AGING TEST BED
The concentrator prototype made use of the stretched membrane technique, which maintains the parabolic shape with a small vacuum pump. It has 94% reflectivity and can concentrate the sunlight up to 12,000 times in its 12‑cm-diameter focus. It has a focal distance of 4.5 meters and polar solar tracking. Two DISTAL I units were disassembled in the year 2000 and replaced by third generation EUROdish units.
In operation since 1992, this installation initially consisted of 3 7.5‑m-diameter parabolic dish units capable of collecting up to 40 kWt energy with a SOLO V160 9‑kWe Stirling motor located in its focal zone.
The DISTAL II was a first attempt at a system with better features and per-kWe cost. Three new stretched-membrane prototypes were erected and put into routine operation in 1996 and 1997. Their slightly larger 8.5‑m-diameter delivers 50 kWt to the motor. The focal distance is 4.1 m and the maximum concentration is 16,000 suns at the focus. The Stirling motor, which had also evolved, is now a 10‑kWe SOLO V161 and the tracking system is azimuth-elevation, which allows automatic sunrise-to-sunset operation.