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Aby Daniela Grancini

Made in SwitzerlandA refl ecting membrane capable of capturing energy, a rigid but lightweight supporting structure, a test system which defi es the heat of North Africa. The start up of Airlight Energy the result of great minds and great determination

to diathermic oil or molten salts) and produces heat which is then stored in a storage system or diverted directly to an exchanger which creates steam and powers the turbine. Thus electricity is created.The great innovation of this idea lies in the fact of using an aluminised polyester membrane welded into three rolls to create an extremely large refl ecting mirror in an alternative material to glass (which is too fragile and diffi cult to clean) or aluminium. This makes it possible to concentrate 200 suns, against the standard 50.

Testing of the inventionDr. Giovanni Martinola, head of the department of Materials Sciences of Airlight Energy and lecturer in concrete technologies at the Zurich Federal Polytechnic, explained to us that the distance between the focalisation point and the membrane was excessive in the fi rst prototype and the receiver was extremely exposed to ambient temperature and atmospheric agents.

Airlight Energy has recently completed a thermodynamic plant in Ait Baha, near Agadir, in Morocco: an extremely

innovative and cutting-edge plant in the alternative energy fi eld. The structure is integrated into the cement plant of Ciments du Maroc (Italcementi Group) and has been fully designed by Airlight Energy.

Everything startedwith a membraneFollowing a request from an Australian university for a study on renewable energies, the Airlight Energy technicians asked themselves if it would be possible to use totally refl ecting membranes to concentrate solar energy in a «fi re». This led to a series of prototypes and patents (around 20) aimed at creating the so-called CSP, Concentrated Solar Power, which, through a system of mirrors, channels solar energy on a point, uses air as a medium (as an alternative

WHO IS AIRLIGHT ENERGYAirlight Energy is a privately-owned Swiss company off ering high-technology solutions in the sector of solar energy for large-scale electricity and thermal energy production and energy storage. It opened in 2007 in Biasca, in Switzerland, and has a workforce of sixty employees, as well as around twenty fi led patents. It marked the passage from the start-up phase to the commercial one with the huge solar plant project at Ait Baha, in Morocco, which will have a production capacity of 2000 MW by 2020: an industrial application destined to be a milestone in the solar technology sector. Numerous scientifi c and business partnerships have marked the fi rst seven years of Airlight Energy activities: these include the Paul Scherrer Institut, Energie Schweiz, Lausanne Polytechnic, Eni. With IBM, Airlight Energy is completing an innovative system which uses solar energy, capable of generating up to 2000 suns and supplying, with a single unit, electricity, hot water, desalinated water and conditioned air. The areas of application of Airlight Energy solutions, besides the industrial ones (production of energy, cement, paper, ecc.) include agriculture, building and water desalination

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«We had to protect the receiver, limit heat loss and bring it inside the membrane close to the mirror, in order completely to control losses, which were also due to the double passage of the light through it».Another prototype was therefore chosen, a manifold constructed as a tensile structure in an almost completely transparent ETFE membrane used for years in Dutch greenhouses and agriculture, a self-cleaning polymer, extremely resistant and transparent across the entire light spectrum. A step forward, but not the fi nal one. In order to obtain an optimum result, it was necessary to perfect the geometry of the mirror, approximating its shape to a parabola in order to concentrate the refl ected light in a single point, without using a secondary mirror. This lead to the fi nal version, which incorporates a surprising idea: use of concrete (rather than steel or aluminium) as the supporting material of the entire optical system.

Lightness and stabilityAirlight Energy has in its DNA the design of rigid but lightweight structures in the building sector, and this is obviously not a conventional material, but self-compacting and fi bre-reinforced concrete, in which part of the reinforcement is integrated, with mechanical properties which are three times superior to the RCK

30 concrete used in 95% of cases.New, completely closed formworks were used, formed of many coupled cast aluminium sheets to obtain non-standard shapes. The self-compacting concrete is laid without using external compacting energy, fi lling of the product requires around 15 minutes (around 23 cm3 of concrete), while the hardening times are

decidedly reduced.

Laboratory geniuses«Our task is controlling the incoming raw materials which, once mixed with water, form the concrete», says Dr. Giovanni Martinola. «We conduct around thirty tests on these materials». Over recent months, Airlight Energy has been assessing and attempting to patent fi bre-reinforced

ADVANTEST OF CONTROLS ALSO FUNCTIONS IN THE DESERTThe equipment in the Airlight Energy mobile laboratory in Morocco, housed in a 40-foot container and used for quality tests, also includes the Controls Advantest system, the second which the company has purchased. «We need particularly reliable equipment, since at Ait Baha the structure has been used up to the maximum capacity, for a total of 50 compressions and 20 pieces produced per day «- explains Dr. Giovanni Martinola, head of the department of Materials Sciences of Airlight Energy and lecturer in concrete technologies at the Zurich Federal Polytechnic.The advantages of ADVANTEST:allows automatic performance of low-frequency static and dynamic load, displacement and deformation tests, which can be extensively customised by the operator;allows control variables (load, displacement, deformation), speed, target and all retroaction parameters to be changed while the test is in progress;performance of compression, fl exure and indirect tensile strength tests;precision and reliability even in intensive operating conditions

http://www.controls-group.com/eng/

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A WINNING IDEAWelding of the aluminised membrane strips is the stroke of genius which provided sufficiently wide surfaces to cover the optical part. The ETFE (ethylene tetrafluoroethylene) film of around one and half meters is welded to reach up to 212 meters in length of the manifold. The sheet is stretched automatically, using two LAEM System Cutting Edge Technology welding machines, and, once welded, the rolls are assembled, loaded and sent to Morocco.

materials with fl exural and tensile strength close to that of aluminium, an impossible objective up until very recently, since the gap between conduct under tensile stress of an aluminium alloy and concrete was huge. In the laboratory, we also noted a compression testing machine, constructed by Airlight Energy ad hoc for determination of cubic compression strength to the order of 500/600 Mega Pascal, ten times higher than those of standard concretes. The testing machine enhances operation with and Advantest system, a servo-hydraulic power and control system by Controls. «Relations with Controls are excellent», says Martinola. «It is a dynamic, enthusiastic and skilled company which does not abandon the customer once the machine has been sold. We greatly appreciated its fl exibility and support in our integrations to the product and the supply times, as well as the excellent price/quality ratio.»

molivares@controls.it

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