WinUAE, the emulation engine of AmiKit, is configured to use all of the PC's power for Amiga emulation. That is why your processor is always 100% busy and the heat increases.
To avoid this, go to WinUAE/CPU settings and move the CPU Idle slider more to the right. This way you assign less CPU power for emulation which results in slightly slower emulation but CPU fan won't get crazy.
In addition you might want to enable "Pause emulation" options in WinUAE/Pri.&Extensions settings. This way anytime you switch to Windows, the emulation gets paused and saves the CPU (and fan).