosion test. It is also worth mentioning their hydrophobic behaviour even after the UV treatment. The intrinsic properties of this CGS coating, the easiness for these coatings to grow them thicker as well as the possibility to repair them on site makes them very interesting for Industrial application.
However the good results with the SLFS obtained coatings at the level of superhydrophobicity and low ice-adhesion and also the fact that there are very thinness have been determinate to be use de-icing specifically applications but not in the blades.
In TABLE I (attached to this section) the results of characterization of the final coatings are summarized.
In this phase, two specific testing units were designed in the project to test in laboratory conditions the new developed coatings. The two testing units (FIGURE2) were developed to evaluate resistance to water erosion and ice-adhesion.
Phase 2: Development at Industrial Scale, including the up-scaling of processes and protocols.
In this phase, the industrialization stage began to use the process protocol for the production of test parts with a more complicated shape. Industrial applications like for example wind blades usually show a curved surface geometry in which the spray conditions may differ from the ideal case of a flat substrate. While parameters like gas temperature, pressure and powder feed rate can be translated directly from laboratory spray tests to industrial spraying, other parameters may not. These are for example deviations in impact conditions (impact angle and distance from nozzle), gas flows at sharp edges of the coating area and substrate temperature depending on size and thermal properties of the workpiece. Apart from that, effects of longer spray times on the spray equipment will not show in usually short laboratory spray tests. For these reasons, adjustments of the process protocol may be necessary when transferring laboratory results into industrial application.
Phase 3: Final validation, including extra-test to evaluate the developed coating.
As a first step to real application of the newly developed coatings, the industrial deposition was validated with the performance of standard samples used for rain erosion tests. In wind energy sector, this test is a severe erosion test for paints of commercial blades and was used as a benchmark test for the application of Hydrobond coatings on the leading edge of wind rotor blades.
The production of coatings on these test parts (RE-samples) are shown in FIGURE 3 and the solutions to be tested have to follow this roadmap:
1- Eligibility tests completed
2- JE Test Coupons manufacturing
3- JE test Coupons Validation
a. Defect criteria
b. CGS must comply the thickness requirement
c. Hybrid coupons have to be performed using the same process validated in the point 1.
4- Perform JE test
5- RE Test Coupons manufacturing upon JE successful result (>15h at 1000rpm)
6- RE test Coupons Validation
a. Defect criteria
b. CGS must comply the thickness requirement
c. Hybrid coupons have to be performed using the same process validated in the point
7- Perform RE test
In TABLE II are shown the requirements completed prior to perform the Rain Erosion (RE) test for any new solution.
Phase 4: Final product, including all issues relative to wind market
As proof of concept, one of partnership of project bought a couple of Wind Generators Bonus 450/37 and additionally 6 wind blades model LM17.0 (FIGURE 4) were acquired in order to be able to test survival ability of the solution in a harsh environment in Bremerhaven (Denmark).
After all the testing was carried out to validate the good-application of solutions, the main conclusion of this phase was to select two different Hybrids (HBH070 and HBH079, internal references) to evaluate the readiness of the solutions developed within Hydrobond. HBH079 was not accepted for windblade industry but will be used for other industrial sector applications and finally, although some problems were detected in the application of HBH070 system, it was the solution selected to paint the real blades.
Three windblades were painted in April 2017 (FIGURE 5) for performance comparison between both generators and during May 2017 is expected to start the commissioning and installation in the mills in Bremerhaven. The results of this performance will immediately position one of the Hydrobond solutions in the market. These results will be available by the end of winter 2017.
Project Results:
The main result of Hydrobond project has been to obtain multifunctional properties on windblade surface. To combine hydrophobicity, anti-icing and wear resistance was a challenge from the beginning of project since in the world market there is no material that complies with the multifunctionality of the three properties.
The results get in the HYDROBOND project do possible the substitution of the so-called active anti-icing processes which eliminate ice from the blades by heating specific parts thereof by electrothermal surface heating or by preheating hot air circulation by a passive systems. In fact the coatings / paints obtained in the project act like passive systems since they are constantly avoiding the formation of the ice. This results in a double advantage since we diminish the weight of the blades that in a turbine (with blades of 70 meters) is estimated around 900kg and in term of energy saving that is estimated in 35% of the energy generated by the turbine in operation. On the other hand the active systems needs a constant maintenance and, of course, costly depending on where the turbines are located, against the passive process solution provided by HYDROBOND which ensures a constant maintenance.
Hydrobond results can do lighter blades, decreasing the operational and maintenance cost and improve the energy savings and the energy produce.
This document includes the results of the Hydrobond project summarized taken into account the milestones achieved along the project:
Milestone 1: HYDROBOND, Experimental & Technical Strategies
Three main objectives which have composed the strategy of the project:
- Improve EROSION and ICING behaviour through the development of new coatings on the blades. Specific requirements have been compiled during the project.
- Developing innovative coatings including:
- Design of superhydofobic raw materials. In this first step of the project, TiO2 and CeO2 will be developed but finally a wide range of different composites recipes has been produced.
- Development of agglomerated nanophased powders suitable for spraying. Materials with low surface energy polymer-based materials (belonging to either fluoropolymers or silanes and fluorosilanes) have been tested.
- Modelling of coating-substrate system related to hydrophobicity behaviour
- Validation of the developed and selected coatings with the idea to avoid the needs of heavier active anti-icing methods
- Optimized spray depositions using Cold Gas Spray, Liquid Flame Spray, Sol-Gel and Paint Spray technologies
- Optimized in tailored superhydrophobic characteristics that allow increasing the operational availability of wind turbines.
- Deposition efficiency optimization.
- Comparison with conventional thermal spray processes. Making benchmark coatings using others technologies.
Milestone 2 and 3: Laboratory and large trials
Laboratory trials to be used as substrates were defined by end user MUEHLHAN (MUDK) and consist of a Glass Fibre Reinforce Polymeric Matrix (GFRPM).
The composite is covered by a gelcoat layer ≈30 μm thick. The layer consists of a polymeric matrix containing inorganic fillers (≈15 – 20 vol.%). The composite contains alternating glass fibre layers in a polymer matrix with small but visible distributed porosity (see figure7).
Aluminum light alloys such as A7075-T6 have also been selected for complementary applications to blades in the wind energy sector in other major industrial sectors.
Large trials to be coated as prototypes were defined as 1mx1m samples. They were used to validate the process in terms of productivity in order to calculate the cost of developed product.
Also the trials required in rain erosion (RE) test have been considered as large trials. The figure 3B shows a RE trials.
Milestone 4: Validation of Powders, Hybrids, Coatings and Paints on blade substrates
Based on the expertise knowledge of the Consortium members, TiO2 and CeO2 powders were chosen as the main oxides for all technologies. Later also SiO2, SiC and ZrO2 were used.
Used oxide materials had different particle sizes extending from nano to micron scale. Hybrids and Composite powders base in a polymeric matrix reinforced with ceramic materials were obtained (more than 150 formulations) at large satisfaction for the main objectives of the project.
The aim was to develop a new type of coating to meet the specifications using advanced coating microstructures and application technologies. Special emphasis was given to achieve superhydrophobic-deicing and rain erosion resistance coatings with improved wear resistance as it has been reported earlier that superhydrophobicity decreases ice adhesion greatly. Moreover, specific focus was on Cold Gas Spraying (CGS), Suspension Liquid Flame Spraying (SLFS) and paint technology using nanostructured materials. New type of materials was developed for each technology.
The developed coatings were compared to commercial solutions and as a main conclusion of each one and after the optimisation process, two recipes for hybrids and one for coatings have been chosen for the scaling up step of the project. All them are base in a composite formulation with nanoceramic reinforce of a fluoropolymer matrix.
The selected hybrid paints present excellent results in ice-adhesion (around 30 kPa), much below the benchmark materials, hydrophobic behaviour, good abrasion resistance, no colour change after UV treatment, excellent sand erosion resistance and good performance in the jet erosion testwhich can be improved by growing the coating a bit thicker.
On the other hand, the selected CGS powder shows excellent resistance to UV treatment, to abrasion and to the jet erosion test. It is also worth mentioning their hydrophobic behaviour even after the UV treatment. The intrinsic properties of this CGS coating, the easiness for these coatings to grow them thicker as well as the possibility to repair them on site makes them very interesting for Industrial application.
Although good results were obtained with the SLFS coatings at the level of superhydrophobicity and low ice-adhesion and also the fact that there are very thin have been conlusive to not use de-icing systems in the blades.
Milestone 5: Thermomechanical models and simulations
The modelling and simulation of the blade/coating system was considered at two different scale levels:
- Modelling at the microscale level of the thermomechanical properties of the blade/coating system.
On the one hand, microscale-models were studied in order to simulate the thermomechanical behaviour of coated wind turbine blades. Particular focus is placed onto the distribution of stresses across the coating systems, identifying possible sources of failure and expected crack propagation paths under a variety of loading conditions which simulate both the conditions of the laboratory tests performed and the actual service conditions, such as those encountered in field tests and demonstrations. The figure 8 shows a multi-scale modelling of microstructure optimisation.
- Modelling at the atomistic level of the superhydrophobic properties of the coatings. The atomistic level simulations were carried out using computer simulation techniques such as molecular dynamics (MD). MD simulations allowed analysing in detail the atomistic structure of the super-hydrophobic coating or nanoparticles in order to define the presence of structural peculiarities that could be involved into the hydrophobic behaviour of the final device (Figure 9).
In the figure 9 the best approach to increase the hydrophobicity is to reduce the surface density without increasing the surface porosity to the water molecules.
Milestone 7: Specific simulation testing units
Two testing units were developed, to evaluate resistance to water erosion and ice-adhesion, inside to the HYDROBOND project:
- Jet erosion equipment (JE)
The jet erosion test, developed by UB-CPT, is based in the use of water jets to erode a sample by repeated impact.
Although this equipment uses a jet of water instated of water droplets.
The developed equipment base on (ASTMG73-10) consists of a mechanical system which is based in a whirling arm that rotates at high speed thanks to an electric engine situated under the chamber where the experiment takes place. On the other hand, it has a pump pressure in order to create a water column inside the chamber. Finally, the sample will go at one end of the whirling arm. Once the machine is working, the samples repeatedly impact with the water jets thanks to the rotation of the whirling arm.
Jet Erosion is a very interesting system to be introduced at the industrial level. This testdevice takes into account some aspects, as substrate type or coating thickness, that are not considered in the industrial Rain Erosion (RE) test.
This fact is a clear difference between both tests and can give an advantage to the test developed in the project to understand the scientific-technical limitations. Besides, jet erosion is by far less expensive, it is estimated around 500 € /test in JE compared to the 5000€/ test in Rain Erosion test. The figure 10 shows the HYDROBOND JE equipment.
- Ice adhesion equipment
The ice adhesion measurement, developed by TUT, is carried out in two different steps. The first step is ice-formation and a specific unit was designed to create different types of ice to simulate natural icing conditions.
Ice is deposited onto specially prepared substrates. The second step is the measurement of ice adhesion through the measurement of the necessary centrifugal force to detach the ice-block from the sample.
The figure 11 shows the HYDROBOND icing wind tunnel at TUT and accreted ice on the sample and centrifugal ice adhesion test equipment.
Remark that in both cases, modelling studies of test performance were carried out to evaluate the interest of equipments.
Milestone 6: Validation of the computational procedures
As main conclusions from the modelling and simulation works:
•The centrifugal adhesion test (CAT) was validated as a means to compare quantitatively the ice adhesion onto different surfaces:
- Failure is adhesive rather than cohesive.
- Shear and normal stresses concentrate at the inner edge, yet the analytical interface shear stress is a reliable estimate of the actual, average shear stress and provides a comparative measure of ice adhesion.
- Indications on preferred test set-ups, concerning e.g. the need for a sharp ice block and for a stiff beam setup (not to introduce additional stress terms) were obtained.
•Jet erosion/JE (As a new HYDROBOND approach to test the rain erosion effect) can be used as an accelerated test for fast screening purposes
- It stresses the entire coating+substrate system; hence, it reveals cohesion/adhesion and brittleness issues.
- It can be accelerates by increasing the velocity, but exaggerate values must be avoided.
- It is not a replacement for drop erosion.
•Simulations also revealed that care would be needed in case it is necessary to compare materials with significantly different mechanical behaviours (e.g.: soft viscoelastic vs. harder elastoplastic materials).
•Modelling has proven to be a useful tool to assist and guide both the design and selection of candidate materials, and the set-up of simulated test procedures.
•Multi-scale modelling of thermomechanical and chemical properties of coatings was achieved within expected time schedule and provided important materials design indications that have been followed to yield the presently identified solutions for scaling-up and field testing.
•Micro-mechanical simulation was achieved within expected time schedule and provided important indications on the set-up, use and significance of simulated test-rig procedures.
•HYDROBOND defined a procedure to investigate the relation between surface morphologies, densities, and hydrophobicity of new developed coatings.
•HYDROBOND defined a protocol to investigate the interaction between small polymer chains and solid reinforcement particles.
•HYDROBOND procedure could be a useful screening test of new coating-mixtures
Milestone 8: Coating/paint deposition protocols and industrialization
The development of the coatings in the research part of the project focused on optimal coating properties. In these optimization steps, flat test parts were chosen to find the optimal spray parameters and to perform a variety of laboratory analyses. Flat surfaces are ideally to coat because the impact angle of the sprayed particles as well as the spray distance can be controlled in narrow limits. Different pre- and post-treatment steps can be tested under well-defined conditions and compared with respect to each other to find the optimum way to achieve a high coating quality.
The outcome of this optimization was a process protocol in which the different pre- and post-treatment steps were listed and the optimal spray conditions were defined.
In the figure12, panels come from and old LM17.0 blade used during test campaign, after coating trials
While as hybrid process does not differ from that for coating in laboratory samples, the LP-CGS process needs an improving in the up-scaling procedure relative to post-deposition stage. Concerning the CGS coatings, a protocol base in a European Patent was done:
EP17151460. 13 JANUARY 2017: Process for obtaining a dense superhydrophobic or hydrophobic, icephobic and wear resistant coating by means of Cold Gas Spray technique.
The invention relates to a process of production of a dense superhydrophobic or hydrophobic, icephobic and wear resistant coating by means of Cold Gas Spray technique, to the coatings obtained by said process, its use as coating in wind turbine blades, to a wind turbine blade comprising said coatings. Furthermore, the invention relates to the uses of said coatings as anti-fouling coatings, as self-cleaning architecture and as aircraft coatings, as well as the uses in the manufacture of civil engineering or machinery pieces and car, train or truck parts.
The invention related to a process for obtaining a dense and multifunctional properties coatings onto a substrate characterized in that it comprises the steps included in the scheme of the global process as the figure 13 shows:
From the industrial point of view, this post-deposition process for coatings consolidation needs considered to achieve to the thickness reduction target. Autoclave treatment processes have been considered to achieve the thickness reduction target at satisfaction because in function of the P and T parameters a significant change of coating thickness of 35% is compliance.
The figure 14 shows the effect of the thermomechanical post-treatment on the coating microstructure (cross-section, optical microscopy, before and after P/T Treatment)
Milestone9: Potential benefits establishment to increasing the wind EU Market
The potential benefits of project result are focus on Icephobic coatings. This market includes various transportation applications, all arctic – especially off-shore – building and energy applications and also heat exchangers and cooling applications
The hybrid coatings developed in HYDROBOND project show high durability in outdoor applications, low ice adhesion and good wear resistance. They can be applied using regular paint technology and can be adjusted for color and gloss according to customer demand. However, they do not prevent ice formation but ease ice detachment clearly compared to existing outdoor paints. Thus they have lot of application potential in many industries
The cold gas sprayed coatings (CGS) show promising wear resistance reaching 3 hours without erosion in RE test and 13hours in Jet Erosion test (ASTMG73-10) . The possibility of using CGS technology on an industrial level with autoclave post mechanical- heat treatment is promising both in the Wind Energy sector at the level of other smaller pieces and with metallic substrates and its extension is valuable in other fields
Milestone 10: Reduced scale wind blade prototype coated with new durable Superhydrophobic coatings
From the multiple technical tests conclusions are:
1.- Hybrids: Suitable Hybrids for industrialisation have been identified.
Other Hybrids have lower values in the RE test, however, these coatings seem good
candidates for other applications (bridges, cars, aeronautic,...) and have to be evaluated.
2.- CGS coatings: The last specimen has passed 10 hours in RE test and this is really good but for
large blades the CGS+autoclave treatment needs to be improved. However for small blades are factible and need to be test in industrial conditions following the protocol of the mentioned patent the same as for other type of applications.
From rain erosion (RE) test, the highest coating quality is reached by a combination of the coating application and a thermo-mechanical post-treatment of LP-CGS process but the difficulty to industrialize the post-treatment has caused that the real scaled blade prototype had to be the hybrid solution system.
Final Application
Muehlhan adquired a couple of Wind Generators Bonus 450/37 and additionally 6 wind blades model LM17.0 (Figure 4) have been acquired in orderto test survival ability???? of the solution in a harsh environment in Bremerhaven (Denmark).
Three windblades are in process to be painted for performance comparison between both generators. The results of this performance will immediately position one of the Hydrobond solutions in the market.No habría que añadir algo más de información aqui??? Queda un poco ligerito no?
Icephobic coatings market
The hybrid coatings and the CGS coatings developed in HYDROBOND project show multidisciplinary properties and particularly, Super-Hydrophobicity, low ice adhesion and good wear/rain erosion resistance. They can be applied using regular paint technology and also in coatings after the consolidation processes and they have lot of application potential in many industries
Icephobic coatings market includes various transportation applications, all arctic – especially off-shore – building and energy applications and also heat exchangers and cooling applications among others:
Off-shore structures
Off-shore industry includes oil and gas industry besides wind energy. Sea water sprays form ice on structures causing work hazards and machinery malfunctions. Icephobic coatings could decrease the amount of ice and ease its removal.
Marine industry
Ships that operate in arctic conditions suffer from ice accretion into structures. This creates working hazards and even unbalance to ship’s behaviour. Also deck machinery may be not usable due to ice formation. They are usually removed by mechanical hammering, steam or even electrical heating.
Aeronautic Industry
Icing has long been a critical issue in Aviation, not only a performance-affecting issue, but more so one compromising safety. Accidents due to ice accumulating in various parts of the aircraft are still today one of the main concerns of aviation safety authorities. It is for this reason that a parallel scenario could be envisaged, for the potential applications in the aviation sector of solutions found within the Hydrobond project for the Wind Turbine Industry.
Automotive Sector
Superhydrophobic solutions (Hydrobond results) could help increase the product life of car motors and body work as well as improving aesthetical aspects of appearance. Etos project was developed during last year in Germany (Putzier as a member of the project has a participation and contribution) and some solutions from Hydrobond were tested.
Ice and snow formation on antennas
Snow and ice accretion on antennas may deteriorate the reception of a broadcast. Loss of signals may happen while snow is melting: water film forming on antenna surface attenuates reception signals. The snow and ice accretion also increases the weight of the equipment, which may cause breakage or destruction. It is essential to prevent the snow or ice accretion from forming to protect equipment and structures.
Other Applications (Figure 15)
As a relationship of possible applications of the HYDROBOND products here there is a list other specific fields:
• Bridges (Cables, Railings) • Communication Towers
• Power Lines • Guy Wires
• Cables • Satellite Dishes
• Microwave Domes • Overpasses
• Elevated Walkways • Roof Edges
• Train Cars • Cars and truck
Potential Impact:
It is well known that wind turbines are one of the fastest growing sources of “green” power in the world today. There are now 141.578MW (141.6 GW) installed in EU with a total cumulative capacity of 147.771 MW (147.8 GW) for all of Europe. Wind power installed more than any other form of power generation in 2015, accounting for 44.2% of all power capacity installations.
Over the past twenty years, there has been a great deal of effort connected to the design of wind turbines, control systems, and energy storage systems to enable wind generation to be used in remote or hybrid power applications. The driving force behind the HYDROBOND project is the need for a step-wise acceleration of wind turbines for cold climate applications.
In fact, the overall expected impact of the HYDROBOND project was the reduction of weight of wind turbine blades increasing the reliability and operational life of blades, especially where an anti- and de-icing system (ADIS) is used in cold climate applications, and improving the costs of wind energy by reducing maintenance frequency and stops during their life cycle.
The improvement on cold climate wind energy production due to the implementation of SUPERHYDROPHOBIC coatings to blades could be increased up to 10-20% annually (due anti-icing and de-icing properties among other properties in blades).
According to HYDROBOND estimations more than 30 million tons of CO2 emissions will be reduced during the period 2017-2020 after the implementation of the super hydrophobic coatings developed within the Hydrobond Project. Since lower maintenance will be needed, transport to offshore wind farms will be reduced and hence, marine habitat will be less damaged. Higher efficiency of offshore wind turbines will result in more capacity of power generation and thus, less necessity for onshore wind farms.
Although the project is primarily aimed at the offshore market, the technology can equally be applied to onshor turbines in cold climates, where anti-icing and de-icing properties are essential.
The global superhydrophobic coating market was valued at USD 5.77 million in 2015. Rising demand for consumer electronics with highly water-repellent properties to protect sensitive data & components is a key factor driving market growth. (http://www.grandviewresearch.com/industry-analysis/superhydrophobic-coating-market)
Icephobic coatings are adaptable to a variety of developing applications. The “Hydrophobic Coatings and Surfaces: 2016-2023” report from the NanoMarkets Company n-tech Research projects the market for hydrophobic materials used for self-cleaning, de-icing, anti-fouling and anticorrosion applications will grow to $1.8 billion by 2021.
The above shortly mentioned shows that there is an increasing market and potential to solve ice related problems with advanced icephobic coatings. Aerospace industry has a clear need for decreasing the use of deicing chemicals but due to their costly and long approval process they are not the primary target of the developed coatings. Although the developed hybrid coatings did not pass the rain erosion test they showed excellent outdoor durability and icephobic behavior. Therefore new markets are looked from applications where erosive wear is not primary problem as in wind mill blades. However, outside leading edge, the developed coatings could offer benefits over conventional paints regarding ease of ice formation and detachment of formed ice. Statkraft has shown interest in testing icephobic coatings in their wind mill farm suffering from icing. The erosion resistance development will continue.
Three main project results have been pointed in term of exploitation:
- Hybrids coatings are showing a promising ice-detachment resistance and also have good ice formation avoidance characteristics. Therefore, they could be potential target for industries exposed to ice formation conditions.
- Cold Gas Spray has initially a big potential, as it could be applied on site without further curing as regular coatings. The opportunity is great but there are some process improvements that need to be overcome in order to provide a solution with positive business case.
- Standardization procedure: Jet erosion test was produced as a new method for rain effect on the substrates.
- During all the four years of the Project the consortium has been evaluated the full spectrum of exploitation and dissemination opportunities, including protecting the results through patents and IPR agreements.
Besides wind mills the main focus will be in offering the hybrid coating products for marine, transportation and construction industry and their service and subcontractor companies. The individual specifications will be verified and coatings modified to meet the demands.
Trains suffer from delays in winter conditions due to snow and ice. HYDROBOND developed icephobic coating technology is being tested in train cars in Finnish railways. Also the coatings developed in the HYDROBOND project will be offered for the subcontractors offering products for oil and gas industry.
During the Hydrobond project, some objectives from the point of view of dissemination have been achieved:
• Creating HYDROBOND web, Hydrobond website (www.hydro-bond.eu) was very dynamic in terms of news relatives to wind sector, and the consortium keep an intranet space where the partners share information, documents and also the meeting agendas and minutes.
• Link the Hydrobond webpage in the web sites of each partner.
•Referencing of HYDROBOND project in seminars and workshops & joining international conferences
Hydrobond partners have been present in different exhibitions from the wind energy sector, i.e.
► Winter Wind Energy Conference (Sweden), November 2014.
► EWEA (European Wind Energy Association) Annual Event . May2014 (Barcelona).
► International Thermal Spray Conference and Exhibition. June 2014 (Barcelona).
► EWEA OFFSHORE 2015 (Denmark).
► International Thermal Spray Conference and Exhibition .May 2015 (USA).
► 1st Innovation Workshop on Cold Gas Spray Technology. June 2015 (Spain).
► MATERIAIS, Porto, June 2015 (Portugal).
► International Conference European Ceramic Society: ECerS XIV (Spain2015).
► International Workshop on Atmospheric Icing of Structures (Sweden) 2015.
► Husum Wind 2015 (Germany).
► EWEA 2015. November 2015 (France).
► 2nd International Conference Offshore Substructures. February 2016. London UK.
► International Thermal Spray Conference, Shanghai, China, May 2016.
► EWEA 2016. Hamburg Messe. Sep 2016 .Germany.
Hydrobond was also presented in the 1st Workshop and General Assembly of the Engineering & Upscaling Cluster (12th February 2015, Brussels).
HYDROBOND consortium was very active belong of these years and also we don’t forget that all partners has been active in meetings of the consortium. In the following table, the different meetings are reported:
HYDROBOND MEETINGS
2013. Barcelona. Kick off meeting (31st January-1st February)
2013. Tampere. 6 month meeting (27th -28th June)
2014. Brussels. 12 month meeting (30th-31st January)
2014. Modena. 18 month meeting (26th-27th June)
2014 Barcelona. 21 month meeting (23rd October)
2015. Pamplona. 25 month meeting (5th-6th February)
2015. Teleconference. 29 month meeting (19th May)
2015. Helsinki. 30 month meeting (29th June)
2015. Paris. 35 month meeting (18th-19th November)
2016. Barcelona. Industrial meeting (8th January)
2016. Brussels. 38 moth meeting (4th-5th February)
2016. Teleconferences 19th April; 5th May; 19th May; 31st May; 28th June;
18th July; 4th October; 19th October; 7th & 23rd November;1st December
2016. Barcelona. 44 month meeting (12th-13rd September)
2016. Barcelona. International Network & Technical Meeting (21st-22rd & 23th November)
2017. Brussels. Final meeting (16th-17th January)
In November 2015 in occasion of the International EWEA meeting and exhibition held in Paris, Prof. Guilemany (coordinator of Hydrobond project) and the Project Management Cluster, besides technical and administrative activities has proposed to the exploitation and dissemination board the organization of an International Workshop in order to pool results and experiences between different European projects related to the WIND ENERGY sector. After consultation with the Programme Officer and PTA of the HYDROBOND project, the event was scheduled on November 2016 and the participation of the others granted EU projects was confirmed (Figure 17), with the following main objectives:
1. Bring Industry and science closer presenting challenges, ideas, methods and capabilities.
2. Having Wind Turbine owners addressing some of the major challenges operating windfarms.
3. Introduce the different European Projects related to WIND TURBINE Industry for sharing experiences in addressing the challenges in this sector.
4. Give industrial partners the possibilities to meet the scientific partners to present capabilities in each segment
5. Interaction between Industry Expert speakers presentations in conference and workshopping to get deep understanding of challenges and concepts
6. Finding new partners for new projects
7. Networking across the disciplines and among the participants.
With the participation of European projects:
ACORN : “Advanced Coatings for Offshore Renewable Energy”
JEDI- ACE: “Japanese-European De-Icing Aircraft Collaborative Exploration”
SUPRAPOWER: “SUPerconducting, Reliable, lightweight, And more POWERful offshore wind turbine”
ECOSWING: “Energy Cost Optimization using Superconducting Wind Generators - World’s First Demonstration of a 3.6 MW Low-Cost Lightweight DD Superconducting Generator on a Wind Turbine”
WALID: “Wind Blade Using Cost-Effective Advanced Composite Lightweight Design.”
NANOLEAP: “Nanocomposite for building constructions and civil infrastructures: European network pilot production line to promote industrial application cases.”
RIBLET4WIND: “ Riblet-Surfaces for Improvement of Efficiency of Wind Turbines”
LIBI: “Optimal Lightning Protection System.”
MARE-WINT: “New Materials and Reliability in offshore WINd Turbines Technology.“
DASHWIN: “ Development of Advanced Shearography System for On-Site Inspection of Wind Turbine Blades”
HYDROBOND: “New Cost/Effective Superhydrophobic Coatings with Enhanced Bond Strength and Wear Resistance for Application in Large Wind Turbine Blades“.
CL-Windcon: “Developing the next generation technologies of renewable electricity and heating/cooling”
During two days, 21st and 22nd of November, in Barcelona (Hotel Rey Don Jaime, Castelldefelds), the International Workshop took place with different activities related to the wind energy sector.
The coordinators of the EU sponsoring projects participated in the event showing the main results of the projects involved. More than 80 participants from industrial and academic sector from 14 different European countries joined in this forum.
According to the above, we obtain a series of issues that as a general conclusion are summarized in the following keywords and that should be developed / undertaken in future actions at European financial support level:
Keywords 1: The future wind blades should be maintenance-free
Keywords 2: Lack of engineers specialized in wind energy
Keywords 3: Change in industrial fabrication processes is required.
A special attention should be given to the introduction of new, modern and smart technologies:
New sensors for monitoring the degradation of materials in wind turbines
New algorithms for control
Application of additive manufacturing technologies
Self-healing materials
New technologies for predictive maintenance
New technologies for onsite repairing
New manufacturing processes, automatization, standardization, economies of scale
The coordinators of all 12 European Projects take the responsibility to produce a document at beginning of January 2017 as preliminary draft in order to be approved for all the consortiums before the end of March 2017.
Detailed descriptions of the conclusions of this workshop were distributed inside to the EU for Wind Energy and Renewable energies using the facilities of our Programme Officer linked to HYDROBOND (Figure 18).
During the beginning of the project the consortium has evaluated the patenting the results of the project and concerning the CGS coatings a protocol base in a European Patent was done:
EP17151460. 13 JANUARY 2017: Process for obtaining a dense superhydrophobic or hydrophobic, icephobic and wear resistant coating by means of Cold Gas Spray technique.
The invention relates to a process of obtainment of a dense superhydrophobic or hydrophobic, icephobic and wear resistant coating by means of Cold Gas Spray technique, to the coatings obtained by said process, its use as coating in wind turbine blades, to a wind turbine blade comprising said coatings. Furthermore, the invention relates to the uses of said coatings as anti-fouling coatings, as self-cleaning architecture and as aircraft coatings, as well as the uses in the manufacture of civil engineering or machinery pieces and car, train or truck parts.
This is one of the reasons why today the most relevant results have not yet been published because patenting the results of the project was always under serious consideration
However two dissemination papers where authorized by the consortium concerning a noncritical secrecy results:
1. Winterwind conference (6-8 February, 2017, Skellefteå, Sweden); Figure 19
2. International Workshop on Atmospheric Icing Structures (28June-3July, Uppsala, Sweden, 2015). Figure 20
Dissemination will be continued through different ways and also the HYDROBOND website will be active during two years after the project finishing.
The main actions inside to the Exploitation were:
•To explore the commercialization of products developed in the project (powder/resins/hybrids/coatings).
•To contact with other application interested in anti-icing behaviour. Millidyne has some business companies interested with the transport sector
•LM (Danish Blade Manufacturing Company) collaboration. LM offers two turbine (has bought by MUDK) placed very close to shore with 6 blades that were coated with the HYDROBOND solution on April 2017.
•Other application in transport sector, like decoration as KE showed in Etos project (supported by Putzier).
•To explore the commercialization of products developed in the project inside to the Blade Damage and Repair industrial sector.
•To explore the commercialization of an specific testing protocol (standardization) and a new Device, the Jet Erosion Test, has been built up to evaluate the resistance to water abrasion of the coatings to simulate blades in real working conditions. The Jet Erosion Test, have been carried out by editing a video shown presented in the Brussels meeting (5th of February 2016) to show the facility and the potential benefit of the test to the wind turbine industry. This video is today available in YouTube since April 2016:
https://www.youtube.com/watch?v=A9eO6rwHwjs
List of Websites:
www.hydro-bond.eu
www.cptub.com
c/ Marti i Franques, 1
Barcelona 08028
Over the past twenty years, there has been a great deal of effort connected to the design of wind turbines, control systems, and energy storage systems to enable wind generation to be used in remote or hybrid power applications. The driving force behind the HYDROBOND project is the need for a step-wise acceleration of wind turbines for cold climate applications.
The HYDDROBOND consortium aims to achieve a variety of benefits with the development of a new coating/paint:
• As a passive anti-icing method the hydrophobic coating enable the development oflarger and lighter turbines, as there is no requirement for alternative, heavy de-icing systems.
• The minimization of ice accretion increase the reliability and operational life of components by reducing mechanical failures caused by ice loading on the turbine blades.
• The cost/efficiency ratio of blades increased due to the avoidance of ice affecting the aerodynamic properties of blades which can result in power losses.
• Enhanced bond strength enable the blades to retain anti-icing properties even when wearing occurs, which will reduce maintenance costs, and as it is a portable solution, in-situ repairs will also be possible. This is particularly important for the offshore market, where maintenance can be extremely expensive and time-consuming.
As a summarythe project activities were focused on feedstock and coating development through different technologies. Optimization procedures for both raw materials and coating technologies have been carried out in the R&D period of the project. A highly innovative process for the application of superhydrophobic coatings onto large on/off-shore turbine blades was developed during the industrialization work package in the last year of the project.
Coatings/paints with tailored anti-icing properties and enhanced bond strength have now been produced Atomic-scale simulations (molecular dynamics) have been considered to investigate the interactions between water and the developed coatings. On the other hand, two new tests have been developed inside the project to account for the different type of exposures of the blades. A jet erosion test and a centrifugal ice adhesion test have been set up due to the pivotal role played within the project by these newly-developed test apparatus.
A novel European Patent (EP17151460) was submitted in February 2017 with the title of: Process for obtaining a dense superhydrophobic or hydrophobic, icephobic and wear resistant coating by means of Cold Gas Spray technique.
The invention relates to a process of production of a dense superhydrophobic or hydrophobic, icephobic and wear resistant coating by means of Cold Gas Spray technique, to the coatings obtained by said process, its use as coating in wind turbine blades, to a wind turbine blade comprising said coatings. Furthermore, the invention relates to the uses of said coatings as anti-fouling coatings, as self-cleaning architecture and as aircraft coatings, as well as the uses in the manufacture of civil engineering or machinery pieces and car, train or truck parts.
Project Context and Objectives:
HYDROBOND project has developed hydrophobic coating which will act as a passive anti-icing method to minimize ice accretion. This PROJECT outlines the development of a highly innovative process for application of SUPERHYDROPHOBIC coatings onto large turbine blades, with the aim of providing step-wise advancement in wind turbine performance, long term operation in icing, and humid environments, wear improving, significantly reducing manufacturing time/costs, flexible scalability of application and reduced environmental impact.
The main objective of Hydrobond project has been to obtain multifunctional properties on windblade surface. To combine hydrophobicity, anti-icing and wear resistance was a challenge from the beginning of project since in the world market there is no material that complies with the multifunctionality of the three properties.
The scope and marketing routes of the project are underlined through the following aspects:
- POWDERS/RESINS/SOL GEL/AEROSOL DEVELOPMENT
- SUPERHYDROPHOBIC, ICEPHOBIC & DURABLE COATINGS/HYBRIDS
- ICE ADHESION & JET EROSION STANDARDIZATION
- WEAR RESISTANCE LEADING EDGE COATINGS/HYBRIDS
- NEW GENERATION OF WIND TURBINE BLADES COATED/PAINTED
- NEW NICHES OF APPLICATION OF SUPERHYDROPHOBIC COATED/PAINTED SURFACES
The FIGURE 1 illustrates the four phases of the project:
Phase 1: Development at Laboratory Scale, including recipes development, substrate definition and coating development in small specimens. Also the characterization and modelling activities are considered in this stage. Taking into account all these important issues, the protocols to produce coated wind blades were stablished:
TiO2 and CeO2 powders were chosen as the main oxides for all technologies. Later also SiO2, SiC and ZrO2 were used. Used oxide materials had different particle sizes extending from nano to micron scale. Hybrids and Composite powders base in a polymeric matrix reinforced with ceramic materials were obtained (more than 150 formulations) at large satisfaction for the main objectives of the project.
The aim was to develop a new type of coating to meet the specifications using advanced coating microstructures and application technologies. Special emphasis was given to achieve superhydrophobic-deicing and rain erosion resistance coatings with improved wear resistance as it has been reported earlier that superhydrophobicity decreases ice adhesion greatly. Moreover, specific focus was on Cold Gas Spraying (CGS), Suspension Liquid Flame Spraying (SLFS) and paint technology using nanostructured materials. New type of materials was developed for each technology.
The developed coatings were compared to commercial solutions and as a main conclusion of each one and after the optimisation process, two recipes for hybrids and one for coatings have been chosen for the scaling up step of the project. All them are base in a composite formulation with nanoceramic reinforce of a fluoropolymer matrix.
The selected hybrid paints present excellent results in ice-adhesion (around 30 kPa), much below the benchmark materials, hydrophobic behaviour, good abrasion resistance, no colour change after UV treatment, excellent sand erosion resistance and good performance in the jet erosion test which can be improved by growing the coating a bit thicker.
On the other hand, the selected CGS powder shows excellent resistance to UV treatment, to abrasion and to the jet erosion test. It is also worth mentioning their hydrophobic behaviour even after the UV treatment. The intrinsic properties of this CGS coating, the easiness for these coatings to grow them thicker as well as the possibility to repair them on site makes them very interesting for Industrial application.
However the good results with the SLFS obtained coatings at the level of superhydrophobicity and low ice-adhesion and also the fact that there are very thinness have been determinate to be use de-icing specifically applications but not in the blades.
In TABLE I (attached to this section) the results of characterization of the final coatings are summarized.
In this phase, two specific testing units were designed in the project to test in laboratory conditions the new developed coatings. The two testing units (FIGURE2) were developed to evaluate resistance to water erosion and ice-adhesion.
Phase 2: Development at Industrial Scale, including the up-scaling of processes and protocols.
In this phase, the industrialization stage began to use the process protocol for the production of test parts with a more complicated shape. Industrial applications like for example wind blades usually show a curved surface geometry in which the spray conditions may differ from the ideal case of a flat substrate. While parameters like gas temperature, pressure and powder feed rate can be translated directly from laboratory spray tests to industrial spraying, other parameters may not. These are for example deviations in impact conditions (impact angle and distance from nozzle), gas flows at sharp edges of the coating area and substrate temperature depending on size and thermal properties of the workpiece. Apart from that, effects of longer spray times on the spray equipment will not show in usually short laboratory spray tests. For these reasons, adjustments of the process protocol may be necessary when transferring laboratory results into industrial application.
Phase 3: Final validation, including extra-test to evaluate the developed coating.
As a first step to real application of the newly developed coatings, the industrial deposition was validated with the performance of standard samples used for rain erosion tests. In wind energy sector, this test is a severe erosion test for paints of commercial blades and was used as a benchmark test for the application of Hydrobond coatings on the leading edge of wind rotor blades.
The production of coatings on these test parts (RE-samples) are shown in FIGURE 3 and the solutions to be tested have to follow this roadmap:
1- Eligibility tests completed
2- JE Test Coupons manufacturing
3- JE test Coupons Validation
a. Defect criteria
b. CGS must comply the thickness requirement
c. Hybrid coupons have to be performed using the same process validated in the point 1.
4- Perform JE test
5- RE Test Coupons manufacturing upon JE successful result (>15h at 1000rpm)
6- RE test Coupons Validation
a. Defect criteria
b. CGS must comply the thickness requirement
c. Hybrid coupons have to be performed using the same process validated in the point
7- Perform RE test
In TABLE II are shown the requirements completed prior to perform the Rain Erosion (RE) test for any new solution.
Phase 4: Final product, including all issues relative to wind market
As proof of concept, one of partnership of project bought a couple of Wind Generators Bonus 450/37 and additionally 6 wind blades model LM17.0 (FIGURE 4) were acquired in order to be able to test survival ability of the solution in a harsh environment in Bremerhaven (Denmark).
After all the testing was carried out to validate the good-application of solutions, the main conclusion of this phase was to select two different Hybrids (HBH070 and HBH079, internal references) to evaluate the readiness of the solutions developed within Hydrobond. HBH079 was not accepted for windblade industry but will be used for other industrial sector applications and finally, although some problems were detected in the application of HBH070 system, it was the solution selected to paint the real blades.
Three windblades were painted in April 2017 (FIGURE 5) for performance comparison between both generators and during May 2017 is expected to start the commissioning and installation in the mills in Bremerhaven. The results of this performance will immediately position one of the Hydrobond solutions in the market. These results will be available by the end of winter 2017.
Project Results:
The main result of Hydrobond project has been to obtain multifunctional properties on windblade surface. To combine hydrophobicity, anti-icing and wear resistance was a challenge from the beginning of project since in the world market there is no material that complies with the multifunctionality of the three properties.
The results get in the HYDROBOND project do possible the substitution of the so-called active anti-icing processes which eliminate ice from the blades by heating specific parts thereof by electrothermal surface heating or by preheating hot air circulation by a passive systems. In fact the coatings / paints obtained in the project act like passive systems since they are constantly avoiding the formation of the ice. This results in a double advantage since we diminish the weight of the blades that in a turbine (with blades of 70 meters) is estimated around 900kg and in term of energy saving that is estimated in 35% of the energy generated by the turbine in operation. On the other hand the active systems needs a constant maintenance and, of course, costly depending on where the turbines are located, against the passive process solution provided by HYDROBOND which ensures a constant maintenance.
Hydrobond results can do lighter blades, decreasing the operational and maintenance cost and improve the energy savings and the energy produce.
This document includes the results of the Hydrobond project summarized taken into account the milestones achieved along the project:
Milestone 1: HYDROBOND, Experimental & Technical Strategies
Three main objectives which have composed the strategy of the project:
- Improve EROSION and ICING behaviour through the development of new coatings on the blades. Specific requirements have been compiled during the project.
- Developing innovative coatings including:
- Design of superhydofobic raw materials. In this first step of the project, TiO2 and CeO2 will be developed but finally a wide range of different composites recipes has been produced.
- Development of agglomerated nanophased powders suitable for spraying. Materials with low surface energy polymer-based materials (belonging to either fluoropolymers or silanes and fluorosilanes) have been tested.
- Modelling of coating-substrate system related to hydrophobicity behaviour
- Validation of the developed and selected coatings with the idea to avoid the needs of heavier active anti-icing methods
- Optimized spray depositions using Cold Gas Spray, Liquid Flame Spray, Sol-Gel and Paint Spray technologies
- Optimized in tailored superhydrophobic characteristics that allow increasing the operational availability of wind turbines.
- Deposition efficiency optimization.
- Comparison with conventional thermal spray processes. Making benchmark coatings using others technologies.
Milestone 2 and 3: Laboratory and large trials
Laboratory trials to be used as substrates were defined by end user MUEHLHAN (MUDK) and consist of a Glass Fibre Reinforce Polymeric Matrix (GFRPM).
The composite is covered by a gelcoat layer ≈30 μm thick. The layer consists of a polymeric matrix containing inorganic fillers (≈15 – 20 vol.%). The composite contains alternating glass fibre layers in a polymer matrix with small but visible distributed porosity (see figure7).
Aluminum light alloys such as A7075-T6 have also been selected for complementary applications to blades in the wind energy sector in other major industrial sectors.
Large trials to be coated as prototypes were defined as 1mx1m samples. They were used to validate the process in terms of productivity in order to calculate the cost of developed product.
Also the trials required in rain erosion (RE) test have been considered as large trials. The figure 3B shows a RE trials.
Milestone 4: Validation of Powders, Hybrids, Coatings and Paints on blade substrates
Based on the expertise knowledge of the Consortium members, TiO2 and CeO2 powders were chosen as the main oxides for all technologies. Later also SiO2, SiC and ZrO2 were used.
Used oxide materials had different particle sizes extending from nano to micron scale. Hybrids and Composite powders base in a polymeric matrix reinforced with ceramic materials were obtained (more than 150 formulations) at large satisfaction for the main objectives of the project.
The aim was to develop a new type of coating to meet the specifications using advanced coating microstructures and application technologies. Special emphasis was given to achieve superhydrophobic-deicing and rain erosion resistance coatings with improved wear resistance as it has been reported earlier that superhydrophobicity decreases ice adhesion greatly. Moreover, specific focus was on Cold Gas Spraying (CGS), Suspension Liquid Flame Spraying (SLFS) and paint technology using nanostructured materials. New type of materials was developed for each technology.
The developed coatings were compared to commercial solutions and as a main conclusion of each one and after the optimisation process, two recipes for hybrids and one for coatings have been chosen for the scaling up step of the project. All them are base in a composite formulation with nanoceramic reinforce of a fluoropolymer matrix.
The selected hybrid paints present excellent results in ice-adhesion (around 30 kPa), much below the benchmark materials, hydrophobic behaviour, good abrasion resistance, no colour change after UV treatment, excellent sand erosion resistance and good performance in the jet erosion testwhich can be improved by growing the coating a bit thicker.
On the other hand, the selected CGS powder shows excellent resistance to UV treatment, to abrasion and to the jet erosion test. It is also worth mentioning their hydrophobic behaviour even after the UV treatment. The intrinsic properties of this CGS coating, the easiness for these coatings to grow them thicker as well as the possibility to repair them on site makes them very interesting for Industrial application.
Although good results were obtained with the SLFS coatings at the level of superhydrophobicity and low ice-adhesion and also the fact that there are very thin have been conlusive to not use de-icing systems in the blades.
Milestone 5: Thermomechanical models and simulations
The modelling and simulation of the blade/coating system was considered at two different scale levels:
- Modelling at the microscale level of the thermomechanical properties of the blade/coating system.
On the one hand, microscale-models were studied in order to simulate the thermomechanical behaviour of coated wind turbine blades. Particular focus is placed onto the distribution of stresses across the coating systems, identifying possible sources of failure and expected crack propagation paths under a variety of loading conditions which simulate both the conditions of the laboratory tests performed and the actual service conditions, such as those encountered in field tests and demonstrations. The figure 8 shows a multi-scale modelling of microstructure optimisation.
- Modelling at the atomistic level of the superhydrophobic properties of the coatings. The atomistic level simulations were carried out using computer simulation techniques such as molecular dynamics (MD). MD simulations allowed analysing in detail the atomistic structure of the super-hydrophobic coating or nanoparticles in order to define the presence of structural peculiarities that could be involved into the hydrophobic behaviour of the final device (Figure 9).
In the figure 9 the best approach to increase the hydrophobicity is to reduce the surface density without increasing the surface porosity to the water molecules.
Milestone 7: Specific simulation testing units
Two testing units were developed, to evaluate resistance to water erosion and ice-adhesion, inside to the HYDROBOND project:
- Jet erosion equipment (JE)
The jet erosion test, developed by UB-CPT, is based in the use of water jets to erode a sample by repeated impact.
Although this equipment uses a jet of water instated of water droplets.
The developed equipment base on (ASTMG73-10) consists of a mechanical system which is based in a whirling arm that rotates at high speed thanks to an electric engine situated under the chamber where the experiment takes place. On the other hand, it has a pump pressure in order to create a water column inside the chamber. Finally, the sample will go at one end of the whirling arm. Once the machine is working, the samples repeatedly impact with the water jets thanks to the rotation of the whirling arm.
Jet Erosion is a very interesting system to be introduced at the industrial level. This testdevice takes into account some aspects, as substrate type or coating thickness, that are not considered in the industrial Rain Erosion (RE) test.
This fact is a clear difference between both tests and can give an advantage to the test developed in the project to understand the scientific-technical limitations. Besides, jet erosion is by far less expensive, it is estimated around 500 € /test in JE compared to the 5000€/ test in Rain Erosion test. The figure 10 shows the HYDROBOND JE equipment.
- Ice adhesion equipment
The ice adhesion measurement, developed by TUT, is carried out in two different steps. The first step is ice-formation and a specific unit was designed to create different types of ice to simulate natural icing conditions.
Ice is deposited onto specially prepared substrates. The second step is the measurement of ice adhesion through the measurement of the necessary centrifugal force to detach the ice-block from the sample.
The figure 11 shows the HYDROBOND icing wind tunnel at TUT and accreted ice on the sample and centrifugal ice adhesion test equipment.
Remark that in both cases, modelling studies of test performance were carried out to evaluate the interest of equipments.
Milestone 6: Validation of the computational procedures
As main conclusions from the modelling and simulation works:
•The centrifugal adhesion test (CAT) was validated as a means to compare quantitatively the ice adhesion onto different surfaces:
- Failure is adhesive rather than cohesive.
- Shear and normal stresses concentrate at the inner edge, yet the analytical interface shear stress is a reliable estimate of the actual, average shear stress and provides a comparative measure of ice adhesion.
- Indications on preferred test set-ups, concerning e.g. the need for a sharp ice block and for a stiff beam setup (not to introduce additional stress terms) were obtained.
•Jet erosion/JE (As a new HYDROBOND approach to test the rain erosion effect) can be used as an accelerated test for fast screening purposes
- It stresses the entire coating+substrate system; hence, it reveals cohesion/adhesion and brittleness issues.
- It can be accelerates by increasing the velocity, but exaggerate values must be avoided.
- It is not a replacement for drop erosion.
•Simulations also revealed that care would be needed in case it is necessary to compare materials with significantly different mechanical behaviours (e.g.: soft viscoelastic vs. harder elastoplastic materials).
•Modelling has proven to be a useful tool to assist and guide both the design and selection of candidate materials, and the set-up of simulated test procedures.
•Multi-scale modelling of thermomechanical and chemical properties of coatings was achieved within expected time schedule and provided important materials design indications that have been followed to yield the presently identified solutions for scaling-up and field testing.
•Micro-mechanical simulation was achieved within expected time schedule and provided important indications on the set-up, use and significance of simulated test-rig procedures.
•HYDROBOND defined a procedure to investigate the relation between surface morphologies, densities, and hydrophobicity of new developed coatings.
•HYDROBOND defined a protocol to investigate the interaction between small polymer chains and solid reinforcement particles.
•HYDROBOND procedure could be a useful screening test of new coating-mixtures
Milestone 8: Coating/paint deposition protocols and industrialization
The development of the coatings in the research part of the project focused on optimal coating properties. In these optimization steps, flat test parts were chosen to find the optimal spray parameters and to perform a variety of laboratory analyses. Flat surfaces are ideally to coat because the impact angle of the sprayed particles as well as the spray distance can be controlled in narrow limits. Different pre- and post-treatment steps can be tested under well-defined conditions and compared with respect to each other to find the optimum way to achieve a high coating quality.
The outcome of this optimization was a process protocol in which the different pre- and post-treatment steps were listed and the optimal spray conditions were defined.
In the figure12, panels come from and old LM17.0 blade used during test campaign, after coating trials
While as hybrid process does not differ from that for coating in laboratory samples, the LP-CGS process needs an improving in the up-scaling procedure relative to post-deposition stage. Concerning the CGS coatings, a protocol base in a European Patent was done:
EP17151460. 13 JANUARY 2017: Process for obtaining a dense superhydrophobic or hydrophobic, icephobic and wear resistant coating by means of Cold Gas Spray technique.
The invention relates to a process of production of a dense superhydrophobic or hydrophobic, icephobic and wear resistant coating by means of Cold Gas Spray technique, to the coatings obtained by said process, its use as coating in wind turbine blades, to a wind turbine blade comprising said coatings. Furthermore, the invention relates to the uses of said coatings as anti-fouling coatings, as self-cleaning architecture and as aircraft coatings, as well as the uses in the manufacture of civil engineering or machinery pieces and car, train or truck parts.
The invention related to a process for obtaining a dense and multifunctional properties coatings onto a substrate characterized in that it comprises the steps included in the scheme of the global process as the figure 13 shows:
From the industrial point of view, this post-deposition process for coatings consolidation needs considered to achieve to the thickness reduction target. Autoclave treatment processes have been considered to achieve the thickness reduction target at satisfaction because in function of the P and T parameters a significant change of coating thickness of 35% is compliance.
The figure 14 shows the effect of the thermomechanical post-treatment on the coating microstructure (cross-section, optical microscopy, before and after P/T Treatment)
Milestone9: Potential benefits establishment to increasing the wind EU Market
The potential benefits of project result are focus on Icephobic coatings. This market includes various transportation applications, all arctic – especially off-shore – building and energy applications and also heat exchangers and cooling applications
The hybrid coatings developed in HYDROBOND project show high durability in outdoor applications, low ice adhesion and good wear resistance. They can be applied using regular paint technology and can be adjusted for color and gloss according to customer demand. However, they do not prevent ice formation but ease ice detachment clearly compared to existing outdoor paints. Thus they have lot of application potential in many industries
The cold gas sprayed coatings (CGS) show promising wear resistance reaching 3 hours without erosion in RE test and 13hours in Jet Erosion test (ASTMG73-10) . The possibility of using CGS technology on an industrial level with autoclave post mechanical- heat treatment is promising both in the Wind Energy sector at the level of other smaller pieces and with metallic substrates and its extension is valuable in other fields
Milestone 10: Reduced scale wind blade prototype coated with new durable Superhydrophobic coatings
From the multiple technical tests conclusions are:
1.- Hybrids: Suitable Hybrids for industrialisation have been identified.
Other Hybrids have lower values in the RE test, however, these coatings seem good
candidates for other applications (bridges, cars, aeronautic,...) and have to be evaluated.
2.- CGS coatings: The last specimen has passed 10 hours in RE test and this is really good but for
large blades the CGS+autoclave treatment needs to be improved. However for small blades are factible and need to be test in industrial conditions following the protocol of the mentioned patent the same as for other type of applications.
From rain erosion (RE) test, the highest coating quality is reached by a combination of the coating application and a thermo-mechanical post-treatment of LP-CGS process but the difficulty to industrialize the post-treatment has caused that the real scaled blade prototype had to be the hybrid solution system.
Final Application
Muehlhan adquired a couple of Wind Generators Bonus 450/37 and additionally 6 wind blades model LM17.0 (Figure 4) have been acquired in orderto test survival ability???? of the solution in a harsh environment in Bremerhaven (Denmark).
Three windblades are in process to be painted for performance comparison between both generators. The results of this performance will immediately position one of the Hydrobond solutions in the market.No habría que añadir algo más de información aqui??? Queda un poco ligerito no?
Icephobic coatings market
The hybrid coatings and the CGS coatings developed in HYDROBOND project show multidisciplinary properties and particularly, Super-Hydrophobicity, low ice adhesion and good wear/rain erosion resistance. They can be applied using regular paint technology and also in coatings after the consolidation processes and they have lot of application potential in many industries
Icephobic coatings market includes various transportation applications, all arctic – especially off-shore – building and energy applications and also heat exchangers and cooling applications among others:
Off-shore structures
Off-shore industry includes oil and gas industry besides wind energy. Sea water sprays form ice on structures causing work hazards and machinery malfunctions. Icephobic coatings could decrease the amount of ice and ease its removal.
Marine industry
Ships that operate in arctic conditions suffer from ice accretion into structures. This creates working hazards and even unbalance to ship’s behaviour. Also deck machinery may be not usable due to ice formation. They are usually removed by mechanical hammering, steam or even electrical heating.
Aeronautic Industry
Icing has long been a critical issue in Aviation, not only a performance-affecting issue, but more so one compromising safety. Accidents due to ice accumulating in various parts of the aircraft are still today one of the main concerns of aviation safety authorities. It is for this reason that a parallel scenario could be envisaged, for the potential applications in the aviation sector of solutions found within the Hydrobond project for the Wind Turbine Industry.
Automotive Sector
Superhydrophobic solutions (Hydrobond results) could help increase the product life of car motors and body work as well as improving aesthetical aspects of appearance. Etos project was developed during last year in Germany (Putzier as a member of the project has a participation and contribution) and some solutions from Hydrobond were tested.
Ice and snow formation on antennas
Snow and ice accretion on antennas may deteriorate the reception of a broadcast. Loss of signals may happen while snow is melting: water film forming on antenna surface attenuates reception signals. The snow and ice accretion also increases the weight of the equipment, which may cause breakage or destruction. It is essential to prevent the snow or ice accretion from forming to protect equipment and structures.
Other Applications (Figure 15)
As a relationship of possible applications of the HYDROBOND products here there is a list other specific fields:
• Bridges (Cables, Railings) • Communication Towers
• Power Lines • Guy Wires
• Cables • Satellite Dishes
• Microwave Domes • Overpasses
• Elevated Walkways • Roof Edges
• Train Cars • Cars and truck
Potential Impact:
It is well known that wind turbines are one of the fastest growing sources of “green” power in the world today. There are now 141.578MW (141.6 GW) installed in EU with a total cumulative capacity of 147.771 MW (147.8 GW) for all of Europe. Wind power installed more than any other form of power generation in 2015, accounting for 44.2% of all power capacity installations.
Over the past twenty years, there has been a great deal of effort connected to the design of wind turbines, control systems, and energy storage systems to enable wind generation to be used in remote or hybrid power applications. The driving force behind the HYDROBOND project is the need for a step-wise acceleration of wind turbines for cold climate applications.
In fact, the overall expected impact of the HYDROBOND project was the reduction of weight of wind turbine blades increasing the reliability and operational life of blades, especially where an anti- and de-icing system (ADIS) is used in cold climate applications, and improving the costs of wind energy by reducing maintenance frequency and stops during their life cycle.
The improvement on cold climate wind energy production due to the implementation of SUPERHYDROPHOBIC coatings to blades could be increased up to 10-20% annually (due anti-icing and de-icing properties among other properties in blades).
According to HYDROBOND estimations more than 30 million tons of CO2 emissions will be reduced during the period 2017-2020 after the implementation of the super hydrophobic coatings developed within the Hydrobond Project. Since lower maintenance will be needed, transport to offshore wind farms will be reduced and hence, marine habitat will be less damaged. Higher efficiency of offshore wind turbines will result in more capacity of power generation and thus, less necessity for onshore wind farms.
Although the project is primarily aimed at the offshore market, the technology can equally be applied to onshor turbines in cold climates, where anti-icing and de-icing properties are essential.
The global superhydrophobic coating market was valued at USD 5.77 million in 2015. Rising demand for consumer electronics with highly water-repellent properties to protect sensitive data & components is a key factor driving market growth. (http://www.grandviewresearch.com/industry-analysis/superhydrophobic-coating-market)
Icephobic coatings are adaptable to a variety of developing applications. The “Hydrophobic Coatings and Surfaces: 2016-2023” report from the NanoMarkets Company n-tech Research projects the market for hydrophobic materials used for self-cleaning, de-icing, anti-fouling and anticorrosion applications will grow to $1.8 billion by 2021.
The above shortly mentioned shows that there is an increasing market and potential to solve ice related problems with advanced icephobic coatings. Aerospace industry has a clear need for decreasing the use of deicing chemicals but due to their costly and long approval process they are not the primary target of the developed coatings. Although the developed hybrid coatings did not pass the rain erosion test they showed excellent outdoor durability and icephobic behavior. Therefore new markets are looked from applications where erosive wear is not primary problem as in wind mill blades. However, outside leading edge, the developed coatings could offer benefits over conventional paints regarding ease of ice formation and detachment of formed ice. Statkraft has shown interest in testing icephobic coatings in their wind mill farm suffering from icing. The erosion resistance development will continue.
Three main project results have been pointed in term of exploitation:
- Hybrids coatings are showing a promising ice-detachment resistance and also have good ice formation avoidance characteristics. Therefore, they could be potential target for industries exposed to ice formation conditions.
- Cold Gas Spray has initially a big potential, as it could be applied on site without further curing as regular coatings. The opportunity is great but there are some process improvements that need to be overcome in order to provide a solution with positive business case.
- Standardization procedure: Jet erosion test was produced as a new method for rain effect on the substrates.
- During all the four years of the Project the consortium has been evaluated the full spectrum of exploitation and dissemination opportunities, including protecting the results through patents and IPR agreements.
Besides wind mills the main focus will be in offering the hybrid coating products for marine, transportation and construction industry and their service and subcontractor companies. The individual specifications will be verified and coatings modified to meet the demands.
Trains suffer from delays in winter conditions due to snow and ice. HYDROBOND developed icephobic coating technology is being tested in train cars in Finnish railways. Also the coatings developed in the HYDROBOND project will be offered for the subcontractors offering products for oil and gas industry.
During the Hydrobond project, some objectives from the point of view of dissemination have been achieved:
• Creating HYDROBOND web, Hydrobond website (www.hydro-bond.eu) was very dynamic in terms of news relatives to wind sector, and the consortium keep an intranet space where the partners share information, documents and also the meeting agendas and minutes.
• Link the Hydrobond webpage in the web sites of each partner.
•Referencing of HYDROBOND project in seminars and workshops & joining international conferences
Hydrobond partners have been present in different exhibitions from the wind energy sector, i.e.
► Winter Wind Energy Conference (Sweden), November 2014.
► EWEA (European Wind Energy Association) Annual Event . May2014 (Barcelona).
► International Thermal Spray Conference and Exhibition. June 2014 (Barcelona).
► EWEA OFFSHORE 2015 (Denmark).
► International Thermal Spray Conference and Exhibition .May 2015 (USA).
► 1st Innovation Workshop on Cold Gas Spray Technology. June 2015 (Spain).
► MATERIAIS, Porto, June 2015 (Portugal).
► International Conference European Ceramic Society: ECerS XIV (Spain2015).
► International Workshop on Atmospheric Icing of Structures (Sweden) 2015.
► Husum Wind 2015 (Germany).
► EWEA 2015. November 2015 (France).
► 2nd International Conference Offshore Substructures. February 2016. London UK.
► International Thermal Spray Conference, Shanghai, China, May 2016.
► EWEA 2016. Hamburg Messe. Sep 2016 .Germany.
Hydrobond was also presented in the 1st Workshop and General Assembly of the Engineering & Upscaling Cluster (12th February 2015, Brussels).
HYDROBOND consortium was very active belong of these years and also we don’t forget that all partners has been active in meetings of the consortium. In the following table, the different meetings are reported:
HYDROBOND MEETINGS
2013. Barcelona. Kick off meeting (31st January-1st February)
2013. Tampere. 6 month meeting (27th -28th June)
2014. Brussels. 12 month meeting (30th-31st January)
2014. Modena. 18 month meeting (26th-27th June)
2014 Barcelona. 21 month meeting (23rd October)
2015. Pamplona. 25 month meeting (5th-6th February)
2015. Teleconference. 29 month meeting (19th May)
2015. Helsinki. 30 month meeting (29th June)
2015. Paris. 35 month meeting (18th-19th November)
2016. Barcelona. Industrial meeting (8th January)
2016. Brussels. 38 moth meeting (4th-5th February)
2016. Teleconferences 19th April; 5th May; 19th May; 31st May; 28th June;
18th July; 4th October; 19th October; 7th & 23rd November;1st December
2016. Barcelona. 44 month meeting (12th-13rd September)
2016. Barcelona. International Network & Technical Meeting (21st-22rd & 23th November)
2017. Brussels. Final meeting (16th-17th January)
In November 2015 in occasion of the International EWEA meeting and exhibition held in Paris, Prof. Guilemany (coordinator of Hydrobond project) and the Project Management Cluster, besides technical and administrative activities has proposed to the exploitation and dissemination board the organization of an International Workshop in order to pool results and experiences between different European projects related to the WIND ENERGY sector. After consultation with the Programme Officer and PTA of the HYDROBOND project, the event was scheduled on November 2016 and the participation of the others granted EU projects was confirmed (Figure 17), with the following main objectives:
1. Bring Industry and science closer presenting challenges, ideas, methods and capabilities.
2. Having Wind Turbine owners addressing some of the major challenges operating windfarms.
3. Introduce the different European Projects related to WIND TURBINE Industry for sharing experiences in addressing the challenges in this sector.
4. Give industrial partners the possibilities to meet the scientific partners to present capabilities in each segment
5. Interaction between Industry Expert speakers presentations in conference and workshopping to get deep understanding of challenges and concepts
6. Finding new partners for new projects
7. Networking across the disciplines and among the participants.
With the participation of European projects:
ACORN : “Advanced Coatings for Offshore Renewable Energy”
JEDI- ACE: “Japanese-European De-Icing Aircraft Collaborative Exploration”
SUPRAPOWER: “SUPerconducting, Reliable, lightweight, And more POWERful offshore wind turbine”
ECOSWING: “Energy Cost Optimization using Superconducting Wind Generators - World’s First Demonstration of a 3.6 MW Low-Cost Lightweight DD Superconducting Generator on a Wind Turbine”
WALID: “Wind Blade Using Cost-Effective Advanced Composite Lightweight Design.”
NANOLEAP: “Nanocomposite for building constructions and civil infrastructures: European network pilot production line to promote industrial application cases.”
RIBLET4WIND: “ Riblet-Surfaces for Improvement of Efficiency of Wind Turbines”
LIBI: “Optimal Lightning Protection System.”
MARE-WINT: “New Materials and Reliability in offshore WINd Turbines Technology.“
DASHWIN: “ Development of Advanced Shearography System for On-Site Inspection of Wind Turbine Blades”
HYDROBOND: “New Cost/Effective Superhydrophobic Coatings with Enhanced Bond Strength and Wear Resistance for Application in Large Wind Turbine Blades“.
CL-Windcon: “Developing the next generation technologies of renewable electricity and heating/cooling”
During two days, 21st and 22nd of November, in Barcelona (Hotel Rey Don Jaime, Castelldefelds), the International Workshop took place with different activities related to the wind energy sector.
The coordinators of the EU sponsoring projects participated in the event showing the main results of the projects involved. More than 80 participants from industrial and academic sector from 14 different European countries joined in this forum.
According to the above, we obtain a series of issues that as a general conclusion are summarized in the following keywords and that should be developed / undertaken in future actions at European financial support level:
Keywords 1: The future wind blades should be maintenance-free
Keywords 2: Lack of engineers specialized in wind energy
Keywords 3: Change in industrial fabrication processes is required.
A special attention should be given to the introduction of new, modern and smart technologies:
New sensors for monitoring the degradation of materials in wind turbines
New algorithms for control
Application of additive manufacturing technologies
Self-healing materials
New technologies for predictive maintenance
New technologies for onsite repairing
New manufacturing processes, automatization, standardization, economies of scale
The coordinators of all 12 European Projects take the responsibility to produce a document at beginning of January 2017 as preliminary draft in order to be approved for all the consortiums before the end of March 2017.
Detailed descriptions of the conclusions of this workshop were distributed inside to the EU for Wind Energy and Renewable energies using the facilities of our Programme Officer linked to HYDROBOND (Figure 18).
During the beginning of the project the consortium has evaluated the patenting the results of the project and concerning the CGS coatings a protocol base in a European Patent was done:
EP17151460. 13 JANUARY 2017: Process for obtaining a dense superhydrophobic or hydrophobic, icephobic and wear resistant coating by means of Cold Gas Spray technique.
The invention relates to a process of obtainment of a dense superhydrophobic or hydrophobic, icephobic and wear resistant coating by means of Cold Gas Spray technique, to the coatings obtained by said process, its use as coating in wind turbine blades, to a wind turbine blade comprising said coatings. Furthermore, the invention relates to the uses of said coatings as anti-fouling coatings, as self-cleaning architecture and as aircraft coatings, as well as the uses in the manufacture of civil engineering or machinery pieces and car, train or truck parts.
This is one of the reasons why today the most relevant results have not yet been published because patenting the results of the project was always under serious consideration
However two dissemination papers where authorized by the consortium concerning a noncritical secrecy results:
1. Winterwind conference (6-8 February, 2017, Skellefteå, Sweden); Figure 19
2. International Workshop on Atmospheric Icing Structures (28June-3July, Uppsala, Sweden, 2015). Figure 20
Dissemination will be continued through different ways and also the HYDROBOND website will be active during two years after the project finishing.
The main actions inside to the Exploitation were:
•To explore the commercialization of products developed in the project (powder/resins/hybrids/coatings).
•To contact with other application interested in anti-icing behaviour. Millidyne has some business companies interested with the transport sector
•LM (Danish Blade Manufacturing Company) collaboration. LM offers two turbine (has bought by MUDK) placed very close to shore with 6 blades that were coated with the HYDROBOND solution on April 2017.
•Other application in transport sector, like decoration as KE showed in Etos project (supported by Putzier).
•To explore the commercialization of products developed in the project inside to the Blade Damage and Repair industrial sector.
•To explore the commercialization of an specific testing protocol (standardization) and a new Device, the Jet Erosion Test, has been built up to evaluate the resistance to water abrasion of the coatings to simulate blades in real working conditions. The Jet Erosion Test, have been carried out by editing a video shown presented in the Brussels meeting (5th of February 2016) to show the facility and the potential benefit of the test to the wind turbine industry. This video is today available in YouTube since April 2016:
https://www.youtube.com/watch?v=A9eO6rwHwjs
List of Websites:
www.hydro-bond.eu
www.cptub.com
c/ Marti i Franques, 1
Barcelona 08028
