Thanks for the comments.
The Curtains are animated with Bullet engine. The setup is attached as image. Curtain needs to be Deforming Object with Weightmap as Mesh Filter and a Null Object with an turbulence Force Field. The calculated results have to exported as .mdd file. In the scene you have to attach the .mdd file to the curtain with -> Deform-> MD Reader.
To be able to move the curtain to its individual space and with its its deformation local use "Apply Cache to: Object Space"
When Rendering the GI Cache File u have to check Allow Animation to get it work right. In my case to avoid splotches within the curtains i have use the "unseen by rays" checkbox. Take a look at the attachment.
Render times were very different between the scenes. On my fastest workstation it was between about 7min until 30min per frame (1280x720px). I have used the car paint shaders for some of the pillows. I believe that was not a good decision in case of render time.