Kernel CPU usage shows more than 100%, temperature low, fan speed high
Not sure where you get the CPU temperature but it does not seem to be accurate, if the CPU usage is so high.

For detailed and accurate report on the CPU I use 

that creates report like this 



To possibly solve your mystery...

Open Console in your Utility Folder

The Type "Kernel" in the search box.

Now you can see what Kernel is busy with.

You can copy and paste here for us to help you with reading.



In this case my kernel is running at 6% CPU