1.  Introduction: Minimising losses, optimising cooling
2.  Server cabinet installations in the computer centre: cold and warm aisles
2.1  Cold air coming from above
2.2  Cold air coming from below
3.  Optimisation stage 1: Radial fans in the rear doors
4.  Optimisation stage 2: Covering the cold aisle
5.  Optimisation stage 3: Additionally closing the cold aisle front and rear
6.  Optimisation stage 4: Water-cooled doors on the exit side of the servers
7.  Optimisation stage 5: Water-cooled doors on the entry side of the servers
8.  Optimisation stage 6: Closed cell with two AWHEs (LHX 20) at front and rear
9.  Optimisation stage 7: Air-conditioning for safety only
10.  Conclusion