OT cd read write

Just bought me a new cdrw because my old one just did not read every time I used it ;-(. This new cdrw 52x24x52 from Asus is much faster then the old one 2x read but what I found strange is that every time the cd drive reads a data disk it starts making a noise during the read. It seems to be a fan working overtime. Think it is normal but I just wanted to know why a fan is build in this cdrw.