Making the case for new renewable energy materials

Paul Boughton
There is no single solution to the many challenges of future energy harvesting. There will be a number of solutions, but it is certain that wind and solar energy will play an important part. Thierry Perchet reports.

Wind is a valued renewable source of energy because it is constantly being produced, is plentiful, widely distributed, clean and produces no greenhouse gas emissions. Governments and energy utilities across the world are embracing wind power because it can compete with conventional energy sources such as oil and gas - not just in terms of the environment, but also on the grounds of cost.

Huntsman's product range covers the whole chain of wind blade production, from seamless modelling pastes for master models, gel coats and resins for mould production to Germanischer Lloyd, GL, certified resins and adhesives for part production and materials which can also be used for on-site repair.

One example of where Huntsman materials are being used is for wind blade work in partnership with Composite Technology Centre, CTC, who chose Araldite resins for the production of composite wind blades through a closed infusion process. The Araldite system that CTC selected was the GL approved Araldite LY 1564/Aradur 3416.

Commenting on the choice of resin system, Jos ter Laak, MD CTC, said: "For a number of years we have worked with Huntsman on an infusion system which has excellent mechanical properties as well a number of attractive operational features such as a low viscosity, a long pot life and a fast increase of glass transition temperature during the pre-cure cycle to match the requirements of the internal structure of the wind blade."

Another advantage is that the Huntsman resin is not sensitive to variations to the environmental temperature during process. In other words, it is a robust system with regard to processing temperatures.

To capture the maximum energy from the wind, the wind blades have to be large, stiff and sufficiently robust to withstand every weather condition. The largest blades designed by CTC are 50 metres in length with Araldite resin contributing about a third to their weight of approximately 10 tonnes.

The chosen Araldite system improves temperature resistance and toughness, all particularly important features if the wind blades are to withstand adverse weather conditions. The result is new composite wind blades for onshore and offshore wind energy generation.

Huntsman continues to invest in these market developments in order to cope with the increasing mechanical property demands of large wind blades. For example, the company has launched new Araldite products at JEC 2010 with enhanced mechanical and process capabilities:

- Araldite AW 4870 / Hardener HW 4870.

- AralditeAW 4871 / Hardener HW 4871.

- Araldite AW 4856 / Hardener HW 4856 (Gl approved).

Smart building and solar energy

Twenty-first century objectives of new building construction are based on 'positive energy balance'. This does not mean disconnection from the grid, but that the average energy consumption should be lower than the building is able to produce. Right at the start one should focus on optimised insulation. Reflective coatings minimising infra red absorption, usage of urethane sandwich panels, insulation boards and blocks are all areas where Huntsman is very active. Without doubt we will see a rise in their use in warm climates.

Solar heating, solar reflective and solar power are areas of growth where Huntsman is also actively working with partners in order to help improve efficiency and bring down production costs.

Solar thermal panel design has become more refined and efficient, to the extent that now solar heating panels can be an integral and virtually indistinguishable part of the roof design. Adhesives, fixings and sealants specifically designed for these panels will see increased usage.

Alongside solar heating and solar reflective technology there will be a massive growth in solar power arrays to produce electricity from sunlight. Traditionally, silicon wafer technology has always been used, but in future whole areas of roofing may have photovoltaic cells installed which will produce a significant proportion of the energy for the building.

Huntsman is currently actively working with its partners in order to help to improve the efficiency and bring down the production costs of photovoltaic modules. For example, Huntsman has teamed up with CAITEN GmbH, a leading Austrian engineering company providing solar solutions using advanced liquid polymers. It focuses on innovative module concepts which compare favourably to standard systems in terms of build-up, processing, thermal management, inter-connection and costs so as to work in adverse southern climates and deserts.

Modules are already 15 per cent more effective and can be optimised up to a 30 per cent higher yield. Currently there are intensive material tests going on, after which this technology will become commercially available in 2011.

Another example of Huntsman's work in the solar energy market is Araldite 2015 which has TUV design and type approval for PV modules. What makes Araldite 2015 different is that it allows a module design and construction with improved heat transfer and efficiency together with excellent strength and bonding properties. Often improved heat transfer properties necessary for solar panel output efficiency are only achieved at the sacrifice of bonding features.

Araldite 2015 properties of high shear and peel strength, resistance to water and chemicals and resistance to UV are not affected when used for improved energy efficient solar panels in buildings. Tests prove that bonding of the aluminium extruded profiles bonded onto the surface treated polyvinyl fluoride back sheet of the solar module can withstand thermal cycling temperature cycles from -40°C up to 85°C without diminishing the strength of the bond. It makes Araldite 2015 suited to dissimilar materials.

The energy value chain concept and the broad range of Huntsman products makes the company the first choice for customers seeking innovative solutions.

The way mankind generates, stores and consumes energy is the key to protecting the biosphere, remediation of ecological damage, and enhancing the health and well-being of future generations. Focussing on energy and anticipating tomorrow's needs for alternative energy defines the direction of our research and development. Huntsman Advanced Materials is a global leader and a pioneer in applications that benefit our customers, consumers and the planet as a whole. To name just a few areas where we are currently working: wind and solar markets, OLEDs (organic light emitting devices) and fuel cell applications are exciting green fields where Huntsman is actively involved.

- Thierry Perchet is European Marketing Director, Huntsman Advanced Materials, Basel, Switzerland.