New compressor plant
Since 1999 a new fully computer controlled compressor system is operational. The system with nominal power of 220 kW is a lot less powerful than the old one. A refill of the 300 cubic meter vessel now takes approximately 7 hours in comparison to 20 minutes for the old plant. The modern system consists of an oilfree screw in the first stage and a reciprocating booster compressor in the second stage. The new high pressure air dryer reaches a much better dryness level of less than 10 PPM water content in the air.
The storage vessel
The dry air is stored in a 300 cubic meter pressure vessel. Fully charged, this reservoir contains approximately 14300 kgs of air. In the pressure vessel a heat regenerator has been installed, consisting of a bed of some 20000 kgs of ceramic pebbles. When compressed air is delivered to the wind tunnels, the temperature of the stored air drops as the pressure in the vessel decreases. The heat regenerator maintains a nearly constant temperature of the delivered air by dissipating heat to the outflowing air.
As fine probes which are susceptible to erosion by dust particles are frequently used in the wind tunnels a high-pressure 5 micron dust filter has been installed in the piping system between the pressure vessel and the wind tunnels.