The inner overpressure is constantly maintained by blowers. In reality, there is always some air loss as it is almost impossible to build a large inflated structure which is completely airtight. Moreover, the atmospheric barometric pressure changes caused by good and bad weather are much larger than the inner pressure inside, so an automated regulation and compensation is required.

 

The inner pressure is a few mBar, enough to compensate for wind loads. As a comparative value, a man can inflate a balloon with 150-200 mBar pressure, and the tires of a car are inflated with 2500 mBar. So when there is an air loss due to a puncture, the air escapes very slowly and it would take up to 1 hour to deflate the structure completely without external blowers becoming active. It is for this reason that keeping the pressure inside is rather simple.

 

Plastic is currently a very generic term and encloses hundreds of polymers and byproducts. The film used in our product comprises two types: ETFE Ethylene tetrafluoroethylene, and Mylar. Both are very high quality polymers. ETFE is a Teflon-based polymer which is currently used as a replacement for glass in greenhouses. It has excellent self-cleaning properties and is very scratch resistant. It is very transparent to UV radiation so there is no degradation due to exposure to the sun. Many large and modern structures are built with this material.

Bubbles Building Olympic Stadium.

 

ETFE does not burn asit is fire retardant. For this reason, it is currently being used in civil engineering. If exposed to high temperatures (> 260°C) it will simply melt. The same is also true for Mylar, although not as fire retardant as ETFE, it behaves rather well additives.

Yes, ETFE can operate at temperature reaching  160 °C and Mylar 150 °C which is well above environmental conditions which  may at times reach a temperature of 50°C.

 

The great advantage of its concrete frame is that the construction industry is very mature in dealing with such kind of structures. Concrete is the first construction materialin the world. So building 100 M€ concrete structure is actually not much compared to a bridge or even a large building such as a hospital. For this reason, schedules can be rather tight: 1-1.5 years are certainly enough in any part of the world. A further great advantage is that there is no bottleneck in the delivery of mirrors due to the fact that the production of our Mylar film is so extensiveworldwide that in 3 hours a medium-sized company could produce the entire film required for a power plant.

 

A power plant is divided in several main elements:  if there is a failure in one of the systems, a single row may simply  be stopped and the overall solar field power output is reduced by a small percentage. The electric output can be kept constant by temporarily using more energy from the storage, until the damage is repaired.

The packed bed storage system is a very old concept, used mainly in chemistry and  it is a concept which has been proven by means of  several theoretical and practical analyses.. In principle, the packed bed exploits the low thermal conductivity properties of stone and air to keep a internal thermal gradient between the hot top portion of the tank and the cold lower part. While “loading”, the slow hot air flows along with the large volumetric surface of the gravel, guaranteeing that the heat transported by air is completely transferred to the stones. Such process is reversible by blowing cold air from the bottom of the tank (cold side). The outlet temperature is constant until the tank is almost “empty”.